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 struct child_to_clean {
  15         pid_t pid;
  16         struct child_to_clean *next;
  17 };
  18 static struct child_to_clean *children_to_clean;
  19 static int installed_child_cleanup_handler;
  20
  21 static void cleanup_children(int sig)
  22 {
  23         while (children_to_clean) {
  24                 struct child_to_clean *p = children_to_clean;
  25                 children_to_clean = p->next;
  26                 kill(p->pid, sig);
  27                 free(p);
  28         }
  29 }
  30
  31 static void cleanup_children_on_signal(int sig)
  32 {
  33         cleanup_children(sig);
  34         sigchain_pop(sig);
  35         raise(sig);
  36 }
  37
  38 static void cleanup_children_on_exit(void)
  39 {
  40         cleanup_children(SIGTERM);
  41 }
  42
  43 static void mark_child_for_cleanup(pid_t pid)
  44 {
  45         struct child_to_clean *p = xmalloc(sizeof(*p));
  46         p->pid = pid;
  47         p->next = children_to_clean;
  48         children_to_clean = p;
  49
  50         if (!installed_child_cleanup_handler) {
  51                 atexit(cleanup_children_on_exit);
  52                 sigchain_push_common(cleanup_children_on_signal);
  53                 installed_child_cleanup_handler = 1;
  54         }
  55 }
  56
  57 static void clear_child_for_cleanup(pid_t pid)
  58 {
  59         struct child_to_clean **pp;
  60
  61         for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
  62                 struct child_to_clean *clean_me = *pp;
  63
  64                 if (clean_me->pid == pid) {
  65                         *pp = clean_me->next;
  66                         free(clean_me);
  67                         return;
  68                 }
  69         }
  70 }
  71
  72 static inline void close_pair(int fd[2])
  73 {
  74         close(fd[0]);
  75         close(fd[1]);
  76 }
  77
  78 #ifndef GIT_WINDOWS_NATIVE
  79 static inline void dup_devnull(int to)
  80 {
  81         int fd = open("/dev/null", O_RDWR);
  82         if (fd < 0)
  83                 die_errno(_("open /dev/null failed"));
  84         if (dup2(fd, to) < 0)
  85                 die_errno(_("dup2(%d,%d) failed"), fd, to);
  86         close(fd);
  87 }
  88 #endif
  89
  90 static char *locate_in_PATH(const char *file)
  91 {
  92         const char *p = getenv("PATH");
  93         struct strbuf buf = STRBUF_INIT;
  94
  95         if (!p || !*p)
  96                 return NULL;
  97
  98         while (1) {
  99                 const char *end = strchrnul(p, ':');
 100
 101                 strbuf_reset(&buf);
 102
 103                 /* POSIX specifies an empty entry as the current directory. */
 104                 if (end != p) {
 105                         strbuf_add(&buf, p, end - p);
 106                         strbuf_addch(&buf, '/');
 107                 }
 108                 strbuf_addstr(&buf, file);
 109
 110                 if (!access(buf.buf, F_OK))
 111                         return strbuf_detach(&buf, NULL);
 112
 113                 if (!*end)
 114                         break;
 115                 p = end + 1;
 116         }
 117
 118         strbuf_release(&buf);
 119         return NULL;
 120 }
 121
 122 static int exists_in_PATH(const char *file)
 123 {
 124         char *r = locate_in_PATH(file);
 125         free(r);
 126         return r != NULL;
 127 }
 128
 129 int sane_execvp(const char *file, char * const argv[])
 130 {
 131         if (!execvp(file, argv))
 132                 return 0; /* cannot happen ;-) */
 133
 134         /*
 135          * When a command can't be found because one of the directories
 136          * listed in $PATH is unsearchable, execvp reports EACCES, but
 137          * careful usability testing (read: analysis of occasional bug
 138          * reports) reveals that "No such file or directory" is more
 139          * intuitive.
 140          *
 141          * We avoid commands with "/", because execvp will not do $PATH
 142          * lookups in that case.
 143          *
 144          * The reassignment of EACCES to errno looks like a no-op below,
 145          * but we need to protect against exists_in_PATH overwriting errno.
