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 void child_process_init(struct child_process *child)
   8 {
   9         memset(child, 0, sizeof(*child));
  10         argv_array_init(&child->args);
  11         argv_array_init(&child->env_array);
  12 }
  13
  14 void child_process_clear(struct child_process *child)
  15 {
  16         argv_array_clear(&child->args);
  17         argv_array_clear(&child->env_array);
  18 }
  19
  20 struct child_to_clean {
  21         pid_t pid;
  22         struct child_to_clean *next;
  23 };
  24 static struct child_to_clean *children_to_clean;
  25 static int installed_child_cleanup_handler;
  26
  27 static void cleanup_children(int sig, int in_signal)
  28 {
  29         while (children_to_clean) {
  30                 struct child_to_clean *p = children_to_clean;
  31                 children_to_clean = p->next;
  32                 kill(p->pid, sig);
  33                 if (!in_signal)
  34                         free(p);
  35         }
  36 }
  37
  38 static void cleanup_children_on_signal(int sig)
  39 {
  40         cleanup_children(sig, 1);
  41         sigchain_pop(sig);
  42         raise(sig);
  43 }
  44
  45 static void cleanup_children_on_exit(void)
  46 {
  47         cleanup_children(SIGTERM, 0);
  48 }
  49
  50 static void mark_child_for_cleanup(pid_t pid)
  51 {
  52         struct child_to_clean *p = xmalloc(sizeof(*p));
  53         p->pid = pid;
  54         p->next = children_to_clean;
  55         children_to_clean = p;
  56
  57         if (!installed_child_cleanup_handler) {
  58                 atexit(cleanup_children_on_exit);
  59                 sigchain_push_common(cleanup_children_on_signal);
  60                 installed_child_cleanup_handler = 1;
  61         }
  62 }
  63
  64 static void clear_child_for_cleanup(pid_t pid)
  65 {
  66         struct child_to_clean **pp;
  67
  68         for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
  69                 struct child_to_clean *clean_me = *pp;
  70
  71                 if (clean_me->pid == pid) {
  72                         *pp = clean_me->next;
  73                         free(clean_me);
  74                         return;
  75                 }
  76         }
  77 }
  78
  79 static inline void close_pair(int fd[2])
  80 {
  81         close(fd[0]);
  82         close(fd[1]);
  83 }
  84
  85 #ifndef GIT_WINDOWS_NATIVE
  86 static inline void dup_devnull(int to)
  87 {
  88         int fd = open("/dev/null", O_RDWR);
  89         if (fd < 0)
  90                 die_errno(_("open /dev/null failed"));
  91         if (dup2(fd, to) < 0)
  92                 die_errno(_("dup2(%d,%d) failed"), fd, to);
  93         close(fd);
  94 }
  95 #endif
  96
  97 static char *locate_in_PATH(const char *file)
  98 {
  99         const char *p = getenv("PATH");
 100         struct strbuf buf = STRBUF_INIT;
 101
 102         if (!p || !*p)
 103                 return NULL;
 104
 105         while (1) {
 106                 const char *end = strchrnul(p, ':');
 107
 108                 strbuf_reset(&buf);
 109
 110                 /* POSIX specifies an empty entry as the current directory. */
 111                 if (end != p) {
 112                         strbuf_add(&buf, p, end - p);
 113                         strbuf_addch(&buf, '/');
 114                 }
 115                 strbuf_addstr(&buf, file);
 116
 117                 if (!access(buf.buf, F_OK))
 118                         return strbuf_detach(&buf, NULL);
 119
 120                 if (!*end)
 121                         break;
 122                 p = end + 1;
 123         }
 124
 125         strbuf_release(&buf);
 126         return NULL;
 127 }
 128
 129 static int exists_in_PATH(const char *file)
 130 {
 131         char *r = locate_in_PATH(file);
 132         free(r);
 133         return r != NULL;
 134 }
 135
 136 int sane_execvp(const char *file, char * const argv[])
 137 {
 138         if (!execvp(file, argv))
 139                 return 0; /* cannot happen ;-) */
 140
 141         /*
 142          * When a command can't be found because one of the directories
 143          * listed in $PATH is unsearchable, execvp reports EACCES, but
 144          * careful usability testing (read: analysis of occasional bug
 145          * reports) reveals that "No such file or directory" is more
 146          * intuitive.
 147          *
 148          * We avoid commands with "/", because execvp will not do $PATH
 149          * lookups in that case.
