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 static inline void dup_devnull(int to)
  12 {
  13         int fd = open("/dev/null", O_RDWR);
  14         dup2(fd, to);
  15         close(fd);
  16 }
  17
  18 #ifndef WIN32
  19 static int child_err = 2;
  20
  21 static NORETURN void die_child(const char *err, va_list params)
  22 {
  23         char msg[4096];
  24         int len = vsnprintf(msg, sizeof(msg), err, params);
  25         if (len > sizeof(msg))
  26                 len = sizeof(msg);
  27
  28         write(child_err, "fatal: ", 7);
  29         write(child_err, msg, len);
  30         write(child_err, "\n", 1);
  31         exit(128);
  32 }
  33
  34 static inline void set_cloexec(int fd)
  35 {
  36         int flags = fcntl(fd, F_GETFD);
  37         if (flags >= 0)
  38                 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
  39 }
  40 #endif
  41
  42 int start_command(struct child_process *cmd)
  43 {
  44         int need_in, need_out, need_err;
  45         int fdin[2], fdout[2], fderr[2];
  46         int failed_errno = failed_errno;
  47
  48         /*
  49          * In case of errors we must keep the promise to close FDs
  50          * that have been passed in via ->in and ->out.
  51          */
  52
  53         need_in = !cmd->no_stdin && cmd->in < 0;
  54         if (need_in) {
  55                 if (pipe(fdin) < 0) {
  56                         failed_errno = errno;
  57                         if (cmd->out > 0)
  58                                 close(cmd->out);
  59                         goto fail_pipe;
  60                 }
  61                 cmd->in = fdin[1];
  62         }
  63
  64         need_out = !cmd->no_stdout
  65                 && !cmd->stdout_to_stderr
  66                 && cmd->out < 0;
  67         if (need_out) {
  68                 if (pipe(fdout) < 0) {
  69                         failed_errno = errno;
  70                         if (need_in)
  71                                 close_pair(fdin);
  72                         else if (cmd->in)
  73                                 close(cmd->in);
  74                         goto fail_pipe;
  75                 }
  76                 cmd->out = fdout[0];
  77         }
  78
  79         need_err = !cmd->no_stderr && cmd->err < 0;
  80         if (need_err) {
  81                 if (pipe(fderr) < 0) {
  82                         failed_errno = errno;
  83                         if (need_in)
  84                                 close_pair(fdin);
  85                         else if (cmd->in)
  86                                 close(cmd->in);
  87                         if (need_out)
  88                                 close_pair(fdout);
  89                         else if (cmd->out)
  90                                 close(cmd->out);
  91 fail_pipe:
  92                         error("cannot create pipe for %s: %s",
  93                                 cmd->argv[0], strerror(failed_errno));
  94                         errno = failed_errno;
  95                         return -1;
  96                 }
  97                 cmd->err = fderr[0];
  98         }
  99
 100         trace_argv_printf(cmd->argv, "trace: run_command:");
 101
 102 #ifndef WIN32
 103         fflush(NULL);
 104         cmd->pid = fork();
 105         if (!cmd->pid) {
 106                 /*
 107                  * Redirect the channel to write syscall error messages to
 108                  * before redirecting the process's stderr so that all die()
 109                  * in subsequent call paths use the parent's stderr.
 110                  */
 111                 if (cmd->no_stderr || need_err) {
 112                         child_err = dup(2);
 113                         set_cloexec(child_err);
 114                 }
 115                 set_die_routine(die_child);
 116
 117                 if (cmd->no_stdin)
 118                         dup_devnull(0);
 119                 else if (need_in) {
 120                         dup2(fdin[0], 0);
 121                         close_pair(fdin);
 122                 } else if (cmd->in) {
 123                         dup2(cmd->in, 0);
 124                         close(cmd->in);
 125                 }
 126
 127                 if (cmd->no_stderr)
 128                         dup_devnull(2);
 129                 else if (need_err) {
 130                         dup2(fderr[1], 2);
 131                         close_pair(fderr);
 132                 }
 133
 134                 if (cmd->no_stdout)
 135                         dup_devnull(1);
 136                 else if (cmd->stdout_to_stderr)
 137                         dup2(2, 1);
 138                 else if (need_out) {
 139                         dup2(fdout[1], 1);
 140                         close_pair(fdout);
 141                 } else if (cmd->out > 1) {
 142                         dup2(cmd->out, 1);
 143                         close(cmd->out);
 144                 }
 145
 146                 if (cmd->dir && chdir(cmd->dir))
 147                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 148                             cmd->dir);
 149                 if (cmd->env) {
 150                         for (; *cmd->env; cmd->env++) {
 151                                 if (strchr(*cmd->env, '='))
 152                                         putenv((char *)*cmd->env);
 153                                 else
 154                                         unsetenv(*cmd->env);
 155                         }
 156                 }
 157                 if (cmd->preexec_cb)
 158                         cmd->preexec_cb();
 159                 if (cmd->git_cmd) {
 160                         execv_git_cmd(cmd->argv);
 161                 } else {
 162                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 163                 }
 164                 /*
 165                  * Do not check for cmd->silent_exec_failure; the parent
 166                  * process will check it when it sees this exit code.
