run-command.c

   1 #include "cache.h"
   2 #include "run-command.h"
   3 #include "exec_cmd.h"
   4 #include "sigchain.h"
   5 #include "argv-array.h"
   6
   7 #ifndef SHELL_PATH
   8 # define SHELL_PATH "/bin/sh"
   9 #endif
  10
  11 struct child_to_clean {
  12         pid_t pid;
  13         struct child_to_clean *next;
  14 };
  15 static struct child_to_clean *children_to_clean;
  16 static int installed_child_cleanup_handler;
  17
  18 static void cleanup_children(int sig)
  19 {
  20         while (children_to_clean) {
  21                 struct child_to_clean *p = children_to_clean;
  22                 children_to_clean = p->next;
  23                 kill(p->pid, sig);
  24                 free(p);
  25         }
  26 }
  27
  28 static void cleanup_children_on_signal(int sig)
  29 {
  30         cleanup_children(sig);
  31         sigchain_pop(sig);
  32         raise(sig);
  33 }
  34
  35 static void cleanup_children_on_exit(void)
  36 {
  37         cleanup_children(SIGTERM);
  38 }
  39
  40 static void mark_child_for_cleanup(pid_t pid)
  41 {
  42         struct child_to_clean *p = xmalloc(sizeof(*p));
  43         p->pid = pid;
  44         p->next = children_to_clean;
  45         children_to_clean = p;
  46
  47         if (!installed_child_cleanup_handler) {
  48                 atexit(cleanup_children_on_exit);
  49                 sigchain_push_common(cleanup_children_on_signal);
  50                 installed_child_cleanup_handler = 1;
  51         }
  52 }
  53
  54 static void clear_child_for_cleanup(pid_t pid)
  55 {
  56         struct child_to_clean **last, *p;
  57
  58         last = &children_to_clean;
  59         for (p = children_to_clean; p; p = p->next) {
  60                 if (p->pid == pid) {
  61                         *last = p->next;
  62                         free(p);
  63                         return;
  64                 }
  65         }
  66 }
  67
  68 static inline void close_pair(int fd[2])
  69 {
  70         close(fd[0]);
  71         close(fd[1]);
  72 }
  73
  74 #ifndef WIN32
  75 static inline void dup_devnull(int to)
  76 {
  77         int fd = open("/dev/null", O_RDWR);
  78         dup2(fd, to);
  79         close(fd);
  80 }
  81 #endif
  82
  83 static const char **prepare_shell_cmd(const char **argv)
  84 {
  85         int argc, nargc = 0;
  86         const char **nargv;
  87
  88         for (argc = 0; argv[argc]; argc++)
  89                 ; /* just counting */
  90         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
  91         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
  92
  93         if (argc < 1)
  94                 die("BUG: shell command is empty");
  95
  96         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
  97                 nargv[nargc++] = SHELL_PATH;
  98                 nargv[nargc++] = "-c";
  99
 100                 if (argc < 2)
 101                         nargv[nargc++] = argv[0];
 102                 else {
 103                         struct strbuf arg0 = STRBUF_INIT;
 104                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 105                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
 106                 }
 107         }
 108
 109         for (argc = 0; argv[argc]; argc++)
 110                 nargv[nargc++] = argv[argc];
 111         nargv[nargc] = NULL;
 112
 113         return nargv;
 114 }
 115
 116 #ifndef WIN32
 117 static int execv_shell_cmd(const char **argv)
 118 {
 119         const char **nargv = prepare_shell_cmd(argv);
 120         trace_argv_printf(nargv, "trace: exec:");
 121         execvp(nargv[0], (char **)nargv);
 122         free(nargv);
 123         return -1;
 124 }
 125 #endif
 126
 127 #ifndef WIN32
 128 static int child_err = 2;
 129 static int child_notifier = -1;
 130
 131 static void notify_parent(void)
 132 {
 133         /*
 134          * execvp failed.  If possible, we'd like to let start_command
 135          * know, so failures like ENOENT can be handled right away; but
 136          * otherwise, finish_command will still report the error.