 146          */
 147         if (errno == EACCES && !strchr(file, '/'))
 148                 errno = exists_in_PATH(file) ? EACCES : ENOENT;
 149         else if (errno == ENOTDIR && !strchr(file, '/'))
 150                 errno = ENOENT;
 151         return -1;
 152 }
 153
 154 static const char **prepare_shell_cmd(const char **argv)
 155 {
 156         int argc, nargc = 0;
 157         const char **nargv;
 158
 159         for (argc = 0; argv[argc]; argc++)
 160                 ; /* just counting */
 161         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
 162         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
 163
 164         if (argc < 1)
 165                 die("BUG: shell command is empty");
 166
 167         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 168 #ifndef GIT_WINDOWS_NATIVE
 169                 nargv[nargc++] = SHELL_PATH;
 170 #else
 171                 nargv[nargc++] = "sh";
 172 #endif
 173                 nargv[nargc++] = "-c";
 174
 175                 if (argc < 2)
 176                         nargv[nargc++] = argv[0];
 177                 else {
 178                         struct strbuf arg0 = STRBUF_INIT;
 179                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 180                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
 181                 }
 182         }
 183
 184         for (argc = 0; argv[argc]; argc++)
 185                 nargv[nargc++] = argv[argc];
 186         nargv[nargc] = NULL;
 187
 188         return nargv;
 189 }
 190
 191 #ifndef GIT_WINDOWS_NATIVE
 192 static int execv_shell_cmd(const char **argv)
 193 {
 194         const char **nargv = prepare_shell_cmd(argv);
 195         trace_argv_printf(nargv, "trace: exec:");
 196         sane_execvp(nargv[0], (char **)nargv);
 197         free(nargv);
 198         return -1;
 199 }
 200 #endif
 201
 202 #ifndef GIT_WINDOWS_NATIVE
 203 static int child_err = 2;
 204 static int child_notifier = -1;
 205
 206 static void notify_parent(void)
 207 {
 208         /*
 209          * execvp failed.  If possible, we'd like to let start_command
 210          * know, so failures like ENOENT can be handled right away; but
 211          * otherwise, finish_command will still report the error.
 212          */
 213         xwrite(child_notifier, "", 1);
 214 }
 215
 216 static NORETURN void die_child(const char *err, va_list params)
 217 {
 218         vwritef(child_err, "fatal: ", err, params);
 219         exit(128);
 220 }
 221
 222 static void error_child(const char *err, va_list params)
 223 {
 224         vwritef(child_err, "error: ", err, params);
 225 }
 226 #endif
 227
 228 static inline void set_cloexec(int fd)
 229 {
 230         int flags = fcntl(fd, F_GETFD);
 231         if (flags >= 0)
 232                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 233 }
 234
 235 static int wait_or_whine(pid_t pid, const char *argv0)
 236 {
 237         int status, code = -1;
 238         pid_t waiting;
 239         int failed_errno = 0;
 240
 241         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 242                 ;       /* nothing */
 243
 244         if (waiting < 0) {
 245                 failed_errno = errno;
 246                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 247         } else if (waiting != pid) {
 248                 error("waitpid is confused (%s)", argv0);
 249         } else if (WIFSIGNALED(status)) {
 250                 code = WTERMSIG(status);
 251                 if (code != SIGINT && code != SIGQUIT)
 252                         error("%s died of signal %d", argv0, code);
 253                 /*
 254                  * This return value is chosen so that code & 0xff
 255                  * mimics the exit code that a POSIX shell would report for
 256                  * a program that died from this signal.
 257                  */
 258                 code += 128;
 259         } else if (WIFEXITED(status)) {
 260                 code = WEXITSTATUS(status);
 261                 /*
 262                  * Convert special exit code when execvp failed.
 263                  */
 264                 if (code == 127) {
 265                         code = -1;
 266                         failed_errno = ENOENT;
 267                 }
 268         } else {
 269                 error("waitpid is confused (%s)", argv0);
 270         }
 271
 272         clear_child_for_cleanup(pid);
 273
 274         errno = failed_errno;
 275         return code;
 276 }
 277
 278 int start_command(struct child_process *cmd)
 279 {
 280         int need_in, need_out, need_err;
 281         int fdin[2], fdout[2], fderr[2];
 282         int failed_errno;
 283         char *str;
 284
 285         if (!cmd->argv)
 286                 cmd->argv = cmd->args.argv;
 287         if (!cmd->env)
 288                 cmd->env = cmd->env_array.argv;
 289
 290         /*
 291          * In case of errors we must keep the promise to close FDs
 292          * that have been passed in via ->in and ->out.
