Andrew's git / gitweb.git / run-command.c
?
run-command.con commit run-command: forbid using run_command with piped output (c29b396)
   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
  11void 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
  18struct child_to_clean {
  19        pid_t pid;
  20        struct child_to_clean *next;
  21};
  22static struct child_to_clean *children_to_clean;
  23static int installed_child_cleanup_handler;
  24
  25static 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
  35static void cleanup_children_on_signal(int sig)
  36{
  37        cleanup_children(sig);
  38        sigchain_pop(sig);
  39        raise(sig);
  40}
  41
  42static void cleanup_children_on_exit(void)
  43{
  44        cleanup_children(SIGTERM);
  45}
  46
  47static 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
  61static 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
  76static inline void close_pair(int fd[2])
  77{
  78        close(fd[0]);
  79        close(fd[1]);
  80}
  81
  82#ifndef GIT_WINDOWS_NATIVE
  83static 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
  94static 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
 126static int exists_in_PATH(const char *file)
 127{
 128        char *r = locate_in_PATH(file);
 129        free(r);
 130        return r != NULL;
 131}
 132
 133int 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
 158static 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
 196static 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
 207static int child_err = 2;
 208static int child_notifier = -1;
 209
 210static 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
 220static NORETURN void die_child(const char *err, va_list params)
 221{
 222        vwritef(child_err, "fatal: ", err, params);
 223        exit(128);
 224}
 225
 226static void error_child(const char *err, va_list params)
 227{
 228        vwritef(child_err, "error: ", err, params);
 229}
 230#endif
 231
 232static 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
 239static 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
 282int 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";
 340fail_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
 554int 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
 562int run_command(struct child_process *cmd)
 563{
 564        int code;
 565
 566        if (cmd->out < 0 || cmd->err < 0)
 567                die("BUG: run_command with a pipe can cause deadlock");
 568
 569        code = start_command(cmd);
 570        if (code)
 571                return code;
 572        return finish_command(cmd);
 573}
 574
 575int run_command_v_opt(const char **argv, int opt)
 576{
 577        return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
 578}
 579
 580int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 581{
 582        struct child_process cmd = CHILD_PROCESS_INIT;
 583        cmd.argv = argv;
 584        cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 585        cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 586        cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 587        cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 588        cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 589        cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 590        cmd.dir = dir;
 591        cmd.env = env;
 592        return run_command(&cmd);
 593}
 594
 595#ifndef NO_PTHREADS
 596static pthread_t main_thread;
 597static int main_thread_set;
 598static pthread_key_t async_key;
 599static pthread_key_t async_die_counter;
 600
 601static void *run_thread(void *data)
 602{
 603        struct async *async = data;
 604        intptr_t ret;
 605
 606        pthread_setspecific(async_key, async);
 607        ret = async->proc(async->proc_in, async->proc_out, async->data);
 608        return (void *)ret;
 609}
 610
 611static NORETURN void die_async(const char *err, va_list params)
 612{
 613        vreportf("fatal: ", err, params);
 614
 615        if (!pthread_equal(main_thread, pthread_self())) {
 616                struct async *async = pthread_getspecific(async_key);
 617                if (async->proc_in >= 0)
 618                        close(async->proc_in);
 619                if (async->proc_out >= 0)
 620                        close(async->proc_out);
 621                pthread_exit((void *)128);
 622        }
 623
 624        exit(128);
 625}
 626
 627static int async_die_is_recursing(void)
 628{
 629        void *ret = pthread_getspecific(async_die_counter);
 630        pthread_setspecific(async_die_counter, (void *)1);
 631        return ret != NULL;
 632}
 633
 634#else
 635
 636static struct {
 637        void (**handlers)(void);
 638        size_t nr;
 639        size_t alloc;
 640} git_atexit_hdlrs;
 641
 642static int git_atexit_installed;
 643
 644static void git_atexit_dispatch(void)
 645{
 646        size_t i;
 647
 648        for (i=git_atexit_hdlrs.nr ; i ; i--)
 649                git_atexit_hdlrs.handlers[i-1]();
 650}
 651
 652static void git_atexit_clear(void)
 653{
 654        free(git_atexit_hdlrs.handlers);
 655        memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
 656        git_atexit_installed = 0;
 657}
 658
 659#undef atexit
 660int git_atexit(void (*handler)(void))
 661{
 662        ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
 663        git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
 664        if (!git_atexit_installed) {
 665                if (atexit(&git_atexit_dispatch))
 666                        return -1;
 667                git_atexit_installed = 1;
 668        }
 669        return 0;
 670}
