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
  86 static inline void set_cloexec(int fd)
  87 {
  88         int flags = fcntl(fd, F_GETFD);
  89         if (flags >= 0)
  90                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
  91 }
  92 #endif
  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                 }
 237
 238                 if (cmd->no_stdout)
 239                         dup_devnull(1);
 240                 else if (cmd->stdout_to_stderr)
 241                         dup2(2, 1);
 242                 else if (need_out) {
 243                         dup2(fdout[1], 1);
 244                         close_pair(fdout);
 245                 } else if (cmd->out > 1) {
 246                         dup2(cmd->out, 1);
 247                         close(cmd->out);
 248                 }
 249
 250                 if (cmd->dir && chdir(cmd->dir))
 251                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 252                             cmd->dir);
 253                 if (cmd->env) {
 254                         for (; *cmd->env; cmd->env++) {
 255                                 if (strchr(*cmd->env, '='))
 256                                         putenv((char *)*cmd->env);
 257                                 else
 258                                         unsetenv(*cmd->env);
 259                         }
 260                 }
 261                 if (cmd->preexec_cb) {
 262                         /*
 263                          * We cannot predict what the pre-exec callback does.
 264                          * Forgo parent notification.
 265                          */
 266                         close(child_notifier);
 267                         child_notifier = -1;
 268
 269                         cmd->preexec_cb();
 270                 }
 271                 if (cmd->git_cmd) {
 272                         execv_git_cmd(cmd->argv);
 273                 } else if (cmd->use_shell) {
 274                         execv_shell_cmd(cmd->argv);
 275                 } else {
 276                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 277                 }
 278                 /*
 279                  * Do not check for cmd->silent_exec_failure; the parent
 280                  * process will check it when it sees this exit code.
 281                  */
 282                 if (errno == ENOENT)
 283                         exit(127);
 284                 else
 285                         die_errno("cannot exec '%s'", cmd->argv[0]);
 286         }
 287         if (cmd->pid < 0)
 288                 error("cannot fork() for %s: %s", cmd->argv[0],
 289                         strerror(failed_errno = errno));
 290
 291         /*
 292          * Wait for child's execvp. If the execvp succeeds (or if fork()
 293          * failed), EOF is seen immediately by the parent. Otherwise, the
 294          * child process sends a single byte.
 295          * Note that use of this infrastructure is completely advisory,
 296          * therefore, we keep error checks minimal.
 297          */
 298         close(notify_pipe[1]);
 299         if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
 300                 /*
 301                  * At this point we know that fork() succeeded, but execvp()
 302                  * failed. Errors have been reported to our stderr.
 303                  */
 304                 wait_or_whine(cmd->pid, cmd->argv[0],
 305                               cmd->silent_exec_failure);
 306                 failed_errno = errno;
 307                 cmd->pid = -1;
 308         }
 309         close(notify_pipe[0]);
 310 }
 311 #else
 312 {
 313         int fhin = 0, fhout = 1, fherr = 2;
 314         const char **sargv = cmd->argv;
 315         char **env = environ;
 316
 317         if (cmd->no_stdin)
 318                 fhin = open("/dev/null", O_RDWR);
 319         else if (need_in)
 320                 fhin = dup(fdin[0]);
 321         else if (cmd->in)
 322                 fhin = dup(cmd->in);
 323
 324         if (cmd->no_stderr)
 325                 fherr = open("/dev/null", O_RDWR);
 326         else if (need_err)
 327                 fherr = dup(fderr[1]);
 328
 329         if (cmd->no_stdout)
 330                 fhout = open("/dev/null", O_RDWR);
 331         else if (cmd->stdout_to_stderr)
 332                 fhout = dup(fherr);
 333         else if (need_out)
 334                 fhout = dup(fdout[1]);
 335         else if (cmd->out > 1)
 336                 fhout = dup(cmd->out);
 337
 338         if (cmd->dir)
 339                 die("chdir in start_command() not implemented");
 340         if (cmd->env)
 341                 env = make_augmented_environ(cmd->env);
 342
 343         if (cmd->git_cmd) {
 344                 cmd->argv = prepare_git_cmd(cmd->argv);
 345         } else if (cmd->use_shell) {
 346                 cmd->argv = prepare_shell_cmd(cmd->argv);
 347         }
 348
 349         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env,
 350                                   fhin, fhout, fherr);
 351         failed_errno = errno;
 352         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 353                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 354
 355         if (cmd->env)
 356                 free_environ(env);
 357         if (cmd->git_cmd)
 358                 free(cmd->argv);
 359
 360         cmd->argv = sargv;
 361         if (fhin != 0)
 362                 close(fhin);
 363         if (fhout != 1)
 364                 close(fhout);
