run-command.c

   1 #include "cache.h"
   2 #include "run-command.h"
   3 #include "exec_cmd.h"
   4
   5 static inline void close_pair(int fd[2])
   6 {
   7         close(fd[0]);
   8         close(fd[1]);
   9 }
  10
  11 #ifndef WIN32
  12 static inline void dup_devnull(int to)
  13 {
  14         int fd = open("/dev/null", O_RDWR);
  15         dup2(fd, to);
  16         close(fd);
  17 }
  18 #endif
  19
  20 static const char **prepare_shell_cmd(const char **argv)
  21 {
  22         int argc, nargc = 0;
  23         const char **nargv;
  24
  25         for (argc = 0; argv[argc]; argc++)
  26                 ; /* just counting */
  27         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
  28         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
  29
  30         if (argc < 1)
  31                 die("BUG: shell command is empty");
  32
  33         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
  34                 nargv[nargc++] = "sh";
  35                 nargv[nargc++] = "-c";
  36
  37                 if (argc < 2)
  38                         nargv[nargc++] = argv[0];
  39                 else {
  40                         struct strbuf arg0 = STRBUF_INIT;
  41                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
  42                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
  43                 }
  44         }
  45
  46         for (argc = 0; argv[argc]; argc++)
  47                 nargv[nargc++] = argv[argc];
  48         nargv[nargc] = NULL;
  49
  50         return nargv;
  51 }
  52
  53 #ifndef WIN32
  54 static int execv_shell_cmd(const char **argv)
  55 {
  56         const char **nargv = prepare_shell_cmd(argv);
  57         trace_argv_printf(nargv, "trace: exec:");
  58         execvp(nargv[0], (char **)nargv);
  59         free(nargv);
  60         return -1;
  61 }
  62 #endif
  63
  64 #ifndef WIN32
  65 static int child_err = 2;
  66 static int child_notifier = -1;
  67
  68 static void notify_parent(void)
  69 {
  70         /*
  71          * execvp failed.  If possible, we'd like to let start_command
  72          * know, so failures like ENOENT can be handled right away; but
  73          * otherwise, finish_command will still report the error.
  74          */
  75         xwrite(child_notifier, "", 1);
  76 }
  77
  78 static NORETURN void die_child(const char *err, va_list params)
  79 {
  80         vwritef(child_err, "fatal: ", err, params);
  81         exit(128);
  82 }
  83
  84 static void error_child(const char *err, va_list params)
  85 {
  86         vwritef(child_err, "error: ", err, params);
  87 }
  88 #endif
  89
  90 static inline void set_cloexec(int fd)
  91 {
  92         int flags = fcntl(fd, F_GETFD);
  93         if (flags >= 0)
  94                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
  95 }
  96
  97 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
  98 {
  99         int status, code = -1;
 100         pid_t waiting;
 101         int failed_errno = 0;
 102
 103         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 104                 ;       /* nothing */
 105
 106         if (waiting < 0) {
 107                 failed_errno = errno;
 108                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 109         } else if (waiting != pid) {
 110                 error("waitpid is confused (%s)", argv0);
 111         } else if (WIFSIGNALED(status)) {
 112                 code = WTERMSIG(status);
 113                 error("%s died of signal %d", argv0, code);
 114                 /*
 115                  * This return value is chosen so that code & 0xff
 116                  * mimics the exit code that a POSIX shell would report for
 117                  * a program that died from this signal.
 118                  */
 119                 code -= 128;
 120         } else if (WIFEXITED(status)) {
 121                 code = WEXITSTATUS(status);
 122                 /*
 123                  * Convert special exit code when execvp failed.
 124                  */
 125                 if (code == 127) {
 126                         code = -1;
 127                         failed_errno = ENOENT;
 128                 }
 129         } else {
 130                 error("waitpid is confused (%s)", argv0);
 131         }
 132         errno = failed_errno;
 133         return code;
 134 }
 135
 136 int start_command(struct child_process *cmd)
 137 {
 138         int need_in, need_out, need_err;
 139         int fdin[2], fdout[2], fderr[2];
 140         int failed_errno = failed_errno;
 141
 142         /*
 143          * In case of errors we must keep the promise to close FDs
 144          * that have been passed in via ->in and ->out.
