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         if (write(child_notifier, "", 1))
  76                 ; /* yes, dear gcc -D_FORTIFY_SOURCE, there was an error. */
  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         if (write(child_err, "fatal: ", 7) ||
  87             write(child_err, msg, len) ||
  88             write(child_err, "\n", 1))
  89                 ; /* yes, gcc -D_FORTIFY_SOURCE, we know there was an error. */
  90         exit(128);
  91 }
  92 #endif
  93
  94 static inline void set_cloexec(int fd)
  95 {
  96         int flags = fcntl(fd, F_GETFD);
  97         if (flags >= 0)
  98                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
  99 }
 100
 101 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 102 {
 103         int status, code = -1;
 104         pid_t waiting;
 105         int failed_errno = 0;
 106
 107         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 108                 ;       /* nothing */
 109
 110         if (waiting < 0) {
 111                 failed_errno = errno;
 112                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 113         } else if (waiting != pid) {
 114                 error("waitpid is confused (%s)", argv0);
 115         } else if (WIFSIGNALED(status)) {
 116                 code = WTERMSIG(status);
 117                 error("%s died of signal %d", argv0, code);
 118                 /*
 119                  * This return value is chosen so that code & 0xff
 120                  * mimics the exit code that a POSIX shell would report for
 121                  * a program that died from this signal.
 122                  */
 123                 code -= 128;
 124         } else if (WIFEXITED(status)) {
 125                 code = WEXITSTATUS(status);
 126                 /*
 127                  * Convert special exit code when execvp failed.
 128                  */
 129                 if (code == 127) {
 130                         code = -1;
 131                         failed_errno = ENOENT;
 132                         if (!silent_exec_failure)
 133                                 error("cannot run %s: %s", argv0,
 134                                         strerror(ENOENT));
 135                 }
 136         } else {
 137                 error("waitpid is confused (%s)", argv0);
 138         }
 139         errno = failed_errno;
 140         return code;
 141 }
 142
 143 int start_command(struct child_process *cmd)
 144 {
 145         int need_in, need_out, need_err;
 146         int fdin[2], fdout[2], fderr[2];
 147         int failed_errno = failed_errno;
 148
 149         /*
 150          * In case of errors we must keep the promise to close FDs
 151          * that have been passed in via ->in and ->out.
 152          */
 153
 154         need_in = !cmd->no_stdin && cmd->in < 0;
 155         if (need_in) {
 156                 if (pipe(fdin) < 0) {
 157                         failed_errno = errno;
 158                         if (cmd->out > 0)
 159                                 close(cmd->out);
 160                         goto fail_pipe;
 161                 }
 162                 cmd->in = fdin[1];
 163         }
 164
 165         need_out = !cmd->no_stdout
 166                 && !cmd->stdout_to_stderr
 167                 && cmd->out < 0;
 168         if (need_out) {
 169                 if (pipe(fdout) < 0) {
 170                         failed_errno = errno;
 171                         if (need_in)
 172                                 close_pair(fdin);
 173                         else if (cmd->in)
 174                                 close(cmd->in);
 175                         goto fail_pipe;
 176                 }
 177                 cmd->out = fdout[0];
 178         }
 179
 180         need_err = !cmd->no_stderr && cmd->err < 0;
 181         if (need_err) {
 182                 if (pipe(fderr) < 0) {
 183                         failed_errno = errno;
 184                         if (need_in)
 185                                 close_pair(fdin);
 186                         else if (cmd->in)
 187                                 close(cmd->in);
 188                         if (need_out)
 189                                 close_pair(fdout);
 190                         else if (cmd->out)
 191                                 close(cmd->out);
 192 fail_pipe:
 193                         error("cannot create pipe for %s: %s",
 194                                 cmd->argv[0], strerror(failed_errno));
 195                         errno = failed_errno;
 196                         return -1;
 197                 }
 198                 cmd->err = fderr[0];
 199         }
 200
 201         trace_argv_printf(cmd->argv, "trace: run_command:");
 202         fflush(NULL);
 203
 204 #ifndef WIN32
 205 {
 206         int notify_pipe[2];
 207         if (pipe(notify_pipe))
 208                 notify_pipe[0] = notify_pipe[1] = -1;
 209
 210         cmd->pid = fork();
 211         if (!cmd->pid) {
 212                 /*
 213                  * Redirect the channel to write syscall error messages to
 214                  * before redirecting the process's stderr so that all die()
 215                  * in subsequent call paths use the parent's stderr.
