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 struct child_to_clean {
   8         pid_t pid;
   9         struct child_to_clean *next;
  10 };
  11 static struct child_to_clean *children_to_clean;
  12 static int installed_child_cleanup_handler;
  13
  14 static void cleanup_children(int sig)
  15 {
  16         while (children_to_clean) {
  17                 struct child_to_clean *p = children_to_clean;
  18                 children_to_clean = p->next;
  19                 kill(p->pid, sig);
  20                 free(p);
  21         }
  22 }
  23
  24 static void cleanup_children_on_signal(int sig)
  25 {
  26         cleanup_children(sig);
  27         sigchain_pop(sig);
  28         raise(sig);
  29 }
  30
  31 static void cleanup_children_on_exit(void)
  32 {
  33         cleanup_children(SIGTERM);
  34 }
  35
  36 static void mark_child_for_cleanup(pid_t pid)
  37 {
  38         struct child_to_clean *p = xmalloc(sizeof(*p));
  39         p->pid = pid;
  40         p->next = children_to_clean;
  41         children_to_clean = p;
  42
  43         if (!installed_child_cleanup_handler) {
  44                 atexit(cleanup_children_on_exit);
  45                 sigchain_push_common(cleanup_children_on_signal);
  46                 installed_child_cleanup_handler = 1;
  47         }
  48 }
  49
  50 static void clear_child_for_cleanup(pid_t pid)
  51 {
  52         struct child_to_clean **pp;
  53
  54         for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
  55                 struct child_to_clean *clean_me = *pp;
  56
  57                 if (clean_me->pid == pid) {
  58                         *pp = clean_me->next;
  59                         free(clean_me);
  60                         return;
  61                 }
  62         }
  63 }
  64
  65 static inline void close_pair(int fd[2])
  66 {
  67         close(fd[0]);
  68         close(fd[1]);
  69 }
  70
  71 #ifndef WIN32
  72 static inline void dup_devnull(int to)
  73 {
  74         int fd = open("/dev/null", O_RDWR);
  75         dup2(fd, to);
  76         close(fd);
  77 }
  78 #endif
  79
  80 static const char **prepare_shell_cmd(const char **argv)
  81 {
  82         int argc, nargc = 0;
  83         const char **nargv;
  84
  85         for (argc = 0; argv[argc]; argc++)
  86                 ; /* just counting */
  87         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
  88         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
  89
  90         if (argc < 1)
  91                 die("BUG: shell command is empty");
  92
  93         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
  94                 nargv[nargc++] = "sh";
  95                 nargv[nargc++] = "-c";
  96
  97                 if (argc < 2)
  98                         nargv[nargc++] = argv[0];
  99                 else {
 100                         struct strbuf arg0 = STRBUF_INIT;
 101                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
 102                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
 103                 }
 104         }
 105
 106         for (argc = 0; argv[argc]; argc++)
 107                 nargv[nargc++] = argv[argc];
 108         nargv[nargc] = NULL;
 109
 110         return nargv;
 111 }
 112
 113 #ifndef WIN32
 114 static int execv_shell_cmd(const char **argv)
 115 {
 116         const char **nargv = prepare_shell_cmd(argv);
 117         trace_argv_printf(nargv, "trace: exec:");
 118         execvp(nargv[0], (char **)nargv);
 119         free(nargv);
 120         return -1;
 121 }
 122 #endif
 123
 124 #ifndef WIN32
 125 static int child_err = 2;
 126 static int child_notifier = -1;
 127
 128 static void notify_parent(void)
 129 {
 130         /*
 131          * execvp failed.  If possible, we'd like to let start_command
 132          * know, so failures like ENOENT can be handled right away; but
 133          * otherwise, finish_command will still report the error.
 134          */
 135         xwrite(child_notifier, "", 1);
 136 }
 137
 138 static NORETURN void die_child(const char *err, va_list params)
 139 {
 140         vwritef(child_err, "fatal: ", err, params);
 141         exit(128);
 142 }
 143
 144 static void error_child(const char *err, va_list params)
 145 {
 146         vwritef(child_err, "error: ", err, params);
 147 }
 148 #endif
 149
 150 static inline void set_cloexec(int fd)
 151 {
 152         int flags = fcntl(fd, F_GETFD);
 153         if (flags >= 0)
 154                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 155 }
 156
 157 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 158 {
 159         int status, code = -1;
 160         pid_t waiting;
 161         int failed_errno = 0;
 162
 163         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 164                 ;       /* nothing */
 165
 166         if (waiting < 0) {
 167                 failed_errno = errno;
 168                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 169         } else if (waiting != pid) {
 170                 error("waitpid is confused (%s)", argv0);
 171         } else if (WIFSIGNALED(status)) {
 172                 code = WTERMSIG(status);
 173                 error("%s died of signal %d", argv0, code);
 174                 /*
 175                  * This return value is chosen so that code & 0xff
 176                  * mimics the exit code that a POSIX shell would report for
 177                  * a program that died from this signal.
