shell/hush.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * sh.c -- a prototype Bourne shell grammar parser
   4  *      Intended to follow the original Thompson and Ritchie
   5  *      "small and simple is beautiful" philosophy, which
   6  *      incidentally is a good match to today's BusyBox.
   7  *
   8  * Copyright (C) 2000,2001  Larry Doolittle  <larry@doolittle.boa.org>
   9  *
  10  * Credits:
  11  *      The parser routines proper are all original material, first
  12  *      written Dec 2000 and Jan 2001 by Larry Doolittle.  The
  13  *      execution engine, the builtins, and much of the underlying
  14  *      support has been adapted from busybox-0.49pre's lash, which is
  15  *      Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  16  *      written by Erik Andersen <andersen@codepoet.org>.  That, in turn,
  17  *      is based in part on ladsh.c, by Michael K. Johnson and Erik W.
  18  *      Troan, which they placed in the public domain.  I don't know
  19  *      how much of the Johnson/Troan code has survived the repeated
  20  *      rewrites.
  21  *
  22  * Other credits:
  23  *      simple_itoa() was lifted from boa-0.93.15
  24  *      b_addchr() derived from similar w_addchar function in glibc-2.2
  25  *      setup_redirect(), redirect_opt_num(), and big chunks of main()
  26  *        and many builtins derived from contributions by Erik Andersen
  27  *      miscellaneous bugfixes from Matt Kraai
  28  *
  29  * There are two big (and related) architecture differences between
  30  * this parser and the lash parser.  One is that this version is
  31  * actually designed from the ground up to understand nearly all
  32  * of the Bourne grammar.  The second, consequential change is that
  33  * the parser and input reader have been turned inside out.  Now,
  34  * the parser is in control, and asks for input as needed.  The old
  35  * way had the input reader in control, and it asked for parsing to
  36  * take place as needed.  The new way makes it much easier to properly
  37  * handle the recursion implicit in the various substitutions, especially
  38  * across continuation lines.
  39  *
  40  * Bash grammar not implemented: (how many of these were in original sh?)
  41  *      $@ (those sure look like weird quoting rules)
  42  *      $_
  43  *      ! negation operator for pipes
  44  *      &> and >& redirection of stdout+stderr
  45  *      Brace Expansion
  46  *      Tilde Expansion
  47  *      fancy forms of Parameter Expansion
  48  *      aliases
  49  *      Arithmetic Expansion
  50  *      <(list) and >(list) Process Substitution
  51  *      reserved words: case, esac, select, function
  52  *      Here Documents ( << word )
  53  *      Functions
  54  * Major bugs:
  55  *      job handling woefully incomplete and buggy
  56  *      reserved word execution woefully incomplete and buggy
  57  * to-do:
  58  *      port selected bugfixes from post-0.49 busybox lash - done?
  59  *      finish implementing reserved words: for, while, until, do, done
  60  *      change { and } from special chars to reserved words
  61  *      builtins: break, continue, eval, return, set, trap, ulimit
  62  *      test magic exec
  63  *      handle children going into background
  64  *      clean up recognition of null pipes
  65  *      check setting of global_argc and global_argv
  66  *      control-C handling, probably with longjmp
  67  *      follow IFS rules more precisely, including update semantics
  68  *      figure out what to do with backslash-newline
  69  *      explain why we use signal instead of sigaction
  70  *      propagate syntax errors, die on resource errors?
  71  *      continuation lines, both explicit and implicit - done?
  72  *      memory leak finding and plugging - done?
  73  *      more testing, especially quoting rules and redirection
  74  *      document how quoting rules not precisely followed for variable assignments
  75  *      maybe change map[] to use 2-bit entries
  76  *      (eventually) remove all the printf's
  77  *
  78  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  79  */
  80
  81 #include "busybox.h"
  82 #include <ctype.h>     /* isalpha, isdigit */
  83 #include <unistd.h>    /* getpid */
  84 #include <stdlib.h>    /* getenv, atoi */
  85 #include <string.h>    /* strchr */
  86 #include <stdio.h>     /* popen etc. */
  87 #include <glob.h>      /* glob, of course */
  88 #include <stdarg.h>    /* va_list */
  89 #include <errno.h>
  90 #include <fcntl.h>
  91 #include <getopt.h>    /* should be pretty obvious */
  92
  93 #include <sys/stat.h>  /* ulimit */
  94 #include <sys/types.h>
  95 #include <sys/wait.h>
  96 #include <signal.h>
  97
  98 /* #include <dmalloc.h> */
  99 /* #define DEBUG_SHELL */
 100
 101 #include "cmdedit.h"
 102
 103 #define SPECIAL_VAR_SYMBOL 03
 104 #define FLAG_EXIT_FROM_LOOP 1
 105 #define FLAG_PARSE_SEMICOLON (1 << 1)           /* symbol ';' is special for parser */
 106 #define FLAG_REPARSING           (1 << 2)               /* >=2nd pass */
 107
 108 typedef enum {
 109         REDIRECT_INPUT     = 1,
 110         REDIRECT_OVERWRITE = 2,
 111         REDIRECT_APPEND    = 3,
 112         REDIRECT_HEREIS    = 4,
 113         REDIRECT_IO        = 5
 114 } redir_type;
 115
 116 /* The descrip member of this structure is only used to make debugging
 117  * output pretty */
 118 static const struct {int mode; int default_fd; const char *descrip;} redir_table[] = {
 119         { 0,                         0, "()" },
 120         { O_RDONLY,                  0, "<"  },
 121         { O_CREAT|O_TRUNC|O_WRONLY,  1, ">"  },
 122         { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" },
 123         { O_RDONLY,                 -1, "<<" },
 124         { O_RDWR,                    1, "<>" }
 125 };
 126
 127 typedef enum {
 128         PIPE_SEQ = 1,
 129         PIPE_AND = 2,
 130         PIPE_OR  = 3,
 131         PIPE_BG  = 4,
 132 } pipe_style;
 133
 134 /* might eventually control execution */
 135 typedef enum {
 136         RES_NONE  = 0,
 137         RES_IF    = 1,
 138         RES_THEN  = 2,
 139         RES_ELIF  = 3,
 140         RES_ELSE  = 4,
 141         RES_FI    = 5,
 142         RES_FOR   = 6,
 143         RES_WHILE = 7,
 144         RES_UNTIL = 8,
 145         RES_DO    = 9,
 146         RES_DONE  = 10,
 147         RES_XXXX  = 11,
 148         RES_IN    = 12,
 149         RES_SNTX  = 13
 150 } reserved_style;
 151 #define FLAG_END   (1<<RES_NONE)
 152 #define FLAG_IF    (1<<RES_IF)
 153 #define FLAG_THEN  (1<<RES_THEN)
 154 #define FLAG_ELIF  (1<<RES_ELIF)
 155 #define FLAG_ELSE  (1<<RES_ELSE)
 156 #define FLAG_FI    (1<<RES_FI)
 157 #define FLAG_FOR   (1<<RES_FOR)
 158 #define FLAG_WHILE (1<<RES_WHILE)
 159 #define FLAG_UNTIL (1<<RES_UNTIL)
 160 #define FLAG_DO    (1<<RES_DO)
 161 #define FLAG_DONE  (1<<RES_DONE)
 162 #define FLAG_IN    (1<<RES_IN)
 163 #define FLAG_START (1<<RES_XXXX)
 164
 165 /* This holds pointers to the various results of parsing */
 166 struct p_context {
 167         struct child_prog *child;
 168         struct pipe *list_head;
 169         struct pipe *pipe;
 170         struct redir_struct *pending_redirect;
 171         reserved_style w;
 172         int old_flag;                           /* for figuring out valid reserved words */
 173         struct p_context *stack;
 174         int type;                       /* define type of parser : ";$" common or special symbol */
 175         /* How about quoting status? */
 176 };
 177
 178 struct redir_struct {
 179         redir_type type;                        /* type of redirection */
 180         int fd;                                         /* file descriptor being redirected */
 181         int dup;                                        /* -1, or file descriptor being duplicated */
 182         struct redir_struct *next;      /* pointer to the next redirect in the list */
 183         glob_t word;                            /* *word.gl_pathv is the filename */
 184 };
 185
 186 struct child_prog {
 187         pid_t pid;                                      /* 0 if exited */
 188         char **argv;                            /* program name and arguments */
 189         struct pipe *group;                     /* if non-NULL, first in group or subshell */
 190         int subshell;                           /* flag, non-zero if group must be forked */
 191         struct redir_struct *redirects; /* I/O redirections */
 192         glob_t glob_result;                     /* result of parameter globbing */
 193         int is_stopped;                         /* is the program currently running? */
 194         struct pipe *family;            /* pointer back to the child's parent pipe */
 195         int sp;                         /* number of SPECIAL_VAR_SYMBOL */
 196         int type;
 197 };
 198
 199 struct pipe {
 200         int jobid;                                      /* job number */
 201         int num_progs;                          /* total number of programs in job */
 202         int running_progs;                      /* number of programs running */
 203         char *text;                                     /* name of job */
 204         char *cmdbuf;                           /* buffer various argv's point into */
 205         pid_t pgrp;                                     /* process group ID for the job */
 206         struct child_prog *progs;       /* array of commands in pipe */
 207         struct pipe *next;                      /* to track background commands */
 208         int stopped_progs;                      /* number of programs alive, but stopped */
 209         int job_context;                        /* bitmask defining current context */
 210         pipe_style followup;            /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */
 211         reserved_style r_mode;          /* supports if, for, while, until */
 212 };
 213
 214 struct close_me {
 215         int fd;
 216         struct close_me *next;
 217 };
 218
 219 struct variables {
 220         char *name;
 221         char *value;
 222         int flg_export;
 223         int flg_read_only;
 224         struct variables *next;
 225 };
 226
 227 /* globals, connect us to the outside world
 228  * the first three support $?, $#, and $1 */
 229 static char **global_argv;
 230 static int global_argc;
 231 static int last_return_code;
 232 extern char **environ; /* This is in <unistd.h>, but protected with __USE_GNU */
 233
 234 /* "globals" within this file */
 235 static char *ifs;
 236 static unsigned char map[256];
 237 static int fake_mode;
 238 static int interactive;
 239 static struct close_me *close_me_head;
 240 static const char *cwd;
 241 static struct pipe *job_list;
 242 static unsigned int last_bg_pid;
 243 static int last_jobid;
 244 static unsigned int shell_terminal;
 245 static char *PS1;
 246 static char *PS2;
 247 static struct variables shell_ver = { "HUSH_VERSION", "0.01", 1, 1, 0 };
 248 static struct variables *top_vars = &shell_ver;
 249
 250
 251 #define B_CHUNK (100)
 252 #define B_NOSPAC 1
 253
 254 typedef struct {
 255         char *data;
 256         int length;
 257         int maxlen;
 258         int quote;
 259         int nonnull;
 260 } o_string;
 261 #define NULL_O_STRING {NULL,0,0,0,0}
 262 /* used for initialization:
 263         o_string foo = NULL_O_STRING; */
 264
 265 /* I can almost use ordinary FILE *.  Is open_memstream() universally
 266  * available?  Where is it documented? */
 267 struct in_str {
 268         const char *p;
 269         char peek_buf[2];
 270         int __promptme;
 271         int promptmode;
 272         FILE *file;
 273         int (*get) (struct in_str *);
 274         int (*peek) (struct in_str *);
 275 };
 276 #define b_getch(input) ((input)->get(input))
 277 #define b_peek(input) ((input)->peek(input))
 278
 279 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
 280
 281 struct built_in_command {
 282         const char *cmd;                        /* name */
 283         const char *descr;                      /* description */
 284         int (*function) (struct child_prog *);  /* function ptr */
 285 };
 286
 287 /* belongs in busybox.h */
 288 static int max(int a, int b) {
 289         return (a>b)?a:b;
 290 }
 291
 292 /* This should be in utility.c */
 293 #ifdef DEBUG_SHELL
 294 static void debug_printf(const char *format, ...)
 295 {
 296         va_list args;
 297         va_start(args, format);
 298         vfprintf(stderr, format, args);
 299         va_end(args);
 300 }
 301 /* broken, of course, but OK for testing */
 302 static char *indenter(int i)
 303 {
 304         static char blanks[]="                                    ";
 305         return &blanks[sizeof(blanks)-i-1];
 306 }
 307 #else
 308 #define debug_printf(...) do {;} while(0);
 309 #endif
 310 #define final_printf debug_printf
 311
 312 static void __syntax(char *file, int line) {
 313         bb_error_msg("syntax error %s:%d", file, line);
 314 }
 315 // NB: was __FILE__, but that produces full path sometimess, so...