 216                  */
 217                 if (cmd->no_stderr || need_err) {
 218                         child_err = dup(2);
 219                         set_cloexec(child_err);
 220                 }
 221                 set_die_routine(die_child);
 222
 223                 close(notify_pipe[0]);
 224                 set_cloexec(notify_pipe[1]);
 225                 child_notifier = notify_pipe[1];
 226                 atexit(notify_parent);
 227
 228                 if (cmd->no_stdin)
 229                         dup_devnull(0);
 230                 else if (need_in) {
 231                         dup2(fdin[0], 0);
 232                         close_pair(fdin);
 233                 } else if (cmd->in) {
 234                         dup2(cmd->in, 0);
 235                         close(cmd->in);
 236                 }
 237
 238                 if (cmd->no_stderr)
 239                         dup_devnull(2);
 240                 else if (need_err) {
 241                         dup2(fderr[1], 2);
 242                         close_pair(fderr);
 243                 } else if (cmd->err > 1) {
 244                         dup2(cmd->err, 2);
 245                         close(cmd->err);
 246                 }
 247
 248                 if (cmd->no_stdout)
 249                         dup_devnull(1);
 250                 else if (cmd->stdout_to_stderr)
 251                         dup2(2, 1);
 252                 else if (need_out) {
 253                         dup2(fdout[1], 1);
 254                         close_pair(fdout);
 255                 } else if (cmd->out > 1) {
 256                         dup2(cmd->out, 1);
 257                         close(cmd->out);
 258                 }
 259
 260                 if (cmd->dir && chdir(cmd->dir))
 261                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 262                             cmd->dir);
 263                 if (cmd->env) {
 264                         for (; *cmd->env; cmd->env++) {
 265                                 if (strchr(*cmd->env, '='))
 266                                         putenv((char *)*cmd->env);
 267                                 else
 268                                         unsetenv(*cmd->env);
 269                         }
 270                 }
 271                 if (cmd->preexec_cb) {
 272                         /*
 273                          * We cannot predict what the pre-exec callback does.
 274                          * Forgo parent notification.
 275                          */
 276                         close(child_notifier);
 277                         child_notifier = -1;
 278
 279                         cmd->preexec_cb();
 280                 }
 281                 if (cmd->git_cmd) {
 282                         execv_git_cmd(cmd->argv);
 283                 } else if (cmd->use_shell) {
 284                         execv_shell_cmd(cmd->argv);
 285                 } else {
 286                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 287                 }
 288                 /*
 289                  * Do not check for cmd->silent_exec_failure; the parent
 290                  * process will check it when it sees this exit code.
 291                  */
 292                 if (errno == ENOENT)
 293                         exit(127);
 294                 else
 295                         die_errno("cannot exec '%s'", cmd->argv[0]);
 296         }
 297         if (cmd->pid < 0)
 298                 error("cannot fork() for %s: %s", cmd->argv[0],
 299                         strerror(failed_errno = errno));
 300
 301         /*
 302          * Wait for child's execvp. If the execvp succeeds (or if fork()
 303          * failed), EOF is seen immediately by the parent. Otherwise, the
 304          * child process sends a single byte.
 305          * Note that use of this infrastructure is completely advisory,
 306          * therefore, we keep error checks minimal.
 307          */
 308         close(notify_pipe[1]);
 309         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 310                 /*
 311                  * At this point we know that fork() succeeded, but execvp()
 312                  * failed. Errors have been reported to our stderr.
