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, int in_signal)
  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                 if (!in_signal)
  28                         free(p);
  29         }
  30 }
  31
  32 static void cleanup_children_on_signal(int sig)
  33 {
  34         cleanup_children(sig, 1);
  35         sigchain_pop(sig);
  36         raise(sig);
  37 }
  38
  39 static void cleanup_children_on_exit(void)
  40 {
  41         cleanup_children(SIGTERM, 0);
  42 }
  43
  44 static void mark_child_for_cleanup(pid_t pid)
  45 {
  46         struct child_to_clean *p = xmalloc(sizeof(*p));
  47         p->pid = pid;
  48         p->next = children_to_clean;
  49         children_to_clean = p;
  50
  51         if (!installed_child_cleanup_handler) {
  52                 atexit(cleanup_children_on_exit);
  53                 sigchain_push_common(cleanup_children_on_signal);
  54                 installed_child_cleanup_handler = 1;
  55         }
  56 }
  57
  58 static void clear_child_for_cleanup(pid_t pid)
  59 {
  60         struct child_to_clean **pp;
  61
  62         for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
  63                 struct child_to_clean *clean_me = *pp;
  64
  65                 if (clean_me->pid == pid) {
  66                         *pp = clean_me->next;
  67                         free(clean_me);
  68                         return;
  69                 }
  70         }
  71 }
  72
  73 static inline void close_pair(int fd[2])
  74 {
  75         close(fd[0]);
  76         close(fd[1]);
  77 }
  78
  79 #ifndef GIT_WINDOWS_NATIVE
  80 static inline void dup_devnull(int to)
  81 {
  82         int fd = open("/dev/null", O_RDWR);
  83         if (fd < 0)
  84                 die_errno(_("open /dev/null failed"));
  85         if (dup2(fd, to) < 0)
  86                 die_errno(_("dup2(%d,%d) failed"), fd, to);
  87         close(fd);
  88 }
  89 #endif
  90
  91 static char *locate_in_PATH(const char *file)
  92 {
  93         const char *p = getenv("PATH");
  94         struct strbuf buf = STRBUF_INIT;
  95
  96         if (!p || !*p)
  97                 return NULL;
  98
  99         while (1) {
 100                 const char *end = strchrnul(p, ':');
 101
 102                 strbuf_reset(&buf);
 103
 104                 /* POSIX specifies an empty entry as the current directory. */
 105                 if (end != p) {
 106                         strbuf_add(&buf, p, end - p);
 107                         strbuf_addch(&buf, '/');
 108                 }
 109                 strbuf_addstr(&buf, file);
 110
 111                 if (!access(buf.buf, F_OK))
 112                         return strbuf_detach(&buf, NULL);
 113
 114                 if (!*end)
 115                         break;
 116                 p = end + 1;
 117         }
 118
 119         strbuf_release(&buf);
 120         return NULL;
 121 }
 122
 123 static int exists_in_PATH(const char *file)
 124 {
 125         char *r = locate_in_PATH(file);
 126         free(r);
 127         return r != NULL;
 128 }
 129
 130 int sane_execvp(const char *file, char * const argv[])
 131 {
 132         if (!execvp(file, argv))
 133                 return 0; /* cannot happen ;-) */
 134
 135         /*
 136          * When a command can't be found because one of the directories
 137          * listed in $PATH is unsearchable, execvp reports EACCES, but
 138          * careful usability testing (read: analysis of occasional bug
 139          * reports) reveals that "No such file or directory" is more
 140          * intuitive.
 141          *
 142          * We avoid commands with "/", because execvp will not do $PATH
 143          * lookups in that case.
 144          *
 145          * The reassignment of EACCES to errno looks like a no-op below,
 146          * but we need to protect against exists_in_PATH overwriting errno.