 137          */
 138         xwrite(child_notifier, "", 1);
 139 }
 140
 141 static NORETURN void die_child(const char *err, va_list params)
 142 {
 143         vwritef(child_err, "fatal: ", err, params);
 144         exit(128);
 145 }
 146
 147 static void error_child(const char *err, va_list params)
 148 {
 149         vwritef(child_err, "error: ", err, params);
 150 }
 151 #endif
 152
 153 static inline void set_cloexec(int fd)
 154 {
 155         int flags = fcntl(fd, F_GETFD);
 156         if (flags >= 0)
 157                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 158 }
 159
 160 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 161 {
 162         int status, code = -1;
 163         pid_t waiting;
 164         int failed_errno = 0;
 165
 166         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 167                 ;       /* nothing */
 168
 169         if (waiting < 0) {
 170                 failed_errno = errno;
 171                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 172         } else if (waiting != pid) {
 173                 error("waitpid is confused (%s)", argv0);
 174         } else if (WIFSIGNALED(status)) {
 175                 code = WTERMSIG(status);
 176                 error("%s died of signal %d", argv0, code);
 177                 /*
 178                  * This return value is chosen so that code & 0xff
 179                  * mimics the exit code that a POSIX shell would report for
 180                  * a program that died from this signal.
 181                  */
 182                 code -= 128;
 183         } else if (WIFEXITED(status)) {
 184                 code = WEXITSTATUS(status);
 185                 /*
 186                  * Convert special exit code when execvp failed.
 187                  */
 188                 if (code == 127) {
 189                         code = -1;
 190                         failed_errno = ENOENT;
 191                 }
 192         } else {
 193                 error("waitpid is confused (%s)", argv0);
 194         }
 195
 196         clear_child_for_cleanup(pid);
 197
 198         errno = failed_errno;
 199         return code;
 200 }
 201
 202 int start_command(struct child_process *cmd)
 203 {
 204         int need_in, need_out, need_err;
 205         int fdin[2], fdout[2], fderr[2];
 206         int failed_errno = failed_errno;
 207
 208         /*
 209          * In case of errors we must keep the promise to close FDs
 210          * that have been passed in via ->in and ->out.
 211          */
 212
 213         need_in = !cmd->no_stdin && cmd->in < 0;
 214         if (need_in) {
 215                 if (pipe(fdin) < 0) {
 216                         failed_errno = errno;
 217                         if (cmd->out > 0)
 218                                 close(cmd->out);
 219                         goto fail_pipe;
 220                 }
 221                 cmd->in = fdin[1];
 222         }
 223
 224         need_out = !cmd->no_stdout
 225                 && !cmd->stdout_to_stderr
 226                 && cmd->out < 0;
 227         if (need_out) {
 228                 if (pipe(fdout) < 0) {
 229                         failed_errno = errno;
 230                         if (need_in)
 231                                 close_pair(fdin);
 232                         else if (cmd->in)
 233                                 close(cmd->in);
 234                         goto fail_pipe;
 235                 }
 236                 cmd->out = fdout[0];
 237         }
 238
 239         need_err = !cmd->no_stderr && cmd->err < 0;
 240         if (need_err) {
 241                 if (pipe(fderr) < 0) {
 242                         failed_errno = errno;
 243                         if (need_in)
 244                                 close_pair(fdin);
 245                         else if (cmd->in)
 246                                 close(cmd->in);
 247                         if (need_out)
 248                                 close_pair(fdout);
 249                         else if (cmd->out)
 250                                 close(cmd->out);
 251 fail_pipe:
 252                         error("cannot create pipe for %s: %s",
 253                                 cmd->argv[0], strerror(failed_errno));
 254                         errno = failed_errno;
 255                         return -1;
 256                 }
 257                 cmd->err = fderr[0];
 258         }
 259
 260         trace_argv_printf(cmd->argv, "trace: run_command:");
 261         fflush(NULL);
 262
 263 #ifndef WIN32
 264 {
 265         int notify_pipe[2];
 266         if (pipe(notify_pipe))
 267                 notify_pipe[0] = notify_pipe[1] = -1;
 268
 269         cmd->pid = fork();
 270         if (!cmd->pid) {
 271                 /*
 272                  * Redirect the channel to write syscall error messages to
 273                  * before redirecting the process's stderr so that all die()
 274                  * in subsequent call paths use the parent's stderr.
