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 static const char **prepare_shell_cmd(const char **argv)
  19 {
  20         int argc, nargc = 0;
  21         const char **nargv;
  22
  23         for (argc = 0; argv[argc]; argc++)
  24                 ; /* just counting */
  25         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
  26         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
  27
  28         if (argc < 1)
  29                 die("BUG: shell command is empty");
  30
  31         nargv[nargc++] = "sh";
  32         nargv[nargc++] = "-c";
  33
  34         if (argc < 2)
  35                 nargv[nargc++] = argv[0];
  36         else {
  37                 struct strbuf arg0 = STRBUF_INIT;
  38                 strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
  39                 nargv[nargc++] = strbuf_detach(&arg0, NULL);
  40         }
  41
  42         for (argc = 0; argv[argc]; argc++)
  43                 nargv[nargc++] = argv[argc];
  44         nargv[nargc] = NULL;
  45
  46         return nargv;
  47 }
  48
  49 #ifndef WIN32
  50 static int execv_shell_cmd(const char **argv)
  51 {
  52         const char **nargv = prepare_shell_cmd(argv);
  53         trace_argv_printf(nargv, "trace: exec:");
  54         execvp(nargv[0], (char **)nargv);
  55         free(nargv);
  56         return -1;
  57 }
  58 #endif
  59
  60 int start_command(struct child_process *cmd)
  61 {
  62         int need_in, need_out, need_err;
  63         int fdin[2], fdout[2], fderr[2];
  64         int failed_errno = failed_errno;
  65
  66         /*
  67          * In case of errors we must keep the promise to close FDs
  68          * that have been passed in via ->in and ->out.
  69          */
  70
  71         need_in = !cmd->no_stdin && cmd->in < 0;
  72         if (need_in) {
  73                 if (pipe(fdin) < 0) {
  74                         failed_errno = errno;
  75                         if (cmd->out > 0)
  76                                 close(cmd->out);
  77                         goto fail_pipe;
  78                 }
  79                 cmd->in = fdin[1];
  80         }
  81
  82         need_out = !cmd->no_stdout
  83                 && !cmd->stdout_to_stderr
  84                 && cmd->out < 0;
  85         if (need_out) {
  86                 if (pipe(fdout) < 0) {
  87                         failed_errno = errno;
  88                         if (need_in)
  89                                 close_pair(fdin);
  90                         else if (cmd->in)
  91                                 close(cmd->in);
  92                         goto fail_pipe;
  93                 }
  94                 cmd->out = fdout[0];
  95         }
  96
  97         need_err = !cmd->no_stderr && cmd->err < 0;
  98         if (need_err) {
  99                 if (pipe(fderr) < 0) {
 100                         failed_errno = errno;
 101                         if (need_in)
 102                                 close_pair(fdin);
 103                         else if (cmd->in)
 104                                 close(cmd->in);
 105                         if (need_out)
 106                                 close_pair(fdout);
 107                         else if (cmd->out)
 108                                 close(cmd->out);
 109 fail_pipe:
 110                         error("cannot create pipe for %s: %s",
 111                                 cmd->argv[0], strerror(failed_errno));
 112                         errno = failed_errno;
 113                         return -1;
 114                 }
 115                 cmd->err = fderr[0];
 116         }
 117
 118         trace_argv_printf(cmd->argv, "trace: run_command:");
 119
 120 #ifndef WIN32
 121         fflush(NULL);
 122         cmd->pid = fork();
 123         if (!cmd->pid) {
 124                 if (cmd->no_stdin)
 125                         dup_devnull(0);
 126                 else if (need_in) {
 127                         dup2(fdin[0], 0);
 128                         close_pair(fdin);
 129                 } else if (cmd->in) {
 130                         dup2(cmd->in, 0);
 131                         close(cmd->in);
 132                 }
 133
 134                 if (cmd->no_stderr)
 135                         dup_devnull(2);
 136                 else if (need_err) {
 137                         dup2(fderr[1], 2);
 138                         close_pair(fderr);
 139                 }
 140
 141                 if (cmd->no_stdout)
 142                         dup_devnull(1);
 143                 else if (cmd->stdout_to_stderr)
 144                         dup2(2, 1);
 145                 else if (need_out) {
 146                         dup2(fdout[1], 1);
 147                         close_pair(fdout);
 148                 } else if (cmd->out > 1) {
 149                         dup2(cmd->out, 1);
 150                         close(cmd->out);
 151                 }
 152
 153                 if (cmd->dir && chdir(cmd->dir))
 154                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 155                             cmd->dir);
 156                 if (cmd->env) {
 157                         for (; *cmd->env; cmd->env++) {