 147          */
 148         if (errno == EACCES && !strchr(file, '/'))
 149                 errno = exists_in_PATH(file) ? EACCES : ENOENT;
 150         else if (errno == ENOTDIR && !strchr(file, '/'))
 151                 errno = ENOENT;
 152         return -1;
 153 }
 154
 155 static const char **prepare_shell_cmd(const char **argv)
 156 {
 157         int argc, nargc = 0;
 158         const char **nargv;
 159
 160         for (argc = 0; argv[argc]; argc++)
 161                 ; /* just counting */
 162         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
 163         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
 164
 165         if (argc < 1)
 166                 die("BUG: shell command is empty");
 167
 168         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 169 #ifndef GIT_WINDOWS_NATIVE
 170                 nargv[nargc++] = SHELL_PATH;
 171 #else
 172                 nargv[nargc++] = "sh";
 173 #endif
 174                 nargv[nargc++] = "-c";
 175
 176                 if (argc < 2)
 177                         nargv[nargc++] = argv[0];
 178                 else {
 179                         struct strbuf arg0 = STRBUF_INIT;
 180                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 181                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
 182                 }
 183         }
 184
 185         for (argc = 0; argv[argc]; argc++)
 186                 nargv[nargc++] = argv[argc];
 187         nargv[nargc] = NULL;
 188
 189         return nargv;
 190 }
 191
 192 #ifndef GIT_WINDOWS_NATIVE
 193 static int execv_shell_cmd(const char **argv)
 194 {
 195         const char **nargv = prepare_shell_cmd(argv);
 196         trace_argv_printf(nargv, "trace: exec:");
 197         sane_execvp(nargv[0], (char **)nargv);
 198         free(nargv);
 199         return -1;
 200 }
 201 #endif
 202
 203 #ifndef GIT_WINDOWS_NATIVE
 204 static int child_err = 2;
 205 static int child_notifier = -1;
 206
 207 static void notify_parent(void)
 208 {
 209         /*
 210          * execvp failed.  If possible, we'd like to let start_command
 211          * know, so failures like ENOENT can be handled right away; but
 212          * otherwise, finish_command will still report the error.
 213          */
 214         xwrite(child_notifier, "", 1);
 215 }
 216
 217 static NORETURN void die_child(const char *err, va_list params)
 218 {
 219         vwritef(child_err, "fatal: ", err, params);
 220         exit(128);
 221 }
 222
 223 static void error_child(const char *err, va_list params)
 224 {
 225         vwritef(child_err, "error: ", err, params);
 226 }
 227 #endif
 228
 229 static inline void set_cloexec(int fd)
 230 {
 231         int flags = fcntl(fd, F_GETFD);
 232         if (flags >= 0)
 233                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 234 }
 235
 236 static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
 237 {
 238         int status, code = -1;
 239         pid_t waiting;
 240         int failed_errno = 0;
 241
 242         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 243                 ;       /* nothing */
 244         if (in_signal)
 245                 return 0;
 246
 247         if (waiting < 0) {
 248                 failed_errno = errno;
 249                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 250         } else if (waiting != pid) {
 251                 error("waitpid is confused (%s)", argv0);
 252         } else if (WIFSIGNALED(status)) {
 253                 code = WTERMSIG(status);
 254                 if (code != SIGINT && code != SIGQUIT)
 255                         error("%s died of signal %d", argv0, code);
 256                 /*
 257                  * This return value is chosen so that code & 0xff
 258                  * mimics the exit code that a POSIX shell would report for
 259                  * a program that died from this signal.
 260                  */
 261                 code += 128;
 262         } else if (WIFEXITED(status)) {
 263                 code = WEXITSTATUS(status);
 264                 /*
 265                  * Convert special exit code when execvp failed.
 266                  */
 267                 if (code == 127) {
 268                         code = -1;
 269                         failed_errno = ENOENT;
 270                 }
 271         } else {
 272                 error("waitpid is confused (%s)", argv0);
 273         }
 274
 275         clear_child_for_cleanup(pid);
 276
 277         errno = failed_errno;
 278         return code;
 279 }
 280
 281 int start_command(struct child_process *cmd)
 282 {
 283         int need_in, need_out, need_err;
 284         int fdin[2], fdout[2], fderr[2];
 285         int failed_errno;
 286         char *str;
 287
 288         if (!cmd->argv)
 289                 cmd->argv = cmd->args.argv;
 290         if (!cmd->env)
 291                 cmd->env = cmd->env_array.argv;
 292
 293         /*
 294          * In case of errors we must keep the promise to close FDs
 295          * that have been passed in via ->in and ->out.