 293          */
 294
 295         need_in = !cmd->no_stdin && cmd->in < 0;
 296         if (need_in) {
 297                 if (pipe(fdin) < 0) {
 298                         failed_errno = errno;
 299                         if (cmd->out > 0)
 300                                 close(cmd->out);
 301                         str = "standard input";
 302                         goto fail_pipe;
 303                 }
 304                 cmd->in = fdin[1];
 305         }
 306
 307         need_out = !cmd->no_stdout
 308                 && !cmd->stdout_to_stderr
 309                 && cmd->out < 0;
 310         if (need_out) {
 311                 if (pipe(fdout) < 0) {
 312                         failed_errno = errno;
 313                         if (need_in)
 314                                 close_pair(fdin);
 315                         else if (cmd->in)
 316                                 close(cmd->in);
 317                         str = "standard output";
 318                         goto fail_pipe;
 319                 }
 320                 cmd->out = fdout[0];
 321         }
 322
 323         need_err = !cmd->no_stderr && cmd->err < 0;
 324         if (need_err) {
 325                 if (pipe(fderr) < 0) {
 326                         failed_errno = errno;
 327                         if (need_in)
 328                                 close_pair(fdin);
 329                         else if (cmd->in)
 330                                 close(cmd->in);
 331                         if (need_out)
 332                                 close_pair(fdout);
 333                         else if (cmd->out)
 334                                 close(cmd->out);
 335                         str = "standard error";
 336 fail_pipe:
 337                         error("cannot create %s pipe for %s: %s",
 338                                 str, cmd->argv[0], strerror(failed_errno));
 339                         argv_array_clear(&cmd->args);
 340                         argv_array_clear(&cmd->env_array);
 341                         errno = failed_errno;
 342                         return -1;
 343                 }
 344                 cmd->err = fderr[0];
 345         }
 346
 347         trace_argv_printf(cmd->argv, "trace: run_command:");
 348         fflush(NULL);
 349
 350 #ifndef GIT_WINDOWS_NATIVE
 351 {
 352         int notify_pipe[2];
 353         if (pipe(notify_pipe))
 354                 notify_pipe[0] = notify_pipe[1] = -1;
 355
 356         cmd->pid = fork();
 357         failed_errno = errno;
 358         if (!cmd->pid) {
 359                 /*
 360                  * Redirect the channel to write syscall error messages to
 361                  * before redirecting the process's stderr so that all die()
 362                  * in subsequent call paths use the parent's stderr.
 363                  */
 364                 if (cmd->no_stderr || need_err) {
 365                         child_err = dup(2);
 366                         set_cloexec(child_err);
 367                 }
 368                 set_die_routine(die_child);
 369                 set_error_routine(error_child);
 370
 371                 close(notify_pipe[0]);
 372                 set_cloexec(notify_pipe[1]);
 373                 child_notifier = notify_pipe[1];
 374                 atexit(notify_parent);
 375
 376                 if (cmd->no_stdin)
 377                         dup_devnull(0);
 378                 else if (need_in) {
 379                         dup2(fdin[0], 0);
 380                         close_pair(fdin);
 381                 } else if (cmd->in) {
 382                         dup2(cmd->in, 0);
 383                         close(cmd->in);
 384                 }
 385
 386                 if (cmd->no_stderr)
 387                         dup_devnull(2);
 388                 else if (need_err) {
 389                         dup2(fderr[1], 2);
 390                         close_pair(fderr);
 391                 } else if (cmd->err > 1) {
 392                         dup2(cmd->err, 2);
 393                         close(cmd->err);
 394                 }
 395
 396                 if (cmd->no_stdout)
 397                         dup_devnull(1);
 398                 else if (cmd->stdout_to_stderr)
 399                         dup2(2, 1);
 400                 else if (need_out) {
 401                         dup2(fdout[1], 1);
 402                         close_pair(fdout);
 403                 } else if (cmd->out > 1) {
 404                         dup2(cmd->out, 1);
 405                         close(cmd->out);
 406                 }
 407
 408                 if (cmd->dir && chdir(cmd->dir))
 409                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 410                             cmd->dir);
 411                 if (cmd->env) {
 412                         for (; *cmd->env; cmd->env++) {
 413                                 if (strchr(*cmd->env, '='))
 414                                         putenv((char *)*cmd->env);
 415                                 else
 416                                         unsetenv(*cmd->env);
 417                         }
 418                 }
 419                 if (cmd->git_cmd)
 420                         execv_git_cmd(cmd->argv);
 421                 else if (cmd->use_shell)
 422                         execv_shell_cmd(cmd->argv);
 423                 else
 424                         sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 425                 if (errno == ENOENT) {
 426                         if (!cmd->silent_exec_failure)
 427                                 error("cannot run %s: %s", cmd->argv[0],
 428                                         strerror(ENOENT));
 429                         exit(127);
 430                 } else {
 431                         die_errno("cannot exec '%s'", cmd->argv[0]);
 432                 }
 433         }
 434         if (cmd->pid < 0)
 435                 error("cannot fork() for %s: %s", cmd->argv[0],
 436                         strerror(errno));
 437         else if (cmd->clean_on_exit)
 438                 mark_child_for_cleanup(cmd->pid);
 439
 440         /*
 441          * Wait for child's execvp. If the execvp succeeds (or if fork()
 442          * failed), EOF is seen immediately by the parent. Otherwise, the
 443          * child process sends a single byte.
