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 **last, *p;
  57
  58         last = &children_to_clean;
  59         for (p = children_to_clean; p; p = p->next) {
  60                 if (p->pid == pid) {
  61                         *last = p->next;
  62                         free(p);
  63                         return;
  64                 }
  65         }
  66 }
  67
  68 static inline void close_pair(int fd[2])
  69 {
  70         close(fd[0]);
  71         close(fd[1]);
  72 }
  73
  74 #ifndef WIN32
  75 static inline void dup_devnull(int to)
  76 {
  77         int fd = open("/dev/null", O_RDWR);
  78         dup2(fd, to);
  79         close(fd);
  80 }
  81 #endif
  82
  83 static char *locate_in_PATH(const char *file)
  84 {
  85         const char *p = getenv("PATH");
  86         struct strbuf buf = STRBUF_INIT;
  87
  88         if (!p || !*p)
  89                 return NULL;
  90
  91         while (1) {
  92                 const char *end = strchrnul(p, ':');
  93
  94                 strbuf_reset(&buf);
  95
  96                 /* POSIX specifies an empty entry as the current directory. */
  97                 if (end != p) {
  98                         strbuf_add(&buf, p, end - p);
  99                         strbuf_addch(&buf, '/');
 100                 }
 101                 strbuf_addstr(&buf, file);
 102
 103                 if (!access(buf.buf, F_OK))
 104                         return strbuf_detach(&buf, NULL);
 105
 106                 if (!*end)
 107                         break;
 108                 p = end + 1;
 109         }
 110
 111         strbuf_release(&buf);
 112         return NULL;
 113 }
 114
 115 static int exists_in_PATH(const char *file)
 116 {
 117         char *r = locate_in_PATH(file);
 118         free(r);
 119         return r != NULL;
 120 }
 121
 122 int sane_execvp(const char *file, char * const argv[])
 123 {
 124         if (!execvp(file, argv))
 125                 return 0; /* cannot happen ;-) */
 126
 127         /*
 128          * When a command can't be found because one of the directories
 129          * listed in $PATH is unsearchable, execvp reports EACCES, but
 130          * careful usability testing (read: analysis of occasional bug
 131          * reports) reveals that "No such file or directory" is more
 132          * intuitive.
 133          *
 134          * We avoid commands with "/", because execvp will not do $PATH
 135          * lookups in that case.
 136          *
 137          * The reassignment of EACCES to errno looks like a no-op below,
 138          * but we need to protect against exists_in_PATH overwriting errno.
 139          */
 140         if (errno == EACCES && !strchr(file, '/'))
 141                 errno = exists_in_PATH(file) ? EACCES : ENOENT;
 142         return -1;
 143 }
 144
 145 static const char **prepare_shell_cmd(const char **argv)
 146 {
 147         int argc, nargc = 0;
 148         const char **nargv;
 149
 150         for (argc = 0; argv[argc]; argc++)
 151                 ; /* just counting */
 152         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
 153         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
 154
 155         if (argc < 1)
 156                 die("BUG: shell command is empty");
 157
 158         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 159 #ifndef WIN32
 160                 nargv[nargc++] = SHELL_PATH;
 161 #else
 162                 nargv[nargc++] = "sh";
 163 #endif
 164                 nargv[nargc++] = "-c";
 165
 166                 if (argc < 2)
 167                         nargv[nargc++] = argv[0];
 168                 else {
 169                         struct strbuf arg0 = STRBUF_INIT;
 170                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 171                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
 172                 }
 173         }
 174
 175         for (argc = 0; argv[argc]; argc++)
 176                 nargv[nargc++] = argv[argc];
 177         nargv[nargc] = NULL;
 178
 179         return nargv;
 180 }
 181
 182 #ifndef WIN32
 183 static int execv_shell_cmd(const char **argv)
 184 {
 185         const char **nargv = prepare_shell_cmd(argv);
 186         trace_argv_printf(nargv, "trace: exec:");
 187         sane_execvp(nargv[0], (char **)nargv);
 188         free(nargv);
 189         return -1;
 190 }
 191 #endif
 192
 193 #ifndef WIN32
 194 static int child_err = 2;
 195 static int child_notifier = -1;
 196
 197 static void notify_parent(void)
 198 {
 199         /*
 200          * execvp failed.  If possible, we'd like to let start_command
 201          * know, so failures like ENOENT can be handled right away; but
 202          * otherwise, finish_command will still report the error.