 296          */
 297
 298         need_in = !cmd->no_stdin && cmd->in < 0;
 299         if (need_in) {
 300                 if (pipe(fdin) < 0) {
 301                         failed_errno = errno;
 302                         if (cmd->out > 0)
 303                                 close(cmd->out);
 304                         str = "standard input";
 305                         goto fail_pipe;
 306                 }
 307                 cmd->in = fdin[1];
 308         }
 309
 310         need_out = !cmd->no_stdout
 311                 && !cmd->stdout_to_stderr
 312                 && cmd->out < 0;
 313         if (need_out) {
 314                 if (pipe(fdout) < 0) {
 315                         failed_errno = errno;
 316                         if (need_in)
 317                                 close_pair(fdin);
 318                         else if (cmd->in)
 319                                 close(cmd->in);
 320                         str = "standard output";
 321                         goto fail_pipe;
 322                 }
 323                 cmd->out = fdout[0];
 324         }
 325
 326         need_err = !cmd->no_stderr && cmd->err < 0;
 327         if (need_err) {
 328                 if (pipe(fderr) < 0) {
 329                         failed_errno = errno;
 330                         if (need_in)
 331                                 close_pair(fdin);
 332                         else if (cmd->in)
 333                                 close(cmd->in);
 334                         if (need_out)
 335                                 close_pair(fdout);
 336                         else if (cmd->out)
 337                                 close(cmd->out);
 338                         str = "standard error";
 339 fail_pipe:
 340                         error("cannot create %s pipe for %s: %s",
 341                                 str, cmd->argv[0], strerror(failed_errno));
 342                         argv_array_clear(&cmd->args);
 343                         argv_array_clear(&cmd->env_array);
 344                         errno = failed_errno;
 345                         return -1;
 346                 }
 347                 cmd->err = fderr[0];
 348         }
 349
 350         trace_argv_printf(cmd->argv, "trace: run_command:");
 351         fflush(NULL);
 352
 353 #ifndef GIT_WINDOWS_NATIVE
 354 {
 355         int notify_pipe[2];
 356         if (pipe(notify_pipe))
 357                 notify_pipe[0] = notify_pipe[1] = -1;
 358
 359         cmd->pid = fork();
 360         failed_errno = errno;
 361         if (!cmd->pid) {
 362                 /*
 363                  * Redirect the channel to write syscall error messages to
 364                  * before redirecting the process's stderr so that all die()
 365                  * in subsequent call paths use the parent's stderr.
 366                  */
 367                 if (cmd->no_stderr || need_err) {
 368                         child_err = dup(2);
 369                         set_cloexec(child_err);
 370                 }
 371                 set_die_routine(die_child);
 372                 set_error_routine(error_child);
 373
 374                 close(notify_pipe[0]);
 375                 set_cloexec(notify_pipe[1]);
 376                 child_notifier = notify_pipe[1];
 377                 atexit(notify_parent);
 378
 379                 if (cmd->no_stdin)
 380                         dup_devnull(0);
 381                 else if (need_in) {
 382                         dup2(fdin[0], 0);
 383                         close_pair(fdin);
 384                 } else if (cmd->in) {
 385                         dup2(cmd->in, 0);
 386                         close(cmd->in);
 387                 }
 388
 389                 if (cmd->no_stderr)
 390                         dup_devnull(2);
 391                 else if (need_err) {
 392                         dup2(fderr[1], 2);
 393                         close_pair(fderr);
 394                 } else if (cmd->err > 1) {
 395                         dup2(cmd->err, 2);
 396                         close(cmd->err);
 397                 }
 398
 399                 if (cmd->no_stdout)
 400                         dup_devnull(1);
 401                 else if (cmd->stdout_to_stderr)
 402                         dup2(2, 1);
 403                 else if (need_out) {
 404                         dup2(fdout[1], 1);
 405                         close_pair(fdout);
 406                 } else if (cmd->out > 1) {
 407                         dup2(cmd->out, 1);
 408                         close(cmd->out);
 409                 }
 410
 411                 if (cmd->dir && chdir(cmd->dir))
 412                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 413                             cmd->dir);
 414                 if (cmd->env) {
 415                         for (; *cmd->env; cmd->env++) {
 416                                 if (strchr(*cmd->env, '='))
 417                                         putenv((char *)*cmd->env);
 418                                 else
 419                                         unsetenv(*cmd->env);
 420                         }
 421                 }
 422                 if (cmd->git_cmd)
 423                         execv_git_cmd(cmd->argv);
 424                 else if (cmd->use_shell)
 425                         execv_shell_cmd(cmd->argv);
 426                 else
 427                         sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 428                 if (errno == ENOENT) {
 429                         if (!cmd->silent_exec_failure)
 430                                 error("cannot run %s: %s", cmd->argv[0],
 431                                         strerror(ENOENT));
 432                         exit(127);
 433                 } else {
 434                         die_errno("cannot exec '%s'", cmd->argv[0]);
 435                 }
 436         }
 437         if (cmd->pid < 0)
 438                 error("cannot fork() for %s: %s", cmd->argv[0],
 439                         strerror(errno));
 440         else if (cmd->clean_on_exit)
 441                 mark_child_for_cleanup(cmd->pid);
 442
 443         /*
 444          * Wait for child's execvp. If the execvp succeeds (or if fork()
 445          * failed), EOF is seen immediately by the parent. Otherwise, the
 446          * child process sends a single byte.
