Andrew's git / gitweb.git / run-command.c
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run-command.con commit Merge branch 'jk/test-with-x' into maint (84deb3e)
   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_err = 2;
 204static int child_notifier = -1;
 205
 206static void notify_parent(void)
 207{
 208        /*
 209         * execvp failed.  If possible, we'd like to let start_command
 210         * know, so failures like ENOENT can be handled right away; but
 211         * otherwise, finish_command will still report the error.
 212         */
 213        xwrite(child_notifier, "", 1);
 214}
 215
 216static NORETURN void die_child(const char *err, va_list params)
 217{
 218        vwritef(child_err, "fatal: ", err, params);
 219        exit(128);
 220}
 221
 222static void error_child(const char *err, va_list params)
 223{
 224        vwritef(child_err, "error: ", err, params);
 225}
 226#endif
 227
 228static inline void set_cloexec(int fd)
 229{
 230        int flags = fcntl(fd, F_GETFD);
 231        if (flags >= 0)
 232                fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 233}
 234
 235static int wait_or_whine(pid_t pid, const char *argv0)
 236{
 237        int status, code = -1;
 238        pid_t waiting;
 239        int failed_errno = 0;
 240
 241        while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 242                ;       /* nothing */
 243
 244        if (waiting < 0) {
 245                failed_errno = errno;
 246                error("waitpid for %s failed: %s", argv0, strerror(errno));
 247        } else if (waiting != pid) {
 248                error("waitpid is confused (%s)", argv0);
 249        } else if (WIFSIGNALED(status)) {
 250                code = WTERMSIG(status);
 251                if (code != SIGINT && code != SIGQUIT)
 252                        error("%s died of signal %d", argv0, code);
 253                /*
 254                 * This return value is chosen so that code & 0xff
 255                 * mimics the exit code that a POSIX shell would report for
 256                 * a program that died from this signal.
 257                 */
 258                code += 128;
 259        } else if (WIFEXITED(status)) {
 260                code = WEXITSTATUS(status);
 261                /*
 262                 * Convert special exit code when execvp failed.
 263                 */
 264                if (code == 127) {
 265                        code = -1;
 266                        failed_errno = ENOENT;
 267                }
 268        } else {
 269                error("waitpid is confused (%s)", argv0);
 270        }
 271
 272        clear_child_for_cleanup(pid);
 273
 274        errno = failed_errno;
 275        return code;
 276}
 277
 278int start_command(struct child_process *cmd)
 279{
 280        int need_in, need_out, need_err;
 281        int fdin[2], fdout[2], fderr[2];
 282        int failed_errno;
 283        char *str;
 284
 285        if (!cmd->argv)
 286                cmd->argv = cmd->args.argv;
 287        if (!cmd->env)
 288                cmd->env = cmd->env_array.argv;
 289
 290        /*
 291         * In case of errors we must keep the promise to close FDs
 292         * that have been passed in via ->in and ->out.