 365         if (fherr != 2)
 366                 close(fherr);
 367 }
 368 #endif
 369
 370         if (cmd->pid < 0) {
 371                 if (need_in)
 372                         close_pair(fdin);
 373                 else if (cmd->in)
 374                         close(cmd->in);
 375                 if (need_out)
 376                         close_pair(fdout);
 377                 else if (cmd->out)
 378                         close(cmd->out);
 379                 if (need_err)
 380                         close_pair(fderr);
 381                 errno = failed_errno;
 382                 return -1;
 383         }
 384
 385         if (need_in)
 386                 close(fdin[0]);
 387         else if (cmd->in)
 388                 close(cmd->in);
 389
 390         if (need_out)
 391                 close(fdout[1]);
 392         else if (cmd->out)
 393                 close(cmd->out);
 394
 395         if (need_err)
 396                 close(fderr[1]);
 397
 398         return 0;
 399 }
 400
 401 int finish_command(struct child_process *cmd)
 402 {
 403         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 404 }
 405
 406 int run_command(struct child_process *cmd)
 407 {
 408         int code = start_command(cmd);
 409         if (code)
 410                 return code;
 411         return finish_command(cmd);
 412 }
 413
 414 static void prepare_run_command_v_opt(struct child_process *cmd,
 415                                       const char **argv,
 416                                       int opt)
 417 {
 418         memset(cmd, 0, sizeof(*cmd));
 419         cmd->argv = argv;
 420         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 421         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 422         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 423         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 424         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 425 }
 426
 427 int run_command_v_opt(const char **argv, int opt)
 428 {
 429         struct child_process cmd;
 430         prepare_run_command_v_opt(&cmd, argv, opt);
 431         return run_command(&cmd);
 432 }
 433
 434 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 435 {
 436         struct child_process cmd;
 437         prepare_run_command_v_opt(&cmd, argv, opt);
 438         cmd.dir = dir;
 439         cmd.env = env;
 440         return run_command(&cmd);
 441 }
 442
 443 #ifdef WIN32
 444 static unsigned __stdcall run_thread(void *data)
 445 {
 446         struct async *async = data;
 447         return async->proc(async->fd_for_proc, async->data);
 448 }
 449 #endif
 450
 451 int start_async(struct async *async)
 452 {
 453         int pipe_out[2];
 454
 455         if (pipe(pipe_out) < 0)
 456                 return error("cannot create pipe: %s", strerror(errno));
 457         async->out = pipe_out[0];
 458
 459 #ifndef WIN32
 460         /* Flush stdio before fork() to avoid cloning buffers */
 461         fflush(NULL);
 462
 463         async->pid = fork();
 464         if (async->pid < 0) {
 465                 error("fork (async) failed: %s", strerror(errno));
 466                 close_pair(pipe_out);
 467                 return -1;
 468         }
 469         if (!async->pid) {
 470                 close(pipe_out[0]);
 471                 exit(!!async->proc(pipe_out[1], async->data));
 472         }
 473         close(pipe_out[1]);
 474 #else
 475         async->fd_for_proc = pipe_out[1];
 476         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 477         if (!async->tid) {
 478                 error("cannot create thread: %s", strerror(errno));
 479                 close_pair(pipe_out);
 480                 return -1;
 481         }
 482 #endif
 483         return 0;
 484 }
 485
 486 int finish_async(struct async *async)
 487 {
 488 #ifndef WIN32
 489         int ret = wait_or_whine(async->pid, "child process", 0);
 490 #else
 491         DWORD ret = 0;
 492         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 493                 ret = error("waiting for thread failed: %lu", GetLastError());
 494         else if (!GetExitCodeThread(async->tid, &ret))
 495                 ret = error("cannot get thread exit code: %lu", GetLastError());
 496         CloseHandle(async->tid);
 497 #endif
 498         return ret;
 499 }
 500
 501 int run_hook(const char *index_file, const char *name, ...)
 502 {
 503         struct child_process hook;
 504         const char **argv = NULL, *env[2];
 505         char index[PATH_MAX];
 506         va_list args;
 507         int ret;
 508         size_t i = 0, alloc = 0;
 509
 510         if (access(git_path("hooks/%s", name), X_OK) < 0)
 511                 return 0;
 512
 513         va_start(args, name);
 514         ALLOC_GROW(argv, i + 1, alloc);
 515         argv[i++] = git_path("hooks/%s", name);
 516         while (argv[i-1]) {
 517                 ALLOC_GROW(argv, i + 1, alloc);
 518                 argv[i++] = va_arg(args, const char *);
 519         }
 520         va_end(args);
 521
 522         memset(&hook, 0, sizeof(hook));
 523         hook.argv = argv;
 524         hook.no_stdin = 1;
 525         hook.stdout_to_stderr = 1;
 526         if (index_file) {
 527                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 528                 env[0] = index;
 529                 env[1] = NULL;
 530                 hook.env = env;
 531         }
 532
 533         ret = run_command(&hook);
 534         free(argv);
 535         return ret;
 536 }