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, int silent_exec_failure)
 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                 error("%s died of signal %d", argv0, code);
 246                 /*
 247                  * This return value is chosen so that code & 0xff
 248                  * mimics the exit code that a POSIX shell would report for
 249                  * a program that died from this signal.
 250                  */
 251                 code -= 128;
 252         } else if (WIFEXITED(status)) {
 253                 code = WEXITSTATUS(status);
 254                 /*
 255                  * Convert special exit code when execvp failed.
 256                  */
 257                 if (code == 127) {
 258                         code = -1;
 259                         failed_errno = ENOENT;
 260                 }
 261         } else {
 262                 error("waitpid is confused (%s)", argv0);
 263         }
 264
 265         clear_child_for_cleanup(pid);
 266
 267         errno = failed_errno;
 268         return code;
 269 }
 270
 271 int start_command(struct child_process *cmd)
 272 {
 273         int need_in, need_out, need_err;
 274         int fdin[2], fdout[2], fderr[2];
 275         int failed_errno = failed_errno;
 276
 277         /*
 278          * In case of errors we must keep the promise to close FDs
 279          * that have been passed in via ->in and ->out.
 280          */
 281
 282         need_in = !cmd->no_stdin && cmd->in < 0;
 283         if (need_in) {
 284                 if (pipe(fdin) < 0) {
 285                         failed_errno = errno;
 286                         if (cmd->out > 0)
 287                                 close(cmd->out);
 288                         goto fail_pipe;
 289                 }
 290                 cmd->in = fdin[1];
 291         }
 292
 293         need_out = !cmd->no_stdout
 294                 && !cmd->stdout_to_stderr
 295                 && cmd->out < 0;
 296         if (need_out) {
 297                 if (pipe(fdout) < 0) {
 298                         failed_errno = errno;
 299                         if (need_in)
 300                                 close_pair(fdin);
 301                         else if (cmd->in)
 302                                 close(cmd->in);
 303                         goto fail_pipe;
 304                 }
 305                 cmd->out = fdout[0];
 306         }
 307
 308         need_err = !cmd->no_stderr && cmd->err < 0;
 309         if (need_err) {
 310                 if (pipe(fderr) < 0) {
 311                         failed_errno = errno;
 312                         if (need_in)
 313                                 close_pair(fdin);
 314                         else if (cmd->in)
 315                                 close(cmd->in);
 316                         if (need_out)
 317                                 close_pair(fdout);
 318                         else if (cmd->out)
 319                                 close(cmd->out);
 320 fail_pipe:
 321                         error("cannot create pipe for %s: %s",
 322                                 cmd->argv[0], strerror(failed_errno));
 323                         errno = failed_errno;
 324                         return -1;
 325                 }
 326                 cmd->err = fderr[0];
 327         }
 328
 329         trace_argv_printf(cmd->argv, "trace: run_command:");
 330         fflush(NULL);
 331
 332 #ifndef WIN32
 333 {
 334         int notify_pipe[2];
 335         if (pipe(notify_pipe))
 336                 notify_pipe[0] = notify_pipe[1] = -1;
 337
 338         cmd->pid = fork();
 339         if (!cmd->pid) {
 340                 /*
 341                  * Redirect the channel to write syscall error messages to
 342                  * before redirecting the process's stderr so that all die()
 343                  * in subsequent call paths use the parent's stderr.