 316 #define syntax() __syntax("hush.c", __LINE__)
 317
 318 /* Index of subroutines: */
 319 /*   function prototypes for builtins */
 320 static int builtin_cd(struct child_prog *child);
 321 static int builtin_env(struct child_prog *child);
 322 static int builtin_eval(struct child_prog *child);
 323 static int builtin_exec(struct child_prog *child);
 324 static int builtin_exit(struct child_prog *child);
 325 static int builtin_export(struct child_prog *child);
 326 static int builtin_fg_bg(struct child_prog *child);
 327 static int builtin_help(struct child_prog *child);
 328 static int builtin_jobs(struct child_prog *child);
 329 static int builtin_pwd(struct child_prog *child);
 330 static int builtin_read(struct child_prog *child);
 331 static int builtin_set(struct child_prog *child);
 332 static int builtin_shift(struct child_prog *child);
 333 static int builtin_source(struct child_prog *child);
 334 static int builtin_umask(struct child_prog *child);
 335 static int builtin_unset(struct child_prog *child);
 336 static int builtin_not_written(struct child_prog *child);
 337 /*   o_string manipulation: */
 338 static int b_check_space(o_string *o, int len);
 339 static int b_addchr(o_string *o, int ch);
 340 static void b_reset(o_string *o);
 341 static int b_addqchr(o_string *o, int ch, int quote);
 342 static int b_adduint(o_string *o, unsigned int i);
 343 /*  in_str manipulations: */
 344 static int static_get(struct in_str *i);
 345 static int static_peek(struct in_str *i);
 346 static int file_get(struct in_str *i);
 347 static int file_peek(struct in_str *i);
 348 static void setup_file_in_str(struct in_str *i, FILE *f);
 349 static void setup_string_in_str(struct in_str *i, const char *s);
 350 /*  close_me manipulations: */
 351 static void mark_open(int fd);
 352 static void mark_closed(int fd);
 353 static void close_all(void);
 354 /*  "run" the final data structures: */
 355 static int free_pipe_list(struct pipe *head, int indent);
 356 static int free_pipe(struct pipe *pi, int indent);
 357 /*  really run the final data structures: */
 358 static int setup_redirects(struct child_prog *prog, int squirrel[]);
 359 static int run_list_real(struct pipe *pi);
 360 static void pseudo_exec(struct child_prog *child) ATTRIBUTE_NORETURN;
 361 static int run_pipe_real(struct pipe *pi);
 362 /*   extended glob support: */
 363 static int globhack(const char *src, int flags, glob_t *pglob);
 364 static int glob_needed(const char *s);
 365 static int xglob(o_string *dest, int flags, glob_t *pglob);
 366 /*   variable assignment: */
 367 static int is_assignment(const char *s);
 368 /*   data structure manipulation: */
 369 static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input);
 370 static void initialize_context(struct p_context *ctx);
 371 static int done_word(o_string *dest, struct p_context *ctx);
 372 static int done_command(struct p_context *ctx);
 373 static int done_pipe(struct p_context *ctx, pipe_style type);
 374 /*   primary string parsing: */
 375 static int redirect_dup_num(struct in_str *input);
 376 static int redirect_opt_num(o_string *o);
 377 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end);
 378 static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch);
 379 static char *lookup_param(char *src);
 380 static char *make_string(char **inp);
 381 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input);
 382 static int parse_string(o_string *dest, struct p_context *ctx, const char *src);
 383 static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, int end_trigger);
 384 /*   setup: */
 385 static int parse_stream_outer(struct in_str *inp, int flag);
 386 static int parse_string_outer(const char *s, int flag);
 387 static int parse_file_outer(FILE *f);
 388 /*   job management: */
 389 static int checkjobs(struct pipe* fg_pipe);
 390 static void insert_bg_job(struct pipe *pi);
 391 static void remove_bg_job(struct pipe *pi);
 392 /*     local variable support */
 393 static char **make_list_in(char **inp, char *name);
 394 static char *insert_var_value(char *inp);
 395 static char *get_local_var(const char *var);
 396 static void  unset_local_var(const char *name);
 397 static int set_local_var(const char *s, int flg_export);
 398
 399 /* Table of built-in functions.  They can be forked or not, depending on
 400  * context: within pipes, they fork.  As simple commands, they do not.
 401  * When used in non-forking context, they can change global variables
 402  * in the parent shell process.  If forked, of course they cannot.
 403  * For example, 'unset foo | whatever' will parse and run, but foo will
 404  * still be set at the end. */
 405 static const struct built_in_command bltins[] = {
 406         {"bg", "Resume a job in the background", builtin_fg_bg},
 407         {"break", "Exit for, while or until loop", builtin_not_written},
 408         {"cd", "Change working directory", builtin_cd},
 409         {"continue", "Continue for, while or until loop", builtin_not_written},
 410         {"env", "Print all environment variables", builtin_env},
 411         {"eval", "Construct and run shell command", builtin_eval},
 412         {"exec", "Exec command, replacing this shell with the exec'd process",
 413                 builtin_exec},
 414         {"exit", "Exit from shell()", builtin_exit},
 415         {"export", "Set environment variable", builtin_export},
 416         {"fg", "Bring job into the foreground", builtin_fg_bg},
 417         {"jobs", "Lists the active jobs", builtin_jobs},
 418         {"pwd", "Print current directory", builtin_pwd},
 419         {"read", "Input environment variable", builtin_read},
 420         {"return", "Return from a function", builtin_not_written},
 421         {"set", "Set/unset shell local variables", builtin_set},
 422         {"shift", "Shift positional parameters", builtin_shift},
 423         {"trap", "Trap signals", builtin_not_written},
 424         {"ulimit","Controls resource limits", builtin_not_written},
 425         {"umask","Sets file creation mask", builtin_umask},
 426         {"unset", "Unset environment variable", builtin_unset},
 427         {".", "Source-in and run commands in a file", builtin_source},
 428         {"help", "List shell built-in commands", builtin_help},
 429         {NULL, NULL, NULL}
 430 };
 431
 432 static const char *set_cwd(void)
 433 {
 434         if(cwd==bb_msg_unknown)
 435                 cwd = NULL;     /* xgetcwd(arg) called free(arg) */
 436         cwd = xgetcwd((char *)cwd);
 437         if (!cwd)
 438                 cwd = bb_msg_unknown;
 439         return cwd;
 440 }
 441
 442 /* built-in 'eval' handler */
 443 static int builtin_eval(struct child_prog *child)
 444 {
 445         char *str = NULL;
 446         int rcode = EXIT_SUCCESS;
 447
 448         if (child->argv[1]) {
 449                 str = make_string(child->argv + 1);
 450                 parse_string_outer(str, FLAG_EXIT_FROM_LOOP |
 451                                         FLAG_PARSE_SEMICOLON);
 452                 free(str);
 453                 rcode = last_return_code;
 454         }
 455         return rcode;
 456 }
 457
 458 /* built-in 'cd <path>' handler */
 459 static int builtin_cd(struct child_prog *child)
 460 {
 461         char *newdir;
 462         if (child->argv[1] == NULL)
 463                 newdir = getenv("HOME");
 464         else
 465                 newdir = child->argv[1];
 466         if (chdir(newdir)) {
 467                 printf("cd: %s: %s\n", newdir, strerror(errno));
 468                 return EXIT_FAILURE;
 469         }
 470         set_cwd();
 471         return EXIT_SUCCESS;
 472 }
 473
 474 /* built-in 'env' handler */
 475 static int builtin_env(struct child_prog *dummy ATTRIBUTE_UNUSED)
 476 {
 477         char **e = environ;
 478         if (e == NULL) return EXIT_FAILURE;
 479         for (; *e; e++) {
 480                 puts(*e);
 481         }
 482         return EXIT_SUCCESS;
 483 }
 484
 485 /* built-in 'exec' handler */
 486 static int builtin_exec(struct child_prog *child)
 487 {
 488         if (child->argv[1] == NULL)
 489                 return EXIT_SUCCESS;   /* Really? */
 490         child->argv++;
 491         pseudo_exec(child);
 492         /* never returns */
 493 }
 494
 495 /* built-in 'exit' handler */
 496 static int builtin_exit(struct child_prog *child)
 497 {
 498         if (child->argv[1] == NULL)
 499                 exit(last_return_code);
 500         exit (atoi(child->argv[1]));
 501 }
 502
 503 /* built-in 'export VAR=value' handler */
 504 static int builtin_export(struct child_prog *child)
 505 {
 506         int res = 0;
 507         char *name = child->argv[1];
 508
 509         if (name == NULL) {
 510                 return builtin_env(child);
 511         }
 512
 513         name = strdup(name);
 514
 515         if(name) {
 516                 char *value = strchr(name, '=');
 517
 518                 if (!value) {
 519                         char *tmp;
 520                         /* They are exporting something without an =VALUE */
 521
 522                         value = get_local_var(name);
 523                         if (value) {
 524                                 size_t ln = strlen(name);
 525
 526                                 tmp = realloc(name, ln+strlen(value)+2);
 527                                 if(tmp==NULL)
 528                                         res = -1;
 529                                 else {
 530                                         sprintf(tmp+ln, "=%s", value);
 531                                         name = tmp;
 532                                 }
 533                         } else {
 534                                 /* bash does not return an error when trying to export
 535                                  * an undefined variable.  Do likewise. */
 536                                 res = 1;
 537                         }
 538                 }
 539         }
 540         if (res<0)
 541                 bb_perror_msg("export");
 542         else if(res==0)
 543                 res = set_local_var(name, 1);
 544         else
 545                 res = 0;
 546         free(name);
 547         return res;
 548 }
 549
 550 /* built-in 'fg' and 'bg' handler */
 551 static int builtin_fg_bg(struct child_prog *child)
 552 {
 553         int i, jobnum;
 554         struct pipe *pi=NULL;
 555
 556         if (!interactive)
 557                 return EXIT_FAILURE;
 558         /* If they gave us no args, assume they want the last backgrounded task */
 559         if (!child->argv[1]) {
 560                 for (pi = job_list; pi; pi = pi->next) {
 561                         if (pi->jobid == last_jobid) {
 562                                 break;
 563                         }
 564                 }
 565                 if (!pi) {
 566                         bb_error_msg("%s: no current job", child->argv[0]);
 567                         return EXIT_FAILURE;
 568                 }
 569         } else {
 570                 if (sscanf(child->argv[1], "%%%d", &jobnum) != 1) {
 571                         bb_error_msg("%s: bad argument '%s'", child->argv[0], child->argv[1]);
 572                         return EXIT_FAILURE;
 573                 }
 574                 for (pi = job_list; pi; pi = pi->next) {
 575                         if (pi->jobid == jobnum) {
 576                                 break;
 577                         }
 578                 }
 579                 if (!pi) {
 580                         bb_error_msg("%s: %d: no such job", child->argv[0], jobnum);
 581                         return EXIT_FAILURE;
 582                 }
 583         }
 584
 585         if (*child->argv[0] == 'f') {
 586                 /* Put the job into the foreground.  */
 587                 tcsetpgrp(shell_terminal, pi->pgrp);
 588         }
 589
 590         /* Restart the processes in the job */
 591         for (i = 0; i < pi->num_progs; i++)
 592                 pi->progs[i].is_stopped = 0;
 593
 594         if ( (i=kill(- pi->pgrp, SIGCONT)) < 0) {
 595                 if (i == ESRCH) {
 596                         remove_bg_job(pi);
 597                 } else {
 598                         bb_perror_msg("kill (SIGCONT)");
 599                 }
 600         }
 601
 602         pi->stopped_progs = 0;
 603         return EXIT_SUCCESS;
 604 }
 605
 606 /* built-in 'help' handler */
 607 static int builtin_help(struct child_prog *dummy ATTRIBUTE_UNUSED)
 608 {
 609         const struct built_in_command *x;
 610
 611         printf("\nBuilt-in commands:\n");
 612         printf("-------------------\n");
 613         for (x = bltins; x->cmd; x++) {
 614                 if (x->descr==NULL)
 615                         continue;
 616                 printf("%s\t%s\n", x->cmd, x->descr);
 617         }
 618         printf("\n\n");
 619         return EXIT_SUCCESS;
 620 }
 621
 622 /* built-in 'jobs' handler */
 623 static int builtin_jobs(struct child_prog *child ATTRIBUTE_UNUSED)
 624 {
 625         struct pipe *job;
 626         char *status_string;
 627
 628         for (job = job_list; job; job = job->next) {
 629                 if (job->running_progs == job->stopped_progs)
 630                         status_string = "Stopped";
 631                 else
 632                         status_string = "Running";
 633
 634                 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
 635         }
 636         return EXIT_SUCCESS;
 637 }
 638
 639
 640 /* built-in 'pwd' handler */
 641 static int builtin_pwd(struct child_prog *dummy ATTRIBUTE_UNUSED)
 642 {
 643         puts(set_cwd());
 644         return EXIT_SUCCESS;
 645 }
 646
 647 /* built-in 'read VAR' handler */
 648 static int builtin_read(struct child_prog *child)
 649 {
 650         int res;
 651
 652         if (child->argv[1]) {
 653                 char string[BUFSIZ];
 654                 char *var = 0;
 655
 656                 string[0] = 0;  /* In case stdin has only EOF */
 657                 /* read string */
 658                 fgets(string, sizeof(string), stdin);
 659                 chomp(string);
 660                 var = malloc(strlen(child->argv[1])+strlen(string)+2);
 661                 if(var) {
 662                         sprintf(var, "%s=%s", child->argv[1], string);
 663                         res = set_local_var(var, 0);
 664                 } else
 665                         res = -1;
 666                 if (res)
 667                         bb_perror_msg("read");
 668                 free(var);      /* So not move up to avoid breaking errno */
 669                 return res;
 670         } else {
 671                 do res=getchar(); while(res!='\n' && res!=EOF);
 672                 return 0;
 673         }
 674 }
 675
 676 /* built-in 'set VAR=value' handler */
 677 static int builtin_set(struct child_prog *child)
 678 {
 679         char *temp = child->argv[1];
 680         struct variables *e;
 681
 682         if (temp == NULL)
 683                 for(e = top_vars; e; e=e->next)
 684                         printf("%s=%s\n", e->name, e->value);
 685         else
 686                 set_local_var(temp, 0);
 687
 688                 return EXIT_SUCCESS;
 689 }
 690
 691
 692 /* Built-in 'shift' handler */
 693 static int builtin_shift(struct child_prog *child)
 694 {
 695         int n=1;
 696         if (child->argv[1]) {
 697                 n=atoi(child->argv[1]);
 698         }
 699         if (n>=0 && n<global_argc) {
 700                 /* XXX This probably breaks $0 */
 701                 global_argc -= n;
 702                 global_argv += n;
 703                 return EXIT_SUCCESS;
 704         } else {
 705                 return EXIT_FAILURE;
 706         }
 707 }
 708
 709 /* Built-in '.' handler (read-in and execute commands from file) */
 710 static int builtin_source(struct child_prog *child)
 711 {
 712         FILE *input;
 713         int status;
 714
 715         if (child->argv[1] == NULL)
 716                 return EXIT_FAILURE;
 717
 718         /* XXX search through $PATH is missing */
 719         input = fopen(child->argv[1], "r");
 720         if (!input) {
 721                 bb_error_msg("cannot open '%s'", child->argv[1]);
 722                 return EXIT_FAILURE;
 723         }
 724
 725         /* Now run the file */
 726         /* XXX argv and argc are broken; need to save old global_argv
 727          * (pointer only is OK!) on this stack frame,
 728          * set global_argv=child->argv+1, recurse, and restore. */
 729         mark_open(fileno(input));
 730         status = parse_file_outer(input);
 731         mark_closed(fileno(input));
 732         fclose(input);
 733         return status;
 734 }
 735
 736 static int builtin_umask(struct child_prog *child)
 737 {
 738         mode_t new_umask;
 739         const char *arg = child->argv[1];
 740         char *end;
 741         if (arg) {
 742                 new_umask=strtoul(arg, &end, 8);
 743                 if (*end!='\0' || end == arg) {
 744                         return EXIT_FAILURE;
 745                 }
 746         } else {
 747                 printf("%.3o\n", (unsigned int) (new_umask=umask(0)));
 748         }
 749         umask(new_umask);
 750         return EXIT_SUCCESS;
 751 }
 752
 753 /* built-in 'unset VAR' handler */
 754 static int builtin_unset(struct child_prog *child)
 755 {
 756         /* bash returned already true */
 757         unset_local_var(child->argv[1]);
 758         return EXIT_SUCCESS;
 759 }
 760
 761 static int builtin_not_written(struct child_prog *child)
 762 {
 763         printf("builtin_%s not written\n",child->argv[0]);
 764         return EXIT_FAILURE;
 765 }
 766
 767 static int b_check_space(o_string *o, int len)
 768 {
 769         /* It would be easy to drop a more restrictive policy
 770          * in here, such as setting a maximum string length */
 771         if (o->length + len > o->maxlen) {
 772                 char *old_data = o->data;
 773                 /* assert (data == NULL || o->maxlen != 0); */
 774                 o->maxlen += max(2*len, B_CHUNK);
 775                 o->data = realloc(o->data, 1 + o->maxlen);
 776                 if (o->data == NULL) {
 777                         free(old_data);
 778                 }
 779         }
 780         return o->data == NULL;
 781 }
 782
 783 static int b_addchr(o_string *o, int ch)
 784 {
 785         debug_printf("b_addchr: %c %d %p\n", ch, o->length, o);
 786         if (b_check_space(o, 1)) return B_NOSPAC;
 787         o->data[o->length] = ch;
 788         o->length++;
 789         o->data[o->length] = '\0';
 790         return 0;
 791 }
 792
 793 static void b_reset(o_string *o)
 794 {
 795         o->length = 0;
 796         o->nonnull = 0;
 797         if (o->data != NULL) *o->data = '\0';
 798 }
 799
 800 static void b_free(o_string *o)
 801 {
 802         b_reset(o);
 803         free(o->data);
 804         o->data = NULL;
 805         o->maxlen = 0;
 806 }
 807
 808 /* My analysis of quoting semantics tells me that state information
 809  * is associated with a destination, not a source.
