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