 344                  */
 345                 if (cmd->no_stderr || need_err) {
 346                         child_err = dup(2);
 347                         set_cloexec(child_err);
 348                 }
 349                 set_die_routine(die_child);
 350                 set_error_routine(error_child);
 351
 352                 close(notify_pipe[0]);
 353                 set_cloexec(notify_pipe[1]);
 354                 child_notifier = notify_pipe[1];
 355                 atexit(notify_parent);
 356
 357                 if (cmd->no_stdin)
 358                         dup_devnull(0);
 359                 else if (need_in) {
 360                         dup2(fdin[0], 0);
 361                         close_pair(fdin);
 362                 } else if (cmd->in) {
 363                         dup2(cmd->in, 0);
 364                         close(cmd->in);
 365                 }
 366
 367                 if (cmd->no_stderr)
 368                         dup_devnull(2);
 369                 else if (need_err) {
 370                         dup2(fderr[1], 2);
 371                         close_pair(fderr);
 372                 } else if (cmd->err > 1) {
 373                         dup2(cmd->err, 2);
 374                         close(cmd->err);
 375                 }
 376
 377                 if (cmd->no_stdout)
 378                         dup_devnull(1);
 379                 else if (cmd->stdout_to_stderr)
 380                         dup2(2, 1);
 381                 else if (need_out) {
 382                         dup2(fdout[1], 1);
 383                         close_pair(fdout);
 384                 } else if (cmd->out > 1) {
 385                         dup2(cmd->out, 1);
 386                         close(cmd->out);
 387                 }
 388
 389                 if (cmd->dir && chdir(cmd->dir))
 390                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 391                             cmd->dir);
 392                 if (cmd->env) {
 393                         for (; *cmd->env; cmd->env++) {
 394                                 if (strchr(*cmd->env, '='))
 395                                         putenv((char *)*cmd->env);
 396                                 else
 397                                         unsetenv(*cmd->env);
 398                         }
 399                 }
 400                 if (cmd->git_cmd) {
 401                         execv_git_cmd(cmd->argv);
 402                 } else if (cmd->use_shell) {
 403                         execv_shell_cmd(cmd->argv);
 404                 } else {
 405                         sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 406                 }
 407                 if (errno == ENOENT) {
 408                         if (!cmd->silent_exec_failure)
 409                                 error("cannot run %s: %s", cmd->argv[0],
 410                                         strerror(ENOENT));
 411                         exit(127);
 412                 } else {
 413                         die_errno("cannot exec '%s'", cmd->argv[0]);
 414                 }
 415         }
 416         if (cmd->pid < 0)
 417                 error("cannot fork() for %s: %s", cmd->argv[0],
 418                         strerror(failed_errno = errno));
 419         else if (cmd->clean_on_exit)
 420                 mark_child_for_cleanup(cmd->pid);
 421
 422         /*
 423          * Wait for child's execvp. If the execvp succeeds (or if fork()
 424          * failed), EOF is seen immediately by the parent. Otherwise, the
 425          * child process sends a single byte.
 426          * Note that use of this infrastructure is completely advisory,
 427          * therefore, we keep error checks minimal.
 428          */
 429         close(notify_pipe[1]);
 430         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 431                 /*
 432                  * At this point we know that fork() succeeded, but execvp()
 433                  * failed. Errors have been reported to our stderr.
 434                  */
 435                 wait_or_whine(cmd->pid, cmd->argv[0],
 436                               cmd->silent_exec_failure);
 437                 failed_errno = errno;
 438                 cmd->pid = -1;
 439         }
 440         close(notify_pipe[0]);
 441
 442 }
 443 #else
 444 {
 445         int fhin = 0, fhout = 1, fherr = 2;
 446         const char **sargv = cmd->argv;
 447
 448         if (cmd->no_stdin)
 449                 fhin = open("/dev/null", O_RDWR);
 450         else if (need_in)
 451                 fhin = dup(fdin[0]);
 452         else if (cmd->in)
 453                 fhin = dup(cmd->in);
 454
 455         if (cmd->no_stderr)
 456                 fherr = open("/dev/null", O_RDWR);
 457         else if (need_err)
 458                 fherr = dup(fderr[1]);
 459         else if (cmd->err > 2)
 460                 fherr = dup(cmd->err);
 461
 462         if (cmd->no_stdout)
 463                 fhout = open("/dev/null", O_RDWR);
