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
  23         /*
  24          * In case of errors we must keep the promise to close FDs
  25          * that have been passed in via ->in and ->out.
  26          */
  27
  28         need_in = !cmd->no_stdin && cmd->in < 0;
  29         if (need_in) {
  30                 if (pipe(fdin) < 0) {
  31                         if (cmd->out > 0)
  32                                 close(cmd->out);
  33                         return -ERR_RUN_COMMAND_PIPE;
  34                 }
  35                 cmd->in = fdin[1];
  36         }
  37
  38         need_out = !cmd->no_stdout
  39                 && !cmd->stdout_to_stderr
  40                 && cmd->out < 0;
  41         if (need_out) {
  42                 if (pipe(fdout) < 0) {
  43                         if (need_in)
  44                                 close_pair(fdin);
  45                         else if (cmd->in)
  46                                 close(cmd->in);
  47                         return -ERR_RUN_COMMAND_PIPE;
  48                 }
  49                 cmd->out = fdout[0];
  50         }
  51
  52         need_err = !cmd->no_stderr && cmd->err < 0;
  53         if (need_err) {
  54                 if (pipe(fderr) < 0) {
  55                         if (need_in)
  56                                 close_pair(fdin);
  57                         else if (cmd->in)
  58                                 close(cmd->in);
  59                         if (need_out)
  60                                 close_pair(fdout);
  61                         else if (cmd->out)
  62                                 close(cmd->out);
  63                         return -ERR_RUN_COMMAND_PIPE;
  64                 }
  65                 cmd->err = fderr[0];
  66         }
  67
  68         trace_argv_printf(cmd->argv, "trace: run_command:");
  69
  70 #ifndef __MINGW32__
  71         fflush(NULL);
  72         cmd->pid = fork();
  73         if (!cmd->pid) {
  74                 if (cmd->no_stdin)
  75                         dup_devnull(0);
  76                 else if (need_in) {
  77                         dup2(fdin[0], 0);
  78                         close_pair(fdin);
  79                 } else if (cmd->in) {
  80                         dup2(cmd->in, 0);
  81                         close(cmd->in);
  82                 }
  83
  84                 if (cmd->no_stderr)
  85                         dup_devnull(2);
  86                 else if (need_err) {
  87                         dup2(fderr[1], 2);
  88                         close_pair(fderr);
  89                 }
  90
  91                 if (cmd->no_stdout)
  92                         dup_devnull(1);
  93                 else if (cmd->stdout_to_stderr)
  94                         dup2(2, 1);
  95                 else if (need_out) {
  96                         dup2(fdout[1], 1);
  97                         close_pair(fdout);
  98                 } else if (cmd->out > 1) {
  99                         dup2(cmd->out, 1);
 100                         close(cmd->out);
 101                 }
 102
 103                 if (cmd->dir && chdir(cmd->dir))
 104                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 105                             cmd->dir);
 106                 if (cmd->env) {
 107                         for (; *cmd->env; cmd->env++) {
 108                                 if (strchr(*cmd->env, '='))
 109                                         putenv((char *)*cmd->env);
 110                                 else
 111                                         unsetenv(*cmd->env);
 112                         }
 113                 }
 114                 if (cmd->preexec_cb)
 115                         cmd->preexec_cb();
 116                 if (cmd->git_cmd) {
 117                         execv_git_cmd(cmd->argv);
 118                 } else {
 119                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 120                 }
 121                 trace_printf("trace: exec '%s' failed: %s\n", cmd->argv[0],
 122                                 strerror(errno));
 123                 exit(127);
 124         }
 125 #else
 126         int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
 127         const char **sargv = cmd->argv;
 128         char **env = environ;
 129
 130         if (cmd->no_stdin) {
 131                 s0 = dup(0);
 132                 dup_devnull(0);