 203          */
 204         xwrite(child_notifier, "", 1);
 205 }
 206
 207 static NORETURN void die_child(const char *err, va_list params)
 208 {
 209         vwritef(child_err, "fatal: ", err, params);
 210         exit(128);
 211 }
 212
 213 static void error_child(const char *err, va_list params)
 214 {
 215         vwritef(child_err, "error: ", err, params);
 216 }
 217 #endif
 218
 219 static inline void set_cloexec(int fd)
 220 {
 221         int flags = fcntl(fd, F_GETFD);
 222         if (flags >= 0)
 223                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 224 }
 225
 226 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 227 {
 228         int status, code = -1;
 229         pid_t waiting;
 230         int failed_errno = 0;
 231
 232         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 233                 ;       /* nothing */
 234
 235         if (waiting < 0) {
 236                 failed_errno = errno;
 237                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 238         } else if (waiting != pid) {
 239                 error("waitpid is confused (%s)", argv0);
 240         } else if (WIFSIGNALED(status)) {
 241                 code = WTERMSIG(status);
 242                 error("%s died of signal %d", argv0, code);
 243                 /*
 244                  * This return value is chosen so that code & 0xff
 245                  * mimics the exit code that a POSIX shell would report for
 246                  * a program that died from this signal.
 247                  */
 248                 code -= 128;
 249         } else if (WIFEXITED(status)) {
 250                 code = WEXITSTATUS(status);
 251                 /*
 252                  * Convert special exit code when execvp failed.
 253                  */
 254                 if (code == 127) {
 255                         code = -1;
 256                         failed_errno = ENOENT;
 257                 }
 258         } else {
 259                 error("waitpid is confused (%s)", argv0);
 260         }
 261
 262         clear_child_for_cleanup(pid);
 263
 264         errno = failed_errno;
 265         return code;
 266 }
 267
 268 int start_command(struct child_process *cmd)
 269 {
 270         int need_in, need_out, need_err;
 271         int fdin[2], fdout[2], fderr[2];
 272         int failed_errno = failed_errno;
 273
 274         /*
 275          * In case of errors we must keep the promise to close FDs
 276          * that have been passed in via ->in and ->out.
 277          */
 278
 279         need_in = !cmd->no_stdin && cmd->in < 0;
 280         if (need_in) {
 281                 if (pipe(fdin) < 0) {
 282                         failed_errno = errno;
 283                         if (cmd->out > 0)
 284                                 close(cmd->out);
 285                         goto fail_pipe;
 286                 }
 287                 cmd->in = fdin[1];
 288         }
 289
 290         need_out = !cmd->no_stdout
 291                 && !cmd->stdout_to_stderr
 292                 && cmd->out < 0;
 293         if (need_out) {
 294                 if (pipe(fdout) < 0) {
 295                         failed_errno = errno;
 296                         if (need_in)
 297                                 close_pair(fdin);
 298                         else if (cmd->in)
 299                                 close(cmd->in);
 300                         goto fail_pipe;
 301                 }
 302                 cmd->out = fdout[0];
 303         }
 304
 305         need_err = !cmd->no_stderr && cmd->err < 0;
 306         if (need_err) {
 307                 if (pipe(fderr) < 0) {
 308                         failed_errno = errno;
 309                         if (need_in)
 310                                 close_pair(fdin);
 311                         else if (cmd->in)
 312                                 close(cmd->in);
 313                         if (need_out)
 314                                 close_pair(fdout);
 315                         else if (cmd->out)
 316                                 close(cmd->out);
 317 fail_pipe:
 318                         error("cannot create pipe for %s: %s",
 319                                 cmd->argv[0], strerror(failed_errno));
 320                         errno = failed_errno;
 321                         return -1;
 322                 }
 323                 cmd->err = fderr[0];
 324         }
 325
 326         trace_argv_printf(cmd->argv, "trace: run_command:");
 327         fflush(NULL);
 328
 329 #ifndef WIN32
 330 {
 331         int notify_pipe[2];
 332         if (pipe(notify_pipe))
 333                 notify_pipe[0] = notify_pipe[1] = -1;
 334
 335         cmd->pid = fork();
 336         if (!cmd->pid) {
 337                 /*
 338                  * Redirect the channel to write syscall error messages to
 339                  * before redirecting the process's stderr so that all die()
 340                  * in subsequent call paths use the parent's stderr.