 150          *
 151          * The reassignment of EACCES to errno looks like a no-op below,
 152          * but we need to protect against exists_in_PATH overwriting errno.
 153          */
 154         if (errno == EACCES && !strchr(file, '/'))
 155                 errno = exists_in_PATH(file) ? EACCES : ENOENT;
 156         else if (errno == ENOTDIR && !strchr(file, '/'))
 157                 errno = ENOENT;
 158         return -1;
 159 }
 160
 161 static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
 162 {
 163         if (!argv[0])
 164                 die("BUG: shell command is empty");
 165
 166         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 167 #ifndef GIT_WINDOWS_NATIVE
 168                 argv_array_push(out, SHELL_PATH);
 169 #else
 170                 argv_array_push(out, "sh");
 171 #endif
 172                 argv_array_push(out, "-c");
 173
 174                 /*
 175                  * If we have no extra arguments, we do not even need to
 176                  * bother with the "$@" magic.
 177                  */
 178                 if (!argv[1])
 179                         argv_array_push(out, argv[0]);
 180                 else
 181                         argv_array_pushf(out, "%s \"$@\"", argv[0]);
 182         }
 183
 184         argv_array_pushv(out, argv);
 185         return out->argv;
 186 }
 187
 188 #ifndef GIT_WINDOWS_NATIVE
 189 static int execv_shell_cmd(const char **argv)
 190 {
 191         struct argv_array nargv = ARGV_ARRAY_INIT;
 192         prepare_shell_cmd(&nargv, argv);
 193         trace_argv_printf(nargv.argv, "trace: exec:");
 194         sane_execvp(nargv.argv[0], (char **)nargv.argv);
 195         argv_array_clear(&nargv);
 196         return -1;
 197 }
 198 #endif
 199
 200 #ifndef GIT_WINDOWS_NATIVE
 201 static int child_notifier = -1;
 202
 203 static void notify_parent(void)
 204 {
 205         /*
 206          * execvp failed.  If possible, we'd like to let start_command
 207          * know, so failures like ENOENT can be handled right away; but
 208          * otherwise, finish_command will still report the error.
 209          */
 210         xwrite(child_notifier, "", 1);
 211 }
 212 #endif
 213
 214 static inline void set_cloexec(int fd)
 215 {
 216         int flags = fcntl(fd, F_GETFD);
 217         if (flags >= 0)
 218                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 219 }
 220
 221 static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
 222 {
 223         int status, code = -1;
 224         pid_t waiting;
 225         int failed_errno = 0;
 226
 227         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 228                 ;       /* nothing */
 229         if (in_signal)
 230                 return 0;
 231
 232         if (waiting < 0) {
 233                 failed_errno = errno;
 234                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 235         } else if (waiting != pid) {
 236                 error("waitpid is confused (%s)", argv0);
 237         } else if (WIFSIGNALED(status)) {
 238                 code = WTERMSIG(status);
 239                 if (code != SIGINT && code != SIGQUIT)
 240                         error("%s died of signal %d", argv0, code);
 241                 /*
 242                  * This return value is chosen so that code & 0xff
 243                  * mimics the exit code that a POSIX shell would report for
 244                  * a program that died from this signal.
 245                  */
 246                 code += 128;
 247         } else if (WIFEXITED(status)) {
 248                 code = WEXITSTATUS(status);
 249                 /*
 250                  * Convert special exit code when execvp failed.
 251                  */
 252                 if (code == 127) {
 253                         code = -1;
 254                         failed_errno = ENOENT;
 255                 }
 256         } else {
 257                 error("waitpid is confused (%s)", argv0);
 258         }
 259
 260         clear_child_for_cleanup(pid);
 261
 262         errno = failed_errno;
 263         return code;
 264 }
 265
 266 int start_command(struct child_process *cmd)
 267 {
 268         int need_in, need_out, need_err;
 269         int fdin[2], fdout[2], fderr[2];
 270         int failed_errno;
 271         char *str;
 272
 273         if (!cmd->argv)
 274                 cmd->argv = cmd->args.argv;
 275         if (!cmd->env)
 276                 cmd->env = cmd->env_array.argv;
 277
 278         /*
 279          * In case of errors we must keep the promise to close FDs
 280          * that have been passed in via ->in and ->out.
