run-command.c

   1 #include "cache.h"
   2 #include "run-command.h"
   3 #include "exec_cmd.h"
   4 #include "sigchain.h"
   5 #include "argv-array.h"
   6
   7 #ifndef SHELL_PATH
   8 # define SHELL_PATH "/bin/sh"
   9 #endif
  10
  11 struct child_to_clean {
  12         pid_t pid;
  13         struct child_to_clean *next;
  14 };
  15 static struct child_to_clean *children_to_clean;
  16 static int installed_child_cleanup_handler;
  17
  18 static void cleanup_children(int sig)
  19 {
  20         while (children_to_clean) {
  21                 struct child_to_clean *p = children_to_clean;
  22                 children_to_clean = p->next;
  23                 kill(p->pid, sig);
  24                 free(p);
  25         }
  26 }
  27
  28 static void cleanup_children_on_signal(int sig)
  29 {
  30         cleanup_children(sig);
  31         sigchain_pop(sig);
  32         raise(sig);
  33 }
  34
  35 static void cleanup_children_on_exit(void)
  36 {
  37         cleanup_children(SIGTERM);
  38 }
  39
  40 static void mark_child_for_cleanup(pid_t pid)
  41 {
  42         struct child_to_clean *p = xmalloc(sizeof(*p));
  43         p->pid = pid;
  44         p->next = children_to_clean;
  45         children_to_clean = p;
  46
  47         if (!installed_child_cleanup_handler) {
  48                 atexit(cleanup_children_on_exit);
  49                 sigchain_push_common(cleanup_children_on_signal);
  50                 installed_child_cleanup_handler = 1;
  51         }
  52 }
  53
  54 static void clear_child_for_cleanup(pid_t pid)
  55 {
  56         struct child_to_clean **pp;
  57
  58         for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
  59                 struct child_to_clean *clean_me = *pp;
  60
  61                 if (clean_me->pid == pid) {
  62                         *pp = clean_me->next;
  63                         free(clean_me);
  64                         return;
  65                 }
  66         }
  67 }
  68
  69 static inline void close_pair(int fd[2])
  70 {
  71         close(fd[0]);
  72         close(fd[1]);
  73 }
  74
  75 #ifndef WIN32
  76 static inline void dup_devnull(int to)
  77 {
  78         int fd = open("/dev/null", O_RDWR);
  79         dup2(fd, to);
  80         close(fd);
  81 }
  82 #endif
  83
  84 static char *locate_in_PATH(const char *file)
  85 {
  86         const char *p = getenv("PATH");
  87         struct strbuf buf = STRBUF_INIT;
  88
  89         if (!p || !*p)
  90                 return NULL;
  91
  92         while (1) {
  93                 const char *end = strchrnul(p, ':');
  94
  95                 strbuf_reset(&buf);
  96
  97                 /* POSIX specifies an empty entry as the current directory. */
  98                 if (end != p) {
  99                         strbuf_add(&buf, p, end - p);
 100                         strbuf_addch(&buf, '/');
 101                 }
 102                 strbuf_addstr(&buf, file);
 103
 104                 if (!access(buf.buf, F_OK))
 105                         return strbuf_detach(&buf, NULL);
 106
 107                 if (!*end)
 108                         break;
 109                 p = end + 1;
 110         }
 111
 112         strbuf_release(&buf);
 113         return NULL;
 114 }
 115
 116 static int exists_in_PATH(const char *file)
 117 {
 118         char *r = locate_in_PATH(file);
 119         free(r);
 120         return r != NULL;
 121 }
 122
 123 int sane_execvp(const char *file, char * const argv[])
 124 {
 125         if (!execvp(file, argv))
 126                 return 0; /* cannot happen ;-) */
 127
 128         /*
 129          * When a command can't be found because one of the directories
 130          * listed in $PATH is unsearchable, execvp reports EACCES, but
 131          * careful usability testing (read: analysis of occasional bug
 132          * reports) reveals that "No such file or directory" is more
 133          * intuitive.
 134          *
 135          * We avoid commands with "/", because execvp will not do $PATH
 136          * lookups in that case.