 158                                 if (strchr(*cmd->env, '='))
 159                                         putenv((char *)*cmd->env);
 160                                 else
 161                                         unsetenv(*cmd->env);
 162                         }
 163                 }
 164                 if (cmd->preexec_cb)
 165                         cmd->preexec_cb();
 166                 if (cmd->git_cmd) {
 167                         execv_git_cmd(cmd->argv);
 168                 } else if (cmd->use_shell) {
 169                         execv_shell_cmd(cmd->argv);
 170                 } else {
 171                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 172                 }
 173                 trace_printf("trace: exec '%s' failed: %s\n", cmd->argv[0],
 174                                 strerror(errno));
 175                 exit(127);
 176         }
 177         if (cmd->pid < 0)
 178                 error("cannot fork() for %s: %s", cmd->argv[0],
 179                         strerror(failed_errno = errno));
 180 #else
 181 {
 182         int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
 183         const char **sargv = cmd->argv;
 184         char **env = environ;
 185
 186         if (cmd->no_stdin) {
 187                 s0 = dup(0);
 188                 dup_devnull(0);
 189         } else if (need_in) {
 190                 s0 = dup(0);
 191                 dup2(fdin[0], 0);
 192         } else if (cmd->in) {
 193                 s0 = dup(0);
 194                 dup2(cmd->in, 0);
 195         }
 196
 197         if (cmd->no_stderr) {
 198                 s2 = dup(2);
 199                 dup_devnull(2);
 200         } else if (need_err) {
 201                 s2 = dup(2);
 202                 dup2(fderr[1], 2);
 203         }
 204
 205         if (cmd->no_stdout) {
 206                 s1 = dup(1);
 207                 dup_devnull(1);
 208         } else if (cmd->stdout_to_stderr) {
 209                 s1 = dup(1);
 210                 dup2(2, 1);
 211         } else if (need_out) {
 212                 s1 = dup(1);
 213                 dup2(fdout[1], 1);
 214         } else if (cmd->out > 1) {
 215                 s1 = dup(1);
 216                 dup2(cmd->out, 1);
 217         }
 218
 219         if (cmd->dir)
 220                 die("chdir in start_command() not implemented");
 221         if (cmd->env)
 222                 env = make_augmented_environ(cmd->env);
 223
 224         if (cmd->git_cmd) {
 225                 cmd->argv = prepare_git_cmd(cmd->argv);
 226         } else if (cmd->use_shell) {
 227                 cmd->argv = prepare_shell_cmd(cmd->argv);
 228         }
 229
 230         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
 231         failed_errno = errno;
 232         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 233                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 234
 235         if (cmd->env)
 236                 free_environ(env);
 237         if (cmd->git_cmd)
 238                 free(cmd->argv);
 239
 240         cmd->argv = sargv;
 241         if (s0 >= 0)
 242                 dup2(s0, 0), close(s0);
 243         if (s1 >= 0)
 244                 dup2(s1, 1), close(s1);
 245         if (s2 >= 0)
 246                 dup2(s2, 2), close(s2);
 247 }
 248 #endif
 249
 250         if (cmd->pid < 0) {
 251                 if (need_in)
 252                         close_pair(fdin);
 253                 else if (cmd->in)
 254                         close(cmd->in);
 255                 if (need_out)
 256                         close_pair(fdout);
 257                 else if (cmd->out)
 258                         close(cmd->out);
 259                 if (need_err)
 260                         close_pair(fderr);
 261                 errno = failed_errno;
 262                 return -1;
 263         }
 264
 265         if (need_in)
 266                 close(fdin[0]);
 267         else if (cmd->in)
 268                 close(cmd->in);
 269
 270         if (need_out)
 271                 close(fdout[1]);
 272         else if (cmd->out)
 273                 close(cmd->out);
 274
 275         if (need_err)
 276                 close(fderr[1]);
 277
 278         return 0;
 279 }
 280
 281 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 282 {
 283         int status, code = -1;
 284         pid_t waiting;
 285         int failed_errno = 0;
 286
 287         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 288                 ;       /* nothing */
 289
 290         if (waiting < 0) {
 291                 failed_errno = errno;
 292                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 293         } else if (waiting != pid) {
 294                 error("waitpid is confused (%s)", argv0);
 295         } else if (WIFSIGNALED(status)) {
 296                 code = WTERMSIG(status);
 297                 error("%s died of signal %d", argv0, code);
 298                 /*
 299                  * This return value is chosen so that code & 0xff
 300                  * mimics the exit code that a POSIX shell would report for
 301                  * a program that died from this signal.