 447          * Note that use of this infrastructure is completely advisory,
 448          * therefore, we keep error checks minimal.
 449          */
 450         close(notify_pipe[1]);
 451         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 452                 /*
 453                  * At this point we know that fork() succeeded, but execvp()
 454                  * failed. Errors have been reported to our stderr.
 455                  */
 456                 wait_or_whine(cmd->pid, cmd->argv[0], 0);
 457                 failed_errno = errno;
 458                 cmd->pid = -1;
 459         }
 460         close(notify_pipe[0]);
 461 }
 462 #else
 463 {
 464         int fhin = 0, fhout = 1, fherr = 2;
 465         const char **sargv = cmd->argv;
 466
 467         if (cmd->no_stdin)
 468                 fhin = open("/dev/null", O_RDWR);
 469         else if (need_in)
 470                 fhin = dup(fdin[0]);
 471         else if (cmd->in)
 472                 fhin = dup(cmd->in);
 473
 474         if (cmd->no_stderr)
 475                 fherr = open("/dev/null", O_RDWR);
 476         else if (need_err)
 477                 fherr = dup(fderr[1]);
 478         else if (cmd->err > 2)
 479                 fherr = dup(cmd->err);
 480
 481         if (cmd->no_stdout)
 482                 fhout = open("/dev/null", O_RDWR);
 483         else if (cmd->stdout_to_stderr)
 484                 fhout = dup(fherr);
 485         else if (need_out)
 486                 fhout = dup(fdout[1]);
 487         else if (cmd->out > 1)
 488                 fhout = dup(cmd->out);
 489
 490         if (cmd->git_cmd)
 491                 cmd->argv = prepare_git_cmd(cmd->argv);
 492         else if (cmd->use_shell)
 493                 cmd->argv = prepare_shell_cmd(cmd->argv);
 494
 495         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
 496                         cmd->dir, fhin, fhout, fherr);
 497         failed_errno = errno;
 498         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 499                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 500         if (cmd->clean_on_exit && cmd->pid >= 0)
 501                 mark_child_for_cleanup(cmd->pid);
 502
 503         if (cmd->git_cmd)
 504                 free(cmd->argv);
 505
 506         cmd->argv = sargv;
 507         if (fhin != 0)
 508                 close(fhin);
 509         if (fhout != 1)
 510                 close(fhout);
 511         if (fherr != 2)
 512                 close(fherr);
 513 }
 514 #endif
 515
 516         if (cmd->pid < 0) {
 517                 if (need_in)
 518                         close_pair(fdin);
 519                 else if (cmd->in)
 520                         close(cmd->in);
 521                 if (need_out)
 522                         close_pair(fdout);
 523                 else if (cmd->out)
 524                         close(cmd->out);
 525                 if (need_err)
 526                         close_pair(fderr);
 527                 else if (cmd->err)
 528                         close(cmd->err);
 529                 argv_array_clear(&cmd->args);
 530                 argv_array_clear(&cmd->env_array);
 531                 errno = failed_errno;
 532                 return -1;
 533         }
 534
 535         if (need_in)
 536                 close(fdin[0]);
 537         else if (cmd->in)
 538                 close(cmd->in);
 539
 540         if (need_out)
 541                 close(fdout[1]);
 542         else if (cmd->out)
 543                 close(cmd->out);
 544
 545         if (need_err)
 546                 close(fderr[1]);
 547         else if (cmd->err)
 548                 close(cmd->err);
 549
 550         return 0;
 551 }
 552
 553 int finish_command(struct child_process *cmd)
 554 {
 555         int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
 556         argv_array_clear(&cmd->args);
 557         argv_array_clear(&cmd->env_array);
 558         return ret;
 559 }
 560
 561 int finish_command_in_signal(struct child_process *cmd)
 562 {
 563         return wait_or_whine(cmd->pid, cmd->argv[0], 1);
 564 }
 565
 566
 567 int run_command(struct child_process *cmd)
 568 {
 569         int code;
 570
 571         if (cmd->out < 0 || cmd->err < 0)
 572                 die("BUG: run_command with a pipe can cause deadlock");
 573
 574         code = start_command(cmd);
 575         if (code)
 576                 return code;
 577         return finish_command(cmd);
 578 }
 579