 281          */
 282
 283         need_in = !cmd->no_stdin && cmd->in < 0;
 284         if (need_in) {
 285                 if (pipe(fdin) < 0) {
 286                         failed_errno = errno;
 287                         if (cmd->out > 0)
 288                                 close(cmd->out);
 289                         str = "standard input";
 290                         goto fail_pipe;
 291                 }
 292                 cmd->in = fdin[1];
 293         }
 294
 295         need_out = !cmd->no_stdout
 296                 && !cmd->stdout_to_stderr
 297                 && cmd->out < 0;
 298         if (need_out) {
 299                 if (pipe(fdout) < 0) {
 300                         failed_errno = errno;
 301                         if (need_in)
 302                                 close_pair(fdin);
 303                         else if (cmd->in)
 304                                 close(cmd->in);
 305                         str = "standard output";
 306                         goto fail_pipe;
 307                 }
 308                 cmd->out = fdout[0];
 309         }
 310
 311         need_err = !cmd->no_stderr && cmd->err < 0;
 312         if (need_err) {
 313                 if (pipe(fderr) < 0) {
 314                         failed_errno = errno;
 315                         if (need_in)
 316                                 close_pair(fdin);
 317                         else if (cmd->in)
 318                                 close(cmd->in);
 319                         if (need_out)
 320                                 close_pair(fdout);
 321                         else if (cmd->out)
 322                                 close(cmd->out);
 323                         str = "standard error";
 324 fail_pipe:
 325                         error("cannot create %s pipe for %s: %s",
 326                                 str, cmd->argv[0], strerror(failed_errno));
 327                         child_process_clear(cmd);
 328                         errno = failed_errno;
 329                         return -1;
 330                 }
 331                 cmd->err = fderr[0];
 332         }
 333
 334         trace_argv_printf(cmd->argv, "trace: run_command:");
 335         fflush(NULL);
 336
 337 #ifndef GIT_WINDOWS_NATIVE
 338 {
 339         int notify_pipe[2];
 340         if (pipe(notify_pipe))
 341                 notify_pipe[0] = notify_pipe[1] = -1;
 342
 343         cmd->pid = fork();
 344         failed_errno = errno;
 345         if (!cmd->pid) {
 346                 /*
 347                  * Redirect the channel to write syscall error messages to
 348                  * before redirecting the process's stderr so that all die()
 349                  * in subsequent call paths use the parent's stderr.
 350                  */
 351                 if (cmd->no_stderr || need_err) {
 352                         int child_err = dup(2);
 353                         set_cloexec(child_err);
 354                         set_error_handle(fdopen(child_err, "w"));
 355                 }
 356
 357                 close(notify_pipe[0]);
 358                 set_cloexec(notify_pipe[1]);
 359                 child_notifier = notify_pipe[1];
 360                 atexit(notify_parent);
 361
 362                 if (cmd->no_stdin)
 363                         dup_devnull(0);
 364                 else if (need_in) {
 365                         dup2(fdin[0], 0);
 366                         close_pair(fdin);
 367                 } else if (cmd->in) {
 368                         dup2(cmd->in, 0);
 369                         close(cmd->in);
 370                 }
 371
 372                 if (cmd->no_stderr)
 373                         dup_devnull(2);
 374                 else if (need_err) {
 375                         dup2(fderr[1], 2);
 376                         close_pair(fderr);
 377                 } else if (cmd->err > 1) {
 378                         dup2(cmd->err, 2);
 379                         close(cmd->err);
 380                 }
 381
 382                 if (cmd->no_stdout)
 383                         dup_devnull(1);
 384                 else if (cmd->stdout_to_stderr)
 385                         dup2(2, 1);
 386                 else if (need_out) {
 387                         dup2(fdout[1], 1);
 388                         close_pair(fdout);
 389                 } else if (cmd->out > 1) {
 390                         dup2(cmd->out, 1);
 391                         close(cmd->out);
 392                 }
 393
 394                 if (cmd->dir && chdir(cmd->dir))
 395                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 396                             cmd->dir);
 397                 if (cmd->env) {
 398                         for (; *cmd->env; cmd->env++) {
 399                                 if (strchr(*cmd->env, '='))
 400                                         putenv((char *)*cmd->env);
 401                                 else
 402                                         unsetenv(*cmd->env);
 403                         }
 404                 }
 405                 if (cmd->git_cmd)
 406                         execv_git_cmd(cmd->argv);
 407                 else if (cmd->use_shell)
 408                         execv_shell_cmd(cmd->argv);
 409                 else
 410                         sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 411                 if (errno == ENOENT) {
 412                         if (!cmd->silent_exec_failure)
 413                                 error("cannot run %s: %s", cmd->argv[0],
 414                                         strerror(ENOENT));
 415                         exit(127);
 416                 } else {
 417                         die_errno("cannot exec '%s'", cmd->argv[0]);
 418                 }
 419         }
 420         if (cmd->pid < 0)
 421                 error("cannot fork() for %s: %s", cmd->argv[0],
 422                         strerror(errno));
 423         else if (cmd->clean_on_exit)
 424                 mark_child_for_cleanup(cmd->pid);
 425
 426         /*
 427          * Wait for child's execvp. If the execvp succeeds (or if fork()
 428          * failed), EOF is seen immediately by the parent. Otherwise, the
 429          * child process sends a single byte.
