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 void child_process_init(struct child_process *child)
  12 {
  13         memset(child, 0, sizeof(*child));
  14         argv_array_init(&child->args);
  15         argv_array_init(&child->env_array);
  16 }
  17
  18 struct child_to_clean {
  19         pid_t pid;
  20         struct child_to_clean *next;
  21 };
  22 static struct child_to_clean *children_to_clean;
  23 static int installed_child_cleanup_handler;
  24
  25 static void cleanup_children(int sig)
  26 {
  27         while (children_to_clean) {
  28                 struct child_to_clean *p = children_to_clean;
  29                 children_to_clean = p->next;
  30                 kill(p->pid, sig);
  31                 free(p);
  32         }
  33 }
  34
  35 static void cleanup_children_on_signal(int sig)
  36 {
  37         cleanup_children(sig);
  38         sigchain_pop(sig);
  39         raise(sig);
  40 }
  41
  42 static void cleanup_children_on_exit(void)
  43 {
  44         cleanup_children(SIGTERM);
  45 }
  46
  47 static void mark_child_for_cleanup(pid_t pid)
  48 {
  49         struct child_to_clean *p = xmalloc(sizeof(*p));
  50         p->pid = pid;
  51         p->next = children_to_clean;
  52         children_to_clean = p;
  53
  54         if (!installed_child_cleanup_handler) {
  55                 atexit(cleanup_children_on_exit);
  56                 sigchain_push_common(cleanup_children_on_signal);
  57                 installed_child_cleanup_handler = 1;
  58         }
  59 }
  60
  61 static void clear_child_for_cleanup(pid_t pid)
  62 {
  63         struct child_to_clean **pp;
  64
  65         for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
  66                 struct child_to_clean *clean_me = *pp;
  67
  68                 if (clean_me->pid == pid) {
  69                         *pp = clean_me->next;
  70                         free(clean_me);
  71                         return;
  72                 }
  73         }
  74 }
  75
  76 static inline void close_pair(int fd[2])
  77 {
  78         close(fd[0]);
  79         close(fd[1]);
  80 }
  81
  82 #ifndef GIT_WINDOWS_NATIVE
  83 static inline void dup_devnull(int to)
  84 {
  85         int fd = open("/dev/null", O_RDWR);
  86         if (fd < 0)
  87                 die_errno(_("open /dev/null failed"));
  88         if (dup2(fd, to) < 0)
  89                 die_errno(_("dup2(%d,%d) failed"), fd, to);
  90         close(fd);
  91 }
  92 #endif
  93
  94 static char *locate_in_PATH(const char *file)
  95 {
  96         const char *p = getenv("PATH");
  97         struct strbuf buf = STRBUF_INIT;
  98
  99         if (!p || !*p)
 100                 return NULL;
 101
 102         while (1) {
 103                 const char *end = strchrnul(p, ':');
 104
 105                 strbuf_reset(&buf);
 106
 107                 /* POSIX specifies an empty entry as the current directory. */
 108                 if (end != p) {
 109                         strbuf_add(&buf, p, end - p);
 110                         strbuf_addch(&buf, '/');
 111                 }
 112                 strbuf_addstr(&buf, file);
 113
 114                 if (!access(buf.buf, F_OK))
 115                         return strbuf_detach(&buf, NULL);
 116
 117                 if (!*end)
 118                         break;
 119                 p = end + 1;
 120         }
 121
 122         strbuf_release(&buf);
 123         return NULL;
 124 }
 125
 126 static int exists_in_PATH(const char *file)
 127 {
 128         char *r = locate_in_PATH(file);
 129         free(r);
 130         return r != NULL;
 131 }
 132
 133 int sane_execvp(const char *file, char * const argv[])
 134 {
 135         if (!execvp(file, argv))
 136                 return 0; /* cannot happen ;-) */
 137
 138         /*
 139          * When a command can't be found because one of the directories
 140          * listed in $PATH is unsearchable, execvp reports EACCES, but
 141          * careful usability testing (read: analysis of occasional bug
 142          * reports) reveals that "No such file or directory" is more
 143          * intuitive.
 144          *
 145          * We avoid commands with "/", because execvp will not do $PATH
 146          * lookups in that case.
 147          *
 148          * The reassignment of EACCES to errno looks like a no-op below,
 149          * but we need to protect against exists_in_PATH overwriting errno.