 145          */
 146
 147         need_in = !cmd->no_stdin && cmd->in < 0;
 148         if (need_in) {
 149                 if (pipe(fdin) < 0) {
 150                         failed_errno = errno;
 151                         if (cmd->out > 0)
 152                                 close(cmd->out);
 153                         goto fail_pipe;
 154                 }
 155                 cmd->in = fdin[1];
 156         }
 157
 158         need_out = !cmd->no_stdout
 159                 && !cmd->stdout_to_stderr
 160                 && cmd->out < 0;
 161         if (need_out) {
 162                 if (pipe(fdout) < 0) {
 163                         failed_errno = errno;
 164                         if (need_in)
 165                                 close_pair(fdin);
 166                         else if (cmd->in)
 167                                 close(cmd->in);
 168                         goto fail_pipe;
 169                 }
 170                 cmd->out = fdout[0];
 171         }
 172
 173         need_err = !cmd->no_stderr && cmd->err < 0;
 174         if (need_err) {
 175                 if (pipe(fderr) < 0) {
 176                         failed_errno = errno;
 177                         if (need_in)
 178                                 close_pair(fdin);
 179                         else if (cmd->in)
 180                                 close(cmd->in);
 181                         if (need_out)
 182                                 close_pair(fdout);
 183                         else if (cmd->out)
 184                                 close(cmd->out);
 185 fail_pipe:
 186                         error("cannot create pipe for %s: %s",
 187                                 cmd->argv[0], strerror(failed_errno));
 188                         errno = failed_errno;
 189                         return -1;
 190                 }
 191                 cmd->err = fderr[0];
 192         }
 193
 194         trace_argv_printf(cmd->argv, "trace: run_command:");
 195         fflush(NULL);
 196
 197 #ifndef WIN32
 198 {
 199         int notify_pipe[2];
 200         if (pipe(notify_pipe))
 201                 notify_pipe[0] = notify_pipe[1] = -1;
 202
 203         cmd->pid = fork();
 204         if (!cmd->pid) {
 205                 /*
 206                  * Redirect the channel to write syscall error messages to
 207                  * before redirecting the process's stderr so that all die()
 208                  * in subsequent call paths use the parent's stderr.
 209                  */
 210                 if (cmd->no_stderr || need_err) {
 211                         child_err = dup(2);
 212                         set_cloexec(child_err);
 213                 }
 214                 set_die_routine(die_child);
 215                 set_error_routine(error_child);
 216
 217                 close(notify_pipe[0]);
 218                 set_cloexec(notify_pipe[1]);
 219                 child_notifier = notify_pipe[1];
 220                 atexit(notify_parent);
 221
 222                 if (cmd->no_stdin)
 223                         dup_devnull(0);
 224                 else if (need_in) {
 225                         dup2(fdin[0], 0);
 226                         close_pair(fdin);
 227                 } else if (cmd->in) {
 228                         dup2(cmd->in, 0);
 229                         close(cmd->in);
 230                 }
 231
 232                 if (cmd->no_stderr)
 233                         dup_devnull(2);
 234                 else if (need_err) {
 235                         dup2(fderr[1], 2);
 236                         close_pair(fderr);
 237                 } else if (cmd->err > 1) {
 238                         dup2(cmd->err, 2);
 239                         close(cmd->err);
 240                 }
 241
 242                 if (cmd->no_stdout)
 243                         dup_devnull(1);
 244                 else if (cmd->stdout_to_stderr)
 245                         dup2(2, 1);
 246                 else if (need_out) {
 247                         dup2(fdout[1], 1);
 248                         close_pair(fdout);
 249                 } else if (cmd->out > 1) {
 250                         dup2(cmd->out, 1);
 251                         close(cmd->out);
 252                 }
 253
 254                 if (cmd->dir && chdir(cmd->dir))
 255                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 256                             cmd->dir);
 257                 if (cmd->env) {
 258                         for (; *cmd->env; cmd->env++) {
 259                                 if (strchr(*cmd->env, '='))
 260                                         putenv((char *)*cmd->env);
 261                                 else
 262                                         unsetenv(*cmd->env);
 263                         }
 264                 }
 265                 if (cmd->preexec_cb) {
 266                         /*
 267                          * We cannot predict what the pre-exec callback does.