 313                  */
 314                 wait_or_whine(cmd->pid, cmd->argv[0],
 315                               cmd->silent_exec_failure);
 316                 failed_errno = errno;
 317                 cmd->pid = -1;
 318         }
 319         close(notify_pipe[0]);
 320 }
 321 #else
 322 {
 323         int fhin = 0, fhout = 1, fherr = 2;
 324         const char **sargv = cmd->argv;
 325         char **env = environ;
 326
 327         if (cmd->no_stdin)
 328                 fhin = open("/dev/null", O_RDWR);
 329         else if (need_in)
 330                 fhin = dup(fdin[0]);
 331         else if (cmd->in)
 332                 fhin = dup(cmd->in);
 333
 334         if (cmd->no_stderr)
 335                 fherr = open("/dev/null", O_RDWR);
 336         else if (need_err)
 337                 fherr = dup(fderr[1]);
 338         else if (cmd->err > 2)
 339                 fherr = dup(cmd->err);
 340
 341         if (cmd->no_stdout)
 342                 fhout = open("/dev/null", O_RDWR);
 343         else if (cmd->stdout_to_stderr)
 344                 fhout = dup(fherr);
 345         else if (need_out)
 346                 fhout = dup(fdout[1]);
 347         else if (cmd->out > 1)
 348                 fhout = dup(cmd->out);
 349
 350         if (cmd->env)
 351                 env = make_augmented_environ(cmd->env);
 352
 353         if (cmd->git_cmd) {
 354                 cmd->argv = prepare_git_cmd(cmd->argv);
 355         } else if (cmd->use_shell) {
 356                 cmd->argv = prepare_shell_cmd(cmd->argv);
 357         }
 358
 359         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env, cmd->dir,
 360                                   fhin, fhout, fherr);
 361         failed_errno = errno;
 362         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 363                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 364
 365         if (cmd->env)
 366                 free_environ(env);
 367         if (cmd->git_cmd)
 368                 free(cmd->argv);
 369
 370         cmd->argv = sargv;
 371         if (fhin != 0)
 372                 close(fhin);
 373         if (fhout != 1)
 374                 close(fhout);
 375         if (fherr != 2)
 376                 close(fherr);
 377 }
 378 #endif
 379
 380         if (cmd->pid < 0) {
 381                 if (need_in)
 382                         close_pair(fdin);
 383                 else if (cmd->in)
 384                         close(cmd->in);
 385                 if (need_out)
 386                         close_pair(fdout);
 387                 else if (cmd->out)
 388                         close(cmd->out);
 389                 if (need_err)
 390                         close_pair(fderr);
 391                 else if (cmd->err)
 392                         close(cmd->err);
 393                 errno = failed_errno;
 394                 return -1;
 395         }
 396
 397         if (need_in)
 398                 close(fdin[0]);
 399         else if (cmd->in)
 400                 close(cmd->in);
 401
 402         if (need_out)
 403                 close(fdout[1]);
 404         else if (cmd->out)
 405                 close(cmd->out);
 406
 407         if (need_err)
 408                 close(fderr[1]);
 409         else if (cmd->err)
 410                 close(cmd->err);
 411
 412         return 0;
 413 }
 414
 415 int finish_command(struct child_process *cmd)
 416 {
 417         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 418 }
 419
 420 int run_command(struct child_process *cmd)
 421 {
 422         int code = start_command(cmd);
 423         if (code)
 424                 return code;
 425         return finish_command(cmd);
 426 }
 427
 428 static void prepare_run_command_v_opt(struct child_process *cmd,
 429                                       const char **argv,
 430                                       int opt)
 431 {
 432         memset(cmd, 0, sizeof(*cmd));
 433         cmd->argv = argv;
 434         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 435         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 436         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 437         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 438         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 439 }
 440
 441 int run_command_v_opt(const char **argv, int opt)
 442 {
 443         struct child_process cmd;
 444         prepare_run_command_v_opt(&cmd, argv, opt);
 445         return run_command(&cmd);
 446 }
 447
 448 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 449 {
 450         struct child_process cmd;
 451         prepare_run_command_v_opt(&cmd, argv, opt);
 452         cmd.dir = dir;
 453         cmd.env = env;
 454         return run_command(&cmd);
 455 }
 456
 457 #ifndef NO_PTHREADS
 458 static pthread_t main_thread;
 459 static int main_thread_set;
 460 static pthread_key_t async_key;
 461
 462 static void *run_thread(void *data)
 463 {
 464         struct async *async = data;
 465         intptr_t ret;
 466
 467         pthread_setspecific(async_key, async);
 468         ret = async->proc(async->proc_in, async->proc_out, async->data);
 469         return (void *)ret;
 470 }
 471
 472 static NORETURN void die_async(const char *err, va_list params)
 473 {
 474         vreportf("fatal: ", err, params);
 475
 476         if (!pthread_equal(main_thread, pthread_self())) {
 477                 struct async *async = pthread_getspecific(async_key);
 478                 if (async->proc_in >= 0)