 150          */
 151         if (errno == EACCES && !strchr(file, '/'))
 152                 errno = exists_in_PATH(file) ? EACCES : ENOENT;
 153         else if (errno == ENOTDIR && !strchr(file, '/'))
 154                 errno = ENOENT;
 155         return -1;
 156 }
 157
 158 static const char **prepare_shell_cmd(const char **argv)
 159 {
 160         int argc, nargc = 0;
 161         const char **nargv;
 162
 163         for (argc = 0; argv[argc]; argc++)
 164                 ; /* just counting */
 165         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
 166         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
 167
 168         if (argc < 1)
 169                 die("BUG: shell command is empty");
 170
 171         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 172 #ifndef GIT_WINDOWS_NATIVE
 173                 nargv[nargc++] = SHELL_PATH;
 174 #else
 175                 nargv[nargc++] = "sh";
 176 #endif
 177                 nargv[nargc++] = "-c";
 178
 179                 if (argc < 2)
 180                         nargv[nargc++] = argv[0];
 181                 else {
 182                         struct strbuf arg0 = STRBUF_INIT;
 183                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 184                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
 185                 }
 186         }
 187
 188         for (argc = 0; argv[argc]; argc++)
 189                 nargv[nargc++] = argv[argc];
 190         nargv[nargc] = NULL;
 191
 192         return nargv;
 193 }
 194
 195 #ifndef GIT_WINDOWS_NATIVE
 196 static int execv_shell_cmd(const char **argv)
 197 {
 198         const char **nargv = prepare_shell_cmd(argv);
 199         trace_argv_printf(nargv, "trace: exec:");
 200         sane_execvp(nargv[0], (char **)nargv);
 201         free(nargv);
 202         return -1;
 203 }
 204 #endif
 205
 206 #ifndef GIT_WINDOWS_NATIVE
 207 static int child_err = 2;
 208 static int child_notifier = -1;
 209
 210 static void notify_parent(void)
 211 {
 212         /*
 213          * execvp failed.  If possible, we'd like to let start_command
 214          * know, so failures like ENOENT can be handled right away; but
 215          * otherwise, finish_command will still report the error.
 216          */
 217         xwrite(child_notifier, "", 1);
 218 }
 219
 220 static NORETURN void die_child(const char *err, va_list params)
 221 {
 222         vwritef(child_err, "fatal: ", err, params);
 223         exit(128);
 224 }
 225
 226 static void error_child(const char *err, va_list params)
 227 {
 228         vwritef(child_err, "error: ", err, params);
 229 }
 230 #endif
 231
 232 static inline void set_cloexec(int fd)
 233 {
 234         int flags = fcntl(fd, F_GETFD);
 235         if (flags >= 0)
 236                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 237 }
 238
 239 static int wait_or_whine(pid_t pid, const char *argv0)
 240 {
 241         int status, code = -1;
 242         pid_t waiting;
 243         int failed_errno = 0;
 244
 245         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 246                 ;       /* nothing */
 247
 248         if (waiting < 0) {
 249                 failed_errno = errno;
 250                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 251         } else if (waiting != pid) {
 252                 error("waitpid is confused (%s)", argv0);
 253         } else if (WIFSIGNALED(status)) {
 254                 code = WTERMSIG(status);
 255                 if (code != SIGINT && code != SIGQUIT)
 256                         error("%s died of signal %d", argv0, code);
 257                 /*
 258                  * This return value is chosen so that code & 0xff
 259                  * mimics the exit code that a POSIX shell would report for
 260                  * a program that died from this signal.
 261                  */
 262                 code += 128;
 263         } else if (WIFEXITED(status)) {
 264                 code = WEXITSTATUS(status);
 265                 /*
 266                  * Convert special exit code when execvp failed.
 267                  */
 268                 if (code == 127) {
 269                         code = -1;
 270                         failed_errno = ENOENT;
 271                 }
 272         } else {
 273                 error("waitpid is confused (%s)", argv0);
 274         }
 275
 276         clear_child_for_cleanup(pid);
 277
 278         errno = failed_errno;
 279         return code;
 280 }
 281
 282 int start_command(struct child_process *cmd)
 283 {
 284         int need_in, need_out, need_err;
 285         int fdin[2], fdout[2], fderr[2];
 286         int failed_errno;
 287         char *str;
 288
 289         if (!cmd->argv)
 290                 cmd->argv = cmd->args.argv;
 291         if (!cmd->env)
 292                 cmd->env = cmd->env_array.argv;
 293
 294         /*
 295          * In case of errors we must keep the promise to close FDs
 296          * that have been passed in via ->in and ->out.