 293         */
 294
 295        need_in = !cmd->no_stdin && cmd->in < 0;
 296        if (need_in) {
 297                if (pipe(fdin) < 0) {
 298                        failed_errno = errno;
 299                        if (cmd->out > 0)
 300                                close(cmd->out);
 301                        str = "standard input";
 302                        goto fail_pipe;
 303                }
 304                cmd->in = fdin[1];
 305        }
 306
 307        need_out = !cmd->no_stdout
 308                && !cmd->stdout_to_stderr
 309                && cmd->out < 0;
 310        if (need_out) {
 311                if (pipe(fdout) < 0) {
 312                        failed_errno = errno;
 313                        if (need_in)
 314                                close_pair(fdin);
 315                        else if (cmd->in)
 316                                close(cmd->in);
 317                        str = "standard output";
 318                        goto fail_pipe;
 319                }
 320                cmd->out = fdout[0];
 321        }
 322
 323        need_err = !cmd->no_stderr && cmd->err < 0;
 324        if (need_err) {
 325                if (pipe(fderr) < 0) {
 326                        failed_errno = errno;
 327                        if (need_in)
 328                                close_pair(fdin);
 329                        else if (cmd->in)
 330                                close(cmd->in);
 331                        if (need_out)
 332                                close_pair(fdout);
 333                        else if (cmd->out)
 334                                close(cmd->out);
 335                        str = "standard error";
 336fail_pipe:
 337                        error("cannot create %s pipe for %s: %s",
 338                                str, cmd->argv[0], strerror(failed_errno));
 339                        argv_array_clear(&cmd->args);
 340                        argv_array_clear(&cmd->env_array);
 341                        errno = failed_errno;
 342                        return -1;
 343                }
 344                cmd->err = fderr[0];
 345        }
 346
 347        trace_argv_printf(cmd->argv, "trace: run_command:");
 348        fflush(NULL);
 349
 350#ifndef GIT_WINDOWS_NATIVE
 351{
 352        int notify_pipe[2];
 353        if (pipe(notify_pipe))
 354                notify_pipe[0] = notify_pipe[1] = -1;
 355
 356        cmd->pid = fork();
 357        failed_errno = errno;
 358        if (!cmd->pid) {
 359                /*
 360                 * Redirect the channel to write syscall error messages to
 361                 * before redirecting the process's stderr so that all die()
 362                 * in subsequent call paths use the parent's stderr.
 363                 */
 364                if (cmd->no_stderr || need_err) {
 365                        child_err = dup(2);
 366                        set_cloexec(child_err);
 367                }
 368                set_die_routine(die_child);
 369                set_error_routine(error_child);
 370
 371                close(notify_pipe[0]);
 372                set_cloexec(notify_pipe[1]);
 373                child_notifier = notify_pipe[1];
 374                atexit(notify_parent);
 375
 376                if (cmd->no_stdin)
 377                        dup_devnull(0);
 378                else if (need_in) {
 379                        dup2(fdin[0], 0);
 380                        close_pair(fdin);
 381                } else if (cmd->in) {
 382                        dup2(cmd->in, 0);
 383                        close(cmd->in);
 384                }
 385
 386                if (cmd->no_stderr)
 387                        dup_devnull(2);
 388                else if (need_err) {
 389                        dup2(fderr[1], 2);
 390                        close_pair(fderr);
 391                } else if (cmd->err > 1) {
 392                        dup2(cmd->err, 2);
 393                        close(cmd->err);
 394                }
 395
 396                if (cmd->no_stdout)
 397                        dup_devnull(1);
 398                else if (cmd->stdout_to_stderr)
 399                        dup2(2, 1);
 400                else if (need_out) {
 401                        dup2(fdout[1], 1);
 402                        close_pair(fdout);
 403                } else if (cmd->out > 1) {
 404                        dup2(cmd->out, 1);
 405                        close(cmd->out);
 406                }
 407
 408                if (cmd->dir && chdir(cmd->dir))
 409                        die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 410                            cmd->dir);
 411                if (cmd->env) {
 412                        for (; *cmd->env; cmd->env++) {
 413                                if (strchr(*cmd->env, '='))
 414                                        putenv((char *)*cmd->env);
 415                                else
 416                                        unsetenv(*cmd->env);
 417                        }
 418                }
 419                if (cmd->git_cmd)
 420                        execv_git_cmd(cmd->argv);
 421                else if (cmd->use_shell)
 422                        execv_shell_cmd(cmd->argv);
 423                else
 424                        sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 425                if (errno == ENOENT) {
 426                        if (!cmd->silent_exec_failure)
 427                                error("cannot run %s: %s", cmd->argv[0],
 428                                        strerror(ENOENT));
 429                        exit(127);
 430                } else {
 431                        die_errno("cannot exec '%s'", cmd->argv[0]);
 432                }
 433        }
 434        if (cmd->pid < 0)
 435                error("cannot fork() for %s: %s", cmd->argv[0],
 436                        strerror(errno));
 437        else if (cmd->clean_on_exit)
 438                mark_child_for_cleanup(cmd->pid);
 439
 440        /*
 441         * Wait for child's execvp. If the execvp succeeds (or if fork()
 442         * failed), EOF is seen immediately by the parent. Otherwise, the
 443         * child process sends a single byte.
