Andrew's git / gitweb.git / run-command.c
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run-command.con commit run-command: teach async threads to ignore SIGPIPE (c792d7b)
   1#include "cache.h"
   2#include "run-command.h"
   3#include "exec_cmd.h"
   4#include "sigchain.h"
   5#include "argv-array.h"
   6
   7void 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
  14void child_process_clear(struct child_process *child)
  15{
  16        argv_array_clear(&child->args);
  17        argv_array_clear(&child->env_array);
  18}
  19
  20struct child_to_clean {
  21        pid_t pid;
  22        struct child_to_clean *next;
  23};
  24static struct child_to_clean *children_to_clean;
  25static int installed_child_cleanup_handler;
  26
  27static 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
  38static void cleanup_children_on_signal(int sig)
  39{
  40        cleanup_children(sig, 1);
  41        sigchain_pop(sig);
  42        raise(sig);
  43}
  44
  45static void cleanup_children_on_exit(void)
  46{
  47        cleanup_children(SIGTERM, 0);
  48}
  49
  50static 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
  64static 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
  79static inline void close_pair(int fd[2])
  80{
  81        close(fd[0]);
  82        close(fd[1]);
  83}
  84
  85#ifndef GIT_WINDOWS_NATIVE
  86static 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
  97static 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
 129static int exists_in_PATH(const char *file)
 130{
 131        char *r = locate_in_PATH(file);
 132        free(r);
 133        return r != NULL;
 134}
 135
 136int 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 $PATH
 149         * lookups in that case.
 150         *
 151         * The reassignment of EACCES to errno looks like a no-op below,
 152         * but we need to protect against exists_in_PATH overwriting errno.
 153         */
 154        if (errno == EACCES && !strchr(file, '/'))
 155                errno = exists_in_PATH(file) ? EACCES : ENOENT;
 156        else if (errno == ENOTDIR && !strchr(file, '/'))
 157                errno = ENOENT;
 158        return -1;
 159}
 160
 161static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
 162{
 163        if (!argv[0])
 164                die("BUG: shell command is empty");
 165
 166        if (strcspn(argv[0], "|&;<>()$`\\\"' \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
 189static 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
 201static int child_notifier = -1;
 202
 203static 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
 214static 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
 221static 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
 266int 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";
 324fail_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
 534int 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
 541int finish_command_in_signal(struct child_process *cmd)
 542{
 543        return wait_or_whine(cmd->pid, cmd->argv[0], 1);
 544}
 545
 546
 547int 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
 560int run_command_v_opt(const char **argv, int opt)
 561{
 562        return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
 563}
 564
 565int 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
 581static pthread_t main_thread;
 582static int main_thread_set;
 583static pthread_key_t async_key;
 584static pthread_key_t async_die_counter;
 585
 586static void *run_thread(void *data)
 587{
 588        struct async *async = data;
 589        intptr_t ret;
 590
 591        if (async->isolate_sigpipe) {
 592                sigset_t mask;
 593                sigemptyset(&mask);
 594                sigaddset(&mask, SIGPIPE);
 595                if (pthread_sigmask(SIG_BLOCK, &mask, NULL) < 0) {
 596                        ret = error("unable to block SIGPIPE in async thread");
 597                        return (void *)ret;
 598                }
 599        }
 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
 606static NORETURN void die_async(const char *err, va_list params)
 607{
 608        vreportf("fatal: ", err, params);
 609
 610        if (in_async()) {
 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
 622static 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
 629int in_async(void)
 630{
 631        if (!main_thread_set)
 632                return 0; /* no asyncs started yet */
 633        return !pthread_equal(main_thread, pthread_self());
 634}
 635
 636void NORETURN async_exit(int code)
 637{
 638        pthread_exit((void *)(intptr_t)code);
 639}
 640
 641#else
 642
 643static struct {
 644        void (**handlers)(void);
 645        size_t nr;
 646        size_t alloc;
 647} git_atexit_hdlrs;
 648
 649static int git_atexit_installed;
 650
 651static void git_atexit_dispatch(void)
 652{
 653        size_t i;
 654
 655        for (i=git_atexit_hdlrs.nr ; i ; i--)
 656                git_atexit_hdlrs.handlers[i-1]();
 657}
 658
 659static void git_atexit_clear(void)
 660{
 661        free(git_atexit_hdlrs.handlers);
 662        memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
 663        git_atexit_installed = 0;
 664}
 665
 666#undef atexit
 667int git_atexit(void (*handler)(void))
 668{
 669        ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
 670        git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
 671        if (!git_atexit_installed) {
 672                if (atexit(&git_atexit_dispatch))
 673                        return -1;
 674                git_atexit_installed = 1;
 675        }
 676        return 0;
 677}
 678#define atexit git_atexit
 679
 680static int process_is_async;
 681int in_async(void)
 682{
 683        return process_is_async;
 684}
 685
 686void NORETURN async_exit(int code)