 810  */
 811 static int b_addqchr(o_string *o, int ch, int quote)
 812 {
 813         if (quote && strchr("*?[\\",ch)) {
 814                 int rc;
 815                 rc = b_addchr(o, '\\');
 816                 if (rc) return rc;
 817         }
 818         return b_addchr(o, ch);
 819 }
 820
 821 /* belongs in utility.c */
 822 static char *simple_itoa(unsigned int i)
 823 {
 824         /* 21 digits plus null terminator, good for 64-bit or smaller ints */
 825         static char local[22];
 826         char *p = &local[21];
 827         *p-- = '\0';
 828         do {
 829                 *p-- = '0' + i % 10;
 830                 i /= 10;
 831         } while (i > 0);
 832         return p + 1;
 833 }
 834
 835 static int b_adduint(o_string *o, unsigned int i)
 836 {
 837         int r;
 838         char *p = simple_itoa(i);
 839         /* no escape checking necessary */
 840         do r=b_addchr(o, *p++); while (r==0 && *p);
 841         return r;
 842 }
 843
 844 static int static_get(struct in_str *i)
 845 {
 846         int ch=*i->p++;
 847         if (ch=='\0') return EOF;
 848         return ch;
 849 }
 850
 851 static int static_peek(struct in_str *i)
 852 {
 853         return *i->p;
 854 }
 855
 856 static void cmdedit_set_initial_prompt(void)
 857 {
 858 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
 859         PS1 = NULL;
 860 #else
 861         PS1 = getenv("PS1");
 862         if(PS1==0)
 863                 PS1 = "\\w \\$ ";
 864 #endif
 865 }
 866
 867 static void setup_prompt_string(int promptmode, char **prompt_str)
 868 {
 869         debug_printf("setup_prompt_string %d ",promptmode);
 870 #ifndef CONFIG_FEATURE_SH_FANCY_PROMPT
 871         /* Set up the prompt */
 872         if (promptmode == 1) {
 873                 free(PS1);
 874                 PS1=xmalloc(strlen(cwd)+4);
 875                 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
 876                 *prompt_str = PS1;
 877         } else {
 878                 *prompt_str = PS2;
 879         }
 880 #else
 881         *prompt_str = (promptmode==1)? PS1 : PS2;
 882 #endif
 883         debug_printf("result %s\n",*prompt_str);
 884 }
 885
 886 static void get_user_input(struct in_str *i)
 887 {
 888         char *prompt_str;
 889         static char the_command[BUFSIZ];
 890
 891         setup_prompt_string(i->promptmode, &prompt_str);
 892 #ifdef CONFIG_FEATURE_COMMAND_EDITING
 893         /*
 894          ** enable command line editing only while a command line
 895          ** is actually being read; otherwise, we'll end up bequeathing
 896          ** atexit() handlers and other unwanted stuff to our
 897          ** child processes (rob@sysgo.de)
 898          */
 899         cmdedit_read_input(prompt_str, the_command);
 900 #else
 901         fputs(prompt_str, stdout);
 902         fflush(stdout);
 903         the_command[0]=fgetc(i->file);
 904         the_command[1]='\0';
 905 #endif
 906         fflush(stdout);
 907         i->p = the_command;
 908 }
 909
 910 /* This is the magic location that prints prompts
 911  * and gets data back from the user */
 912 static int file_get(struct in_str *i)
 913 {
 914         int ch;
 915
 916         ch = 0;
 917         /* If there is data waiting, eat it up */
 918         if (i->p && *i->p) {
 919                 ch=*i->p++;
 920         } else {
 921                 /* need to double check i->file because we might be doing something
 922                  * more complicated by now, like sourcing or substituting. */
 923                 if (i->__promptme && interactive && i->file == stdin) {
 924                         while(! i->p || (interactive && strlen(i->p)==0) ) {
 925                                 get_user_input(i);
 926                         }
 927                         i->promptmode=2;
 928                         i->__promptme = 0;
 929                         if (i->p && *i->p) {
 930                                 ch=*i->p++;
 931                         }
 932                 } else {
 933                         ch = fgetc(i->file);
 934                 }
 935
 936                 debug_printf("b_getch: got a %d\n", ch);
 937         }
 938         if (ch == '\n') i->__promptme=1;
 939         return ch;
 940 }
 941
 942 /* All the callers guarantee this routine will never be
 943  * used right after a newline, so prompting is not needed.
 944  */
 945 static int file_peek(struct in_str *i)
 946 {
 947         if (i->p && *i->p) {
 948                 return *i->p;
 949         } else {
 950                 i->peek_buf[0] = fgetc(i->file);
 951                 i->peek_buf[1] = '\0';
 952                 i->p = i->peek_buf;
 953                 debug_printf("b_peek: got a %d\n", *i->p);
 954                 return *i->p;
 955         }
 956 }
 957
 958 static void setup_file_in_str(struct in_str *i, FILE *f)
 959 {
 960         i->peek = file_peek;
 961         i->get = file_get;
 962         i->__promptme=1;
 963         i->promptmode=1;
 964         i->file = f;
 965         i->p = NULL;
 966 }
 967
 968 static void setup_string_in_str(struct in_str *i, const char *s)
 969 {
 970         i->peek = static_peek;
 971         i->get = static_get;
 972         i->__promptme=1;
 973         i->promptmode=1;
 974         i->p = s;
 975 }
 976
 977 static void mark_open(int fd)
 978 {
 979         struct close_me *new = xmalloc(sizeof(struct close_me));
 980         new->fd = fd;
 981         new->next = close_me_head;
 982         close_me_head = new;
 983 }
 984
 985 static void mark_closed(int fd)
 986 {
 987         struct close_me *tmp;
 988         if (close_me_head == NULL || close_me_head->fd != fd)
 989                 bb_error_msg_and_die("corrupt close_me");
 990         tmp = close_me_head;
 991         close_me_head = close_me_head->next;
 992         free(tmp);
 993 }
 994
 995 static void close_all(void)
 996 {
 997         struct close_me *c;
 998         for (c=close_me_head; c; c=c->next) {
 999                 close(c->fd);
1000         }
1001         close_me_head = NULL;
1002 }
1003
1004 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
1005  * and stderr if they are redirected. */
1006 static int setup_redirects(struct child_prog *prog, int squirrel[])
1007 {
1008         int openfd, mode;
1009         struct redir_struct *redir;
1010
1011         for (redir=prog->redirects; redir; redir=redir->next) {
1012                 if (redir->dup == -1 && redir->word.gl_pathv == NULL) {
1013                         /* something went wrong in the parse.  Pretend it didn't happen */
1014                         continue;
1015                 }
1016                 if (redir->dup == -1) {
1017                         mode=redir_table[redir->type].mode;
1018                         openfd = open(redir->word.gl_pathv[0], mode, 0666);
1019                         if (openfd < 0) {
1020                         /* this could get lost if stderr has been redirected, but
1021                            bash and ash both lose it as well (though zsh doesn't!) */
1022                                 bb_perror_msg("error opening %s", redir->word.gl_pathv[0]);
1023                                 return 1;
1024                         }
1025                 } else {
1026                         openfd = redir->dup;
1027                 }
1028
1029                 if (openfd != redir->fd) {
1030                         if (squirrel && redir->fd < 3) {
1031                                 squirrel[redir->fd] = dup(redir->fd);
1032                         }
1033                         if (openfd == -3) {
1034                                 close(openfd);
1035                         } else {
1036                                 dup2(openfd, redir->fd);
1037                                 if (redir->dup == -1)
1038                                         close (openfd);
1039                         }
1040                 }
1041         }
1042         return 0;
1043 }
1044
1045 static void restore_redirects(int squirrel[])
1046 {
1047         int i, fd;
1048         for (i=0; i<3; i++) {
1049                 fd = squirrel[i];
1050                 if (fd != -1) {
1051                         /* No error checking.  I sure wouldn't know what
1052                          * to do with an error if I found one! */
1053                         dup2(fd, i);
1054                         close(fd);
1055                 }
1056         }
1057 }
1058
1059 /* never returns */
1060 /* XXX no exit() here.  If you don't exec, use _exit instead.
1061  * The at_exit handlers apparently confuse the calling process,
1062  * in particular stdin handling.  Not sure why? */
1063 static void pseudo_exec(struct child_prog *child)
1064 {
1065         int i, rcode;
1066         char *p;
1067         const struct built_in_command *x;
1068         if (child->argv) {
1069                 for (i=0; is_assignment(child->argv[i]); i++) {
1070                         debug_printf("pid %d environment modification: %s\n",getpid(),child->argv[i]);
1071                         p = insert_var_value(child->argv[i]);
1072                         putenv(strdup(p));
1073                         if (p != child->argv[i]) free(p);
1074                 }
1075                 child->argv+=i;  /* XXX this hack isn't so horrible, since we are about
1076                                         to exit, and therefore don't need to keep data
1077                                         structures consistent for free() use. */
1078                 /* If a variable is assigned in a forest, and nobody listens,
1079                  * was it ever really set?
1080                  */
1081                 if (child->argv[0] == NULL) {
1082                         _exit(EXIT_SUCCESS);
1083                 }
1084
1085                 /*
1086                  * Check if the command matches any of the builtins.
1087                  * Depending on context, this might be redundant.  But it's
1088                  * easier to waste a few CPU cycles than it is to figure out
1089                  * if this is one of those cases.
1090                  */
1091                 for (x = bltins; x->cmd; x++) {
1092                         if (strcmp(child->argv[0], x->cmd) == 0 ) {
1093                                 debug_printf("builtin exec %s\n", child->argv[0]);
1094                                 rcode = x->function(child);
1095                                 fflush(stdout);
1096                                 _exit(rcode);
1097                         }
1098                 }
1099
1100                 /* Check if the command matches any busybox internal commands
1101                  * ("applets") here.