 444          * Note that use of this infrastructure is completely advisory,
 445          * therefore, we keep error checks minimal.
 446          */
 447         close(notify_pipe[1]);
 448         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 449                 /*
 450                  * At this point we know that fork() succeeded, but execvp()
 451                  * failed. Errors have been reported to our stderr.
 452                  */
 453                 wait_or_whine(cmd->pid, cmd->argv[0]);
 454                 failed_errno = errno;
 455                 cmd->pid = -1;
 456         }
 457         close(notify_pipe[0]);
 458 }
 459 #else
 460 {
 461         int fhin = 0, fhout = 1, fherr = 2;
 462         const char **sargv = cmd->argv;
 463
 464         if (cmd->no_stdin)
 465                 fhin = open("/dev/null", O_RDWR);
 466         else if (need_in)
 467                 fhin = dup(fdin[0]);
 468         else if (cmd->in)
 469                 fhin = dup(cmd->in);
 470
 471         if (cmd->no_stderr)
 472                 fherr = open("/dev/null", O_RDWR);
 473         else if (need_err)
 474                 fherr = dup(fderr[1]);
 475         else if (cmd->err > 2)
 476                 fherr = dup(cmd->err);
 477
 478         if (cmd->no_stdout)
 479                 fhout = open("/dev/null", O_RDWR);
 480         else if (cmd->stdout_to_stderr)
 481                 fhout = dup(fherr);
 482         else if (need_out)
 483                 fhout = dup(fdout[1]);
 484         else if (cmd->out > 1)
 485                 fhout = dup(cmd->out);
 486
 487         if (cmd->git_cmd)
 488                 cmd->argv = prepare_git_cmd(cmd->argv);
 489         else if (cmd->use_shell)
 490                 cmd->argv = prepare_shell_cmd(cmd->argv);
 491
 492         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
 493                         cmd->dir, fhin, fhout, fherr);
 494         failed_errno = errno;
 495         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 496                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 497         if (cmd->clean_on_exit && cmd->pid >= 0)
 498                 mark_child_for_cleanup(cmd->pid);
 499
 500         if (cmd->git_cmd)
 501                 free(cmd->argv);
 502
 503         cmd->argv = sargv;
 504         if (fhin != 0)
 505                 close(fhin);
 506         if (fhout != 1)
 507                 close(fhout);
 508         if (fherr != 2)
 509                 close(fherr);
 510 }
 511 #endif
 512
 513         if (cmd->pid < 0) {
 514                 if (need_in)
 515                         close_pair(fdin);
 516                 else if (cmd->in)
 517                         close(cmd->in);
 518                 if (need_out)
 519                         close_pair(fdout);
 520                 else if (cmd->out)
 521                         close(cmd->out);
 522                 if (need_err)
 523                         close_pair(fderr);
 524                 else if (cmd->err)
 525                         close(cmd->err);
 526                 argv_array_clear(&cmd->args);
 527                 argv_array_clear(&cmd->env_array);
 528                 errno = failed_errno;
 529                 return -1;
 530         }
 531
 532         if (need_in)
 533                 close(fdin[0]);
 534         else if (cmd->in)
 535                 close(cmd->in);
 536
 537         if (need_out)
 538                 close(fdout[1]);
 539         else if (cmd->out)
 540                 close(cmd->out);
 541
 542         if (need_err)
 543                 close(fderr[1]);
 544         else if (cmd->err)
 545                 close(cmd->err);
 546
 547         return 0;
 548 }
 549
 550 int finish_command(struct child_process *cmd)
 551 {
 552         int ret = wait_or_whine(cmd->pid, cmd->argv[0]);
 553         argv_array_clear(&cmd->args);
 554         argv_array_clear(&cmd->env_array);
 555         return ret;
 556 }
 557
 558 int run_command(struct child_process *cmd)
 559 {
 560         int code;
 561
 562         if (cmd->out < 0 || cmd->err < 0)
 563                 die("BUG: run_command with a pipe can cause deadlock");
 564
 565         code = start_command(cmd);
 566         if (code)
 567                 return code;
 568         return finish_command(cmd);
 569 }
 570
 571 int run_command_v_opt(const char **argv, int opt)
 572 {
 573         return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
