lash.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * lash -- the BusyBox Lame-Ass SHell
   4  *
   5  * Copyright (C) 1999,2000,2001 by Lineo, inc.
   6  * Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
   7  *
   8  * Based in part on ladsh.c by Michael K. Johnson and Erik W. Troan, which is
   9  * under the following liberal license: "We have placed this source code in the
  10  * public domain. Use it in any project, free or commercial."
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  25  *
  26  */
  27
  28 /* The parsing engine of this program is officially at a dead-end.
  29  * Future work in that direction should move to the work posted
  30  * at http://doolittle.faludi.com/~larry/parser.html .
  31  * A start on the integration of that work with the rest of sh.c
  32  * is at http://codepoet.org/sh.c .
  33  */
  34 //
  35 //This works pretty well now, and is now on by default.
  36 #define BB_FEATURE_SH_ENVIRONMENT
  37 //
  38 //Backtick support has some problems, use at your own risk!
  39 //#define BB_FEATURE_SH_BACKTICKS
  40 //
  41 //If, then, else, etc. support..  This should now behave basically
  42 //like any other Bourne shell -- sortof...
  43 #define BB_FEATURE_SH_IF_EXPRESSIONS
  44 //
  45 /* This is currently sortof broken, only for the brave... */
  46 #undef HANDLE_CONTINUATION_CHARS
  47 //
  48 /* This would be great -- if wordexp wouldn't strip all quoting
  49  * out from the target strings...  As is, a parser needs  */
  50 #undef BB_FEATURE_SH_WORDEXP
  51 //
  52 //For debugging/development on the shell only...
  53 //#define DEBUG_SHELL
  54
  55
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <ctype.h>
  59 #include <errno.h>
  60 #include <fcntl.h>
  61 #include <signal.h>
  62 #include <string.h>
  63 #include <sys/ioctl.h>
  64 #include <sys/wait.h>
  65 #include <unistd.h>
  66 #include <getopt.h>
  67
  68 //#define BB_FEATURE_SH_WORDEXP
  69
  70 #ifdef BB_FEATURE_SH_WORDEXP
  71 #include <wordexp.h>
  72 #define expand_t        wordexp_t
  73 #undef BB_FEATURE_SH_BACKTICKS
  74 #else
  75 #include <glob.h>
  76 #define expand_t        glob_t
  77 #endif
  78 #include "busybox.h"
  79 #include "cmdedit.h"
  80
  81
  82 static const int MAX_LINE = 256;        /* size of input buffer for cwd data */
  83 static const int MAX_READ = 128;        /* size of input buffer for `read' builtin */
  84 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n"
  85
  86
  87 enum redir_type { REDIRECT_INPUT, REDIRECT_OVERWRITE,
  88         REDIRECT_APPEND
  89 };
  90
  91 static const unsigned int DEFAULT_CONTEXT=0x1;
  92 static const unsigned int IF_TRUE_CONTEXT=0x2;
  93 static const unsigned int IF_FALSE_CONTEXT=0x4;
  94 static const unsigned int THEN_EXP_CONTEXT=0x8;
  95 static const unsigned int ELSE_EXP_CONTEXT=0x10;
  96
  97
  98 struct jobset {
  99         struct job *head;                       /* head of list of running jobs */
 100         struct job *fg;                         /* current foreground job */
 101 };
 102
 103 struct redir_struct {
 104         enum redir_type type;   /* type of redirection */
 105         int fd;                                         /* file descriptor being redirected */
 106         char *filename;                         /* file to redirect fd to */
 107 };
 108
 109 struct child_prog {
 110         pid_t pid;                                      /* 0 if exited */
 111         char **argv;                            /* program name and arguments */
 112         int num_redirects;                      /* elements in redirection array */
 113         struct redir_struct *redirects; /* I/O redirects */
 114         int is_stopped;                         /* is the program currently running? */
 115         struct job *family;                     /* pointer back to the child's parent job */
 116 };
 117
 118 struct job {
 119         int jobid;                                      /* job number */
 120         int num_progs;                          /* total number of programs in job */
 121         int running_progs;                      /* number of programs running */
 122         char *text;                                     /* name of job */
 123         char *cmdbuf;                           /* buffer various argv's point into */
 124         pid_t pgrp;                                     /* process group ID for the job */
 125         struct child_prog *progs;       /* array of programs in job */
 126         struct job *next;                       /* to track background commands */
 127         int stopped_progs;                      /* number of programs alive, but stopped */
 128         unsigned int job_context;       /* bitmask defining current context */
 129         struct jobset *job_list;
 130 };
 131
 132 struct built_in_command {
 133         char *cmd;                                      /* name */
 134         char *descr;                            /* description */
 135         int (*function) (struct child_prog *);  /* function ptr */
 136 };
 137
 138 struct close_me {
 139         int fd;
 140         struct close_me *next;
 141 };
 142
 143 /* function prototypes for builtins */
 144 static int builtin_cd(struct child_prog *cmd);
 145 static int builtin_env(struct child_prog *dummy);
 146 static int builtin_exec(struct child_prog *cmd);
 147 static int builtin_exit(struct child_prog *cmd);
 148 static int builtin_fg_bg(struct child_prog *cmd);
 149 static int builtin_help(struct child_prog *cmd);
 150 static int builtin_jobs(struct child_prog *dummy);
 151 static int builtin_pwd(struct child_prog *dummy);
 152 static int builtin_export(struct child_prog *cmd);
 153 static int builtin_source(struct child_prog *cmd);
 154 static int builtin_unset(struct child_prog *cmd);
 155 static int builtin_read(struct child_prog *cmd);
 156 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 157 static int builtin_if(struct child_prog *cmd);
 158 static int builtin_then(struct child_prog *cmd);
 159 static int builtin_else(struct child_prog *cmd);
 160 static int builtin_fi(struct child_prog *cmd);
 161 /* function prototypes for shell stuff */
 162 static int run_command_predicate(char *cmd);
 163 #endif
 164
 165
 166 /* function prototypes for shell stuff */
 167 static void mark_open(int fd);
 168 static void mark_closed(int fd);
 169 static void close_all(void);
 170 static void checkjobs(struct jobset *job_list);
 171 static int get_command(FILE * source, char *command);
 172 static int parse_command(char **command_ptr, struct job *job, int *inbg);
 173 static int run_command(struct job *newjob, int inbg, int outpipe[2]);
 174 static int pseudo_exec(struct child_prog *cmd) __attribute__ ((noreturn));
 175 static int busy_loop(FILE * input);
 176
 177
 178 /* Table of built-in functions (these are non-forking builtins, meaning they
 179  * can change global variables in the parent shell process but they will not
 180  * work with pipes and redirects; 'unset foo | whatever' will not work) */
 181 static struct built_in_command bltins[] = {
 182         {"bg", "Resume a job in the background", builtin_fg_bg},
 183         {"cd", "Change working directory", builtin_cd},
 184         {"exec", "Exec command, replacing this shell with the exec'd process", builtin_exec},
 185         {"exit", "Exit from shell()", builtin_exit},
 186         {"fg", "Bring job into the foreground", builtin_fg_bg},
 187         {"jobs", "Lists the active jobs", builtin_jobs},
 188         {"export", "Set environment variable", builtin_export},
 189         {"unset", "Unset environment variable", builtin_unset},
 190         {"read", "Input environment variable", builtin_read},
 191         {".", "Source-in and run commands in a file", builtin_source},
 192         /* to do: add ulimit */
 193 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 194         {"if", NULL, builtin_if},
 195         {"then", NULL, builtin_then},
 196         {"else", NULL, builtin_else},
 197         {"fi", NULL, builtin_fi},
 198 #endif
 199         {NULL, NULL, NULL}
 200 };
 201
 202 /* Table of forking built-in functions (things that fork cannot change global
 203  * variables in the parent process, such as the current working directory) */
 204 static struct built_in_command bltins_forking[] = {
 205         {"env", "Print all environment variables", builtin_env},
 206         {"pwd", "Print current directory", builtin_pwd},
 207         {"help", "List shell built-in commands", builtin_help},
 208         {NULL, NULL, NULL}
 209 };
 210
 211
 212 /* Variables we export */
 213 unsigned int shell_context;  /* Used in cmdedit.c to reset the
 214                                                                 context when someone hits ^C */
 215
 216
 217 /* Globals that are static to this file */
 218 static char *cwd;
 219 static char *local_pending_command = NULL;
 220 static struct jobset job_list = { NULL, NULL };
 221 static int argc;
 222 static char **argv;
 223 static struct close_me *close_me_head;
 224 #ifdef BB_FEATURE_SH_ENVIRONMENT
 225 static int last_bg_pid;
 226 static int last_return_code;
 227 static int show_x_trace;
 228 #endif
 229 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 230 static char syntax_err[]="syntax error near unexpected token";
 231 #endif
 232
 233 static char *PS1;
 234 static char *PS2;
 235
 236
 237 #ifdef DEBUG_SHELL
 238 static inline void debug_printf(const char *format, ...)