 430          * Note that use of this infrastructure is completely advisory,
 431          * therefore, we keep error checks minimal.
 432          */
 433         close(notify_pipe[1]);
 434         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 435                 /*
 436                  * At this point we know that fork() succeeded, but execvp()
 437                  * failed. Errors have been reported to our stderr.
 438                  */
 439                 wait_or_whine(cmd->pid, cmd->argv[0], 0);
 440                 failed_errno = errno;
 441                 cmd->pid = -1;
 442         }
 443         close(notify_pipe[0]);
 444 }
 445 #else
 446 {
 447         int fhin = 0, fhout = 1, fherr = 2;
 448         const char **sargv = cmd->argv;
 449         struct argv_array nargv = ARGV_ARRAY_INIT;
 450
 451         if (cmd->no_stdin)
 452                 fhin = open("/dev/null", O_RDWR);
 453         else if (need_in)
 454                 fhin = dup(fdin[0]);
 455         else if (cmd->in)
 456                 fhin = dup(cmd->in);
 457
 458         if (cmd->no_stderr)
 459                 fherr = open("/dev/null", O_RDWR);
 460         else if (need_err)
 461                 fherr = dup(fderr[1]);
 462         else if (cmd->err > 2)
 463                 fherr = dup(cmd->err);
 464
 465         if (cmd->no_stdout)
 466                 fhout = open("/dev/null", O_RDWR);
 467         else if (cmd->stdout_to_stderr)
 468                 fhout = dup(fherr);
 469         else if (need_out)
 470                 fhout = dup(fdout[1]);
 471         else if (cmd->out > 1)
 472                 fhout = dup(cmd->out);
 473
 474         if (cmd->git_cmd)
 475                 cmd->argv = prepare_git_cmd(&nargv, cmd->argv);
 476         else if (cmd->use_shell)
 477                 cmd->argv = prepare_shell_cmd(&nargv, cmd->argv);
 478
 479         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
 480                         cmd->dir, fhin, fhout, fherr);
 481         failed_errno = errno;
 482         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 483                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 484         if (cmd->clean_on_exit && cmd->pid >= 0)
 485                 mark_child_for_cleanup(cmd->pid);
 486
 487         argv_array_clear(&nargv);
 488         cmd->argv = sargv;
 489         if (fhin != 0)
 490                 close(fhin);
 491         if (fhout != 1)
 492                 close(fhout);
 493         if (fherr != 2)
 494                 close(fherr);
 495 }
 496 #endif
 497
 498         if (cmd->pid < 0) {
 499                 if (need_in)
 500                         close_pair(fdin);
 501                 else if (cmd->in)
 502                         close(cmd->in);
 503                 if (need_out)
 504                         close_pair(fdout);
 505                 else if (cmd->out)
 506                         close(cmd->out);
 507                 if (need_err)
 508                         close_pair(fderr);
 509                 else if (cmd->err)
 510                         close(cmd->err);
 511                 child_process_clear(cmd);
 512                 errno = failed_errno;
 513                 return -1;
 514         }
 515
 516         if (need_in)
 517                 close(fdin[0]);
 518         else if (cmd->in)
 519                 close(cmd->in);
 520
 521         if (need_out)
 522                 close(fdout[1]);
 523         else if (cmd->out)
 524                 close(cmd->out);
 525
 526         if (need_err)
 527                 close(fderr[1]);
 528         else if (cmd->err)
 529                 close(cmd->err);
 530
 531         return 0;
 532 }
 533
 534 int finish_command(struct child_process *cmd)
 535 {
 536         int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
 537         child_process_clear(cmd);
 538         return ret;
 539 }
 540
 541 int finish_command_in_signal(struct child_process *cmd)
 542 {
 543         return wait_or_whine(cmd->pid, cmd->argv[0], 1);
 544 }
 545
 546
 547 int run_command(struct child_process *cmd)
 548 {
 549         int code;
 550
 551         if (cmd->out < 0 || cmd->err < 0)
 552                 die("BUG: run_command with a pipe can cause deadlock");
 553
 554         code = start_command(cmd);
 555         if (code)
 556                 return code;
 557         return finish_command(cmd);
 558 }
 559
 560 int run_command_v_opt(const char **argv, int opt)
 561 {
 562         return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
 563 }
 564
 565 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 566 {
 567         struct child_process cmd = CHILD_PROCESS_INIT;
 568         cmd.argv = argv;
 569         cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 570         cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 571         cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 572         cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 573         cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 574         cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 575         cmd.dir = dir;
 576         cmd.env = env;
 577         return run_command(&cmd);
 578 }
 579
 580 #ifndef NO_PTHREADS
 581 static pthread_t main_thread;
