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         ssize_t unused;
  71         unused = write(child_notifier, "", 1);
  72 }
  73
  74 static NORETURN void die_child(const char *err, va_list params)
  75 {
  76         char msg[4096];
  77         ssize_t unused;
  78         int len = vsnprintf(msg, sizeof(msg), err, params);
  79         if (len > sizeof(msg))
  80                 len = sizeof(msg);
  81
  82         unused = write(child_err, "fatal: ", 7);
  83         unused = write(child_err, msg, len);
  84         unused = write(child_err, "\n", 1);
  85         exit(128);
  86 }
  87 #endif
  88
  89 static inline void set_cloexec(int fd)
  90 {
  91         int flags = fcntl(fd, F_GETFD);
  92         if (flags >= 0)
  93                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
  94 }
  95
  96 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
  97 {
  98         int status, code = -1;
  99         pid_t waiting;
 100         int failed_errno = 0;
 101
 102         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 103                 ;       /* nothing */
 104
 105         if (waiting < 0) {
 106                 failed_errno = errno;
 107                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 108         } else if (waiting != pid) {
 109                 error("waitpid is confused (%s)", argv0);
 110         } else if (WIFSIGNALED(status)) {
 111                 code = WTERMSIG(status);
 112                 error("%s died of signal %d", argv0, code);
 113                 /*
 114                  * This return value is chosen so that code & 0xff
 115                  * mimics the exit code that a POSIX shell would report for
 116                  * a program that died from this signal.
 117                  */
 118                 code -= 128;
 119         } else if (WIFEXITED(status)) {
 120                 code = WEXITSTATUS(status);
 121                 /*
 122                  * Convert special exit code when execvp failed.
 123                  */
 124                 if (code == 127) {
 125                         code = -1;
 126                         failed_errno = ENOENT;
 127                         if (!silent_exec_failure)
 128                                 error("cannot run %s: %s", argv0,
 129                                         strerror(ENOENT));
 130                 }
 131         } else {
 132                 error("waitpid is confused (%s)", argv0);
 133         }
 134         errno = failed_errno;
 135         return code;
 136 }
 137
 138 int start_command(struct child_process *cmd)
 139 {
 140         int need_in, need_out, need_err;
 141         int fdin[2], fdout[2], fderr[2];
 142         int failed_errno = failed_errno;
 143
 144         /*
 145          * In case of errors we must keep the promise to close FDs
 146          * that have been passed in via ->in and ->out.
 147          */
 148
 149         need_in = !cmd->no_stdin && cmd->in < 0;
 150         if (need_in) {
 151                 if (pipe(fdin) < 0) {
 152                         failed_errno = errno;
 153                         if (cmd->out > 0)
 154                                 close(cmd->out);
 155                         goto fail_pipe;
 156                 }
 157                 cmd->in = fdin[1];
 158         }
 159
 160         need_out = !cmd->no_stdout
 161                 && !cmd->stdout_to_stderr
 162                 && cmd->out < 0;
 163         if (need_out) {
 164                 if (pipe(fdout) < 0) {
 165                         failed_errno = errno;
 166                         if (need_in)
 167                                 close_pair(fdin);
 168                         else if (cmd->in)
 169                                 close(cmd->in);
 170                         goto fail_pipe;
 171                 }
 172                 cmd->out = fdout[0];
 173         }
 174
 175         need_err = !cmd->no_stderr && cmd->err < 0;
 176         if (need_err) {
 177                 if (pipe(fderr) < 0) {
 178                         failed_errno = errno;
 179                         if (need_in)
 180                                 close_pair(fdin);
 181                         else if (cmd->in)
 182                                 close(cmd->in);
 183                         if (need_out)
 184                                 close_pair(fdout);
 185                         else if (cmd->out)
 186                                 close(cmd->out);
 187 fail_pipe:
 188                         error("cannot create pipe for %s: %s",
 189                                 cmd->argv[0], strerror(failed_errno));
 190                         errno = failed_errno;
 191                         return -1;
 192                 }
 193                 cmd->err = fderr[0];
 194         }
 195
 196         trace_argv_printf(cmd->argv, "trace: run_command:");
 197
 198 #ifndef WIN32
 199 {
 200         int notify_pipe[2];
 201         if (pipe(notify_pipe))
 202                 notify_pipe[0] = notify_pipe[1] = -1;
 203
 204         fflush(NULL);
 205         cmd->pid = fork();
 206         if (!cmd->pid) {
 207                 /*
 208                  * Redirect the channel to write syscall error messages to
 209                  * before redirecting the process's stderr so that all die()
 210                  * in subsequent call paths use the parent's stderr.