 167                  */
 168                 if (errno == ENOENT)
 169                         exit(127);
 170                 else
 171                         die_errno("cannot exec '%s'", cmd->argv[0]);
 172         }
 173         if (cmd->pid < 0)
 174                 error("cannot fork() for %s: %s", cmd->argv[0],
 175                         strerror(failed_errno = errno));
 176 #else
 177 {
 178         int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
 179         const char **sargv = cmd->argv;
 180         char **env = environ;
 181
 182         if (cmd->no_stdin) {
 183                 s0 = dup(0);
 184                 dup_devnull(0);
 185         } else if (need_in) {
 186                 s0 = dup(0);
 187                 dup2(fdin[0], 0);
 188         } else if (cmd->in) {
 189                 s0 = dup(0);
 190                 dup2(cmd->in, 0);
 191         }
 192
 193         if (cmd->no_stderr) {
 194                 s2 = dup(2);
 195                 dup_devnull(2);
 196         } else if (need_err) {
 197                 s2 = dup(2);
 198                 dup2(fderr[1], 2);
 199         }
 200
 201         if (cmd->no_stdout) {
 202                 s1 = dup(1);
 203                 dup_devnull(1);
 204         } else if (cmd->stdout_to_stderr) {
 205                 s1 = dup(1);
 206                 dup2(2, 1);
 207         } else if (need_out) {
 208                 s1 = dup(1);
 209                 dup2(fdout[1], 1);
 210         } else if (cmd->out > 1) {
 211                 s1 = dup(1);
 212                 dup2(cmd->out, 1);
 213         }
 214
 215         if (cmd->dir)
 216                 die("chdir in start_command() not implemented");
 217         if (cmd->env)
 218                 env = make_augmented_environ(cmd->env);
 219
 220         if (cmd->git_cmd) {
 221                 cmd->argv = prepare_git_cmd(cmd->argv);
 222         }
 223
 224         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
 225         failed_errno = errno;
 226         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 227                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 228
 229         if (cmd->env)
 230                 free_environ(env);
 231         if (cmd->git_cmd)
 232                 free(cmd->argv);
 233
 234         cmd->argv = sargv;
 235         if (s0 >= 0)
 236                 dup2(s0, 0), close(s0);
 237         if (s1 >= 0)
 238                 dup2(s1, 1), close(s1);
 239         if (s2 >= 0)
 240                 dup2(s2, 2), close(s2);
 241 }
 242 #endif
 243
 244         if (cmd->pid < 0) {
 245                 if (need_in)
 246                         close_pair(fdin);
 247                 else if (cmd->in)
 248                         close(cmd->in);
 249                 if (need_out)
 250                         close_pair(fdout);
 251                 else if (cmd->out)
 252                         close(cmd->out);
 253                 if (need_err)
 254                         close_pair(fderr);
 255                 errno = failed_errno;
 256                 return -1;
 257         }
 258
 259         if (need_in)
 260                 close(fdin[0]);
 261         else if (cmd->in)
 262                 close(cmd->in);
 263
 264         if (need_out)
 265                 close(fdout[1]);
 266         else if (cmd->out)
 267                 close(cmd->out);
 268
 269         if (need_err)
 270                 close(fderr[1]);
 271
 272         return 0;
 273 }
 274
 275 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 276 {
 277         int status, code = -1;
 278         pid_t waiting;
 279         int failed_errno = 0;
 280
 281         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 282                 ;       /* nothing */
 283
 284         if (waiting < 0) {
 285                 failed_errno = errno;
 286                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 287         } else if (waiting != pid) {
 288                 error("waitpid is confused (%s)", argv0);
 289         } else if (WIFSIGNALED(status)) {
 290                 code = WTERMSIG(status);
 291                 error("%s died of signal %d", argv0, code);
 292                 /*
 293                  * This return value is chosen so that code & 0xff
 294                  * mimics the exit code that a POSIX shell would report for
 295                  * a program that died from this signal.
 296                  */
 297                 code -= 128;
 298         } else if (WIFEXITED(status)) {
 299                 code = WEXITSTATUS(status);
 300                 /*
 301                  * Convert special exit code when execvp failed.
