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         char **env = environ;
 321
 322         if (cmd->no_stdin)
 323                 fhin = open("/dev/null", O_RDWR);
 324         else if (need_in)
 325                 fhin = dup(fdin[0]);
 326         else if (cmd->in)
 327                 fhin = dup(cmd->in);
 328
 329         if (cmd->no_stderr)
 330                 fherr = open("/dev/null", O_RDWR);
 331         else if (need_err)
 332                 fherr = dup(fderr[1]);
 333         else if (cmd->err > 2)
 334                 fherr = dup(cmd->err);
 335
 336         if (cmd->no_stdout)
 337                 fhout = open("/dev/null", O_RDWR);
 338         else if (cmd->stdout_to_stderr)
 339                 fhout = dup(fherr);
 340         else if (need_out)
 341                 fhout = dup(fdout[1]);
 342         else if (cmd->out > 1)
 343                 fhout = dup(cmd->out);
 344
 345         if (cmd->env)
 346                 env = make_augmented_environ(cmd->env);
 347
 348         if (cmd->git_cmd) {
 349                 cmd->argv = prepare_git_cmd(cmd->argv);
 350         } else if (cmd->use_shell) {
 351                 cmd->argv = prepare_shell_cmd(cmd->argv);
 352         }
 353
 354         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 355                                   fhin, fhout, fherr);
 356         failed_errno = errno;
 357         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 358                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 359
 360         if (cmd->env)
 361                 free_environ(env);
 362         if (cmd->git_cmd)
 363                 free(cmd->argv);
 364
 365         cmd->argv = sargv;
 366         if (fhin != 0)
 367                 close(fhin);
 368         if (fhout != 1)
 369                 close(fhout);
 370         if (fherr != 2)
 371                 close(fherr);
 372 }
 373 #endif
 374
 375         if (cmd->pid < 0) {
 376                 if (need_in)
 377                         close_pair(fdin);
 378                 else if (cmd->in)
 379                         close(cmd->in);
 380                 if (need_out)
 381                         close_pair(fdout);
 382                 else if (cmd->out)
 383                         close(cmd->out);
 384                 if (need_err)
 385                         close_pair(fderr);
 386                 else if (cmd->err)
 387                         close(cmd->err);
 388                 errno = failed_errno;
 389                 return -1;
 390         }
 391
 392         if (need_in)
 393                 close(fdin[0]);
 394         else if (cmd->in)
 395                 close(cmd->in);
 396
 397         if (need_out)
 398                 close(fdout[1]);
 399         else if (cmd->out)
 400                 close(cmd->out);
 401
 402         if (need_err)
 403                 close(fderr[1]);
 404         else if (cmd->err)
 405                 close(cmd->err);
 406
 407         return 0;
 408 }
 409
 410 int finish_command(struct child_process *cmd)
 411 {
 412         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 413 }
 414
 415 int run_command(struct child_process *cmd)
 416 {
 417         int code = start_command(cmd);
 418         if (code)
 419                 return code;
 420         return finish_command(cmd);
 421 }
 422
 423 static void prepare_run_command_v_opt(struct child_process *cmd,
 424                                       const char **argv,
 425                                       int opt)
 426 {
 427         memset(cmd, 0, sizeof(*cmd));
 428         cmd->argv = argv;
 429         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 430         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 431         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 432         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 433         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 434 }
 435
 436 int run_command_v_opt(const char **argv, int opt)
 437 {
 438         struct child_process cmd;
 439         prepare_run_command_v_opt(&cmd, argv, opt);
 440         return run_command(&cmd);
 441 }
 442
 443 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 444 {
 445         struct child_process cmd;
 446         prepare_run_command_v_opt(&cmd, argv, opt);
 447         cmd.dir = dir;
 448         cmd.env = env;
 449         return run_command(&cmd);
 450 }
 451
 452 #ifndef NO_PTHREADS
 453 static pthread_t main_thread;
 454 static int main_thread_set;
 455 static pthread_key_t async_key;
 456
 457 static void *run_thread(void *data)
 458 {
 459         struct async *async = data;
 460         intptr_t ret;
 461
 462         pthread_setspecific(async_key, async);
 463         ret = async->proc(async->proc_in, async->proc_out, async->data);
 464         return (void *)ret;
 465 }
 466
 467 static NORETURN void die_async(const char *err, va_list params)
 468 {
 469         vreportf("fatal: ", err, params);
 470
 471         if (!pthread_equal(main_thread, pthread_self())) {
 472                 struct async *async = pthread_getspecific(async_key);
 473                 if (async->proc_in >= 0)
 474                         close(async->proc_in);
 475                 if (async->proc_out >= 0)
 476                         close(async->proc_out);