 137          *
 138          * The reassignment of EACCES to errno looks like a no-op below,
 139          * but we need to protect against exists_in_PATH overwriting errno.
 140          */
 141         if (errno == EACCES && !strchr(file, '/'))
 142                 errno = exists_in_PATH(file) ? EACCES : ENOENT;
 143         else if (errno == ENOTDIR && !strchr(file, '/'))
 144                 errno = ENOENT;
 145         return -1;
 146 }
 147
 148 static const char **prepare_shell_cmd(const char **argv)
 149 {
 150         int argc, nargc = 0;
 151         const char **nargv;
 152
 153         for (argc = 0; argv[argc]; argc++)
 154                 ; /* just counting */
 155         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
 156         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
 157
 158         if (argc < 1)
 159                 die("BUG: shell command is empty");
 160
 161         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 162 #ifndef WIN32
 163                 nargv[nargc++] = SHELL_PATH;
 164 #else
 165                 nargv[nargc++] = "sh";
 166 #endif
 167                 nargv[nargc++] = "-c";
 168
 169                 if (argc < 2)
 170                         nargv[nargc++] = argv[0];
 171                 else {
 172                         struct strbuf arg0 = STRBUF_INIT;
 173                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 174                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
 175                 }
 176         }
 177
 178         for (argc = 0; argv[argc]; argc++)
 179                 nargv[nargc++] = argv[argc];
 180         nargv[nargc] = NULL;
 181
 182         return nargv;
 183 }
 184
 185 #ifndef WIN32
 186 static int execv_shell_cmd(const char **argv)
 187 {
 188         const char **nargv = prepare_shell_cmd(argv);
 189         trace_argv_printf(nargv, "trace: exec:");
 190         sane_execvp(nargv[0], (char **)nargv);
 191         free(nargv);
 192         return -1;
 193 }
 194 #endif
 195
 196 #ifndef WIN32
 197 static int child_err = 2;
 198 static int child_notifier = -1;
 199
 200 static void notify_parent(void)
 201 {
 202         /*
 203          * execvp failed.  If possible, we'd like to let start_command
 204          * know, so failures like ENOENT can be handled right away; but
 205          * otherwise, finish_command will still report the error.
 206          */
 207         xwrite(child_notifier, "", 1);
 208 }
 209
 210 static NORETURN void die_child(const char *err, va_list params)
 211 {
 212         vwritef(child_err, "fatal: ", err, params);
 213         exit(128);
 214 }
 215
 216 static void error_child(const char *err, va_list params)
 217 {
 218         vwritef(child_err, "error: ", err, params);
 219 }
 220 #endif
 221
 222 static inline void set_cloexec(int fd)
 223 {
 224         int flags = fcntl(fd, F_GETFD);
 225         if (flags >= 0)
 226                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 227 }
 228
 229 static int wait_or_whine(pid_t pid, const char *argv0)
 230 {
 231         int status, code = -1;
 232         pid_t waiting;
 233         int failed_errno = 0;
 234
 235         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 236                 ;       /* nothing */
 237
 238         if (waiting < 0) {
 239                 failed_errno = errno;
 240                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 241         } else if (waiting != pid) {
 242                 error("waitpid is confused (%s)", argv0);
 243         } else if (WIFSIGNALED(status)) {
 244                 code = WTERMSIG(status);
 245                 if (code != SIGINT && code != SIGQUIT)
 246                         error("%s died of signal %d", argv0, code);
 247                 /*
 248                  * This return value is chosen so that code & 0xff
 249                  * mimics the exit code that a POSIX shell would report for
 250                  * a program that died from this signal.
 251                  */
 252                 code += 128;
 253         } else if (WIFEXITED(status)) {
 254                 code = WEXITSTATUS(status);
 255                 /*
 256                  * Convert special exit code when execvp failed.
 257                  */
 258                 if (code == 127) {
 259                         code = -1;
 260                         failed_errno = ENOENT;
 261                 }
 262         } else {
 263                 error("waitpid is confused (%s)", argv0);
 264         }
 265
 266         clear_child_for_cleanup(pid);
 267
 268         errno = failed_errno;
 269         return code;
 270 }
 271
 272 int start_command(struct child_process *cmd)
 273 {
 274         int need_in, need_out, need_err;
 275         int fdin[2], fdout[2], fderr[2];
 276         int failed_errno = failed_errno;
 277         char *str;
 278
 279         /*
 280          * In case of errors we must keep the promise to close FDs
 281          * that have been passed in via ->in and ->out.