 302                  */
 303                 if (code == 127) {
 304                         code = -1;
 305                         failed_errno = ENOENT;
 306                         if (!silent_exec_failure)
 307                                 error("cannot run %s: %s", argv0,
 308                                         strerror(ENOENT));
 309                 }
 310         } else {
 311                 error("waitpid is confused (%s)", argv0);
 312         }
 313         errno = failed_errno;
 314         return code;
 315 }
 316
 317 int finish_command(struct child_process *cmd)
 318 {
 319         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 320 }
 321
 322 int run_command(struct child_process *cmd)
 323 {
 324         int code = start_command(cmd);
 325         if (code)
 326                 return code;
 327         return finish_command(cmd);
 328 }
 329
 330 static void prepare_run_command_v_opt(struct child_process *cmd,
 331                                       const char **argv,
 332                                       int opt)
 333 {
 334         memset(cmd, 0, sizeof(*cmd));
 335         cmd->argv = argv;
 336         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 337         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 338         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 339         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 340 }
 341
 342 int run_command_v_opt(const char **argv, int opt)
 343 {
 344         struct child_process cmd;
 345         prepare_run_command_v_opt(&cmd, argv, opt);
 346         return run_command(&cmd);
 347 }
 348
 349 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 350 {
 351         struct child_process cmd;
 352         prepare_run_command_v_opt(&cmd, argv, opt);
 353         cmd.dir = dir;
 354         cmd.env = env;
 355         return run_command(&cmd);
 356 }
 357
 358 #ifdef WIN32
 359 static unsigned __stdcall run_thread(void *data)
 360 {
 361         struct async *async = data;
 362         return async->proc(async->fd_for_proc, async->data);
 363 }
 364 #endif
 365
 366 int start_async(struct async *async)
 367 {
 368         int pipe_out[2];
 369
 370         if (pipe(pipe_out) < 0)
 371                 return error("cannot create pipe: %s", strerror(errno));
 372         async->out = pipe_out[0];
 373
 374 #ifndef WIN32
 375         /* Flush stdio before fork() to avoid cloning buffers */
 376         fflush(NULL);
 377
 378         async->pid = fork();
 379         if (async->pid < 0) {
 380                 error("fork (async) failed: %s", strerror(errno));
 381                 close_pair(pipe_out);
 382                 return -1;
 383         }
 384         if (!async->pid) {
 385                 close(pipe_out[0]);
 386                 exit(!!async->proc(pipe_out[1], async->data));
 387         }
 388         close(pipe_out[1]);
 389 #else
 390         async->fd_for_proc = pipe_out[1];
 391         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 392         if (!async->tid) {
 393                 error("cannot create thread: %s", strerror(errno));
 394                 close_pair(pipe_out);
 395                 return -1;
 396         }
 397 #endif
 398         return 0;
 399 }
 400
 401 int finish_async(struct async *async)
 402 {
 403 #ifndef WIN32
 404         int ret = wait_or_whine(async->pid, "child process", 0);
 405 #else
 406         DWORD ret = 0;
 407         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 408                 ret = error("waiting for thread failed: %lu", GetLastError());
 409         else if (!GetExitCodeThread(async->tid, &ret))
 410                 ret = error("cannot get thread exit code: %lu", GetLastError());
 411         CloseHandle(async->tid);
 412 #endif
 413         return ret;
 414 }
 415
 416 int run_hook(const char *index_file, const char *name, ...)
 417 {
 418         struct child_process hook;
 419         const char **argv = NULL, *env[2];
 420         char index[PATH_MAX];
 421         va_list args;
 422         int ret;
 423         size_t i = 0, alloc = 0;
 424
 425         if (access(git_path("hooks/%s", name), X_OK) < 0)
 426                 return 0;
 427
 428         va_start(args, name);
 429         ALLOC_GROW(argv, i + 1, alloc);
 430         argv[i++] = git_path("hooks/%s", name);
 431         while (argv[i-1]) {
 432                 ALLOC_GROW(argv, i + 1, alloc);
 433                 argv[i++] = va_arg(args, const char *);
 434         }
 435         va_end(args);
 436
 437         memset(&hook, 0, sizeof(hook));
 438         hook.argv = argv;
 439         hook.no_stdin = 1;
 440         hook.stdout_to_stderr = 1;
 441         if (index_file) {
 442                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 443                 env[0] = index;
 444                 env[1] = NULL;
 445                 hook.env = env;
 446         }
 447
 448         ret = run_command(&hook);
 449         free(argv);
 450         return ret;
 451 }