1102                  * FIXME: This feature is not 100% safe, since
1103                  * BusyBox is not fully reentrant, so we have no guarantee the things
1104                  * from the .bss are still zeroed, or that things from .data are still
1105                  * at their defaults.  We could exec ourself from /proc/self/exe, but I
1106                  * really dislike relying on /proc for things.  We could exec ourself
1107                  * from global_argv[0], but if we are in a chroot, we may not be able
1108                  * to find ourself... */
1109 #ifdef CONFIG_FEATURE_SH_STANDALONE_SHELL
1110                 {
1111                         int argc_l;
1112                         char** argv_l=child->argv;
1113                         char *name = child->argv[0];
1114
1115                         /* Count argc for use in a second... */
1116                         for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1117                         optind = 1;
1118                         debug_printf("running applet %s\n", name);
1119                         run_applet_by_name(name, argc_l, child->argv);
1120                 }
1121 #endif
1122                 debug_printf("exec of %s\n",child->argv[0]);
1123                 execvp(child->argv[0],child->argv);
1124                 bb_perror_msg("cannot exec: %s",child->argv[0]);
1125                 _exit(1);
1126         } else if (child->group) {
1127                 debug_printf("runtime nesting to group\n");
1128                 interactive=0;    /* crucial!!!! */
1129                 rcode = run_list_real(child->group);
1130                 /* OK to leak memory by not calling free_pipe_list,
1131                  * since this process is about to exit */
1132                 _exit(rcode);
1133         } else {
1134                 /* Can happen.  See what bash does with ">foo" by itself. */
1135                 debug_printf("trying to pseudo_exec null command\n");
1136                 _exit(EXIT_SUCCESS);
1137         }
1138 }
1139
1140 static void insert_bg_job(struct pipe *pi)
1141 {
1142         struct pipe *thejob;
1143
1144         /* Linear search for the ID of the job to use */
1145         pi->jobid = 1;
1146         for (thejob = job_list; thejob; thejob = thejob->next)
1147                 if (thejob->jobid >= pi->jobid)
1148                         pi->jobid = thejob->jobid + 1;
1149
1150         /* add thejob to the list of running jobs */
1151         if (!job_list) {
1152                 thejob = job_list = xmalloc(sizeof(*thejob));
1153         } else {
1154                 for (thejob = job_list; thejob->next; thejob = thejob->next) /* nothing */;
1155                 thejob->next = xmalloc(sizeof(*thejob));
1156                 thejob = thejob->next;
1157         }
1158
1159         /* physically copy the struct job */
1160         memcpy(thejob, pi, sizeof(struct pipe));
1161         thejob->next = NULL;
1162         thejob->running_progs = thejob->num_progs;
1163         thejob->stopped_progs = 0;
1164         thejob->text = xmalloc(BUFSIZ); /* cmdedit buffer size */
1165
1166         //if (pi->progs[0] && pi->progs[0].argv && pi->progs[0].argv[0])
1167         {
1168                 char *bar=thejob->text;
1169                 char **foo=pi->progs[0].argv;
1170                 while(foo && *foo) {
1171                         bar += sprintf(bar, "%s ", *foo++);
1172                 }
1173         }
1174
1175         /* we don't wait for background thejobs to return -- append it
1176            to the list of backgrounded thejobs and leave it alone */
1177         printf("[%d] %d\n", thejob->jobid, thejob->progs[0].pid);
1178         last_bg_pid = thejob->progs[0].pid;
1179         last_jobid = thejob->jobid;
1180 }
1181
1182 /* remove a backgrounded job */
1183 static void remove_bg_job(struct pipe *pi)
1184 {
1185         struct pipe *prev_pipe;
1186
1187         if (pi == job_list) {
1188                 job_list = pi->next;
1189         } else {
1190                 prev_pipe = job_list;
1191                 while (prev_pipe->next != pi)
1192                         prev_pipe = prev_pipe->next;
1193                 prev_pipe->next = pi->next;
1194         }
1195         if (job_list)
1196                 last_jobid = job_list->jobid;
1197         else
1198                 last_jobid = 0;
1199
1200         pi->stopped_progs = 0;
1201         free_pipe(pi, 0);
1202         free(pi);
1203 }
1204
1205 /* Checks to see if any processes have exited -- if they
1206    have, figure out why and see if a job has completed */
1207 static int checkjobs(struct pipe* fg_pipe)
1208 {
1209         int attributes;
1210         int status;
1211         int prognum = 0;
1212         struct pipe *pi;
1213         pid_t childpid;
1214
1215         attributes = WUNTRACED;
1216         if (fg_pipe==NULL) {
1217                 attributes |= WNOHANG;
1218         }
1219
1220         while ((childpid = waitpid(-1, &status, attributes)) > 0) {
1221                 if (fg_pipe) {
1222                         int i, rcode = 0;
1223                         for (i=0; i < fg_pipe->num_progs; i++) {
1224                                 if (fg_pipe->progs[i].pid == childpid) {
1225                                         if (i==fg_pipe->num_progs-1)
1226                                                 rcode=WEXITSTATUS(status);
1227                                         (fg_pipe->num_progs)--;
1228                                         return rcode;
1229                                 }
1230                         }
1231                 }
1232
1233                 for (pi = job_list; pi; pi = pi->next) {
1234                         prognum = 0;
1235                         while (prognum < pi->num_progs && pi->progs[prognum].pid != childpid) {
1236                                 prognum++;
1237                         }
1238                         if (prognum < pi->num_progs)
1239                                 break;
1240                 }
1241
1242                 if(pi==NULL) {
1243                         debug_printf("checkjobs: pid %d was not in our list!\n", childpid);
1244                         continue;
1245                 }
1246
1247                 if (WIFEXITED(status) || WIFSIGNALED(status)) {
1248                         /* child exited */
1249                         pi->running_progs--;
1250                         pi->progs[prognum].pid = 0;
1251
1252                         if (!pi->running_progs) {
1253                                 printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->text);
1254                                 remove_bg_job(pi);
1255                         }
1256                 } else {
1257                         /* child stopped */
1258                         pi->stopped_progs++;
1259                         pi->progs[prognum].is_stopped = 1;
1260                 }
1261         }
1262
1263         if (childpid == -1 && errno != ECHILD)
1264                 bb_perror_msg("waitpid");
1265
1266         /* move the shell to the foreground */
1267         //if (interactive && tcsetpgrp(shell_terminal, getpgid(0)))
1268         //      bb_perror_msg("tcsetpgrp-2");
1269         return -1;
1270 }
1271
1272 /* run_pipe_real() starts all the jobs, but doesn't wait for anything
1273  * to finish.  See checkjobs().
1274  *
1275  * return code is normally -1, when the caller has to wait for children
1276  * to finish to determine the exit status of the pipe.  If the pipe
1277  * is a simple builtin command, however, the action is done by the
1278  * time run_pipe_real returns, and the exit code is provided as the
1279  * return value.
1280  *
1281  * The input of the pipe is always stdin, the output is always
1282  * stdout.  The outpipe[] mechanism in BusyBox-0.48 lash is bogus,
1283  * because it tries to avoid running the command substitution in
1284  * subshell, when that is in fact necessary.  The subshell process
1285  * now has its stdout directed to the input of the appropriate pipe,
1286  * so this routine is noticeably simpler.
1287  */
1288 static int run_pipe_real(struct pipe *pi)
1289 {
1290         int i;
1291         int nextin, nextout;
1292         int pipefds[2];                         /* pipefds[0] is for reading */
1293         struct child_prog *child;
1294         const struct built_in_command *x;
1295         char *p;
1296
1297         nextin = 0;
1298         pi->pgrp = -1;
1299
1300         /* Check if this is a simple builtin (not part of a pipe).
1301          * Builtins within pipes have to fork anyway, and are handled in
1302          * pseudo_exec.  "echo foo | read bar" doesn't work on bash, either.
1303          */
1304         child = & (pi->progs[0]);
1305         if (pi->num_progs == 1 && child->group && child->subshell == 0) {
1306                 int squirrel[] = {-1, -1, -1};
1307                 int rcode;
1308                 debug_printf("non-subshell grouping\n");
1309                 setup_redirects(child, squirrel);
1310                 /* XXX could we merge code with following builtin case,
1311                  * by creating a pseudo builtin that calls run_list_real? */
1312                 rcode = run_list_real(child->group);
1313                 restore_redirects(squirrel);
1314                 return rcode;
1315         } else if (pi->num_progs == 1 && pi->progs[0].argv != NULL) {
1316                 for (i=0; is_assignment(child->argv[i]); i++) { /* nothing */ }
1317                 if (i!=0 && child->argv[i]==NULL) {
1318                         /* assignments, but no command: set the local environment */
1319                         for (i=0; child->argv[i]!=NULL; i++) {
1320
1321                                 /* Ok, this case is tricky.  We have to decide if this is a
1322                                  * local variable, or an already exported variable.  If it is
1323                                  * already exported, we have to export the new value.  If it is
1324                                  * not exported, we need only set this as a local variable.
1325                                  * This junk is all to decide whether or not to export this
1326                                  * variable. */
1327                                 int export_me=0;
1328                                 char *name, *value;
1329                                 name = xstrdup(child->argv[i]);
1330                                 debug_printf("Local environment set: %s\n", name);
1331                                 value = strchr(name, '=');
1332                                 if (value)
1333                                         *value=0;
1334                                 if ( get_local_var(name)) {
1335                                         export_me=1;
1336                                 }
1337                                 free(name);
1338                                 p = insert_var_value(child->argv[i]);
1339                                 set_local_var(p, export_me);
1340                                 if (p != child->argv[i]) free(p);
1341                         }
1342                         return EXIT_SUCCESS;   /* don't worry about errors in set_local_var() yet */
1343                 }
1344                 for (i = 0; is_assignment(child->argv[i]); i++) {
1345                         p = insert_var_value(child->argv[i]);
1346                         putenv(strdup(p));
1347                         if (p != child->argv[i]) {
1348                                 child->sp--;
1349                                 free(p);
1350                         }
1351                 }
1352                 if (child->sp) {
1353                         char * str = NULL;
1354
1355                         str = make_string((child->argv + i));
1356                         parse_string_outer(str, FLAG_EXIT_FROM_LOOP | FLAG_REPARSING);
1357                         free(str);
1358                         return last_return_code;
1359                 }
1360                 for (x = bltins; x->cmd; x++) {
1361                         if (strcmp(child->argv[i], x->cmd) == 0 ) {
1362                                 int squirrel[] = {-1, -1, -1};
1363                                 int rcode;
1364                                 if (x->function == builtin_exec && child->argv[i+1]==NULL) {
1365                                         debug_printf("magic exec\n");
1366                                         setup_redirects(child,NULL);
1367                                         return EXIT_SUCCESS;
1368                                 }
1369                                 debug_printf("builtin inline %s\n", child->argv[0]);
1370                                 /* XXX setup_redirects acts on file descriptors, not FILEs.
1371                                  * This is perfect for work that comes after exec().