 282          */
 283
 284         need_in = !cmd->no_stdin && cmd->in < 0;
 285         if (need_in) {
 286                 if (pipe(fdin) < 0) {
 287                         failed_errno = errno;
 288                         if (cmd->out > 0)
 289                                 close(cmd->out);
 290                         str = "standard input";
 291                         goto fail_pipe;
 292                 }
 293                 cmd->in = fdin[1];
 294         }
 295
 296         need_out = !cmd->no_stdout
 297                 && !cmd->stdout_to_stderr
 298                 && cmd->out < 0;
 299         if (need_out) {
 300                 if (pipe(fdout) < 0) {
 301                         failed_errno = errno;
 302                         if (need_in)
 303                                 close_pair(fdin);
 304                         else if (cmd->in)
 305                                 close(cmd->in);
 306                         str = "standard output";
 307                         goto fail_pipe;
 308                 }
 309                 cmd->out = fdout[0];
 310         }
 311
 312         need_err = !cmd->no_stderr && cmd->err < 0;
 313         if (need_err) {
 314                 if (pipe(fderr) < 0) {
 315                         failed_errno = errno;
 316                         if (need_in)
 317                                 close_pair(fdin);
 318                         else if (cmd->in)
 319                                 close(cmd->in);
 320                         if (need_out)
 321                                 close_pair(fdout);
 322                         else if (cmd->out)
 323                                 close(cmd->out);
 324                         str = "standard error";
 325 fail_pipe:
 326                         error("cannot create %s pipe for %s: %s",
 327                                 str, cmd->argv[0], strerror(failed_errno));
 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 WIN32
 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         if (!cmd->pid) {
 345                 /*
 346                  * Redirect the channel to write syscall error messages to
 347                  * before redirecting the process's stderr so that all die()
 348                  * in subsequent call paths use the parent's stderr.
 349                  */
 350                 if (cmd->no_stderr || need_err) {
 351                         child_err = dup(2);
 352                         set_cloexec(child_err);
 353                 }
 354                 set_die_routine(die_child);
 355                 set_error_routine(error_child);
 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                 }
 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(failed_errno = 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 }
 447 #else
 448 {
 449         int fhin = 0, fhout = 1, fherr = 2;
 450         const char **sargv = cmd->argv;
 451         char **env = environ;
 452
 453         if (cmd->no_stdin)
 454                 fhin = open("/dev/null", O_RDWR);
 455         else if (need_in)
 456                 fhin = dup(fdin[0]);
 457         else if (cmd->in)
 458                 fhin = dup(cmd->in);
 459
 460         if (cmd->no_stderr)
 461                 fherr = open("/dev/null", O_RDWR);
 462         else if (need_err)
 463                 fherr = dup(fderr[1]);
 464         else if (cmd->err > 2)
 465                 fherr = dup(cmd->err);
 466
 467         if (cmd->no_stdout)
 468                 fhout = open("/dev/null", O_RDWR);
 469         else if (cmd->stdout_to_stderr)
 470                 fhout = dup(fherr);
 471         else if (need_out)
 472                 fhout = dup(fdout[1]);
 473         else if (cmd->out > 1)
 474                 fhout = dup(cmd->out);
 475
 476         if (cmd->env)
 477                 env = make_augmented_environ(cmd->env);
 478
 479         if (cmd->git_cmd) {
 480                 cmd->argv = prepare_git_cmd(cmd->argv);
 481         } else if (cmd->use_shell) {
 482                 cmd->argv = prepare_shell_cmd(cmd->argv);
 483         }
 484
 485         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 486                                   fhin, fhout, fherr);
 487         failed_errno = errno;
 488         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 489                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 490         if (cmd->clean_on_exit && cmd->pid >= 0)
 491                 mark_child_for_cleanup(cmd->pid);
 492
 493         if (cmd->env)
 494                 free_environ(env);
 495         if (cmd->git_cmd)