 239 {
 240         va_list args;
 241         va_start(args, format);
 242         vfprintf(stderr, format, args);
 243         va_end(args);
 244 }
 245 #else
 246 static inline void debug_printf(const char *format, ...) { }
 247 #endif
 248
 249 /*
 250         Most builtins need access to the struct child_prog that has
 251         their arguments, previously coded as cmd->progs[0].  That coding
 252         can exhibit a bug, if the builtin is not the first command in
 253         a pipeline: "echo foo | exec sort" will attempt to exec foo.
 254
 255 builtin   previous use      notes
 256 ------ -----------------  ---------
 257 cd      cmd->progs[0]
 258 env     0
 259 exec    cmd->progs[0]  squashed bug: didn't look for applets or forking builtins
 260 exit    cmd->progs[0]
 261 fg_bg   cmd->progs[0], job_list->head, job_list->fg
 262 help    0
 263 jobs    job_list->head
 264 pwd     0
 265 export  cmd->progs[0]  passes cmd, job_list to builtin_env(), which ignores them
 266 source  cmd->progs[0]
 267 unset   cmd->progs[0]
 268 read    cmd->progs[0]
 269 if      cmd->job_context,  cmd->text
 270 then    cmd->job_context,  cmd->text
 271 else    cmd->job_context,  cmd->text
 272 fi      cmd->job_context
 273
 274 The use of cmd->text by if/then/else/fi is hopelessly hacky.
 275 Would it work to increment cmd->progs[0]->argv and recurse,
 276 somewhat like builtin_exec does?
 277
 278 I added "struct job *family;" to struct child_prog,
 279 and switched API to builtin_foo(struct child_prog *child);
 280 So   cmd->text        becomes  child->family->text
 281      cmd->job_context  becomes  child->family->job_context
 282      cmd->progs[0]    becomes  *child
 283      job_list          becomes  child->family->job_list
 284  */
 285
 286 /* built-in 'cd <path>' handler */
 287 static int builtin_cd(struct child_prog *child)
 288 {
 289         char *newdir;
 290
 291         if (child->argv[1] == NULL)
 292                 newdir = getenv("HOME");
 293         else
 294                 newdir = child->argv[1];
 295         if (chdir(newdir)) {
 296                 printf("cd: %s: %m\n", newdir);
 297                 return EXIT_FAILURE;
 298         }
 299         getcwd(cwd, sizeof(char)*MAX_LINE);
 300
 301         return EXIT_SUCCESS;
 302 }
 303
 304 /* built-in 'env' handler */
 305 static int builtin_env(struct child_prog *dummy)
 306 {
 307         char **e;
 308
 309         for (e = environ; *e; e++) {
 310                 printf( "%s\n", *e);
 311         }
 312         return (0);
 313 }
 314
 315 /* built-in 'exec' handler */
 316 static int builtin_exec(struct child_prog *child)
 317 {
 318         if (child->argv[1] == NULL)
 319                 return EXIT_SUCCESS;   /* Really? */
 320         child->argv++;
 321         close_all();
 322         pseudo_exec(child);
 323         /* never returns */
 324 }
 325
 326 /* built-in 'exit' handler */
 327 static int builtin_exit(struct child_prog *child)
 328 {
 329         if (child->argv[1] == NULL)
 330                 exit(EXIT_SUCCESS);
 331
 332         exit (atoi(child->argv[1]));
 333 }
 334
 335 /* built-in 'fg' and 'bg' handler */
 336 static int builtin_fg_bg(struct child_prog *child)
 337 {
 338         int i, jobNum;
 339         struct job *job=NULL;
 340
 341         if (!child->argv[1] || child->argv[2]) {
 342                 error_msg("%s: exactly one argument is expected",
 343                                 child->argv[0]);
 344                 return EXIT_FAILURE;
 345         }
 346
 347         if (sscanf(child->argv[1], "%%%d", &jobNum) != 1) {
 348                 error_msg("%s: bad argument '%s'",
 349                                 child->argv[0], child->argv[1]);
 350                 return EXIT_FAILURE;
 351         }
 352
 353         for (job = child->family->job_list->head; job; job = job->next) {
 354                 if (job->jobid == jobNum) {
 355                         break;
 356                 }
 357         }
 358
 359         if (!job) {
 360                 error_msg("%s: unknown job %d",
 361                                 child->argv[0], jobNum);
 362                 return EXIT_FAILURE;
 363         }
 364
 365         if (*child->argv[0] == 'f') {
 366                 /* Make this job the foreground job */
 367                 /* suppress messages when run from /linuxrc mag@sysgo.de */
 368                 if (tcsetpgrp(0, job->pgrp) && errno != ENOTTY)
 369                         perror_msg("tcsetpgrp");
 370                 child->family->job_list->fg = job;
 371         }
 372
 373         /* Restart the processes in the job */
 374         for (i = 0; i < job->num_progs; i++)
 375                 job->progs[i].is_stopped = 0;
 376
 377         kill(-job->pgrp, SIGCONT);
 378
 379         job->stopped_progs = 0;
 380
 381         return EXIT_SUCCESS;
 382 }
 383
 384 /* built-in 'help' handler */
 385 static int builtin_help(struct child_prog *dummy)
 386 {
 387         struct built_in_command *x;
 388
 389         printf("\nBuilt-in commands:\n");
 390         printf("-------------------\n");
 391         for (x = bltins; x->cmd; x++) {
 392                 if (x->descr==NULL)
 393                         continue;
 394                 printf("%s\t%s\n", x->cmd, x->descr);
 395         }
 396         for (x = bltins_forking; x->cmd; x++) {
 397                 if (x->descr==NULL)
 398                         continue;
 399                 printf("%s\t%s\n", x->cmd, x->descr);
 400         }
 401         printf("\n\n");
 402         return EXIT_SUCCESS;
 403 }
 404
 405 /* built-in 'jobs' handler */
 406 static int builtin_jobs(struct child_prog *child)
 407 {
 408         struct job *job;
 409         char *status_string;
 410
 411         for (job = child->family->job_list->head; job; job = job->next) {
 412                 if (job->running_progs == job->stopped_progs)
 413                         status_string = "Stopped";
 414                 else
 415                         status_string = "Running";
 416
 417                 printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->text);
 418         }
 419         return EXIT_SUCCESS;
 420 }
 421
 422
 423 /* built-in 'pwd' handler */
 424 static int builtin_pwd(struct child_prog *dummy)
 425 {
 426         getcwd(cwd, MAX_LINE);
 427         printf( "%s\n", cwd);
 428         return EXIT_SUCCESS;
 429 }
 430
 431 /* built-in 'export VAR=value' handler */
 432 static int builtin_export(struct child_prog *child)
 433 {
 434         int res;
 435         char *v = child->argv[1];
 436
 437         if (v == NULL) {
 438                 return (builtin_env(child));
 439         }
 440         res = putenv(v);
 441         if (res)
 442                 fprintf(stderr, "export: %m\n");
 443 #ifndef BB_FEATURE_SH_SIMPLE_PROMPT
 444         if (strncmp(v, "PS1=", 4)==0)
 445                 PS1 = getenv("PS1");
 446         else if (strncmp(v, "PS2=", 4)==0)
 447                 PS2 = getenv("PS2");
 448 #endif
 449         return (res);
 450 }
 451
 452 /* built-in 'read VAR' handler */
 453 static int builtin_read(struct child_prog *child)
 454 {
 455         int res = 0, len, newlen;
 456         char *s;
 457         char string[MAX_READ];
 458
 459         if (child->argv[1]) {
 460                 /* argument (VAR) given: put "VAR=" into buffer */
 461                 strcpy(string, child->argv[1]);
 462                 len = strlen(string);
 463                 string[len++] = '=';
 464                 string[len]   = '\0';
 465                 fgets(&string[len], sizeof(string) - len, stdin);       /* read string */
 466                 newlen = strlen(string);
 467                 if(newlen > len)
 468                         string[--newlen] = '\0';        /* chomp trailing newline */
 469                 /*
 470                 ** string should now contain "VAR=<value>"
 471                 ** copy it (putenv() won't do that, so we must make sure
 472                 ** the string resides in a static buffer!)