 444         * Note that use of this infrastructure is completely advisory,
 445         * therefore, we keep error checks minimal.
 446         */
 447        close(notify_pipe[1]);
 448        if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 449                /*
 450                 * At this point we know that fork() succeeded, but execvp()
 451                 * failed. Errors have been reported to our stderr.
 452                 */
 453                wait_or_whine(cmd->pid, cmd->argv[0]);
 454                failed_errno = errno;
 455                cmd->pid = -1;
 456        }
 457        close(notify_pipe[0]);
 458}
 459#else
 460{
 461        int fhin = 0, fhout = 1, fherr = 2;
 462        const char **sargv = cmd->argv;
 463
 464        if (cmd->no_stdin)
 465                fhin = open("/dev/null", O_RDWR);
 466        else if (need_in)
 467                fhin = dup(fdin[0]);
 468        else if (cmd->in)
 469                fhin = dup(cmd->in);
 470
 471        if (cmd->no_stderr)
 472                fherr = open("/dev/null", O_RDWR);
 473        else if (need_err)
 474                fherr = dup(fderr[1]);
 475        else if (cmd->err > 2)
 476                fherr = dup(cmd->err);
 477
 478        if (cmd->no_stdout)
 479                fhout = open("/dev/null", O_RDWR);
 480        else if (cmd->stdout_to_stderr)
 481                fhout = dup(fherr);
 482        else if (need_out)
 483                fhout = dup(fdout[1]);
 484        else if (cmd->out > 1)
 485                fhout = dup(cmd->out);
 486
 487        if (cmd->git_cmd)
 488                cmd->argv = prepare_git_cmd(cmd->argv);
 489        else if (cmd->use_shell)
 490                cmd->argv = prepare_shell_cmd(cmd->argv);
 491
 492        cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
 493                        cmd->dir, fhin, fhout, fherr);
 494        failed_errno = errno;
 495        if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 496                error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 497        if (cmd->clean_on_exit && cmd->pid >= 0)
 498                mark_child_for_cleanup(cmd->pid);
 499
 500        if (cmd->git_cmd)
 501                free(cmd->argv);
 502
 503        cmd->argv = sargv;
 504        if (fhin != 0)
 505                close(fhin);
 506        if (fhout != 1)
 507                close(fhout);
 508        if (fherr != 2)
 509                close(fherr);
 510}
 511#endif
 512
 513        if (cmd->pid < 0) {
 514                if (need_in)
 515                        close_pair(fdin);
 516                else if (cmd->in)
 517                        close(cmd->in);
 518                if (need_out)
 519                        close_pair(fdout);
 520                else if (cmd->out)
 521                        close(cmd->out);
 522                if (need_err)
 523                        close_pair(fderr);
 524                else if (cmd->err)
 525                        close(cmd->err);
 526                argv_array_clear(&cmd->args);
 527                argv_array_clear(&cmd->env_array);
 528                errno = failed_errno;
 529                return -1;
 530        }
 531
 532        if (need_in)
 533                close(fdin[0]);
 534        else if (cmd->in)
 535                close(cmd->in);
 536
 537        if (need_out)
 538                close(fdout[1]);
 539        else if (cmd->out)
 540                close(cmd->out);
 541
 542        if (need_err)
 543                close(fderr[1]);
 544        else if (cmd->err)
 545                close(cmd->err);
 546
 547        return 0;
 548}
 549
 550int finish_command(struct child_process *cmd)
 551{
 552        int ret = wait_or_whine(cmd->pid, cmd->argv[0]);
 553        argv_array_clear(&cmd->args);
 554        argv_array_clear(&cmd->env_array);
 555        return ret;
 556}
 557
 558int run_command(struct child_process *cmd)
 559{
 560        int code;
 561
 562        if (cmd->out < 0 || cmd->err < 0)
 563                die("BUG: run_command with a pipe can cause deadlock");
 564
 565        code = start_command(cmd);
 566        if (code)
 567                return code;
 568        return finish_command(cmd);
 569}
 570
 571int run_command_v_opt(const char **argv, int opt)
 572{
 573        return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
 574}
 575
 576int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 577{
 578        struct child_process cmd = CHILD_PROCESS_INIT;
 579        cmd.argv = argv;
 580        cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 581        cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 582        cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 583        cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 584        cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 585        cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 586        cmd.dir = dir;