 580 int run_command_v_opt(const char **argv, int opt)
 581 {
 582         return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
 583 }
 584
 585 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 586 {
 587         struct child_process cmd = CHILD_PROCESS_INIT;
 588         cmd.argv = argv;
 589         cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 590         cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 591         cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 592         cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 593         cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 594         cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 595         cmd.dir = dir;
 596         cmd.env = env;
 597         return run_command(&cmd);
 598 }
 599
 600 #ifndef NO_PTHREADS
 601 static pthread_t main_thread;
 602 static int main_thread_set;
 603 static pthread_key_t async_key;
 604 static pthread_key_t async_die_counter;
 605
 606 static void *run_thread(void *data)
 607 {
 608         struct async *async = data;
 609         intptr_t ret;
 610
 611         pthread_setspecific(async_key, async);
 612         ret = async->proc(async->proc_in, async->proc_out, async->data);
 613         return (void *)ret;
 614 }
 615
 616 static NORETURN void die_async(const char *err, va_list params)
 617 {
 618         vreportf("fatal: ", err, params);
 619
 620         if (!pthread_equal(main_thread, pthread_self())) {
 621                 struct async *async = pthread_getspecific(async_key);
 622                 if (async->proc_in >= 0)
 623                         close(async->proc_in);
 624                 if (async->proc_out >= 0)
 625                         close(async->proc_out);
 626                 pthread_exit((void *)128);
 627         }
 628
 629         exit(128);
 630 }
 631
 632 static int async_die_is_recursing(void)
 633 {
 634         void *ret = pthread_getspecific(async_die_counter);
 635         pthread_setspecific(async_die_counter, (void *)1);
 636         return ret != NULL;
 637 }
 638
 639 #else
 640
 641 static struct {
 642         void (**handlers)(void);
 643         size_t nr;
 644         size_t alloc;
 645 } git_atexit_hdlrs;
 646
 647 static int git_atexit_installed;
 648
 649 static void git_atexit_dispatch(void)
 650 {
 651         size_t i;
 652
 653         for (i=git_atexit_hdlrs.nr ; i ; i--)
 654                 git_atexit_hdlrs.handlers[i-1]();
 655 }
 656
 657 static void git_atexit_clear(void)
 658 {
 659         free(git_atexit_hdlrs.handlers);
 660         memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
 661         git_atexit_installed = 0;
 662 }
 663
 664 #undef atexit
 665 int git_atexit(void (*handler)(void))
 666 {
 667         ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
 668         git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
 669         if (!git_atexit_installed) {
 670                 if (atexit(&git_atexit_dispatch))
 671                         return -1;
 672                 git_atexit_installed = 1;
 673         }
 674         return 0;
 675 }
 676 #define atexit git_atexit
 677
 678 #endif
 679
 680 int start_async(struct async *async)
 681 {
 682         int need_in, need_out;
 683         int fdin[2], fdout[2];
 684         int proc_in, proc_out;
 685
 686         need_in = async->in < 0;
 687         if (need_in) {
 688                 if (pipe(fdin) < 0) {
 689                         if (async->out > 0)
 690                                 close(async->out);
 691                         return error("cannot create pipe: %s", strerror(errno));
 692                 }
 693                 async->in = fdin[1];
 694         }
 695
 696         need_out = async->out < 0;
 697         if (need_out) {
 698                 if (pipe(fdout) < 0) {
 699                         if (need_in)
 700                                 close_pair(fdin);
 701                         else if (async->in)
 702                                 close(async->in);
 703                         return error("cannot create pipe: %s", strerror(errno));
 704                 }
 705                 async->out = fdout[0];
 706         }
 707
 708         if (need_in)
 709                 proc_in = fdin[0];
 710         else if (async->in)
 711                 proc_in = async->in;
 712         else
 713                 proc_in = -1;
 714
 715         if (need_out)
 716                 proc_out = fdout[1];
 717         else if (async->out)
