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