 211                  */
 212                 if (cmd->no_stderr || need_err) {
 213                         child_err = dup(2);
 214                         set_cloexec(child_err);
 215                 }
 216                 set_die_routine(die_child);
 217
 218                 close(notify_pipe[0]);
 219                 set_cloexec(notify_pipe[1]);
 220                 child_notifier = notify_pipe[1];
 221                 atexit(notify_parent);
 222
 223                 if (cmd->no_stdin)
 224                         dup_devnull(0);
 225                 else if (need_in) {
 226                         dup2(fdin[0], 0);
 227                         close_pair(fdin);
 228                 } else if (cmd->in) {
 229                         dup2(cmd->in, 0);
 230                         close(cmd->in);
 231                 }
 232
 233                 if (cmd->no_stderr)
 234                         dup_devnull(2);
 235                 else if (need_err) {
 236                         dup2(fderr[1], 2);
 237                         close_pair(fderr);
 238                 } else if (cmd->err > 1) {
 239                         dup2(cmd->err, 2);
 240                         close(cmd->err);
 241                 }
 242
 243                 if (cmd->no_stdout)
 244                         dup_devnull(1);
 245                 else if (cmd->stdout_to_stderr)
 246                         dup2(2, 1);
 247                 else if (need_out) {
 248                         dup2(fdout[1], 1);
 249                         close_pair(fdout);
 250                 } else if (cmd->out > 1) {
 251                         dup2(cmd->out, 1);
 252                         close(cmd->out);
 253                 }
 254
 255                 if (cmd->dir && chdir(cmd->dir))
 256                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 257                             cmd->dir);
 258                 if (cmd->env) {
 259                         for (; *cmd->env; cmd->env++) {
 260                                 if (strchr(*cmd->env, '='))
 261                                         putenv((char *)*cmd->env);
 262                                 else
 263                                         unsetenv(*cmd->env);
 264                         }
 265                 }
 266                 if (cmd->preexec_cb) {
 267                         /*
 268                          * We cannot predict what the pre-exec callback does.
 269                          * Forgo parent notification.
 270                          */
 271                         close(child_notifier);
 272                         child_notifier = -1;
 273
 274                         cmd->preexec_cb();
 275                 }
 276                 if (cmd->git_cmd) {
 277                         execv_git_cmd(cmd->argv);
 278                 } else if (cmd->use_shell) {
 279                         execv_shell_cmd(cmd->argv);
 280                 } else {
 281                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 282                 }
 283                 /*
 284                  * Do not check for cmd->silent_exec_failure; the parent
 285                  * process will check it when it sees this exit code.
 286                  */
 287                 if (errno == ENOENT)
 288                         exit(127);
 289                 else
 290                         die_errno("cannot exec '%s'", cmd->argv[0]);
 291         }
 292         if (cmd->pid < 0)
 293                 error("cannot fork() for %s: %s", cmd->argv[0],
 294                         strerror(failed_errno = errno));
 295
 296         /*
 297          * Wait for child's execvp. If the execvp succeeds (or if fork()
 298          * failed), EOF is seen immediately by the parent. Otherwise, the
 299          * child process sends a single byte.
 300          * Note that use of this infrastructure is completely advisory,
 301          * therefore, we keep error checks minimal.
 302          */
 303         close(notify_pipe[1]);
 304         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 305                 /*
 306                  * At this point we know that fork() succeeded, but execvp()
 307                  * failed. Errors have been reported to our stderr.