 297          */
 298
 299         need_in = !cmd->no_stdin && cmd->in < 0;
 300         if (need_in) {
 301                 if (pipe(fdin) < 0) {
 302                         failed_errno = errno;
 303                         if (cmd->out > 0)
 304                                 close(cmd->out);
 305                         str = "standard input";
 306                         goto fail_pipe;
 307                 }
 308                 cmd->in = fdin[1];
 309         }
 310
 311         need_out = !cmd->no_stdout
 312                 && !cmd->stdout_to_stderr
 313                 && cmd->out < 0;
 314         if (need_out) {
 315                 if (pipe(fdout) < 0) {
 316                         failed_errno = errno;
 317                         if (need_in)
 318                                 close_pair(fdin);
 319                         else if (cmd->in)
 320                                 close(cmd->in);
 321                         str = "standard output";
 322                         goto fail_pipe;
 323                 }
 324                 cmd->out = fdout[0];
 325         }
 326
 327         need_err = !cmd->no_stderr && cmd->err < 0;
 328         if (need_err) {
 329                 if (pipe(fderr) < 0) {
 330                         failed_errno = errno;
 331                         if (need_in)
 332                                 close_pair(fdin);
 333                         else if (cmd->in)
 334                                 close(cmd->in);
 335                         if (need_out)
 336                                 close_pair(fdout);
 337                         else if (cmd->out)
 338                                 close(cmd->out);
 339                         str = "standard error";
 340 fail_pipe:
 341                         error("cannot create %s pipe for %s: %s",
 342                                 str, cmd->argv[0], strerror(failed_errno));
 343                         argv_array_clear(&cmd->args);
 344                         argv_array_clear(&cmd->env_array);
 345                         errno = failed_errno;
 346                         return -1;
 347                 }
 348                 cmd->err = fderr[0];
 349         }
 350
 351         trace_argv_printf(cmd->argv, "trace: run_command:");
 352         fflush(NULL);
 353
 354 #ifndef GIT_WINDOWS_NATIVE
 355 {
 356         int notify_pipe[2];
 357         if (pipe(notify_pipe))
 358                 notify_pipe[0] = notify_pipe[1] = -1;
 359
 360         cmd->pid = fork();
 361         failed_errno = errno;
 362         if (!cmd->pid) {
 363                 /*
 364                  * Redirect the channel to write syscall error messages to
 365                  * before redirecting the process's stderr so that all die()
 366                  * in subsequent call paths use the parent's stderr.
 367                  */
 368                 if (cmd->no_stderr || need_err) {
 369                         child_err = dup(2);
 370                         set_cloexec(child_err);
 371                 }
 372                 set_die_routine(die_child);
 373                 set_error_routine(error_child);
 374
 375                 close(notify_pipe[0]);
 376                 set_cloexec(notify_pipe[1]);
 377                 child_notifier = notify_pipe[1];
 378                 atexit(notify_parent);
 379
 380                 if (cmd->no_stdin)
 381                         dup_devnull(0);
 382                 else if (need_in) {
 383                         dup2(fdin[0], 0);
 384                         close_pair(fdin);
 385                 } else if (cmd->in) {
 386                         dup2(cmd->in, 0);
 387                         close(cmd->in);
 388                 }
 389
 390                 if (cmd->no_stderr)
 391                         dup_devnull(2);
 392                 else if (need_err) {
 393                         dup2(fderr[1], 2);
 394                         close_pair(fderr);
 395                 } else if (cmd->err > 1) {
 396                         dup2(cmd->err, 2);
 397                         close(cmd->err);
 398                 }
 399
 400                 if (cmd->no_stdout)
 401                         dup_devnull(1);
 402                 else if (cmd->stdout_to_stderr)
 403                         dup2(2, 1);
 404                 else if (need_out) {
 405                         dup2(fdout[1], 1);
 406                         close_pair(fdout);
 407                 } else if (cmd->out > 1) {
 408                         dup2(cmd->out, 1);
 409                         close(cmd->out);
 410                 }
 411
 412                 if (cmd->dir && chdir(cmd->dir))
 413                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 414                             cmd->dir);
 415                 if (cmd->env) {
 416                         for (; *cmd->env; cmd->env++) {
 417                                 if (strchr(*cmd->env, '='))
 418                                         putenv((char *)*cmd->env);
 419                                 else
 420                                         unsetenv(*cmd->env);
 421                         }
 422                 }
 423                 if (cmd->git_cmd)
 424                         execv_git_cmd(cmd->argv);
 425                 else if (cmd->use_shell)
 426                         execv_shell_cmd(cmd->argv);
 427                 else
 428                         sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 429                 if (errno == ENOENT) {
 430                         if (!cmd->silent_exec_failure)
 431                                 error("cannot run %s: %s", cmd->argv[0],
 432                                         strerror(ENOENT));
 433                         exit(127);
 434                 } else {
 435                         die_errno("cannot exec '%s'", cmd->argv[0]);
 436                 }
 437         }
 438         if (cmd->pid < 0)
 439                 error("cannot fork() for %s: %s", cmd->argv[0],
 440                         strerror(errno));
 441         else if (cmd->clean_on_exit)
 442                 mark_child_for_cleanup(cmd->pid);
 443
 444         /*
 445          * Wait for child's execvp. If the execvp succeeds (or if fork()
 446          * failed), EOF is seen immediately by the parent. Otherwise, the
 447          * child process sends a single byte.