 341                  */
 342                 if (cmd->no_stderr || need_err) {
 343                         child_err = dup(2);
 344                         set_cloexec(child_err);
 345                 }
 346                 set_die_routine(die_child);
 347                 set_error_routine(error_child);
 348
 349                 close(notify_pipe[0]);
 350                 set_cloexec(notify_pipe[1]);
 351                 child_notifier = notify_pipe[1];
 352                 atexit(notify_parent);
 353
 354                 if (cmd->no_stdin)
 355                         dup_devnull(0);
 356                 else if (need_in) {
 357                         dup2(fdin[0], 0);
 358                         close_pair(fdin);
 359                 } else if (cmd->in) {
 360                         dup2(cmd->in, 0);
 361                         close(cmd->in);
 362                 }
 363
 364                 if (cmd->no_stderr)
 365                         dup_devnull(2);
 366                 else if (need_err) {
 367                         dup2(fderr[1], 2);
 368                         close_pair(fderr);
 369                 } else if (cmd->err > 1) {
 370                         dup2(cmd->err, 2);
 371                         close(cmd->err);
 372                 }
 373
 374                 if (cmd->no_stdout)
 375                         dup_devnull(1);
 376                 else if (cmd->stdout_to_stderr)
 377                         dup2(2, 1);
 378                 else if (need_out) {
 379                         dup2(fdout[1], 1);
 380                         close_pair(fdout);
 381                 } else if (cmd->out > 1) {
 382                         dup2(cmd->out, 1);
 383                         close(cmd->out);
 384                 }
 385
 386                 if (cmd->dir && chdir(cmd->dir))
 387                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 388                             cmd->dir);
 389                 if (cmd->env) {
 390                         for (; *cmd->env; cmd->env++) {
 391                                 if (strchr(*cmd->env, '='))
 392                                         putenv((char *)*cmd->env);
 393                                 else
 394                                         unsetenv(*cmd->env);
 395                         }
 396                 }
 397                 if (cmd->preexec_cb) {
 398                         /*
 399                          * We cannot predict what the pre-exec callback does.
 400                          * Forgo parent notification.
 401                          */
 402                         close(child_notifier);
 403                         child_notifier = -1;
 404
 405                         cmd->preexec_cb();
 406                 }
 407                 if (cmd->git_cmd) {
 408                         execv_git_cmd(cmd->argv);
 409                 } else if (cmd->use_shell) {
 410                         execv_shell_cmd(cmd->argv);
 411                 } else {
 412                         sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 413                 }
 414                 if (errno == ENOENT) {
 415                         if (!cmd->silent_exec_failure)
 416                                 error("cannot run %s: %s", cmd->argv[0],
 417                                         strerror(ENOENT));
 418                         exit(127);
 419                 } else {
 420                         die_errno("cannot exec '%s'", cmd->argv[0]);
 421                 }
 422         }
 423         if (cmd->pid < 0)
 424                 error("cannot fork() for %s: %s", cmd->argv[0],
 425                         strerror(failed_errno = errno));
 426         else if (cmd->clean_on_exit)
 427                 mark_child_for_cleanup(cmd->pid);
 428
 429         /*
 430          * Wait for child's execvp. If the execvp succeeds (or if fork()
 431          * failed), EOF is seen immediately by the parent. Otherwise, the
 432          * child process sends a single byte.
 433          * Note that use of this infrastructure is completely advisory,
 434          * therefore, we keep error checks minimal.
 435          */
 436         close(notify_pipe[1]);
 437         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 438                 /*
 439                  * At this point we know that fork() succeeded, but execvp()
 440                  * failed. Errors have been reported to our stderr.
