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