run-command.c

   1 #include "cache.h"
   2 #include "run-command.h"
   3 #include "exec_cmd.h"
   4 #include "argv-array.h"
   5
   6 static inline void close_pair(int fd[2])
   7 {
   8         close(fd[0]);
   9         close(fd[1]);
  10 }
  11
  12 #ifndef WIN32
  13 static inline void dup_devnull(int to)
  14 {
  15         int fd = open("/dev/null", O_RDWR);
  16         dup2(fd, to);
  17         close(fd);
  18 }
  19 #endif
  20
  21 static const char **prepare_shell_cmd(const char **argv)
  22 {
  23         int argc, nargc = 0;
  24         const char **nargv;
  25
  26         for (argc = 0; argv[argc]; argc++)
  27                 ; /* just counting */
  28         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
  29         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
  30
  31         if (argc < 1)
  32                 die("BUG: shell command is empty");
  33
  34         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
  35                 nargv[nargc++] = "sh";
  36                 nargv[nargc++] = "-c";
  37
  38                 if (argc < 2)
  39                         nargv[nargc++] = argv[0];
  40                 else {
  41                         struct strbuf arg0 = STRBUF_INIT;
  42                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
  43                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
  44                 }
  45         }
  46
  47         for (argc = 0; argv[argc]; argc++)
  48                 nargv[nargc++] = argv[argc];
  49         nargv[nargc] = NULL;
  50
  51         return nargv;
  52 }
  53
  54 #ifndef WIN32
  55 static int execv_shell_cmd(const char **argv)
  56 {
  57         const char **nargv = prepare_shell_cmd(argv);
  58         trace_argv_printf(nargv, "trace: exec:");
  59         execvp(nargv[0], (char **)nargv);
  60         free(nargv);
  61         return -1;
  62 }
  63 #endif
  64
  65 #ifndef WIN32
  66 static int child_err = 2;
  67 static int child_notifier = -1;
  68
  69 static void notify_parent(void)
  70 {
  71         /*
  72          * execvp failed.  If possible, we'd like to let start_command
  73          * know, so failures like ENOENT can be handled right away; but
  74          * otherwise, finish_command will still report the error.
  75          */
  76         xwrite(child_notifier, "", 1);
  77 }
  78
  79 static NORETURN void die_child(const char *err, va_list params)
  80 {
  81         char msg[4096];
  82         int len = vsnprintf(msg, sizeof(msg), err, params);
  83         if (len > sizeof(msg))
  84                 len = sizeof(msg);
  85
  86         write_in_full(child_err, "fatal: ", 7);
  87         write_in_full(child_err, msg, len);
  88         write_in_full(child_err, "\n", 1);
  89         exit(128);
  90 }
  91 #endif
  92
  93 static inline void set_cloexec(int fd)
  94 {
  95         int flags = fcntl(fd, F_GETFD);
  96         if (flags >= 0)
  97                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
  98 }
  99
 100 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 101 {
 102         int status, code = -1;
 103         pid_t waiting;
 104         int failed_errno = 0;
 105
 106         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 107                 ;       /* nothing */
 108
 109         if (waiting < 0) {
 110                 failed_errno = errno;
 111                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 112         } else if (waiting != pid) {
 113                 error("waitpid is confused (%s)", argv0);
 114         } else if (WIFSIGNALED(status)) {
 115                 code = WTERMSIG(status);
 116                 error("%s died of signal %d", argv0, code);
 117                 /*
 118                  * This return value is chosen so that code & 0xff
 119                  * mimics the exit code that a POSIX shell would report for
 120                  * a program that died from this signal.
 121                  */
 122                 code -= 128;
 123         } else if (WIFEXITED(status)) {
 124                 code = WEXITSTATUS(status);
 125                 /*
 126                  * Convert special exit code when execvp failed.
