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