shell/hush.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * sh.c -- a prototype Bourne shell grammar parser
   4  *      Intended to follow the original Thompson and Ritchie
   5  *      "small and simple is beautiful" philosophy, which
   6  *      incidentally is a good match to today's BusyBox.
   7  *
   8  * Copyright (C) 2000,2001  Larry Doolittle  <larry@doolittle.boa.org>
   9  *
  10  * Credits:
  11  *      The parser routines proper are all original material, first
  12  *      written Dec 2000 and Jan 2001 by Larry Doolittle.  The
  13  *      execution engine, the builtins, and much of the underlying
  14  *      support has been adapted from busybox-0.49pre's lash, which is
  15  *      Copyright (C) 1999-2003 by Erik Andersen <andersen@codepoet.org>
  16  *      written by Erik Andersen <andersen@codepoet.org>.  That, in turn,
  17  *      is based in part on ladsh.c, by Michael K. Johnson and Erik W.
  18  *      Troan, which they placed in the public domain.  I don't know
  19  *      how much of the Johnson/Troan code has survived the repeated
  20  *      rewrites.
  21  *
  22  * Other credits:
  23  *      simple_itoa() was lifted from boa-0.93.15
  24  *      b_addchr() derived from similar w_addchar function in glibc-2.2
  25  *      setup_redirect(), redirect_opt_num(), and big chunks of main()
  26  *        and many builtins derived from contributions by Erik Andersen
  27  *      miscellaneous bugfixes from Matt Kraai
  28  *
  29  * There are two big (and related) architecture differences between
  30  * this parser and the lash parser.  One is that this version is
  31  * actually designed from the ground up to understand nearly all
  32  * of the Bourne grammar.  The second, consequential change is that
  33  * the parser and input reader have been turned inside out.  Now,
  34  * the parser is in control, and asks for input as needed.  The old
  35  * way had the input reader in control, and it asked for parsing to
  36  * take place as needed.  The new way makes it much easier to properly
  37  * handle the recursion implicit in the various substitutions, especially
  38  * across continuation lines.
  39  *
  40  * Bash grammar not implemented: (how many of these were in original sh?)
  41  *      $@ (those sure look like weird quoting rules)
  42  *      $_
  43  *      ! negation operator for pipes
  44  *      &> and >& redirection of stdout+stderr
  45  *      Brace Expansion
  46  *      Tilde Expansion
  47  *      fancy forms of Parameter Expansion
  48  *      aliases
  49  *      Arithmetic Expansion
  50  *      <(list) and >(list) Process Substitution
  51  *      reserved words: case, esac, select, function
  52  *      Here Documents ( << word )
  53  *      Functions
  54  * Major bugs:
  55  *      job handling woefully incomplete and buggy
  56  *      reserved word execution woefully incomplete and buggy
  57  * to-do:
  58  *      port selected bugfixes from post-0.49 busybox lash - done?
  59  *      finish implementing reserved words: for, while, until, do, done
  60  *      change { and } from special chars to reserved words
  61  *      builtins: break, continue, eval, return, set, trap, ulimit
  62  *      test magic exec
  63  *      handle children going into background
  64  *      clean up recognition of null pipes
  65  *      check setting of global_argc and global_argv
  66  *      control-C handling, probably with longjmp
  67  *      follow IFS rules more precisely, including update semantics
  68  *      figure out what to do with backslash-newline
  69  *      explain why we use signal instead of sigaction
  70  *      propagate syntax errors, die on resource errors?
  71  *      continuation lines, both explicit and implicit - done?
  72  *      memory leak finding and plugging - done?
  73  *      more testing, especially quoting rules and redirection
  74  *      document how quoting rules not precisely followed for variable assignments
  75  *      maybe change map[] to use 2-bit entries
  76  *      (eventually) remove all the printf's
  77  *
  78  * This program is free software; you can redistribute it and/or modify
  79  * it under the terms of the GNU General Public License as published by
  80  * the Free Software Foundation; either version 2 of the License, or
  81  * (at your option) any later version.
  82  *
  83  * This program is distributed in the hope that it will be useful,
  84  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  85  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  86  * General Public License for more details.
  87  *
  88  * You should have received a copy of the GNU General Public License
  89  * along with this program; if not, write to the Free Software
  90  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  91  */
  92 #include <ctype.h>     /* isalpha, isdigit */
  93 #include <unistd.h>    /* getpid */
  94 #include <stdlib.h>    /* getenv, atoi */
  95 #include <string.h>    /* strchr */
  96 #include <stdio.h>     /* popen etc. */
  97 #include <glob.h>      /* glob, of course */
  98 #include <stdarg.h>    /* va_list */
  99 #include <errno.h>
 100 #include <fcntl.h>
 101 #include <getopt.h>    /* should be pretty obvious */
 102
 103 #include <sys/stat.h>  /* ulimit */
 104 #include <sys/types.h>
 105 #include <sys/wait.h>
 106 #include <signal.h>
 107
 108 /* #include <dmalloc.h> */
 109 /* #define DEBUG_SHELL */
 110
 111 #if 1
 112 #include "busybox.h"
 113 #include "cmdedit.h"
 114 #else
 115 #define bb_applet_name "hush"
 116 #include "standalone.h"
 117 #define hush_main main
 118 #undef CONFIG_FEATURE_SH_FANCY_PROMPT
 119 #define BB_BANNER
 120 #endif
 121 #define SPECIAL_VAR_SYMBOL 03
 122 #define FLAG_EXIT_FROM_LOOP 1
 123 #define FLAG_PARSE_SEMICOLON (1 << 1)           /* symbol ';' is special for parser */
 124 #define FLAG_REPARSING           (1 << 2)               /* >=2nd pass */
 125
 126 typedef enum {
 127         REDIRECT_INPUT     = 1,
 128         REDIRECT_OVERWRITE = 2,
 129         REDIRECT_APPEND    = 3,
 130         REDIRECT_HEREIS    = 4,
 131         REDIRECT_IO        = 5
 132 } redir_type;
 133
 134 /* The descrip member of this structure is only used to make debugging
 135  * output pretty */
 136 struct {int mode; int default_fd; char *descrip;} redir_table[] = {
 137         { 0,                         0, "()" },
 138         { O_RDONLY,                  0, "<"  },
 139         { O_CREAT|O_TRUNC|O_WRONLY,  1, ">"  },
 140         { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
 141         { O_RDONLY,                 -1, "<<" },
 142         { O_RDWR,                    1, "<>" }
 143 };
 144
 145 typedef enum {
 146         PIPE_SEQ = 1,
 147         PIPE_AND = 2,
 148         PIPE_OR  = 3,
 149         PIPE_BG  = 4,
 150 } pipe_style;
 151
 152 /* might eventually control execution */
 153 typedef enum {
 154         RES_NONE  = 0,
 155         RES_IF    = 1,
 156         RES_THEN  = 2,
 157         RES_ELIF  = 3,
 158         RES_ELSE  = 4,
 159         RES_FI    = 5,
 160         RES_FOR   = 6,
 161         RES_WHILE = 7,
 162         RES_UNTIL = 8,
 163         RES_DO    = 9,
 164         RES_DONE  = 10,
 165         RES_XXXX  = 11,
 166         RES_IN    = 12,
 167         RES_SNTX  = 13
 168 } reserved_style;
 169 #define FLAG_END   (1<<RES_NONE)
 170 #define FLAG_IF    (1<<RES_IF)
 171 #define FLAG_THEN  (1<<RES_THEN)
 172 #define FLAG_ELIF  (1<<RES_ELIF)
 173 #define FLAG_ELSE  (1<<RES_ELSE)
 174 #define FLAG_FI    (1<<RES_FI)
 175 #define FLAG_FOR   (1<<RES_FOR)
 176 #define FLAG_WHILE (1<<RES_WHILE)
 177 #define FLAG_UNTIL (1<<RES_UNTIL)
 178 #define FLAG_DO    (1<<RES_DO)
 179 #define FLAG_DONE  (1<<RES_DONE)
 180 #define FLAG_IN    (1<<RES_IN)
 181 #define FLAG_START (1<<RES_XXXX)
 182
 183 /* This holds pointers to the various results of parsing */
 184 struct p_context {
 185         struct child_prog *child;
 186         struct pipe *list_head;
 187         struct pipe *pipe;
 188         struct redir_struct *pending_redirect;
 189         reserved_style w;
 190         int old_flag;                           /* for figuring out valid reserved words */
 191         struct p_context *stack;
 192         int type;                       /* define type of parser : ";$" common or special symbol */
 193         /* How about quoting status? */
 194 };
 195
 196 struct redir_struct {
 197         redir_type type;                        /* type of redirection */
 198         int fd;                                         /* file descriptor being redirected */
 199         int dup;                                        /* -1, or file descriptor being duplicated */
 200         struct redir_struct *next;      /* pointer to the next redirect in the list */
 201         glob_t word;                            /* *word.gl_pathv is the filename */
 202 };
 203
 204 struct child_prog {
 205         pid_t pid;                                      /* 0 if exited */
 206         char **argv;                            /* program name and arguments */
 207         struct pipe *group;                     /* if non-NULL, first in group or subshell */
 208         int subshell;                           /* flag, non-zero if group must be forked */
 209         struct redir_struct *redirects; /* I/O redirections */
 210         glob_t glob_result;                     /* result of parameter globbing */
 211         int is_stopped;                         /* is the program currently running? */
 212         struct pipe *family;            /* pointer back to the child's parent pipe */
 213         int sp;                         /* number of SPECIAL_VAR_SYMBOL */
 214         int type;
 215 };
 216
 217 struct pipe {
 218         int jobid;                                      /* job number */
 219         int num_progs;                          /* total number of programs in job */
 220         int running_progs;                      /* number of programs running */
 221         char *text;                                     /* name of job */
 222         char *cmdbuf;                           /* buffer various argv's point into */
 223         pid_t pgrp;                                     /* process group ID for the job */
 224         struct child_prog *progs;       /* array of commands in pipe */
 225         struct pipe *next;                      /* to track background commands */
 226         int stopped_progs;                      /* number of programs alive, but stopped */
 227         int job_context;                        /* bitmask defining current context */
 228         pipe_style followup;            /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
 229         reserved_style r_mode;          /* supports if, for, while, until */
 230 };
 231
 232 struct close_me {
 233         int fd;
 234         struct close_me *next;
 235 };
 236
 237 struct variables {
 238         char *name;
 239         char *value;
 240         int flg_export;
 241         int flg_read_only;
 242         struct variables *next;
 243 };
 244
 245 /* globals, connect us to the outside world
 246  * the first three support $?, $#, and $1 */
 247 char **global_argv;
 248 unsigned int global_argc;
 249 unsigned int last_return_code;
 250 extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
 251
 252 /* "globals" within this file */
 253 static char *ifs;
 254 static char map[256];
 255 static int fake_mode;
 256 static int interactive;
 257 static struct close_me *close_me_head;
 258 static const char *cwd;
 259 static struct pipe *job_list;
 260 static unsigned int last_bg_pid;
 261 static unsigned int last_jobid;
 262 static unsigned int shell_terminal;
 263 static char *PS1;
 264 static char *PS2;
 265 struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
 266 struct variables *top_vars = &shell_ver;
 267
 268
 269 #define B_CHUNK (100)
 270 #define B_NOSPAC 1
 271
 272 typedef struct {
 273         char *data;
 274         int length;
 275         int maxlen;
 276         int quote;
 277         int nonnull;
 278 } o_string;
 279 #define NULL_O_STRING {NULL,0,0,0,0}
 280 /* used for initialization:
 281         o_string foo = NULL_O_STRING; */
 282
 283 /* I can almost use ordinary FILE *.  Is open_memstream() universally
 284  * available?  Where is it documented? */
 285 struct in_str {
 286         const char *p;
 287         char peek_buf[2];
 288         int __promptme;
 289         int promptmode;
 290         FILE *file;
 291         int (*get) (struct in_str *);
 292         int (*peek) (struct in_str *);
 293 };
 294 #define b_getch(input) ((input)->get(input))
 295 #define b_peek(input) ((input)->peek(input))
 296
 297 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
 298
 299 struct built_in_command {
 300         char *cmd;                                      /* name */
 301         char *descr;                            /* description */
 302         int (*function) (struct child_prog *);  /* function ptr */
 303 };
 304
 305 /* belongs in busybox.h */
 306 static inline int max(int a, int b) {
 307         return (a>b)?a:b;
 308 }
 309
 310 /* This should be in utility.c */
 311 #ifdef DEBUG_SHELL
 312 static void debug_printf(const char *format, ...)