 275                  */
 276                 if (cmd->no_stderr || need_err) {
 277                         child_err = dup(2);
 278                         set_cloexec(child_err);
 279                 }
 280                 set_die_routine(die_child);
 281                 set_error_routine(error_child);
 282
 283                 close(notify_pipe[0]);
 284                 set_cloexec(notify_pipe[1]);
 285                 child_notifier = notify_pipe[1];
 286                 atexit(notify_parent);
 287
 288                 if (cmd->no_stdin)
 289                         dup_devnull(0);
 290                 else if (need_in) {
 291                         dup2(fdin[0], 0);
 292                         close_pair(fdin);
 293                 } else if (cmd->in) {
 294                         dup2(cmd->in, 0);
 295                         close(cmd->in);
 296                 }
 297
 298                 if (cmd->no_stderr)
 299                         dup_devnull(2);
 300                 else if (need_err) {
 301                         dup2(fderr[1], 2);
 302                         close_pair(fderr);
 303                 } else if (cmd->err > 1) {
 304                         dup2(cmd->err, 2);
 305                         close(cmd->err);
 306                 }
 307
 308                 if (cmd->no_stdout)
 309                         dup_devnull(1);
 310                 else if (cmd->stdout_to_stderr)
 311                         dup2(2, 1);
 312                 else if (need_out) {
 313                         dup2(fdout[1], 1);
 314                         close_pair(fdout);
 315                 } else if (cmd->out > 1) {
 316                         dup2(cmd->out, 1);
 317                         close(cmd->out);
 318                 }
 319
 320                 if (cmd->dir && chdir(cmd->dir))
 321                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 322                             cmd->dir);
 323                 if (cmd->env) {
 324                         for (; *cmd->env; cmd->env++) {
 325                                 if (strchr(*cmd->env, '='))
 326                                         putenv((char *)*cmd->env);
 327                                 else
 328                                         unsetenv(*cmd->env);
 329                         }
 330                 }
 331                 if (cmd->preexec_cb) {
 332                         /*
 333                          * We cannot predict what the pre-exec callback does.
 334                          * Forgo parent notification.
 335                          */
 336                         close(child_notifier);
 337                         child_notifier = -1;
 338
 339                         cmd->preexec_cb();
 340                 }
 341                 if (cmd->git_cmd) {
 342                         execv_git_cmd(cmd->argv);
 343                 } else if (cmd->use_shell) {
 344                         execv_shell_cmd(cmd->argv);
 345                 } else {
 346                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 347                 }
 348                 if (errno == ENOENT) {
 349                         if (!cmd->silent_exec_failure)
 350                                 error("cannot run %s: %s", cmd->argv[0],
 351                                         strerror(ENOENT));
 352                         exit(127);
 353                 } else {
 354                         die_errno("cannot exec '%s'", cmd->argv[0]);
 355                 }
 356         }
 357         if (cmd->pid < 0)
 358                 error("cannot fork() for %s: %s", cmd->argv[0],
 359                         strerror(failed_errno = errno));
 360         else if (cmd->clean_on_exit)
 361                 mark_child_for_cleanup(cmd->pid);
 362
 363         /*
 364          * Wait for child's execvp. If the execvp succeeds (or if fork()
 365          * failed), EOF is seen immediately by the parent. Otherwise, the
 366          * child process sends a single byte.
 367          * Note that use of this infrastructure is completely advisory,
 368          * therefore, we keep error checks minimal.
 369          */
 370         close(notify_pipe[1]);
 371         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 372                 /*
 373                  * At this point we know that fork() succeeded, but execvp()
 374                  * failed. Errors have been reported to our stderr.