 268                          * Forgo parent notification.
 269                          */
 270                         close(child_notifier);
 271                         child_notifier = -1;
 272
 273                         cmd->preexec_cb();
 274                 }
 275                 if (cmd->git_cmd) {
 276                         execv_git_cmd(cmd->argv);
 277                 } else if (cmd->use_shell) {
 278                         execv_shell_cmd(cmd->argv);
 279                 } else {
 280                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 281                 }
 282                 if (errno == ENOENT) {
 283                         if (!cmd->silent_exec_failure)
 284                                 error("cannot run %s: %s", cmd->argv[0],
 285                                         strerror(ENOENT));
 286                         exit(127);
 287                 } else {
 288                         die_errno("cannot exec '%s'", cmd->argv[0]);
 289                 }
 290         }
 291         if (cmd->pid < 0)
 292                 error("cannot fork() for %s: %s", cmd->argv[0],
 293                         strerror(failed_errno = errno));
 294
 295         /*
 296          * Wait for child's execvp. If the execvp succeeds (or if fork()
 297          * failed), EOF is seen immediately by the parent. Otherwise, the
 298          * child process sends a single byte.
 299          * Note that use of this infrastructure is completely advisory,
 300          * therefore, we keep error checks minimal.
 301          */
 302         close(notify_pipe[1]);
 303         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 304                 /*
 305                  * At this point we know that fork() succeeded, but execvp()
 306                  * failed. Errors have been reported to our stderr.
 307                  */
 308                 wait_or_whine(cmd->pid, cmd->argv[0],
 309                               cmd->silent_exec_failure);
 310                 failed_errno = errno;
 311                 cmd->pid = -1;
 312         }
 313         close(notify_pipe[0]);
 314 }
 315 #else
 316 {
 317         int fhin = 0, fhout = 1, fherr = 2;
 318         const char **sargv = cmd->argv;
 319         char **env = environ;
 320
 321         if (cmd->no_stdin)
 322                 fhin = open("/dev/null", O_RDWR);
 323         else if (need_in)
 324                 fhin = dup(fdin[0]);
 325         else if (cmd->in)
 326                 fhin = dup(cmd->in);
 327
 328         if (cmd->no_stderr)
 329                 fherr = open("/dev/null", O_RDWR);
 330         else if (need_err)
 331                 fherr = dup(fderr[1]);
 332         else if (cmd->err > 2)
 333                 fherr = dup(cmd->err);
 334
 335         if (cmd->no_stdout)
 336                 fhout = open("/dev/null", O_RDWR);
 337         else if (cmd->stdout_to_stderr)
 338                 fhout = dup(fherr);
 339         else if (need_out)
 340                 fhout = dup(fdout[1]);
 341         else if (cmd->out > 1)
 342                 fhout = dup(cmd->out);
 343
 344         if (cmd->env)
 345                 env = make_augmented_environ(cmd->env);
 346
 347         if (cmd->git_cmd) {
 348                 cmd->argv = prepare_git_cmd(cmd->argv);
 349         } else if (cmd->use_shell) {
 350                 cmd->argv = prepare_shell_cmd(cmd->argv);
 351         }
 352
 353         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 354                                   fhin, fhout, fherr);
 355         failed_errno = errno;
 356         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 357                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 358
 359         if (cmd->env)
 360                 free_environ(env);
 361         if (cmd->git_cmd)
 362                 free(cmd->argv);
 363
 364         cmd->argv = sargv;
 365         if (fhin != 0)
 366                 close(fhin);
 367         if (fhout != 1)
 368                 close(fhout);
 369         if (fherr != 2)
 370                 close(fherr);
 371 }
 372 #endif
 373
 374         if (cmd->pid < 0) {
 375                 if (need_in)
 376                         close_pair(fdin);
 377                 else if (cmd->in)