 496                 free(cmd->argv);
 497
 498         cmd->argv = sargv;
 499         if (fhin != 0)
 500                 close(fhin);
 501         if (fhout != 1)
 502                 close(fhout);
 503         if (fherr != 2)
 504                 close(fherr);
 505 }
 506 #endif
 507
 508         if (cmd->pid < 0) {
 509                 if (need_in)
 510                         close_pair(fdin);
 511                 else if (cmd->in)
 512                         close(cmd->in);
 513                 if (need_out)
 514                         close_pair(fdout);
 515                 else if (cmd->out)
 516                         close(cmd->out);
 517                 if (need_err)
 518                         close_pair(fderr);
 519                 else if (cmd->err)
 520                         close(cmd->err);
 521                 errno = failed_errno;
 522                 return -1;
 523         }
 524
 525         if (need_in)
 526                 close(fdin[0]);
 527         else if (cmd->in)
 528                 close(cmd->in);
 529
 530         if (need_out)
 531                 close(fdout[1]);
 532         else if (cmd->out)
 533                 close(cmd->out);
 534
 535         if (need_err)
 536                 close(fderr[1]);
 537         else if (cmd->err)
 538                 close(cmd->err);
 539
 540         return 0;
 541 }
 542
 543 int finish_command(struct child_process *cmd)
 544 {
 545         return wait_or_whine(cmd->pid, cmd->argv[0]);
 546 }
 547
 548 int run_command(struct child_process *cmd)
 549 {
 550         int code = start_command(cmd);
 551         if (code)
 552                 return code;
 553         return finish_command(cmd);
 554 }
 555
 556 static void prepare_run_command_v_opt(struct child_process *cmd,
 557                                       const char **argv,
 558                                       int opt)
 559 {
 560         memset(cmd, 0, sizeof(*cmd));
 561         cmd->argv = argv;
 562         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 563         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 564         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 565         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 566         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 567         cmd->clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 568 }
 569
 570 int run_command_v_opt(const char **argv, int opt)
 571 {
 572         struct child_process cmd;
 573         prepare_run_command_v_opt(&cmd, argv, opt);
 574         return run_command(&cmd);
 575 }
 576
 577 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 578 {
 579         struct child_process cmd;
 580         prepare_run_command_v_opt(&cmd, argv, opt);
 581         cmd.dir = dir;
 582         cmd.env = env;
 583         return run_command(&cmd);
 584 }
 585
 586 #ifndef NO_PTHREADS
 587 static pthread_t main_thread;
 588 static int main_thread_set;
 589 static pthread_key_t async_key;
 590
 591 static void *run_thread(void *data)
 592 {
 593         struct async *async = data;
 594         intptr_t ret;
 595
 596         pthread_setspecific(async_key, async);
 597         ret = async->proc(async->proc_in, async->proc_out, async->data);
 598         return (void *)ret;
 599 }
 600
 601 static NORETURN void die_async(const char *err, va_list params)
 602 {
 603         vreportf("fatal: ", err, params);
 604
 605         if (!pthread_equal(main_thread, pthread_self())) {
 606                 struct async *async = pthread_getspecific(async_key);
 607                 if (async->proc_in >= 0)
 608                         close(async->proc_in);
 609                 if (async->proc_out >= 0)
 610                         close(async->proc_out);
 611                 pthread_exit((void *)128);
 612         }
 613
 614         exit(128);
 615 }
 616 #endif
 617
 618 int start_async(struct async *async)
 619 {
 620         int need_in, need_out;
 621         int fdin[2], fdout[2];
 622         int proc_in, proc_out;
 623
 624         need_in = async->in < 0;
 625         if (need_in) {
 626                 if (pipe(fdin) < 0) {
 627                         if (async->out > 0)
 628                                 close(async->out);
 629                         return error("cannot create pipe: %s", strerror(errno));
 630                 }
 631                 async->in = fdin[1];
 632         }
 633
 634         need_out = async->out < 0;
 635         if (need_out) {
 636                 if (pipe(fdout) < 0) {
 637                         if (need_in)
 638                                 close_pair(fdin);