 178                  */
 179                 code -= 128;
 180         } else if (WIFEXITED(status)) {
 181                 code = WEXITSTATUS(status);
 182                 /*
 183                  * Convert special exit code when execvp failed.
 184                  */
 185                 if (code == 127) {
 186                         code = -1;
 187                         failed_errno = ENOENT;
 188                 }
 189         } else {
 190                 error("waitpid is confused (%s)", argv0);
 191         }
 192
 193         clear_child_for_cleanup(pid);
 194
 195         errno = failed_errno;
 196         return code;
 197 }
 198
 199 int start_command(struct child_process *cmd)
 200 {
 201         int need_in, need_out, need_err;
 202         int fdin[2], fdout[2], fderr[2];
 203         int failed_errno = failed_errno;
 204
 205         /*
 206          * In case of errors we must keep the promise to close FDs
 207          * that have been passed in via ->in and ->out.
 208          */
 209
 210         need_in = !cmd->no_stdin && cmd->in < 0;
 211         if (need_in) {
 212                 if (pipe(fdin) < 0) {
 213                         failed_errno = errno;
 214                         if (cmd->out > 0)
 215                                 close(cmd->out);
 216                         goto fail_pipe;
 217                 }
 218                 cmd->in = fdin[1];
 219         }
 220
 221         need_out = !cmd->no_stdout
 222                 && !cmd->stdout_to_stderr
 223                 && cmd->out < 0;
 224         if (need_out) {
 225                 if (pipe(fdout) < 0) {
 226                         failed_errno = errno;
 227                         if (need_in)
 228                                 close_pair(fdin);
 229                         else if (cmd->in)
 230                                 close(cmd->in);
 231                         goto fail_pipe;
 232                 }
 233                 cmd->out = fdout[0];
 234         }
 235
 236         need_err = !cmd->no_stderr && cmd->err < 0;
 237         if (need_err) {
 238                 if (pipe(fderr) < 0) {
 239                         failed_errno = errno;
 240                         if (need_in)
 241                                 close_pair(fdin);
 242                         else if (cmd->in)
 243                                 close(cmd->in);
 244                         if (need_out)
 245                                 close_pair(fdout);
 246                         else if (cmd->out)
 247                                 close(cmd->out);
 248 fail_pipe:
 249                         error("cannot create pipe for %s: %s",
 250                                 cmd->argv[0], strerror(failed_errno));
 251                         errno = failed_errno;
 252                         return -1;
 253                 }
 254                 cmd->err = fderr[0];
 255         }
 256
 257         trace_argv_printf(cmd->argv, "trace: run_command:");
 258         fflush(NULL);
 259
 260 #ifndef WIN32
 261 {
 262         int notify_pipe[2];
 263         if (pipe(notify_pipe))
 264                 notify_pipe[0] = notify_pipe[1] = -1;
 265
 266         cmd->pid = fork();
 267         if (!cmd->pid) {
 268                 /*
 269                  * Redirect the channel to write syscall error messages to
 270                  * before redirecting the process's stderr so that all die()
 271                  * in subsequent call paths use the parent's stderr.