 473                 */
 474                 res = -1;
 475                 if((s = strdup(string)))
 476                         res = putenv(s);
 477                 if (res)
 478                         fprintf(stderr, "read: %m\n");
 479         }
 480         else
 481                 fgets(string, sizeof(string), stdin);
 482
 483         return (res);
 484 }
 485
 486 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 487 /* Built-in handler for 'if' commands */
 488 static int builtin_if(struct child_prog *child)
 489 {
 490         struct job *cmd = child->family;
 491         int status;
 492         char* charptr1=cmd->text+3; /* skip over the leading 'if ' */
 493
 494         /* Now run the 'if' command */
 495         debug_printf( "job=%p entering builtin_if ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
 496         status = run_command_predicate(charptr1);
 497         debug_printf( "if test returned ");
 498         if (status == 0) {
 499                 debug_printf( "TRUE\n");
 500                 cmd->job_context |= IF_TRUE_CONTEXT;
 501         } else {
 502                 debug_printf( "FALSE\n");
 503                 cmd->job_context |= IF_FALSE_CONTEXT;
 504         }
 505         debug_printf("job=%p builtin_if set job context to %x\n", cmd, cmd->job_context);
 506         shell_context++;
 507
 508         return status;
 509 }
 510
 511 /* Built-in handler for 'then' (part of the 'if' command) */
 512 static int builtin_then(struct child_prog *child)
 513 {
 514         struct job *cmd = child->family;
 515         char* charptr1=cmd->text+5; /* skip over the leading 'then ' */
 516
 517         debug_printf( "job=%p entering builtin_then ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
 518         if (! (cmd->job_context & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
 519                 shell_context = 0; /* Reset the shell's context on an error */
 520                 error_msg("%s `then'", syntax_err);
 521                 return EXIT_FAILURE;
 522         }
 523
 524         cmd->job_context |= THEN_EXP_CONTEXT;
 525         debug_printf("job=%p builtin_then set job context to %x\n", cmd, cmd->job_context);
 526
 527         /* If the if result was FALSE, skip the 'then' stuff */
 528         if (cmd->job_context & IF_FALSE_CONTEXT) {
 529                 return EXIT_SUCCESS;
 530         }
 531
 532         /* Seems the if result was TRUE, so run the 'then' command */
 533         debug_printf( "'then' now running '%s'\n", charptr1);
 534
 535         return(run_command_predicate(charptr1));
 536 }
 537
 538 /* Built-in handler for 'else' (part of the 'if' command) */
 539 static int builtin_else(struct child_prog *child)
 540 {
 541         struct job *cmd = child->family;
 542         char* charptr1=cmd->text+5; /* skip over the leading 'else ' */
 543
 544         debug_printf( "job=%p entering builtin_else ('%s')-- context=%d\n", cmd, charptr1, cmd->job_context);
 545
 546         if (! (cmd->job_context & THEN_EXP_CONTEXT)) {
 547                 shell_context = 0; /* Reset the shell's context on an error */
 548                 error_msg("%s `else'", syntax_err);
 549                 return EXIT_FAILURE;
 550         }
 551         /* If the if result was TRUE, skip the 'else' stuff */
 552         if (cmd->job_context & IF_TRUE_CONTEXT) {
 553                 return EXIT_SUCCESS;
 554         }
 555
 556         cmd->job_context |= ELSE_EXP_CONTEXT;
 557         debug_printf("job=%p builtin_else set job context to %x\n", cmd, cmd->job_context);
 558
 559         /* Now run the 'else' command */
 560         debug_printf( "'else' now running '%s'\n", charptr1);
 561         return(run_command_predicate(charptr1));
 562 }
 563
 564 /* Built-in handler for 'fi' (part of the 'if' command) */
 565 static int builtin_fi(struct child_prog *child)
 566 {
 567         struct job *cmd = child->family;
 568         debug_printf( "job=%p entering builtin_fi ('%s')-- context=%d\n", cmd, "", cmd->job_context);
 569         if (! (cmd->job_context & (IF_TRUE_CONTEXT|IF_FALSE_CONTEXT))) {
 570                 shell_context = 0; /* Reset the shell's context on an error */
 571                 error_msg("%s `fi'", syntax_err);
 572                 return EXIT_FAILURE;
 573         }
 574         /* Clear out the if and then context bits */
 575         cmd->job_context &= ~(IF_TRUE_CONTEXT|IF_FALSE_CONTEXT|THEN_EXP_CONTEXT|ELSE_EXP_CONTEXT);
 576         debug_printf("job=%p builtin_fi set job context to %x\n", cmd, cmd->job_context);
 577         shell_context--;
 578         return EXIT_SUCCESS;
 579 }
 580 #endif
 581
 582 /* Built-in '.' handler (read-in and execute commands from file) */
 583 static int builtin_source(struct child_prog *child)
 584 {
 585         FILE *input;
 586         int status;
 587         int fd;
 588
 589         if (child->argv[1] == NULL)
 590                 return EXIT_FAILURE;
 591
 592         input = fopen(child->argv[1], "r");
 593         if (!input) {
 594                 printf( "Couldn't open file '%s'\n", child->argv[1]);
 595                 return EXIT_FAILURE;
 596         }
 597
 598         fd=fileno(input);
 599         mark_open(fd);
 600         /* Now run the file */
 601         status = busy_loop(input);
 602         fclose(input);
 603         mark_closed(fd);
 604         return (status);
 605 }
 606
 607 /* built-in 'unset VAR' handler */
 608 static int builtin_unset(struct child_prog *child)
 609 {
 610         if (child->argv[1] == NULL) {
 611                 printf( "unset: parameter required.\n");
 612                 return EXIT_FAILURE;
 613         }
 614         unsetenv(child->argv[1]);
 615         return EXIT_SUCCESS;
 616 }
 617
 618 #ifdef BB_FEATURE_SH_IF_EXPRESSIONS
 619 /* currently used by if/then/else.
 620  *
 621  * Reparsing the command line for this purpose is gross,
 622  * incorrect, and fundamentally unfixable; in particular,
 623  * think about what happens with command substitution.
 624  * We really need to pull out the run, wait, return status
 625  * functionality out of busy_loop so we can child->argv++
 626  * and use that, without going back through parse_command.
 627  */
 628 static int run_command_predicate(char *cmd)
 629 {
 630         int n=strlen(cmd);
 631         local_pending_command = xmalloc(n+1);
 632         strncpy(local_pending_command, cmd, n);
 633         local_pending_command[n]='\0';
 634         return( busy_loop(NULL));
 635 }
 636 #endif
 637
 638 static void mark_open(int fd)
 639 {
 640         struct close_me *new = xmalloc(sizeof(struct close_me));
 641         new->fd = fd;
 642         new->next = close_me_head;
 643         close_me_head = new;
 644 }
 645
 646 static void mark_closed(int fd)
 647 {
 648         struct close_me *tmp;
 649         if (close_me_head == NULL || close_me_head->fd != fd)
 650                 error_msg_and_die("corrupt close_me");
 651         tmp = close_me_head;
 652         close_me_head = close_me_head->next;
 653         free(tmp);
 654 }
 655
 656 static void close_all()
 657 {
 658         struct close_me *c, *tmp;
 659         for (c=close_me_head; c; c=tmp) {
 660                 close(c->fd);
 661                 tmp=c->next;
 662                 free(c);
 663         }
 664         close_me_head = NULL;
 665 }
 666
 667
 668 /* free up all memory from a job */
 669 static void free_job(struct job *cmd)
 670 {
 671         int i;
 672         struct jobset *keep;
 673
 674         for (i = 0; i < cmd->num_progs; i++) {
 675                 free(cmd->progs[i].argv);
 676                 if (cmd->progs[i].redirects)
 677                         free(cmd->progs[i].redirects);
 678         }
 679         if (cmd->progs)
 680                 free(cmd->progs);
 681         if (cmd->text)
 682                 free(cmd->text);
 683         if (cmd->cmdbuf)
 684                 free(cmd->cmdbuf);
 685         keep = cmd->job_list;
 686         memset(cmd, 0, sizeof(struct job));
 687         cmd->job_list = keep;
 688 }
 689
 690 /* remove a job from a jobset */
 691 static void remove_job(struct jobset *j_list, struct job *job)
 692 {
 693         struct job *prevjob;
 694
 695         free_job(job);
 696         if (job == j_list->head) {
 697                 j_list->head = job->next;
 698         } else {
 699                 prevjob = j_list->head;
 700                 while (prevjob->next != job)
 701                         prevjob = prevjob->next;
 702                 prevjob->next = job->next;
 703         }
 704
 705         free(job);
 706 }
 707
 708 /* Checks to see if any background processes have exited -- if they
 709    have, figure out why and see if a job has completed */
 710 static void checkjobs(struct jobset *j_list)
 711 {
 712         struct job *job;
 713         pid_t childpid;
 714         int status;
 715         int prognum = 0;
 716
 717         while ((childpid = waitpid(-1, &status, WNOHANG | WUNTRACED)) > 0) {
 718                 for (job = j_list->head; job; job = job->next) {
 719                         prognum = 0;
 720                         while (prognum < job->num_progs &&
 721                                    job->progs[prognum].pid != childpid) prognum++;
 722                         if (prognum < job->num_progs)
 723                                 break;
 724                 }
 725
 726                 /* This happens on backticked commands */
 727                 if(job==NULL)
 728                         return;
 729
 730                 if (WIFEXITED(status) || WIFSIGNALED(status)) {
 731                         /* child exited */
 732                         job->running_progs--;
 733                         job->progs[prognum].pid = 0;
 734
 735                         if (!job->running_progs) {
