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         vwritef(child_err, "fatal: ", err, params);
  82         exit(128);
  83 }
  84
  85 static void error_child(const char *err, va_list params)
  86 {
  87         vwritef(child_err, "error: ", err, params);
  88 }
  89 #endif
  90
  91 static inline void set_cloexec(int fd)
  92 {
  93         int flags = fcntl(fd, F_GETFD);
  94         if (flags >= 0)
  95                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
  96 }
  97
  98 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
  99 {
 100         int status, code = -1;
 101         pid_t waiting;
 102         int failed_errno = 0;
 103
 104         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 105                 ;       /* nothing */
 106
 107         if (waiting < 0) {
 108                 failed_errno = errno;
 109                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 110         } else if (waiting != pid) {
 111                 error("waitpid is confused (%s)", argv0);
 112         } else if (WIFSIGNALED(status)) {
 113                 code = WTERMSIG(status);
 114                 error("%s died of signal %d", argv0, code);
 115                 /*
 116                  * This return value is chosen so that code & 0xff
 117                  * mimics the exit code that a POSIX shell would report for
 118                  * a program that died from this signal.
 119                  */
 120                 code -= 128;
 121         } else if (WIFEXITED(status)) {
 122                 code = WEXITSTATUS(status);
 123                 /*
 124                  * Convert special exit code when execvp failed.
 125                  */
 126                 if (code == 127) {
 127                         code = -1;
 128                         failed_errno = ENOENT;
 129                 }
 130         } else {
 131                 error("waitpid is confused (%s)", argv0);
 132         }
 133         errno = failed_errno;
 134         return code;
 135 }
 136
 137 int start_command(struct child_process *cmd)
 138 {
 139         int need_in, need_out, need_err;
 140         int fdin[2], fdout[2], fderr[2];
 141         int failed_errno = failed_errno;
 142
 143         /*
 144          * In case of errors we must keep the promise to close FDs
 145          * that have been passed in via ->in and ->out.
 146          */
 147
 148         need_in = !cmd->no_stdin && cmd->in < 0;
 149         if (need_in) {
 150                 if (pipe(fdin) < 0) {
 151                         failed_errno = errno;
 152                         if (cmd->out > 0)
 153                                 close(cmd->out);
 154                         goto fail_pipe;
 155                 }
 156                 cmd->in = fdin[1];
 157         }
 158
 159         need_out = !cmd->no_stdout
 160                 && !cmd->stdout_to_stderr
 161                 && cmd->out < 0;
 162         if (need_out) {
 163                 if (pipe(fdout) < 0) {
 164                         failed_errno = errno;
 165                         if (need_in)
 166                                 close_pair(fdin);
 167                         else if (cmd->in)
 168                                 close(cmd->in);
 169                         goto fail_pipe;
 170                 }
 171                 cmd->out = fdout[0];
 172         }
 173
 174         need_err = !cmd->no_stderr && cmd->err < 0;
 175         if (need_err) {
 176                 if (pipe(fderr) < 0) {
 177                         failed_errno = errno;
 178                         if (need_in)
 179                                 close_pair(fdin);
 180                         else if (cmd->in)
 181                                 close(cmd->in);
 182                         if (need_out)
 183                                 close_pair(fdout);
 184                         else if (cmd->out)
 185                                 close(cmd->out);
 186 fail_pipe:
 187                         error("cannot create pipe for %s: %s",
 188                                 cmd->argv[0], strerror(failed_errno));
 189                         errno = failed_errno;
 190                         return -1;
 191                 }
 192                 cmd->err = fderr[0];
 193         }
 194
 195         trace_argv_printf(cmd->argv, "trace: run_command:");
 196         fflush(NULL);
 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         cmd->pid = fork();
 205         if (!cmd->pid) {
 206                 /*
 207                  * Redirect the channel to write syscall error messages to
 208                  * before redirecting the process's stderr so that all die()
 209                  * in subsequent call paths use the parent's stderr.
 210                  */
 211                 if (cmd->no_stderr || need_err) {
 212                         child_err = dup(2);
 213                         set_cloexec(child_err);
 214                 }
 215                 set_die_routine(die_child);
 216                 set_error_routine(error_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                 if (errno == ENOENT) {
 284                         if (!cmd->silent_exec_failure)
 285                                 error("cannot run %s: %s", cmd->argv[0],
 286                                         strerror(ENOENT));
 287                         exit(127);
 288                 } else {
 289                         die_errno("cannot exec '%s'", cmd->argv[0]);
 290                 }
 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         struct argv_array argv = ARGV_ARRAY_INIT;
 610         const char *p, *env[2];
 611         char index[PATH_MAX];
 612         va_list args;
 613         int ret;
 614
 615         if (access(git_path("hooks/%s", name), X_OK) < 0)
 616                 return 0;
 617
 618         va_start(args, name);
 619         argv_array_push(&argv, git_path("hooks/%s", name));
 620         while ((p = va_arg(args, const char *)))
 621                 argv_array_push(&argv, p);
 622         va_end(args);
 623
 624         memset(&hook, 0, sizeof(hook));
 625         hook.argv = argv.argv;
 626         hook.no_stdin = 1;
 627         hook.stdout_to_stderr = 1;
 628         if (index_file) {
 629                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 630                 env[0] = index;
 631                 env[1] = NULL;
 632                 hook.env = env;
 633         }
 634
 635         ret = run_command(&hook);
 636         argv_array_clear(&argv);
 637         return ret;
 638 }