 272                  */
 273                 if (cmd->no_stderr || need_err) {
 274                         child_err = dup(2);
 275                         set_cloexec(child_err);
 276                 }
 277                 set_die_routine(die_child);
 278                 set_error_routine(error_child);
 279
 280                 close(notify_pipe[0]);
 281                 set_cloexec(notify_pipe[1]);
 282                 child_notifier = notify_pipe[1];
 283                 atexit(notify_parent);
 284
 285                 if (cmd->no_stdin)
 286                         dup_devnull(0);
 287                 else if (need_in) {
 288                         dup2(fdin[0], 0);
 289                         close_pair(fdin);
 290                 } else if (cmd->in) {
 291                         dup2(cmd->in, 0);
 292                         close(cmd->in);
 293                 }
 294
 295                 if (cmd->no_stderr)
 296                         dup_devnull(2);
 297                 else if (need_err) {
 298                         dup2(fderr[1], 2);
 299                         close_pair(fderr);
 300                 } else if (cmd->err > 1) {
 301                         dup2(cmd->err, 2);
 302                         close(cmd->err);
 303                 }
 304
 305                 if (cmd->no_stdout)
 306                         dup_devnull(1);
 307                 else if (cmd->stdout_to_stderr)
 308                         dup2(2, 1);
 309                 else if (need_out) {
 310                         dup2(fdout[1], 1);
 311                         close_pair(fdout);
 312                 } else if (cmd->out > 1) {
 313                         dup2(cmd->out, 1);
 314                         close(cmd->out);
 315                 }
 316
 317                 if (cmd->dir && chdir(cmd->dir))
 318                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 319                             cmd->dir);
 320                 if (cmd->env) {
 321                         for (; *cmd->env; cmd->env++) {
 322                                 if (strchr(*cmd->env, '='))
 323                                         putenv((char *)*cmd->env);
 324                                 else
 325                                         unsetenv(*cmd->env);
 326                         }
 327                 }
 328                 if (cmd->preexec_cb) {
 329                         /*
 330                          * We cannot predict what the pre-exec callback does.
 331                          * Forgo parent notification.
 332                          */
 333                         close(child_notifier);
 334                         child_notifier = -1;
 335
 336                         cmd->preexec_cb();
 337                 }
 338                 if (cmd->git_cmd) {
 339                         execv_git_cmd(cmd->argv);
 340                 } else if (cmd->use_shell) {
 341                         execv_shell_cmd(cmd->argv);
 342                 } else {
 343                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 344                 }
 345                 if (errno == ENOENT) {
 346                         if (!cmd->silent_exec_failure)
 347                                 error("cannot run %s: %s", cmd->argv[0],
 348                                         strerror(ENOENT));
 349                         exit(127);
 350                 } else {
 351                         die_errno("cannot exec '%s'", cmd->argv[0]);
 352                 }
 353         }
 354         if (cmd->pid < 0)
 355                 error("cannot fork() for %s: %s", cmd->argv[0],
 356                         strerror(failed_errno = errno));
 357         else if (cmd->clean_on_exit)
 358                 mark_child_for_cleanup(cmd->pid);
 359
 360         /*
 361          * Wait for child's execvp. If the execvp succeeds (or if fork()
 362          * failed), EOF is seen immediately by the parent. Otherwise, the
 363          * child process sends a single byte.
 364          * Note that use of this infrastructure is completely advisory,
 365          * therefore, we keep error checks minimal.
 366          */
 367         close(notify_pipe[1]);
 368         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 369                 /*
 370                  * At this point we know that fork() succeeded, but execvp()
 371                  * failed. Errors have been reported to our stderr.
 372                  */
 373                 wait_or_whine(cmd->pid, cmd->argv[0],
 374                               cmd->silent_exec_failure);
 375                 failed_errno = errno;
 376                 cmd->pid = -1;
 377         }
 378         close(notify_pipe[0]);
 379
 380 }
 381 #else
 382 {
 383         int fhin = 0, fhout = 1, fherr = 2;
 384         const char **sargv = cmd->argv;
 385         char **env = environ;
 386
 387         if (cmd->no_stdin)
 388                 fhin = open("/dev/null", O_RDWR);
 389         else if (need_in)
 390                 fhin = dup(fdin[0]);
 391         else if (cmd->in)
 392                 fhin = dup(cmd->in);
 393
 394         if (cmd->no_stderr)