1372                                  * Is it really safe for inline use?  Experimentally,
1373                                  * things seem to work with glibc. */
1374                                 setup_redirects(child, squirrel);
1375                                 child->argv+=i;  /* XXX horrible hack */
1376                                 rcode = x->function(child);
1377                                 child->argv-=i;  /* XXX restore hack so free() can work right */
1378                                 restore_redirects(squirrel);
1379                                 return rcode;
1380                         }
1381                 }
1382         }
1383
1384         for (i = 0; i < pi->num_progs; i++) {
1385                 child = & (pi->progs[i]);
1386
1387                 /* pipes are inserted between pairs of commands */
1388                 if ((i + 1) < pi->num_progs) {
1389                         if (pipe(pipefds)<0) bb_perror_msg_and_die("pipe");
1390                         nextout = pipefds[1];
1391                 } else {
1392                         nextout=1;
1393                         pipefds[0] = -1;
1394                 }
1395
1396                 /* XXX test for failed fork()? */
1397 #if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
1398                 if (!(child->pid = fork()))
1399 #else
1400                 if (!(child->pid = vfork()))
1401 #endif
1402                 {
1403                         /* Set the handling for job control signals back to the default.  */
1404                         signal(SIGINT, SIG_DFL);
1405                         signal(SIGQUIT, SIG_DFL);
1406                         signal(SIGTERM, SIG_DFL);
1407                         signal(SIGTSTP, SIG_DFL);
1408                         signal(SIGTTIN, SIG_DFL);
1409                         signal(SIGTTOU, SIG_DFL);
1410                         signal(SIGCHLD, SIG_DFL);
1411
1412                         close_all();
1413
1414                         if (nextin != 0) {
1415                                 dup2(nextin, 0);
1416                                 close(nextin);
1417                         }
1418                         if (nextout != 1) {
1419                                 dup2(nextout, 1);
1420                                 close(nextout);
1421                         }
1422                         if (pipefds[0]!=-1) {
1423                                 close(pipefds[0]);  /* opposite end of our output pipe */
1424                         }
1425
1426                         /* Like bash, explicit redirects override pipes,
1427                          * and the pipe fd is available for dup'ing. */
1428                         setup_redirects(child,NULL);
1429
1430                         if (interactive && pi->followup!=PIPE_BG) {
1431                                 /* If we (the child) win the race, put ourselves in the process
1432                                  * group whose leader is the first process in this pipe. */
1433                                 if (pi->pgrp < 0) {
1434                                         pi->pgrp = getpid();
1435                                 }
1436                                 if (setpgid(0, pi->pgrp) == 0) {
1437                                         tcsetpgrp(2, pi->pgrp);
1438                                 }
1439                         }
1440
1441                         pseudo_exec(child);
1442                 }
1443
1444
1445                 /* put our child in the process group whose leader is the
1446                    first process in this pipe */
1447                 if (pi->pgrp < 0) {
1448                         pi->pgrp = child->pid;
1449                 }
1450                 /* Don't check for errors.  The child may be dead already,
1451                  * in which case setpgid returns error code EACCES. */
1452                 setpgid(child->pid, pi->pgrp);
1453
1454                 if (nextin != 0)
1455                         close(nextin);
1456                 if (nextout != 1)
1457                         close(nextout);
1458
1459                 /* If there isn't another process, nextin is garbage
1460                    but it doesn't matter */
1461                 nextin = pipefds[0];
1462         }
1463         return -1;
1464 }
1465
1466 static int run_list_real(struct pipe *pi)
1467 {
1468         char *save_name = NULL;
1469         char **list = NULL;
1470         char **save_list = NULL;
1471         struct pipe *rpipe;
1472         int flag_rep = 0;
1473         int save_num_progs;
1474         int rcode=0, flag_skip=1;
1475         int flag_restore = 0;
1476         int if_code=0, next_if_code=0;  /* need double-buffer to handle elif */
1477         reserved_style rmode, skip_more_in_this_rmode=RES_XXXX;
1478         /* check syntax for "for" */
1479         for (rpipe = pi; rpipe; rpipe = rpipe->next) {
1480                 if ((rpipe->r_mode == RES_IN ||
1481                     rpipe->r_mode == RES_FOR) &&
1482                     (rpipe->next == NULL)) {
1483                                 syntax();
1484                                 return 1;
1485                 }
1486                 if ((rpipe->r_mode == RES_IN &&
1487                         (rpipe->next->r_mode == RES_IN &&
1488                         rpipe->next->progs->argv != NULL))||
1489                         (rpipe->r_mode == RES_FOR &&
1490                         rpipe->next->r_mode != RES_IN)) {
1491                                 syntax();
1492                                 return 1;
1493                 }
1494         }
1495         for (; pi; pi = (flag_restore != 0) ? rpipe : pi->next) {
1496                 if (pi->r_mode == RES_WHILE || pi->r_mode == RES_UNTIL ||
1497                         pi->r_mode == RES_FOR) {
1498                                 flag_restore = 0;
1499                                 if (!rpipe) {
1500                                         flag_rep = 0;
1501                                         rpipe = pi;
1502                                 }
1503                 }
1504                 rmode = pi->r_mode;
1505                 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);
1506                 if (rmode == skip_more_in_this_rmode && flag_skip) {
1507                         if (pi->followup == PIPE_SEQ) flag_skip=0;
1508                         continue;
1509                 }
1510                 flag_skip = 1;
1511                 skip_more_in_this_rmode = RES_XXXX;
1512                 if (rmode == RES_THEN || rmode == RES_ELSE) if_code = next_if_code;
1513                 if (rmode == RES_THEN &&  if_code) continue;
1514                 if (rmode == RES_ELSE && !if_code) continue;
1515                 if (rmode == RES_ELIF && !if_code) break;
1516                 if (rmode == RES_FOR && pi->num_progs) {
1517                         if (!list) {
1518                                 /* if no variable values after "in" we skip "for" */
1519                                 if (!pi->next->progs->argv) continue;
1520                                 /* create list of variable values */
1521                                 list = make_list_in(pi->next->progs->argv,
1522                                         pi->progs->argv[0]);
1523                                 save_list = list;
1524                                 save_name = pi->progs->argv[0];
1525                                 pi->progs->argv[0] = NULL;
1526                                 flag_rep = 1;
1527                         }
1528                         if (!(*list)) {
1529                                 free(pi->progs->argv[0]);
1530                                 free(save_list);
1531                                 list = NULL;
1532                                 flag_rep = 0;
1533                                 pi->progs->argv[0] = save_name;
1534                                 pi->progs->glob_result.gl_pathv[0] =
1535                                         pi->progs->argv[0];
1536                                 continue;
1537                         } else {
1538                                 /* insert new value from list for variable */
1539                                 if (pi->progs->argv[0])
1540                                         free(pi->progs->argv[0]);
1541                                 pi->progs->argv[0] = *list++;
1542                                 pi->progs->glob_result.gl_pathv[0] =
1543                                         pi->progs->argv[0];
1544                         }
1545                 }
1546                 if (rmode == RES_IN) continue;
1547                 if (rmode == RES_DO) {
1548                         if (!flag_rep) continue;
1549                 }
1550                 if ((rmode == RES_DONE)) {
1551                         if (flag_rep) {
1552                                 flag_restore = 1;
1553                         } else {
1554                                 rpipe = NULL;
1555                         }
1556                 }
1557                 if (pi->num_progs == 0) continue;
1558                 save_num_progs = pi->num_progs; /* save number of programs */
1559                 rcode = run_pipe_real(pi);
1560                 debug_printf("run_pipe_real returned %d\n",rcode);
1561                 if (rcode!=-1) {
1562                         /* We only ran a builtin: rcode was set by the return value
1563                          * of run_pipe_real(), and we don't need to wait for anything. */
1564                 } else if (pi->followup==PIPE_BG) {
1565                         /* XXX check bash's behavior with nontrivial pipes */
1566                         /* XXX compute jobid */
1567                         /* XXX what does bash do with attempts to background builtins? */
1568                         insert_bg_job(pi);
1569                         rcode = EXIT_SUCCESS;
1570                 } else {
1571                         if (interactive) {
1572                                 /* move the new process group into the foreground */
1573                                 if (tcsetpgrp(shell_terminal, pi->pgrp) && errno != ENOTTY)
1574                                         bb_perror_msg("tcsetpgrp-3");
1575                                 rcode = checkjobs(pi);
1576                                 /* move the shell to the foreground */
1577                                 if (tcsetpgrp(shell_terminal, getpgid(0)) && errno != ENOTTY)
1578                                         bb_perror_msg("tcsetpgrp-4");
1579                         } else {
1580                                 rcode = checkjobs(pi);
1581                         }
1582                         debug_printf("checkjobs returned %d\n",rcode);
1583                 }
1584                 last_return_code=rcode;
1585                 pi->num_progs = save_num_progs; /* restore number of programs */
1586                 if ( rmode == RES_IF || rmode == RES_ELIF )
1587                         next_if_code=rcode;  /* can be overwritten a number of times */
1588                 if (rmode == RES_WHILE)
1589                         flag_rep = !last_return_code;
1590                 if (rmode == RES_UNTIL)
1591                         flag_rep = last_return_code;
1592                 if ( (rcode==EXIT_SUCCESS && pi->followup==PIPE_OR) ||
1593                      (rcode!=EXIT_SUCCESS && pi->followup==PIPE_AND) )
1594                         skip_more_in_this_rmode=rmode;
1595                 checkjobs(NULL);
1596         }
1597         return rcode;
1598 }
1599
1600 /* return code is the exit status of the pipe */
1601 static int free_pipe(struct pipe *pi, int indent)
1602 {
1603         char **p;
1604         struct child_prog *child;
1605         struct redir_struct *r, *rnext;
1606         int a, i, ret_code=0;
1607
1608         if (pi->stopped_progs > 0)
1609                 return ret_code;
1610         final_printf("%s run pipe: (pid %d)\n",indenter(indent),getpid());
1611         for (i=0; i<pi->num_progs; i++) {
1612                 child = &pi->progs[i];
1613                 final_printf("%s  command %d:\n",indenter(indent),i);
1614                 if (child->argv) {
1615                         for (a=0,p=child->argv; *p; a++,p++) {
1616                                 final_printf("%s   argv[%d] = %s\n",indenter(indent),a,*p);
1617                         }
1618                         globfree(&child->glob_result);
1619                         child->argv=NULL;
1620                 } else if (child->group) {
1621                         final_printf("%s   begin group (subshell:%d)\n",indenter(indent), child->subshell);
1622                         ret_code = free_pipe_list(child->group,indent+3);
1623                         final_printf("%s   end group\n",indenter(indent));
1624                 } else {
1625                         final_printf("%s   (nil)\n",indenter(indent));
1626                 }
1627                 for (r=child->redirects; r; r=rnext) {
1628                         final_printf("%s   redirect %d%s", indenter(indent), r->fd, redir_table[r->type].descrip);
1629                         if (r->dup == -1) {
1630                                 /* guard against the case >$FOO, where foo is unset or blank */
1631                                 if (r->word.gl_pathv) {
1632                                         final_printf(" %s\n", *r->word.gl_pathv);
1633                                         globfree(&r->word);
1634                                 }
1635                         } else {
1636                                 final_printf("&%d\n", r->dup);
1637                         }
1638                         rnext=r->next;
1639                         free(r);
1640                 }
1641                 child->redirects=NULL;
1642         }
1643         free(pi->progs);   /* children are an array, they get freed all at once */
1644         pi->progs=NULL;
1645         return ret_code;
1646 }
1647
1648 static int free_pipe_list(struct pipe *head, int indent)
1649 {
1650         int rcode=0;   /* if list has no members */
1651         struct pipe *pi, *next;
1652         for (pi=head; pi; pi=next) {
1653                 final_printf("%s pipe reserved mode %d\n", indenter(indent), pi->r_mode);
1654                 rcode = free_pipe(pi, indent);
1655                 final_printf("%s pipe followup code %d\n", indenter(indent), pi->followup);
1656                 next=pi->next;
1657                 pi->next=NULL;
1658                 free(pi);
1659         }
1660         return rcode;
1661 }
1662
1663 /* Select which version we will use */
1664 static int run_list(struct pipe *pi)
1665 {
1666         int rcode=0;
1667         if (fake_mode==0) {
1668                 rcode = run_list_real(pi);
1669         }
1670         /* free_pipe_list has the side effect of clearing memory
1671          * In the long run that function can be merged with run_list_real,
1672          * but doing that now would hobble the debugging effort. */
1673         free_pipe_list(pi,0);
1674         return rcode;
1675 }
1676
1677 /* The API for glob is arguably broken.  This routine pushes a non-matching
1678  * string into the output structure, removing non-backslashed backslashes.
1679  * If someone can prove me wrong, by performing this function within the
1680  * original glob(3) api, feel free to rewrite this routine into oblivion.
1681  * Return code (0 vs. GLOB_NOSPACE) matches glob(3).
1682  * XXX broken if the last character is '\\', check that before calling.
1683  */
1684 static int globhack(const char *src, int flags, glob_t *pglob)
1685 {
1686         int cnt=0, pathc;
1687         const char *s;
1688         char *dest;
1689         for (cnt=1, s=src; s && *s; s++) {
1690                 if (*s == '\\') s++;
1691                 cnt++;
1692         }
1693         dest = malloc(cnt);
1694         if (!dest) return GLOB_NOSPACE;
1695         if (!(flags & GLOB_APPEND)) {
1696                 pglob->gl_pathv=NULL;
1697                 pglob->gl_pathc=0;
1698                 pglob->gl_offs=0;
1699                 pglob->gl_offs=0;
1700         }
1701         pathc = ++pglob->gl_pathc;
1702         pglob->gl_pathv = realloc(pglob->gl_pathv, (pathc+1)*sizeof(*pglob->gl_pathv));
1703         if (pglob->gl_pathv == NULL) return GLOB_NOSPACE;
1704         pglob->gl_pathv[pathc-1]=dest;
1705         pglob->gl_pathv[pathc]=NULL;
1706         for (s=src; s && *s; s++, dest++) {
1707                 if (*s == '\\') s++;
1708                 *dest = *s;
1709         }
1710         *dest='\0';
1711         return 0;
1712 }
1713
1714 /* XXX broken if the last character is '\\', check that before calling */
1715 static int glob_needed(const char *s)
1716 {
1717         for (; *s; s++) {
1718                 if (*s == '\\') s++;
1719                 if (strchr("*[?",*s)) return 1;
1720         }
1721         return 0;
1722 }
1723
1724 static int xglob(o_string *dest, int flags, glob_t *pglob)
1725 {
1726         int gr;
1727
1728         /* short-circuit for null word */
1729         /* we can code this better when the debug_printf's are gone */
1730         if (dest->length == 0) {
1731                 if (dest->nonnull) {
1732                         /* bash man page calls this an "explicit" null */
1733                         gr = globhack(dest->data, flags, pglob);
1734                         debug_printf("globhack returned %d\n",gr);
1735                 } else {
1736                         return 0;
1737                 }
1738         } else if (glob_needed(dest->data)) {
1739                 gr = glob(dest->data, flags, NULL, pglob);
1740                 debug_printf("glob returned %d\n",gr);
1741                 if (gr == GLOB_NOMATCH) {
1742                         /* quote removal, or more accurately, backslash removal */
1743                         gr = globhack(dest->data, flags, pglob);
1744                         debug_printf("globhack returned %d\n",gr);
1745                 }
1746         } else {
1747                 gr = globhack(dest->data, flags, pglob);
1748                 debug_printf("globhack returned %d\n",gr);
1749         }
1750         if (gr == GLOB_NOSPACE)
1751                 bb_error_msg_and_die("out of memory during glob");
1752         if (gr != 0) { /* GLOB_ABORTED ? */
1753                 bb_error_msg("glob(3) error %d",gr);
1754         }
1755         /* globprint(glob_target); */
1756         return gr;
1757 }
1758
1759 /* This is used to get/check local shell variables */
1760 static char *get_local_var(const char *s)
1761 {
1762         struct variables *cur;
1763
1764         if (!s)
1765                 return NULL;
1766         for (cur = top_vars; cur; cur=cur->next)
1767                 if(strcmp(cur->name, s)==0)
1768                         return cur->value;
1769         return NULL;
1770 }
1771
1772 /* This is used to set local shell variables
1773    flg_export==0 if only local (not exporting) variable
1774    flg_export==1 if "new" exporting environ
1775    flg_export>1  if current startup environ (not call putenv()) */
1776 static int set_local_var(const char *s, int flg_export)
1777 {
1778         char *name, *value;
1779         int result=0;
1780         struct variables *cur;
1781
1782         name=strdup(s);
1783
1784         /* Assume when we enter this function that we are already in
1785          * NAME=VALUE format.  So the first order of business is to
1786          * split 's' on the '=' into 'name' and 'value' */
1787         value = strchr(name, '=');
1788         if (value==0 && ++value==0) {
1789                 free(name);
1790                 return -1;
1791         }
1792         *value++ = 0;
1793
1794         for(cur = top_vars; cur; cur = cur->next) {
1795                 if(strcmp(cur->name, name)==0)
1796                         break;
1797         }
1798
1799         if(cur) {
1800                 if(strcmp(cur->value, value)==0) {
1801                         if(flg_export>0 && cur->flg_export==0)
1802                                 cur->flg_export=flg_export;
1803                         else
1804                                 result++;
1805                 } else {
1806                         if(cur->flg_read_only) {
1807                                 bb_error_msg("%s: readonly variable", name);
1808                                 result = -1;
1809                         } else {
1810                                 if(flg_export>0 || cur->flg_export>1)
1811                                         cur->flg_export=1;
1812                                 free(cur->value);
1813
1814                                 cur->value = strdup(value);
1815                         }
1816                 }
1817         } else {
1818                 cur = malloc(sizeof(struct variables));
1819                 if(!cur) {
1820                         result = -1;
1821                 } else {
1822                         cur->name = strdup(name);
1823                         if(cur->name == 0) {
1824                                 free(cur);
1825                                 result = -1;
1826                         } else {
1827                                 struct variables *bottom = top_vars;
1828                                 cur->value = strdup(value);
1829                                 cur->next = 0;
1830                                 cur->flg_export = flg_export;
1831                                 cur->flg_read_only = 0;
1832                                 while(bottom->next) bottom=bottom->next;
1833                                 bottom->next = cur;
1834                         }
1835                 }
1836         }
1837
1838         if(result==0 && cur->flg_export==1) {
1839                 *(value-1) = '=';
1840                 result = putenv(name);
1841         } else {
1842                 free(name);
1843                 if(result>0)            /* equivalent to previous set */
1844                         result = 0;
1845         }
1846         return result;
1847 }
1848
1849 static void unset_local_var(const char *name)
1850 {
1851         struct variables *cur;
1852
1853         if (name) {
1854                 for (cur = top_vars; cur; cur=cur->next) {
1855                         if(strcmp(cur->name, name)==0)
1856                                 break;
1857                 }
1858                 if(cur!=0) {
1859                         struct variables *next = top_vars;
1860                         if(cur->flg_read_only) {
1861                                 bb_error_msg("%s: readonly variable", name);
1862                                 return;
1863                         } else {
1864                                 if(cur->flg_export)
1865                                         unsetenv(cur->name);
1866                                 free(cur->name);
1867                                 free(cur->value);
1868                                 while (next->next != cur)
1869                                         next = next->next;
1870                                 next->next = cur->next;
1871                         }
1872                         free(cur);
1873                 }
1874         }
1875 }
1876
1877 static int is_assignment(const char *s)
1878 {
1879         if (s==NULL || !isalpha(*s)) return 0;
1880         ++s;
1881         while(isalnum(*s) || *s=='_') ++s;
1882         return *s=='=';
1883 }
1884
1885 /* the src parameter allows us to peek forward to a possible &n syntax
1886  * for file descriptor duplication, e.g., "2>&1".
