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