 395                 fherr = open("/dev/null", O_RDWR);
 396         else if (need_err)
 397                 fherr = dup(fderr[1]);
 398         else if (cmd->err > 2)
 399                 fherr = dup(cmd->err);
 400
 401         if (cmd->no_stdout)
 402                 fhout = open("/dev/null", O_RDWR);
 403         else if (cmd->stdout_to_stderr)
 404                 fhout = dup(fherr);
 405         else if (need_out)
 406                 fhout = dup(fdout[1]);
 407         else if (cmd->out > 1)
 408                 fhout = dup(cmd->out);
 409
 410         if (cmd->env)
 411                 env = make_augmented_environ(cmd->env);
 412
 413         if (cmd->git_cmd) {
 414                 cmd->argv = prepare_git_cmd(cmd->argv);
 415         } else if (cmd->use_shell) {
 416                 cmd->argv = prepare_shell_cmd(cmd->argv);
 417         }
 418
 419         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 420                                   fhin, fhout, fherr);
 421         failed_errno = errno;
 422         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 423                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 424         if (cmd->clean_on_exit && cmd->pid >= 0)
 425                 mark_child_for_cleanup(cmd->pid);
 426
 427         if (cmd->env)
 428                 free_environ(env);
 429         if (cmd->git_cmd)
 430                 free(cmd->argv);
 431
 432         cmd->argv = sargv;
 433         if (fhin != 0)
 434                 close(fhin);
 435         if (fhout != 1)
 436                 close(fhout);
 437         if (fherr != 2)
 438                 close(fherr);
 439 }
 440 #endif
 441
 442         if (cmd->pid < 0) {
 443                 if (need_in)
 444                         close_pair(fdin);
 445                 else if (cmd->in)
 446                         close(cmd->in);
 447                 if (need_out)
 448                         close_pair(fdout);
 449                 else if (cmd->out)
 450                         close(cmd->out);
 451                 if (need_err)
 452                         close_pair(fderr);
 453                 else if (cmd->err)
 454                         close(cmd->err);
 455                 errno = failed_errno;
 456                 return -1;
 457         }
 458
 459         if (need_in)
 460                 close(fdin[0]);
 461         else if (cmd->in)
 462                 close(cmd->in);
 463
 464         if (need_out)
 465                 close(fdout[1]);
 466         else if (cmd->out)
 467                 close(cmd->out);
 468
 469         if (need_err)
 470                 close(fderr[1]);
 471         else if (cmd->err)
 472                 close(cmd->err);
 473
 474         return 0;
 475 }
 476
 477 int finish_command(struct child_process *cmd)
 478 {
 479         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 480 }
 481
 482 int run_command(struct child_process *cmd)
 483 {
 484         int code = start_command(cmd);
 485         if (code)
 486                 return code;
 487         return finish_command(cmd);
 488 }
 489
 490 static void prepare_run_command_v_opt(struct child_process *cmd,
 491                                       const char **argv,
 492                                       int opt)
 493 {
 494         memset(cmd, 0, sizeof(*cmd));
 495         cmd->argv = argv;
 496         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 497         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 498         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 499         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 500         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 501 }
 502
 503 int run_command_v_opt(const char **argv, int opt)
 504 {
 505         struct child_process cmd;
 506         prepare_run_command_v_opt(&cmd, argv, opt);
 507         return run_command(&cmd);
 508 }
 509
 510 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 511 {
 512         struct child_process cmd;
 513         prepare_run_command_v_opt(&cmd, argv, opt);
 514         cmd.dir = dir;
 515         cmd.env = env;
 516         return run_command(&cmd);
 517 }
 518
 519 #ifndef NO_PTHREADS
 520 static pthread_t main_thread;
 521 static int main_thread_set;
 522 static pthread_key_t async_key;
 523
 524 static void *run_thread(void *data)
 525 {
 526         struct async *async = data;
 527         intptr_t ret;
 528
 529         pthread_setspecific(async_key, async);
 530         ret = async->proc(async->proc_in, async->proc_out, async->data);
 531         return (void *)ret;
 532 }
 533
 534 static NORETURN void die_async(const char *err, va_list params)
 535 {
 536         vreportf("fatal: ", err, params);
 537
 538         if (!pthread_equal(main_thread, pthread_self())) {
 539                 struct async *async = pthread_getspecific(async_key);
 540                 if (async->proc_in >= 0)
 541                         close(async->proc_in);
 542                 if (async->proc_out >= 0)
 543                         close(async->proc_out);
 544                 pthread_exit((void *)128);
 545         }
 546
 547         exit(128);
 548 }
 549 #endif
 550