 687{
 688        exit(code);
 689}
 690
 691#endif
 692
 693int start_async(struct async *async)
 694{
 695        int need_in, need_out;
 696        int fdin[2], fdout[2];
 697        int proc_in, proc_out;
 698
 699        need_in = async->in < 0;
 700        if (need_in) {
 701                if (pipe(fdin) < 0) {
 702                        if (async->out > 0)
 703                                close(async->out);
 704                        return error("cannot create pipe: %s", strerror(errno));
 705                }
 706                async->in = fdin[1];
 707        }
 708
 709        need_out = async->out < 0;
 710        if (need_out) {
 711                if (pipe(fdout) < 0) {
 712                        if (need_in)
 713                                close_pair(fdin);
 714                        else if (async->in)
 715                                close(async->in);
 716                        return error("cannot create pipe: %s", strerror(errno));
 717                }
 718                async->out = fdout[0];
 719        }
 720
 721        if (need_in)
 722                proc_in = fdin[0];
 723        else if (async->in)
 724                proc_in = async->in;
 725        else
 726                proc_in = -1;
 727
 728        if (need_out)
 729                proc_out = fdout[1];
 730        else if (async->out)
 731                proc_out = async->out;
 732        else
 733                proc_out = -1;
 734
 735#ifdef NO_PTHREADS
 736        /* Flush stdio before fork() to avoid cloning buffers */
 737        fflush(NULL);
 738
 739        async->pid = fork();
 740        if (async->pid < 0) {
 741                error("fork (async) failed: %s", strerror(errno));
 742                goto error;
 743        }
 744        if (!async->pid) {
 745                if (need_in)
 746                        close(fdin[1]);
 747                if (need_out)
 748                        close(fdout[0]);
 749                git_atexit_clear();
 750                process_is_async = 1;
 751                exit(!!async->proc(proc_in, proc_out, async->data));
 752        }
 753
 754        mark_child_for_cleanup(async->pid);
 755
 756        if (need_in)
 757                close(fdin[0]);
 758        else if (async->in)
 759                close(async->in);
 760
 761        if (need_out)
 762                close(fdout[1]);
 763        else if (async->out)
 764                close(async->out);
 765#else
 766        if (!main_thread_set) {
 767                /*
 768                 * We assume that the first time that start_async is called
 769                 * it is from the main thread.
 770                 */
 771                main_thread_set = 1;
 772                main_thread = pthread_self();
 773                pthread_key_create(&async_key, NULL);
 774                pthread_key_create(&async_die_counter, NULL);
 775                set_die_routine(die_async);
 776                set_die_is_recursing_routine(async_die_is_recursing);
 777        }
 778
 779        if (proc_in >= 0)
 780                set_cloexec(proc_in);
 781        if (proc_out >= 0)
 782                set_cloexec(proc_out);
 783        async->proc_in = proc_in;
 784        async->proc_out = proc_out;
 785        {
 786                int err = pthread_create(&async->tid, NULL, run_thread, async);
 787                if (err) {
 788                        error("cannot create thread: %s", strerror(err));
 789                        goto error;
 790                }
 791        }
 792#endif
 793        return 0;
 794
 795error:
 796        if (need_in)
 797                close_pair(fdin);
 798        else if (async->in)
 799                close(async->in);
 800
 801        if (need_out)
 802                close_pair(fdout);
 803        else if (async->out)
 804                close(async->out);
 805        return -1;
 806}
 807
 808int finish_async(struct async *async)
 809{
 810#ifdef NO_PTHREADS
 811        return wait_or_whine(async->pid, "child process", 0);
 812#else
 813        void *ret = (void *)(intptr_t)(-1);
 814
 815        if (pthread_join(async->tid, &ret))
 816                error("pthread_join failed");
 817        return (int)(intptr_t)ret;
 818#endif
 819}
 820
 821const char *find_hook(const char *name)
 822{
 823        static struct strbuf path = STRBUF_INIT;
 824
 825        strbuf_reset(&path);
 826        strbuf_git_path(&path, "hooks/%s", name);
 827        if (access(path.buf, X_OK) < 0)
 828                return NULL;
 829        return path.buf;
 830}
 831
 832int run_hook_ve(const char *const *env, const char *name, va_list args)
 833{
 834        struct child_process hook = CHILD_PROCESS_INIT;
 835        const char *p;
 836
 837        p = find_hook(name);
 838        if (!p)
 839                return 0;
 840
 841        argv_array_push(&hook.args, p);
 842        while ((p = va_arg(args, const char *)))
 843                argv_array_push(&hook.args, p);
 844        hook.env = env;
 845        hook.no_stdin = 1;
 846        hook.stdout_to_stderr = 1;
 847
 848        return run_command(&hook);
 849}
 850
 851int run_hook_le(const char *const *env, const char *name, ...)
 852{
 853        va_list args;
 854        int ret;
 855
 856        va_start(args, name);
 857        ret = run_hook_ve(env, name, args);
 858        va_end(args);
 859
 860        return ret;
 861}
 862
 863int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint)
 864{
 865        cmd->out = -1;
 866        if (start_command(cmd) < 0)
 867                return -1;
 868
 869        if (strbuf_read(buf, cmd->out, hint) < 0) {
 870                close(cmd->out);
 871                finish_command(cmd); /* throw away exit code */
 872                return -1;
 873        }
 874
 875        close(cmd->out);
 876        return finish_command(cmd);
 877}