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                 nargv[nargc++] = SHELL_PATH;
 160                 nargv[nargc++] = "-c";
 161
 162                 if (argc < 2)
 163                         nargv[nargc++] = argv[0];
 164                 else {
 165                         struct strbuf arg0 = STRBUF_INIT;
 166                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 167                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
 168                 }
 169         }
 170
 171         for (argc = 0; argv[argc]; argc++)
 172                 nargv[nargc++] = argv[argc];
 173         nargv[nargc] = NULL;
 174
 175         return nargv;
 176 }
 177
 178 #ifndef WIN32
 179 static int execv_shell_cmd(const char **argv)
 180 {
 181         const char **nargv = prepare_shell_cmd(argv);
 182         trace_argv_printf(nargv, "trace: exec:");
 183         sane_execvp(nargv[0], (char **)nargv);
 184         free(nargv);
 185         return -1;
 186 }
 187 #endif
 188
 189 #ifndef WIN32
 190 static int child_err = 2;
 191 static int child_notifier = -1;
 192
 193 static void notify_parent(void)
 194 {
 195         /*
 196          * execvp failed.  If possible, we'd like to let start_command
 197          * know, so failures like ENOENT can be handled right away; but
 198          * otherwise, finish_command will still report the error.
 199          */
 200         xwrite(child_notifier, "", 1);
 201 }
 202
 203 static NORETURN void die_child(const char *err, va_list params)
 204 {
 205         vwritef(child_err, "fatal: ", err, params);
 206         exit(128);
 207 }
 208
 209 static void error_child(const char *err, va_list params)
 210 {
 211         vwritef(child_err, "error: ", err, params);
 212 }
 213 #endif
 214
 215 static inline void set_cloexec(int fd)
 216 {
 217         int flags = fcntl(fd, F_GETFD);
 218         if (flags >= 0)
 219                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 220 }
 221
 222 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 223 {
 224         int status, code = -1;
 225         pid_t waiting;
 226         int failed_errno = 0;
 227
 228         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 229                 ;       /* nothing */
 230
 231         if (waiting < 0) {
 232                 failed_errno = errno;
 233                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 234         } else if (waiting != pid) {
 235                 error("waitpid is confused (%s)", argv0);
 236         } else if (WIFSIGNALED(status)) {
 237                 code = WTERMSIG(status);
 238                 error("%s died of signal %d", argv0, code);
 239                 /*
 240                  * This return value is chosen so that code & 0xff
 241                  * mimics the exit code that a POSIX shell would report for
 242                  * a program that died from this signal.
 243                  */
 244                 code -= 128;
 245         } else if (WIFEXITED(status)) {
 246                 code = WEXITSTATUS(status);
 247                 /*
 248                  * Convert special exit code when execvp failed.
 249                  */
 250                 if (code == 127) {
 251                         code = -1;
 252                         failed_errno = ENOENT;
 253                 }
 254         } else {
 255                 error("waitpid is confused (%s)", argv0);
 256         }
 257
 258         clear_child_for_cleanup(pid);
 259
 260         errno = failed_errno;
 261         return code;
 262 }
 263
 264 int start_command(struct child_process *cmd)
 265 {
 266         int need_in, need_out, need_err;
 267         int fdin[2], fdout[2], fderr[2];
 268         int failed_errno = failed_errno;
 269
 270         /*
 271          * In case of errors we must keep the promise to close FDs
 272          * that have been passed in via ->in and ->out.
 273          */
 274
 275         need_in = !cmd->no_stdin && cmd->in < 0;
 276         if (need_in) {
 277                 if (pipe(fdin) < 0) {
 278                         failed_errno = errno;
 279                         if (cmd->out > 0)
 280                                 close(cmd->out);
 281                         goto fail_pipe;
 282                 }
 283                 cmd->in = fdin[1];
 284         }
 285
 286         need_out = !cmd->no_stdout
 287                 && !cmd->stdout_to_stderr
 288                 && cmd->out < 0;
 289         if (need_out) {
 290                 if (pipe(fdout) < 0) {
 291                         failed_errno = errno;
 292                         if (need_in)
 293                                 close_pair(fdin);
 294                         else if (cmd->in)
 295                                 close(cmd->in);
 296                         goto fail_pipe;
 297                 }
 298                 cmd->out = fdout[0];
 299         }
 300
 301         need_err = !cmd->no_stderr && cmd->err < 0;
 302         if (need_err) {
 303                 if (pipe(fderr) < 0) {
 304                         failed_errno = errno;
 305                         if (need_in)
 306                                 close_pair(fdin);
 307                         else if (cmd->in)
 308                                 close(cmd->in);
 309                         if (need_out)
 310                                 close_pair(fdout);
 311                         else if (cmd->out)
 312                                 close(cmd->out);
 313 fail_pipe:
 314                         error("cannot create pipe for %s: %s",
 315                                 cmd->argv[0], strerror(failed_errno));
 316                         errno = failed_errno;
 317                         return -1;
 318                 }
 319                 cmd->err = fderr[0];
 320         }
 321
 322         trace_argv_printf(cmd->argv, "trace: run_command:");
 323         fflush(NULL);
 324
 325 #ifndef WIN32
 326 {
 327         int notify_pipe[2];
 328         if (pipe(notify_pipe))
 329                 notify_pipe[0] = notify_pipe[1] = -1;
 330
 331         cmd->pid = fork();
 332         if (!cmd->pid) {
 333                 /*
 334                  * Redirect the channel to write syscall error messages to
 335                  * before redirecting the process's stderr so that all die()
 336                  * in subsequent call paths use the parent's stderr.