 308                  */
 309                 wait_or_whine(cmd->pid, cmd->argv[0],
 310                               cmd->silent_exec_failure);
 311                 failed_errno = errno;
 312                 cmd->pid = -1;
 313         }
 314         close(notify_pipe[0]);
 315 }
 316 #else
 317 {
 318         int fhin = 0, fhout = 1, fherr = 2;
 319         const char **sargv = cmd->argv;
 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->git_cmd) {
 345                 cmd->argv = prepare_git_cmd(cmd->argv);
 346         } else if (cmd->use_shell) {
 347                 cmd->argv = prepare_shell_cmd(cmd->argv);
 348         }
 349
 350         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
 351                                 cmd->dir, fhin, fhout, fherr);
 352         failed_errno = errno;
 353         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 354                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 355
 356         if (cmd->git_cmd)
 357                 free(cmd->argv);
 358
 359         cmd->argv = sargv;
 360         if (fhin != 0)
 361                 close(fhin);
 362         if (fhout != 1)
 363                 close(fhout);
 364         if (fherr != 2)
 365                 close(fherr);
 366 }
 367 #endif
 368
 369         if (cmd->pid < 0) {
 370                 if (need_in)
 371                         close_pair(fdin);
 372                 else if (cmd->in)
 373                         close(cmd->in);
 374                 if (need_out)
 375                         close_pair(fdout);
 376                 else if (cmd->out)
 377                         close(cmd->out);
 378                 if (need_err)
 379                         close_pair(fderr);
 380                 else if (cmd->err)
 381                         close(cmd->err);
 382                 errno = failed_errno;
 383                 return -1;
 384         }
 385
 386         if (need_in)
 387                 close(fdin[0]);
 388         else if (cmd->in)
 389                 close(cmd->in);
 390
 391         if (need_out)
 392                 close(fdout[1]);
 393         else if (cmd->out)
 394                 close(cmd->out);
 395
 396         if (need_err)
 397                 close(fderr[1]);
 398         else if (cmd->err)
 399                 close(cmd->err);
 400
 401         return 0;
 402 }
 403
 404 int finish_command(struct child_process *cmd)
 405 {
 406         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 407 }
 408
 409 int run_command(struct child_process *cmd)
 410 {
 411         int code = start_command(cmd);
 412         if (code)
 413                 return code;
 414         return finish_command(cmd);
 415 }
 416
 417 static void prepare_run_command_v_opt(struct child_process *cmd,
 418                                       const char **argv,
 419                                       int opt)
 420 {
 421         memset(cmd, 0, sizeof(*cmd));
 422         cmd->argv = argv;
 423         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 424         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 425         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 426         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 427         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 428 }
 429
 430 int run_command_v_opt(const char **argv, int opt)
 431 {
 432         struct child_process cmd;
 433         prepare_run_command_v_opt(&cmd, argv, opt);
 434         return run_command(&cmd);
 435 }
 436
 437 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 438 {
 439         struct child_process cmd;
 440         prepare_run_command_v_opt(&cmd, argv, opt);
 441         cmd.dir = dir;
 442         cmd.env = env;
 443         return run_command(&cmd);
 444 }
 445
 446 #ifndef NO_PTHREADS
 447 static pthread_t main_thread;
 448 static int main_thread_set;
 449 static pthread_key_t async_key;
 450
 451 static void *run_thread(void *data)
 452 {
 453         struct async *async = data;
 454         intptr_t ret;
 455
 456         pthread_setspecific(async_key, async);
 457         ret = async->proc(async->proc_in, async->proc_out, async->data);
 458         return (void *)ret;
 459 }
 460
 461 static NORETURN void die_async(const char *err, va_list params)
 462 {
 463         vreportf("fatal: ", err, params);
 464
 465         if (!pthread_equal(main_thread, pthread_self())) {
 466                 struct async *async = pthread_getspecific(async_key);
 467                 if (async->proc_in >= 0)
 468                         close(async->proc_in);
 469                 if (async->proc_out >= 0)
 470                         close(async->proc_out);
 471                 pthread_exit((void *)128);
 472         }
 473
 474         exit(128);
 475 }
 476 #endif
 477
 478 int start_async(struct async *async)
 479 {
 480         int need_in, need_out;
 481         int fdin[2], fdout[2];
 482         int proc_in, proc_out;
 483
 484         need_in = async->in < 0;