 574 }
 575
 576 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 577 {
 578         struct child_process cmd = CHILD_PROCESS_INIT;
 579         cmd.argv = argv;
 580         cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 581         cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 582         cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 583         cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 584         cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 585         cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 586         cmd.dir = dir;
 587         cmd.env = env;
 588         return run_command(&cmd);
 589 }
 590
 591 #ifndef NO_PTHREADS
 592 static pthread_t main_thread;
 593 static int main_thread_set;
 594 static pthread_key_t async_key;
 595 static pthread_key_t async_die_counter;
 596
 597 static void *run_thread(void *data)
 598 {
 599         struct async *async = data;
 600         intptr_t ret;
 601
 602         pthread_setspecific(async_key, async);
 603         ret = async->proc(async->proc_in, async->proc_out, async->data);
 604         return (void *)ret;
 605 }
 606
 607 static NORETURN void die_async(const char *err, va_list params)
 608 {
 609         vreportf("fatal: ", err, params);
 610
 611         if (!pthread_equal(main_thread, pthread_self())) {
 612                 struct async *async = pthread_getspecific(async_key);
 613                 if (async->proc_in >= 0)
 614                         close(async->proc_in);
 615                 if (async->proc_out >= 0)
 616                         close(async->proc_out);
 617                 pthread_exit((void *)128);
 618         }
 619
 620         exit(128);
 621 }
 622
 623 static int async_die_is_recursing(void)
 624 {
 625         void *ret = pthread_getspecific(async_die_counter);
 626         pthread_setspecific(async_die_counter, (void *)1);
 627         return ret != NULL;
 628 }
 629
 630 #else
 631
 632 static struct {
 633         void (**handlers)(void);
 634         size_t nr;
 635         size_t alloc;
 636 } git_atexit_hdlrs;
 637
 638 static int git_atexit_installed;
 639
 640 static void git_atexit_dispatch(void)
 641 {
 642         size_t i;
 643
 644         for (i=git_atexit_hdlrs.nr ; i ; i--)
 645                 git_atexit_hdlrs.handlers[i-1]();
 646 }
 647
 648 static void git_atexit_clear(void)
 649 {
 650         free(git_atexit_hdlrs.handlers);
 651         memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
 652         git_atexit_installed = 0;
 653 }
 654
 655 #undef atexit
 656 int git_atexit(void (*handler)(void))
 657 {
 658         ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
 659         git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
 660         if (!git_atexit_installed) {
 661                 if (atexit(&git_atexit_dispatch))
 662                         return -1;
 663                 git_atexit_installed = 1;
 664         }
 665         return 0;
 666 }
 667 #define atexit git_atexit
 668
 669 #endif
 670
 671 int start_async(struct async *async)
 672 {
 673         int need_in, need_out;
 674         int fdin[2], fdout[2];
 675         int proc_in, proc_out;
 676
 677         need_in = async->in < 0;
 678         if (need_in) {
 679                 if (pipe(fdin) < 0) {
 680                         if (async->out > 0)
 681                                 close(async->out);
 682                         return error("cannot create pipe: %s", strerror(errno));
 683                 }
 684                 async->in = fdin[1];
 685         }
 686
 687         need_out = async->out < 0;
 688         if (need_out) {
 689                 if (pipe(fdout) < 0) {
 690                         if (need_in)
 691                                 close_pair(fdin);
 692                         else if (async->in)
 693                                 close(async->in);
 694                         return error("cannot create pipe: %s", strerror(errno));
 695                 }
 696                 async->out = fdout[0];
 697         }
 698
 699         if (need_in)
 700                 proc_in = fdin[0];
 701         else if (async->in)
 702                 proc_in = async->in;
 703         else
 704                 proc_in = -1;
 705
 706         if (need_out)
 707                 proc_out = fdout[1];
 708         else if (async->out)
 709                 proc_out = async->out;