 448          * Note that use of this infrastructure is completely advisory,
 449          * therefore, we keep error checks minimal.
 450          */
 451         close(notify_pipe[1]);
 452         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 453                 /*
 454                  * At this point we know that fork() succeeded, but execvp()
 455                  * failed. Errors have been reported to our stderr.
 456                  */
 457                 wait_or_whine(cmd->pid, cmd->argv[0]);
 458                 failed_errno = errno;
 459                 cmd->pid = -1;
 460         }
 461         close(notify_pipe[0]);
 462 }
 463 #else
 464 {
 465         int fhin = 0, fhout = 1, fherr = 2;
 466         const char **sargv = cmd->argv;
 467
 468         if (cmd->no_stdin)
 469                 fhin = open("/dev/null", O_RDWR);
 470         else if (need_in)
 471                 fhin = dup(fdin[0]);
 472         else if (cmd->in)
 473                 fhin = dup(cmd->in);
 474
 475         if (cmd->no_stderr)
 476                 fherr = open("/dev/null", O_RDWR);
 477         else if (need_err)
 478                 fherr = dup(fderr[1]);
 479         else if (cmd->err > 2)
 480                 fherr = dup(cmd->err);
 481
 482         if (cmd->no_stdout)
 483                 fhout = open("/dev/null", O_RDWR);
 484         else if (cmd->stdout_to_stderr)
 485                 fhout = dup(fherr);
 486         else if (need_out)
 487                 fhout = dup(fdout[1]);
 488         else if (cmd->out > 1)
 489                 fhout = dup(cmd->out);
 490
 491         if (cmd->git_cmd)
 492                 cmd->argv = prepare_git_cmd(cmd->argv);
 493         else if (cmd->use_shell)
 494                 cmd->argv = prepare_shell_cmd(cmd->argv);
 495
 496         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
 497                         cmd->dir, fhin, fhout, fherr);
 498         failed_errno = errno;
 499         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 500                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 501         if (cmd->clean_on_exit && cmd->pid >= 0)
 502                 mark_child_for_cleanup(cmd->pid);
 503
 504         if (cmd->git_cmd)
 505                 free(cmd->argv);
 506
 507         cmd->argv = sargv;
 508         if (fhin != 0)
 509                 close(fhin);
 510         if (fhout != 1)
 511                 close(fhout);
 512         if (fherr != 2)
 513                 close(fherr);
 514 }
 515 #endif
 516
 517         if (cmd->pid < 0) {
 518                 if (need_in)
 519                         close_pair(fdin);
 520                 else if (cmd->in)
 521                         close(cmd->in);
 522                 if (need_out)
 523                         close_pair(fdout);
 524                 else if (cmd->out)
 525                         close(cmd->out);
 526                 if (need_err)
 527                         close_pair(fderr);
 528                 else if (cmd->err)
 529                         close(cmd->err);
 530                 argv_array_clear(&cmd->args);
 531                 argv_array_clear(&cmd->env_array);
 532                 errno = failed_errno;
 533                 return -1;
 534         }
 535
 536         if (need_in)
 537                 close(fdin[0]);
 538         else if (cmd->in)
 539                 close(cmd->in);
 540
 541         if (need_out)
 542                 close(fdout[1]);
 543         else if (cmd->out)
 544                 close(cmd->out);
 545
 546         if (need_err)
 547                 close(fderr[1]);
 548         else if (cmd->err)
 549                 close(cmd->err);
 550
 551         return 0;
 552 }
 553
 554 int finish_command(struct child_process *cmd)
 555 {
 556         int ret = wait_or_whine(cmd->pid, cmd->argv[0]);
 557         argv_array_clear(&cmd->args);
 558         argv_array_clear(&cmd->env_array);
 559         return ret;
 560 }
 561
 562 int run_command(struct child_process *cmd)
 563 {
 564         int code = start_command(cmd);
 565         if (code)
 566                 return code;
 567         return finish_command(cmd);
 568 }
 569
 570 int run_command_v_opt(const char **argv, int opt)
 571 {
 572         return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
 573 }
 574
 575 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 576 {