 375                  */
 376                 wait_or_whine(cmd->pid, cmd->argv[0],
 377                               cmd->silent_exec_failure);
 378                 failed_errno = errno;
 379                 cmd->pid = -1;
 380         }
 381         close(notify_pipe[0]);
 382
 383 }
 384 #else
 385 {
 386         int fhin = 0, fhout = 1, fherr = 2;
 387         const char **sargv = cmd->argv;
 388         char **env = environ;
 389
 390         if (cmd->no_stdin)
 391                 fhin = open("/dev/null", O_RDWR);
 392         else if (need_in)
 393                 fhin = dup(fdin[0]);
 394         else if (cmd->in)
 395                 fhin = dup(cmd->in);
 396
 397         if (cmd->no_stderr)
 398                 fherr = open("/dev/null", O_RDWR);
 399         else if (need_err)
 400                 fherr = dup(fderr[1]);
 401         else if (cmd->err > 2)
 402                 fherr = dup(cmd->err);
 403
 404         if (cmd->no_stdout)
 405                 fhout = open("/dev/null", O_RDWR);
 406         else if (cmd->stdout_to_stderr)
 407                 fhout = dup(fherr);
 408         else if (need_out)
 409                 fhout = dup(fdout[1]);
 410         else if (cmd->out > 1)
 411                 fhout = dup(cmd->out);
 412
 413         if (cmd->env)
 414                 env = make_augmented_environ(cmd->env);
 415
 416         if (cmd->git_cmd) {
 417                 cmd->argv = prepare_git_cmd(cmd->argv);
 418         } else if (cmd->use_shell) {
 419                 cmd->argv = prepare_shell_cmd(cmd->argv);
 420         }
 421
 422         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 423                                   fhin, fhout, fherr);
 424         failed_errno = errno;
 425         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 426                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 427         if (cmd->clean_on_exit && cmd->pid >= 0)
 428                 mark_child_for_cleanup(cmd->pid);
 429
 430         if (cmd->env)
 431                 free_environ(env);
 432         if (cmd->git_cmd)
 433                 free(cmd->argv);
 434
 435         cmd->argv = sargv;
 436         if (fhin != 0)
 437                 close(fhin);
 438         if (fhout != 1)
 439                 close(fhout);
 440         if (fherr != 2)
 441                 close(fherr);
 442 }
 443 #endif
 444
 445         if (cmd->pid < 0) {
 446                 if (need_in)
 447                         close_pair(fdin);
 448                 else if (cmd->in)
 449                         close(cmd->in);
 450                 if (need_out)
 451                         close_pair(fdout);
 452                 else if (cmd->out)
 453                         close(cmd->out);
 454                 if (need_err)
 455                         close_pair(fderr);
 456                 else if (cmd->err)
 457                         close(cmd->err);
 458                 errno = failed_errno;
 459                 return -1;
 460         }
 461
 462         if (need_in)
 463                 close(fdin[0]);
 464         else if (cmd->in)
 465                 close(cmd->in);
 466
 467         if (need_out)
 468                 close(fdout[1]);
 469         else if (cmd->out)
 470                 close(cmd->out);
 471
 472         if (need_err)
 473                 close(fderr[1]);
 474         else if (cmd->err)
 475                 close(cmd->err);
 476
 477         return 0;
 478 }
 479
 480 int finish_command(struct child_process *cmd)
 481 {
 482         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 483 }
 484
 485 int run_command(struct child_process *cmd)
 486 {
 487         int code = start_command(cmd);
 488         if (code)
 489                 return code;
 490         return finish_command(cmd);
 491 }
 492
 493 static void prepare_run_command_v_opt(struct child_process *cmd,
 494                                       const char **argv,
 495                                       int opt)
 496 {
 497         memset(cmd, 0, sizeof(*cmd));
 498         cmd->argv = argv;
 499         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 500         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 501         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 502         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 503         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 504         cmd->clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 505 }
 506
 507 int run_command_v_opt(const char **argv, int opt)
 508 {
 509         struct child_process cmd;
 510         prepare_run_command_v_opt(&cmd, argv, opt);
 511         return run_command(&cmd);
 512 }
 513
 514 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 515 {
 516         struct child_process cmd;
 517         prepare_run_command_v_opt(&cmd, argv, opt);
 518         cmd.dir = dir;
 519         cmd.env = env;
 520         return run_command(&cmd);
 521 }
 522
 523 #ifndef NO_PTHREADS
 524 static pthread_t main_thread;
 525 static int main_thread_set;
 526 static pthread_key_t async_key;
 527
 528 static void *run_thread(void *data)
 529 {
 530         struct async *async = data;
 531         intptr_t ret;
 532
 533         pthread_setspecific(async_key, async);
 534         ret = async->proc(async->proc_in, async->proc_out, async->data);
 535         return (void *)ret;
 536 }
 537
 538 static NORETURN void die_async(const char *err, va_list params)
 539 {
 540         vreportf("fatal: ", err, params);
 541
 542         if (!pthread_equal(main_thread, pthread_self())) {
