Andrew's git / gitweb.git / run-command.c
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run-command.con commit mailinfo: move patch_lines to struct mailinfo (43550ef)
   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
  14struct child_to_clean {
  15        pid_t pid;
  16        struct child_to_clean *next;
  17};
  18static struct child_to_clean *children_to_clean;
  19static int installed_child_cleanup_handler;
  20
  21static void cleanup_children(int sig)
  22{
  23        while (children_to_clean) {
  24                struct child_to_clean *p = children_to_clean;
  25                children_to_clean = p->next;
  26                kill(p->pid, sig);
  27                free(p);
  28        }
  29}
  30
  31static void cleanup_children_on_signal(int sig)
  32{
  33        cleanup_children(sig);
  34        sigchain_pop(sig);
  35        raise(sig);
  36}
  37
  38static void cleanup_children_on_exit(void)
  39{
  40        cleanup_children(SIGTERM);
  41}
  42
  43static void mark_child_for_cleanup(pid_t pid)
  44{
  45        struct child_to_clean *p = xmalloc(sizeof(*p));
  46        p->pid = pid;
  47        p->next = children_to_clean;
  48        children_to_clean = p;
  49
  50        if (!installed_child_cleanup_handler) {
  51                atexit(cleanup_children_on_exit);
  52                sigchain_push_common(cleanup_children_on_signal);
  53                installed_child_cleanup_handler = 1;
  54        }
  55}
  56
  57static void clear_child_for_cleanup(pid_t pid)
  58{
  59        struct child_to_clean **pp;
  60
  61        for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
  62                struct child_to_clean *clean_me = *pp;
  63
  64                if (clean_me->pid == pid) {
  65                        *pp = clean_me->next;
  66                        free(clean_me);
  67                        return;
  68                }
  69        }
  70}
  71
  72static inline void close_pair(int fd[2])
  73{
  74        close(fd[0]);
  75        close(fd[1]);
  76}
  77
  78#ifndef GIT_WINDOWS_NATIVE
  79static inline void dup_devnull(int to)
  80{
  81        int fd = open("/dev/null", O_RDWR);
  82        if (fd < 0)
  83                die_errno(_("open /dev/null failed"));
  84        if (dup2(fd, to) < 0)
  85                die_errno(_("dup2(%d,%d) failed"), fd, to);
  86        close(fd);
  87}
  88#endif
  89
  90static char *locate_in_PATH(const char *file)
  91{
  92        const char *p = getenv("PATH");
  93        struct strbuf buf = STRBUF_INIT;
  94
  95        if (!p || !*p)
  96                return NULL;
  97
  98        while (1) {
  99                const char *end = strchrnul(p, ':');
 100
 101                strbuf_reset(&buf);
 102
 103                /* POSIX specifies an empty entry as the current directory. */
 104                if (end != p) {
 105                        strbuf_add(&buf, p, end - p);
 106                        strbuf_addch(&buf, '/');
 107                }
 108                strbuf_addstr(&buf, file);
 109
 110                if (!access(buf.buf, F_OK))
 111                        return strbuf_detach(&buf, NULL);
 112
 113                if (!*end)
 114                        break;
 115                p = end + 1;
 116        }
 117
 118        strbuf_release(&buf);
 119        return NULL;
 120}
 121
 122static int exists_in_PATH(const char *file)
 123{
 124        char *r = locate_in_PATH(file);
 125        free(r);
 126        return r != NULL;
 127}
 128
 129int sane_execvp(const char *file, char * const argv[])
 130{
 131        if (!execvp(file, argv))
 132                return 0; /* cannot happen ;-) */
 133
 134        /*
 135         * When a command can't be found because one of the directories
 136         * listed in $PATH is unsearchable, execvp reports EACCES, but
 137         * careful usability testing (read: analysis of occasional bug
 138         * reports) reveals that "No such file or directory" is more
 139         * intuitive.
 140         *
 141         * We avoid commands with "/", because execvp will not do $PATH
 142         * lookups in that case.
 143         *
 144         * The reassignment of EACCES to errno looks like a no-op below,
 145         * but we need to protect against exists_in_PATH overwriting errno.
