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         char msg[4096];
  81         int len = vsnprintf(msg, sizeof(msg), err, params);
  82         if (len > sizeof(msg))
  83                 len = sizeof(msg);
  84
  85         write_in_full(child_err, "fatal: ", 7);
  86         write_in_full(child_err, msg, len);
  87         write_in_full(child_err, "\n", 1);
  88         exit(128);
  89 }
  90 #endif
  91
  92 static inline void set_cloexec(int fd)
  93 {
  94         int flags = fcntl(fd, F_GETFD);
  95         if (flags >= 0)
  96                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
  97 }
  98
  99 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 100 {
 101         int status, code = -1;
 102         pid_t waiting;
 103         int failed_errno = 0;
 104
 105         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 106                 ;       /* nothing */
 107
 108         if (waiting < 0) {
 109                 failed_errno = errno;
 110                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 111         } else if (waiting != pid) {
 112                 error("waitpid is confused (%s)", argv0);
 113         } else if (WIFSIGNALED(status)) {
 114                 code = WTERMSIG(status);
 115                 error("%s died of signal %d", argv0, code);
 116                 /*
 117                  * This return value is chosen so that code & 0xff
 118                  * mimics the exit code that a POSIX shell would report for
 119                  * a program that died from this signal.
 120                  */
 121                 code -= 128;
 122         } else if (WIFEXITED(status)) {
 123                 code = WEXITSTATUS(status);
 124                 /*
 125                  * Convert special exit code when execvp failed.
 126                  */
 127                 if (code == 127) {
 128                         code = -1;
 129                         failed_errno = ENOENT;
 130                         if (!silent_exec_failure)
 131                                 error("cannot run %s: %s", argv0,
 132                                         strerror(ENOENT));
 133                 }
 134         } else {
 135                 error("waitpid is confused (%s)", argv0);
 136         }
 137         errno = failed_errno;
 138         return code;
 139 }
 140
 141 int start_command(struct child_process *cmd)
 142 {
 143         int need_in, need_out, need_err;
 144         int fdin[2], fdout[2], fderr[2];
 145         int failed_errno = failed_errno;
 146
 147         /*
 148          * In case of errors we must keep the promise to close FDs
 149          * that have been passed in via ->in and ->out.
 150          */
 151
 152         need_in = !cmd->no_stdin && cmd->in < 0;
 153         if (need_in) {
 154                 if (pipe(fdin) < 0) {
 155                         failed_errno = errno;
 156                         if (cmd->out > 0)
 157                                 close(cmd->out);
 158                         goto fail_pipe;
 159                 }
 160                 cmd->in = fdin[1];
 161         }
 162
 163         need_out = !cmd->no_stdout
 164                 && !cmd->stdout_to_stderr
 165                 && cmd->out < 0;
 166         if (need_out) {
 167                 if (pipe(fdout) < 0) {
 168                         failed_errno = errno;
 169                         if (need_in)
 170                                 close_pair(fdin);
 171                         else if (cmd->in)
 172                                 close(cmd->in);
 173                         goto fail_pipe;
 174                 }
 175                 cmd->out = fdout[0];
 176         }
 177
 178         need_err = !cmd->no_stderr && cmd->err < 0;
 179         if (need_err) {
 180                 if (pipe(fderr) < 0) {
 181                         failed_errno = errno;
 182                         if (need_in)
 183                                 close_pair(fdin);
 184                         else if (cmd->in)
 185                                 close(cmd->in);
 186                         if (need_out)
 187                                 close_pair(fdout);
 188                         else if (cmd->out)
 189                                 close(cmd->out);
 190 fail_pipe:
 191                         error("cannot create pipe for %s: %s",
 192                                 cmd->argv[0], strerror(failed_errno));
 193                         errno = failed_errno;
 194                         return -1;
 195                 }
 196                 cmd->err = fderr[0];
 197         }
 198
 199         trace_argv_printf(cmd->argv, "trace: run_command:");
 200         fflush(NULL);
 201
 202 #ifndef WIN32
 203 {
 204         int notify_pipe[2];
 205         if (pipe(notify_pipe))
 206                 notify_pipe[0] = notify_pipe[1] = -1;
 207
 208         cmd->pid = fork();
 209         if (!cmd->pid) {
 210                 /*
 211                  * Redirect the channel to write syscall error messages to
 212                  * before redirecting the process's stderr so that all die()
 213                  * in subsequent call paths use the parent's stderr.
