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("exec %s: cd to %s failed (%s)", cmd->argv[0],
 105                             cmd->dir, strerror(errno));
 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                 return code == 127 ? -ERR_RUN_COMMAND_EXEC : code;
 245         }
 246 }
 247
 248 int finish_command(struct child_process *cmd)
 249 {
 250         return wait_or_whine(cmd->pid);
 251 }
 252
 253 int run_command(struct child_process *cmd)
 254 {
 255         int code = start_command(cmd);
 256         if (code)
 257                 return code;
 258         return finish_command(cmd);
 259 }
 260
 261 static void prepare_run_command_v_opt(struct child_process *cmd,
 262                                       const char **argv,
 263                                       int opt)
 264 {
 265         memset(cmd, 0, sizeof(*cmd));
 266         cmd->argv = argv;
 267         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 268         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 269         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 270 }
 271
 272 int run_command_v_opt(const char **argv, int opt)
 273 {
 274         struct child_process cmd;
 275         prepare_run_command_v_opt(&cmd, argv, opt);
 276         return run_command(&cmd);
 277 }
 278
 279 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 280 {
 281         struct child_process cmd;
 282         prepare_run_command_v_opt(&cmd, argv, opt);
 283         cmd.dir = dir;
 284         cmd.env = env;
 285         return run_command(&cmd);
 286 }
 287
 288 #ifdef __MINGW32__
 289 static __stdcall unsigned run_thread(void *data)
 290 {
 291         struct async *async = data;
 292         return async->proc(async->fd_for_proc, async->data);
 293 }
 294 #endif
 295
 296 int start_async(struct async *async)
 297 {
 298         int pipe_out[2];
 299
 300         if (pipe(pipe_out) < 0)
 301                 return error("cannot create pipe: %s", strerror(errno));
 302         async->out = pipe_out[0];
 303
 304 #ifndef __MINGW32__
 305         /* Flush stdio before fork() to avoid cloning buffers */
 306         fflush(NULL);
 307
 308         async->pid = fork();
 309         if (async->pid < 0) {
 310                 error("fork (async) failed: %s", strerror(errno));
 311                 close_pair(pipe_out);
 312                 return -1;
 313         }
 314         if (!async->pid) {
 315                 close(pipe_out[0]);
 316                 exit(!!async->proc(pipe_out[1], async->data));
 317         }
 318         close(pipe_out[1]);
 319 #else
 320         async->fd_for_proc = pipe_out[1];
 321         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 322         if (!async->tid) {
 323                 error("cannot create thread: %s", strerror(errno));
 324                 close_pair(pipe_out);
 325                 return -1;
 326         }
 327 #endif
 328         return 0;
 329 }
 330
 331 int finish_async(struct async *async)
 332 {
 333 #ifndef __MINGW32__
 334         int ret = 0;
 335
 336         if (wait_or_whine(async->pid))
 337                 ret = error("waitpid (async) failed");
 338 #else
 339         DWORD ret = 0;
 340         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 341                 ret = error("waiting for thread failed: %lu", GetLastError());
 342         else if (!GetExitCodeThread(async->tid, &ret))
 343                 ret = error("cannot get thread exit code: %lu", GetLastError());
 344         CloseHandle(async->tid);
 345 #endif
 346         return ret;
 347 }
 348
 349 int run_hook(const char *index_file, const char *name, ...)
 350 {
 351         struct child_process hook;
 352         const char **argv = NULL, *env[2];
 353         char index[PATH_MAX];
 354         va_list args;
 355         int ret;
 356         size_t i = 0, alloc = 0;
 357
 358         if (access(git_path("hooks/%s", name), X_OK) < 0)
 359                 return 0;
 360
 361         va_start(args, name);
 362         ALLOC_GROW(argv, i + 1, alloc);
 363         argv[i++] = git_path("hooks/%s", name);
 364         while (argv[i-1]) {
 365                 ALLOC_GROW(argv, i + 1, alloc);
 366                 argv[i++] = va_arg(args, const char *);
 367         }
 368         va_end(args);
 369
 370         memset(&hook, 0, sizeof(hook));
 371         hook.argv = argv;
 372         hook.no_stdin = 1;
 373         hook.stdout_to_stderr = 1;
 374         if (index_file) {
 375                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 376                 env[0] = index;
 377                 env[1] = NULL;
 378                 hook.env = env;
 379         }
 380
 381         ret = start_command(&hook);
 382         free(argv);
 383         if (ret) {
 384                 warning("Could not spawn %s", argv[0]);
 385                 return ret;
 386         }
 387         ret = finish_command(&hook);
 388         if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
 389                 warning("%s exited due to uncaught signal", argv[0]);
 390
 391         return ret;
 392 }