 718                 proc_out = async->out;
 719         else
 720                 proc_out = -1;
 721
 722 #ifdef NO_PTHREADS
 723         /* Flush stdio before fork() to avoid cloning buffers */
 724         fflush(NULL);
 725
 726         async->pid = fork();
 727         if (async->pid < 0) {
 728                 error("fork (async) failed: %s", strerror(errno));
 729                 goto error;
 730         }
 731         if (!async->pid) {
 732                 if (need_in)
 733                         close(fdin[1]);
 734                 if (need_out)
 735                         close(fdout[0]);
 736                 git_atexit_clear();
 737                 exit(!!async->proc(proc_in, proc_out, async->data));
 738         }
 739
 740         mark_child_for_cleanup(async->pid);
 741
 742         if (need_in)
 743                 close(fdin[0]);
 744         else if (async->in)
 745                 close(async->in);
 746
 747         if (need_out)
 748                 close(fdout[1]);
 749         else if (async->out)
 750                 close(async->out);
 751 #else
 752         if (!main_thread_set) {
 753                 /*
 754                  * We assume that the first time that start_async is called
 755                  * it is from the main thread.
 756                  */
 757                 main_thread_set = 1;
 758                 main_thread = pthread_self();
 759                 pthread_key_create(&async_key, NULL);
 760                 pthread_key_create(&async_die_counter, NULL);
 761                 set_die_routine(die_async);
 762                 set_die_is_recursing_routine(async_die_is_recursing);
 763         }
 764
 765         if (proc_in >= 0)
 766                 set_cloexec(proc_in);
 767         if (proc_out >= 0)
 768                 set_cloexec(proc_out);
 769         async->proc_in = proc_in;
 770         async->proc_out = proc_out;
 771         {
 772                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 773                 if (err) {
 774                         error("cannot create thread: %s", strerror(err));
 775                         goto error;
 776                 }
 777         }
 778 #endif
 779         return 0;
 780
 781 error:
 782         if (need_in)
 783                 close_pair(fdin);
 784         else if (async->in)
 785                 close(async->in);
 786
 787         if (need_out)
 788                 close_pair(fdout);
 789         else if (async->out)
 790                 close(async->out);
 791         return -1;
 792 }
 793
 794 int finish_async(struct async *async)
 795 {
 796 #ifdef NO_PTHREADS
 797         return wait_or_whine(async->pid, "child process", 0);
 798 #else
 799         void *ret = (void *)(intptr_t)(-1);
 800
 801         if (pthread_join(async->tid, &ret))
 802                 error("pthread_join failed");
 803         return (int)(intptr_t)ret;
 804 #endif
 805 }
 806
 807 const char *find_hook(const char *name)
 808 {
 809         const char *path = git_path("hooks/%s", name);
 810         if (access(path, X_OK) < 0)
 811                 path = NULL;
 812
 813         return path;
 814 }
 815
 816 int run_hook_ve(const char *const *env, const char *name, va_list args)
 817 {
 818         struct child_process hook = CHILD_PROCESS_INIT;
 819         const char *p;
 820
 821         p = find_hook(name);
 822         if (!p)
 823                 return 0;
 824
 825         argv_array_push(&hook.args, p);
 826         while ((p = va_arg(args, const char *)))
 827                 argv_array_push(&hook.args, p);
 828         hook.env = env;
 829         hook.no_stdin = 1;
 830         hook.stdout_to_stderr = 1;
 831
 832         return run_command(&hook);
 833 }
 834
 835 int run_hook_le(const char *const *env, const char *name, ...)
 836 {
 837         va_list args;
 838         int ret;
 839
 840         va_start(args, name);
 841         ret = run_hook_ve(env, name, args);
 842         va_end(args);
 843
 844         return ret;
 845 }
 846
 847 int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint)
 848 {
 849         cmd->out = -1;
 850         if (start_command(cmd) < 0)
 851                 return -1;
 852
 853         if (strbuf_read(buf, cmd->out, hint) < 0) {
 854                 close(cmd->out);
 855                 finish_command(cmd); /* throw away exit code */
 856                 return -1;
 857         }
 858
 859         close(cmd->out);
 860         return finish_command(cmd);
 861 }