 127                  */
 128                 if (code == 127) {
 129                         code = -1;
 130                         failed_errno = ENOENT;
 131                         if (!silent_exec_failure)
 132                                 error("cannot run %s: %s", argv0,
 133                                         strerror(ENOENT));
 134                 }
 135         } else {
 136                 error("waitpid is confused (%s)", argv0);
 137         }
 138         errno = failed_errno;
 139         return code;
 140 }
 141
 142 int start_command(struct child_process *cmd)
 143 {
 144         int need_in, need_out, need_err;
 145         int fdin[2], fdout[2], fderr[2];
 146         int failed_errno = failed_errno;
 147
 148         /*
 149          * In case of errors we must keep the promise to close FDs
 150          * that have been passed in via ->in and ->out.
 151          */
 152
 153         need_in = !cmd->no_stdin && cmd->in < 0;
 154         if (need_in) {
 155                 if (pipe(fdin) < 0) {
 156                         failed_errno = errno;
 157                         if (cmd->out > 0)
 158                                 close(cmd->out);
 159                         goto fail_pipe;
 160                 }
 161                 cmd->in = fdin[1];
 162         }
 163
 164         need_out = !cmd->no_stdout
 165                 && !cmd->stdout_to_stderr
 166                 && cmd->out < 0;
 167         if (need_out) {
 168                 if (pipe(fdout) < 0) {
 169                         failed_errno = errno;
 170                         if (need_in)
 171                                 close_pair(fdin);
 172                         else if (cmd->in)
 173                                 close(cmd->in);
 174                         goto fail_pipe;
 175                 }
 176                 cmd->out = fdout[0];
 177         }
 178
 179         need_err = !cmd->no_stderr && cmd->err < 0;
 180         if (need_err) {
 181                 if (pipe(fderr) < 0) {
 182                         failed_errno = errno;
 183                         if (need_in)
 184                                 close_pair(fdin);
 185                         else if (cmd->in)
 186                                 close(cmd->in);
 187                         if (need_out)
 188                                 close_pair(fdout);
 189                         else if (cmd->out)
 190                                 close(cmd->out);
 191 fail_pipe:
 192                         error("cannot create pipe for %s: %s",
 193                                 cmd->argv[0], strerror(failed_errno));
 194                         errno = failed_errno;
 195                         return -1;
 196                 }
 197                 cmd->err = fderr[0];
 198         }
 199
 200         trace_argv_printf(cmd->argv, "trace: run_command:");
 201         fflush(NULL);
 202
 203 #ifndef WIN32
 204 {
 205         int notify_pipe[2];
 206         if (pipe(notify_pipe))
 207                 notify_pipe[0] = notify_pipe[1] = -1;
 208
 209         cmd->pid = fork();
 210         if (!cmd->pid) {
 211                 /*
 212                  * Redirect the channel to write syscall error messages to
 213                  * before redirecting the process's stderr so that all die()
 214                  * in subsequent call paths use the parent's stderr.
 215                  */
 216                 if (cmd->no_stderr || need_err) {
 217                         child_err = dup(2);
 218                         set_cloexec(child_err);
 219                 }
 220                 set_die_routine(die_child);
 221
 222                 close(notify_pipe[0]);
 223                 set_cloexec(notify_pipe[1]);
 224                 child_notifier = notify_pipe[1];
 225                 atexit(notify_parent);
 226
 227                 if (cmd->no_stdin)
 228                         dup_devnull(0);
 229                 else if (need_in) {
 230                         dup2(fdin[0], 0);
 231                         close_pair(fdin);
 232                 } else if (cmd->in) {
 233                         dup2(cmd->in, 0);
 234                         close(cmd->in);
 235                 }
 236
 237                 if (cmd->no_stderr)
 238                         dup_devnull(2);
 239                 else if (need_err) {
 240                         dup2(fderr[1], 2);
 241                         close_pair(fderr);
 242                 } else if (cmd->err > 1) {
 243                         dup2(cmd->err, 2);
 244                         close(cmd->err);
 245                 }
 246
 247                 if (cmd->no_stdout)
 248                         dup_devnull(1);
 249                 else if (cmd->stdout_to_stderr)
 250                         dup2(2, 1);
 251                 else if (need_out) {
 252                         dup2(fdout[1], 1);
 253                         close_pair(fdout);
 254                 } else if (cmd->out > 1) {
 255                         dup2(cmd->out, 1);
 256                         close(cmd->out);
 257                 }
 258
 259                 if (cmd->dir && chdir(cmd->dir))
 260                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 261                             cmd->dir);
 262                 if (cmd->env) {
 263                         for (; *cmd->env; cmd->env++) {
 264                                 if (strchr(*cmd->env, '='))
 265                                         putenv((char *)*cmd->env);
 266                                 else
 267                                         unsetenv(*cmd->env);
 268                         }
 269                 }
 270                 if (cmd->preexec_cb) {
 271                         /*
 272                          * We cannot predict what the pre-exec callback does.