 577         struct child_process cmd = CHILD_PROCESS_INIT;
 578         cmd.argv = argv;
 579         cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 580         cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 581         cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 582         cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 583         cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 584         cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 585         cmd.dir = dir;
 586         cmd.env = env;
 587         return run_command(&cmd);
 588 }
 589
 590 #ifndef NO_PTHREADS
 591 static pthread_t main_thread;
 592 static int main_thread_set;
 593 static pthread_key_t async_key;
 594 static pthread_key_t async_die_counter;
 595
 596 static void *run_thread(void *data)
 597 {
 598         struct async *async = data;
 599         intptr_t ret;
 600
 601         pthread_setspecific(async_key, async);
 602         ret = async->proc(async->proc_in, async->proc_out, async->data);
 603         return (void *)ret;
 604 }
 605
 606 static NORETURN void die_async(const char *err, va_list params)
 607 {
 608         vreportf("fatal: ", err, params);
 609
 610         if (!pthread_equal(main_thread, pthread_self())) {
 611                 struct async *async = pthread_getspecific(async_key);
 612                 if (async->proc_in >= 0)
 613                         close(async->proc_in);
 614                 if (async->proc_out >= 0)
 615                         close(async->proc_out);
 616                 pthread_exit((void *)128);
 617         }
 618
 619         exit(128);
 620 }
 621
 622 static int async_die_is_recursing(void)
 623 {
 624         void *ret = pthread_getspecific(async_die_counter);
 625         pthread_setspecific(async_die_counter, (void *)1);
 626         return ret != NULL;
 627 }
 628
 629 #else
 630
 631 static struct {
 632         void (**handlers)(void);
 633         size_t nr;
 634         size_t alloc;
 635 } git_atexit_hdlrs;
 636
 637 static int git_atexit_installed;
 638
 639 static void git_atexit_dispatch(void)
 640 {
 641         size_t i;
 642
 643         for (i=git_atexit_hdlrs.nr ; i ; i--)
 644                 git_atexit_hdlrs.handlers[i-1]();
 645 }
 646
 647 static void git_atexit_clear(void)
 648 {
 649         free(git_atexit_hdlrs.handlers);
 650         memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
 651         git_atexit_installed = 0;
 652 }
 653
 654 #undef atexit
 655 int git_atexit(void (*handler)(void))
 656 {
 657         ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
 658         git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
 659         if (!git_atexit_installed) {
 660                 if (atexit(&git_atexit_dispatch))
 661                         return -1;
 662                 git_atexit_installed = 1;
 663         }
 664         return 0;
 665 }
 666 #define atexit git_atexit
 667
 668 #endif
 669
 670 int start_async(struct async *async)
 671 {
 672         int need_in, need_out;
 673         int fdin[2], fdout[2];
 674         int proc_in, proc_out;
 675
 676         need_in = async->in < 0;
 677         if (need_in) {
 678                 if (pipe(fdin) < 0) {
 679                         if (async->out > 0)
 680                                 close(async->out);
 681                         return error("cannot create pipe: %s", strerror(errno));
 682                 }
 683                 async->in = fdin[1];
 684         }
 685
 686         need_out = async->out < 0;
 687         if (need_out) {
 688                 if (pipe(fdout) < 0) {
 689                         if (need_in)
 690                                 close_pair(fdin);
 691                         else if (async->in)
 692                                 close(async->in);
 693                         return error("cannot create pipe: %s", strerror(errno));
 694                 }
 695                 async->out = fdout[0];
 696         }
 697
 698         if (need_in)
 699                 proc_in = fdin[0];
 700         else if (async->in)
 701                 proc_in = async->in;
 702         else
 703                 proc_in = -1;
 704
 705         if (need_out)
 706                 proc_out = fdout[1];
 707         else if (async->out)
 708                 proc_out = async->out;
 709         else
 710                 proc_out = -1;