 302                  */
 303                 code -= 128;
 304         } else if (WIFEXITED(status)) {
 305                 code = WEXITSTATUS(status);
 306                 /*
 307                  * Convert special exit code when execvp failed.
 308                  */
 309                 if (code == 127) {
 310                         code = -1;
 311                         failed_errno = ENOENT;
 312                         if (!silent_exec_failure)
 313                                 error("cannot run %s: %s", argv0,
 314                                         strerror(ENOENT));
 315                 }
 316         } else {
 317                 error("waitpid is confused (%s)", argv0);
 318         }
 319         errno = failed_errno;
 320         return code;
 321 }
 322
 323 int finish_command(struct child_process *cmd)
 324 {
 325         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 326 }
 327
 328 int run_command(struct child_process *cmd)
 329 {
 330         int code = start_command(cmd);
 331         if (code)
 332                 return code;
 333         return finish_command(cmd);
 334 }
 335
 336 static void prepare_run_command_v_opt(struct child_process *cmd,
 337                                       const char **argv,
 338                                       int opt)
 339 {
 340         memset(cmd, 0, sizeof(*cmd));
 341         cmd->argv = argv;
 342         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 343         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 344         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 345         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 346         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 347 }
 348
 349 int run_command_v_opt(const char **argv, int opt)
 350 {
 351         struct child_process cmd;
 352         prepare_run_command_v_opt(&cmd, argv, opt);
 353         return run_command(&cmd);
 354 }
 355
 356 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 357 {
 358         struct child_process cmd;
 359         prepare_run_command_v_opt(&cmd, argv, opt);
 360         cmd.dir = dir;
 361         cmd.env = env;
 362         return run_command(&cmd);
 363 }
 364
 365 #ifdef WIN32
 366 static unsigned __stdcall run_thread(void *data)
 367 {
 368         struct async *async = data;
 369         return async->proc(async->fd_for_proc, async->data);
 370 }
 371 #endif
 372
 373 int start_async(struct async *async)
 374 {
 375         int pipe_out[2];
 376
 377         if (pipe(pipe_out) < 0)
 378                 return error("cannot create pipe: %s", strerror(errno));
 379         async->out = pipe_out[0];
 380
 381 #ifndef WIN32
 382         /* Flush stdio before fork() to avoid cloning buffers */
 383         fflush(NULL);
 384
 385         async->pid = fork();
 386         if (async->pid < 0) {
 387                 error("fork (async) failed: %s", strerror(errno));
 388                 close_pair(pipe_out);
 389                 return -1;
 390         }
 391         if (!async->pid) {
 392                 close(pipe_out[0]);
 393                 exit(!!async->proc(pipe_out[1], async->data));
 394         }
 395         close(pipe_out[1]);
 396 #else
 397         async->fd_for_proc = pipe_out[1];
 398         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 399         if (!async->tid) {
 400                 error("cannot create thread: %s", strerror(errno));
 401                 close_pair(pipe_out);
 402                 return -1;
 403         }
 404 #endif
 405         return 0;
 406 }
 407
 408 int finish_async(struct async *async)
 409 {
 410 #ifndef WIN32
 411         int ret = wait_or_whine(async->pid, "child process", 0);
 412 #else
 413         DWORD ret = 0;
 414         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 415                 ret = error("waiting for thread failed: %lu", GetLastError());
 416         else if (!GetExitCodeThread(async->tid, &ret))
 417                 ret = error("cannot get thread exit code: %lu", GetLastError());
 418         CloseHandle(async->tid);
 419 #endif
 420         return ret;
 421 }
 422
 423 int run_hook(const char *index_file, const char *name, ...)
 424 {
 425         struct child_process hook;
 426         const char **argv = NULL, *env[2];
 427         char index[PATH_MAX];
 428         va_list args;
 429         int ret;
 430         size_t i = 0, alloc = 0;
 431
 432         if (access(git_path("hooks/%s", name), X_OK) < 0)
 433                 return 0;
 434
 435         va_start(args, name);
 436         ALLOC_GROW(argv, i + 1, alloc);
 437         argv[i++] = git_path("hooks/%s", name);
 438         while (argv[i-1]) {
 439                 ALLOC_GROW(argv, i + 1, alloc);
 440                 argv[i++] = va_arg(args, const char *);
 441         }
 442         va_end(args);
 443
 444         memset(&hook, 0, sizeof(hook));
 445         hook.argv = argv;
 446         hook.no_stdin = 1;
 447         hook.stdout_to_stderr = 1;
 448         if (index_file) {
 449                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 450                 env[0] = index;
 451                 env[1] = NULL;
 452                 hook.env = env;
 453         }
 454
 455         ret = run_command(&hook);
 456         free(argv);
 457         return ret;
 458 }