 146         */
 147        if (errno == EACCES && !strchr(file, '/'))
 148                errno = exists_in_PATH(file) ? EACCES : ENOENT;
 149        else if (errno == ENOTDIR && !strchr(file, '/'))
 150                errno = ENOENT;
 151        return -1;
 152}
 153
 154static const char **prepare_shell_cmd(const char **argv)
 155{
 156        int argc, nargc = 0;
 157        const char **nargv;
 158
 159        for (argc = 0; argv[argc]; argc++)
 160                ; /* just counting */
 161        /* +1 for NULL, +3 for "sh -c" plus extra $0 */
 162        nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
 163
 164        if (argc < 1)
 165                die("BUG: shell command is empty");
 166
 167        if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 168#ifndef GIT_WINDOWS_NATIVE
 169                nargv[nargc++] = SHELL_PATH;
 170#else
 171                nargv[nargc++] = "sh";
 172#endif
 173                nargv[nargc++] = "-c";
 174
 175                if (argc < 2)
 176                        nargv[nargc++] = argv[0];
 177                else {
 178                        struct strbuf arg0 = STRBUF_INIT;
 179                        strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 180                        nargv[nargc++] = strbuf_detach(&arg0, NULL);
 181                }
 182        }
 183
 184        for (argc = 0; argv[argc]; argc++)
 185                nargv[nargc++] = argv[argc];
 186        nargv[nargc] = NULL;
 187
 188        return nargv;
 189}
 190
 191#ifndef GIT_WINDOWS_NATIVE
 192static int execv_shell_cmd(const char **argv)
 193{
 194        const char **nargv = prepare_shell_cmd(argv);
 195        trace_argv_printf(nargv, "trace: exec:");
 196        sane_execvp(nargv[0], (char **)nargv);
 197        free(nargv);
 198        return -1;
 199}
 200#endif
 201
 202#ifndef GIT_WINDOWS_NATIVE
 203static int child_notifier = -1;
 204
 205static void notify_parent(void)
 206{
 207        /*
 208         * execvp failed.  If possible, we'd like to let start_command
 209         * know, so failures like ENOENT can be handled right away; but
 210         * otherwise, finish_command will still report the error.
 211         */
 212        xwrite(child_notifier, "", 1);
 213}
 214#endif
 215
 216static inline void set_cloexec(int fd)
 217{
 218        int flags = fcntl(fd, F_GETFD);
 219        if (flags >= 0)
 220                fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 221}
 222
 223static int wait_or_whine(pid_t pid, const char *argv0)
 224{
 225        int status, code = -1;
 226        pid_t waiting;
 227        int failed_errno = 0;
 228
 229        while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 230                ;       /* nothing */
 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                        argv_array_clear(&cmd->args);
 328                        argv_array_clear(&cmd->env_array);
 329                        errno = failed_errno;
 330                        return -1;
 331                }
 332                cmd->err = fderr[0];
 333        }
 334
 335        trace_argv_printf(cmd->argv, "trace: run_command:");
 336        fflush(NULL);
 337
 338#ifndef GIT_WINDOWS_NATIVE
 339{
 340        int notify_pipe[2];
 341        if (pipe(notify_pipe))
 342                notify_pipe[0] = notify_pipe[1] = -1;
 343
 344        cmd->pid = fork();
 345        failed_errno = errno;
 346        if (!cmd->pid) {
 347                /*
 348                 * Redirect the channel to write syscall error messages to
 349                 * before redirecting the process's stderr so that all die()
 350                 * in subsequent call paths use the parent's stderr.
