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