 133         } else if (need_in) {
 134                 s0 = dup(0);
 135                 dup2(fdin[0], 0);
 136         } else if (cmd->in) {
 137                 s0 = dup(0);
 138                 dup2(cmd->in, 0);
 139         }
 140
 141         if (cmd->no_stderr) {
 142                 s2 = dup(2);
 143                 dup_devnull(2);
 144         } else if (need_err) {
 145                 s2 = dup(2);
 146                 dup2(fderr[1], 2);
 147         }
 148
 149         if (cmd->no_stdout) {
 150                 s1 = dup(1);
 151                 dup_devnull(1);
 152         } else if (cmd->stdout_to_stderr) {
 153                 s1 = dup(1);
 154                 dup2(2, 1);
 155         } else if (need_out) {
 156                 s1 = dup(1);
 157                 dup2(fdout[1], 1);
 158         } else if (cmd->out > 1) {
 159                 s1 = dup(1);
 160                 dup2(cmd->out, 1);
 161         }
 162
 163         if (cmd->dir)
 164                 die("chdir in start_command() not implemented");
 165         if (cmd->env) {
 166                 env = copy_environ();
 167                 for (; *cmd->env; cmd->env++)
 168                         env = env_setenv(env, *cmd->env);
 169         }
 170
 171         if (cmd->git_cmd) {
 172                 cmd->argv = prepare_git_cmd(cmd->argv);
 173         }
 174
 175         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
 176
 177         if (cmd->env)
 178                 free_environ(env);
 179         if (cmd->git_cmd)
 180                 free(cmd->argv);
 181
 182         cmd->argv = sargv;
 183         if (s0 >= 0)
 184                 dup2(s0, 0), close(s0);
 185         if (s1 >= 0)
 186                 dup2(s1, 1), close(s1);
 187         if (s2 >= 0)
 188                 dup2(s2, 2), close(s2);
 189 #endif
 190
 191         if (cmd->pid < 0) {
 192                 int err = errno;
 193                 if (need_in)
 194                         close_pair(fdin);
 195                 else if (cmd->in)
 196                         close(cmd->in);
 197                 if (need_out)
 198                         close_pair(fdout);
 199                 else if (cmd->out)
 200                         close(cmd->out);
 201                 if (need_err)
 202                         close_pair(fderr);
 203                 return err == ENOENT ?
 204                         -ERR_RUN_COMMAND_EXEC :
 205                         -ERR_RUN_COMMAND_FORK;
 206         }
 207
 208         if (need_in)
 209                 close(fdin[0]);
 210         else if (cmd->in)
 211                 close(cmd->in);
 212
 213         if (need_out)
 214                 close(fdout[1]);
 215         else if (cmd->out)
 216                 close(cmd->out);
 217
 218         if (need_err)
 219                 close(fderr[1]);
 220
 221         return 0;
 222 }
 223
 224 static int wait_or_whine(pid_t pid)
 225 {
 226         for (;;) {
 227                 int status, code;
 228                 pid_t waiting = waitpid(pid, &status, 0);
 229
 230                 if (waiting < 0) {
 231                         if (errno == EINTR)
 232                                 continue;
 233                         error("waitpid failed (%s)", strerror(errno));
 234                         return -ERR_RUN_COMMAND_WAITPID;
 235                 }
 236                 if (waiting != pid)
 237                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 238                 if (WIFSIGNALED(status))
 239                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 240
 241                 if (!WIFEXITED(status))
 242                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 243                 code = WEXITSTATUS(status);
 244                 switch (code) {
 245                 case 127:
 246                         return -ERR_RUN_COMMAND_EXEC;
 247                 case 0:
 248                         return 0;
 249                 default:
 250                         return -code;
 251                 }
 252         }
 253 }
 254
 255 int finish_command(struct child_process *cmd)
 256 {
 257         return wait_or_whine(cmd->pid);
 258 }
 259
 260 int run_command(struct child_process *cmd)
 261 {
 262         int code = start_command(cmd);
 263         if (code)
 264                 return code;
 265         return finish_command(cmd);
 266 }
 267
 268 static void prepare_run_command_v_opt(struct child_process *cmd,