 337                  */
 338                 if (cmd->no_stderr || need_err) {
 339                         child_err = dup(2);
 340                         set_cloexec(child_err);
 341                 }
 342                 set_die_routine(die_child);
 343                 set_error_routine(error_child);
 344
 345                 close(notify_pipe[0]);
 346                 set_cloexec(notify_pipe[1]);
 347                 child_notifier = notify_pipe[1];
 348                 atexit(notify_parent);
 349
 350                 if (cmd->no_stdin)
 351                         dup_devnull(0);
 352                 else if (need_in) {
 353                         dup2(fdin[0], 0);
 354                         close_pair(fdin);
 355                 } else if (cmd->in) {
 356                         dup2(cmd->in, 0);
 357                         close(cmd->in);
 358                 }
 359
 360                 if (cmd->no_stderr)
 361                         dup_devnull(2);
 362                 else if (need_err) {
 363                         dup2(fderr[1], 2);
 364                         close_pair(fderr);
 365                 } else if (cmd->err > 1) {
 366                         dup2(cmd->err, 2);
 367                         close(cmd->err);
 368                 }
 369
 370                 if (cmd->no_stdout)
 371                         dup_devnull(1);
 372                 else if (cmd->stdout_to_stderr)
 373                         dup2(2, 1);
 374                 else if (need_out) {
 375                         dup2(fdout[1], 1);
 376                         close_pair(fdout);
 377                 } else if (cmd->out > 1) {
 378                         dup2(cmd->out, 1);
 379                         close(cmd->out);
 380                 }
 381
 382                 if (cmd->dir && chdir(cmd->dir))
 383                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 384                             cmd->dir);
 385                 if (cmd->env) {
 386                         for (; *cmd->env; cmd->env++) {
 387                                 if (strchr(*cmd->env, '='))
 388                                         putenv((char *)*cmd->env);
 389                                 else
 390                                         unsetenv(*cmd->env);
 391                         }
 392                 }
 393                 if (cmd->preexec_cb) {
 394                         /*
 395                          * We cannot predict what the pre-exec callback does.
 396                          * Forgo parent notification.
 397                          */
 398                         close(child_notifier);
 399                         child_notifier = -1;
 400
 401                         cmd->preexec_cb();
 402                 }
 403                 if (cmd->git_cmd) {
 404                         execv_git_cmd(cmd->argv);
 405                 } else if (cmd->use_shell) {
 406                         execv_shell_cmd(cmd->argv);
 407                 } else {
 408                         sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
 409                 }
 410                 if (errno == ENOENT) {
 411                         if (!cmd->silent_exec_failure)
 412                                 error("cannot run %s: %s", cmd->argv[0],
 413                                         strerror(ENOENT));
 414                         exit(127);
 415                 } else {
 416                         die_errno("cannot exec '%s'", cmd->argv[0]);
 417                 }
 418         }
 419         if (cmd->pid < 0)
 420                 error("cannot fork() for %s: %s", cmd->argv[0],
 421                         strerror(failed_errno = errno));
 422         else if (cmd->clean_on_exit)
 423                 mark_child_for_cleanup(cmd->pid);
 424
 425         /*
 426          * Wait for child's execvp. If the execvp succeeds (or if fork()
 427          * failed), EOF is seen immediately by the parent. Otherwise, the
 428          * child process sends a single byte.
 429          * Note that use of this infrastructure is completely advisory,
 430          * therefore, we keep error checks minimal.
 431          */
 432         close(notify_pipe[1]);
 433         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 434                 /*
 435                  * At this point we know that fork() succeeded, but execvp()
 436                  * failed. Errors have been reported to our stderr.