 736                                 printf(JOB_STATUS_FORMAT, job->jobid, "Done", job->text);
 737                                 remove_job(j_list, job);
 738                         }
 739                 } else {
 740                         /* child stopped */
 741                         job->stopped_progs++;
 742                         job->progs[prognum].is_stopped = 1;
 743
 744                         if (job->stopped_progs == job->num_progs) {
 745                                 printf(JOB_STATUS_FORMAT, job->jobid, "Stopped",
 746                                            job->text);
 747                         }
 748                 }
 749         }
 750
 751         if (childpid == -1 && errno != ECHILD)
 752                 perror_msg("waitpid");
 753 }
 754
 755 /* squirrel != NULL means we squirrel away copies of stdin, stdout,
 756  * and stderr if they are redirected. */
 757 static int setup_redirects(struct child_prog *prog, int squirrel[])
 758 {
 759         int i;
 760         int openfd;
 761         int mode = O_RDONLY;
 762         struct redir_struct *redir = prog->redirects;
 763
 764         for (i = 0; i < prog->num_redirects; i++, redir++) {
 765                 switch (redir->type) {
 766                 case REDIRECT_INPUT:
 767                         mode = O_RDONLY;
 768                         break;
 769                 case REDIRECT_OVERWRITE:
 770                         mode = O_WRONLY | O_CREAT | O_TRUNC;
 771                         break;
 772                 case REDIRECT_APPEND:
 773                         mode = O_WRONLY | O_CREAT | O_APPEND;
 774                         break;
 775                 }
 776
 777                 openfd = open(redir->filename, mode, 0666);
 778                 if (openfd < 0) {
 779                         /* this could get lost if stderr has been redirected, but
 780                            bash and ash both lose it as well (though zsh doesn't!) */
 781                         perror_msg("error opening %s", redir->filename);
 782                         return 1;
 783                 }
 784
 785                 if (openfd != redir->fd) {
 786                         if (squirrel && redir->fd < 3) {
 787                                 squirrel[redir->fd] = dup(redir->fd);
 788                         }
 789                         dup2(openfd, redir->fd);
 790                         close(openfd);
 791                 }
 792         }
 793
 794         return 0;
 795 }
 796
 797 static void restore_redirects(int squirrel[])
 798 {
 799         int i, fd;
 800         for (i=0; i<3; i++) {
 801                 fd = squirrel[i];
 802                 if (fd != -1) {
 803                         /* No error checking.  I sure wouldn't know what
 804                          * to do with an error if I found one! */
 805                         dup2(fd, i);
 806                         close(fd);
 807                 }
 808         }
 809 }
 810
 811 static inline void cmdedit_set_initial_prompt(void)
 812 {
 813 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
 814         PS1 = NULL;
 815         PS2 = "> ";
 816 #else
 817         PS1 = getenv("PS1");
 818         if(PS1==0) {
 819                 PS1 = "\\w \\$ ";
 820         }
 821         PS2 = getenv("PS2");
 822         if(PS2==0)
 823                 PS2 = "> ";
 824 #endif
 825 }
 826
 827 static inline void setup_prompt_string(char **prompt_str)
 828 {
 829 #ifdef BB_FEATURE_SH_SIMPLE_PROMPT
 830         /* Set up the prompt */
 831         if (shell_context == 0) {
 832                 if (PS1)
 833                         free(PS1);
 834                 PS1=xmalloc(strlen(cwd)+4);
 835                 sprintf(PS1, "%s %s", cwd, ( geteuid() != 0 ) ?  "$ ":"# ");
 836                 *prompt_str = PS1;
 837         } else {
 838                 *prompt_str = PS2;
 839         }
 840 #else
 841         *prompt_str = (shell_context==0)? PS1 : PS2;
 842 #endif
 843 }
 844
 845 static int get_command(FILE * source, char *command)
 846 {
 847         char *prompt_str;
 848
 849         if (source == NULL) {
 850                 if (local_pending_command) {
 851                         /* a command specified (-c option): return it & mark it done */
 852                         strcpy(command, local_pending_command);
 853                         free(local_pending_command);
 854                         local_pending_command = NULL;
 855                         return 0;
 856                 }
 857                 return 1;
 858         }
 859
 860         if (source == stdin) {
 861                 setup_prompt_string(&prompt_str);
 862
 863 #ifdef BB_FEATURE_COMMAND_EDITING
 864                 /*
 865                 ** enable command line editing only while a command line
 866                 ** is actually being read; otherwise, we'll end up bequeathing
 867                 ** atexit() handlers and other unwanted stuff to our
 868                 ** child processes (rob@sysgo.de)
 869                 */
 870                 cmdedit_read_input(prompt_str, command);
 871                 cmdedit_terminate();
 872                 return 0;
 873 #else
 874                 fputs(prompt_str, stdout);
 875 #endif
 876         }
 877
 878         if (!fgets(command, BUFSIZ - 2, source)) {
 879                 if (source == stdin)
 880                         printf("\n");
 881                 return 1;
 882         }
 883
 884         return 0;
 885 }
 886
 887 #ifdef BB_FEATURE_SH_ENVIRONMENT
 888 static char* itoa(register int i)
 889 {
 890         static char a[7]; /* Max 7 ints */
 891         register char *b = a + sizeof(a) - 1;
 892         int   sign = (i < 0);
 893
 894         if (sign)
 895                 i = -i;
 896         *b = 0;
 897         do
 898         {
 899                 *--b = '0' + (i % 10);
 900                 i /= 10;
 901         }
 902         while (i);
 903         if (sign)
 904                 *--b = '-';
 905         return b;
 906 }
 907 #endif
 908
 909 #if defined BB_FEATURE_SH_ENVIRONMENT && ! defined BB_FEATURE_SH_WORDEXP
 910 char * strsep_space( char *string, int * ix)
 911 {
 912         char *token, *begin;
 913
 914         begin = string;
 915
 916         /* Short circuit the trivial case */
 917         if ( !string || ! string[*ix])
 918                 return NULL;
 919
 920         /* Find the end of the token. */
 921         while( string && string[*ix] && !isspace(string[*ix]) ) {
 922                 (*ix)++;
 923         }
 924
 925         /* Find the end of any whitespace trailing behind
 926          * the token and let that be part of the token */
 927         while( string && string[*ix] && isspace(string[*ix]) ) {
 928                 (*ix)++;
 929         }
 930
 931         if (! string && *ix==0) {
 932                 /* Nothing useful was found */
 933                 return NULL;
 934         }
 935
 936         token = xmalloc(*ix+1);
 937         token[*ix] = '\0';
 938         strncpy(token, string,  *ix);
 939
 940         return token;
 941 }
 942 #endif
 943
 944
 945 static int expand_arguments(char *command)
 946 {
 947 #ifdef BB_FEATURE_SH_ENVIRONMENT
 948         expand_t expand_result;
 949         char *src, *dst, *var;
 950         int ix = 0;
 951         int i=0, length, total_length=0, retval;
 952         const char *out_of_space = "out of space during expansion";
 953 #endif
 954
 955         /* get rid of the terminating \n */
 956         chomp(command);
 957
 958         /* Fix up escape sequences to be the Real Thing(tm) */
 959         while( command && command[ix]) {
 960                 if (command[ix] == '\\') {
 961                         char *tmp = command+ix+1;
 962                         command[ix] = process_escape_sequence(  &tmp );
 963                         memmove(command+ix + 1, tmp, strlen(tmp)+1);
 964                 }
 965                 ix++;
 966         }
 967
 968 #ifdef BB_FEATURE_SH_ENVIRONMENT
 969
 970
 971 #ifdef BB_FEATURE_SH_WORDEXP
 972         /* This first part uses wordexp() which is a wonderful C lib
 973          * function which expands nearly everything.  */
 974         retval = wordexp (command, &expand_result, WRDE_SHOWERR);
 975         if (retval == WRDE_NOSPACE) {
 976                 /* Mem may have been allocated... */
 977                 wordfree (&expand_result);
 978                 error_msg(out_of_space);
 979                 return FALSE;
 980         }
 981         if (retval < 0) {
 982                 /* Some other error.  */
 983                 error_msg("syntax error");
 984                 return FALSE;
 985         }
 986
 987         if (expand_result.we_wordc > 0) {
 988                 /* Convert from char** (one word per string) to a simple char*,
 989                  * but don't overflow command which is BUFSIZ in length */
 990                 *command = '\0';
 991                 while (i < expand_result.we_wordc && total_length < BUFSIZ) {
 992                         length=strlen(expand_result.we_wordv[i])+1;
 993                         if (BUFSIZ-total_length-length <= 0) {
 994                                 error_msg(out_of_space);
 995                                 return FALSE;
 996                         }
 997                         strcat(command+total_length, expand_result.we_wordv[i++]);
 998                         strcat(command+total_length, " ");
 999                         total_length+=length;
1000                 }
1001                 wordfree (&expand_result);
1002         }
1003 #else
1004
1005         /* Ok.  They don't have a recent glibc and they don't have uClibc.  Chances
1006          * are about 100% they don't have wordexp(). So instead the best we can do
1007          * is use glob and then fixup environment variables and such ourselves.