 378                         close(cmd->in);
 379                 if (need_out)
 380                         close_pair(fdout);
 381                 else if (cmd->out)
 382                         close(cmd->out);
 383                 if (need_err)
 384                         close_pair(fderr);
 385                 else if (cmd->err)
 386                         close(cmd->err);
 387                 errno = failed_errno;
 388                 return -1;
 389         }
 390
 391         if (need_in)
 392                 close(fdin[0]);
 393         else if (cmd->in)
 394                 close(cmd->in);
 395
 396         if (need_out)
 397                 close(fdout[1]);
 398         else if (cmd->out)
 399                 close(cmd->out);
 400
 401         if (need_err)
 402                 close(fderr[1]);
 403         else if (cmd->err)
 404                 close(cmd->err);
 405
 406         return 0;
 407 }
 408
 409 int finish_command(struct child_process *cmd)
 410 {
 411         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 412 }
 413
 414 int run_command(struct child_process *cmd)
 415 {
 416         int code = start_command(cmd);
 417         if (code)
 418                 return code;
 419         return finish_command(cmd);
 420 }
 421
 422 static void prepare_run_command_v_opt(struct child_process *cmd,
 423                                       const char **argv,
 424                                       int opt)
 425 {
 426         memset(cmd, 0, sizeof(*cmd));
 427         cmd->argv = argv;
 428         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 429         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 430         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 431         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 432         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 433 }
 434
 435 int run_command_v_opt(const char **argv, int opt)
 436 {
 437         struct child_process cmd;
 438         prepare_run_command_v_opt(&cmd, argv, opt);
 439         return run_command(&cmd);
 440 }
 441
 442 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 443 {
 444         struct child_process cmd;
 445         prepare_run_command_v_opt(&cmd, argv, opt);
 446         cmd.dir = dir;
 447         cmd.env = env;
 448         return run_command(&cmd);
 449 }
 450
 451 #ifndef NO_PTHREADS
 452 static pthread_t main_thread;
 453 static int main_thread_set;
 454 static pthread_key_t async_key;
 455
 456 static void *run_thread(void *data)
 457 {
 458         struct async *async = data;
 459         intptr_t ret;
 460
 461         pthread_setspecific(async_key, async);
 462         ret = async->proc(async->proc_in, async->proc_out, async->data);
 463         return (void *)ret;
 464 }
 465
 466 static NORETURN void die_async(const char *err, va_list params)
 467 {
 468         vreportf("fatal: ", err, params);
 469
 470         if (!pthread_equal(main_thread, pthread_self())) {
 471                 struct async *async = pthread_getspecific(async_key);
 472                 if (async->proc_in >= 0)
 473                         close(async->proc_in);
 474                 if (async->proc_out >= 0)
 475                         close(async->proc_out);
 476                 pthread_exit((void *)128);
 477         }
 478
 479         exit(128);
 480 }
 481 #endif
 482
 483 int start_async(struct async *async)
 484 {
 485         int need_in, need_out;
 486         int fdin[2], fdout[2];
 487         int proc_in, proc_out;
 488
 489         need_in = async->in < 0;
 490         if (need_in) {
 491                 if (pipe(fdin) < 0) {
 492                         if (async->out > 0)
 493                                 close(async->out);
 494                         return error("cannot create pipe: %s", strerror(errno));
 495                 }
 496                 async->in = fdin[1];
 497         }
 498
 499         need_out = async->out < 0;
 500         if (need_out) {
 501                 if (pipe(fdout) < 0) {
 502                         if (need_in)
 503                                 close_pair(fdin);
 504                         else if (async->in)
 505                                 close(async->in);
 506                         return error("cannot create pipe: %s", strerror(errno));