 441                  */
 442                 wait_or_whine(cmd->pid, cmd->argv[0],
 443                               cmd->silent_exec_failure);
 444                 failed_errno = errno;
 445                 cmd->pid = -1;
 446         }
 447         close(notify_pipe[0]);
 448
 449 }
 450 #else
 451 {
 452         int fhin = 0, fhout = 1, fherr = 2;
 453         const char **sargv = cmd->argv;
 454
 455         if (cmd->no_stdin)
 456                 fhin = open("/dev/null", O_RDWR);
 457         else if (need_in)
 458                 fhin = dup(fdin[0]);
 459         else if (cmd->in)
 460                 fhin = dup(cmd->in);
 461
 462         if (cmd->no_stderr)
 463                 fherr = open("/dev/null", O_RDWR);
 464         else if (need_err)
 465                 fherr = dup(fderr[1]);
 466         else if (cmd->err > 2)
 467                 fherr = dup(cmd->err);
 468
 469         if (cmd->no_stdout)
 470                 fhout = open("/dev/null", O_RDWR);
 471         else if (cmd->stdout_to_stderr)
 472                 fhout = dup(fherr);
 473         else if (need_out)
 474                 fhout = dup(fdout[1]);
 475         else if (cmd->out > 1)
 476                 fhout = dup(cmd->out);
 477
 478         if (cmd->git_cmd) {
 479                 cmd->argv = prepare_git_cmd(cmd->argv);
 480         } else if (cmd->use_shell) {
 481                 cmd->argv = prepare_shell_cmd(cmd->argv);
 482         }
 483
 484         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
 485                         cmd->dir, fhin, fhout, fherr);
 486         failed_errno = errno;
 487         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 488                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 489         if (cmd->clean_on_exit && cmd->pid >= 0)
 490                 mark_child_for_cleanup(cmd->pid);
 491
 492         if (cmd->git_cmd)
 493                 free(cmd->argv);
 494
 495         cmd->argv = sargv;
 496         if (fhin != 0)
 497                 close(fhin);
 498         if (fhout != 1)
 499                 close(fhout);
 500         if (fherr != 2)
 501                 close(fherr);
 502 }
 503 #endif
 504
 505         if (cmd->pid < 0) {
 506                 if (need_in)
 507                         close_pair(fdin);
 508                 else if (cmd->in)
 509                         close(cmd->in);
 510                 if (need_out)
 511                         close_pair(fdout);
 512                 else if (cmd->out)
 513                         close(cmd->out);
 514                 if (need_err)
 515                         close_pair(fderr);
 516                 else if (cmd->err)
 517                         close(cmd->err);
 518                 errno = failed_errno;
 519                 return -1;
 520         }
 521
 522         if (need_in)
 523                 close(fdin[0]);
 524         else if (cmd->in)
 525                 close(cmd->in);
 526
 527         if (need_out)
 528                 close(fdout[1]);
 529         else if (cmd->out)
 530                 close(cmd->out);
 531
 532         if (need_err)
 533                 close(fderr[1]);
 534         else if (cmd->err)
 535                 close(cmd->err);
 536
 537         return 0;
 538 }
 539
 540 int finish_command(struct child_process *cmd)
 541 {
 542         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 543 }
 544
 545 int run_command(struct child_process *cmd)
 546 {
 547         int code = start_command(cmd);
 548         if (code)
 549                 return code;
 550         return finish_command(cmd);
 551 }
 552
 553 static void prepare_run_command_v_opt(struct child_process *cmd,
 554                                       const char **argv,
 555                                       int opt)
 556 {
 557         memset(cmd, 0, sizeof(*cmd));
 558         cmd->argv = argv;
 559         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 560         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 561         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 562         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 563         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 564         cmd->clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 565 }
 566
 567 int run_command_v_opt(const char **argv, int opt)
 568 {
 569         struct child_process cmd;
 570         prepare_run_command_v_opt(&cmd, argv, opt);
 571         return run_command(&cmd);
 572 }
 573
 574 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 575 {
 576         struct child_process cmd;
 577         prepare_run_command_v_opt(&cmd, argv, opt);
 578         cmd.dir = dir;
 579         cmd.env = env;
 580         return run_command(&cmd);
 581 }
 582
 583 #ifndef NO_PTHREADS
 584 static pthread_t main_thread;
 585 static int main_thread_set;
 586 static pthread_key_t async_key;
 587
 588 static void *run_thread(void *data)
 589 {
 590         struct async *async = data;
 591         intptr_t ret;
 592
 593         pthread_setspecific(async_key, async);
 594         ret = async->proc(async->proc_in, async->proc_out, async->data);
 595         return (void *)ret;
 596 }
 597
 598 static NORETURN void die_async(const char *err, va_list params)
 599 {
 600         vreportf("fatal: ", err, params);
 601
 602         if (!pthread_equal(main_thread, pthread_self())) {
 603                 struct async *async = pthread_getspecific(async_key);