 437                  */
 438                 wait_or_whine(cmd->pid, cmd->argv[0],
 439                               cmd->silent_exec_failure);
 440                 failed_errno = errno;
 441                 cmd->pid = -1;
 442         }
 443         close(notify_pipe[0]);
 444
 445 }
 446 #else
 447 {
 448         int fhin = 0, fhout = 1, fherr = 2;
 449         const char **sargv = cmd->argv;
 450         char **env = environ;
 451
 452         if (cmd->no_stdin)
 453                 fhin = open("/dev/null", O_RDWR);
 454         else if (need_in)
 455                 fhin = dup(fdin[0]);
 456         else if (cmd->in)
 457                 fhin = dup(cmd->in);
 458
 459         if (cmd->no_stderr)
 460                 fherr = open("/dev/null", O_RDWR);
 461         else if (need_err)
 462                 fherr = dup(fderr[1]);
 463         else if (cmd->err > 2)
 464                 fherr = dup(cmd->err);
 465
 466         if (cmd->no_stdout)
 467                 fhout = open("/dev/null", O_RDWR);
 468         else if (cmd->stdout_to_stderr)
 469                 fhout = dup(fherr);
 470         else if (need_out)
 471                 fhout = dup(fdout[1]);
 472         else if (cmd->out > 1)
 473                 fhout = dup(cmd->out);
 474
 475         if (cmd->env)
 476                 env = make_augmented_environ(cmd->env);
 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, env, cmd->dir,
 485                                   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->env)
 493                 free_environ(env);
 494         if (cmd->git_cmd)
 495                 free(cmd->argv);
 496
 497         cmd->argv = sargv;
 498         if (fhin != 0)
 499                 close(fhin);
 500         if (fhout != 1)
 501                 close(fhout);
 502         if (fherr != 2)
 503                 close(fherr);
 504 }
 505 #endif
 506
 507         if (cmd->pid < 0) {
 508                 if (need_in)
 509                         close_pair(fdin);
 510                 else if (cmd->in)
 511                         close(cmd->in);
 512                 if (need_out)
 513                         close_pair(fdout);
 514                 else if (cmd->out)
 515                         close(cmd->out);
 516                 if (need_err)
 517                         close_pair(fderr);
 518                 else if (cmd->err)
 519                         close(cmd->err);
 520                 errno = failed_errno;
 521                 return -1;
 522         }
 523
 524         if (need_in)
 525                 close(fdin[0]);
 526         else if (cmd->in)
 527                 close(cmd->in);
 528
 529         if (need_out)
 530                 close(fdout[1]);
 531         else if (cmd->out)
 532                 close(cmd->out);
 533
 534         if (need_err)
 535                 close(fderr[1]);
 536         else if (cmd->err)
 537                 close(cmd->err);
 538
 539         return 0;
 540 }
 541
 542 int finish_command(struct child_process *cmd)
 543 {
 544         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 545 }
 546
 547 int run_command(struct child_process *cmd)
 548 {
 549         int code = start_command(cmd);
 550         if (code)
 551                 return code;
 552         return finish_command(cmd);
 553 }
 554
 555 static void prepare_run_command_v_opt(struct child_process *cmd,
 556                                       const char **argv,
 557                                       int opt)
 558 {
 559         memset(cmd, 0, sizeof(*cmd));
 560         cmd->argv = argv;
 561         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 562         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 563         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 564         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 565         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 566         cmd->clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 567 }
 568
 569 int run_command_v_opt(const char **argv, int opt)
 570 {
 571         struct child_process cmd;
 572         prepare_run_command_v_opt(&cmd, argv, opt);
 573         return run_command(&cmd);
 574 }
 575
 576 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 577 {
 578         struct child_process cmd;
 579         prepare_run_command_v_opt(&cmd, argv, opt);
 580         cmd.dir = dir;
 581         cmd.env = env;
 582         return run_command(&cmd);
 583 }
 584
 585 #ifndef NO_PTHREADS
 586 static pthread_t main_thread;
 587 static int main_thread_set;
 588 static pthread_key_t async_key;
 589
 590 static void *run_thread(void *data)
 591 {
 592         struct async *async = data;
 593         intptr_t ret;
 594
 595         pthread_setspecific(async_key, async);
 596         ret = async->proc(async->proc_in, async->proc_out, async->data);
 597         return (void *)ret;
 598 }
 599
 600 static NORETURN void die_async(const char *err, va_list params)
 601 {
 602         vreportf("fatal: ", err, params);
 603
 604         if (!pthread_equal(main_thread, pthread_self())) {
 605                 struct async *async = pthread_getspecific(async_key);
 606                 if (async->proc_in >= 0)
 607                         close(async->proc_in);
 608                 if (async->proc_out >= 0)
 609                         close(async->proc_out);