 464         else if (cmd->stdout_to_stderr)
 465                 fhout = dup(fherr);
 466         else if (need_out)
 467                 fhout = dup(fdout[1]);
 468         else if (cmd->out > 1)
 469                 fhout = dup(cmd->out);
 470
 471         if (cmd->git_cmd) {
 472                 cmd->argv = prepare_git_cmd(cmd->argv);
 473         } else if (cmd->use_shell) {
 474                 cmd->argv = prepare_shell_cmd(cmd->argv);
 475         }
 476
 477         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
 478                         cmd->dir, fhin, fhout, fherr);
 479         failed_errno = errno;
 480         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 481                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 482         if (cmd->clean_on_exit && cmd->pid >= 0)
 483                 mark_child_for_cleanup(cmd->pid);
 484
 485         if (cmd->git_cmd)
 486                 free(cmd->argv);
 487
 488         cmd->argv = sargv;
 489         if (fhin != 0)
 490                 close(fhin);
 491         if (fhout != 1)
 492                 close(fhout);
 493         if (fherr != 2)
 494                 close(fherr);
 495 }
 496 #endif
 497
 498         if (cmd->pid < 0) {
 499                 if (need_in)
 500                         close_pair(fdin);
 501                 else if (cmd->in)
 502                         close(cmd->in);
 503                 if (need_out)
 504                         close_pair(fdout);
 505                 else if (cmd->out)
 506                         close(cmd->out);
 507                 if (need_err)
 508                         close_pair(fderr);
 509                 else if (cmd->err)
 510                         close(cmd->err);
 511                 errno = failed_errno;
 512                 return -1;
 513         }
 514
 515         if (need_in)
 516                 close(fdin[0]);
 517         else if (cmd->in)
 518                 close(cmd->in);
 519
 520         if (need_out)
 521                 close(fdout[1]);
 522         else if (cmd->out)
 523                 close(cmd->out);
 524
 525         if (need_err)
 526                 close(fderr[1]);
 527         else if (cmd->err)
 528                 close(cmd->err);
 529
 530         return 0;
 531 }
 532
 533 int finish_command(struct child_process *cmd)
 534 {
 535         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 536 }
 537
 538 int run_command(struct child_process *cmd)
 539 {
 540         int code = start_command(cmd);
 541         if (code)
 542                 return code;
 543         return finish_command(cmd);
 544 }
 545
 546 static void prepare_run_command_v_opt(struct child_process *cmd,
 547                                       const char **argv,
 548                                       int opt)
 549 {
 550         memset(cmd, 0, sizeof(*cmd));
 551         cmd->argv = argv;
 552         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 553         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 554         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 555         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 556         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 557         cmd->clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 558 }
 559
 560 int run_command_v_opt(const char **argv, int opt)
 561 {
 562         struct child_process cmd;
 563         prepare_run_command_v_opt(&cmd, argv, opt);
 564         return run_command(&cmd);
 565 }
 566
 567 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 568 {
 569         struct child_process cmd;
 570         prepare_run_command_v_opt(&cmd, argv, opt);
 571         cmd.dir = dir;
 572         cmd.env = env;
 573         return run_command(&cmd);
 574 }
 575
 576 #ifndef NO_PTHREADS
 577 static pthread_t main_thread;
 578 static int main_thread_set;
 579 static pthread_key_t async_key;
 580
 581 static void *run_thread(void *data)
 582 {
 583         struct async *async = data;
 584         intptr_t ret;
 585
 586         pthread_setspecific(async_key, async);
 587         ret = async->proc(async->proc_in, async->proc_out, async->data);
 588         return (void *)ret;
 589 }
 590
 591 static NORETURN void die_async(const char *err, va_list params)
 592 {
 593         vreportf("fatal: ", err, params);
 594
 595         if (!pthread_equal(main_thread, pthread_self())) {
 596                 struct async *async = pthread_getspecific(async_key);
 597                 if (async->proc_in >= 0)
 598                         close(async->proc_in);
 599                 if (async->proc_out >= 0)
 600                         close(async->proc_out);
 601                 pthread_exit((void *)128);
 602         }
 603
 604         exit(128);
 605 }
 606 #endif
 607
 608 int start_async(struct async *async)
 609 {
 610         int need_in, need_out;
 611         int fdin[2], fdout[2];
 612         int proc_in, proc_out;
 613
 614         need_in = async->in < 0;