 351                 */
 352                if (cmd->no_stderr || need_err) {
 353                        int child_err = dup(2);
 354                        set_cloexec(child_err);
 355                        set_error_handle(fdopen(child_err, "w"));
 356                }
 357
 358                close(notify_pipe[0]);
 359                set_cloexec(notify_pipe[1]);
 360                child_notifier = notify_pipe[1];
 361                atexit(notify_parent);
 362
 363                if (cmd->no_stdin)
 364                        dup_devnull(0);
 365                else if (need_in) {
 366                        dup2(fdin[0], 0);
 367                        close_pair(fdin);
 368                } else if (cmd->in) {
 369                        dup2(cmd->in, 0);
 370                        close(cmd->in);
 371                }
 372
 373                if (cmd->no_stderr)
 374                        dup_devnull(2);
 375                else if (need_err) {
 376                        dup2(fderr[1], 2);
 377                        close_pair(fderr);
 378                } else if (cmd->err > 1) {
 379                        dup2(cmd->err, 2);
 380                        close(cmd->err);
 381                }
 382
 383                if (cmd->no_stdout)
 384                        dup_devnull(1);
 385                else if (cmd->stdout_to_stderr)
 386                        dup2(2, 1);
 387                else if (need_out) {
 388                        dup2(fdout[1], 1);
 389                        close_pair(fdout);
 390                } else if (cmd->out > 1) {
 391                        dup2(cmd->out, 1);
 392                        close(cmd->out);
 393                }
 394
 395                if (cmd->dir && chdir(cmd->dir))
 396                        die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 397                            cmd->dir);
 398                if (cmd->env) {
 399                        for (; *cmd->env; cmd->env++) {
 400                                if (strchr(*cmd->env, '='))
 401                                        putenv((char *)*cmd->env);
 402                                else
 403                                        unsetenv(*cmd->env);
 404                        }
 405                }
 406                if (cmd->git_cmd)
 407                        execv_git_cmd(cmd->argv);
 408                else if (cmd->use_shell)
 409                        execv_shell_cmd(cmd->argv);
 410                else
 411                        sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 412                if (errno == ENOENT) {
 413                        if (!cmd->silent_exec_failure)
 414                                error("cannot run %s: %s", cmd->argv[0],
 415                                        strerror(ENOENT));
 416                        exit(127);
 417                } else {
 418                        die_errno("cannot exec '%s'", cmd->argv[0]);
 419                }
 420        }
 421        if (cmd->pid < 0)
 422                error("cannot fork() for %s: %s", cmd->argv[0],
 423                        strerror(errno));
 424        else if (cmd->clean_on_exit)
 425                mark_child_for_cleanup(cmd->pid);
 426
 427        /*
 428         * Wait for child's execvp. If the execvp succeeds (or if fork()
 429         * failed), EOF is seen immediately by the parent. Otherwise, the
 430         * child process sends a single byte.
 431         * Note that use of this infrastructure is completely advisory,
 432         * therefore, we keep error checks minimal.
 433         */
 434        close(notify_pipe[1]);
 435        if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 436                /*
 437                 * At this point we know that fork() succeeded, but execvp()
 438                 * failed. Errors have been reported to our stderr.
 439                 */
 440                wait_or_whine(cmd->pid, cmd->argv[0]);
 441                failed_errno = errno;
 442                cmd->pid = -1;
 443        }
 444        close(notify_pipe[0]);
 445}
 446#else
 447{
 448        int fhin = 0, fhout = 1, fherr = 2;
 449        const char **sargv = cmd->argv;
 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(cmd->argv);
 476        else if (cmd->use_shell)
 477                cmd->argv = prepare_shell_cmd(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        if (cmd->git_cmd)
 488                free(cmd->argv);
 489
 490        cmd->argv = sargv;
 491        if (fhin != 0)
 492                close(fhin);
 493        if (fhout != 1)
 494                close(fhout);
 495        if (fherr != 2)
 496                close(fherr);
 497}
 498#endif
 499
 500        if (cmd->pid < 0) {
 501                if (need_in)
 502                        close_pair(fdin);
 503                else if (cmd->in)
 504                        close(cmd->in);
 505                if (need_out)
 506                        close_pair(fdout);
 507                else if (cmd->out)
 508                        close(cmd->out);
 509                if (need_err)
 510                        close_pair(fderr);
 511                else if (cmd->err)
 512                        close(cmd->err);
 513                argv_array_clear(&cmd->args);
 514                argv_array_clear(&cmd->env_array);
 515                errno = failed_errno;
 516                return -1;
 517        }
 518
 519        if (need_in)
 520                close(fdin[0]);
 521        else if (cmd->in)
 522                close(cmd->in);
 523
 524        if (need_out)
 525                close(fdout[1]);
 526        else if (cmd->out)
 527                close(cmd->out);
 528
 529        if (need_err)
 530                close(fderr[1]);
 531        else if (cmd->err)
 532                close(cmd->err);
 533
 534        return 0;
 535}
 536
 537int finish_command(struct child_process *cmd)
 538{
 539        int ret = wait_or_whine(cmd->pid, cmd->argv[0]);
 540        argv_array_clear(&cmd->args);
 541        argv_array_clear(&cmd->env_array);