 214                  */
 215                 if (cmd->no_stderr || need_err) {
 216                         child_err = dup(2);
 217                         set_cloexec(child_err);
 218                 }
 219                 set_die_routine(die_child);
 220
 221                 close(notify_pipe[0]);
 222                 set_cloexec(notify_pipe[1]);
 223                 child_notifier = notify_pipe[1];
 224                 atexit(notify_parent);
 225
 226                 if (cmd->no_stdin)
 227                         dup_devnull(0);
 228                 else if (need_in) {
 229                         dup2(fdin[0], 0);
 230                         close_pair(fdin);
 231                 } else if (cmd->in) {
 232                         dup2(cmd->in, 0);
 233                         close(cmd->in);
 234                 }
 235
 236                 if (cmd->no_stderr)
 237                         dup_devnull(2);
 238                 else if (need_err) {
 239                         dup2(fderr[1], 2);
 240                         close_pair(fderr);
 241                 } else if (cmd->err > 1) {
 242                         dup2(cmd->err, 2);
 243                         close(cmd->err);
 244                 }
 245
 246                 if (cmd->no_stdout)
 247                         dup_devnull(1);
 248                 else if (cmd->stdout_to_stderr)
 249                         dup2(2, 1);
 250                 else if (need_out) {
 251                         dup2(fdout[1], 1);
 252                         close_pair(fdout);
 253                 } else if (cmd->out > 1) {
 254                         dup2(cmd->out, 1);
 255                         close(cmd->out);
 256                 }
 257
 258                 if (cmd->dir && chdir(cmd->dir))
 259                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 260                             cmd->dir);
 261                 if (cmd->env) {
 262                         for (; *cmd->env; cmd->env++) {
 263                                 if (strchr(*cmd->env, '='))
 264                                         putenv((char *)*cmd->env);
 265                                 else
 266                                         unsetenv(*cmd->env);
 267                         }
 268                 }
 269                 if (cmd->preexec_cb) {
 270                         /*
 271                          * We cannot predict what the pre-exec callback does.
 272                          * Forgo parent notification.
 273                          */
 274                         close(child_notifier);
 275                         child_notifier = -1;
 276
 277                         cmd->preexec_cb();
 278                 }
 279                 if (cmd->git_cmd) {
 280                         execv_git_cmd(cmd->argv);
 281                 } else if (cmd->use_shell) {
 282                         execv_shell_cmd(cmd->argv);
 283                 } else {
 284                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 285                 }
 286                 /*
 287                  * Do not check for cmd->silent_exec_failure; the parent
 288                  * process will check it when it sees this exit code.
 289                  */
 290                 if (errno == ENOENT)
 291                         exit(127);
 292                 else
 293                         die_errno("cannot exec '%s'", cmd->argv[0]);
 294         }
 295         if (cmd->pid < 0)
 296                 error("cannot fork() for %s: %s", cmd->argv[0],
 297                         strerror(failed_errno = errno));
 298
 299         /*
 300          * Wait for child's execvp. If the execvp succeeds (or if fork()
 301          * failed), EOF is seen immediately by the parent. Otherwise, the
 302          * child process sends a single byte.
 303          * Note that use of this infrastructure is completely advisory,
 304          * therefore, we keep error checks minimal.
 305          */
 306         close(notify_pipe[1]);
 307         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 308                 /*
 309                  * At this point we know that fork() succeeded, but execvp()
 310                  * failed. Errors have been reported to our stderr.