 615         if (need_in) {
 616                 if (pipe(fdin) < 0) {
 617                         if (async->out > 0)
 618                                 close(async->out);
 619                         return error("cannot create pipe: %s", strerror(errno));
 620                 }
 621                 async->in = fdin[1];
 622         }
 623
 624         need_out = async->out < 0;
 625         if (need_out) {
 626                 if (pipe(fdout) < 0) {
 627                         if (need_in)
 628                                 close_pair(fdin);
 629                         else if (async->in)
 630                                 close(async->in);
 631                         return error("cannot create pipe: %s", strerror(errno));
 632                 }
 633                 async->out = fdout[0];
 634         }
 635
 636         if (need_in)
 637                 proc_in = fdin[0];
 638         else if (async->in)
 639                 proc_in = async->in;
 640         else
 641                 proc_in = -1;
 642
 643         if (need_out)
 644                 proc_out = fdout[1];
 645         else if (async->out)
 646                 proc_out = async->out;
 647         else
 648                 proc_out = -1;
 649
 650 #ifdef NO_PTHREADS
 651         /* Flush stdio before fork() to avoid cloning buffers */
 652         fflush(NULL);
 653
 654         async->pid = fork();
 655         if (async->pid < 0) {
 656                 error("fork (async) failed: %s", strerror(errno));
 657                 goto error;
 658         }
 659         if (!async->pid) {
 660                 if (need_in)
 661                         close(fdin[1]);
 662                 if (need_out)
 663                         close(fdout[0]);
 664                 exit(!!async->proc(proc_in, proc_out, async->data));
 665         }
 666
 667         mark_child_for_cleanup(async->pid);
 668
 669         if (need_in)
 670                 close(fdin[0]);
 671         else if (async->in)
 672                 close(async->in);
 673
 674         if (need_out)
 675                 close(fdout[1]);
 676         else if (async->out)
 677                 close(async->out);
 678 #else
 679         if (!main_thread_set) {
 680                 /*
 681                  * We assume that the first time that start_async is called
 682                  * it is from the main thread.
 683                  */
 684                 main_thread_set = 1;
 685                 main_thread = pthread_self();
 686                 pthread_key_create(&async_key, NULL);
 687                 set_die_routine(die_async);
 688         }
 689
 690         if (proc_in >= 0)
 691                 set_cloexec(proc_in);
 692         if (proc_out >= 0)
 693                 set_cloexec(proc_out);
 694         async->proc_in = proc_in;
 695         async->proc_out = proc_out;
 696         {
 697                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 698                 if (err) {
 699                         error("cannot create thread: %s", strerror(err));
 700                         goto error;
 701                 }
 702         }
 703 #endif
 704         return 0;
 705
 706 error:
 707         if (need_in)
 708                 close_pair(fdin);
 709         else if (async->in)
 710                 close(async->in);
 711
 712         if (need_out)
 713                 close_pair(fdout);
 714         else if (async->out)
 715                 close(async->out);
 716         return -1;
 717 }
 718
 719 int finish_async(struct async *async)
 720 {
 721 #ifdef NO_PTHREADS
 722         return wait_or_whine(async->pid, "child process", 0);
 723 #else
 724         void *ret = (void *)(intptr_t)(-1);
 725
 726         if (pthread_join(async->tid, &ret))
 727                 error("pthread_join failed");
 728         return (int)(intptr_t)ret;
 729 #endif
 730 }
 731
 732 int run_hook(const char *index_file, const char *name, ...)
 733 {
 734         struct child_process hook;
 735         struct argv_array argv = ARGV_ARRAY_INIT;
 736         const char *p, *env[2];
 737         char index[PATH_MAX];
 738         va_list args;
 739         int ret;
 740
 741         if (access(git_path("hooks/%s", name), X_OK) < 0)
 742                 return 0;
 743
 744         va_start(args, name);
 745         argv_array_push(&argv, git_path("hooks/%s", name));
 746         while ((p = va_arg(args, const char *)))
 747                 argv_array_push(&argv, p);
 748         va_end(args);
 749
 750         memset(&hook, 0, sizeof(hook));
 751         hook.argv = argv.argv;
 752         hook.no_stdin = 1;
 753         hook.stdout_to_stderr = 1;
 754         if (index_file) {
 755                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 756                 env[0] = index;
 757                 env[1] = NULL;
 758                 hook.env = env;
 759         }
 760
 761         ret = run_command(&hook);
 762         argv_array_clear(&argv);
 763         return ret;
 764 }