 273                          * Forgo parent notification.
 274                          */
 275                         close(child_notifier);
 276                         child_notifier = -1;
 277
 278                         cmd->preexec_cb();
 279                 }
 280                 if (cmd->git_cmd) {
 281                         execv_git_cmd(cmd->argv);
 282                 } else if (cmd->use_shell) {
 283                         execv_shell_cmd(cmd->argv);
 284                 } else {
 285                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 286                 }
 287                 /*
 288                  * Do not check for cmd->silent_exec_failure; the parent
 289                  * process will check it when it sees this exit code.
 290                  */
 291                 if (errno == ENOENT)
 292                         exit(127);
 293                 else
 294                         die_errno("cannot exec '%s'", cmd->argv[0]);
 295         }
 296         if (cmd->pid < 0)
 297                 error("cannot fork() for %s: %s", cmd->argv[0],
 298                         strerror(failed_errno = errno));
 299
 300         /*
 301          * Wait for child's execvp. If the execvp succeeds (or if fork()
 302          * failed), EOF is seen immediately by the parent. Otherwise, the
 303          * child process sends a single byte.
 304          * Note that use of this infrastructure is completely advisory,
 305          * therefore, we keep error checks minimal.
 306          */
 307         close(notify_pipe[1]);
 308         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 309                 /*
 310                  * At this point we know that fork() succeeded, but execvp()
 311                  * failed. Errors have been reported to our stderr.
 312                  */
 313                 wait_or_whine(cmd->pid, cmd->argv[0],
 314                               cmd->silent_exec_failure);
 315                 failed_errno = errno;
 316                 cmd->pid = -1;
 317         }
 318         close(notify_pipe[0]);
 319 }
 320 #else
 321 {
 322         int fhin = 0, fhout = 1, fherr = 2;
 323         const char **sargv = cmd->argv;
 324         char **env = environ;
 325
 326         if (cmd->no_stdin)
 327                 fhin = open("/dev/null", O_RDWR);
 328         else if (need_in)
 329                 fhin = dup(fdin[0]);
 330         else if (cmd->in)
 331                 fhin = dup(cmd->in);
 332
 333         if (cmd->no_stderr)
 334                 fherr = open("/dev/null", O_RDWR);
 335         else if (need_err)
 336                 fherr = dup(fderr[1]);
 337         else if (cmd->err > 2)
 338                 fherr = dup(cmd->err);
 339
 340         if (cmd->no_stdout)
 341                 fhout = open("/dev/null", O_RDWR);
 342         else if (cmd->stdout_to_stderr)
 343                 fhout = dup(fherr);
 344         else if (need_out)
 345                 fhout = dup(fdout[1]);
 346         else if (cmd->out > 1)
 347                 fhout = dup(cmd->out);
 348
 349         if (cmd->env)
 350                 env = make_augmented_environ(cmd->env);
 351
 352         if (cmd->git_cmd) {
 353                 cmd->argv = prepare_git_cmd(cmd->argv);
 354         } else if (cmd->use_shell) {
 355                 cmd->argv = prepare_shell_cmd(cmd->argv);
 356         }
 357
 358         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 359                                   fhin, fhout, fherr);
 360         failed_errno = errno;
 361         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 362                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 363
 364         if (cmd->env)
 365                 free_environ(env);
 366         if (cmd->git_cmd)
 367                 free(cmd->argv);
 368
 369         cmd->argv = sargv;
 370         if (fhin != 0)
 371                 close(fhin);
 372         if (fhout != 1)
 373                 close(fhout);
 374         if (fherr != 2)
 375                 close(fherr);
 376 }
 377 #endif
 378
 379         if (cmd->pid < 0) {
 380                 if (need_in)
 381                         close_pair(fdin);
 382                 else if (cmd->in)