 313 {
 314         va_list args;
 315         va_start(args, format);
 316         vfprintf(stderr, format, args);
 317         va_end(args);
 318 }
 319 #else
 320 static inline void debug_printf(const char *format, ...) { }
 321 #endif
 322 #define final_printf debug_printf
 323
 324 static void __syntax(char *file, int line) {
 325         bb_error_msg("syntax error %s:%d", file, line);
 326 }
 327 #define syntax() __syntax(__FILE__, __LINE__)
 328
 329 /* Index of subroutines: */
 330 /*   function prototypes for builtins */
 331 static int builtin_cd(struct child_prog *child);
 332 static int builtin_env(struct child_prog *child);
 333 static int builtin_eval(struct child_prog *child);
 334 static int builtin_exec(struct child_prog *child);
 335 static int builtin_exit(struct child_prog *child);
 336 static int builtin_export(struct child_prog *child);
 337 static int builtin_fg_bg(struct child_prog *child);
 338 static int builtin_help(struct child_prog *child);
 339 static int builtin_jobs(struct child_prog *child);
 340 static int builtin_pwd(struct child_prog *child);
 341 static int builtin_read(struct child_prog *child);
 342 static int builtin_set(struct child_prog *child);
 343 static int builtin_shift(struct child_prog *child);
 344 static int builtin_source(struct child_prog *child);
 345 static int builtin_umask(struct child_prog *child);
 346 static int builtin_unset(struct child_prog *child);
 347 static int builtin_not_written(struct child_prog *child);
 348 /*   o_string manipulation: */
 349 static int b_check_space(o_string *o, int len);
 350 static int b_addchr(o_string *o, int ch);
 351 static void b_reset(o_string *o);
 352 static int b_addqchr(o_string *o, int ch, int quote);
 353 static int b_adduint(o_string *o, unsigned int i);
 354 /*  in_str manipulations: */
 355 static int static_get(struct in_str *i);
 356 static int static_peek(struct in_str *i);
 357 static int file_get(struct in_str *i);
 358 static int file_peek(struct in_str *i);
 359 static void setup_file_in_str(struct in_str *i, FILE *f);
 360 static void setup_string_in_str(struct in_str *i, const char *s);
 361 /*  close_me manipulations: */
 362 static void mark_open(int fd);
 363 static void mark_closed(int fd);
 364 static void close_all(void);
 365 /*  "run" the final data structures: */
 366 static char *indenter(int i);
 367 static int free_pipe_list(struct pipe *head, int indent);
 368 static int free_pipe(struct pipe *pi, int indent);
 369 /*  really run the final data structures: */
 370 static int setup_redirects(struct child_prog *prog, int squirrel[]);
 371 static int run_list_real(struct pipe *pi);
 372 static void pseudo_exec(struct child_prog *child) __attribute__ ((noreturn));
 373 static int run_pipe_real(struct pipe *pi);
 374 /*   extended glob support: */
 375 static int globhack(const char *src, int flags, glob_t *pglob);
 376 static int glob_needed(const char *s);
 377 static int xglob(o_string *dest, int flags, glob_t *pglob);
 378 /*   variable assignment: */
 379 static int is_assignment(const char *s);
 380 /*   data structure manipulation: */
 381 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
 382 static void initialize_context(struct p_context *ctx);
 383 static int done_word(o_string *dest, struct p_context *ctx);
 384 static int done_command(struct p_context *ctx);
 385 static int done_pipe(struct p_context *ctx, pipe_style type);
 386 /*   primary string parsing: */
 387 static int redirect_dup_num(struct in_str *input);
 388 static int redirect_opt_num(o_string *o);
 389 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
 390 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
 391 static char *lookup_param(char *src);
 392 static char *make_string(char **inp);
 393 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
 394 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
 395 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
 396 /*   setup: */
 397 static int parse_stream_outer(struct in_str *inp, int flag);
 398 static int parse_string_outer(const char *s, int flag);
 399 static int parse_file_outer(FILE *f);
 400 /*   job management: */
 401 static int checkjobs(struct pipe* fg_pipe);
 402 static void insert_bg_job(struct pipe *pi);
 403 static void remove_bg_job(struct pipe *pi);
 404 /*     local variable support */
 405 static char **make_list_in(char **inp, char *name);
 406 static char *insert_var_value(char *inp);
 407 static char *get_local_var(const char *var);
 408 static void  unset_local_var(const char *name);
 409 static int set_local_var(const char *s, int flg_export);
 410
 411 /* Table of built-in functions.  They can be forked or not, depending on
 412  * context: within pipes, they fork.  As simple commands, they do not.
 413  * When used in non-forking context, they can change global variables
 414  * in the parent shell process.  If forked, of course they can not.
 415  * For example, 'unset foo | whatever' will parse and run, but foo will
 416  * still be set at the end. */
 417 static struct built_in_command bltins[] = {
 418         {"bg", "Resume a job in the background", builtin_fg_bg},
 419         {"break", "Exit for, while or until loop", builtin_not_written},
 420         {"cd", "Change working directory", builtin_cd},
 421         {"continue", "Continue for, while or until loop", builtin_not_written},
 422         {"env", "Print all environment variables", builtin_env},
 423         {"eval", "Construct and run shell command", builtin_eval},
 424         {"exec", "Exec command, replacing this shell with the exec'd process",
 425                 builtin_exec},
 426         {"exit", "Exit from shell()", builtin_exit},
 427         {"export", "Set environment variable", builtin_export},
 428         {"fg", "Bring job into the foreground", builtin_fg_bg},
 429         {"jobs", "Lists the active jobs", builtin_jobs},
 430         {"pwd", "Print current directory", builtin_pwd},
 431         {"read", "Input environment variable", builtin_read},
 432         {"return", "Return from a function", builtin_not_written},
 433         {"set", "Set/unset shell local variables", builtin_set},
 434         {"shift", "Shift positional parameters", builtin_shift},
 435         {"trap", "Trap signals", builtin_not_written},
 436         {"ulimit","Controls resource limits", builtin_not_written},
 437         {"umask","Sets file creation mask", builtin_umask},
 438         {"unset", "Unset environment variable", builtin_unset},
 439         {".", "Source-in and run commands in a file", builtin_source},
 440         {"help", "List shell built-in commands", builtin_help},
 441         {NULL, NULL, NULL}
 442 };
 443
 444 static const char *set_cwd(void)
 445 {
 446         if(cwd==bb_msg_unknown)
 447                 cwd = NULL;     /* xgetcwd(arg) called free(arg) */
 448         cwd = xgetcwd((char *)cwd);
 449         if (!cwd)
 450                 cwd = bb_msg_unknown;
 451         return cwd;
 452 }
 453
 454 /* built-in 'eval' handler */
 455 static int builtin_eval(struct child_prog *child)
 456 {
 457         char *str = NULL;
 458         int rcode = EXIT_SUCCESS;
 459
 460         if (child->argv[1]) {
 461                 str = make_string(child->argv + 1);
 462                 parse_string_outer(str, FLAG_EXIT_FROM_LOOP |
 463                                         FLAG_PARSE_SEMICOLON);
 464                 free(str);
 465                 rcode = last_return_code;
 466         }
 467         return rcode;
 468 }
 469
 470 /* built-in 'cd <path>' handler */
 471 static int builtin_cd(struct child_prog *child)
 472 {
 473         char *newdir;
 474         if (child->argv[1] == NULL)
 475                 newdir = getenv("HOME");
 476         else
 477                 newdir = child->argv[1];
 478         if (chdir(newdir)) {
 479                 printf("cd: %s: %s\n", newdir, strerror(errno));
 480                 return EXIT_FAILURE;
 481         }
 482         set_cwd();
 483         return EXIT_SUCCESS;
 484 }
 485
 486 /* built-in 'env' handler */
 487 static int builtin_env(struct child_prog *dummy)
 488 {
 489         char **e = environ;
 490         if (e == NULL) return EXIT_FAILURE;
 491         for (; *e; e++) {
 492                 puts(*e);
 493         }
 494         return EXIT_SUCCESS;
 495 }
 496
 497 /* built-in 'exec' handler */
 498 static int builtin_exec(struct child_prog *child)
 499 {
 500         if (child->argv[1] == NULL)
 501                 return EXIT_SUCCESS;   /* Really? */
 502         child->argv++;
 503         pseudo_exec(child);
 504         /* never returns */
 505 }
 506
 507 /* built-in 'exit' handler */
 508 static int builtin_exit(struct child_prog *child)
 509 {
 510         if (child->argv[1] == NULL)
 511                 exit(last_return_code);
 512         exit (atoi(child->argv[1]));
 513 }
 514
 515 /* built-in 'export VAR=value' handler */
 516 static int builtin_export(struct child_prog *child)
 517 {
 518         int res = 0;
 519         char *name = child->argv[1];
 520
 521         if (name == NULL) {
 522                 return (builtin_env(child));
 523         }
 524
 525         name = strdup(name);
 526
 527         if(name) {
 528                 char *value = strchr(name, '=');
 529
 530                 if (!value) {
 531                         char *tmp;
 532                         /* They are exporting something without an =VALUE */
 533
 534                         value = get_local_var(name);
 535                         if (value) {
 536                                 size_t ln = strlen(name);
 537
 538                                 tmp = realloc(name, ln+strlen(value)+2);
 539                                 if(tmp==NULL)
 540                                         res = -1;
 541                                 else {
 542                                         sprintf(tmp+ln, "=%s", value);
 543                                         name = tmp;
 544                                 }
 545                         } else {
 546                                 /* bash does not return an error when trying to export
 547                                  * an undefined variable.  Do likewise. */
 548                                 res = 1;
 549                         }
 550                 }
 551         }
 552         if (res<0)
 553                 bb_perror_msg("export");
 554         else if(res==0)
 555                 res = set_local_var(name, 1);
 556         else
 557                 res = 0;
 558         free(name);
 559         return res;
 560 }
 561
 562 /* built-in 'fg' and 'bg' handler */
 563 static int builtin_fg_bg(struct child_prog *child)
 564 {
 565         int i, jobnum;
 566         struct pipe *pi=NULL;
 567
 568         if (!interactive)
 569                 return EXIT_FAILURE;
 570         /* If they gave us no args, assume they want the last backgrounded task */
 571         if (!child->argv[1]) {
 572                 for (pi = job_list; pi; pi = pi->next) {
 573                         if (pi->jobid == last_jobid) {
 574                                 break;
 575                         }
 576                 }
 577                 if (!pi) {
 578                         bb_error_msg("%s: no current job", child->argv[0]);
 579                         return EXIT_FAILURE;
 580                 }
 581         } else {
 582                 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
 583                         bb_error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
 584                         return EXIT_FAILURE;
 585                 }
 586                 for (pi = job_list; pi; pi = pi->next) {
 587                         if (pi->jobid == jobnum) {
 588                                 break;
 589                         }
 590                 }
 591                 if (!pi) {
 592                         bb_error_msg("%s: %d: no such job", child->argv[0], jobnum);
 593                         return EXIT_FAILURE;
 594                 }
 595         }
 596
 597         if (*child->argv[0] == 'f') {
 598                 /* Put the job into the foreground.  */
 599                 tcsetpgrp(shell_terminal, pi->pgrp);
 600         }
 601
 602         /* Restart the processes in the job */
 603         for (i = 0; i < pi->num_progs; i++)
 604                 pi->progs[i].is_stopped = 0;
 605
 606         if ( (i=kill(- pi->pgrp, SIGCONT)) < 0) {
 607                 if (i == ESRCH) {
 608                         remove_bg_job(pi);
 609                 } else {
 610                         bb_perror_msg("kill (SIGCONT)");
 611                 }
 612         }
 613
 614         pi->stopped_progs = 0;
 615         return EXIT_SUCCESS;
 616 }
 617
 618 /* built-in 'help' handler */
 619 static int builtin_help(struct child_prog *dummy)
 620 {
 621         struct built_in_command *x;
 622
 623         printf("\nBuilt-in commands:\n");
 624         printf("-------------------\n");
 625         for (x = bltins; x->cmd; x++) {
 626                 if (x->descr==NULL)
 627                         continue;
 628                 printf("%s\t%s\n", x->cmd, x->descr);
 629         }
 630         printf("\n\n");
 631         return EXIT_SUCCESS;
 632 }
 633
 634 /* built-in 'jobs' handler */
 635 static int builtin_jobs(struct child_prog *child)
 636 {
 637         struct pipe *job;
 638         char *status_string;
 639
 640         for (job = job_list; job; job = job->next) {
 641                 if (job->running_progs == job->stopped_progs)
 642                         status_string = "Stopped";
 643                 else
 644                         status_string = "Running";
 645
 646                 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
 647         }
 648         return EXIT_SUCCESS;
 649 }
 650
 651
 652 /* built-in 'pwd' handler */
 653 static int builtin_pwd(struct child_prog *dummy)
 654 {
 655         puts(set_cwd());
 656         return EXIT_SUCCESS;
 657 }
 658
 659 /* built-in 'read VAR' handler */
 660 static int builtin_read(struct child_prog *child)
 661 {
 662         int res;
 663
 664         if (child->argv[1]) {
 665                 char string[BUFSIZ];
 666                 char *var = 0;
 667
 668                 string[0] = 0;  /* In case stdin has only EOF */
 669                 /* read string */
 670                 fgets(string, sizeof(string), stdin);
 671                 chomp(string);
 672                 var = malloc(strlen(child->argv[1])+strlen(string)+2);
 673                 if(var) {
 674                         sprintf(var, "%s=%s", child->argv[1], string);
 675                         res = set_local_var(var, 0);
 676                 } else
 677                         res = -1;
 678                 if (res)
 679                         fprintf(stderr, "read: %m\n");
 680                 free(var);      /* So not move up to avoid breaking errno */
 681                 return res;
 682         } else {
 683                 do res=getchar(); while(res!='\n' && res!=EOF);
 684                 return 0;
 685         }
 686 }
 687
 688 /* built-in 'set VAR=value' handler */
 689 static int builtin_set(struct child_prog *child)
 690 {
 691         char *temp = child->argv[1];
 692         struct variables *e;
 693
 694         if (temp == NULL)
 695                 for(e = top_vars; e; e=e->next)
 696                         printf("%s=%s\n", e->name, e->value);
 697         else
 698                 set_local_var(temp, 0);
 699
 700                 return EXIT_SUCCESS;
 701 }
 702
 703
 704 /* Built-in 'shift' handler */
 705 static int builtin_shift(struct child_prog *child)
 706 {
 707         int n=1;
 708         if (child->argv[1]) {
 709                 n=atoi(child->argv[1]);
 710         }
 711         if (n>=0 && n<global_argc) {
 712                 /* XXX This probably breaks $0 */
 713                 global_argc -= n;
 714                 global_argv += n;
 715                 return EXIT_SUCCESS;
 716         } else {
 717                 return EXIT_FAILURE;
 718         }
 719 }
 720
 721 /* Built-in '.' handler (read-in and execute commands from file) */
 722 static int builtin_source(struct child_prog *child)
 723 {
 724         FILE *input;
 725         int status;
 726
 727         if (child->argv[1] == NULL)
 728                 return EXIT_FAILURE;
 729
 730         /* XXX search through $PATH is missing */
 731         input = fopen(child->argv[1], "r");
 732         if (!input) {
 733                 bb_error_msg("Couldn't open file '%s'", child->argv[1]);
 734                 return EXIT_FAILURE;
 735         }
 736
 737         /* Now run the file */
 738         /* XXX argv and argc are broken; need to save old global_argv
 739          * (pointer only is OK!) on this stack frame,
 740          * set global_argv=child->argv+1, recurse, and restore. */
 741         mark_open(fileno(input));
 742         status = parse_file_outer(input);
 743         mark_closed(fileno(input));
 744         fclose(input);
 745         return (status);
 746 }
 747
 748 static int builtin_umask(struct child_prog *child)
 749 {
 750         mode_t new_umask;
 751         const char *arg = child->argv[1];
 752         char *end;
 753         if (arg) {
 754                 new_umask=strtoul(arg, &end, 8);
 755                 if (*end!='\0' || end == arg) {
 756                         return EXIT_FAILURE;
 757                 }
 758         } else {
 759                 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
 760         }
 761         umask(new_umask);
 762         return EXIT_SUCCESS;
 763 }
 764
 765 /* built-in 'unset VAR' handler */
 766 static int builtin_unset(struct child_prog *child)
 767 {
 768         /* bash returned already true */
 769         unset_local_var(child->argv[1]);
 770         return EXIT_SUCCESS;
 771 }
 772
 773 static int builtin_not_written(struct child_prog *child)
 774 {
 775         printf("builtin_%s not written\n",child->argv[0]);
 776         return EXIT_FAILURE;
 777 }
 778
 779 static int b_check_space(o_string *o, int len)
 780 {
 781         /* It would be easy to drop a more restrictive policy
 782          * in here, such as setting a maximum string length */
 783         if (o->length + len > o->maxlen) {
 784                 char *old_data = o->data;
 785                 /* assert (data == NULL || o->maxlen != 0); */
 786                 o->maxlen += max(2*len, B_CHUNK);
 787                 o->data = realloc(o->data, 1 + o->maxlen);
 788                 if (o->data == NULL) {
 789                         free(old_data);
 790                 }
 791         }
 792         return o->data == NULL;
 793 }
 794
 795 static int b_addchr(o_string *o, int ch)
 796 {
 797         debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
 798         if (b_check_space(o, 1)) return B_NOSPAC;
 799         o->data[o->length] = ch;
 800         o->length++;
 801         o->data[o->length] = '\0';
 802         return 0;
 803 }
 804
 805 static void b_reset(o_string *o)
 806 {
 807         o->length = 0;
 808         o->nonnull = 0;
 809         if (o->data != NULL) *o->data = '\0';
 810 }
 811
 812 static void b_free(o_string *o)
 813 {
 814         b_reset(o);
 815         free(o->data);
 816         o->data = NULL;
 817         o->maxlen = 0;
 818 }
 819
 820 /* My analysis of quoting semantics tells me that state information
 821  * is associated with a destination, not a source.