 582 static int main_thread_set;
 583 static pthread_key_t async_key;
 584 static pthread_key_t async_die_counter;
 585
 586 static void *run_thread(void *data)
 587 {
 588         struct async *async = data;
 589         intptr_t ret;
 590
 591         pthread_setspecific(async_key, async);
 592         ret = async->proc(async->proc_in, async->proc_out, async->data);
 593         return (void *)ret;
 594 }
 595
 596 static NORETURN void die_async(const char *err, va_list params)
 597 {
 598         vreportf("fatal: ", err, params);
 599
 600         if (in_async()) {
 601                 struct async *async = pthread_getspecific(async_key);
 602                 if (async->proc_in >= 0)
 603                         close(async->proc_in);
 604                 if (async->proc_out >= 0)
 605                         close(async->proc_out);
 606                 pthread_exit((void *)128);
 607         }
 608
 609         exit(128);
 610 }
 611
 612 static int async_die_is_recursing(void)
 613 {
 614         void *ret = pthread_getspecific(async_die_counter);
 615         pthread_setspecific(async_die_counter, (void *)1);
 616         return ret != NULL;
 617 }
 618
 619 int in_async(void)
 620 {
 621         if (!main_thread_set)
 622                 return 0; /* no asyncs started yet */
 623         return !pthread_equal(main_thread, pthread_self());
 624 }
 625
 626 #else
 627
 628 static struct {
 629         void (**handlers)(void);
 630         size_t nr;
 631         size_t alloc;
 632 } git_atexit_hdlrs;
 633
 634 static int git_atexit_installed;
 635
 636 static void git_atexit_dispatch(void)
 637 {
 638         size_t i;
 639
 640         for (i=git_atexit_hdlrs.nr ; i ; i--)
 641                 git_atexit_hdlrs.handlers[i-1]();
 642 }
 643
 644 static void git_atexit_clear(void)
 645 {
 646         free(git_atexit_hdlrs.handlers);
 647         memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
 648         git_atexit_installed = 0;
 649 }
 650
 651 #undef atexit
 652 int git_atexit(void (*handler)(void))
 653 {
 654         ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
 655         git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
 656         if (!git_atexit_installed) {
 657                 if (atexit(&git_atexit_dispatch))
 658                         return -1;
 659                 git_atexit_installed = 1;
 660         }
 661         return 0;
 662 }
 663 #define atexit git_atexit
 664
 665 static int process_is_async;
 666 int in_async(void)
 667 {
 668         return process_is_async;
 669 }
 670
 671 #endif
 672
 673 int start_async(struct async *async)
 674 {
 675         int need_in, need_out;
 676         int fdin[2], fdout[2];
 677         int proc_in, proc_out;
 678
 679         need_in = async->in < 0;
 680         if (need_in) {
 681                 if (pipe(fdin) < 0) {
 682                         if (async->out > 0)
 683                                 close(async->out);
 684                         return error("cannot create pipe: %s", strerror(errno));
 685                 }
 686                 async->in = fdin[1];
 687         }
 688
 689         need_out = async->out < 0;
 690         if (need_out) {
 691                 if (pipe(fdout) < 0) {
 692                         if (need_in)
 693                                 close_pair(fdin);
 694                         else if (async->in)
 695                                 close(async->in);
 696                         return error("cannot create pipe: %s", strerror(errno));
 697                 }
 698                 async->out = fdout[0];
 699         }
 700
 701         if (need_in)
 702                 proc_in = fdin[0];
 703         else if (async->in)
 704                 proc_in = async->in;
 705         else
 706                 proc_in = -1;
 707
 708         if (need_out)
 709                 proc_out = fdout[1];
 710         else if (async->out)
 711                 proc_out = async->out;
 712         else
 713                 proc_out = -1;
 714
 715 #ifdef NO_PTHREADS
 716         /* Flush stdio before fork() to avoid cloning buffers */
 717         fflush(NULL);
 718
 719         async->pid = fork();
 720         if (async->pid < 0) {
 721                 error("fork (async) failed: %s", strerror(errno));
 722                 goto error;
 723         }
 724         if (!async->pid) {
 725                 if (need_in)
 726                         close(fdin[1]);
 727                 if (need_out)
 728                         close(fdout[0]);
 729                 git_atexit_clear();
 730                 process_is_async = 1;
 731                 exit(!!async->proc(proc_in, proc_out, async->data));
 732         }
 733
 734         mark_child_for_cleanup(async->pid);
 735
 736         if (need_in)
 737                 close(fdin[0]);
 738         else if (async->in)
 739                 close(async->in);
 740
 741         if (need_out)
 742                 close(fdout[1]);
 743         else if (async->out)
 744                 close(async->out);
 745 #else
 746         if (!main_thread_set) {
 747                 /*
 748                  * We assume that the first time that start_async is called
 749                  * it is from the main thread.