 711
 712 #ifdef NO_PTHREADS
 713         /* Flush stdio before fork() to avoid cloning buffers */
 714         fflush(NULL);
 715
 716         async->pid = fork();
 717         if (async->pid < 0) {
 718                 error("fork (async) failed: %s", strerror(errno));
 719                 goto error;
 720         }
 721         if (!async->pid) {
 722                 if (need_in)
 723                         close(fdin[1]);
 724                 if (need_out)
 725                         close(fdout[0]);
 726                 git_atexit_clear();
 727                 exit(!!async->proc(proc_in, proc_out, async->data));
 728         }
 729
 730         mark_child_for_cleanup(async->pid);
 731
 732         if (need_in)
 733                 close(fdin[0]);
 734         else if (async->in)
 735                 close(async->in);
 736
 737         if (need_out)
 738                 close(fdout[1]);
 739         else if (async->out)
 740                 close(async->out);
 741 #else
 742         if (!main_thread_set) {
 743                 /*
 744                  * We assume that the first time that start_async is called
 745                  * it is from the main thread.
 746                  */
 747                 main_thread_set = 1;
 748                 main_thread = pthread_self();
 749                 pthread_key_create(&async_key, NULL);
 750                 pthread_key_create(&async_die_counter, NULL);
 751                 set_die_routine(die_async);
 752                 set_die_is_recursing_routine(async_die_is_recursing);
 753         }
 754
 755         if (proc_in >= 0)
 756                 set_cloexec(proc_in);
 757         if (proc_out >= 0)
 758                 set_cloexec(proc_out);
 759         async->proc_in = proc_in;
 760         async->proc_out = proc_out;
 761         {
 762                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 763                 if (err) {
 764                         error("cannot create thread: %s", strerror(err));
 765                         goto error;
 766                 }
 767         }
 768 #endif
 769         return 0;
 770
 771 error:
 772         if (need_in)
 773                 close_pair(fdin);
 774         else if (async->in)
 775                 close(async->in);
 776
 777         if (need_out)
 778                 close_pair(fdout);
 779         else if (async->out)
 780                 close(async->out);
 781         return -1;
 782 }
 783
 784 int finish_async(struct async *async)
 785 {
 786 #ifdef NO_PTHREADS
 787         return wait_or_whine(async->pid, "child process");
 788 #else
 789         void *ret = (void *)(intptr_t)(-1);
 790
 791         if (pthread_join(async->tid, &ret))
 792                 error("pthread_join failed");
 793         return (int)(intptr_t)ret;
 794 #endif
 795 }
 796
 797 char *find_hook(const char *name)
 798 {
 799         char *path = git_path("hooks/%s", name);
 800         if (access(path, X_OK) < 0)
 801                 path = NULL;
 802
 803         return path;
 804 }
 805
 806 int run_hook_ve(const char *const *env, const char *name, va_list args)
 807 {
 808         struct child_process hook = CHILD_PROCESS_INIT;
 809         const char *p;
 810
 811         p = find_hook(name);
 812         if (!p)
 813                 return 0;
 814
 815         argv_array_push(&hook.args, p);
 816         while ((p = va_arg(args, const char *)))
 817                 argv_array_push(&hook.args, p);
 818         hook.env = env;
 819         hook.no_stdin = 1;
 820         hook.stdout_to_stderr = 1;
 821
 822         return run_command(&hook);
 823 }
 824
 825 int run_hook_le(const char *const *env, const char *name, ...)
 826 {
 827         va_list args;
 828         int ret;
 829
 830         va_start(args, name);
 831         ret = run_hook_ve(env, name, args);
 832         va_end(args);
 833
 834         return ret;
 835 }
 836
 837 int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint)
 838 {
 839         cmd->out = -1;
 840         if (start_command(cmd) < 0)
 841                 return -1;
 842
 843         if (strbuf_read(buf, cmd->out, hint) < 0) {
 844                 close(cmd->out);
 845                 finish_command(cmd); /* throw away exit code */
 846                 return -1;
 847         }
 848
 849         close(cmd->out);
 850         return finish_command(cmd);
 851 }