 822  */
 823 static int b_addqchr(o_string *o, int ch, int quote)
 824 {
 825         if (quote && strchr("*?[\\",ch)) {
 826                 int rc;
 827                 rc = b_addchr(o, '\\');
 828                 if (rc) return rc;
 829         }
 830         return b_addchr(o, ch);
 831 }
 832
 833 /* belongs in utility.c */
 834 char *simple_itoa(unsigned int i)
 835 {
 836         /* 21 digits plus null terminator, good for 64-bit or smaller ints */
 837         static char local[22];
 838         char *p = &local[21];
 839         *p-- = '\0';
 840         do {
 841                 *p-- = '0' + i % 10;
 842                 i /= 10;
 843         } while (i > 0);
 844         return p + 1;
 845 }
 846
 847 static int b_adduint(o_string *o, unsigned int i)
 848 {
 849         int r;
 850         char *p = simple_itoa(i);
 851         /* no escape checking necessary */
 852         do r=b_addchr(o, *p++); while (r==0 && *p);
 853         return r;
 854 }
 855
 856 static int static_get(struct in_str *i)
 857 {
 858         int ch=*i->p++;
 859         if (ch=='\0') return EOF;
 860         return ch;
 861 }
 862
 863 static int static_peek(struct in_str *i)
 864 {
 865         return *i->p;
 866 }
 867
 868 static inline void cmdedit_set_initial_prompt(void)
 869 {
 870 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
 871         PS1 = NULL;
 872 #else
 873         PS1 = getenv("PS1");
 874         if(PS1==0)
 875                 PS1 = "\\w \\$ ";
 876 #endif
 877 }
 878
 879 static inline void setup_prompt_string(int promptmode, char **prompt_str)
 880 {
 881         debug_printf("setup_prompt_string %d ",promptmode);
 882 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
 883         /* Set up the prompt */
 884         if (promptmode == 1) {
 885                 free(PS1);
 886                 PS1=xmalloc(strlen(cwd)+4);
 887                 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
 888                 *prompt_str = PS1;
 889         } else {
 890                 *prompt_str = PS2;
 891         }
 892 #else
 893         *prompt_str = (promptmode==1)? PS1 : PS2;
 894 #endif
 895         debug_printf("result %s\n",*prompt_str);
 896 }
 897
 898 static void get_user_input(struct in_str *i)
 899 {
 900         char *prompt_str;
 901         static char the_command[BUFSIZ];
 902
 903         setup_prompt_string(i->promptmode, &prompt_str);
 904 #ifdef CONFIG_FEATURE_COMMAND_EDITING
 905         /*
 906          ** enable command line editing only while a command line
 907          ** is actually being read; otherwise, we'll end up bequeathing
 908          ** atexit() handlers and other unwanted stuff to our
 909          ** child processes (rob@sysgo.de)
 910          */
 911         cmdedit_read_input(prompt_str, the_command);
 912 #else
 913         fputs(prompt_str, stdout);
 914         fflush(stdout);
 915         the_command[0]=fgetc(i->file);
 916         the_command[1]='\0';
 917 #endif
 918         fflush(stdout);
 919         i->p = the_command;
 920 }
 921
 922 /* This is the magic location that prints prompts
 923  * and gets data back from the user */
 924 static int file_get(struct in_str *i)
 925 {
 926         int ch;
 927
 928         ch = 0;
 929         /* If there is data waiting, eat it up */
 930         if (i->p && *i->p) {
 931                 ch=*i->p++;
 932         } else {
 933                 /* need to double check i->file because we might be doing something
 934                  * more complicated by now, like sourcing or substituting. */
 935                 if (i->__promptme && interactive && i->file == stdin) {
 936                         while(! i->p || (interactive && strlen(i->p)==0) ) {
 937                                 get_user_input(i);
 938                         }
 939                         i->promptmode=2;
 940                         i->__promptme = 0;
 941                         if (i->p && *i->p) {
 942                                 ch=*i->p++;
 943                         }
 944                 } else {
 945                         ch = fgetc(i->file);
 946                 }
 947
 948                 debug_printf("b_getch: got a %d\n", ch);
 949         }
 950         if (ch == '\n') i->__promptme=1;
 951         return ch;
 952 }
 953
 954 /* All the callers guarantee this routine will never be
 955  * used right after a newline, so prompting is not needed.
 956  */
 957 static int file_peek(struct in_str *i)
 958 {
 959         if (i->p && *i->p) {
 960                 return *i->p;
 961         } else {
 962                 i->peek_buf[0] = fgetc(i->file);
 963                 i->peek_buf[1] = '\0';
 964                 i->p = i->peek_buf;
 965                 debug_printf("b_peek: got a %d\n", *i->p);
 966                 return *i->p;
 967         }
 968 }
 969
 970 static void setup_file_in_str(struct in_str *i, FILE *f)
 971 {
 972         i->peek = file_peek;
 973         i->get = file_get;
 974         i->__promptme=1;
 975         i->promptmode=1;
 976         i->file = f;
 977         i->p = NULL;
 978 }
 979
 980 static void setup_string_in_str(struct in_str *i, const char *s)
 981 {
 982         i->peek = static_peek;
 983         i->get = static_get;
 984         i->__promptme=1;
 985         i->promptmode=1;
 986         i->p = s;
 987 }
 988
 989 static void mark_open(int fd)
 990 {
 991         struct close_me *new = xmalloc(sizeof(struct close_me));
 992         new->fd = fd;
 993         new->next = close_me_head;
 994         close_me_head = new;
 995 }
 996
 997 static void mark_closed(int fd)
 998 {
 999         struct close_me *tmp;
1000         if (close_me_head == NULL || close_me_head->fd != fd)
1001                 bb_error_msg_and_die("corrupt close_me");
1002         tmp = close_me_head;
1003         close_me_head = close_me_head->next;
1004         free(tmp);
1005 }
1006
1007 static void close_all(void)
1008 {
1009         struct close_me *c;
1010         for (c=close_me_head; c; c=c->next) {
1011                 close(c->fd);
1012         }
1013         close_me_head = NULL;
1014 }
1015
1016 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
1017  * and stderr if they are redirected. */
1018 static int setup_redirects(struct child_prog *prog, int squirrel[])
1019 {
1020         int openfd, mode;
1021         struct redir_struct *redir;
1022
1023         for (redir=prog->redirects; redir; redir=redir->next) {
1024                 if (redir->dup == -1 && redir->word.gl_pathv == NULL) {
1025                         /* something went wrong in the parse.  Pretend it didn't happen */
1026                         continue;
1027                 }
1028                 if (redir->dup == -1) {
1029                         mode=redir_table[redir->type].mode;
1030                         openfd = open(redir->word.gl_pathv[0], mode, 0666);
1031                         if (openfd < 0) {
1032                         /* this could get lost if stderr has been redirected, but
1033                            bash and ash both lose it as well (though zsh doesn't!) */
1034                                 bb_perror_msg("error opening %s", redir->word.gl_pathv[0]);
1035                                 return 1;
1036                         }
1037                 } else {
1038                         openfd = redir->dup;
1039                 }
1040
1041                 if (openfd != redir->fd) {
1042                         if (squirrel && redir->fd < 3) {
1043                                 squirrel[redir->fd] = dup(redir->fd);
1044                         }
1045                         if (openfd == -3) {
1046                                 close(openfd);
1047                         } else {
1048                                 dup2(openfd, redir->fd);
1049                                 if (redir->dup == -1)
1050                                         close (openfd);
1051                         }
1052                 }
1053         }
1054         return 0;
1055 }
1056
1057 static void restore_redirects(int squirrel[])
1058 {
1059         int i, fd;
1060         for (i=0; i<3; i++) {
1061                 fd = squirrel[i];
1062                 if (fd != -1) {
1063                         /* No error checking.  I sure wouldn't know what
1064                          * to do with an error if I found one! */
1065                         dup2(fd, i);
1066                         close(fd);
1067                 }
1068         }
1069 }
1070
1071 /* never returns */
1072 /* XXX no exit() here.  If you don't exec, use _exit instead.
1073  * The at_exit handlers apparently confuse the calling process,
1074  * in particular stdin handling.  Not sure why? */
1075 static void pseudo_exec(struct child_prog *child)
1076 {
1077         int i, rcode;
1078         char *p;
1079         struct built_in_command *x;
1080         if (child->argv) {
1081                 for (i=0; is_assignment(child->argv[i]); i++) {
1082                         debug_printf("pid %d environment modification: %s\n",getpid(),child->argv[i]);
1083                         p = insert_var_value(child->argv[i]);
1084                         putenv(strdup(p));
1085                         if (p != child->argv[i]) free(p);
1086                 }
1087                 child->argv+=i;  /* XXX this hack isn't so horrible, since we are about
1088                                         to exit, and therefore don't need to keep data
1089                                         structures consistent for free() use. */
1090                 /* If a variable is assigned in a forest, and nobody listens,
1091                  * was it ever really set?
1092                  */
1093                 if (child->argv[0] == NULL) {
1094                         _exit(EXIT_SUCCESS);
1095                 }
1096
1097                 /*
1098                  * Check if the command matches any of the builtins.
1099                  * Depending on context, this might be redundant.  But it's
1100                  * easier to waste a few CPU cycles than it is to figure out
1101                  * if this is one of those cases.
1102                  */
1103                 for (x = bltins; x->cmd; x++) {
1104                         if (strcmp(child->argv[0], x->cmd) == 0 ) {
1105                                 debug_printf("builtin exec %s\n", child->argv[0]);
1106                                 rcode = x->function(child);
1107                                 fflush(stdout);
1108                                 _exit(rcode);
1109                         }
1110                 }
1111
1112                 /* Check if the command matches any busybox internal commands
1113                  * ("applets") here.
1114                  * FIXME: This feature is not 100% safe, since
1115                  * BusyBox is not fully reentrant, so we have no guarantee the things
1116                  * from the .bss are still zeroed, or that things from .data are still
1117                  * at their defaults.  We could exec ourself from /proc/self/exe, but I
1118                  * really dislike relying on /proc for things.  We could exec ourself
1119                  * from global_argv[0], but if we are in a chroot, we may not be able
1120                  * to find ourself... */
1121 #ifdef CONFIG_FEATURE_SH_STANDALONE_SHELL
1122                 {
1123                         int argc_l;
1124                         char** argv_l=child->argv;
1125                         char *name = child->argv[0];
1126
1127 #ifdef CONFIG_FEATURE_SH_APPLETS_ALWAYS_WIN
1128                         /* Following discussions from November 2000 on the busybox mailing
1129                          * list, the default configuration, (without
1130                          * bb_get_last_path_component()) lets the user force use of an
1131                          * external command by specifying the full (with slashes) filename.