 604                 if (async->proc_in >= 0)
 605                         close(async->proc_in);
 606                 if (async->proc_out >= 0)
 607                         close(async->proc_out);
 608                 pthread_exit((void *)128);
 609         }
 610
 611         exit(128);
 612 }
 613 #endif
 614
 615 int start_async(struct async *async)
 616 {
 617         int need_in, need_out;
 618         int fdin[2], fdout[2];
 619         int proc_in, proc_out;
 620
 621         need_in = async->in < 0;
 622         if (need_in) {
 623                 if (pipe(fdin) < 0) {
 624                         if (async->out > 0)
 625                                 close(async->out);
 626                         return error("cannot create pipe: %s", strerror(errno));
 627                 }
 628                 async->in = fdin[1];
 629         }
 630
 631         need_out = async->out < 0;
 632         if (need_out) {
 633                 if (pipe(fdout) < 0) {
 634                         if (need_in)
 635                                 close_pair(fdin);
 636                         else if (async->in)
 637                                 close(async->in);
 638                         return error("cannot create pipe: %s", strerror(errno));
 639                 }
 640                 async->out = fdout[0];
 641         }
 642
 643         if (need_in)
 644                 proc_in = fdin[0];
 645         else if (async->in)
 646                 proc_in = async->in;
 647         else
 648                 proc_in = -1;
 649
 650         if (need_out)
 651                 proc_out = fdout[1];
 652         else if (async->out)
 653                 proc_out = async->out;
 654         else
 655                 proc_out = -1;
 656
 657 #ifdef NO_PTHREADS
 658         /* Flush stdio before fork() to avoid cloning buffers */
 659         fflush(NULL);
 660
 661         async->pid = fork();
 662         if (async->pid < 0) {
 663                 error("fork (async) failed: %s", strerror(errno));
 664                 goto error;
 665         }
 666         if (!async->pid) {
 667                 if (need_in)
 668                         close(fdin[1]);
 669                 if (need_out)
 670                         close(fdout[0]);
 671                 exit(!!async->proc(proc_in, proc_out, async->data));
 672         }
 673
 674         mark_child_for_cleanup(async->pid);
 675
 676         if (need_in)
 677                 close(fdin[0]);
 678         else if (async->in)
 679                 close(async->in);
 680
 681         if (need_out)
 682                 close(fdout[1]);
 683         else if (async->out)
 684                 close(async->out);
 685 #else
 686         if (!main_thread_set) {
 687                 /*
 688                  * We assume that the first time that start_async is called
 689                  * it is from the main thread.
 690                  */
 691                 main_thread_set = 1;
 692                 main_thread = pthread_self();
 693                 pthread_key_create(&async_key, NULL);
 694                 set_die_routine(die_async);
 695         }
 696
 697         if (proc_in >= 0)
 698                 set_cloexec(proc_in);
 699         if (proc_out >= 0)
 700                 set_cloexec(proc_out);
 701         async->proc_in = proc_in;
 702         async->proc_out = proc_out;
 703         {
 704                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 705                 if (err) {
 706                         error("cannot create thread: %s", strerror(err));
 707                         goto error;
 708                 }
 709         }
 710 #endif
 711         return 0;
 712
 713 error:
 714         if (need_in)
 715                 close_pair(fdin);
 716         else if (async->in)
 717                 close(async->in);
 718
 719         if (need_out)
 720                 close_pair(fdout);
 721         else if (async->out)
 722                 close(async->out);
 723         return -1;
 724 }
 725
 726 int finish_async(struct async *async)
 727 {
 728 #ifdef NO_PTHREADS
 729         return wait_or_whine(async->pid, "child process", 0);
 730 #else
 731         void *ret = (void *)(intptr_t)(-1);
 732
 733         if (pthread_join(async->tid, &ret))
 734                 error("pthread_join failed");
 735         return (int)(intptr_t)ret;
 736 #endif
 737 }
 738
 739 int run_hook(const char *index_file, const char *name, ...)
 740 {
 741         struct child_process hook;
 742         struct argv_array argv = ARGV_ARRAY_INIT;
 743         const char *p, *env[2];
 744         char index[PATH_MAX];
 745         va_list args;
 746         int ret;
 747
 748         if (access(git_path("hooks/%s", name), X_OK) < 0)
 749                 return 0;
 750
 751         va_start(args, name);
 752         argv_array_push(&argv, git_path("hooks/%s", name));
 753         while ((p = va_arg(args, const char *)))
 754                 argv_array_push(&argv, p);
 755         va_end(args);
 756
 757         memset(&hook, 0, sizeof(hook));
 758         hook.argv = argv.argv;
 759         hook.no_stdin = 1;
 760         hook.stdout_to_stderr = 1;
 761         if (index_file) {
 762                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 763                 env[0] = index;
 764                 env[1] = NULL;
 765                 hook.env = env;
 766         }
 767
 768         ret = run_command(&hook);
 769         argv_array_clear(&argv);
 770         return ret;
 771 }