 610                 pthread_exit((void *)128);
 611         }
 612
 613         exit(128);
 614 }
 615 #endif
 616
 617 int start_async(struct async *async)
 618 {
 619         int need_in, need_out;
 620         int fdin[2], fdout[2];
 621         int proc_in, proc_out;
 622
 623         need_in = async->in < 0;
 624         if (need_in) {
 625                 if (pipe(fdin) < 0) {
 626                         if (async->out > 0)
 627                                 close(async->out);
 628                         return error("cannot create pipe: %s", strerror(errno));
 629                 }
 630                 async->in = fdin[1];
 631         }
 632
 633         need_out = async->out < 0;
 634         if (need_out) {
 635                 if (pipe(fdout) < 0) {
 636                         if (need_in)
 637                                 close_pair(fdin);
 638                         else if (async->in)
 639                                 close(async->in);
 640                         return error("cannot create pipe: %s", strerror(errno));
 641                 }
 642                 async->out = fdout[0];
 643         }
 644
 645         if (need_in)
 646                 proc_in = fdin[0];
 647         else if (async->in)
 648                 proc_in = async->in;
 649         else
 650                 proc_in = -1;
 651
 652         if (need_out)
 653                 proc_out = fdout[1];
 654         else if (async->out)
 655                 proc_out = async->out;
 656         else
 657                 proc_out = -1;
 658
 659 #ifdef NO_PTHREADS
 660         /* Flush stdio before fork() to avoid cloning buffers */
 661         fflush(NULL);
 662
 663         async->pid = fork();
 664         if (async->pid < 0) {
 665                 error("fork (async) failed: %s", strerror(errno));
 666                 goto error;
 667         }
 668         if (!async->pid) {
 669                 if (need_in)
 670                         close(fdin[1]);
 671                 if (need_out)
 672                         close(fdout[0]);
 673                 exit(!!async->proc(proc_in, proc_out, async->data));
 674         }
 675
 676         mark_child_for_cleanup(async->pid);
 677
 678         if (need_in)
 679                 close(fdin[0]);
 680         else if (async->in)
 681                 close(async->in);
 682
 683         if (need_out)
 684                 close(fdout[1]);
 685         else if (async->out)
 686                 close(async->out);
 687 #else
 688         if (!main_thread_set) {
 689                 /*
 690                  * We assume that the first time that start_async is called
 691                  * it is from the main thread.
 692                  */
 693                 main_thread_set = 1;
 694                 main_thread = pthread_self();
 695                 pthread_key_create(&async_key, NULL);
 696                 set_die_routine(die_async);
 697         }
 698
 699         if (proc_in >= 0)
 700                 set_cloexec(proc_in);
 701         if (proc_out >= 0)
 702                 set_cloexec(proc_out);
 703         async->proc_in = proc_in;
 704         async->proc_out = proc_out;
 705         {
 706                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 707                 if (err) {
 708                         error("cannot create thread: %s", strerror(err));
 709                         goto error;
 710                 }
 711         }
 712 #endif
 713         return 0;
 714
 715 error:
 716         if (need_in)
 717                 close_pair(fdin);
 718         else if (async->in)
 719                 close(async->in);
 720
 721         if (need_out)
 722                 close_pair(fdout);
 723         else if (async->out)
 724                 close(async->out);
 725         return -1;
 726 }
 727
 728 int finish_async(struct async *async)
 729 {
 730 #ifdef NO_PTHREADS
 731         return wait_or_whine(async->pid, "child process", 0);
 732 #else
 733         void *ret = (void *)(intptr_t)(-1);
 734
 735         if (pthread_join(async->tid, &ret))
 736                 error("pthread_join failed");
 737         return (int)(intptr_t)ret;
 738 #endif
 739 }
 740
 741 int run_hook(const char *index_file, const char *name, ...)
 742 {
 743         struct child_process hook;
 744         struct argv_array argv = ARGV_ARRAY_INIT;
 745         const char *p, *env[2];
 746         char index[PATH_MAX];
 747         va_list args;
 748         int ret;
 749
 750         if (access(git_path("hooks/%s", name), X_OK) < 0)
 751                 return 0;
 752
 753         va_start(args, name);
 754         argv_array_push(&argv, git_path("hooks/%s", name));
 755         while ((p = va_arg(args, const char *)))
 756                 argv_array_push(&argv, p);
 757         va_end(args);
 758
 759         memset(&hook, 0, sizeof(hook));
 760         hook.argv = argv.argv;
 761         hook.no_stdin = 1;
 762         hook.stdout_to_stderr = 1;
 763         if (index_file) {
 764                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 765                 env[0] = index;
 766                 env[1] = NULL;
 767                 hook.env = env;
 768         }
 769
 770         ret = run_command(&hook);
 771         argv_array_clear(&argv);
 772         return ret;
 773 }