1132                          * If you enable CONFIG_FEATURE_SH_APPLETS_ALWAYS_WIN, then applets
1133                          * _aways_ override external commands, so if you want to run
1134                          * /bin/cat, it will use BusyBox cat even if /bin/cat exists on the
1135                          * filesystem and is _not_ busybox.  Some systems may want this,
1136                          * most do not.  */
1137                         name = bb_get_last_path_component(name);
1138 #endif
1139                         /* Count argc for use in a second... */
1140                         for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1141                         optind = 1;
1142                         debug_printf("running applet %s\n", name);
1143                         run_applet_by_name(name, argc_l, child->argv);
1144                 }
1145 #endif
1146                 debug_printf("exec of %s\n",child->argv[0]);
1147                 execvp(child->argv[0],child->argv);
1148                 bb_perror_msg("couldn't exec: %s",child->argv[0]);
1149                 _exit(1);
1150         } else if (child->group) {
1151                 debug_printf("runtime nesting to group\n");
1152                 interactive=0;    /* crucial!!!! */
1153                 rcode = run_list_real(child->group);
1154                 /* OK to leak memory by not calling free_pipe_list,
1155                  * since this process is about to exit */
1156                 _exit(rcode);
1157         } else {
1158                 /* Can happen.  See what bash does with ">foo" by itself. */
1159                 debug_printf("trying to pseudo_exec null command\n");
1160                 _exit(EXIT_SUCCESS);
1161         }
1162 }
1163
1164 static void insert_bg_job(struct pipe *pi)
1165 {
1166         struct pipe *thejob;
1167
1168         /* Linear search for the ID of the job to use */
1169         pi->jobid = 1;
1170         for (thejob = job_list; thejob; thejob = thejob->next)
1171                 if (thejob->jobid >= pi->jobid)
1172                         pi->jobid = thejob->jobid + 1;
1173
1174         /* add thejob to the list of running jobs */
1175         if (!job_list) {
1176                 thejob = job_list = xmalloc(sizeof(*thejob));
1177         } else {
1178                 for (thejob = job_list; thejob->next; thejob = thejob->next) /* nothing */;
1179                 thejob->next = xmalloc(sizeof(*thejob));
1180                 thejob = thejob->next;
1181         }
1182
1183         /* physically copy the struct job */
1184         memcpy(thejob, pi, sizeof(struct pipe));
1185         thejob->next = NULL;
1186         thejob->running_progs = thejob->num_progs;
1187         thejob->stopped_progs = 0;
1188         thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */
1189
1190         //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1191         {
1192                 char *bar=thejob->text;
1193                 char **foo=pi->progs[0].argv;
1194                 while(foo && *foo) {
1195                         bar += sprintf(bar, "%s ", *foo++);
1196                 }
1197         }
1198
1199         /* we don't wait for background thejobs to return -- append it
1200            to the list of backgrounded thejobs and leave it alone */
1201         printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1202         last_bg_pid = thejob->progs[0].pid;
1203         last_jobid = thejob->jobid;
1204 }
1205
1206 /* remove a backgrounded job */
1207 static void remove_bg_job(struct pipe *pi)
1208 {
1209         struct pipe *prev_pipe;
1210
1211         if (pi == job_list) {
1212                 job_list = pi->next;
1213         } else {
1214                 prev_pipe = job_list;
1215                 while (prev_pipe->next != pi)
1216                         prev_pipe = prev_pipe->next;
1217                 prev_pipe->next = pi->next;
1218         }
1219         if (job_list)
1220                 last_jobid = job_list->jobid;
1221         else
1222                 last_jobid = 0;
1223
1224         pi->stopped_progs = 0;
1225         free_pipe(pi, 0);
1226         free(pi);
1227 }
1228
1229 /* Checks to see if any processes have exited -- if they
1230    have, figure out why and see if a job has completed */
1231 static int checkjobs(struct pipe* fg_pipe)
1232 {
1233         int attributes;
1234         int status;
1235         int prognum = 0;
1236         struct pipe *pi;
1237         pid_t childpid;
1238
1239         attributes = WUNTRACED;
1240         if (fg_pipe==NULL) {
1241                 attributes |= WNOHANG;
1242         }
1243
1244         while ((childpid = waitpid(-1, &status, attributes)) > 0) {
1245                 if (fg_pipe) {
1246                         int i, rcode = 0;
1247                         for (i=0; i < fg_pipe->num_progs; i++) {
1248                                 if (fg_pipe->progs[i].pid == childpid) {
1249                                         if (i==fg_pipe->num_progs-1)
1250                                                 rcode=WEXITSTATUS(status);
1251                                         (fg_pipe->num_progs)--;
1252                                         return(rcode);
1253                                 }
1254                         }
1255                 }
1256
1257                 for (pi = job_list; pi; pi = pi->next) {
1258                         prognum = 0;
1259                         while (prognum < pi->num_progs && pi->progs[prognum].pid != childpid) {
1260                                 prognum++;
1261                         }
1262                         if (prognum < pi->num_progs)
1263                                 break;
1264                 }
1265
1266                 if(pi==NULL) {
1267                         debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
1268                         continue;
1269                 }
1270
1271                 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1272                         /* child exited */
1273                         pi->running_progs--;
1274                         pi->progs[prognum].pid = 0;
1275
1276                         if (!pi->running_progs) {
1277                                 printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
1278                                 remove_bg_job(pi);
1279                         }
1280                 } else {
1281                         /* child stopped */
1282                         pi->stopped_progs++;
1283                         pi->progs[prognum].is_stopped = 1;
1284
1285 #if 0
1286                         /* Printing this stuff is a pain, since it tends to
1287                          * overwrite the prompt an inconveinient moments.  So
1288                          * don't do that.  */
1289                         if (pi->stopped_progs == pi->num_progs) {
1290                                 printf("\n"JOB_STATUS_FORMAT, pi->jobid, "Stopped", pi->text);
1291                         }
1292 #endif
1293                 }
1294         }
1295
1296         if (childpid == -1 && errno != ECHILD)
1297                 bb_perror_msg("waitpid");
1298
1299         /* move the shell to the foreground */
1300         //if (interactive && tcsetpgrp(shell_terminal, getpgid(0)))
1301         //      bb_perror_msg("tcsetpgrp-2");
1302         return -1;
1303 }
1304
1305 /* Figure out our controlling tty, checking in order stderr,
1306  * stdin, and stdout.  If check_pgrp is set, also check that
1307  * we belong to the foreground process group associated with
1308  * that tty.  The value of shell_terminal is needed in order to call
1309  * tcsetpgrp(shell_terminal, ...); */
1310 void controlling_tty(int check_pgrp)
1311 {
1312         pid_t curpgrp;
1313
1314         if ((curpgrp = tcgetpgrp(shell_terminal = 2)) < 0
1315                         && (curpgrp = tcgetpgrp(shell_terminal = 0)) < 0
1316                         && (curpgrp = tcgetpgrp(shell_terminal = 1)) < 0)
1317                 goto shell_terminal_error;
1318
1319         if (check_pgrp && curpgrp != getpgid(0))
1320                 goto shell_terminal_error;
1321
1322         return;
1323
1324 shell_terminal_error:
1325                 shell_terminal = -1;
1326                 return;
1327 }
1328
1329 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1330  * to finish.  See checkjobs().
1331  *
1332  * return code is normally -1, when the caller has to wait for children
1333  * to finish to determine the exit status of the pipe.  If the pipe
1334  * is a simple builtin command, however, the action is done by the
1335  * time run_pipe_real returns, and the exit code is provided as the
1336  * return value.
1337  *
1338  * The input of the pipe is always stdin, the output is always
1339  * stdout.  The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1340  * because it tries to avoid running the command substitution in
1341  * subshell, when that is in fact necessary.  The subshell process
1342  * now has its stdout directed to the input of the appropriate pipe,
1343  * so this routine is noticeably simpler.
1344  */
1345 static int run_pipe_real(struct pipe *pi)
1346 {
1347         int i;
1348         int nextin, nextout;
1349         int pipefds[2];                         /* pipefds[0] is for reading */
1350         struct child_prog *child;
1351         struct built_in_command *x;
1352         char *p;
1353
1354         nextin = 0;
1355         pi->pgrp = -1;
1356
1357         /* Check if this is a simple builtin (not part of a pipe).
1358          * Builtins within pipes have to fork anyway, and are handled in
1359          * pseudo_exec.  "echo foo | read bar" doesn't work on bash, either.
1360          */
1361         if (pi->num_progs == 1) child = & (pi->progs[0]);
1362         if (pi->num_progs == 1 && child->group && child->subshell == 0) {
1363                 int squirrel[] = {-1, -1, -1};
1364                 int rcode;
1365                 debug_printf("non-subshell grouping\n");
1366                 setup_redirects(child, squirrel);
1367                 /* XXX could we merge code with following builtin case,
1368                  * by creating a pseudo builtin that calls run_list_real? */
1369                 rcode = run_list_real(child->group);
1370                 restore_redirects(squirrel);
1371                 return rcode;
1372         } else if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1373                 for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
1374                 if (i!=0 && child->argv[i]==NULL) {
1375                         /* assignments, but no command: set the local environment */
1376                         for (i=0; child->argv[i]!=NULL; i++) {
1377
1378                                 /* Ok, this case is tricky.  We have to decide if this is a
1379                                  * local variable, or an already exported variable.  If it is
1380                                  * already exported, we have to export the new value.  If it is
1381                                  * not exported, we need only set this as a local variable.
1382                                  * This junk is all to decide whether or not to export this
1383                                  * variable. */
1384                                 int export_me=0;
1385                                 char *name, *value;
1386                                 name = bb_xstrdup(child->argv[i]);
1387                                 debug_printf("Local environment set: %s\n", name);
1388                                 value = strchr(name, '=');
1389                                 if (value)
1390                                         *value=0;
1391                                 if ( get_local_var(name)) {
1392                                         export_me=1;
1393                                 }
1394                                 free(name);
1395                                 p = insert_var_value(child->argv[i]);
1396                                 set_local_var(p, export_me);
1397                                 if (p != child->argv[i]) free(p);
1398                         }
1399                         return EXIT_SUCCESS;   /* don't worry about errors in set_local_var() yet */
1400                 }
1401                 for (i = 0; is_assignment(child->argv[i]); i++) {
1402                         p = insert_var_value(child->argv[i]);
1403                         putenv(strdup(p));
1404                         if (p != child->argv[i]) {
1405                                 child->sp--;
1406                                 free(p);
1407                         }
1408                 }
1409                 if (child->sp) {
1410                         char * str = NULL;
1411
1412                         str = make_string((child->argv + i));
1413                         parse_string_outer(str, FLAG_EXIT_FROM_LOOP | FLAG_REPARSING);
1414                         free(str);
1415                         return last_return_code;
1416                 }
1417                 for (x = bltins; x->cmd; x++) {
1418                         if (strcmp(child->argv[i], x->cmd) == 0 ) {
1419                                 int squirrel[] = {-1, -1, -1};
1420                                 int rcode;
1421                                 if (x->function == builtin_exec && child->argv[i+1]==NULL) {
1422                                         debug_printf("magic exec\n");
1423                                         setup_redirects(child,NULL);
1424                                         return EXIT_SUCCESS;
1425                                 }
1426                                 debug_printf("builtin inline %s\n", child->argv[0]);
1427                                 /* XXX setup_redirects acts on file descriptors, not FILEs.
1428                                  * This is perfect for work that comes after exec().