 479                         close(async->proc_in);
 480                 if (async->proc_out >= 0)
 481                         close(async->proc_out);
 482                 pthread_exit((void *)128);
 483         }
 484
 485         exit(128);
 486 }
 487 #endif
 488
 489 int start_async(struct async *async)
 490 {
 491         int need_in, need_out;
 492         int fdin[2], fdout[2];
 493         int proc_in, proc_out;
 494
 495         need_in = async->in < 0;
 496         if (need_in) {
 497                 if (pipe(fdin) < 0) {
 498                         if (async->out > 0)
 499                                 close(async->out);
 500                         return error("cannot create pipe: %s", strerror(errno));
 501                 }
 502                 async->in = fdin[1];
 503         }
 504
 505         need_out = async->out < 0;
 506         if (need_out) {
 507                 if (pipe(fdout) < 0) {
 508                         if (need_in)
 509                                 close_pair(fdin);
 510                         else if (async->in)
 511                                 close(async->in);
 512                         return error("cannot create pipe: %s", strerror(errno));
 513                 }
 514                 async->out = fdout[0];
 515         }
 516
 517         if (need_in)
 518                 proc_in = fdin[0];
 519         else if (async->in)
 520                 proc_in = async->in;
 521         else
 522                 proc_in = -1;
 523
 524         if (need_out)
 525                 proc_out = fdout[1];
 526         else if (async->out)
 527                 proc_out = async->out;
 528         else
 529                 proc_out = -1;
 530
 531 #ifdef NO_PTHREADS
 532         /* Flush stdio before fork() to avoid cloning buffers */
 533         fflush(NULL);
 534
 535         async->pid = fork();
 536         if (async->pid < 0) {
 537                 error("fork (async) failed: %s", strerror(errno));
 538                 goto error;
 539         }
 540         if (!async->pid) {
 541                 if (need_in)
 542                         close(fdin[1]);
 543                 if (need_out)
 544                         close(fdout[0]);
 545                 exit(!!async->proc(proc_in, proc_out, async->data));
 546         }
 547
 548         if (need_in)
 549                 close(fdin[0]);
 550         else if (async->in)
 551                 close(async->in);
 552
 553         if (need_out)
 554                 close(fdout[1]);
 555         else if (async->out)
 556                 close(async->out);
 557 #else
 558         if (!main_thread_set) {
 559                 /*
 560                  * We assume that the first time that start_async is called
 561                  * it is from the main thread.
 562                  */
 563                 main_thread_set = 1;
 564                 main_thread = pthread_self();
 565                 pthread_key_create(&async_key, NULL);
 566                 set_die_routine(die_async);
 567         }
 568
 569         if (proc_in >= 0)
 570                 set_cloexec(proc_in);
 571         if (proc_out >= 0)
 572                 set_cloexec(proc_out);
 573         async->proc_in = proc_in;
 574         async->proc_out = proc_out;
 575         {
 576                 int err = pthread_create(&async->tid, NULL, run_thread, async);
 577                 if (err) {
 578                         error("cannot create thread: %s", strerror(err));
 579                         goto error;
 580                 }
 581         }
 582 #endif
 583         return 0;
 584
 585 error:
 586         if (need_in)
 587                 close_pair(fdin);
 588         else if (async->in)
 589                 close(async->in);
 590
 591         if (need_out)
 592                 close_pair(fdout);
 593         else if (async->out)
 594                 close(async->out);
 595         return -1;
 596 }
 597
 598 int finish_async(struct async *async)
 599 {
 600 #ifdef NO_PTHREADS
 601         return wait_or_whine(async->pid, "child process", 0);
 602 #else
 603         void *ret = (void *)(intptr_t)(-1);
 604
 605         if (pthread_join(async->tid, &ret))
 606                 error("pthread_join failed");
 607         return (int)(intptr_t)ret;
 608 #endif
 609 }
 610
 611 int run_hook(const char *index_file, const char *name, ...)
 612 {
 613         struct child_process hook;
 614         const char **argv = NULL, *env[2];
 615         char index[PATH_MAX];
 616         va_list args;
 617         int ret;
 618         size_t i = 0, alloc = 0;
 619
 620         if (access(git_path("hooks/%s", name), X_OK) < 0)
 621                 return 0;
 622
 623         va_start(args, name);
 624         ALLOC_GROW(argv, i + 1, alloc);
 625         argv[i++] = git_path("hooks/%s", name);
 626         while (argv[i-1]) {
 627                 ALLOC_GROW(argv, i + 1, alloc);
 628                 argv[i++] = va_arg(args, const char *);
 629         }
 630         va_end(args);
 631
 632         memset(&hook, 0, sizeof(hook));
 633         hook.argv = argv;
 634         hook.no_stdin = 1;
 635         hook.stdout_to_stderr = 1;
 636         if (index_file) {
 637                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 638                 env[0] = index;
 639                 env[1] = NULL;
 640                 hook.env = env;
 641         }
 642
 643         ret = run_command(&hook);
 644         free(argv);
 645         return ret;
 646 }