 542        return ret;
 543}
 544
 545int run_command(struct child_process *cmd)
 546{
 547        int code;
 548
 549        if (cmd->out < 0 || cmd->err < 0)
 550                die("BUG: run_command with a pipe can cause deadlock");
 551
 552        code = start_command(cmd);
 553        if (code)
 554                return code;
 555        return finish_command(cmd);
 556}
 557
 558int run_command_v_opt(const char **argv, int opt)
 559{
 560        return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
 561}
 562
 563int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 564{
 565        struct child_process cmd = CHILD_PROCESS_INIT;
 566        cmd.argv = argv;
 567        cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 568        cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 569        cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 570        cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 571        cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 572        cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 573        cmd.dir = dir;
 574        cmd.env = env;
 575        return run_command(&cmd);
 576}
 577
 578#ifndef NO_PTHREADS
 579static pthread_t main_thread;
 580static int main_thread_set;
 581static pthread_key_t async_key;
 582static pthread_key_t async_die_counter;
 583
 584static void *run_thread(void *data)
 585{
 586        struct async *async = data;
 587        intptr_t ret;
 588
 589        pthread_setspecific(async_key, async);
 590        ret = async->proc(async->proc_in, async->proc_out, async->data);
 591        return (void *)ret;
 592}
 593
 594static NORETURN void die_async(const char *err, va_list params)
 595{
 596        vreportf("fatal: ", err, params);
 597
 598        if (!pthread_equal(main_thread, pthread_self())) {
 599                struct async *async = pthread_getspecific(async_key);
 600                if (async->proc_in >= 0)
 601                        close(async->proc_in);
 602                if (async->proc_out >= 0)
 603                        close(async->proc_out);
 604                pthread_exit((void *)128);
 605        }
 606
 607        exit(128);
 608}
 609
 610static int async_die_is_recursing(void)
 611{
 612        void *ret = pthread_getspecific(async_die_counter);
 613        pthread_setspecific(async_die_counter, (void *)1);
 614        return ret != NULL;
 615}
 616
 617#else
 618
 619static struct {
 620        void (**handlers)(void);
 621        size_t nr;
 622        size_t alloc;
 623} git_atexit_hdlrs;
 624
 625static int git_atexit_installed;
 626
 627static void git_atexit_dispatch(void)
 628{
 629        size_t i;
 630
 631        for (i=git_atexit_hdlrs.nr ; i ; i--)
 632                git_atexit_hdlrs.handlers[i-1]();
 633}
 634
 635static void git_atexit_clear(void)
 636{
 637        free(git_atexit_hdlrs.handlers);
 638        memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
 639        git_atexit_installed = 0;
 640}
 641
 642#undef atexit
 643int git_atexit(void (*handler)(void))
 644{
 645        ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
 646        git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
 647        if (!git_atexit_installed) {
 648                if (atexit(&git_atexit_dispatch))
 649                        return -1;
 650                git_atexit_installed = 1;
 651        }
 652        return 0;
 653}
 654#define atexit git_atexit
 655
 656#endif
 657
 658int start_async(struct async *async)
 659{
 660        int need_in, need_out;
 661        int fdin[2], fdout[2];
 662        int proc_in, proc_out;
 663
 664        need_in = async->in < 0;
 665        if (need_in) {
 666                if (pipe(fdin) < 0) {
 667                        if (async->out > 0)
 668                                close(async->out);
 669                        return error("cannot create pipe: %s", strerror(errno));
 670                }
 671                async->in = fdin[1];
 672        }
 673
 674        need_out = async->out < 0;
 675        if (need_out) {
 676                if (pipe(fdout) < 0) {
 677                        if (need_in)
 678                                close_pair(fdin);
 679                        else if (async->in)
 680                                close(async->in);
 681                        return error("cannot create pipe: %s", strerror(errno));
 682                }
 683                async->out = fdout[0];
 684        }
 685
 686        if (need_in)
 687                proc_in = fdin[0];
 688        else if (async->in)
 689                proc_in = async->in;
 690        else
 691                proc_in = -1;
 692
 693        if (need_out)
 694                proc_out = fdout[1];
 695        else if (async->out)
 696                proc_out = async->out;
 697        else
 698                proc_out = -1;
 699
 700#ifdef NO_PTHREADS
 701        /* Flush stdio before fork() to avoid cloning buffers */
 702        fflush(NULL);
 703
 704        async->pid = fork();
 705        if (async->pid < 0) {
 706                error("fork (async) failed: %s", strerror(errno));
 707                goto error;
 708        }
 709        if (!async->pid) {
 710                if (need_in)
 711                        close(fdin[1]);
 712                if (need_out)
 713                        close(fdout[0]);
 714                git_atexit_clear();
 715                exit(!!async->proc(proc_in, proc_out, async->data));
 716        }
 717
 718        mark_child_for_cleanup(async->pid);
 719
 720        if (need_in)
 721                close(fdin[0]);
 722        else if (async->in)
 723                close(async->in);
 724
 725        if (need_out)
 726                close(fdout[1]);
 727        else if (async->out)
 728                close(async->out);
 729#else
 730        if (!main_thread_set) {
 731                /*
 732                 * We assume that the first time that start_async is called
 733                 * it is from the main thread.