 311                  */
 312                 wait_or_whine(cmd->pid, cmd->argv[0],
 313                               cmd->silent_exec_failure);
 314                 failed_errno = errno;
 315                 cmd->pid = -1;
 316         }
 317         close(notify_pipe[0]);
 318 }
 319 #else
 320 {
 321         int fhin = 0, fhout = 1, fherr = 2;
 322         const char **sargv = cmd->argv;
 323         char **env = environ;
 324
 325         if (cmd->no_stdin)
 326                 fhin = open("/dev/null", O_RDWR);
 327         else if (need_in)
 328                 fhin = dup(fdin[0]);
 329         else if (cmd->in)
 330                 fhin = dup(cmd->in);
 331
 332         if (cmd->no_stderr)
 333                 fherr = open("/dev/null", O_RDWR);
 334         else if (need_err)
 335                 fherr = dup(fderr[1]);
 336         else if (cmd->err > 2)
 337                 fherr = dup(cmd->err);
 338
 339         if (cmd->no_stdout)
 340                 fhout = open("/dev/null", O_RDWR);
 341         else if (cmd->stdout_to_stderr)
 342                 fhout = dup(fherr);
 343         else if (need_out)
 344                 fhout = dup(fdout[1]);
 345         else if (cmd->out > 1)
 346                 fhout = dup(cmd->out);
 347
 348         if (cmd->env)
 349                 env = make_augmented_environ(cmd->env);
 350
 351         if (cmd->git_cmd) {
 352                 cmd->argv = prepare_git_cmd(cmd->argv);
 353         } else if (cmd->use_shell) {
 354                 cmd->argv = prepare_shell_cmd(cmd->argv);
 355         }
 356
 357         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 358                                   fhin, fhout, fherr);
 359         failed_errno = errno;
 360         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 361                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 362
 363         if (cmd->env)
 364                 free_environ(env);
 365         if (cmd->git_cmd)
 366                 free(cmd->argv);
 367
 368         cmd->argv = sargv;
 369         if (fhin != 0)
 370                 close(fhin);
 371         if (fhout != 1)
 372                 close(fhout);
 373         if (fherr != 2)
 374                 close(fherr);
 375 }
 376 #endif
 377
 378         if (cmd->pid < 0) {
 379                 if (need_in)
 380                         close_pair(fdin);
 381                 else if (cmd->in)
 382                         close(cmd->in);
 383                 if (need_out)
 384                         close_pair(fdout);
 385                 else if (cmd->out)
 386                         close(cmd->out);
 387                 if (need_err)
 388                         close_pair(fderr);
 389                 else if (cmd->err)
 390                         close(cmd->err);
 391                 errno = failed_errno;
 392                 return -1;
 393         }
 394
 395         if (need_in)
 396                 close(fdin[0]);
 397         else if (cmd->in)
 398                 close(cmd->in);
 399
 400         if (need_out)
 401                 close(fdout[1]);
 402         else if (cmd->out)
 403                 close(cmd->out);
 404
 405         if (need_err)
 406                 close(fderr[1]);
 407         else if (cmd->err)
 408                 close(cmd->err);
 409
 410         return 0;
 411 }
 412
 413 int finish_command(struct child_process *cmd)
 414 {
 415         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 416 }
 417
 418 int run_command(struct child_process *cmd)
 419 {
 420         int code = start_command(cmd);
 421         if (code)
 422                 return code;
 423         return finish_command(cmd);
 424 }
 425
 426 static void prepare_run_command_v_opt(struct child_process *cmd,
 427                                       const char **argv,
 428                                       int opt)
 429 {
 430         memset(cmd, 0, sizeof(*cmd));
 431         cmd->argv = argv;
 432         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 433         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 434         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 435         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 436         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 437 }
 438
 439 int run_command_v_opt(const char **argv, int opt)
 440 {
 441         struct child_process cmd;
 442         prepare_run_command_v_opt(&cmd, argv, opt);
 443         return run_command(&cmd);
 444 }
 445
 446 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 447 {
 448         struct child_process cmd;
 449         prepare_run_command_v_opt(&cmd, argv, opt);
 450         cmd.dir = dir;
 451         cmd.env = env;
 452         return run_command(&cmd);
 453 }
 454
 455 #ifndef NO_PTHREADS
 456 static pthread_t main_thread;
 457 static int main_thread_set;
 458 static pthread_key_t async_key;
 459
 460 static void *run_thread(void *data)
 461 {
 462         struct async *async = data;
 463         intptr_t ret;
 464
 465         pthread_setspecific(async_key, async);
 466         ret = async->proc(async->proc_in, async->proc_out, async->data);
 467         return (void *)ret;
 468 }
 469
 470 static NORETURN void die_async(const char *err, va_list params)
 471 {
 472         vreportf("fatal: ", err, params);
 473
 474         if (!pthread_equal(main_thread, pthread_self())) {
 475                 struct async *async = pthread_getspecific(async_key);
 476                 if (async->proc_in >= 0)