 269                                       const char **argv,
 270                                       int opt)
 271 {
 272         memset(cmd, 0, sizeof(*cmd));
 273         cmd->argv = argv;
 274         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 275         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 276         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 277 }
 278
 279 int run_command_v_opt(const char **argv, int opt)
 280 {
 281         struct child_process cmd;
 282         prepare_run_command_v_opt(&cmd, argv, opt);
 283         return run_command(&cmd);
 284 }
 285
 286 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 287 {
 288         struct child_process cmd;
 289         prepare_run_command_v_opt(&cmd, argv, opt);
 290         cmd.dir = dir;
 291         cmd.env = env;
 292         return run_command(&cmd);
 293 }
 294
 295 #ifdef __MINGW32__
 296 static __stdcall unsigned run_thread(void *data)
 297 {
 298         struct async *async = data;
 299         return async->proc(async->fd_for_proc, async->data);
 300 }
 301 #endif
 302
 303 int start_async(struct async *async)
 304 {
 305         int pipe_out[2];
 306
 307         if (pipe(pipe_out) < 0)
 308                 return error("cannot create pipe: %s", strerror(errno));
 309         async->out = pipe_out[0];
 310
 311 #ifndef __MINGW32__
 312         /* Flush stdio before fork() to avoid cloning buffers */
 313         fflush(NULL);
 314
 315         async->pid = fork();
 316         if (async->pid < 0) {
 317                 error("fork (async) failed: %s", strerror(errno));
 318                 close_pair(pipe_out);
 319                 return -1;
 320         }
 321         if (!async->pid) {
 322                 close(pipe_out[0]);
 323                 exit(!!async->proc(pipe_out[1], async->data));
 324         }
 325         close(pipe_out[1]);
 326 #else
 327         async->fd_for_proc = pipe_out[1];
 328         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 329         if (!async->tid) {
 330                 error("cannot create thread: %s", strerror(errno));
 331                 close_pair(pipe_out);
 332                 return -1;
 333         }
 334 #endif
 335         return 0;
 336 }
 337
 338 int finish_async(struct async *async)
 339 {
 340 #ifndef __MINGW32__
 341         int ret = 0;
 342
 343         if (wait_or_whine(async->pid))
 344                 ret = error("waitpid (async) failed");
 345 #else
 346         DWORD ret = 0;
 347         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 348                 ret = error("waiting for thread failed: %lu", GetLastError());
 349         else if (!GetExitCodeThread(async->tid, &ret))
 350                 ret = error("cannot get thread exit code: %lu", GetLastError());
 351         CloseHandle(async->tid);
 352 #endif
 353         return ret;
 354 }
 355
 356 int run_hook(const char *index_file, const char *name, ...)
 357 {
 358         struct child_process hook;
 359         const char **argv = NULL, *env[2];
 360         char index[PATH_MAX];
 361         va_list args;
 362         int ret;
 363         size_t i = 0, alloc = 0;
 364
 365         if (access(git_path("hooks/%s", name), X_OK) < 0)
 366                 return 0;
 367
 368         va_start(args, name);
 369         ALLOC_GROW(argv, i + 1, alloc);
 370         argv[i++] = git_path("hooks/%s", name);
 371         while (argv[i-1]) {
 372                 ALLOC_GROW(argv, i + 1, alloc);
 373                 argv[i++] = va_arg(args, const char *);
 374         }
 375         va_end(args);
 376
 377         memset(&hook, 0, sizeof(hook));
 378         hook.argv = argv;
 379         hook.no_stdin = 1;
 380         hook.stdout_to_stderr = 1;
 381         if (index_file) {
 382                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 383                 env[0] = index;
 384                 env[1] = NULL;
 385                 hook.env = env;
 386         }
 387
 388         ret = start_command(&hook);
 389         free(argv);
 390         if (ret) {
 391                 warning("Could not spawn %s", argv[0]);
 392                 return ret;
 393         }
 394         ret = finish_command(&hook);
 395         if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
 396                 warning("%s exited due to uncaught signal", argv[0]);
 397
 398         return ret;
 399 }