 587        cmd.env = env;
 588        return run_command(&cmd);
 589}
 590
 591#ifndef NO_PTHREADS
 592static pthread_t main_thread;
 593static int main_thread_set;
 594static pthread_key_t async_key;
 595static pthread_key_t async_die_counter;
 596
 597static void *run_thread(void *data)
 598{
 599        struct async *async = data;
 600        intptr_t ret;
 601
 602        pthread_setspecific(async_key, async);
 603        ret = async->proc(async->proc_in, async->proc_out, async->data);
 604        return (void *)ret;
 605}
 606
 607static NORETURN void die_async(const char *err, va_list params)
 608{
 609        vreportf("fatal: ", err, params);
 610
 611        if (!pthread_equal(main_thread, pthread_self())) {
 612                struct async *async = pthread_getspecific(async_key);
 613                if (async->proc_in >= 0)
 614                        close(async->proc_in);
 615                if (async->proc_out >= 0)
 616                        close(async->proc_out);
 617                pthread_exit((void *)128);
 618        }
 619
 620        exit(128);
 621}
 622
 623static int async_die_is_recursing(void)
 624{
 625        void *ret = pthread_getspecific(async_die_counter);
 626        pthread_setspecific(async_die_counter, (void *)1);
 627        return ret != NULL;
 628}
 629
 630#else
 631
 632static struct {
 633        void (**handlers)(void);
 634        size_t nr;
 635        size_t alloc;
 636} git_atexit_hdlrs;
 637
 638static int git_atexit_installed;
 639
 640static void git_atexit_dispatch(void)
 641{
 642        size_t i;
 643
 644        for (i=git_atexit_hdlrs.nr ; i ; i--)
 645                git_atexit_hdlrs.handlers[i-1]();
 646}
 647
 648static void git_atexit_clear(void)
 649{
 650        free(git_atexit_hdlrs.handlers);
 651        memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
 652        git_atexit_installed = 0;
 653}
 654
 655#undef atexit
 656int git_atexit(void (*handler)(void))
 657{
 658        ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
 659        git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
 660        if (!git_atexit_installed) {
 661                if (atexit(&git_atexit_dispatch))
 662                        return -1;
 663                git_atexit_installed = 1;
 664        }
 665        return 0;
 666}
 667#define atexit git_atexit
 668
 669#endif
 670
 671int start_async(struct async *async)
 672{
 673        int need_in, need_out;
 674        int fdin[2], fdout[2];
 675        int proc_in, proc_out;
 676
 677        need_in = async->in < 0;
 678        if (need_in) {
 679                if (pipe(fdin) < 0) {
 680                        if (async->out > 0)
 681                                close(async->out);
 682                        return error("cannot create pipe: %s", strerror(errno));
 683                }
 684                async->in = fdin[1];
 685        }
 686
 687        need_out = async->out < 0;
 688        if (need_out) {
 689                if (pipe(fdout) < 0) {
 690                        if (need_in)
 691                                close_pair(fdin);
 692                        else if (async->in)
 693                                close(async->in);
 694                        return error("cannot create pipe: %s", strerror(errno));
 695                }
 696                async->out = fdout[0];
 697        }
 698
 699        if (need_in)
 700                proc_in = fdin[0];
 701        else if (async->in)
 702                proc_in = async->in;
 703        else
 704                proc_in = -1;
 705
 706        if (need_out)
 707                proc_out = fdout[1];
 708        else if (async->out)
 709                proc_out = async->out;
 710        else
 711                proc_out = -1;
 712
 713#ifdef NO_PTHREADS
 714        /* Flush stdio before fork() to avoid cloning buffers */
 715        fflush(NULL);
 716
 717        async->pid = fork();
 718        if (async->pid < 0) {
 719                error("fork (async) failed: %s", strerror(errno));
 720                goto error;
 721        }
 722        if (!async->pid) {
 723                if (need_in)
 724                        close(fdin[1]);
 725                if (need_out)
 726                        close(fdout[0]);
 727                git_atexit_clear();
 728                exit(!!async->proc(proc_in, proc_out, async->data));
 729        }
 730
 731        mark_child_for_cleanup(async->pid);
 732
 733        if (need_in)
 734                close(fdin[0]);
 735        else if (async->in)
 736                close(async->in);
 737
 738        if (need_out)
 739                close(fdout[1]);
 740        else if (async->out)
 741                close(async->out);
 742#else
 743        if (!main_thread_set) {
 744                /*
 745                 * We assume that the first time that start_async is called
 746                 * it is from the main thread.