1429                                  * Is it really safe for inline use?  Experimentally,
1430                                  * things seem to work with glibc. */
1431                                 setup_redirects(child, squirrel);
1432                                 child->argv+=i;  /* XXX horrible hack */
1433                                 rcode = x->function(child);
1434                                 child->argv-=i;  /* XXX restore hack so free() can work right */
1435                                 restore_redirects(squirrel);
1436                                 return rcode;
1437                         }
1438                 }
1439         }
1440
1441         for (i = 0; i < pi->num_progs; i++) {
1442                 child = & (pi->progs[i]);
1443
1444                 /* pipes are inserted between pairs of commands */
1445                 if ((i + 1) < pi->num_progs) {
1446                         if (pipe(pipefds)<0) bb_perror_msg_and_die("pipe");
1447                         nextout = pipefds[1];
1448                 } else {
1449                         nextout=1;
1450                         pipefds[0] = -1;
1451                 }
1452
1453                 /* XXX test for failed fork()? */
1454 #if !defined(__UCLIBC__) || defined(__UCLIBC_HAS_MMU__)
1455                 if (!(child->pid = fork()))
1456 #else
1457                 if (!(child->pid = vfork()))
1458 #endif
1459                 {
1460                         /* Set the handling for job control signals back to the default.  */
1461                         signal(SIGINT, SIG_DFL);
1462                         signal(SIGQUIT, SIG_DFL);
1463                         signal(SIGTERM, SIG_DFL);
1464                         signal(SIGTSTP, SIG_DFL);
1465                         signal(SIGTTIN, SIG_DFL);
1466                         signal(SIGTTOU, SIG_DFL);
1467                         signal(SIGCHLD, SIG_DFL);
1468
1469                         close_all();
1470
1471                         if (nextin != 0) {
1472                                 dup2(nextin, 0);
1473                                 close(nextin);
1474                         }
1475                         if (nextout != 1) {
1476                                 dup2(nextout, 1);
1477                                 close(nextout);
1478                         }
1479                         if (pipefds[0]!=-1) {
1480                                 close(pipefds[0]);  /* opposite end of our output pipe */
1481                         }
1482
1483                         /* Like bash, explicit redirects override pipes,
1484                          * and the pipe fd is available for dup'ing. */
1485                         setup_redirects(child,NULL);
1486
1487                         if (interactive && pi->followup!=PIPE_BG) {
1488                                 /* If we (the child) win the race, put ourselves in the process
1489                                  * group whose leader is the first process in this pipe. */
1490                                 if (pi->pgrp < 0) {
1491                                         pi->pgrp = getpid();
1492                                 }
1493                                 if (setpgid(0, pi->pgrp) == 0) {
1494                                         tcsetpgrp(2, pi->pgrp);
1495                                 }
1496                         }
1497
1498                         pseudo_exec(child);
1499                 }
1500
1501
1502                 /* put our child in the process group whose leader is the
1503                    first process in this pipe */
1504                 if (pi->pgrp < 0) {
1505                         pi->pgrp = child->pid;
1506                 }
1507                 /* Don't check for errors.  The child may be dead already,
1508                  * in which case setpgid returns error code EACCES. */
1509                 setpgid(child->pid, pi->pgrp);
1510
1511                 if (nextin != 0)
1512                         close(nextin);
1513                 if (nextout != 1)
1514                         close(nextout);
1515
1516                 /* If there isn't another process, nextin is garbage
1517                    but it doesn't matter */
1518                 nextin = pipefds[0];
1519         }
1520         return -1;
1521 }
1522
1523 static int run_list_real(struct pipe *pi)
1524 {
1525         char *save_name = NULL;
1526         char **list = NULL;
1527         char **save_list = NULL;
1528         struct pipe *rpipe;
1529         int flag_rep = 0;
1530         int save_num_progs;
1531         int rcode=0, flag_skip=1;
1532         int flag_restore = 0;
1533         int if_code=0, next_if_code=0;  /* need double-buffer to handle elif */
1534         reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1535         /* check syntax for "for" */
1536         for (rpipe = pi; rpipe; rpipe = rpipe->next) {
1537                 if ((rpipe->r_mode == RES_IN ||
1538                     rpipe->r_mode == RES_FOR) &&
1539                     (rpipe->next == NULL)) {
1540                                 syntax();
1541                                 return 1;
1542                 }
1543                 if ((rpipe->r_mode == RES_IN &&
1544                         (rpipe->next->r_mode == RES_IN &&
1545                         rpipe->next->progs->argv != NULL))||
1546                         (rpipe->r_mode == RES_FOR &&
1547                         rpipe->next->r_mode != RES_IN)) {
1548                                 syntax();
1549                                 return 1;
1550                 }
1551         }
1552         for (; pi; pi = (flag_restore != 0) ? rpipe : pi->next) {
1553                 if (pi->r_mode == RES_WHILE || pi->r_mode == RES_UNTIL ||
1554                         pi->r_mode == RES_FOR) {
1555                                 flag_restore = 0;
1556                                 if (!rpipe) {
1557                                         flag_rep = 0;
1558                                         rpipe = pi;
1559                                 }
1560                 }
1561                 rmode = pi->r_mode;
1562                 debug_printf("rmode=%d  if_code=%d  next_if_code=%d skip_more=%d\n", rmode, if_code, next_if_code, skip_more_in_this_rmode);
1563                 if (rmode == skip_more_in_this_rmode && flag_skip) {
1564                         if (pi->followup == PIPE_SEQ) flag_skip=0;
1565                         continue;
1566                 }
1567                 flag_skip = 1;
1568                 skip_more_in_this_rmode = RES_XXXX;
1569                 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1570                 if (rmode == RES_THEN &&  if_code) continue;
1571                 if (rmode == RES_ELSE && !if_code) continue;
1572                 if (rmode == RES_ELIF && !if_code) continue;
1573                 if (rmode == RES_FOR && pi->num_progs) {
1574                         if (!list) {
1575                                 /* if no variable values after "in" we skip "for" */
1576                                 if (!pi->next->progs->argv) continue;
1577                                 /* create list of variable values */
1578                                 list = make_list_in(pi->next->progs->argv,
1579                                         pi->progs->argv[0]);
1580                                 save_list = list;
1581                                 save_name = pi->progs->argv[0];
1582                                 pi->progs->argv[0] = NULL;
1583                                 flag_rep = 1;
1584                         }
1585                         if (!(*list)) {
1586                                 free(pi->progs->argv[0]);
1587                                 free(save_list);
1588                                 list = NULL;
1589                                 flag_rep = 0;
1590                                 pi->progs->argv[0] = save_name;
1591                                 pi->progs->glob_result.gl_pathv[0] =
1592                                         pi->progs->argv[0];
1593                                 continue;
1594                         } else {
1595                                 /* insert new value from list for variable */
1596                                 if (pi->progs->argv[0])
1597                                         free(pi->progs->argv[0]);
1598                                 pi->progs->argv[0] = *list++;
1599                                 pi->progs->glob_result.gl_pathv[0] =
1600                                         pi->progs->argv[0];
1601                         }
1602                 }
1603                 if (rmode == RES_IN) continue;
1604                 if (rmode == RES_DO) {
1605                         if (!flag_rep) continue;
1606                 }
1607                 if ((rmode == RES_DONE)) {
1608                         if (flag_rep) {
1609                                 flag_restore = 1;
1610                         } else {
1611                                 rpipe = NULL;
1612                         }
1613                 }
1614                 if (pi->num_progs == 0) continue;
1615                 save_num_progs = pi->num_progs; /* save number of programs */
1616                 rcode = run_pipe_real(pi);
1617                 debug_printf("run_pipe_real returned %d\n",rcode);
1618                 if (rcode!=-1) {
1619                         /* We only ran a builtin: rcode was set by the return value
1620                          * of run_pipe_real(), and we don't need to wait for anything. */
1621                 } else if (pi->followup==PIPE_BG) {
1622                         /* XXX check bash's behavior with nontrivial pipes */
1623                         /* XXX compute jobid */
1624                         /* XXX what does bash do with attempts to background builtins? */
1625                         insert_bg_job(pi);
1626                         rcode = EXIT_SUCCESS;
1627                 } else {
1628                         if (interactive) {
1629                                 /* move the new process group into the foreground */
1630                                 if (tcsetpgrp(shell_terminal, pi->pgrp) && errno != ENOTTY)
1631                                         bb_perror_msg("tcsetpgrp-3");
1632                                 rcode = checkjobs(pi);
1633                                 /* move the shell to the foreground */
1634                                 if (tcsetpgrp(shell_terminal, getpgid(0)) && errno != ENOTTY)
1635                                         bb_perror_msg("tcsetpgrp-4");
1636                         } else {
1637                                 rcode = checkjobs(pi);
1638                         }
1639                         debug_printf("checkjobs returned %d\n",rcode);
1640                 }
1641                 last_return_code=rcode;
1642                 pi->num_progs = save_num_progs; /* restore number of programs */
1643                 if ( rmode == RES_IF || rmode == RES_ELIF )
1644                         next_if_code=rcode;  /* can be overwritten a number of times */
1645                 if (rmode == RES_WHILE)
1646                         flag_rep = !last_return_code;
1647                 if (rmode == RES_UNTIL)
1648                         flag_rep = last_return_code;
1649                 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1650                      (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1651                         skip_more_in_this_rmode=rmode;
1652                 checkjobs(NULL);
1653         }
1654         return rcode;
1655 }
1656
1657 /* broken, of course, but OK for testing */
1658 static char *indenter(int i)
1659 {
1660         static char blanks[]="                                    ";
1661         return &blanks[sizeof(blanks)-i-1];
1662 }
1663
1664 /* return code is the exit status of the pipe */
1665 static int free_pipe(struct pipe *pi, int indent)
1666 {
1667         char **p;
1668         struct child_prog *child;
1669         struct redir_struct *r, *rnext;
1670         int a, i, ret_code=0;
1671         char *ind = indenter(indent);
1672
1673         if (pi->stopped_progs > 0)
1674                 return ret_code;
1675         final_printf("%s run pipe: (pid %d)\n",ind,getpid());
1676         for (i=0; i<pi->num_progs; i++) {
1677                 child = &pi->progs[i];
1678                 final_printf("%s  command %d:\n",ind,i);
1679                 if (child->argv) {
1680                         for (a=0,p=child->argv; *p; a++,p++) {
1681                                 final_printf("%s   argv[%d] = %s\n",ind,a,*p);
1682                         }
1683                         globfree(&child->glob_result);
1684                         child->argv=NULL;
1685                 } else if (child->group) {
1686                         final_printf("%s   begin group (subshell:%d)\n",ind, child->subshell);
1687                         ret_code = free_pipe_list(child->group,indent+3);
1688                         final_printf("%s   end group\n",ind);
1689                 } else {
1690                         final_printf("%s   (nil)\n",ind);
1691                 }
1692                 for (r=child->redirects; r; r=rnext) {
1693                         final_printf("%s   redirect %d%s", ind, r->fd, redir_table[r->type].descrip);
1694                         if (r->dup == -1) {
1695                                 /* guard against the case >$FOO, where foo is unset or blank */
1696                                 if (r->word.gl_pathv) {
1697                                         final_printf(" %s\n", *r->word.gl_pathv);
1698                                         globfree(&r->word);
1699                                 }
1700                         } else {
1701                                 final_printf("&%d\n", r->dup);
1702                         }
1703                         rnext=r->next;
1704                         free(r);
1705                 }
1706                 child->redirects=NULL;
1707         }
1708         free(pi->progs);   /* children are an array, they get freed all at once */
1709         pi->progs=NULL;
1710         return ret_code;
1711 }
1712
1713 static int free_pipe_list(struct pipe *head, int indent)
1714 {
1715         int rcode=0;   /* if list has no members */
1716         struct pipe *pi, *next;
1717         char *ind = indenter(indent);
1718         for (pi=head; pi; pi=next) {
1719                 final_printf("%s pipe reserved mode %d\n", ind, pi->r_mode);
1720                 rcode = free_pipe(pi, indent);
1721                 final_printf("%s pipe followup code %d\n", ind, pi->followup);
1722                 next=pi->next;
1723                 pi->next=NULL;
1724                 free(pi);
1725         }
1726         return rcode;
1727 }
1728
1729 /* Select which version we will use */
1730 static int run_list(struct pipe *pi)
1731 {
1732         int rcode=0;
1733         if (fake_mode==0) {
1734                 rcode = run_list_real(pi);
1735         }
1736         /* free_pipe_list has the side effect of clearing memory
1737          * In the long run that function can be merged with run_list_real,
1738          * but doing that now would hobble the debugging effort. */
1739         free_pipe_list(pi,0);
1740         return rcode;
1741 }
1742
1743 /* The API for glob is arguably broken.  This routine pushes a non-matching
1744  * string into the output structure, removing non-backslashed backslashes.
1745  * If someone can prove me wrong, by performing this function within the
1746  * original glob(3) api, feel free to rewrite this routine into oblivion.
1747  * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1748  * XXX broken if the last character is '\\', check that before calling.