 551 int start_async(struct async *async)
 552 {
 553         int need_in, need_out;
 554         int fdin[2], fdout[2];
 555         int proc_in, proc_out;
 556
 557         need_in = async->in < 0;
 558         if (need_in) {
 559                 if (pipe(fdin) < 0) {
 560                         if (async->out > 0)
 561                                 close(async->out);
 562                         return error("cannot create pipe: %s", strerror(errno));
 563                 }
 564                 async->in = fdin[1];
 565         }
 566
 567         need_out = async->out < 0;
 568         if (need_out) {
 569                 if (pipe(fdout) < 0) {
 570                         if (need_in)
 571                                 close_pair(fdin);
 572                         else if (async->in)
 573                                 close(async->in);
 574                         return error("cannot create pipe: %s", strerror(errno));
 575                 }
 576                 async->out = fdout[0];
 577         }
 578
 579         if (need_in)
 580                 proc_in = fdin[0];
 581         else if (async->in)
 582                 proc_in = async->in;
 583         else
 584                 proc_in = -1;
 585
 586         if (need_out)
 587                 proc_out = fdout[1];
 588         else if (async->out)
 589                 proc_out = async->out;
 590         else
 591                 proc_out = -1;
 592
 593 #ifdef NO_PTHREADS
 594         /* Flush stdio before fork() to avoid cloning buffers */
 595         fflush(NULL);
 596
 597         async->pid = fork();
 598         if (async->pid < 0) {
 599                 error("fork (async) failed: %s", strerror(errno));
 600                 goto error;
 601         }
 602         if (!async->pid) {
 603                 if (need_in)
 604                         close(fdin[1]);
 605                 if (need_out)
 606                         close(fdout[0]);
 607                 exit(!!async->proc(proc_in, proc_out, async->data));
 608         }
 609
 610         mark_child_for_cleanup(async->pid);
 611
 612         if (need_in)
 613                 close(fdin[0]);
 614         else if (async->in)
 615                 close(async->in);
 616
 617         if (need_out)
 618                 close(fdout[1]);
 619         else if (async->out)
 620                 close(async->out);
 621 #else
 622         if (!main_thread_set) {
 623                 /*
 624                  * We assume that the first time that start_async is called
 625                  * it is from the main thread.
 626                  */
 627                 main_thread_set = 1;
 628                 main_thread = pthread_self();
 629                 pthread_key_create(&async_key, NULL);
 630                 set_die_routine(die_async);
 631         }
 632
 633         if (proc_in >= 0)
 634                 set_cloexec(proc_in);
 635         if (proc_out >= 0)
 636                 set_cloexec(proc_out);
 637         async->proc_in = proc_in;
 638         async->proc_out = proc_out;
 639         {
 640                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 641                 if (err) {
 642                         error("cannot create thread: %s", strerror(err));
 643                         goto error;
 644                 }
 645         }
 646 #endif
 647         return 0;
 648
 649 error:
 650         if (need_in)
 651                 close_pair(fdin);
 652         else if (async->in)
 653                 close(async->in);
 654
 655         if (need_out)
 656                 close_pair(fdout);
 657         else if (async->out)
 658                 close(async->out);
 659         return -1;
 660 }
 661
 662 int finish_async(struct async *async)
 663 {
 664 #ifdef NO_PTHREADS
 665         return wait_or_whine(async->pid, "child process", 0);
 666 #else
 667         void *ret = (void *)(intptr_t)(-1);
 668
 669         if (pthread_join(async->tid, &ret))
 670                 error("pthread_join failed");
 671         return (int)(intptr_t)ret;
 672 #endif
 673 }
 674
 675 int run_hook(const char *index_file, const char *name, ...)
 676 {
 677         struct child_process hook;
 678         struct argv_array argv = ARGV_ARRAY_INIT;
 679         const char *p, *env[2];
 680         char index[PATH_MAX];
 681         va_list args;
 682         int ret;
 683
 684         if (access(git_path("hooks/%s", name), X_OK) < 0)
 685                 return 0;
 686
 687         va_start(args, name);
 688         argv_array_push(&argv, git_path("hooks/%s", name));
 689         while ((p = va_arg(args, const char *)))
 690                 argv_array_push(&argv, p);
 691         va_end(args);
 692
 693         memset(&hook, 0, sizeof(hook));
 694         hook.argv = argv.argv;
 695         hook.no_stdin = 1;
 696         hook.stdout_to_stderr = 1;
 697         if (index_file) {
 698                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 699                 env[0] = index;
 700                 env[1] = NULL;
 701                 hook.env = env;
 702         }
 703
 704         ret = run_command(&hook);
 705         argv_array_clear(&argv);
 706         return ret;
 707 }