 477                 pthread_exit((void *)128);
 478         }
 479
 480         exit(128);
 481 }
 482 #endif
 483
 484 int start_async(struct async *async)
 485 {
 486         int need_in, need_out;
 487         int fdin[2], fdout[2];
 488         int proc_in, proc_out;
 489
 490         need_in = async->in < 0;
 491         if (need_in) {
 492                 if (pipe(fdin) < 0) {
 493                         if (async->out > 0)
 494                                 close(async->out);
 495                         return error("cannot create pipe: %s", strerror(errno));
 496                 }
 497                 async->in = fdin[1];
 498         }
 499
 500         need_out = async->out < 0;
 501         if (need_out) {
 502                 if (pipe(fdout) < 0) {
 503                         if (need_in)
 504                                 close_pair(fdin);
 505                         else if (async->in)
 506                                 close(async->in);
 507                         return error("cannot create pipe: %s", strerror(errno));
 508                 }
 509                 async->out = fdout[0];
 510         }
 511
 512         if (need_in)
 513                 proc_in = fdin[0];
 514         else if (async->in)
 515                 proc_in = async->in;
 516         else
 517                 proc_in = -1;
 518
 519         if (need_out)
 520                 proc_out = fdout[1];
 521         else if (async->out)
 522                 proc_out = async->out;
 523         else
 524                 proc_out = -1;
 525
 526 #ifdef NO_PTHREADS
 527         /* Flush stdio before fork() to avoid cloning buffers */
 528         fflush(NULL);
 529
 530         async->pid = fork();
 531         if (async->pid < 0) {
 532                 error("fork (async) failed: %s", strerror(errno));
 533                 goto error;
 534         }
 535         if (!async->pid) {
 536                 if (need_in)
 537                         close(fdin[1]);
 538                 if (need_out)
 539                         close(fdout[0]);
 540                 exit(!!async->proc(proc_in, proc_out, async->data));
 541         }
 542
 543         if (need_in)
 544                 close(fdin[0]);
 545         else if (async->in)
 546                 close(async->in);
 547
 548         if (need_out)
 549                 close(fdout[1]);
 550         else if (async->out)
 551                 close(async->out);
 552 #else
 553         if (!main_thread_set) {
 554                 /*
 555                  * We assume that the first time that start_async is called
 556                  * it is from the main thread.
 557                  */
 558                 main_thread_set = 1;
 559                 main_thread = pthread_self();
 560                 pthread_key_create(&async_key, NULL);
 561                 set_die_routine(die_async);
 562         }
 563
 564         if (proc_in >= 0)
 565                 set_cloexec(proc_in);
 566         if (proc_out >= 0)
 567                 set_cloexec(proc_out);
 568         async->proc_in = proc_in;
 569         async->proc_out = proc_out;
 570         {
 571                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 572                 if (err) {
 573                         error("cannot create thread: %s", strerror(err));
 574                         goto error;
 575                 }
 576         }
 577 #endif
 578         return 0;
 579
 580 error:
 581         if (need_in)
 582                 close_pair(fdin);
 583         else if (async->in)
 584                 close(async->in);
 585
 586         if (need_out)
 587                 close_pair(fdout);
 588         else if (async->out)
 589                 close(async->out);
 590         return -1;
 591 }
 592
 593 int finish_async(struct async *async)
 594 {
 595 #ifdef NO_PTHREADS
 596         return wait_or_whine(async->pid, "child process", 0);
 597 #else
 598         void *ret = (void *)(intptr_t)(-1);
 599
 600         if (pthread_join(async->tid, &ret))
 601                 error("pthread_join failed");
 602         return (int)(intptr_t)ret;
 603 #endif
 604 }
 605
 606 int run_hook(const char *index_file, const char *name, ...)
 607 {
 608         struct child_process hook;
 609         const char **argv = NULL, *env[2];
 610         char index[PATH_MAX];
 611         va_list args;
 612         int ret;
 613         size_t i = 0, alloc = 0;
 614
 615         if (access(git_path("hooks/%s", name), X_OK) < 0)
 616                 return 0;
 617
 618         va_start(args, name);
 619         ALLOC_GROW(argv, i + 1, alloc);
 620         argv[i++] = git_path("hooks/%s", name);
 621         while (argv[i-1]) {
 622                 ALLOC_GROW(argv, i + 1, alloc);
 623                 argv[i++] = va_arg(args, const char *);
 624         }
 625         va_end(args);
 626
 627         memset(&hook, 0, sizeof(hook));
 628         hook.argv = argv;
 629         hook.no_stdin = 1;
 630         hook.stdout_to_stderr = 1;
 631         if (index_file) {
 632                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 633                 env[0] = index;
 634                 env[1] = NULL;
 635                 hook.env = env;
 636         }
 637
 638         ret = run_command(&hook);
 639         free(argv);
 640         return ret;
 641 }