 507                 }
 508                 async->out = fdout[0];
 509         }
 510
 511         if (need_in)
 512                 proc_in = fdin[0];
 513         else if (async->in)
 514                 proc_in = async->in;
 515         else
 516                 proc_in = -1;
 517
 518         if (need_out)
 519                 proc_out = fdout[1];
 520         else if (async->out)
 521                 proc_out = async->out;
 522         else
 523                 proc_out = -1;
 524
 525 #ifdef NO_PTHREADS
 526         /* Flush stdio before fork() to avoid cloning buffers */
 527         fflush(NULL);
 528
 529         async->pid = fork();
 530         if (async->pid < 0) {
 531                 error("fork (async) failed: %s", strerror(errno));
 532                 goto error;
 533         }
 534         if (!async->pid) {
 535                 if (need_in)
 536                         close(fdin[1]);
 537                 if (need_out)
 538                         close(fdout[0]);
 539                 exit(!!async->proc(proc_in, proc_out, async->data));
 540         }
 541
 542         if (need_in)
 543                 close(fdin[0]);
 544         else if (async->in)
 545                 close(async->in);
 546
 547         if (need_out)
 548                 close(fdout[1]);
 549         else if (async->out)
 550                 close(async->out);
 551 #else
 552         if (!main_thread_set) {
 553                 /*
 554                  * We assume that the first time that start_async is called
 555                  * it is from the main thread.
 556                  */
 557                 main_thread_set = 1;
 558                 main_thread = pthread_self();
 559                 pthread_key_create(&async_key, NULL);
 560                 set_die_routine(die_async);
 561         }
 562
 563         if (proc_in >= 0)
 564                 set_cloexec(proc_in);
 565         if (proc_out >= 0)
 566                 set_cloexec(proc_out);
 567         async->proc_in = proc_in;
 568         async->proc_out = proc_out;
 569         {
 570                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 571                 if (err) {
 572                         error("cannot create thread: %s", strerror(err));
 573                         goto error;
 574                 }
 575         }
 576 #endif
 577         return 0;
 578
 579 error:
 580         if (need_in)
 581                 close_pair(fdin);
 582         else if (async->in)
 583                 close(async->in);
 584
 585         if (need_out)
 586                 close_pair(fdout);
 587         else if (async->out)
 588                 close(async->out);
 589         return -1;
 590 }
 591
 592 int finish_async(struct async *async)
 593 {
 594 #ifdef NO_PTHREADS
 595         return wait_or_whine(async->pid, "child process", 0);
 596 #else
 597         void *ret = (void *)(intptr_t)(-1);
 598
 599         if (pthread_join(async->tid, &ret))
 600                 error("pthread_join failed");
 601         return (int)(intptr_t)ret;
 602 #endif
 603 }
 604
 605 int run_hook(const char *index_file, const char *name, ...)
 606 {
 607         struct child_process hook;
 608         const char **argv = NULL, *env[2];
 609         char index[PATH_MAX];
 610         va_list args;
 611         int ret;
 612         size_t i = 0, alloc = 0;
 613
 614         if (access(git_path("hooks/%s", name), X_OK) < 0)
 615                 return 0;
 616
 617         va_start(args, name);
 618         ALLOC_GROW(argv, i + 1, alloc);
 619         argv[i++] = git_path("hooks/%s", name);
 620         while (argv[i-1]) {
 621                 ALLOC_GROW(argv, i + 1, alloc);
 622                 argv[i++] = va_arg(args, const char *);
 623         }
 624         va_end(args);
 625
 626         memset(&hook, 0, sizeof(hook));
 627         hook.argv = argv;
 628         hook.no_stdin = 1;
 629         hook.stdout_to_stderr = 1;
 630         if (index_file) {
 631                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 632                 env[0] = index;
 633                 env[1] = NULL;
 634                 hook.env = env;
 635         }
 636
 637         ret = run_command(&hook);
 638         free(argv);
 639         return ret;
 640 }