1008          * This is better then nothing, but certainly not perfect */
1009
1010         /* It turns out that glob is very stupid.  We have to feed it one word at a
1011          * time since it can't cope with a full string.  Here we convert command
1012          * (char*) into cmd (char**, one word per string) */
1013         {
1014
1015                 int flags = GLOB_NOCHECK
1016 #ifdef GLOB_BRACE
1017                                 | GLOB_BRACE
1018 #endif
1019 #ifdef GLOB_TILDE
1020                                 | GLOB_TILDE
1021 #endif
1022                         ;
1023                 char *tmpcmd, *cmd, *cmd_copy;
1024                 /* We need a clean copy, so strsep can mess up the copy while
1025                  * we write stuff into the original (in a minute) */
1026                 cmd = cmd_copy = strdup(command);
1027                 *command = '\0';
1028                 for (ix = 0, tmpcmd = cmd;
1029                                 (tmpcmd = strsep_space(cmd, &ix)) != NULL; cmd += ix, ix=0) {
1030                         if (*tmpcmd == '\0')
1031                                 break;
1032                         retval = glob(tmpcmd, flags, NULL, &expand_result);
1033                         free(tmpcmd); /* Free mem allocated by strsep_space */
1034                         if (retval == GLOB_NOSPACE) {
1035                                 /* Mem may have been allocated... */
1036                                 globfree (&expand_result);
1037                                 error_msg(out_of_space);
1038                                 return FALSE;
1039                         } else if (retval != 0) {
1040                                 /* Some other error.  GLOB_NOMATCH shouldn't
1041                                  * happen because of the GLOB_NOCHECK flag in
1042                                  * the glob call. */
1043                                 error_msg("syntax error");
1044                                 return FALSE;
1045                         } else {
1046                         /* Convert from char** (one word per string) to a simple char*,
1047                          * but don't overflow command which is BUFSIZ in length */
1048                                 for (i=0; i < expand_result.gl_pathc; i++) {
1049                                         length=strlen(expand_result.gl_pathv[i]);
1050                                         if (total_length+length+1 >= BUFSIZ) {
1051                                                 error_msg(out_of_space);
1052                                                 return FALSE;
1053                                         }
1054                                         if (i>0) {
1055                                                 strcat(command+total_length, " ");
1056                                                 total_length+=1;
1057                                         }
1058                                         strcat(command+total_length, expand_result.gl_pathv[i]);
1059                                         total_length+=length;
1060                                 }
1061                                 globfree (&expand_result);
1062                         }
1063                 }
1064                 free(cmd_copy);
1065                 trim(command);
1066         }
1067
1068 #endif
1069
1070         /* Now do the shell variable substitutions which
1071          * wordexp can't do for us, namely $? and $! */
1072         src = command;
1073         while((dst = strchr(src,'$')) != NULL){
1074                 var = NULL;
1075                 switch(*(dst+1)) {
1076                         case '?':
1077                                 var = itoa(last_return_code);
1078                                 break;
1079                         case '!':
1080                                 if (last_bg_pid==-1)
1081                                         *(var)='\0';
1082                                 else
1083                                         var = itoa(last_bg_pid);
1084                                 break;
1085                                 /* Everything else like $$, $#, $[0-9], etc should all be
1086                                  * expanded by wordexp(), so we can in theory skip that stuff
1087                                  * here, but just to be on the safe side (i.e. since uClibc
1088                                  * wordexp doesn't do this stuff yet), lets leave it in for
1089                                  * now. */
1090                         case '$':
1091                                 var = itoa(getpid());
1092                                 break;
1093                         case '#':
1094                                 var = itoa(argc-1);
1095                                 break;
1096                         case '0':case '1':case '2':case '3':case '4':
1097                         case '5':case '6':case '7':case '8':case '9':
1098                                 {
1099                                         int ixx=*(dst + 1)-48;
1100                                         if (ixx >= argc) {
1101                                                 var='\0';
1102                                         } else {
1103                                                 var = argv[ixx];
1104                                         }
1105                                 }
1106                                 break;
1107
1108                 }
1109                 if (var) {
1110                         /* a single character construction was found, and
1111                          * already handled in the case statement */
1112                         src=dst+2;
1113                 } else {
1114                         /* Looks like an environment variable */
1115                         char delim_hold;
1116                         int num_skip_chars=0;
1117                         int dstlen = strlen(dst);
1118                         /* Is this a ${foo} type variable? */
1119                         if (dstlen >=2 && *(dst+1) == '{') {
1120                                 src=strchr(dst+1, '}');
1121                                 num_skip_chars=1;
1122                         } else {
1123                                 src=dst+1;
1124                                 while(isalnum(*src) || *src=='_') src++;
1125                         }
1126                         if (src == NULL) {
1127                                 src = dst+dstlen;
1128                         }
1129                         delim_hold=*src;
1130                         *src='\0';  /* temporary */
1131                         var = getenv(dst + 1 + num_skip_chars);
1132                         *src=delim_hold;
1133                         src += num_skip_chars;
1134                 }
1135                 if (var == NULL) {
1136                         /* Seems we got an un-expandable variable.  So delete it. */
1137                         var = "";
1138                 }
1139                 {
1140                         int subst_len = strlen(var);
1141                         int trail_len = strlen(src);
1142                         if (dst+subst_len+trail_len >= command+BUFSIZ) {
1143                                 error_msg(out_of_space);
1144                                 return FALSE;
1145                         }
1146                         /* Move stuff to the end of the string to accommodate
1147                          * filling the created gap with the new stuff */
1148                         memmove(dst+subst_len, src, trail_len+1);
1149                         /* Now copy in the new stuff */
1150                         memcpy(dst, var, subst_len);
1151                         src = dst+subst_len;
1152                 }
1153         }
1154
1155 #endif
1156         return TRUE;
1157 }
1158
1159 /* Return cmd->num_progs as 0 if no command is present (e.g. an empty
1160    line). If a valid command is found, command_ptr is set to point to
1161    the beginning of the next command (if the original command had more
1162    then one job associated with it) or NULL if no more commands are
1163    present. */
1164 static int parse_command(char **command_ptr, struct job *job, int *inbg)
1165 {
1166         char *command;
1167         char *return_command = NULL;
1168         char *src, *buf, *chptr;
1169         int argc_l = 0;
1170         int done = 0;
1171         int argv_alloced;
1172         int i;
1173         char quote = '\0';
1174         int count;
1175         struct child_prog *prog;
1176
1177         /* skip leading white space */
1178         while (**command_ptr && isspace(**command_ptr))
1179                 (*command_ptr)++;
1180
1181         /* this handles empty lines or leading '#' characters */
1182         if (!**command_ptr || (**command_ptr == '#')) {
1183                 job->num_progs=0;
1184                 return 0;
1185         }
1186
1187         *inbg = 0;
1188         job->num_progs = 1;
1189         job->progs = xmalloc(sizeof(*job->progs));
1190
1191         /* We set the argv elements to point inside of this string. The
1192            memory is freed by free_job(). Allocate twice the original
1193            length in case we need to quote every single character.