1749  */
1750 static int globhack(const char *src, int flags, glob_t *pglob)
1751 {
1752         int cnt=0, pathc;
1753         const char *s;
1754         char *dest;
1755         for (cnt=1, s=src; s && *s; s++) {
1756                 if (*s == '\\') s++;
1757                 cnt++;
1758         }
1759         dest = malloc(cnt);
1760         if (!dest) return GLOB_NOSPACE;
1761         if (!(flags & GLOB_APPEND)) {
1762                 pglob->gl_pathv=NULL;
1763                 pglob->gl_pathc=0;
1764                 pglob->gl_offs=0;
1765                 pglob->gl_offs=0;
1766         }
1767         pathc = ++pglob->gl_pathc;
1768         pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1769         if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1770         pglob->gl_pathv[pathc-1]=dest;
1771         pglob->gl_pathv[pathc]=NULL;
1772         for (s=src; s && *s; s++, dest++) {
1773                 if (*s == '\\') s++;
1774                 *dest = *s;
1775         }
1776         *dest='\0';
1777         return 0;
1778 }
1779
1780 /* XXX broken if the last character is '\\', check that before calling */
1781 static int glob_needed(const char *s)
1782 {
1783         for (; *s; s++) {
1784                 if (*s == '\\') s++;
1785                 if (strchr("*[?",*s)) return 1;
1786         }
1787         return 0;
1788 }
1789
1790 #if 0
1791 static void globprint(glob_t *pglob)
1792 {
1793         int i;
1794         debug_printf("glob_t at %p:\n", pglob);
1795         debug_printf("  gl_pathc=%d  gl_pathv=%p  gl_offs=%d  gl_flags=%d\n",
1796                 pglob->gl_pathc, pglob->gl_pathv, pglob->gl_offs, pglob->gl_flags);
1797         for (i=0; i<pglob->gl_pathc; i++)
1798                 debug_printf("pglob->gl_pathv[%d] = %p = %s\n", i,
1799                         pglob->gl_pathv[i], pglob->gl_pathv[i]);
1800 }
1801 #endif
1802
1803 static int xglob(o_string *dest, int flags, glob_t *pglob)
1804 {
1805         int gr;
1806
1807         /* short-circuit for null word */
1808         /* we can code this better when the debug_printf's are gone */
1809         if (dest->length == 0) {
1810                 if (dest->nonnull) {
1811                         /* bash man page calls this an "explicit" null */
1812                         gr = globhack(dest->data, flags, pglob);
1813                         debug_printf("globhack returned %d\n",gr);
1814                 } else {
1815                         return 0;
1816                 }
1817         } else if (glob_needed(dest->data)) {
1818                 gr = glob(dest->data, flags, NULL, pglob);
1819                 debug_printf("glob returned %d\n",gr);
1820                 if (gr == GLOB_NOMATCH) {
1821                         /* quote removal, or more accurately, backslash removal */
1822                         gr = globhack(dest->data, flags, pglob);
1823                         debug_printf("globhack returned %d\n",gr);
1824                 }
1825         } else {
1826                 gr = globhack(dest->data, flags, pglob);
1827                 debug_printf("globhack returned %d\n",gr);
1828         }
1829         if (gr == GLOB_NOSPACE)
1830                 bb_error_msg_and_die("out of memory during glob");
1831         if (gr != 0) { /* GLOB_ABORTED ? */
1832                 bb_error_msg("glob(3) error %d",gr);
1833         }
1834         /* globprint(glob_target); */
1835         return gr;
1836 }
1837
1838 /* This is used to get/check local shell variables */
1839 static char *get_local_var(const char *s)
1840 {
1841         struct variables *cur;
1842
1843         if (!s)
1844                 return NULL;
1845         for (cur = top_vars; cur; cur=cur->next)
1846                 if(strcmp(cur->name, s)==0)
1847                         return cur->value;
1848         return NULL;
1849 }
1850
1851 /* This is used to set local shell variables
1852    flg_export==0 if only local (not exporting) variable
1853    flg_export==1 if "new" exporting environ
1854    flg_export>1  if current startup environ (not call putenv()) */
1855 static int set_local_var(const char *s, int flg_export)
1856 {
1857         char *name, *value;
1858         int result=0;
1859         struct variables *cur;
1860
1861         name=strdup(s);
1862
1863         /* Assume when we enter this function that we are already in
1864          * NAME=VALUE format.  So the first order of business is to
1865          * split 's' on the '=' into 'name' and 'value' */
1866         value = strchr(name, '=');
1867         if (value==0 && ++value==0) {
1868                 free(name);
1869                 return -1;
1870         }
1871         *value++ = 0;
1872
1873         for(cur = top_vars; cur; cur = cur->next) {
1874                 if(strcmp(cur->name, name)==0)
1875                         break;
1876         }
1877
1878         if(cur) {
1879                 if(strcmp(cur->value, value)==0) {
1880                         if(flg_export>0 && cur->flg_export==0)
1881                                 cur->flg_export=flg_export;
1882                         else
1883                                 result++;
1884                 } else {
1885                         if(cur->flg_read_only) {
1886                                 bb_error_msg("%s: readonly variable", name);
1887                                 result = -1;
1888                         } else {
1889                                 if(flg_export>0 || cur->flg_export>1)
1890                                         cur->flg_export=1;
1891                                 free(cur->value);
1892
1893                                 cur->value = strdup(value);
1894                         }
1895                 }
1896         } else {
1897                 cur = malloc(sizeof(struct variables));
1898                 if(!cur) {
1899                         result = -1;
1900                 } else {
1901                         cur->name = strdup(name);
1902                         if(cur->name == 0) {
1903                                 free(cur);
1904                                 result = -1;
1905                         } else {
1906                                 struct variables *bottom = top_vars;
1907                                 cur->value = strdup(value);
1908                                 cur->next = 0;
1909                                 cur->flg_export = flg_export;
1910                                 cur->flg_read_only = 0;
1911                                 while(bottom->next) bottom=bottom->next;
1912                                 bottom->next = cur;
1913                         }
1914                 }
1915         }
1916
1917         if(result==0 && cur->flg_export==1) {
1918                 *(value-1) = '=';
1919                 result = putenv(name);
1920         } else {
1921                 free(name);
1922                 if(result>0)            /* equivalent to previous set */
1923                         result = 0;
1924         }
1925         return result;
1926 }
1927
1928 static void unset_local_var(const char *name)
1929 {
1930         struct variables *cur;
1931
1932         if (name) {
1933                 for (cur = top_vars; cur; cur=cur->next) {
1934                         if(strcmp(cur->name, name)==0)
1935                                 break;
1936                 }
1937                 if(cur!=0) {
1938                         struct variables *next = top_vars;
1939                         if(cur->flg_read_only) {
1940                                 bb_error_msg("%s: readonly variable", name);
1941                                 return;
1942                         } else {
1943                                 if(cur->flg_export)
1944                                         unsetenv(cur->name);
1945                                 free(cur->name);
1946                                 free(cur->value);
1947                                 while (next->next != cur)
1948                                         next = next->next;
1949                                 next->next = cur->next;
1950                         }
1951                         free(cur);
1952                 }
1953         }
1954 }
1955
1956 static int is_assignment(const char *s)
1957 {
1958         if (s==NULL || !isalpha(*s)) return 0;
1959         ++s;
1960         while(isalnum(*s) || *s=='_') ++s;
1961         return *s=='=';
1962 }
1963
1964 /* the src parameter allows us to peek forward to a possible &n syntax
1965  * for file descriptor duplication, e.g., "2>&1".
1966  * Return code is 0 normally, 1 if a syntax error is detected in src.
1967  * Resource errors (in xmalloc) cause the process to exit */
1968 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1969         struct in_str *input)
1970 {
1971         struct child_prog *child=ctx->child;
1972         struct redir_struct *redir = child->redirects;
1973         struct redir_struct *last_redir=NULL;
1974
1975         /* Create a new redir_struct and drop it onto the end of the linked list */
1976         while(redir) {
1977                 last_redir=redir;
1978                 redir=redir->next;
1979         }
1980         redir = xmalloc(sizeof(struct redir_struct));
1981         redir->next=NULL;
1982         redir->word.gl_pathv=NULL;
1983         if (last_redir) {
1984                 last_redir->next=redir;
1985         } else {
1986                 child->redirects=redir;
1987         }
1988
1989         redir->type=style;
1990         redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1991
1992         debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1993
1994         /* Check for a '2>&1' type redirect */
1995         redir->dup = redirect_dup_num(input);
1996         if (redir->dup == -2) return 1;  /* syntax error */
1997         if (redir->dup != -1) {
1998                 /* Erik had a check here that the file descriptor in question
1999                  * is legit; I postpone that to "run time"
2000                  * A "-" representation of "close me" shows up as a -3 here */
2001                 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
2002         } else {
2003                 /* We do _not_ try to open the file that src points to,
2004                  * since we need to return and let src be expanded first.
2005                  * Set ctx->pending_redirect, so we know what to do at the
2006                  * end of the next parsed word.
2007                  */
2008                 ctx->pending_redirect = redir;
2009         }
2010         return 0;
2011 }
2012
2013 struct pipe *new_pipe(void) {
2014         struct pipe *pi;
2015         pi = xmalloc(sizeof(struct pipe));
2016         pi->num_progs = 0;
2017         pi->progs = NULL;
2018         pi->next = NULL;
2019         pi->followup = 0;  /* invalid */
2020         return pi;
2021 }
2022
2023 static void initialize_context(struct p_context *ctx)
2024 {
2025         ctx->pipe=NULL;
2026         ctx->pending_redirect=NULL;
2027         ctx->child=NULL;
2028         ctx->list_head=new_pipe();
2029         ctx->pipe=ctx->list_head;
2030         ctx->w=RES_NONE;
2031         ctx->stack=NULL;
2032         ctx->old_flag=0;
2033         done_command(ctx);   /* creates the memory for working child */
2034 }
2035
2036 /* normal return is 0
2037  * if a reserved word is found, and processed, return 1
2038  * should handle if, then, elif, else, fi, for, while, until, do, done.
2039  * case, function, and select are obnoxious, save those for later.
2040  */
2041 int reserved_word(o_string *dest, struct p_context *ctx)
2042 {
2043         struct reserved_combo {
2044                 char *literal;
2045                 int code;
2046                 long flag;
2047         };
2048         /* Mostly a list of accepted follow-up reserved words.
2049          * FLAG_END means we are done with the sequence, and are ready
2050          * to turn the compound list into a command.
2051          * FLAG_START means the word must start a new compound list.
2052          */
2053         static struct reserved_combo reserved_list[] = {
2054                 { "if",    RES_IF,    FLAG_THEN | FLAG_START },
2055                 { "then",  RES_THEN,  FLAG_ELIF | FLAG_ELSE | FLAG_FI },
2056                 { "elif",  RES_ELIF,  FLAG_THEN },
2057                 { "else",  RES_ELSE,  FLAG_FI   },
2058                 { "fi",    RES_FI,    FLAG_END  },
2059                 { "for",   RES_FOR,   FLAG_IN   | FLAG_START },
2060                 { "while", RES_WHILE, FLAG_DO   | FLAG_START },
2061                 { "until", RES_UNTIL, FLAG_DO   | FLAG_START },
2062                 { "in",    RES_IN,    FLAG_DO   },
2063                 { "do",    RES_DO,    FLAG_DONE },
2064                 { "done",  RES_DONE,  FLAG_END  }
2065         };
2066         struct reserved_combo *r;
2067         for (r=reserved_list;
2068 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
2069                 r<reserved_list+NRES; r++) {
2070                 if (strcmp(dest->data, r->literal) == 0) {
2071                         debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
2072                         if (r->flag & FLAG_START) {
2073                                 struct p_context *new = xmalloc(sizeof(struct p_context));
2074                                 debug_printf("push stack\n");
2075                                 if (ctx->w == RES_IN || ctx->w == RES_FOR) {
2076                                         syntax();
2077                                         free(new);
2078                                         ctx->w = RES_SNTX;
2079                                         b_reset(dest);
2080                                         return 1;
2081                                 }
2082                                 *new = *ctx;   /* physical copy */
2083                                 initialize_context(ctx);
2084                                 ctx->stack=new;
2085                         } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
2086                                 syntax();
2087                                 ctx->w = RES_SNTX;
2088                                 b_reset(dest);
2089                                 return 1;
2090                         }
2091                         ctx->w=r->code;
2092                         ctx->old_flag = r->flag;
2093                         if (ctx->old_flag & FLAG_END) {
2094                                 struct p_context *old;
2095                                 debug_printf("pop stack\n");
2096                                 done_pipe(ctx,PIPE_SEQ);
2097                                 old = ctx->stack;
2098                                 old->child->group = ctx->list_head;
2099                                 old->child->subshell = 0;
2100                                 *ctx = *old;   /* physical copy */
2101                                 free(old);
2102                         }
2103                         b_reset (dest);
2104                         return 1;
2105                 }
2106         }
2107         return 0;
2108 }
2109
2110 /* normal return is 0.
2111  * Syntax or xglob errors return 1. */
2112 static int done_word(o_string *dest, struct p_context *ctx)
2113 {
2114         struct child_prog *child=ctx->child;
2115         glob_t *glob_target;
2116         int gr, flags = 0;
2117
2118         debug_printf("done_word: %s %p\n", dest->data, child);
2119         if (dest->length == 0 && !dest->nonnull) {
2120                 debug_printf("  true null, ignored\n");
2121                 return 0;
2122         }
2123         if (ctx->pending_redirect) {
2124                 glob_target = &ctx->pending_redirect->word;
2125         } else {
2126                 if (child->group) {
2127                         syntax();
2128                         return 1;  /* syntax error, groups and arglists don't mix */
2129                 }
2130                 if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) {
2131                         debug_printf("checking %s for reserved-ness\n",dest->data);
2132                         if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
2133                 }
2134                 glob_target = &child->glob_result;
2135                 if (child->argv) flags |= GLOB_APPEND;
2136         }
2137         gr = xglob(dest, flags, glob_target);
2138         if (gr != 0) return 1;
2139
2140         b_reset(dest);
2141         if (ctx->pending_redirect) {
2142                 ctx->pending_redirect=NULL;
2143                 if (glob_target->gl_pathc != 1) {
2144                         bb_error_msg("ambiguous redirect");
2145                         return 1;
2146                 }
2147         } else {
2148                 child->argv = glob_target->gl_pathv;
2149         }
2150         if (ctx->w == RES_FOR) {
2151                 done_word(dest,ctx);
2152                 done_pipe(ctx,PIPE_SEQ);
2153         }
2154         return 0;
2155 }
2156
2157 /* The only possible error here is out of memory, in which case
2158  * xmalloc exits. */
2159 static int done_command(struct p_context *ctx)
2160 {
2161         /* The child is really already in the pipe structure, so
2162          * advance the pipe counter and make a new, null child.
2163          * Only real trickiness here is that the uncommitted
2164          * child structure, to which ctx->child points, is not
2165          * counted in pi->num_progs. */
2166         struct pipe *pi=ctx->pipe;
2167         struct child_prog *prog=ctx->child;
2168
2169         if (prog && prog->group == NULL
2170                  && prog->argv == NULL
2171                  && prog->redirects == NULL) {
2172                 debug_printf("done_command: skipping null command\n");
2173                 return 0;
2174         } else if (prog) {
2175                 pi->num_progs++;
2176                 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
2177         } else {
2178                 debug_printf("done_command: initializing\n");
2179         }
2180         pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
2181
2182         prog = pi->progs + pi->num_progs;
2183         prog->redirects = NULL;
2184         prog->argv = NULL;
2185         prog->is_stopped = 0;
2186         prog->group = NULL;
2187         prog->glob_result.gl_pathv = NULL;
2188         prog->family = pi;
2189         prog->sp = 0;
2190         ctx->child = prog;
2191         prog->type = ctx->type;
2192
2193         /* but ctx->pipe and ctx->list_head remain unchanged */
2194         return 0;
2195 }
2196
2197 static int done_pipe(struct p_context *ctx, pipe_style type)
2198 {
2199         struct pipe *new_p;
2200         done_command(ctx);  /* implicit closure of previous command */
2201         debug_printf("done_pipe, type %d\n", type);
2202         ctx->pipe->followup = type;
2203         ctx->pipe->r_mode = ctx->w;
2204         new_p=new_pipe();
2205         ctx->pipe->next = new_p;
2206         ctx->pipe = new_p;
2207         ctx->child = NULL;
2208         done_command(ctx);  /* set up new pipe to accept commands */
2209         return 0;
2210 }
2211
2212 /* peek ahead in the in_str to find out if we have a "&n" construct,
2213  * as in "2>&1", that represents duplicating a file descriptor.