 710         else
 711                 proc_out = -1;
 712
 713 #ifdef NO_PTHREADS
 714         /* Flush stdio before fork() to avoid cloning buffers */
 715         fflush(NULL);
 716
 717         async->pid = fork();
 718         if (async->pid < 0) {
 719                 error("fork (async) failed: %s", strerror(errno));
 720                 goto error;
 721         }
 722         if (!async->pid) {
 723                 if (need_in)
 724                         close(fdin[1]);
 725                 if (need_out)
 726                         close(fdout[0]);
 727                 git_atexit_clear();
 728                 exit(!!async->proc(proc_in, proc_out, async->data));
 729         }
 730
 731         mark_child_for_cleanup(async->pid);
 732
 733         if (need_in)
 734                 close(fdin[0]);
 735         else if (async->in)
 736                 close(async->in);
 737
 738         if (need_out)
 739                 close(fdout[1]);
 740         else if (async->out)
 741                 close(async->out);
 742 #else
 743         if (!main_thread_set) {
 744                 /*
 745                  * We assume that the first time that start_async is called
 746                  * it is from the main thread.
 747                  */
 748                 main_thread_set = 1;
 749                 main_thread = pthread_self();
 750                 pthread_key_create(&async_key, NULL);
 751                 pthread_key_create(&async_die_counter, NULL);
 752                 set_die_routine(die_async);
 753                 set_die_is_recursing_routine(async_die_is_recursing);
 754         }
 755
 756         if (proc_in >= 0)
 757                 set_cloexec(proc_in);
 758         if (proc_out >= 0)
 759                 set_cloexec(proc_out);
 760         async->proc_in = proc_in;
 761         async->proc_out = proc_out;
 762         {
 763                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 764                 if (err) {
 765                         error("cannot create thread: %s", strerror(err));
 766                         goto error;
 767                 }
 768         }
 769 #endif
 770         return 0;
 771
 772 error:
 773         if (need_in)
 774                 close_pair(fdin);
 775         else if (async->in)
 776                 close(async->in);
 777
 778         if (need_out)
 779                 close_pair(fdout);
 780         else if (async->out)
 781                 close(async->out);
 782         return -1;
 783 }
 784
 785 int finish_async(struct async *async)
 786 {
 787 #ifdef NO_PTHREADS
 788         return wait_or_whine(async->pid, "child process");
 789 #else
 790         void *ret = (void *)(intptr_t)(-1);
 791
 792         if (pthread_join(async->tid, &ret))
 793                 error("pthread_join failed");
 794         return (int)(intptr_t)ret;
 795 #endif
 796 }
 797
 798 char *find_hook(const char *name)
 799 {
 800         char *path = git_path("hooks/%s", name);
 801         if (access(path, X_OK) < 0)
 802                 path = NULL;
 803
 804         return path;
 805 }
 806
 807 int run_hook_ve(const char *const *env, const char *name, va_list args)
 808 {
 809         struct child_process hook = CHILD_PROCESS_INIT;
 810         const char *p;
 811
 812         p = find_hook(name);
 813         if (!p)
 814                 return 0;
 815
 816         argv_array_push(&hook.args, p);
 817         while ((p = va_arg(args, const char *)))
 818                 argv_array_push(&hook.args, p);
 819         hook.env = env;
 820         hook.no_stdin = 1;
 821         hook.stdout_to_stderr = 1;
 822
 823         return run_command(&hook);
 824 }
 825
 826 int run_hook_le(const char *const *env, const char *name, ...)
 827 {
 828         va_list args;
 829         int ret;
 830
 831         va_start(args, name);
 832         ret = run_hook_ve(env, name, args);
 833         va_end(args);
 834
 835         return ret;
 836 }
 837
 838 int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint)
 839 {
 840         cmd->out = -1;
 841         if (start_command(cmd) < 0)
 842                 return -1;
 843
 844         if (strbuf_read(buf, cmd->out, hint) < 0) {
 845                 close(cmd->out);
 846                 finish_command(cmd); /* throw away exit code */
 847                 return -1;
 848         }
 849
 850         close(cmd->out);
 851         return finish_command(cmd);
 852 }