1194
1195            Getting clean memory relieves us of the task of NULL
1196            terminating things and makes the rest of this look a bit
1197            cleaner (though it is, admittedly, a tad less efficient) */
1198         job->cmdbuf = command = xcalloc(2*strlen(*command_ptr) + 1, sizeof(char));
1199         job->text = NULL;
1200
1201         prog = job->progs;
1202         prog->num_redirects = 0;
1203         prog->redirects = NULL;
1204         prog->is_stopped = 0;
1205         prog->family = job;
1206
1207         argv_alloced = 5;
1208         prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1209         prog->argv[0] = job->cmdbuf;
1210
1211         buf = command;
1212         src = *command_ptr;
1213         while (*src && !done) {
1214                 if (quote == *src) {
1215                         quote = '\0';
1216                 } else if (quote) {
1217                         if (*src == '\\') {
1218                                 src++;
1219                                 if (!*src) {
1220                                         error_msg("character expected after \\");
1221                                         free_job(job);
1222                                         return 1;
1223                                 }
1224
1225                                 /* in shell, "\'" should yield \' */
1226                                 if (*src != quote) {
1227                                         *buf++ = '\\';
1228                                         *buf++ = '\\';
1229                                 }
1230                         } else if (*src == '*' || *src == '?' || *src == '[' ||
1231                                            *src == ']') *buf++ = '\\';
1232                         *buf++ = *src;
1233                 } else if (isspace(*src)) {
1234                         if (*prog->argv[argc_l]) {
1235                                 buf++, argc_l++;
1236                                 /* +1 here leaves room for the NULL which ends argv */
1237                                 if ((argc_l + 1) == argv_alloced) {
1238                                         argv_alloced += 5;
1239                                         prog->argv = xrealloc(prog->argv,
1240                                                                                   sizeof(*prog->argv) *
1241                                                                                   argv_alloced);
1242                                 }
1243                                 prog->argv[argc_l] = buf;
1244                         }
1245                 } else
1246                         switch (*src) {
1247                         case '"':
1248                         case '\'':
1249                                 quote = *src;
1250                                 break;
1251
1252                         case '#':                       /* comment */
1253                                 if (*(src-1)== '$')
1254                                         *buf++ = *src;
1255                                 else
1256                                         done = 1;
1257                                 break;
1258
1259                         case '>':                       /* redirects */
1260                         case '<':
1261                                 i = prog->num_redirects++;
1262                                 prog->redirects = xrealloc(prog->redirects,
1263                                                                                           sizeof(*prog->redirects) *
1264                                                                                           (i + 1));
1265
1266                                 prog->redirects[i].fd = -1;
1267                                 if (buf != prog->argv[argc_l]) {
1268                                         /* the stuff before this character may be the file number
1269                                            being redirected */
1270                                         prog->redirects[i].fd =
1271                                                 strtol(prog->argv[argc_l], &chptr, 10);
1272
1273                                         if (*chptr && *prog->argv[argc_l]) {
1274                                                 buf++, argc_l++;
1275                                                 prog->argv[argc_l] = buf;
1276                                         }
1277                                 }
1278
1279                                 if (prog->redirects[i].fd == -1) {
1280                                         if (*src == '>')
1281                                                 prog->redirects[i].fd = 1;
1282                                         else
1283                                                 prog->redirects[i].fd = 0;
1284                                 }
1285
1286                                 if (*src++ == '>') {
1287                                         if (*src == '>')
1288                                                 prog->redirects[i].type =
1289                                                         REDIRECT_APPEND, src++;
1290                                         else
1291                                                 prog->redirects[i].type = REDIRECT_OVERWRITE;
1292                                 } else {
1293                                         prog->redirects[i].type = REDIRECT_INPUT;
1294                                 }
1295
1296                                 /* This isn't POSIX sh compliant. Oh well. */
1297                                 chptr = src;
1298                                 while (isspace(*chptr))
1299                                         chptr++;
1300
1301                                 if (!*chptr) {
1302                                         error_msg("file name expected after %c", *(src-1));
1303                                         free_job(job);
1304                                         job->num_progs=0;
1305                                         return 1;
1306                                 }
1307
1308                                 prog->redirects[i].filename = buf;
1309                                 while (*chptr && !isspace(*chptr))
1310                                         *buf++ = *chptr++;
1311
1312                                 src = chptr - 1;        /* we src++ later */
1313                                 prog->argv[argc_l] = ++buf;
1314                                 break;
1315
1316                         case '|':                       /* pipe */
1317                                 /* finish this command */
1318                                 if (*prog->argv[argc_l])
1319                                         argc_l++;
1320                                 if (!argc_l) {
1321                                         error_msg("empty command in pipe");
1322                                         free_job(job);
1323                                         job->num_progs=0;
1324                                         return 1;
1325                                 }
1326                                 prog->argv[argc_l] = NULL;
1327
1328                                 /* and start the next */
1329                                 job->num_progs++;
1330                                 job->progs = xrealloc(job->progs,
1331                                                                           sizeof(*job->progs) * job->num_progs);
1332                                 prog = job->progs + (job->num_progs - 1);
1333                                 prog->num_redirects = 0;
1334                                 prog->redirects = NULL;
1335                                 prog->is_stopped = 0;
1336                                 prog->family = job;
1337                                 argc_l = 0;
1338
1339                                 argv_alloced = 5;
1340                                 prog->argv = xmalloc(sizeof(*prog->argv) * argv_alloced);
1341                                 prog->argv[0] = ++buf;
1342
1343                                 src++;
1344                                 while (*src && isspace(*src))
1345                                         src++;
1346
1347                                 if (!*src) {
1348                                         error_msg("empty command in pipe");
1349                                         free_job(job);
1350                                         job->num_progs=0;
1351                                         return 1;
1352                                 }
1353                                 src--;                  /* we'll ++ it at the end of the loop */
1354
1355                                 break;
1356
1357                         case '&':                       /* background */
1358                                 *inbg = 1;
1359                         case ';':                       /* multiple commands */
1360                                 done = 1;
1361                                 return_command = *command_ptr + (src - *command_ptr) + 1;
1362                                 break;
1363
1364 #ifdef BB_FEATURE_SH_BACKTICKS
1365                         case '`':
1366                                 /* Exec a backtick-ed command */
1367                                 /* Besides any previous brokenness, I have not
1368                                  * updated backtick handling for close_me support.
1369                                  * I don't know if it needs it or not.  -- LRD */
1370                                 {
1371                                         char* charptr1=NULL, *charptr2;
1372                                         char* ptr=NULL;
1373                                         struct job *newjob;
1374                                         struct jobset njob_list = { NULL, NULL };
1375                                         int pipefd[2];
1376                                         int size;
1377
1378                                         ptr=strchr(++src, '`');
1379                                         if (ptr==NULL) {
1380                                                 fprintf(stderr, "Unmatched '`' in command\n");
1381                                                 free_job(job);
1382                                                 return 1;
1383                                         }
1384
1385                                         /* Make some space to hold just the backticked command */
1386                                         charptr1 = charptr2 = xmalloc(1+ptr-src);
1387                                         memcpy(charptr1, src, ptr-src);
1388                                         charptr1[ptr-src] = '\0';
1389                                         newjob = xmalloc(sizeof(struct job));
1390                                         newjob->job_list = &njob_list;
1391                                         /* Now parse and run the backticked command */
1392                                         if (!parse_command(&charptr1, newjob, inbg)
1393                                                         && newjob->num_progs) {
1394                                                 pipe(pipefd);
1395                                                 run_command(newjob, 0, pipefd);
1396                                         }
1397                                         checkjobs(job->job_list);
1398                                         free_job(newjob);  /* doesn't actually free newjob,
1399                                                              looks like a memory leak */
1400                                         free(charptr2);
1401
1402                                         /* Make a copy of any stuff left over in the command
1403                                          * line after the second backtick */
1404                                         charptr2 = xmalloc(strlen(ptr)+1);
1405                                         memcpy(charptr2, ptr+1, strlen(ptr));
1406
1407
1408                                         /* Copy the output from the backtick-ed command into the
1409                                          * command line, making extra room as needed  */
1410                                         --src;
1411                                         charptr1 = xmalloc(BUFSIZ);
1412                                         while ( (size=full_read(pipefd[0], charptr1, BUFSIZ-1)) >0) {
1413                                                 int newsize=src - *command_ptr + size + 1 + strlen(charptr2);
1414                                                 if (newsize > BUFSIZ) {
1415                                                         *command_ptr=xrealloc(*command_ptr, newsize);
1416                                                 }
1417                                                 memcpy(src, charptr1, size);
1418                                                 src+=size;
1419                                         }
1420                                         free(charptr1);
1421                                         close(pipefd[0]);
1422                                         if (*(src-1)=='\n')
1423                                                 --src;
1424
1425                                         /* Now paste into the *command_ptr all the stuff
1426                                          * leftover after the second backtick */
1427                                         memcpy(src, charptr2, strlen(charptr2)+1);
1428                                         free(charptr2);
1429
1430                                         /* Now recursively call parse_command to deal with the new
1431                                          * and improved version of the command line with the backtick
1432                                          * results expanded in place... */
1433                                         {
1434                                                 struct jobset *jl=job->job_list;
1435                                                 free_job(job);
1436                                                 job->job_list = jl;
1437                                         }
1438                                         return(parse_command(command_ptr, job, inbg));
1439                                 }
1440                                 break;
1441 #endif // BB_FEATURE_SH_BACKTICKS
1442
1443                         case '\\':
1444                                 src++;
1445                                 if (!*src) {
1446 /* This is currently a little broken... */
1447 #ifdef HANDLE_CONTINUATION_CHARS
1448                                         /* They fed us a continuation char, so continue reading stuff
1449                                          * on the next line, then tack that onto the end of the current
1450                                          * command */
1451                                         char *command;
1452                                         int newsize;
1453                                         printf("erik: found a continue char at EOL...\n");
1454                                         command = (char *) xcalloc(BUFSIZ, sizeof(char));
1455                                         if (get_command(input, command)) {
1456                                                 error_msg("character expected after \\");
1457                                                 free(command);
1458                                                 free_job(job);
1459                                                 return 1;
1460                                         }
1461                                         newsize = strlen(*command_ptr) + strlen(command) + 2;
1462                                         if (newsize > BUFSIZ) {
1463                                                 printf("erik: doing realloc\n");
1464                                                 *command_ptr=xrealloc(*command_ptr, newsize);
1465                                         }
1466                                         printf("erik: A: *command_ptr='%s'\n", *command_ptr);
1467                                         memcpy(--src, command, strlen(command));
1468                                         printf("erik: B: *command_ptr='%s'\n", *command_ptr);
1469                                         free(command);
1470                                         break;
1471 #else
1472                                         error_msg("character expected after \\");
1473                                         free_job(job);
1474                                         return 1;
1475 #endif
1476                                 }
1477                                 if (*src == '*' || *src == '[' || *src == ']'
1478                                         || *src == '?') *buf++ = '\\';
1479                                 /* fallthrough */
1480                         default:
1481                                 *buf++ = *src;
1482                         }
1483
1484                 src++;
1485         }
1486
1487         if (*prog->argv[argc_l]) {
1488                 argc_l++;
1489         }
1490         if (!argc_l) {
1491                 free_job(job);
1492                 return 0;
1493         }
1494         prog->argv[argc_l] = NULL;
1495
1496         if (!return_command) {
1497                 job->text = xmalloc(strlen(*command_ptr) + 1);
1498                 strcpy(job->text, *command_ptr);
1499         } else {
1500                 /* This leaves any trailing spaces, which is a bit sloppy */
1501                 count = return_command - *command_ptr;
1502                 job->text = xmalloc(count + 1);
1503                 strncpy(job->text, *command_ptr, count);
1504                 job->text[count] = '\0';
1505         }
1506
1507         *command_ptr = return_command;
1508
1509         return 0;
1510 }
1511
1512 /* Run the child_prog, no matter what kind of command it uses.