 383                         close(cmd->in);
 384                 if (need_out)
 385                         close_pair(fdout);
 386                 else if (cmd->out)
 387                         close(cmd->out);
 388                 if (need_err)
 389                         close_pair(fderr);
 390                 else if (cmd->err)
 391                         close(cmd->err);
 392                 errno = failed_errno;
 393                 return -1;
 394         }
 395
 396         if (need_in)
 397                 close(fdin[0]);
 398         else if (cmd->in)
 399                 close(cmd->in);
 400
 401         if (need_out)
 402                 close(fdout[1]);
 403         else if (cmd->out)
 404                 close(cmd->out);
 405
 406         if (need_err)
 407                 close(fderr[1]);
 408         else if (cmd->err)
 409                 close(cmd->err);
 410
 411         return 0;
 412 }
 413
 414 int finish_command(struct child_process *cmd)
 415 {
 416         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 417 }
 418
 419 int run_command(struct child_process *cmd)
 420 {
 421         int code = start_command(cmd);
 422         if (code)
 423                 return code;
 424         return finish_command(cmd);
 425 }
 426
 427 static void prepare_run_command_v_opt(struct child_process *cmd,
 428                                       const char **argv,
 429                                       int opt)
 430 {
 431         memset(cmd, 0, sizeof(*cmd));
 432         cmd->argv = argv;
 433         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 434         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 435         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 436         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 437         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 438 }
 439
 440 int run_command_v_opt(const char **argv, int opt)
 441 {
 442         struct child_process cmd;
 443         prepare_run_command_v_opt(&cmd, argv, opt);
 444         return run_command(&cmd);
 445 }
 446
 447 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 448 {
 449         struct child_process cmd;
 450         prepare_run_command_v_opt(&cmd, argv, opt);
 451         cmd.dir = dir;
 452         cmd.env = env;
 453         return run_command(&cmd);
 454 }
 455
 456 #ifndef NO_PTHREADS
 457 static pthread_t main_thread;
 458 static int main_thread_set;
 459 static pthread_key_t async_key;
 460
 461 static void *run_thread(void *data)
 462 {
 463         struct async *async = data;
 464         intptr_t ret;
 465
 466         pthread_setspecific(async_key, async);
 467         ret = async->proc(async->proc_in, async->proc_out, async->data);
 468         return (void *)ret;
 469 }
 470
 471 static NORETURN void die_async(const char *err, va_list params)
 472 {
 473         vreportf("fatal: ", err, params);
 474
 475         if (!pthread_equal(main_thread, pthread_self())) {
 476                 struct async *async = pthread_getspecific(async_key);
 477                 if (async->proc_in >= 0)
 478                         close(async->proc_in);
 479                 if (async->proc_out >= 0)
 480                         close(async->proc_out);
 481                 pthread_exit((void *)128);
 482         }
 483
 484         exit(128);
 485 }
 486 #endif
 487
 488 int start_async(struct async *async)
 489 {
 490         int need_in, need_out;
 491         int fdin[2], fdout[2];
 492         int proc_in, proc_out;
 493
 494         need_in = async->in < 0;
 495         if (need_in) {
 496                 if (pipe(fdin) < 0) {
 497                         if (async->out > 0)
 498                                 close(async->out);
 499                         return error("cannot create pipe: %s", strerror(errno));
 500                 }
 501                 async->in = fdin[1];
 502         }
 503
 504         need_out = async->out < 0;
 505         if (need_out) {
 506                 if (pipe(fdout) < 0) {
 507                         if (need_in)
 508                                 close_pair(fdin);
 509                         else if (async->in)
 510                                 close(async->in);