 485         if (need_in) {
 486                 if (pipe(fdin) < 0) {
 487                         if (async->out > 0)
 488                                 close(async->out);
 489                         return error("cannot create pipe: %s", strerror(errno));
 490                 }
 491                 async->in = fdin[1];
 492         }
 493
 494         need_out = async->out < 0;
 495         if (need_out) {
 496                 if (pipe(fdout) < 0) {
 497                         if (need_in)
 498                                 close_pair(fdin);
 499                         else if (async->in)
 500                                 close(async->in);
 501                         return error("cannot create pipe: %s", strerror(errno));
 502                 }
 503                 async->out = fdout[0];
 504         }
 505
 506         if (need_in)
 507                 proc_in = fdin[0];
 508         else if (async->in)
 509                 proc_in = async->in;
 510         else
 511                 proc_in = -1;
 512
 513         if (need_out)
 514                 proc_out = fdout[1];
 515         else if (async->out)
 516                 proc_out = async->out;
 517         else
 518                 proc_out = -1;
 519
 520 #ifdef NO_PTHREADS
 521         /* Flush stdio before fork() to avoid cloning buffers */
 522         fflush(NULL);
 523
 524         async->pid = fork();
 525         if (async->pid < 0) {
 526                 error("fork (async) failed: %s", strerror(errno));
 527                 goto error;
 528         }
 529         if (!async->pid) {
 530                 if (need_in)
 531                         close(fdin[1]);
 532                 if (need_out)
 533                         close(fdout[0]);
 534                 exit(!!async->proc(proc_in, proc_out, async->data));
 535         }
 536
 537         if (need_in)
 538                 close(fdin[0]);
 539         else if (async->in)
 540                 close(async->in);
 541
 542         if (need_out)
 543                 close(fdout[1]);
 544         else if (async->out)
 545                 close(async->out);
 546 #else
 547         if (!main_thread_set) {
 548                 /*
 549                  * We assume that the first time that start_async is called
 550                  * it is from the main thread.
 551                  */
 552                 main_thread_set = 1;
 553                 main_thread = pthread_self();
 554                 pthread_key_create(&async_key, NULL);
 555                 set_die_routine(die_async);
 556         }
 557
 558         if (proc_in >= 0)
 559                 set_cloexec(proc_in);
 560         if (proc_out >= 0)
 561                 set_cloexec(proc_out);
 562         async->proc_in = proc_in;
 563         async->proc_out = proc_out;
 564         {
 565                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 566                 if (err) {
 567                         error("cannot create thread: %s", strerror(err));
 568                         goto error;
 569                 }
 570         }
 571 #endif
 572         return 0;
 573
 574 error:
 575         if (need_in)
 576                 close_pair(fdin);
 577         else if (async->in)
 578                 close(async->in);
 579
 580         if (need_out)
 581                 close_pair(fdout);
 582         else if (async->out)
 583                 close(async->out);
 584         return -1;
 585 }
 586
 587 int finish_async(struct async *async)
 588 {
 589 #ifdef NO_PTHREADS
 590         return wait_or_whine(async->pid, "child process", 0);
 591 #else
 592         void *ret = (void *)(intptr_t)(-1);
 593
 594         if (pthread_join(async->tid, &ret))
 595                 error("pthread_join failed");
 596         return (int)(intptr_t)ret;
 597 #endif
 598 }
 599
 600 int run_hook(const char *index_file, const char *name, ...)
 601 {
 602         struct child_process hook;
 603         const char **argv = NULL, *env[2];
 604         char index[PATH_MAX];
 605         va_list args;
 606         int ret;
 607         size_t i = 0, alloc = 0;
 608
 609         if (access(git_path("hooks/%s", name), X_OK) < 0)
 610                 return 0;
 611
 612         va_start(args, name);
 613         ALLOC_GROW(argv, i + 1, alloc);
 614         argv[i++] = git_path("hooks/%s", name);
 615         while (argv[i-1]) {
 616                 ALLOC_GROW(argv, i + 1, alloc);
 617                 argv[i++] = va_arg(args, const char *);
 618         }
 619         va_end(args);
 620
 621         memset(&hook, 0, sizeof(hook));
 622         hook.argv = argv;
 623         hook.no_stdin = 1;
 624         hook.stdout_to_stderr = 1;
 625         if (index_file) {
 626                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 627                 env[0] = index;
 628                 env[1] = NULL;
 629                 hook.env = env;
 630         }
 631
 632         ret = run_command(&hook);
 633         free(argv);
 634         return ret;
 635 }