 750                  */
 751                 main_thread_set = 1;
 752                 main_thread = pthread_self();
 753                 pthread_key_create(&async_key, NULL);
 754                 pthread_key_create(&async_die_counter, NULL);
 755                 set_die_routine(die_async);
 756                 set_die_is_recursing_routine(async_die_is_recursing);
 757         }
 758
 759         if (proc_in >= 0)
 760                 set_cloexec(proc_in);
 761         if (proc_out >= 0)
 762                 set_cloexec(proc_out);
 763         async->proc_in = proc_in;
 764         async->proc_out = proc_out;
 765         {
 766                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 767                 if (err) {
 768                         error("cannot create thread: %s", strerror(err));
 769                         goto error;
 770                 }
 771         }
 772 #endif
 773         return 0;
 774
 775 error:
 776         if (need_in)
 777                 close_pair(fdin);
 778         else if (async->in)
 779                 close(async->in);
 780
 781         if (need_out)
 782                 close_pair(fdout);
 783         else if (async->out)
 784                 close(async->out);
 785         return -1;
 786 }
 787
 788 int finish_async(struct async *async)
 789 {
 790 #ifdef NO_PTHREADS
 791         return wait_or_whine(async->pid, "child process", 0);
 792 #else
 793         void *ret = (void *)(intptr_t)(-1);
 794
 795         if (pthread_join(async->tid, &ret))
 796                 error("pthread_join failed");
 797         return (int)(intptr_t)ret;
 798 #endif
 799 }
 800
 801 const char *find_hook(const char *name)
 802 {
 803         static struct strbuf path = STRBUF_INIT;
 804
 805         strbuf_reset(&path);
 806         strbuf_git_path(&path, "hooks/%s", name);
 807         if (access(path.buf, X_OK) < 0)
 808                 return NULL;
 809         return path.buf;
 810 }
 811
 812 int run_hook_ve(const char *const *env, const char *name, va_list args)
 813 {
 814         struct child_process hook = CHILD_PROCESS_INIT;
 815         const char *p;
 816
 817         p = find_hook(name);
 818         if (!p)
 819                 return 0;
 820
 821         argv_array_push(&hook.args, p);
 822         while ((p = va_arg(args, const char *)))
 823                 argv_array_push(&hook.args, p);
 824         hook.env = env;
 825         hook.no_stdin = 1;
 826         hook.stdout_to_stderr = 1;
 827
 828         return run_command(&hook);
 829 }
 830
 831 int run_hook_le(const char *const *env, const char *name, ...)
 832 {
 833         va_list args;
 834         int ret;
 835
 836         va_start(args, name);
 837         ret = run_hook_ve(env, name, args);
 838         va_end(args);
 839
 840         return ret;
 841 }
 842
 843 int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint)
 844 {
 845         cmd->out = -1;
 846         if (start_command(cmd) < 0)
 847                 return -1;
 848
 849         if (strbuf_read(buf, cmd->out, hint) < 0) {
 850                 close(cmd->out);
 851                 finish_command(cmd); /* throw away exit code */
 852                 return -1;
 853         }
 854
 855         close(cmd->out);
 856         return finish_command(cmd);
 857 }