2214  * returns either -2 (syntax error), -1 (no &), or the number found.
2215  */
2216 static int redirect_dup_num(struct in_str *input)
2217 {
2218         int ch, d=0, ok=0;
2219         ch = b_peek(input);
2220         if (ch != '&') return -1;
2221
2222         b_getch(input);  /* get the & */
2223         ch=b_peek(input);
2224         if (ch == '-') {
2225                 b_getch(input);
2226                 return -3;  /* "-" represents "close me" */
2227         }
2228         while (isdigit(ch)) {
2229                 d = d*10+(ch-'0');
2230                 ok=1;
2231                 b_getch(input);
2232                 ch = b_peek(input);
2233         }
2234         if (ok) return d;
2235
2236         bb_error_msg("ambiguous redirect");
2237         return -2;
2238 }
2239
2240 /* If a redirect is immediately preceded by a number, that number is
2241  * supposed to tell which file descriptor to redirect.  This routine
2242  * looks for such preceding numbers.  In an ideal world this routine
2243  * needs to handle all the following classes of redirects...
2244  *     echo 2>foo     # redirects fd  2 to file "foo", nothing passed to echo
2245  *     echo 49>foo    # redirects fd 49 to file "foo", nothing passed to echo
2246  *     echo -2>foo    # redirects fd  1 to file "foo",    "-2" passed to echo
2247  *     echo 49x>foo   # redirects fd  1 to file "foo",   "49x" passed to echo
2248  * A -1 output from this program means no valid number was found, so the
2249  * caller should use the appropriate default for this redirection.
2250  */
2251 static int redirect_opt_num(o_string *o)
2252 {
2253         int num;
2254
2255         if (o->length==0) return -1;
2256         for(num=0; num<o->length; num++) {
2257                 if (!isdigit(*(o->data+num))) {
2258                         return -1;
2259                 }
2260         }
2261         /* reuse num (and save an int) */
2262         num=atoi(o->data);
2263         b_reset(o);
2264         return num;
2265 }
2266
2267 FILE *generate_stream_from_list(struct pipe *head)
2268 {
2269         FILE *pf;
2270 #if 1
2271         int pid, channel[2];
2272         if (pipe(channel)<0) bb_perror_msg_and_die("pipe");
2273 #if !defined(__UCLIBC__) || defined(__UCLIBC_HAS_MMU__)
2274         pid=fork();
2275 #else
2276         pid=vfork();
2277 #endif
2278         if (pid<0) {
2279                 bb_perror_msg_and_die("fork");
2280         } else if (pid==0) {
2281                 close(channel[0]);
2282                 if (channel[1] != 1) {
2283                         dup2(channel[1],1);
2284                         close(channel[1]);
2285                 }
2286 #if 0
2287 #define SURROGATE "surrogate response"
2288                 write(1,SURROGATE,sizeof(SURROGATE));
2289                 _exit(run_list(head));
2290 #else
2291                 _exit(run_list_real(head));   /* leaks memory */
2292 #endif
2293         }
2294         debug_printf("forked child %d\n",pid);
2295         close(channel[1]);
2296         pf = fdopen(channel[0],"r");
2297         debug_printf("pipe on FILE *%p\n",pf);
2298 #else
2299         free_pipe_list(head,0);
2300         pf=popen("echo surrogate response","r");
2301         debug_printf("started fake pipe on FILE *%p\n",pf);
2302 #endif
2303         return pf;
2304 }
2305
2306 /* this version hacked for testing purposes */
2307 /* return code is exit status of the process that is run. */
2308 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2309 {
2310         int retcode;
2311         o_string result=NULL_O_STRING;
2312         struct p_context inner;
2313         FILE *p;
2314         struct in_str pipe_str;
2315         initialize_context(&inner);
2316
2317         /* recursion to generate command */
2318         retcode = parse_stream(&result, &inner, input, subst_end);
2319         if (retcode != 0) return retcode;  /* syntax error or EOF */
2320         done_word(&result, &inner);
2321         done_pipe(&inner, PIPE_SEQ);
2322         b_free(&result);
2323
2324         p=generate_stream_from_list(inner.list_head);
2325         if (p==NULL) return 1;
2326         mark_open(fileno(p));
2327         setup_file_in_str(&pipe_str, p);
2328
2329         /* now send results of command back into original context */
2330         retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2331         /* XXX In case of a syntax error, should we try to kill the child?
2332          * That would be tough to do right, so just read until EOF. */
2333         if (retcode == 1) {
2334                 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
2335         }
2336
2337         debug_printf("done reading from pipe, pclose()ing\n");
2338         /* This is the step that wait()s for the child.  Should be pretty
2339          * safe, since we just read an EOF from its stdout.  We could try
2340          * to better, by using wait(), and keeping track of background jobs
2341          * at the same time.  That would be a lot of work, and contrary
2342          * to the KISS philosophy of this program. */
2343         mark_closed(fileno(p));
2344         retcode=pclose(p);
2345         free_pipe_list(inner.list_head,0);
2346         debug_printf("pclosed, retcode=%d\n",retcode);
2347         /* XXX this process fails to trim a single trailing newline */
2348         return retcode;
2349 }
2350
2351 static int parse_group(o_string *dest, struct p_context *ctx,
2352         struct in_str *input, int ch)
2353 {
2354         int rcode, endch=0;
2355         struct p_context sub;
2356         struct child_prog *child = ctx->child;
2357         if (child->argv) {
2358                 syntax();
2359                 return 1;  /* syntax error, groups and arglists don't mix */
2360         }
2361         initialize_context(&sub);
2362         switch(ch) {
2363                 case '(': endch=')'; child->subshell=1; break;
2364                 case '{': endch='}'; break;
2365                 default: syntax();   /* really logic error */
2366         }
2367         rcode=parse_stream(dest,&sub,input,endch);
2368         done_word(dest,&sub); /* finish off the final word in the subcontext */
2369         done_pipe(&sub, PIPE_SEQ);  /* and the final command there, too */
2370         child->group = sub.list_head;
2371         return rcode;
2372         /* child remains "open", available for possible redirects */
2373 }
2374
2375 /* basically useful version until someone wants to get fancier,
2376  * see the bash man page under "Parameter Expansion" */
2377 static char *lookup_param(char *src)
2378 {
2379         char *p=NULL;
2380         if (src) {
2381                 p = getenv(src);
2382                 if (!p)
2383                         p = get_local_var(src);
2384         }
2385         return p;
2386 }
2387
2388 /* return code: 0 for OK, 1 for syntax error */
2389 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2390 {
2391         int i, advance=0;
2392         char sep[]=" ";
2393         int ch = input->peek(input);  /* first character after the $ */
2394         debug_printf("handle_dollar: ch=%c\n",ch);
2395         if (isalpha(ch)) {
2396                 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2397                 ctx->child->sp++;
2398                 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
2399                         b_getch(input);
2400                         b_addchr(dest,ch);
2401                 }
2402                 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2403         } else if (isdigit(ch)) {
2404                 i = ch-'0';  /* XXX is $0 special? */
2405                 if (i<global_argc) {
2406                         parse_string(dest, ctx, global_argv[i]); /* recursion */
2407                 }
2408                 advance = 1;
2409         } else switch (ch) {
2410                 case '$':
2411                         b_adduint(dest,getpid());
2412                         advance = 1;
2413                         break;
2414                 case '!':
2415                         if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2416                         advance = 1;
2417                         break;
2418                 case '?':
2419                         b_adduint(dest,last_return_code);
2420                         advance = 1;
2421                         break;
2422                 case '#':
2423                         b_adduint(dest,global_argc ? global_argc-1 : 0);
2424                         advance = 1;
2425                         break;
2426                 case '{':
2427                         b_addchr(dest, SPECIAL_VAR_SYMBOL);
2428                         ctx->child->sp++;
2429                         b_getch(input);
2430                         /* XXX maybe someone will try to escape the '}' */
2431                         while(ch=b_getch(input),ch!=EOF && ch!='}') {
2432                                 b_addchr(dest,ch);
2433                         }
2434                         if (ch != '}') {
2435                                 syntax();
2436                                 return 1;
2437                         }
2438                         b_addchr(dest, SPECIAL_VAR_SYMBOL);
2439                         break;
2440                 case '(':
2441                         b_getch(input);
2442                         process_command_subs(dest, ctx, input, ')');
2443                         break;
2444                 case '*':
2445                         sep[0]=ifs[0];
2446                         for (i=1; i<global_argc; i++) {
2447                                 parse_string(dest, ctx, global_argv[i]);
2448                                 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2449                         }
2450                         break;
2451                 case '@':
2452                 case '-':
2453                 case '_':
2454                         /* still unhandled, but should be eventually */
2455                         bb_error_msg("unhandled syntax: $%c",ch);
2456                         return 1;
2457                         break;
2458                 default:
2459                         b_addqchr(dest,'$',dest->quote);
2460         }
2461         /* Eat the character if the flag was set.  If the compiler
2462          * is smart enough, we could substitute "b_getch(input);"
2463          * for all the "advance = 1;" above, and also end up with
2464          * a nice size-optimized program.  Hah!  That'll be the day.
2465          */
2466         if (advance) b_getch(input);
2467         return 0;
2468 }
2469
2470 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2471 {
2472         struct in_str foo;
2473         setup_string_in_str(&foo, src);
2474         return parse_stream(dest, ctx, &foo, '\0');
2475 }
2476
2477 /* return code is 0 for normal exit, 1 for syntax error */
2478 int parse_stream(o_string *dest, struct p_context *ctx,
2479         struct in_str *input, int end_trigger)
2480 {
2481         unsigned int ch, m;
2482         int redir_fd;
2483         redir_type redir_style;
2484         int next;
2485
2486         /* Only double-quote state is handled in the state variable dest->quote.
2487          * A single-quote triggers a bypass of the main loop until its mate is
2488          * found.  When recursing, quote state is passed in via dest->quote. */
2489
2490         debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2491         while ((ch=b_getch(input))!=EOF) {
2492                 m = map[ch];
2493                 next = (ch == '\n') ? 0 : b_peek(input);
2494                 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2495                         ch,ch,m,dest->quote);
2496                 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2497                         b_addqchr(dest, ch, dest->quote);
2498                 } else {
2499                         if (m==2) {  /* unquoted IFS */
2500                                 if (done_word(dest, ctx)) {
2501                                         return 1;
2502                                 }
2503                                 /* If we aren't performing a substitution, treat a newline as a
2504                                  * command separator.  */
2505                                 if (end_trigger != '\0' && ch=='\n')
2506                                         done_pipe(ctx,PIPE_SEQ);
2507                         }
2508                         if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2509                                 debug_printf("leaving parse_stream (triggered)\n");
2510                                 return 0;
2511                         }
2512 #if 0
2513                         if (ch=='\n') {
2514                                 /* Yahoo!  Time to run with it! */
2515                                 done_pipe(ctx,PIPE_SEQ);
2516                                 run_list(ctx->list_head);
2517                                 initialize_context(ctx);
2518                         }
2519 #endif
2520                         if (m!=2) switch (ch) {
2521                 case '#':
2522                         if (dest->length == 0 && !dest->quote) {
2523                                 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2524                         } else {
2525                                 b_addqchr(dest, ch, dest->quote);
2526                         }
2527                         break;
2528                 case '\\':
2529                         if (next == EOF) {
2530                                 syntax();
2531                                 return 1;
2532                         }
2533                         b_addqchr(dest, '\\', dest->quote);
2534                         b_addqchr(dest, b_getch(input), dest->quote);
2535                         break;
2536                 case '$':
2537                         if (handle_dollar(dest, ctx, input)!=0) return 1;
2538                         break;
2539                 case '\'':
2540                         dest->nonnull = 1;
2541                         while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2542                                 b_addchr(dest,ch);
2543                         }
2544                         if (ch==EOF) {
2545                                 syntax();
2546                                 return 1;
2547                         }
2548                         break;
2549                 case '"':
2550                         dest->nonnull = 1;
2551                         dest->quote = !dest->quote;
2552                         break;
2553                 case '`':
2554                         process_command_subs(dest, ctx, input, '`');
2555                         break;
2556                 case '>':
2557                         redir_fd = redirect_opt_num(dest);
2558                         done_word(dest, ctx);
2559                         redir_style=REDIRECT_OVERWRITE;
2560                         if (next == '>') {
2561                                 redir_style=REDIRECT_APPEND;
2562                                 b_getch(input);
2563                         } else if (next == '(') {
2564                                 syntax();   /* until we support >(list) Process Substitution */
2565                                 return 1;
2566                         }
2567                         setup_redirect(ctx, redir_fd, redir_style, input);
2568                         break;
2569                 case '<':
2570                         redir_fd = redirect_opt_num(dest);
2571                         done_word(dest, ctx);
2572                         redir_style=REDIRECT_INPUT;
2573                         if (next == '<') {
2574                                 redir_style=REDIRECT_HEREIS;
2575                                 b_getch(input);
2576                         } else if (next == '>') {
2577                                 redir_style=REDIRECT_IO;
2578                                 b_getch(input);
2579                         } else if (next == '(') {
2580                                 syntax();   /* until we support <(list) Process Substitution */
2581                                 return 1;
2582                         }
2583                         setup_redirect(ctx, redir_fd, redir_style, input);
2584                         break;
2585                 case ';':
2586                         done_word(dest, ctx);
2587                         done_pipe(ctx,PIPE_SEQ);
2588                         break;
2589                 case '&':
2590                         done_word(dest, ctx);
2591                         if (next=='&') {
2592                                 b_getch(input);
2593                                 done_pipe(ctx,PIPE_AND);
2594                         } else {
2595                                 done_pipe(ctx,PIPE_BG);
2596                         }
2597                         break;
2598                 case '|':
2599                         done_word(dest, ctx);
2600                         if (next=='|') {
2601                                 b_getch(input);
2602                                 done_pipe(ctx,PIPE_OR);
2603                         } else {
2604                                 /* we could pick up a file descriptor choice here
2605                                  * with redirect_opt_num(), but bash doesn't do it.