1513  */
1514 static int pseudo_exec(struct child_prog *child)
1515 {
1516         struct built_in_command *x;
1517 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1518         char *name;
1519 #endif
1520
1521         /* Check if the command matches any of the non-forking builtins.
1522          * Depending on context, this might be redundant.  But it's
1523          * easier to waste a few CPU cycles than it is to figure out
1524          * if this is one of those cases.
1525          */
1526         for (x = bltins; x->cmd; x++) {
1527                 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1528                         exit(x->function(child));
1529                 }
1530         }
1531
1532         /* Check if the command matches any of the forking builtins. */
1533         for (x = bltins_forking; x->cmd; x++) {
1534                 if (strcmp(child->argv[0], x->cmd) == 0) {
1535                         applet_name=x->cmd;
1536                         exit (x->function(child));
1537                 }
1538         }
1539 #ifdef BB_FEATURE_SH_STANDALONE_SHELL
1540         /* Check if the command matches any busybox internal
1541          * commands ("applets") here.  Following discussions from
1542          * November 2000 on busybox@opensource.lineo.com, don't use
1543          * get_last_path_component().  This way explicit (with
1544          * slashes) filenames will never be interpreted as an
1545          * applet, just like with builtins.  This way the user can
1546          * override an applet with an explicit filename reference.
1547          * The only downside to this change is that an explicit
1548          * /bin/foo invocation will fork and exec /bin/foo, even if
1549          * /bin/foo is a symlink to busybox.
1550          */
1551         name = child->argv[0];
1552
1553 #ifdef BB_FEATURE_SH_APPLETS_ALWAYS_WIN
1554         /* If you enable BB_FEATURE_SH_APPLETS_ALWAYS_WIN, then
1555          * if you run /bin/cat, it will use BusyBox cat even if
1556          * /bin/cat exists on the filesystem and is _not_ busybox.
1557          * Some systems want this, others do not.  Choose wisely.  :-)
1558          */
1559         name = get_last_path_component(name);
1560 #endif
1561
1562         {
1563             char** argv_l=child->argv;
1564             int argc_l;
1565             for(argc_l=0;*argv_l!=NULL; argv_l++, argc_l++);
1566             optind = 1;
1567             run_applet_by_name(name, argc_l, child->argv);
1568         }
1569 #endif
1570
1571         execvp(child->argv[0], child->argv);
1572         perror_msg_and_die("%s", child->argv[0]);
1573 }
1574
1575 static void insert_job(struct job *newjob, int inbg)
1576 {
1577         struct job *thejob;
1578         struct jobset *j_list=newjob->job_list;
1579
1580         /* find the ID for thejob to use */
1581         newjob->jobid = 1;
1582         for (thejob = j_list->head; thejob; thejob = thejob->next)
1583                 if (thejob->jobid >= newjob->jobid)
1584                         newjob->jobid = thejob->jobid + 1;
1585
1586         /* add thejob to the list of running jobs */
1587         if (!j_list->head) {
1588                 thejob = j_list->head = xmalloc(sizeof(*thejob));
1589         } else {
1590                 for (thejob = j_list->head; thejob->next; thejob = thejob->next) /* nothing */;
1591                 thejob->next = xmalloc(sizeof(*thejob));
1592                 thejob = thejob->next;
1593         }
1594
1595         *thejob = *newjob;   /* physically copy the struct job */
1596         thejob->next = NULL;
1597         thejob->running_progs = thejob->num_progs;
1598         thejob->stopped_progs = 0;
1599
1600         if (inbg) {
1601                 /* we don't wait for background thejobs to return -- append it
1602                    to the list of backgrounded thejobs and leave it alone */
1603                 printf("[%d] %d\n", thejob->jobid,
1604                            newjob->progs[newjob->num_progs - 1].pid);
1605 #ifdef BB_FEATURE_SH_ENVIRONMENT
1606                 last_bg_pid=newjob->progs[newjob->num_progs - 1].pid;
1607 #endif
1608         } else {
1609                 newjob->job_list->fg = thejob;
1610
1611                 /* move the new process group into the foreground */
1612                 /* suppress messages when run from /linuxrc mag@sysgo.de */
1613                 if (tcsetpgrp(0, newjob->pgrp) && errno != ENOTTY)
1614                         perror_msg("tcsetpgrp");
1615         }
1616 }
1617
1618 static int run_command(struct job *newjob, int inbg, int outpipe[2])
1619 {
1620         /* struct job *thejob; */
1621         int i;
1622         int nextin, nextout;
1623         int pipefds[2];                         /* pipefd[0] is for reading */
1624         struct built_in_command *x;
1625         struct child_prog *child;
1626
1627         nextin = 0, nextout = 1;
1628         for (i = 0; i < newjob->num_progs; i++) {
1629                 child = & (newjob->progs[i]);
1630
1631                 if ((i + 1) < newjob->num_progs) {
1632                         if (pipe(pipefds)<0) perror_msg_and_die("pipe");
1633                         nextout = pipefds[1];
1634                 } else {
1635                         if (outpipe[1]!=-1) {
1636                                 nextout = outpipe[1];
1637                         } else {
1638                                 nextout = 1;
1639                         }
1640                 }
1641
1642 #ifdef BB_FEATURE_SH_ENVIRONMENT
1643                 if (show_x_trace==TRUE) {
1644                         int j;
1645                         fputc('+', stderr);
1646                         for (j = 0; child->argv[j]; j++) {
1647                                 fputc(' ', stderr);
1648                                 fputs(child->argv[j], stderr);
1649                         }
1650                         fputc('\n', stderr);
1651                 }
1652 #endif
1653
1654                 /* Check if the command matches any non-forking builtins,
1655                  * but only if this is a simple command.
1656                  * Non-forking builtins within pipes have to fork anyway,
1657                  * and are handled in pseudo_exec.  "echo foo | read bar"
1658                  * is doomed to failure, and doesn't work on bash, either.