1887  * Return code is 0 normally, 1 if a syntax error is detected in src.
1888  * Resource errors (in xmalloc) cause the process to exit */
1889 static int setup_redirect(struct p_context *ctx, int fd, redir_type style,
1890         struct in_str *input)
1891 {
1892         struct child_prog *child=ctx->child;
1893         struct redir_struct *redir = child->redirects;
1894         struct redir_struct *last_redir=NULL;
1895
1896         /* Create a new redir_struct and drop it onto the end of the linked list */
1897         while(redir) {
1898                 last_redir=redir;
1899                 redir=redir->next;
1900         }
1901         redir = xmalloc(sizeof(struct redir_struct));
1902         redir->next=NULL;
1903         redir->word.gl_pathv=NULL;
1904         if (last_redir) {
1905                 last_redir->next=redir;
1906         } else {
1907                 child->redirects=redir;
1908         }
1909
1910         redir->type=style;
1911         redir->fd= (fd==-1) ? redir_table[style].default_fd : fd ;
1912
1913         debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip);
1914
1915         /* Check for a '2>&1' type redirect */
1916         redir->dup = redirect_dup_num(input);
1917         if (redir->dup == -2) return 1;  /* syntax error */
1918         if (redir->dup != -1) {
1919                 /* Erik had a check here that the file descriptor in question
1920                  * is legit; I postpone that to "run time"
1921                  * A "-" representation of "close me" shows up as a -3 here */
1922                 debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup);
1923         } else {
1924                 /* We do _not_ try to open the file that src points to,
1925                  * since we need to return and let src be expanded first.
1926                  * Set ctx->pending_redirect, so we know what to do at the
1927                  * end of the next parsed word.
1928                  */
1929                 ctx->pending_redirect = redir;
1930         }
1931         return 0;
1932 }
1933
1934 static struct pipe *new_pipe(void) {
1935         struct pipe *pi;
1936         pi = xmalloc(sizeof(struct pipe));
1937         pi->num_progs = 0;
1938         pi->progs = NULL;
1939         pi->next = NULL;
1940         pi->followup = 0;  /* invalid */
1941         pi->r_mode = RES_NONE;
1942         return pi;
1943 }
1944
1945 static void initialize_context(struct p_context *ctx)
1946 {
1947         ctx->pipe=NULL;
1948         ctx->pending_redirect=NULL;
1949         ctx->child=NULL;
1950         ctx->list_head=new_pipe();
1951         ctx->pipe=ctx->list_head;
1952         ctx->w=RES_NONE;
1953         ctx->stack=NULL;
1954         ctx->old_flag=0;
1955         done_command(ctx);   /* creates the memory for working child */
1956 }
1957
1958 /* normal return is 0
1959  * if a reserved word is found, and processed, return 1
1960  * should handle if, then, elif, else, fi, for, while, until, do, done.
1961  * case, function, and select are obnoxious, save those for later.
1962  */
1963 static int reserved_word(o_string *dest, struct p_context *ctx)
1964 {
1965         struct reserved_combo {
1966                 char *literal;
1967                 int code;
1968                 long flag;
1969         };
1970         /* Mostly a list of accepted follow-up reserved words.
1971          * FLAG_END means we are done with the sequence, and are ready
1972          * to turn the compound list into a command.
1973          * FLAG_START means the word must start a new compound list.
1974          */
1975         static struct reserved_combo reserved_list[] = {
1976                 { "if",    RES_IF,    FLAG_THEN | FLAG_START },
1977                 { "then",  RES_THEN,  FLAG_ELIF | FLAG_ELSE | FLAG_FI },
1978                 { "elif",  RES_ELIF,  FLAG_THEN },
1979                 { "else",  RES_ELSE,  FLAG_FI   },
1980                 { "fi",    RES_FI,    FLAG_END  },
1981                 { "for",   RES_FOR,   FLAG_IN   | FLAG_START },
1982                 { "while", RES_WHILE, FLAG_DO   | FLAG_START },
1983                 { "until", RES_UNTIL, FLAG_DO   | FLAG_START },
1984                 { "in",    RES_IN,    FLAG_DO   },
1985                 { "do",    RES_DO,    FLAG_DONE },
1986                 { "done",  RES_DONE,  FLAG_END  }
1987         };
1988         struct reserved_combo *r;
1989         for (r=reserved_list;
1990 #define NRES sizeof(reserved_list)/sizeof(struct reserved_combo)
1991                 r<reserved_list+NRES; r++) {
1992                 if (strcmp(dest->data, r->literal) == 0) {
1993                         debug_printf("found reserved word %s, code %d\n",r->literal,r->code);
1994                         if (r->flag & FLAG_START) {
1995                                 struct p_context *new = xmalloc(sizeof(struct p_context));
1996                                 debug_printf("push stack\n");
1997                                 if (ctx->w == RES_IN || ctx->w == RES_FOR) {
1998                                         syntax();
1999                                         free(new);
2000                                         ctx->w = RES_SNTX;
2001                                         b_reset(dest);
2002                                         return 1;
2003                                 }
2004                                 *new = *ctx;   /* physical copy */
2005                                 initialize_context(ctx);
2006                                 ctx->stack=new;
2007                         } else if ( ctx->w == RES_NONE || ! (ctx->old_flag & (1<<r->code))) {
2008                                 syntax();
2009                                 ctx->w = RES_SNTX;
2010                                 b_reset(dest);
2011                                 return 1;
2012                         }
2013                         ctx->w=r->code;
2014                         ctx->old_flag = r->flag;
2015                         if (ctx->old_flag & FLAG_END) {
2016                                 struct p_context *old;
2017                                 debug_printf("pop stack\n");
2018                                 done_pipe(ctx,PIPE_SEQ);
2019                                 old = ctx->stack;
2020                                 old->child->group = ctx->list_head;
2021                                 old->child->subshell = 0;
2022                                 *ctx = *old;   /* physical copy */
2023                                 free(old);
2024                         }
2025                         b_reset (dest);
2026                         return 1;
2027                 }
2028         }
2029         return 0;
2030 }
2031
2032 /* normal return is 0.
2033  * Syntax or xglob errors return 1. */
2034 static int done_word(o_string *dest, struct p_context *ctx)
2035 {
2036         struct child_prog *child=ctx->child;
2037         glob_t *glob_target;
2038         int gr, flags = 0;
2039
2040         debug_printf("done_word: %s %p\n", dest->data, child);
2041         if (dest->length == 0 && !dest->nonnull) {
2042                 debug_printf("  true null, ignored\n");
2043                 return 0;
2044         }
2045         if (ctx->pending_redirect) {
2046                 glob_target = &ctx->pending_redirect->word;
2047         } else {
2048                 if (child->group) {
2049                         syntax();
2050                         return 1;  /* syntax error, groups and arglists don't mix */
2051                 }
2052                 if (!child->argv && (ctx->type & FLAG_PARSE_SEMICOLON)) {
2053                         debug_printf("checking %s for reserved-ness\n",dest->data);
2054                         if (reserved_word(dest,ctx)) return ctx->w==RES_SNTX;
2055                 }
2056                 glob_target = &child->glob_result;
2057                 if (child->argv) flags |= GLOB_APPEND;
2058         }
2059         gr = xglob(dest, flags, glob_target);
2060         if (gr != 0) return 1;
2061
2062         b_reset(dest);
2063         if (ctx->pending_redirect) {
2064                 ctx->pending_redirect=NULL;
2065                 if (glob_target->gl_pathc != 1) {
2066                         bb_error_msg("ambiguous redirect");
2067                         return 1;
2068                 }
2069         } else {
2070                 child->argv = glob_target->gl_pathv;
2071         }
2072         if (ctx->w == RES_FOR) {
2073                 done_word(dest,ctx);
2074                 done_pipe(ctx,PIPE_SEQ);
2075         }
2076         return 0;
2077 }
2078
2079 /* The only possible error here is out of memory, in which case
2080  * xmalloc exits. */
2081 static int done_command(struct p_context *ctx)
2082 {
2083         /* The child is really already in the pipe structure, so
2084          * advance the pipe counter and make a new, null child.
2085          * Only real trickiness here is that the uncommitted
2086          * child structure, to which ctx->child points, is not
2087          * counted in pi->num_progs. */
2088         struct pipe *pi=ctx->pipe;
2089         struct child_prog *prog=ctx->child;
2090
2091         if (prog && prog->group == NULL
2092                  && prog->argv == NULL
2093                  && prog->redirects == NULL) {
2094                 debug_printf("done_command: skipping null command\n");
2095                 return 0;
2096         } else if (prog) {
2097                 pi->num_progs++;
2098                 debug_printf("done_command: num_progs incremented to %d\n",pi->num_progs);
2099         } else {
2100                 debug_printf("done_command: initializing\n");
2101         }
2102         pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1));
2103
2104         prog = pi->progs + pi->num_progs;
2105         prog->redirects = NULL;
2106         prog->argv = NULL;
2107         prog->is_stopped = 0;
2108         prog->group = NULL;
2109         prog->glob_result.gl_pathv = NULL;
2110         prog->family = pi;
2111         prog->sp = 0;
2112         ctx->child = prog;
2113         prog->type = ctx->type;
2114
2115         /* but ctx->pipe and ctx->list_head remain unchanged */
2116         return 0;
2117 }
2118
2119 static int done_pipe(struct p_context *ctx, pipe_style type)
2120 {
2121         struct pipe *new_p;
2122         done_command(ctx);  /* implicit closure of previous command */
2123         debug_printf("done_pipe, type %d\n", type);
2124         ctx->pipe->followup = type;
2125         ctx->pipe->r_mode = ctx->w;
2126         new_p=new_pipe();
2127         ctx->pipe->next = new_p;
2128         ctx->pipe = new_p;
2129         ctx->child = NULL;
2130         done_command(ctx);  /* set up new pipe to accept commands */
2131         return 0;
2132 }
2133
2134 /* peek ahead in the in_str to find out if we have a "&n" construct,
2135  * as in "2>&1", that represents duplicating a file descriptor.
2136  * returns either -2 (syntax error), -1 (no &), or the number found.
2137  */
2138 static int redirect_dup_num(struct in_str *input)
2139 {
2140         int ch, d=0, ok=0;
2141         ch = b_peek(input);
2142         if (ch != '&') return -1;
2143
2144         b_getch(input);  /* get the & */
2145         ch=b_peek(input);
2146         if (ch == '-') {
2147                 b_getch(input);
2148                 return -3;  /* "-" represents "close me" */
2149         }
2150         while (isdigit(ch)) {
2151                 d = d*10+(ch-'0');
2152                 ok=1;
2153                 b_getch(input);
2154                 ch = b_peek(input);
2155         }
2156         if (ok) return d;
2157
2158         bb_error_msg("ambiguous redirect");
2159         return -2;
2160 }
2161
2162 /* If a redirect is immediately preceded by a number, that number is
2163  * supposed to tell which file descriptor to redirect.  This routine
2164  * looks for such preceding numbers.  In an ideal world this routine
2165  * needs to handle all the following classes of redirects...