 671#define atexit git_atexit
 672
 673#endif
 674
 675int start_async(struct async *async)
 676{
 677        int need_in, need_out;
 678        int fdin[2], fdout[2];
 679        int proc_in, proc_out;
 680
 681        need_in = async->in < 0;
 682        if (need_in) {
 683                if (pipe(fdin) < 0) {
 684                        if (async->out > 0)
 685                                close(async->out);
 686                        return error("cannot create pipe: %s", strerror(errno));
 687                }
 688                async->in = fdin[1];
 689        }
 690
 691        need_out = async->out < 0;
 692        if (need_out) {
 693                if (pipe(fdout) < 0) {
 694                        if (need_in)
 695                                close_pair(fdin);
 696                        else if (async->in)
 697                                close(async->in);
 698                        return error("cannot create pipe: %s", strerror(errno));
 699                }
 700                async->out = fdout[0];
 701        }
 702
 703        if (need_in)
 704                proc_in = fdin[0];
 705        else if (async->in)
 706                proc_in = async->in;
 707        else
 708                proc_in = -1;
 709
 710        if (need_out)
 711                proc_out = fdout[1];
 712        else if (async->out)
 713                proc_out = async->out;
 714        else
 715                proc_out = -1;
 716
 717#ifdef NO_PTHREADS
 718        /* Flush stdio before fork() to avoid cloning buffers */
 719        fflush(NULL);
 720
 721        async->pid = fork();
 722        if (async->pid < 0) {
 723                error("fork (async) failed: %s", strerror(errno));
 724                goto error;
 725        }
 726        if (!async->pid) {
 727                if (need_in)
 728                        close(fdin[1]);
 729                if (need_out)
 730                        close(fdout[0]);
 731                git_atexit_clear();
 732                exit(!!async->proc(proc_in, proc_out, async->data));
 733        }
 734
 735        mark_child_for_cleanup(async->pid);
 736
 737        if (need_in)
 738                close(fdin[0]);
 739        else if (async->in)
 740                close(async->in);
 741
 742        if (need_out)
 743                close(fdout[1]);
 744        else if (async->out)
 745                close(async->out);
 746#else
 747        if (!main_thread_set) {
 748                /*
 749                 * We assume that the first time that start_async is called
 750                 * it is from the main thread.
 751                 */
 752                main_thread_set = 1;
 753                main_thread = pthread_self();
 754                pthread_key_create(&async_key, NULL);
 755                pthread_key_create(&async_die_counter, NULL);
 756                set_die_routine(die_async);
 757                set_die_is_recursing_routine(async_die_is_recursing);
 758        }
 759
 760        if (proc_in >= 0)
 761                set_cloexec(proc_in);
 762        if (proc_out >= 0)
 763                set_cloexec(proc_out);
 764        async->proc_in = proc_in;
 765        async->proc_out = proc_out;
 766        {
 767                int err = pthread_create(&async->tid, NULL, run_thread, async);
 768                if (err) {
 769                        error("cannot create thread: %s", strerror(err));
 770                        goto error;
 771                }
 772        }
 773#endif
 774        return 0;
 775
 776error:
 777        if (need_in)
 778                close_pair(fdin);
 779        else if (async->in)
 780                close(async->in);
 781
 782        if (need_out)
 783                close_pair(fdout);
 784        else if (async->out)
 785                close(async->out);
 786        return -1;
 787}
 788
 789int finish_async(struct async *async)
 790{
 791#ifdef NO_PTHREADS
 792        return wait_or_whine(async->pid, "child process");
 793#else
 794        void *ret = (void *)(intptr_t)(-1);
 795
 796        if (pthread_join(async->tid, &ret))
 797                error("pthread_join failed");
 798        return (int)(intptr_t)ret;
 799#endif
 800}
 801
 802char *find_hook(const char *name)
 803{
 804        char *path = git_path("hooks/%s", name);
 805        if (access(path, X_OK) < 0)
 806                path = NULL;
 807
 808        return path;
 809}
 810
 811int run_hook_ve(const char *const *env, const char *name, va_list args)
 812{
 813        struct child_process hook = CHILD_PROCESS_INIT;
 814        const char *p;
 815
 816        p = find_hook(name);
 817        if (!p)
 818                return 0;
 819
 820        argv_array_push(&hook.args, p);
 821        while ((p = va_arg(args, const char *)))
 822                argv_array_push(&hook.args, p);
 823        hook.env = env;
 824        hook.no_stdin = 1;
 825        hook.stdout_to_stderr = 1;
 826
 827        return run_command(&hook);
 828}
 829
 830int run_hook_le(const char *const *env, const char *name, ...)
 831{
 832        va_list args;
 833        int ret;
 834
 835        va_start(args, name);
 836        ret = run_hook_ve(env, name, args);
 837        va_end(args);
 838
 839        return ret;
 840}
 841
 842int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint)
 843{
 844        cmd->out = -1;
 845        if (start_command(cmd) < 0)
 846                return -1;
 847
 848        if (strbuf_read(buf, cmd->out, hint) < 0) {
 849                close(cmd->out);
 850                finish_command(cmd); /* throw away exit code */
 851                return -1;
 852        }
 853
 854        close(cmd->out);
 855        return finish_command(cmd);
 856}