1659                  */
1660                 if (newjob->num_progs == 1) {
1661                         for (x = bltins; x->cmd; x++) {
1662                                 if (strcmp(child->argv[0], x->cmd) == 0 ) {
1663                                         int squirrel[] = {-1, -1, -1};
1664                                         int rcode;
1665                                         setup_redirects(child, squirrel);
1666                                         rcode = x->function(child);
1667                                         restore_redirects(squirrel);
1668                                         return rcode;
1669                                 }
1670                         }
1671                 }
1672
1673                 if (!(child->pid = fork())) {
1674                         signal(SIGTTOU, SIG_DFL);
1675
1676                         close_all();
1677
1678                         if (outpipe[1]!=-1) {
1679                                 close(outpipe[0]);
1680                         }
1681                         if (nextin != 0) {
1682                                 dup2(nextin, 0);
1683                                 close(nextin);
1684                         }
1685
1686                         if (nextout != 1) {
1687                                 dup2(nextout, 1);
1688                                 dup2(nextout, 2);  /* Really? */
1689                                 close(nextout);
1690                                 close(pipefds[0]);
1691                         }
1692
1693                         /* explicit redirects override pipes */
1694                         setup_redirects(child,NULL);
1695
1696                         pseudo_exec(child);
1697                 }
1698                 if (outpipe[1]!=-1) {
1699                         close(outpipe[1]);
1700                 }
1701
1702                 /* put our child in the process group whose leader is the
1703                    first process in this pipe */
1704                 setpgid(child->pid, newjob->progs[0].pid);
1705                 if (nextin != 0)
1706                         close(nextin);
1707                 if (nextout != 1)
1708                         close(nextout);
1709
1710                 /* If there isn't another process, nextin is garbage
1711                    but it doesn't matter */
1712                 nextin = pipefds[0];
1713         }
1714
1715         newjob->pgrp = newjob->progs[0].pid;
1716
1717         insert_job(newjob, inbg);
1718
1719         return 0;
1720 }
1721
1722 static int busy_loop(FILE * input)
1723 {
1724         char *command;
1725         char *next_command = NULL;
1726         struct job newjob;
1727         pid_t  parent_pgrp;
1728         int i;
1729         int inbg;
1730         int status;
1731         newjob.job_list = &job_list;
1732         newjob.job_context = DEFAULT_CONTEXT;
1733
1734         /* save current owner of TTY so we can restore it on exit */
1735         parent_pgrp = tcgetpgrp(0);
1736
1737         command = (char *) xcalloc(BUFSIZ, sizeof(char));
1738
1739         /* don't pay any attention to this signal; it just confuses
1740            things and isn't really meant for shells anyway */
1741         signal(SIGTTOU, SIG_IGN);
1742
1743         while (1) {
1744                 if (!job_list.fg) {
1745                         /* no job is in the foreground */
1746
1747                         /* see if any background processes have exited */
1748                         checkjobs(&job_list);
1749
1750                         if (!next_command) {
1751                                 if (get_command(input, command))
1752                                         break;
1753                                 next_command = command;
1754                         }
1755
1756                         if (expand_arguments(next_command) == FALSE) {
1757                                 free(command);
1758                                 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1759                                 next_command = NULL;
1760                                 continue;
1761                         }
1762
1763                         if (!parse_command(&next_command, &newjob, &inbg) &&
1764                                 newjob.num_progs) {
1765                                 int pipefds[2] = {-1,-1};
1766                                 debug_printf( "job=%p fed to run_command by busy_loop()'\n",
1767                                                 &newjob);
1768                                 run_command(&newjob, inbg, pipefds);
1769                         }
1770                         else {
1771                                 free(command);
1772                                 command = (char *) xcalloc(BUFSIZ, sizeof(char));
1773                                 next_command = NULL;
1774                         }
1775                 } else {
1776                         /* a job is running in the foreground; wait for it */
1777                         i = 0;
1778                         while (!job_list.fg->progs[i].pid ||
1779                                    job_list.fg->progs[i].is_stopped == 1) i++;
1780
1781                         if (waitpid(job_list.fg->progs[i].pid, &status, WUNTRACED)<0)
1782                                 perror_msg_and_die("waitpid(%d)",job_list.fg->progs[i].pid);
1783
1784                         if (WIFEXITED(status) || WIFSIGNALED(status)) {
1785                                 /* the child exited */
1786                                 job_list.fg->running_progs--;
1787                                 job_list.fg->progs[i].pid = 0;
1788
1789 #ifdef BB_FEATURE_SH_ENVIRONMENT
1790                                 last_return_code=WEXITSTATUS(status);
1791                                 debug_printf("'%s' exited -- return code %d\n",
1792                                                 job_list.fg->text, last_return_code);
1793 #endif
1794                                 if (!job_list.fg->running_progs) {
1795                                         /* child exited */
1796                                         remove_job(&job_list, job_list.fg);
1797                                         job_list.fg = NULL;
1798                                 }
1799                         } else {
1800                                 /* the child was stopped */
1801                                 job_list.fg->stopped_progs++;
1802                                 job_list.fg->progs[i].is_stopped = 1;
1803
1804                                 if (job_list.fg->stopped_progs == job_list.fg->running_progs) {
1805                                         printf("\n" JOB_STATUS_FORMAT, job_list.fg->jobid,
1806                                                    "Stopped", job_list.fg->text);
1807                                         job_list.fg = NULL;
1808                                 }
1809                         }
1810
1811                         if (!job_list.fg) {
1812                                 /* move the shell to the foreground */
1813                                 /* suppress messages when run from /linuxrc mag@sysgo.de */
1814                                 if (tcsetpgrp(0, getpid()) && errno != ENOTTY)
1815                                         perror_msg("tcsetpgrp");
1816                         }
1817                 }
1818         }
1819         free(command);
1820
1821         /* return controlling TTY back to parent process group before exiting */
1822         if (tcsetpgrp(0, parent_pgrp))
1823                 perror_msg("tcsetpgrp");
1824
1825         /* return exit status if called with "-c" */
1826         if (input == NULL && WIFEXITED(status))
1827                 return WEXITSTATUS(status);
1828
1829         return 0;
1830 }
1831
1832
1833 #ifdef BB_FEATURE_CLEAN_UP
1834 void free_memory(void)
1835 {
1836         if (cwd)
1837                 free(cwd);
1838         if (local_pending_command)
1839                 free(local_pending_command);
1840
1841         if (job_list.fg && !job_list.fg->running_progs) {
1842                 remove_job(&job_list, job_list.fg);
1843         }
1844 }
1845 #endif
1846
1847
1848 int shell_main(int argc_l, char **argv_l)
1849 {
1850         int opt, interactive=FALSE;
1851         FILE *input = stdin;
1852         argc = argc_l;
1853         argv = argv_l;
1854
1855         /* These variables need re-initializing when recursing */
1856         shell_context = 0;
1857         cwd=NULL;
1858         local_pending_command = NULL;
1859         close_me_head = NULL;
1860         job_list.head = NULL;
1861         job_list.fg = NULL;
1862 #ifdef BB_FEATURE_SH_ENVIRONMENT
1863         last_bg_pid=1;
1864         last_return_code=1;
1865         show_x_trace=FALSE;
1866 #endif
1867
1868         if (argv[0] && argv[0][0] == '-') {
1869                 FILE *prof_input;
1870                 prof_input = fopen("/etc/profile", "r");
1871                 if (!prof_input) {
1872                         printf( "Couldn't open file '/etc/profile'\n");
1873                 } else {
1874                         int tmp_fd = fileno(prof_input);
1875                         mark_open(tmp_fd);
1876                         /* Now run the file */
1877                         busy_loop(prof_input);
1878                         fclose(prof_input);
1879                         mark_closed(tmp_fd);
1880                 }
1881         }
1882
1883         while ((opt = getopt(argc_l, argv_l, "cxi")) > 0) {
1884                 switch (opt) {
1885                         case 'c':
1886                                 input = NULL;
1887                                 if (local_pending_command != 0)
1888                                         error_msg_and_die("multiple -c arguments");
1889                                 local_pending_command = xstrdup(argv[optind]);
1890                                 optind++;
1891                                 argv = argv+optind;
1892                                 break;
1893 #ifdef BB_FEATURE_SH_ENVIRONMENT
1894                         case 'x':
1895                                 show_x_trace = TRUE;
1896                                 break;
1897 #endif
1898                         case 'i':
1899                                 interactive = TRUE;
1900                                 break;
1901                         default:
1902                                 show_usage();
1903                 }
1904         }
1905         /* A shell is interactive if the `-i' flag was given, or if all of
1906          * the following conditions are met:
1907          *        no -c command
1908          *    no arguments remaining or the -s flag given
1909          *    standard input is a terminal
1910          *    standard output is a terminal
1911          *    Refer to Posix.2, the description of the `sh' utility. */
1912         if (argv[optind]==NULL && input==stdin &&
1913                         isatty(fileno(stdin)) && isatty(fileno(stdout))) {
1914                 interactive=TRUE;
1915         }
1916         if (interactive==TRUE) {
1917                 //printf( "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
1918                 /* Looks like they want an interactive shell */
1919                 printf( "\n\nBusyBox v%s (%s) Built-in shell (lash)\n", BB_VER, BB_BT);
1920                 printf( "Enter 'help' for a list of built-in commands.\n\n");
1921         } else if (local_pending_command==NULL) {
1922                 //printf( "optind=%d  argv[optind]='%s'\n", optind, argv[optind]);
1923                 input = xfopen(argv[optind], "r");
1924                 mark_open(fileno(input));  /* be lazy, never mark this closed */
1925         }
1926
1927         /* initialize the cwd -- this is never freed...*/
1928         cwd=(char*)xmalloc(sizeof(char)*MAX_LINE+1);
1929         getcwd(cwd, sizeof(char)*MAX_LINE);
1930
1931 #ifdef BB_FEATURE_CLEAN_UP
1932         atexit(free_memory);
1933 #endif
1934
1935 #ifdef BB_FEATURE_COMMAND_EDITING
1936         cmdedit_set_initial_prompt();
1937 #else
1938         PS1 = NULL;
1939         PS2 = "> ";
1940 #endif
1941
1942         return (busy_loop(input));
1943 }
1944