 639                         else if (async->in)
 640                                 close(async->in);
 641                         return error("cannot create pipe: %s", strerror(errno));
 642                 }
 643                 async->out = fdout[0];
 644         }
 645
 646         if (need_in)
 647                 proc_in = fdin[0];
 648         else if (async->in)
 649                 proc_in = async->in;
 650         else
 651                 proc_in = -1;
 652
 653         if (need_out)
 654                 proc_out = fdout[1];
 655         else if (async->out)
 656                 proc_out = async->out;
 657         else
 658                 proc_out = -1;
 659
 660 #ifdef NO_PTHREADS
 661         /* Flush stdio before fork() to avoid cloning buffers */
 662         fflush(NULL);
 663
 664         async->pid = fork();
 665         if (async->pid < 0) {
 666                 error("fork (async) failed: %s", strerror(errno));
 667                 goto error;
 668         }
 669         if (!async->pid) {
 670                 if (need_in)
 671                         close(fdin[1]);
 672                 if (need_out)
 673                         close(fdout[0]);
 674                 exit(!!async->proc(proc_in, proc_out, async->data));
 675         }
 676
 677         mark_child_for_cleanup(async->pid);
 678
 679         if (need_in)
 680                 close(fdin[0]);
 681         else if (async->in)
 682                 close(async->in);
 683
 684         if (need_out)
 685                 close(fdout[1]);
 686         else if (async->out)
 687                 close(async->out);
 688 #else
 689         if (!main_thread_set) {
 690                 /*
 691                  * We assume that the first time that start_async is called
 692                  * it is from the main thread.
 693                  */
 694                 main_thread_set = 1;
 695                 main_thread = pthread_self();
 696                 pthread_key_create(&async_key, NULL);
 697                 set_die_routine(die_async);
 698         }
 699
 700         if (proc_in >= 0)
 701                 set_cloexec(proc_in);
 702         if (proc_out >= 0)
 703                 set_cloexec(proc_out);
 704         async->proc_in = proc_in;
 705         async->proc_out = proc_out;
 706         {
 707                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 708                 if (err) {
 709                         error("cannot create thread: %s", strerror(err));
 710                         goto error;
 711                 }
 712         }
 713 #endif
 714         return 0;
 715
 716 error:
 717         if (need_in)
 718                 close_pair(fdin);
 719         else if (async->in)
 720                 close(async->in);
 721
 722         if (need_out)
 723                 close_pair(fdout);
 724         else if (async->out)
 725                 close(async->out);
 726         return -1;
 727 }
 728
 729 int finish_async(struct async *async)
 730 {
 731 #ifdef NO_PTHREADS
 732         return wait_or_whine(async->pid, "child process");
 733 #else
 734         void *ret = (void *)(intptr_t)(-1);
 735
 736         if (pthread_join(async->tid, &ret))
 737                 error("pthread_join failed");
 738         return (int)(intptr_t)ret;
 739 #endif
 740 }
 741
 742 char *find_hook(const char *name)
 743 {
 744         char *path = git_path("hooks/%s", name);
 745         if (access(path, X_OK) < 0)
 746                 path = NULL;
 747
 748         return path;
 749 }
 750
 751 int run_hook(const char *index_file, const char *name, ...)
 752 {
 753         struct child_process hook;
 754         struct argv_array argv = ARGV_ARRAY_INIT;
 755         const char *p, *env[2];
 756         char index[PATH_MAX];
 757         va_list args;
 758         int ret;
 759
 760         p = find_hook(name);
 761         if (!p)
 762                 return 0;
 763
 764         argv_array_push(&argv, p);
 765
 766         va_start(args, name);
 767         while ((p = va_arg(args, const char *)))
 768                 argv_array_push(&argv, p);
 769         va_end(args);
 770
 771         memset(&hook, 0, sizeof(hook));
 772         hook.argv = argv.argv;
 773         hook.no_stdin = 1;
 774         hook.stdout_to_stderr = 1;
 775         if (index_file) {
 776                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 777                 env[0] = index;
 778                 env[1] = NULL;
 779                 hook.env = env;
 780         }
 781
 782         ret = run_command(&hook);
 783         argv_array_clear(&argv);
 784         return ret;
 785 }