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