2166  *     echo 2>foo     # redirects fd  2 to file "foo", nothing passed to echo
2167  *     echo 49>foo    # redirects fd 49 to file "foo", nothing passed to echo
2168  *     echo -2>foo    # redirects fd  1 to file "foo",    "-2" passed to echo
2169  *     echo 49x>foo   # redirects fd  1 to file "foo",   "49x" passed to echo
2170  * A -1 output from this program means no valid number was found, so the
2171  * caller should use the appropriate default for this redirection.
2172  */
2173 static int redirect_opt_num(o_string *o)
2174 {
2175         int num;
2176
2177         if (o->length==0) return -1;
2178         for(num=0; num<o->length; num++) {
2179                 if (!isdigit(*(o->data+num))) {
2180                         return -1;
2181                 }
2182         }
2183         /* reuse num (and save an int) */
2184         num=atoi(o->data);
2185         b_reset(o);
2186         return num;
2187 }
2188
2189 static FILE *generate_stream_from_list(struct pipe *head)
2190 {
2191         FILE *pf;
2192         int pid, channel[2];
2193         if (pipe(channel)<0) bb_perror_msg_and_die("pipe");
2194 #if !defined(__UCLIBC__) || defined(__ARCH_HAS_MMU__)
2195         pid=fork();
2196 #else
2197         pid=vfork();
2198 #endif
2199         if (pid<0) {
2200                 bb_perror_msg_and_die("fork");
2201         } else if (pid==0) {
2202                 close(channel[0]);
2203                 if (channel[1] != 1) {
2204                         dup2(channel[1],1);
2205                         close(channel[1]);
2206                 }
2207                 _exit(run_list_real(head));   /* leaks memory */
2208         }
2209         debug_printf("forked child %d\n",pid);
2210         close(channel[1]);
2211         pf = fdopen(channel[0],"r");
2212         debug_printf("pipe on FILE *%p\n",pf);
2213         return pf;
2214 }
2215
2216 /* this version hacked for testing purposes */
2217 /* return code is exit status of the process that is run. */
2218 static int process_command_subs(o_string *dest, struct p_context *ctx, struct in_str *input, int subst_end)
2219 {
2220         int retcode;
2221         o_string result=NULL_O_STRING;
2222         struct p_context inner;
2223         FILE *p;
2224         struct in_str pipe_str;
2225         initialize_context(&inner);
2226
2227         /* recursion to generate command */
2228         retcode = parse_stream(&result, &inner, input, subst_end);
2229         if (retcode != 0) return retcode;  /* syntax error or EOF */
2230         done_word(&result, &inner);
2231         done_pipe(&inner, PIPE_SEQ);
2232         b_free(&result);
2233
2234         p=generate_stream_from_list(inner.list_head);
2235         if (p==NULL) return 1;
2236         mark_open(fileno(p));
2237         setup_file_in_str(&pipe_str, p);
2238
2239         /* now send results of command back into original context */
2240         retcode = parse_stream(dest, ctx, &pipe_str, '\0');
2241         /* XXX In case of a syntax error, should we try to kill the child?
2242          * That would be tough to do right, so just read until EOF. */
2243         if (retcode == 1) {
2244                 while (b_getch(&pipe_str)!=EOF) { /* discard */ };
2245         }
2246
2247         debug_printf("done reading from pipe, pclose()ing\n");
2248         /* This is the step that wait()s for the child.  Should be pretty
2249          * safe, since we just read an EOF from its stdout.  We could try
2250          * to better, by using wait(), and keeping track of background jobs
2251          * at the same time.  That would be a lot of work, and contrary
2252          * to the KISS philosophy of this program. */
2253         mark_closed(fileno(p));
2254         retcode=pclose(p);
2255         free_pipe_list(inner.list_head,0);
2256         debug_printf("pclosed, retcode=%d\n",retcode);
2257         /* XXX this process fails to trim a single trailing newline */
2258         return retcode;
2259 }
2260
2261 static int parse_group(o_string *dest, struct p_context *ctx,
2262         struct in_str *input, int ch)
2263 {
2264         int rcode, endch=0;
2265         struct p_context sub;
2266         struct child_prog *child = ctx->child;
2267         if (child->argv) {
2268                 syntax();
2269                 return 1;  /* syntax error, groups and arglists don't mix */
2270         }
2271         initialize_context(&sub);
2272         switch (ch) {
2273                 case '(': endch=')'; child->subshell=1; break;
2274                 case '{': endch='}'; break;
2275                 default: syntax();   /* really logic error */
2276         }
2277         rcode=parse_stream(dest,&sub,input,endch);
2278         done_word(dest,&sub); /* finish off the final word in the subcontext */
2279         done_pipe(&sub, PIPE_SEQ);  /* and the final command there, too */
2280         child->group = sub.list_head;
2281         return rcode;
2282         /* child remains "open", available for possible redirects */
2283 }
2284
2285 /* basically useful version until someone wants to get fancier,
2286  * see the bash man page under "Parameter Expansion" */
2287 static char *lookup_param(char *src)
2288 {
2289         char *p=NULL;
2290         if (src) {
2291                 p = getenv(src);
2292                 if (!p)
2293                         p = get_local_var(src);
2294         }
2295         return p;
2296 }
2297
2298 /* return code: 0 for OK, 1 for syntax error */
2299 static int handle_dollar(o_string *dest, struct p_context *ctx, struct in_str *input)
2300 {
2301         int i, advance=0;
2302         char sep[]=" ";
2303         int ch = input->peek(input);  /* first character after the $ */
2304         debug_printf("handle_dollar: ch=%c\n",ch);
2305         if (isalpha(ch)) {
2306                 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2307                 ctx->child->sp++;
2308                 while(ch=b_peek(input),isalnum(ch) || ch=='_') {
2309                         b_getch(input);
2310                         b_addchr(dest,ch);
2311                 }
2312                 b_addchr(dest, SPECIAL_VAR_SYMBOL);
2313         } else if (isdigit(ch)) {
2314                 i = ch-'0';  /* XXX is $0 special? */
2315                 if (i<global_argc) {
2316                         parse_string(dest, ctx, global_argv[i]); /* recursion */
2317                 }
2318                 advance = 1;
2319         } else switch (ch) {
2320                 case '$':
2321                         b_adduint(dest,getpid());
2322                         advance = 1;
2323                         break;
2324                 case '!':
2325                         if (last_bg_pid > 0) b_adduint(dest, last_bg_pid);
2326                         advance = 1;
2327                         break;
2328                 case '?':
2329                         b_adduint(dest,last_return_code);
2330                         advance = 1;
2331                         break;
2332                 case '#':
2333                         b_adduint(dest,global_argc ? global_argc-1 : 0);
2334                         advance = 1;
2335                         break;
2336                 case '{':
2337                         b_addchr(dest, SPECIAL_VAR_SYMBOL);
2338                         ctx->child->sp++;
2339                         b_getch(input);
2340                         /* XXX maybe someone will try to escape the '}' */
2341                         while(ch=b_getch(input),ch!=EOF && ch!='}') {
2342                                 b_addchr(dest,ch);
2343                         }
2344                         if (ch != '}') {
2345                                 syntax();
2346                                 return 1;
2347                         }
2348                         b_addchr(dest, SPECIAL_VAR_SYMBOL);
2349                         break;
2350                 case '(':
2351                         b_getch(input);
2352                         process_command_subs(dest, ctx, input, ')');
2353                         break;
2354                 case '*':
2355                         sep[0]=ifs[0];
2356                         for (i=1; i<global_argc; i++) {
2357                                 parse_string(dest, ctx, global_argv[i]);
2358                                 if (i+1 < global_argc) parse_string(dest, ctx, sep);
2359                         }
2360                         break;
2361                 case '@':
2362                 case '-':
2363                 case '_':
2364                         /* still unhandled, but should be eventually */
2365                         bb_error_msg("unhandled syntax: $%c",ch);
2366                         return 1;
2367                         break;
2368                 default:
2369                         b_addqchr(dest,'$',dest->quote);
2370         }
2371         /* Eat the character if the flag was set.  If the compiler
2372          * is smart enough, we could substitute "b_getch(input);"
2373          * for all the "advance = 1;" above, and also end up with
2374          * a nice size-optimized program.  Hah!  That'll be the day.
2375          */
2376         if (advance) b_getch(input);
2377         return 0;
2378 }
2379
2380 int parse_string(o_string *dest, struct p_context *ctx, const char *src)
2381 {
2382         struct in_str foo;
2383         setup_string_in_str(&foo, src);
2384         return parse_stream(dest, ctx, &foo, '\0');
2385 }
2386
2387 /* return code is 0 for normal exit, 1 for syntax error */
2388 int parse_stream(o_string *dest, struct p_context *ctx,
2389         struct in_str *input, int end_trigger)
2390 {
2391         int ch, m;
2392         int redir_fd;
2393         redir_type redir_style;
2394         int next;
2395
2396         /* Only double-quote state is handled in the state variable dest->quote.
2397          * A single-quote triggers a bypass of the main loop until its mate is
2398          * found.  When recursing, quote state is passed in via dest->quote. */
2399
2400         debug_printf("parse_stream, end_trigger=%d\n",end_trigger);
2401         while ((ch=b_getch(input))!=EOF) {
2402                 m = map[ch];
2403                 next = (ch == '\n') ? 0 : b_peek(input);
2404                 debug_printf("parse_stream: ch=%c (%d) m=%d quote=%d\n",
2405                         ch,ch,m,dest->quote);
2406                 if (m==0 || ((m==1 || m==2) && dest->quote)) {
2407                         b_addqchr(dest, ch, dest->quote);
2408                 } else {
2409                         if (m==2) {  /* unquoted IFS */
2410                                 if (done_word(dest, ctx)) {
2411                                         return 1;
2412                                 }
2413                                 /* If we aren't performing a substitution, treat a newline as a
2414                                  * command separator.  */
2415                                 if (end_trigger != '\0' && ch=='\n')
2416                                         done_pipe(ctx,PIPE_SEQ);
2417                         }
2418                         if (ch == end_trigger && !dest->quote && ctx->w==RES_NONE) {
2419                                 debug_printf("leaving parse_stream (triggered)\n");
2420                                 return 0;
2421                         }
2422                         if (m!=2) switch (ch) {
2423                 case '#':
2424                         if (dest->length == 0 && !dest->quote) {
2425                                 while(ch=b_peek(input),ch!=EOF && ch!='\n') { b_getch(input); }
2426                         } else {
2427                                 b_addqchr(dest, ch, dest->quote);
2428                         }
2429                         break;
2430                 case '\\':
2431                         if (next == EOF) {
2432                                 syntax();
2433                                 return 1;
2434                         }
2435                         b_addqchr(dest, '\\', dest->quote);
2436                         b_addqchr(dest, b_getch(input), dest->quote);
2437                         break;
2438                 case '$':
2439                         if (handle_dollar(dest, ctx, input)!=0) return 1;
2440                         break;
2441                 case '\'':
2442                         dest->nonnull = 1;
2443                         while(ch=b_getch(input),ch!=EOF && ch!='\'') {
2444                                 b_addchr(dest,ch);
2445                         }
2446                         if (ch==EOF) {
2447                                 syntax();
2448                                 return 1;
2449                         }
2450                         break;
2451                 case '"':
2452                         dest->nonnull = 1;
2453                         dest->quote = !dest->quote;
2454                         break;
2455                 case '`':
2456                         process_command_subs(dest, ctx, input, '`');
2457                         break;
2458                 case '>':
2459                         redir_fd = redirect_opt_num(dest);
2460                         done_word(dest, ctx);
2461                         redir_style=REDIRECT_OVERWRITE;
2462                         if (next == '>') {
2463                                 redir_style=REDIRECT_APPEND;
2464                                 b_getch(input);
2465                         } else if (next == '(') {
2466                                 syntax();   /* until we support >(list) Process Substitution */
2467                                 return 1;
2468                         }
2469                         setup_redirect(ctx, redir_fd, redir_style, input);
2470                         break;
2471                 case '<':
2472                         redir_fd = redirect_opt_num(dest);
2473                         done_word(dest, ctx);
2474                         redir_style=REDIRECT_INPUT;
2475                         if (next == '<') {
2476                                 redir_style=REDIRECT_HEREIS;
2477                                 b_getch(input);
2478                         } else if (next == '>') {
2479                                 redir_style=REDIRECT_IO;
2480                                 b_getch(input);
2481                         } else if (next == '(') {
2482                                 syntax();   /* until we support <(list) Process Substitution */
2483                                 return 1;
2484                         }
2485                         setup_redirect(ctx, redir_fd, redir_style, input);
2486                         break;
2487                 case ';':
2488                         done_word(dest, ctx);
2489                         done_pipe(ctx,PIPE_SEQ);
2490                         break;
2491                 case '&':
2492                         done_word(dest, ctx);
2493                         if (next=='&') {
2494                                 b_getch(input);
2495                                 done_pipe(ctx,PIPE_AND);
2496                         } else {
2497                                 done_pipe(ctx,PIPE_BG);
2498                         }
2499                         break;
2500                 case '|':
2501                         done_word(dest, ctx);
2502                         if (next=='|') {
2503                                 b_getch(input);
2504                                 done_pipe(ctx,PIPE_OR);
2505                         } else {
2506                                 /* we could pick up a file descriptor choice here
2507                                  * with redirect_opt_num(), but bash doesn't do it.