 747                 */
 748                main_thread_set = 1;
 749                main_thread = pthread_self();
 750                pthread_key_create(&async_key, NULL);
 751                pthread_key_create(&async_die_counter, NULL);
 752                set_die_routine(die_async);
 753                set_die_is_recursing_routine(async_die_is_recursing);
 754        }
 755
 756        if (proc_in >= 0)
 757                set_cloexec(proc_in);
 758        if (proc_out >= 0)
 759                set_cloexec(proc_out);
 760        async->proc_in = proc_in;
 761        async->proc_out = proc_out;
 762        {
 763                int err = pthread_create(&async->tid, NULL, run_thread, async);
 764                if (err) {
 765                        error("cannot create thread: %s", strerror(err));
 766                        goto error;
 767                }
 768        }
 769#endif
 770        return 0;
 771
 772error:
 773        if (need_in)
 774                close_pair(fdin);
 775        else if (async->in)
 776                close(async->in);
 777
 778        if (need_out)
 779                close_pair(fdout);
 780        else if (async->out)
 781                close(async->out);
 782        return -1;
 783}
 784
 785int finish_async(struct async *async)
 786{
 787#ifdef NO_PTHREADS
 788        return wait_or_whine(async->pid, "child process");
 789#else
 790        void *ret = (void *)(intptr_t)(-1);
 791
 792        if (pthread_join(async->tid, &ret))
 793                error("pthread_join failed");
 794        return (int)(intptr_t)ret;
 795#endif
 796}
 797
 798const char *find_hook(const char *name)
 799{
 800        const char *path = git_path("hooks/%s", name);
 801        if (access(path, X_OK) < 0)
 802                path = NULL;
 803
 804        return path;
 805}
 806
 807int run_hook_ve(const char *const *env, const char *name, va_list args)
 808{
 809        struct child_process hook = CHILD_PROCESS_INIT;
 810        const char *p;
 811
 812        p = find_hook(name);
 813        if (!p)
 814                return 0;
 815
 816        argv_array_push(&hook.args, p);
 817        while ((p = va_arg(args, const char *)))
 818                argv_array_push(&hook.args, p);
 819        hook.env = env;
 820        hook.no_stdin = 1;
 821        hook.stdout_to_stderr = 1;
 822
 823        return run_command(&hook);
 824}
 825
 826int run_hook_le(const char *const *env, const char *name, ...)
 827{
 828        va_list args;
 829        int ret;
 830
 831        va_start(args, name);
 832        ret = run_hook_ve(env, name, args);
 833        va_end(args);
 834
 835        return ret;
 836}
 837
 838int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint)
 839{
 840        cmd->out = -1;
 841        if (start_command(cmd) < 0)
 842                return -1;
 843
 844        if (strbuf_read(buf, cmd->out, hint) < 0) {
 845                close(cmd->out);
 846                finish_command(cmd); /* throw away exit code */
 847                return -1;
 848        }
 849
 850        close(cmd->out);
 851        return finish_command(cmd);
 852}