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