2508                                  * "echo foo 2| cat" yields "foo 2". */
2509                                 done_command(ctx);
2510                         }
2511                         break;
2512                 case '(':
2513                 case '{':
2514                         if (parse_group(dest, ctx, input, ch)!=0) return 1;
2515                         break;
2516                 case ')':
2517                 case '}':
2518                         syntax();   /* Proper use of this character caught by end_trigger */
2519                         return 1;
2520                         break;
2521                 default:
2522                         syntax();   /* this is really an internal logic error */
2523                         return 1;
2524                         }
2525                 }
2526         }
2527         /* complain if quote?  No, maybe we just finished a command substitution
2528          * that was quoted.  Example:
2529          * $ echo "`cat foo` plus more"
2530          * and we just got the EOF generated by the subshell that ran "cat foo"
2531          * The only real complaint is if we got an EOF when end_trigger != '\0',
2532          * that is, we were really supposed to get end_trigger, and never got
2533          * one before the EOF.  Can't use the standard "syntax error" return code,
2534          * so that parse_stream_outer can distinguish the EOF and exit smoothly. */
2535         debug_printf("leaving parse_stream (EOF)\n");
2536         if (end_trigger != '\0') return -1;
2537         return 0;
2538 }
2539
2540 static void mapset(const char *set, int code)
2541 {
2542         const unsigned char *s;
2543         for (s = (const unsigned char *)set; *s; s++) map[(int)*s] = code;
2544 }
2545
2546 static void update_ifs_map(void)
2547 {
2548         /* char *ifs and char map[256] are both globals. */
2549         ifs = getenv("IFS");
2550         if (ifs == NULL) ifs=" \t\n";
2551         /* Precompute a list of 'flow through' behavior so it can be treated
2552          * quickly up front.  Computation is necessary because of IFS.
2553          * Special case handling of IFS == " \t\n" is not implemented.
2554          * The map[] array only really needs two bits each, and on most machines
2555          * that would be faster because of the reduced L1 cache footprint.
2556          */
2557         memset(map,0,sizeof(map)); /* most characters flow through always */
2558         mapset("\\$'\"`", 3);      /* never flow through */
2559         mapset("<>;&|(){}#", 1);   /* flow through if quoted */
2560         mapset(ifs, 2);            /* also flow through if quoted */
2561 }
2562
2563 /* most recursion does not come through here, the exception is
2564  * from builtin_source() */
2565 int parse_stream_outer(struct in_str *inp, int flag)
2566 {
2567
2568         struct p_context ctx;
2569         o_string temp=NULL_O_STRING;
2570         int rcode;
2571         do {
2572                 ctx.type = flag;
2573                 initialize_context(&ctx);
2574                 update_ifs_map();
2575                 if (!(flag & FLAG_PARSE_SEMICOLON) || (flag & FLAG_REPARSING)) mapset(";$&|", 0);
2576                 inp->promptmode=1;
2577                 rcode = parse_stream(&temp, &ctx, inp, '\n');
2578                 if (rcode != 1 && ctx.old_flag != 0) {
2579                         syntax();
2580                 }
2581                 if (rcode != 1 && ctx.old_flag == 0) {
2582                         done_word(&temp, &ctx);
2583                         done_pipe(&ctx,PIPE_SEQ);
2584                         run_list(ctx.list_head);
2585                 } else {
2586                         if (ctx.old_flag != 0) {
2587                                 free(ctx.stack);
2588                                 b_reset(&temp);
2589                         }
2590                         temp.nonnull = 0;
2591                         temp.quote = 0;
2592                         inp->p = NULL;
2593                         free_pipe_list(ctx.list_head,0);
2594                 }
2595                 b_free(&temp);
2596         } while (rcode != -1 && !(flag & FLAG_EXIT_FROM_LOOP));   /* loop on syntax errors, return on EOF */
2597         return 0;
2598 }
2599
2600 static int parse_string_outer(const char *s, int flag)
2601 {
2602         struct in_str input;
2603         setup_string_in_str(&input, s);
2604         return parse_stream_outer(&input, flag);
2605 }
2606
2607 static int parse_file_outer(FILE *f)
2608 {
2609         int rcode;
2610         struct in_str input;
2611         setup_file_in_str(&input, f);
2612         rcode = parse_stream_outer(&input, FLAG_PARSE_SEMICOLON);
2613         return rcode;
2614 }
2615
2616 /* Make sure we have a controlling tty.  If we get started under a job
2617  * aware app (like bash for example), make sure we are now in charge so
2618  * we don't fight over who gets the foreground */
2619 static void setup_job_control(void)
2620 {
2621         static pid_t shell_pgrp;
2622         /* Loop until we are in the foreground.  */
2623         while (tcgetpgrp (shell_terminal) != (shell_pgrp = getpgrp ()))
2624                 kill (- shell_pgrp, SIGTTIN);
2625
2626         /* Ignore interactive and job-control signals.  */
2627         signal(SIGINT, SIG_IGN);
2628         signal(SIGQUIT, SIG_IGN);
2629         signal(SIGTERM, SIG_IGN);
2630         signal(SIGTSTP, SIG_IGN);
2631         signal(SIGTTIN, SIG_IGN);
2632         signal(SIGTTOU, SIG_IGN);
2633         signal(SIGCHLD, SIG_IGN);
2634
2635         /* Put ourselves in our own process group.  */
2636         setsid();
2637         shell_pgrp = getpid ();
2638         setpgid (shell_pgrp, shell_pgrp);
2639
2640         /* Grab control of the terminal.  */
2641         tcsetpgrp(shell_terminal, shell_pgrp);
2642 }
2643
2644 int hush_main(int argc, char **argv)
2645 {
2646         int opt;
2647         FILE *input;
2648         char **e = environ;
2649
2650         /* XXX what should these be while sourcing /etc/profile? */
2651         global_argc = argc;
2652         global_argv = argv;
2653
2654         /* (re?) initialize globals.  Sometimes hush_main() ends up calling
2655          * hush_main(), therefore we cannot rely on the BSS to zero out this
2656          * stuff.  Reset these to 0 every time. */
2657         ifs = NULL;
2658         /* map[] is taken care of with call to update_ifs_map() */
2659         fake_mode = 0;
2660         interactive = 0;
2661         close_me_head = NULL;
2662         last_bg_pid = 0;
2663         job_list = NULL;
2664         last_jobid = 0;
2665
2666         /* Initialize some more globals to non-zero values */
2667         set_cwd();
2668     if (ENABLE_FEATURE_COMMAND_EDITING) cmdedit_set_initial_prompt();
2669         else PS1 = NULL;
2670         PS2 = "> ";
2671
2672         /* initialize our shell local variables with the values
2673          * currently living in the environment */
2674         if (e) {
2675                 for (; *e; e++)
2676                         set_local_var(*e, 2);   /* without call putenv() */
2677         }
2678
2679         last_return_code=EXIT_SUCCESS;
2680
2681
2682         if (argv[0] && argv[0][0] == '-') {
2683                 debug_printf("\nsourcing /etc/profile\n");
2684                 if ((input = fopen("/etc/profile", "r")) != NULL) {
2685                         mark_open(fileno(input));
2686                         parse_file_outer(input);
2687                         mark_closed(fileno(input));
2688                         fclose(input);
2689                 }
2690         }
2691         input=stdin;
2692
2693         while ((opt = getopt(argc, argv, "c:xif")) > 0) {
2694                 switch (opt) {
2695                         case 'c':
2696                                 {
2697                                         global_argv = argv+optind;
2698                                         global_argc = argc-optind;
2699                                         opt = parse_string_outer(optarg, FLAG_PARSE_SEMICOLON);
2700                                         goto final_return;
2701                                 }
2702                                 break;
2703                         case 'i':
2704                                 interactive++;
2705                                 break;
2706                         case 'f':
2707                                 fake_mode++;
2708                                 break;
2709                         default:
2710 #ifndef BB_VER
2711                                 fprintf(stderr, "Usage: sh [FILE]...\n"
2712                                                 "   or: sh -c command [args]...\n\n");
2713                                 exit(EXIT_FAILURE);
2714 #else
2715                                 bb_show_usage();
2716 #endif
2717                 }
2718         }
2719         /* A shell is interactive if the `-i' flag was given, or if all of
2720          * the following conditions are met:
2721          *        no -c command
2722          *    no arguments remaining or the -s flag given
2723          *    standard input is a terminal
2724          *    standard output is a terminal
2725          *    Refer to Posix.2, the description of the `sh' utility. */
2726         if (argv[optind]==NULL && input==stdin &&
2727                         isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
2728                 interactive++;
2729         }
2730
2731         debug_printf("\ninteractive=%d\n", interactive);
2732         if (interactive) {
2733                 /* Looks like they want an interactive shell */
2734 #ifndef CONFIG_FEATURE_SH_EXTRA_QUIET
2735                 printf( "\n\n%s hush - the humble shell v0.01 (testing)\n",
2736                         BB_BANNER);
2737                 printf( "Enter 'help' for a list of built-in commands.\n\n");
2738 #endif
2739                 setup_job_control();
2740         }
2741
2742         if (argv[optind]==NULL) {
2743                 opt=parse_file_outer(stdin);
2744                 goto final_return;
2745         }
2746
2747         debug_printf("\nrunning script '%s'\n", argv[optind]);
2748         global_argv = argv+optind;
2749         global_argc = argc-optind;
2750         input = xfopen(argv[optind], "r");
2751         opt = parse_file_outer(input);
2752
2753 #ifdef CONFIG_FEATURE_CLEAN_UP
2754         fclose(input);
2755         if (cwd && cwd != bb_msg_unknown)
2756                 free((char*)cwd);
2757         {
2758                 struct variables *cur, *tmp;
2759                 for(cur = top_vars; cur; cur = tmp) {
2760                         tmp = cur->next;
2761                         if (!cur->flg_read_only) {
2762                                 free(cur->name);
2763                                 free(cur->value);
2764                                 free(cur);
2765                         }
2766                 }
2767         }
2768 #endif
2769
2770 final_return:
2771         return opt ? opt : last_return_code;
2772 }
2773
2774 static char *insert_var_value(char *inp)
2775 {
2776         int res_str_len = 0;
2777         int len;
2778         int done = 0;
2779         char *p, *p1, *res_str = NULL;
2780
2781         while ((p = strchr(inp, SPECIAL_VAR_SYMBOL))) {
2782                 if (p != inp) {
2783                         len = p - inp;
2784                         res_str = xrealloc(res_str, (res_str_len + len));
2785                         strncpy((res_str + res_str_len), inp, len);
2786                         res_str_len += len;
2787                 }
2788                 inp = ++p;
2789                 p = strchr(inp, SPECIAL_VAR_SYMBOL);
2790                 *p = '\0';
2791                 if ((p1 = lookup_param(inp))) {
2792                         len = res_str_len + strlen(p1);
2793                         res_str = xrealloc(res_str, (1 + len));
2794                         strcpy((res_str + res_str_len), p1);
2795                         res_str_len = len;
2796                 }
2797                 *p = SPECIAL_VAR_SYMBOL;
2798                 inp = ++p;
2799                 done = 1;
2800         }
2801         if (done) {
2802                 res_str = xrealloc(res_str, (1 + res_str_len + strlen(inp)));
2803                 strcpy((res_str + res_str_len), inp);
2804                 while ((p = strchr(res_str, '\n'))) {
2805                         *p = ' ';
2806                 }
2807         }
2808         return (res_str == NULL) ? inp : res_str;
2809 }
2810
2811 static char **make_list_in(char **inp, char *name)
2812 {
2813         int len, i;
2814         int name_len = strlen(name);
2815         int n = 0;
2816         char **list;
2817         char *p1, *p2, *p3;
2818
2819         /* create list of variable values */
2820         list = xmalloc(sizeof(*list));
2821         for (i = 0; inp[i]; i++) {
2822                 p3 = insert_var_value(inp[i]);
2823                 p1 = p3;
2824                 while (*p1) {
2825                         if ((*p1 == ' ')) {
2826                                 p1++;
2827                                 continue;
2828                         }
2829                         if ((p2 = strchr(p1, ' '))) {
2830                                 len = p2 - p1;
2831                         } else {
2832                                 len = strlen(p1);
2833                                 p2 = p1 + len;
2834                         }
2835                         /* we use n + 2 in realloc for list,because we add
2836                          * new element and then we will add NULL element */
2837                         list = xrealloc(list, sizeof(*list) * (n + 2));
2838                         list[n] = xmalloc(2 + name_len + len);
2839                         strcpy(list[n], name);
2840                         strcat(list[n], "=");
2841                         strncat(list[n], p1, len);
2842                         list[n++][name_len + len + 1] = '\0';
2843                         p1 = p2;
2844                 }
2845                 if (p3 != inp[i]) free(p3);
2846         }
2847         list[n] = NULL;
2848         return list;
2849 }
2850
2851 /* Make new string for parser */
2852 static char * make_string(char ** inp)
2853 {
2854         char *p;
2855         char *str = NULL;
2856         int n;
2857         int len = 2;
2858
2859         for (n = 0; inp[n]; n++) {
2860                 p = insert_var_value(inp[n]);
2861                 str = xrealloc(str, (len + strlen(p)));
2862                 if (n) {
2863                         strcat(str, " ");
2864                 } else {
2865                         *str = '\0';
2866                 }
2867                 strcat(str, p);
2868                 len = strlen(str) + 3;
2869                 if (p != inp[n]) free(p);
2870         }
2871         len = strlen(str);
2872         *(str + len) = '\n';
2873         *(str + len + 1) = '\0';
2874         return str;
2875 }