 511                         return error("cannot create pipe: %s", strerror(errno));
 512                 }
 513                 async->out = fdout[0];
 514         }
 515
 516         if (need_in)
 517                 proc_in = fdin[0];
 518         else if (async->in)
 519                 proc_in = async->in;
 520         else
 521                 proc_in = -1;
 522
 523         if (need_out)
 524                 proc_out = fdout[1];
 525         else if (async->out)
 526                 proc_out = async->out;
 527         else
 528                 proc_out = -1;
 529
 530 #ifdef NO_PTHREADS
 531         /* Flush stdio before fork() to avoid cloning buffers */
 532         fflush(NULL);
 533
 534         async->pid = fork();
 535         if (async->pid < 0) {
 536                 error("fork (async) failed: %s", strerror(errno));
 537                 goto error;
 538         }
 539         if (!async->pid) {
 540                 if (need_in)
 541                         close(fdin[1]);
 542                 if (need_out)
 543                         close(fdout[0]);
 544                 exit(!!async->proc(proc_in, proc_out, async->data));
 545         }
 546
 547         if (need_in)
 548                 close(fdin[0]);
 549         else if (async->in)
 550                 close(async->in);
 551
 552         if (need_out)
 553                 close(fdout[1]);
 554         else if (async->out)
 555                 close(async->out);
 556 #else
 557         if (!main_thread_set) {
 558                 /*
 559                  * We assume that the first time that start_async is called
 560                  * it is from the main thread.
 561                  */
 562                 main_thread_set = 1;
 563                 main_thread = pthread_self();
 564                 pthread_key_create(&async_key, NULL);
 565                 set_die_routine(die_async);
 566         }
 567
 568         if (proc_in >= 0)
 569                 set_cloexec(proc_in);
 570         if (proc_out >= 0)
 571                 set_cloexec(proc_out);
 572         async->proc_in = proc_in;
 573         async->proc_out = proc_out;
 574         {
 575                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 576                 if (err) {
 577                         error("cannot create thread: %s", strerror(err));
 578                         goto error;
 579                 }
 580         }
 581 #endif
 582         return 0;
 583
 584 error:
 585         if (need_in)
 586                 close_pair(fdin);
 587         else if (async->in)
 588                 close(async->in);
 589
 590         if (need_out)
 591                 close_pair(fdout);
 592         else if (async->out)
 593                 close(async->out);
 594         return -1;
 595 }
 596
 597 int finish_async(struct async *async)
 598 {
 599 #ifdef NO_PTHREADS
 600         return wait_or_whine(async->pid, "child process", 0);
 601 #else
 602         void *ret = (void *)(intptr_t)(-1);
 603
 604         if (pthread_join(async->tid, &ret))
 605                 error("pthread_join failed");
 606         return (int)(intptr_t)ret;
 607 #endif
 608 }
 609
 610 int run_hook(const char *index_file, const char *name, ...)
 611 {
 612         struct child_process hook;
 613         struct argv_array argv = ARGV_ARRAY_INIT;
 614         const char *p, *env[2];
 615         char index[PATH_MAX];
 616         va_list args;
 617         int ret;
 618
 619         if (access(git_path("hooks/%s", name), X_OK) < 0)
 620                 return 0;
 621
 622         va_start(args, name);
 623         argv_array_push(&argv, git_path("hooks/%s", name));
 624         while ((p = va_arg(args, const char *)))
 625                 argv_array_push(&argv, p);
 626         va_end(args);
 627
 628         memset(&hook, 0, sizeof(hook));
 629         hook.argv = argv.argv;
 630         hook.no_stdin = 1;
 631         hook.stdout_to_stderr = 1;
 632         if (index_file) {
 633                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 634                 env[0] = index;
 635                 env[1] = NULL;
 636                 hook.env = env;
 637         }
 638
 639         ret = run_command(&hook);
 640         argv_array_clear(&argv);
 641         return ret;
 642 }