2606                                  * "echo foo 2| cat" yields "foo 2". */
2607                                 done_command(ctx);
2608                         }
2609                         break;
2610                 case '(':
2611                 case '{':
2612                         if (parse_group(dest, ctx, input, ch)!=0) return 1;
2613                         break;
2614                 case ')':
2615                 case '}':
2616                         syntax();   /* Proper use of this character caught by end_trigger */
2617                         return 1;
2618                         break;
2619                 default:
2620                         syntax();   /* this is really an internal logic error */
2621                         return 1;
2622                         }
2623                 }
2624         }
2625         /* complain if quote?  No, maybe we just finished a command substitution
2626          * that was quoted.  Example:
2627          * $ echo "`cat foo` plus more"
2628          * and we just got the EOF generated by the subshell that ran "cat foo"
2629          * The only real complaint is if we got an EOF when end_trigger != '\0',
2630          * that is, we were really supposed to get end_trigger, and never got
2631          * one before the EOF.  Can't use the standard "syntax error" return code,
2632          * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2633         debug_printf("leaving parse_stream (EOF)\n");
2634         if (end_trigger != '\0') return -1;
2635         return 0;
2636 }
2637
2638 void mapset(const unsigned char *set, int code)
2639 {
2640         const unsigned char *s;
2641         for (s=set; *s; s++) map[*s] = code;
2642 }
2643
2644 void update_ifs_map(void)
2645 {
2646         /* char *ifs and char map[256] are both globals. */
2647         ifs = getenv("IFS");
2648         if (ifs == NULL) ifs=" \t\n";
2649         /* Precompute a list of 'flow through' behavior so it can be treated
2650          * quickly up front.  Computation is necessary because of IFS.
2651          * Special case handling of IFS == " \t\n" is not implemented.
2652          * The map[] array only really needs two bits each, and on most machines
2653          * that would be faster because of the reduced L1 cache footprint.
2654          */
2655         memset(map,0,sizeof(map)); /* most characters flow through always */
2656         mapset("\\$'\"`", 3);      /* never flow through */
2657         mapset("<>;&|(){}#", 1);   /* flow through if quoted */
2658         mapset(ifs, 2);            /* also flow through if quoted */
2659 }
2660
2661 /* most recursion does not come through here, the exeception is
2662  * from builtin_source() */
2663 int parse_stream_outer(struct in_str *inp, int flag)
2664 {
2665
2666         struct p_context ctx;
2667         o_string temp=NULL_O_STRING;
2668         int rcode;
2669         do {
2670                 ctx.type = flag;
2671                 initialize_context(&ctx);
2672                 update_ifs_map();
2673                 if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING)) mapset(";$&|", 0);
2674                 inp->promptmode=1;
2675                 rcode = parse_stream(&temp, &ctx, inp, '\n');
2676                 if (rcode != 1 && ctx.old_flag != 0) {
2677                         syntax();
2678                 }
2679                 if (rcode != 1 && ctx.old_flag == 0) {
2680                         done_word(&temp, &ctx);
2681                         done_pipe(&ctx,PIPE_SEQ);
2682                         run_list(ctx.list_head);
2683                 } else {
2684                         if (ctx.old_flag != 0) {
2685                                 free(ctx.stack);
2686                                 b_reset(&temp);
2687                         }
2688                         temp.nonnull = 0;
2689                         temp.quote = 0;
2690                         inp->p = NULL;
2691                         free_pipe_list(ctx.list_head,0);
2692                 }
2693                 b_free(&temp);
2694         } while (rcode != -1 && !(flag & FLAG_EXIT_FROM_LOOP));   /* loop on syntax errors, return on EOF */
2695         return 0;
2696 }
2697
2698 static int parse_string_outer(const char *s, int flag)
2699 {
2700         struct in_str input;
2701         setup_string_in_str(&input, s);
2702         return parse_stream_outer(&input, flag);
2703 }
2704
2705 static int parse_file_outer(FILE *f)
2706 {
2707         int rcode;
2708         struct in_str input;
2709         setup_file_in_str(&input, f);
2710         rcode = parse_stream_outer(&input, FLAG_PARSE_SEMICOLON);
2711         return rcode;
2712 }
2713
2714 /* Make sure we have a controlling tty.  If we get started under a job
2715  * aware app (like bash for example), make sure we are now in charge so
2716  * we don't fight over who gets the foreground */
2717 static void setup_job_control(void)
2718 {
2719         static pid_t shell_pgrp;
2720         /* Loop until we are in the foreground.  */
2721         while (tcgetpgrp (shell_terminal) != (shell_pgrp = getpgrp ()))
2722                 kill (- shell_pgrp, SIGTTIN);
2723
2724         /* Ignore interactive and job-control signals.  */
2725         signal(SIGINT, SIG_IGN);
2726         signal(SIGQUIT, SIG_IGN);
2727         signal(SIGTERM, SIG_IGN);
2728         signal(SIGTSTP, SIG_IGN);
2729         signal(SIGTTIN, SIG_IGN);
2730         signal(SIGTTOU, SIG_IGN);
2731         signal(SIGCHLD, SIG_IGN);
2732
2733         /* Put ourselves in our own process group.  */
2734         setsid();
2735         shell_pgrp = getpid ();
2736         setpgid (shell_pgrp, shell_pgrp);
2737
2738         /* Grab control of the terminal.  */
2739         tcsetpgrp(shell_terminal, shell_pgrp);
2740 }
2741
2742 int hush_main(int argc, char **argv)
2743 {
2744         int opt;
2745         FILE *input;
2746         char **e = environ;
2747
2748         /* XXX what should these be while sourcing /etc/profile? */
2749         global_argc = argc;
2750         global_argv = argv;
2751
2752         /* (re?) initialize globals.  Sometimes hush_main() ends up calling
2753          * hush_main(), therefore we cannot rely on the BSS to zero out this
2754          * stuff.  Reset these to 0 every time. */
2755         ifs = NULL;
2756         /* map[] is taken care of with call to update_ifs_map() */
2757         fake_mode = 0;
2758         interactive = 0;
2759         close_me_head = NULL;
2760         last_bg_pid = 0;
2761         job_list = NULL;
2762         last_jobid = 0;
2763
2764         /* Initialize some more globals to non-zero values */
2765         set_cwd();
2766 #ifdef CONFIG_FEATURE_COMMAND_EDITING
2767         cmdedit_set_initial_prompt();
2768 #else
2769         PS1 = NULL;
2770 #endif
2771         PS2 = "> ";
2772
2773         /* initialize our shell local variables with the values
2774          * currently living in the environment */
2775         if (e) {
2776                 for (; *e; e++)
2777                         set_local_var(*e, 2);   /* without call putenv() */
2778         }
2779
2780         last_return_code=EXIT_SUCCESS;
2781
2782
2783         if (argv[0] && argv[0][0] == '-') {
2784                 debug_printf("\nsourcing /etc/profile\n");
2785                 if ((input = fopen("/etc/profile", "r")) != NULL) {
2786                         mark_open(fileno(input));
2787                         parse_file_outer(input);
2788                         mark_closed(fileno(input));
2789                         fclose(input);
2790                 }
2791         }
2792         input=stdin;
2793
2794         while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2795                 switch (opt) {
2796                         case 'c':
2797                                 {
2798                                         global_argv = argv+optind;
2799                                         global_argc = argc-optind;
2800                                         opt = parse_string_outer(optarg, FLAG_PARSE_SEMICOLON);
2801                                         goto final_return;
2802                                 }
2803                                 break;
2804                         case 'i':
2805                                 interactive++;
2806                                 break;
2807                         case 'f':
2808                                 fake_mode++;
2809                                 break;
2810                         default:
2811 #ifndef BB_VER
2812                                 fprintf(stderr, "Usage: sh [FILE]...\n"
2813                                                 "   or: sh -c command [args]...\n\n");
2814                                 exit(EXIT_FAILURE);
2815 #else
2816                                 bb_show_usage();
2817 #endif
2818                 }
2819         }
2820         /* A shell is interactive if the `-i' flag was given, or if all of
2821          * the following conditions are met:
2822          *        no -c command
2823          *    no arguments remaining or the -s flag given
2824          *    standard input is a terminal
2825          *    standard output is a terminal
2826          *    Refer to Posix.2, the description of the `sh' utility. */
2827         if (argv[optind]==NULL && input==stdin &&
2828                         isatty(fileno(stdin)) && isatty(fileno(stdout))) {
2829                 interactive++;
2830         }
2831
2832         debug_printf("\ninteractive=%d\n", interactive);
2833         if (interactive) {
2834                 /* Looks like they want an interactive shell */
2835 #ifndef CONFIG_FEATURE_SH_EXTRA_QUIET
2836                 printf( "\n\n" BB_BANNER " hush - the humble shell v0.01 (testing)\n");
2837                 printf( "Enter 'help' for a list of built-in commands.\n\n");
2838 #endif
2839                 setup_job_control();
2840         }
2841
2842         if (argv[optind]==NULL) {
2843                 opt=parse_file_outer(stdin);
2844                 goto final_return;
2845         }
2846
2847         debug_printf("\nrunning script '%s'\n", argv[optind]);
2848         global_argv = argv+optind;
2849         global_argc = argc-optind;
2850         input = bb_xfopen(argv[optind], "r");
2851         opt = parse_file_outer(input);
2852
2853 #ifdef CONFIG_FEATURE_CLEAN_UP
2854         fclose(input);
2855         if (cwd && cwd != bb_msg_unknown)
2856                 free((char*)cwd);
2857         {
2858                 struct variables *cur, *tmp;
2859                 for(cur = top_vars; cur; cur = tmp) {
2860                         tmp = cur->next;
2861                         if (!cur->flg_read_only) {
2862                                 free(cur->name);
2863                                 free(cur->value);
2864                                 free(cur);
2865                         }
2866                 }
2867         }
2868 #endif
2869
2870 final_return:
2871         return(opt?opt:last_return_code);
2872 }
2873
2874 static char *insert_var_value(char *inp)
2875 {
2876         int res_str_len = 0;
2877         int len;
2878         int done = 0;
2879         char *p, *p1, *res_str = NULL;
2880
2881         while ((p = strchr(inp, SPECIAL_VAR_SYMBOL))) {
2882                 if (p != inp) {
2883                         len = p - inp;
2884                         res_str = xrealloc(res_str, (res_str_len + len));
2885                         strncpy((res_str + res_str_len), inp, len);
2886                         res_str_len += len;
2887                 }
2888                 inp = ++p;
2889                 p = strchr(inp, SPECIAL_VAR_SYMBOL);
2890                 *p = '\0';
2891                 if ((p1 = lookup_param(inp))) {
2892                         len = res_str_len + strlen(p1);
2893                         res_str = xrealloc(res_str, (1 + len));
2894                         strcpy((res_str + res_str_len), p1);
2895                         res_str_len = len;
2896                 }
2897                 *p = SPECIAL_VAR_SYMBOL;
2898                 inp = ++p;
2899                 done = 1;
2900         }
2901         if (done) {
2902                 res_str = xrealloc(res_str, (1 + res_str_len + strlen(inp)));
2903                 strcpy((res_str + res_str_len), inp);
2904                 while ((p = strchr(res_str, '\n'))) {
2905                         *p = ' ';
2906                 }
2907         }
2908         return (res_str == NULL) ? inp : res_str;
2909 }
2910
2911 static char **make_list_in(char **inp, char *name)
2912 {
2913         int len, i;
2914         int name_len = strlen(name);
2915         int n = 0;
2916         char **list;
2917         char *p1, *p2, *p3;
2918
2919         /* create list of variable values */
2920         list = xmalloc(sizeof(*list));
2921         for (i = 0; inp[i]; i++) {
2922                 p3 = insert_var_value(inp[i]);
2923                 p1 = p3;
2924                 while (*p1) {
2925                         if ((*p1 == ' ')) {
2926                                 p1++;
2927                                 continue;
2928                         }
2929                         if ((p2 = strchr(p1, ' '))) {
2930                                 len = p2 - p1;
2931                         } else {
2932                                 len = strlen(p1);
2933                                 p2 = p1 + len;
2934                         }
2935                         /* we use n + 2 in realloc for list,because we add
2936                          * new element and then we will add NULL element */
2937                         list = xrealloc(list, sizeof(*list) * (n + 2));
2938                         list[n] = xmalloc(2 + name_len + len);
2939                         strcpy(list[n], name);
2940                         strcat(list[n], "=");
2941                         strncat(list[n], p1, len);
2942                         list[n++][name_len + len + 1] = '\0';
2943                         p1 = p2;
2944                 }
2945                 if (p3 != inp[i]) free(p3);
2946         }
2947         list[n] = NULL;
2948         return list;
2949 }
2950
2951 /* Make new string for parser */
2952 static char * make_string(char ** inp)
2953 {
2954         char *p;
2955         char *str = NULL;
2956         int n;
2957         int len = 2;
2958
2959         for (n = 0; inp[n]; n++) {
2960                 p = insert_var_value(inp[n]);
2961                 str = xrealloc(str, (len + strlen(p)));
2962                 if (n) {
2963                         strcat(str, " ");
2964                 } else {
2965                         *str = '\0';
2966                 }
2967                 strcat(str, p);
2968                 len = strlen(str) + 3;
2969                 if (p != inp[n]) free(p);
2970         }
2971         len = strlen(str);
2972         *(str + len) = '\n';
2973         *(str + len + 1) = '\0';
2974         return str;
2975 }