 734                 */
 735                main_thread_set = 1;
 736                main_thread = pthread_self();
 737                pthread_key_create(&async_key, NULL);
 738                pthread_key_create(&async_die_counter, NULL);
 739                set_die_routine(die_async);
 740                set_die_is_recursing_routine(async_die_is_recursing);
 741        }
 742
 743        if (proc_in >= 0)
 744                set_cloexec(proc_in);
 745        if (proc_out >= 0)
 746                set_cloexec(proc_out);
 747        async->proc_in = proc_in;
 748        async->proc_out = proc_out;
 749        {
 750                int err = pthread_create(&async->tid, NULL, run_thread, async);
 751                if (err) {
 752                        error("cannot create thread: %s", strerror(err));
 753                        goto error;
 754                }
 755        }
 756#endif
 757        return 0;
 758
 759error:
 760        if (need_in)
 761                close_pair(fdin);
 762        else if (async->in)
 763                close(async->in);
 764
 765        if (need_out)
 766                close_pair(fdout);
 767        else if (async->out)
 768                close(async->out);
 769        return -1;
 770}
 771
 772int finish_async(struct async *async)
 773{
 774#ifdef NO_PTHREADS
 775        return wait_or_whine(async->pid, "child process");
 776#else
 777        void *ret = (void *)(intptr_t)(-1);
 778
 779        if (pthread_join(async->tid, &ret))
 780                error("pthread_join failed");
 781        return (int)(intptr_t)ret;
 782#endif
 783}
 784
 785const char *find_hook(const char *name)
 786{
 787        static struct strbuf path = STRBUF_INIT;
 788
 789        strbuf_reset(&path);
 790        strbuf_git_path(&path, "hooks/%s", name);
 791        if (access(path.buf, X_OK) < 0)
 792                return NULL;
 793        return path.buf;
 794}
 795
 796int run_hook_ve(const char *const *env, const char *name, va_list args)
 797{
 798        struct child_process hook = CHILD_PROCESS_INIT;
 799        const char *p;
 800
 801        p = find_hook(name);
 802        if (!p)
 803                return 0;
 804
 805        argv_array_push(&hook.args, p);
 806        while ((p = va_arg(args, const char *)))
 807                argv_array_push(&hook.args, p);
 808        hook.env = env;
 809        hook.no_stdin = 1;
 810        hook.stdout_to_stderr = 1;
 811
 812        return run_command(&hook);
 813}
 814
 815int run_hook_le(const char *const *env, const char *name, ...)
 816{
 817        va_list args;
 818        int ret;
 819
 820        va_start(args, name);
 821        ret = run_hook_ve(env, name, args);
 822        va_end(args);
 823
 824        return ret;
 825}
 826
 827int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint)
 828{
 829        cmd->out = -1;
 830        if (start_command(cmd) < 0)
 831                return -1;
 832
 833        if (strbuf_read(buf, cmd->out, hint) < 0) {
 834                close(cmd->out);
 835                finish_command(cmd); /* throw away exit code */
 836                return -1;
 837        }
 838
 839        close(cmd->out);
 840        return finish_command(cmd);
 841}