 477                         close(async->proc_in);
 478                 if (async->proc_out >= 0)
 479                         close(async->proc_out);
 480                 pthread_exit((void *)128);
 481         }
 482
 483         exit(128);
 484 }
 485 #endif
 486
 487 int start_async(struct async *async)
 488 {
 489         int need_in, need_out;
 490         int fdin[2], fdout[2];
 491         int proc_in, proc_out;
 492
 493         need_in = async->in < 0;
 494         if (need_in) {
 495                 if (pipe(fdin) < 0) {
 496                         if (async->out > 0)
 497                                 close(async->out);
 498                         return error("cannot create pipe: %s", strerror(errno));
 499                 }
 500                 async->in = fdin[1];
 501         }
 502
 503         need_out = async->out < 0;
 504         if (need_out) {
 505                 if (pipe(fdout) < 0) {
 506                         if (need_in)
 507                                 close_pair(fdin);
 508                         else if (async->in)
 509                                 close(async->in);
 510                         return error("cannot create pipe: %s", strerror(errno));
 511                 }
 512                 async->out = fdout[0];
 513         }
 514
 515         if (need_in)
 516                 proc_in = fdin[0];
 517         else if (async->in)
 518                 proc_in = async->in;
 519         else
 520                 proc_in = -1;
 521
 522         if (need_out)
 523                 proc_out = fdout[1];
 524         else if (async->out)
 525                 proc_out = async->out;
 526         else
 527                 proc_out = -1;
 528
 529 #ifdef NO_PTHREADS
 530         /* Flush stdio before fork() to avoid cloning buffers */
 531         fflush(NULL);
 532
 533         async->pid = fork();
 534         if (async->pid < 0) {
 535                 error("fork (async) failed: %s", strerror(errno));
 536                 goto error;
 537         }
 538         if (!async->pid) {
 539                 if (need_in)
 540                         close(fdin[1]);
 541                 if (need_out)
 542                         close(fdout[0]);
 543                 exit(!!async->proc(proc_in, proc_out, async->data));
 544         }
 545
 546         if (need_in)
 547                 close(fdin[0]);
 548         else if (async->in)
 549                 close(async->in);
 550
 551         if (need_out)
 552                 close(fdout[1]);
 553         else if (async->out)
 554                 close(async->out);
 555 #else
 556         if (!main_thread_set) {
 557                 /*
 558                  * We assume that the first time that start_async is called
 559                  * it is from the main thread.
 560                  */
 561                 main_thread_set = 1;
 562                 main_thread = pthread_self();
 563                 pthread_key_create(&async_key, NULL);
 564                 set_die_routine(die_async);
 565         }
 566
 567         if (proc_in >= 0)
 568                 set_cloexec(proc_in);
 569         if (proc_out >= 0)
 570                 set_cloexec(proc_out);
 571         async->proc_in = proc_in;
 572         async->proc_out = proc_out;
 573         {
 574                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 575                 if (err) {
 576                         error("cannot create thread: %s", strerror(err));
 577                         goto error;
 578                 }
 579         }
 580 #endif
 581         return 0;
 582
 583 error:
 584         if (need_in)
 585                 close_pair(fdin);
 586         else if (async->in)
 587                 close(async->in);
 588
 589         if (need_out)
 590                 close_pair(fdout);
 591         else if (async->out)
 592                 close(async->out);
 593         return -1;
 594 }
 595
 596 int finish_async(struct async *async)
 597 {
 598 #ifdef NO_PTHREADS
 599         return wait_or_whine(async->pid, "child process", 0);
 600 #else
 601         void *ret = (void *)(intptr_t)(-1);
 602
 603         if (pthread_join(async->tid, &ret))
 604                 error("pthread_join failed");
 605         return (int)(intptr_t)ret;
 606 #endif
 607 }
 608
 609 int run_hook(const char *index_file, const char *name, ...)
 610 {
 611         struct child_process hook;
 612         const char **argv = NULL, *env[2];
 613         char index[PATH_MAX];
 614         va_list args;
 615         int ret;
 616         size_t i = 0, alloc = 0;
 617
 618         if (access(git_path("hooks/%s", name), X_OK) < 0)
 619                 return 0;
 620
 621         va_start(args, name);
 622         ALLOC_GROW(argv, i + 1, alloc);
 623         argv[i++] = git_path("hooks/%s", name);
 624         while (argv[i-1]) {
 625                 ALLOC_GROW(argv, i + 1, alloc);
 626                 argv[i++] = va_arg(args, const char *);
 627         }
 628         va_end(args);
 629
 630         memset(&hook, 0, sizeof(hook));
 631         hook.argv = argv;
 632         hook.no_stdin = 1;
 633         hook.stdout_to_stderr = 1;
 634         if (index_file) {
 635                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 636                 env[0] = index;
 637                 env[1] = NULL;
 638                 hook.env = env;
 639         }
 640
 641         ret = run_command(&hook);
 642         free(argv);
 643         return ret;
 644 }