 543                 struct async *async = pthread_getspecific(async_key);
 544                 if (async->proc_in >= 0)
 545                         close(async->proc_in);
 546                 if (async->proc_out >= 0)
 547                         close(async->proc_out);
 548                 pthread_exit((void *)128);
 549         }
 550
 551         exit(128);
 552 }
 553 #endif
 554
 555 int start_async(struct async *async)
 556 {
 557         int need_in, need_out;
 558         int fdin[2], fdout[2];
 559         int proc_in, proc_out;
 560
 561         need_in = async->in < 0;
 562         if (need_in) {
 563                 if (pipe(fdin) < 0) {
 564                         if (async->out > 0)
 565                                 close(async->out);
 566                         return error("cannot create pipe: %s", strerror(errno));
 567                 }
 568                 async->in = fdin[1];
 569         }
 570
 571         need_out = async->out < 0;
 572         if (need_out) {
 573                 if (pipe(fdout) < 0) {
 574                         if (need_in)
 575                                 close_pair(fdin);
 576                         else if (async->in)
 577                                 close(async->in);
 578                         return error("cannot create pipe: %s", strerror(errno));
 579                 }
 580                 async->out = fdout[0];
 581         }
 582
 583         if (need_in)
 584                 proc_in = fdin[0];
 585         else if (async->in)
 586                 proc_in = async->in;
 587         else
 588                 proc_in = -1;
 589
 590         if (need_out)
 591                 proc_out = fdout[1];
 592         else if (async->out)
 593                 proc_out = async->out;
 594         else
 595                 proc_out = -1;
 596
 597 #ifdef NO_PTHREADS
 598         /* Flush stdio before fork() to avoid cloning buffers */
 599         fflush(NULL);
 600
 601         async->pid = fork();
 602         if (async->pid < 0) {
 603                 error("fork (async) failed: %s", strerror(errno));
 604                 goto error;
 605         }
 606         if (!async->pid) {
 607                 if (need_in)
 608                         close(fdin[1]);
 609                 if (need_out)
 610                         close(fdout[0]);
 611                 exit(!!async->proc(proc_in, proc_out, async->data));
 612         }
 613
 614         mark_child_for_cleanup(async->pid);
 615
 616         if (need_in)
 617                 close(fdin[0]);
 618         else if (async->in)
 619                 close(async->in);
 620
 621         if (need_out)
 622                 close(fdout[1]);
 623         else if (async->out)
 624                 close(async->out);
 625 #else
 626         if (!main_thread_set) {
 627                 /*
 628                  * We assume that the first time that start_async is called
 629                  * it is from the main thread.
 630                  */
 631                 main_thread_set = 1;
 632                 main_thread = pthread_self();
 633                 pthread_key_create(&async_key, NULL);
 634                 set_die_routine(die_async);
 635         }
 636
 637         if (proc_in >= 0)
 638                 set_cloexec(proc_in);
 639         if (proc_out >= 0)
 640                 set_cloexec(proc_out);
 641         async->proc_in = proc_in;
 642         async->proc_out = proc_out;
 643         {
 644                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 645                 if (err) {
 646                         error("cannot create thread: %s", strerror(err));
 647                         goto error;
 648                 }
 649         }
 650 #endif
 651         return 0;
 652
 653 error:
 654         if (need_in)
 655                 close_pair(fdin);
 656         else if (async->in)
 657                 close(async->in);
 658
 659         if (need_out)
 660                 close_pair(fdout);
 661         else if (async->out)
 662                 close(async->out);
 663         return -1;
 664 }
 665
 666 int finish_async(struct async *async)
 667 {
 668 #ifdef NO_PTHREADS
 669         return wait_or_whine(async->pid, "child process", 0);
 670 #else
 671         void *ret = (void *)(intptr_t)(-1);
 672
 673         if (pthread_join(async->tid, &ret))
 674                 error("pthread_join failed");
 675         return (int)(intptr_t)ret;
 676 #endif
 677 }
 678
 679 int run_hook(const char *index_file, const char *name, ...)
 680 {
 681         struct child_process hook;
 682         struct argv_array argv = ARGV_ARRAY_INIT;
 683         const char *p, *env[2];
 684         char index[PATH_MAX];
 685         va_list args;
 686         int ret;
 687
 688         if (access(git_path("hooks/%s", name), X_OK) < 0)
 689                 return 0;
 690
 691         va_start(args, name);
 692         argv_array_push(&argv, git_path("hooks/%s", name));
 693         while ((p = va_arg(args, const char *)))
 694                 argv_array_push(&argv, p);
 695         va_end(args);
 696
 697         memset(&hook, 0, sizeof(hook));
 698         hook.argv = argv.argv;
 699         hook.no_stdin = 1;
 700         hook.stdout_to_stderr = 1;
 701         if (index_file) {
 702                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 703                 env[0] = index;
 704                 env[1] = NULL;
 705                 hook.env = env;
 706         }
 707
 708         ret = run_command(&hook);
 709         argv_array_clear(&argv);
 710         return ret;
 711 }