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 WIN32
  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 {
 127         int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
 128         const char **sargv = cmd->argv;
 129         char **env = environ;
 130
 131         if (cmd->no_stdin) {
 132                 s0 = dup(0);
 133                 dup_devnull(0);
 134         } else if (need_in) {
 135                 s0 = dup(0);
 136                 dup2(fdin[0], 0);
 137         } else if (cmd->in) {
 138                 s0 = dup(0);
 139                 dup2(cmd->in, 0);
 140         }
 141
 142         if (cmd->no_stderr) {
 143                 s2 = dup(2);
 144                 dup_devnull(2);
 145         } else if (need_err) {
 146                 s2 = dup(2);
 147                 dup2(fderr[1], 2);
 148         }
 149
 150         if (cmd->no_stdout) {
 151                 s1 = dup(1);
 152                 dup_devnull(1);
 153         } else if (cmd->stdout_to_stderr) {
 154                 s1 = dup(1);
 155                 dup2(2, 1);
 156         } else if (need_out) {
 157                 s1 = dup(1);
 158                 dup2(fdout[1], 1);
 159         } else if (cmd->out > 1) {
 160                 s1 = dup(1);
 161                 dup2(cmd->out, 1);
 162         }
 163
 164         if (cmd->dir)
 165                 die("chdir in start_command() not implemented");
 166         if (cmd->env) {
 167                 env = copy_environ();
 168                 for (; *cmd->env; cmd->env++)
 169                         env = env_setenv(env, *cmd->env);
 170         }
 171
 172         if (cmd->git_cmd) {
 173                 cmd->argv = prepare_git_cmd(cmd->argv);
 174         }
 175
 176         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
 177
 178         if (cmd->env)
 179                 free_environ(env);
 180         if (cmd->git_cmd)
 181                 free(cmd->argv);
 182
 183         cmd->argv = sargv;
 184         if (s0 >= 0)
 185                 dup2(s0, 0), close(s0);
 186         if (s1 >= 0)
 187                 dup2(s1, 1), close(s1);
 188         if (s2 >= 0)
 189                 dup2(s2, 2), close(s2);
 190 }
 191 #endif
 192
 193         if (cmd->pid < 0) {
 194                 int err = errno;
 195                 if (need_in)
 196                         close_pair(fdin);
 197                 else if (cmd->in)
 198                         close(cmd->in);
 199                 if (need_out)
 200                         close_pair(fdout);
 201                 else if (cmd->out)
 202                         close(cmd->out);
 203                 if (need_err)
 204                         close_pair(fderr);
 205                 return err == ENOENT ?
 206                         -ERR_RUN_COMMAND_EXEC :
 207                         -ERR_RUN_COMMAND_FORK;
 208         }
 209
 210         if (need_in)
 211                 close(fdin[0]);
 212         else if (cmd->in)
 213                 close(cmd->in);
 214
 215         if (need_out)
 216                 close(fdout[1]);
 217         else if (cmd->out)
 218                 close(cmd->out);
 219
 220         if (need_err)
 221                 close(fderr[1]);
 222
 223         return 0;
 224 }
 225
 226 static int wait_or_whine(pid_t pid)
 227 {
 228         for (;;) {
 229                 int status, code;
 230                 pid_t waiting = waitpid(pid, &status, 0);
 231
 232                 if (waiting < 0) {
 233                         if (errno == EINTR)
 234                                 continue;
 235                         error("waitpid failed (%s)", strerror(errno));
 236                         return -ERR_RUN_COMMAND_WAITPID;
 237                 }
 238                 if (waiting != pid)
 239                         return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
 240                 if (WIFSIGNALED(status))
 241                         return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
 242
 243                 if (!WIFEXITED(status))
 244                         return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
 245                 code = WEXITSTATUS(status);
 246                 switch (code) {
 247                 case 127:
 248                         return -ERR_RUN_COMMAND_EXEC;
 249                 case 0:
 250                         return 0;
 251                 default:
 252                         return -code;
 253                 }
 254         }
 255 }
 256
 257 int finish_command(struct child_process *cmd)
 258 {
 259         return wait_or_whine(cmd->pid);
 260 }
 261
 262 int run_command(struct child_process *cmd)
 263 {
 264         int code = start_command(cmd);
 265         if (code)
 266                 return code;
 267         return finish_command(cmd);
 268 }
 269
 270 static void prepare_run_command_v_opt(struct child_process *cmd,
 271                                       const char **argv,
 272                                       int opt)
 273 {
 274         memset(cmd, 0, sizeof(*cmd));
 275         cmd->argv = argv;
 276         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 277         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 278         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 279 }
 280
 281 int run_command_v_opt(const char **argv, int opt)
 282 {
 283         struct child_process cmd;
 284         prepare_run_command_v_opt(&cmd, argv, opt);
 285         return run_command(&cmd);
 286 }
 287
 288 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 289 {
 290         struct child_process cmd;
 291         prepare_run_command_v_opt(&cmd, argv, opt);
 292         cmd.dir = dir;
 293         cmd.env = env;
 294         return run_command(&cmd);
 295 }
 296
 297 #ifdef WIN32
 298 static unsigned __stdcall run_thread(void *data)
 299 {
 300         struct async *async = data;
 301         return async->proc(async->fd_for_proc, async->data);
 302 }
 303 #endif
 304
 305 int start_async(struct async *async)
 306 {
 307         int pipe_out[2];
 308
 309         if (pipe(pipe_out) < 0)
 310                 return error("cannot create pipe: %s", strerror(errno));
 311         async->out = pipe_out[0];
 312
 313 #ifndef WIN32
 314         /* Flush stdio before fork() to avoid cloning buffers */
 315         fflush(NULL);
 316
 317         async->pid = fork();
 318         if (async->pid < 0) {
 319                 error("fork (async) failed: %s", strerror(errno));
 320                 close_pair(pipe_out);
 321                 return -1;
 322         }
 323         if (!async->pid) {
 324                 close(pipe_out[0]);
 325                 exit(!!async->proc(pipe_out[1], async->data));
 326         }
 327         close(pipe_out[1]);
 328 #else
 329         async->fd_for_proc = pipe_out[1];
 330         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 331         if (!async->tid) {
 332                 error("cannot create thread: %s", strerror(errno));
 333                 close_pair(pipe_out);
 334                 return -1;
 335         }
 336 #endif
 337         return 0;
 338 }
 339
 340 int finish_async(struct async *async)
 341 {
 342 #ifndef WIN32
 343         int ret = 0;
 344
 345         if (wait_or_whine(async->pid))
 346                 ret = error("waitpid (async) failed");
 347 #else
 348         DWORD ret = 0;
 349         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 350                 ret = error("waiting for thread failed: %lu", GetLastError());
 351         else if (!GetExitCodeThread(async->tid, &ret))
 352                 ret = error("cannot get thread exit code: %lu", GetLastError());
 353         CloseHandle(async->tid);
 354 #endif
 355         return ret;
 356 }
 357
 358 int run_hook(const char *index_file, const char *name, ...)
 359 {
 360         struct child_process hook;
 361         const char **argv = NULL, *env[2];
 362         char index[PATH_MAX];
 363         va_list args;
 364         int ret;
 365         size_t i = 0, alloc = 0;
 366
 367         if (access(git_path("hooks/%s", name), X_OK) < 0)
 368                 return 0;
 369
 370         va_start(args, name);
 371         ALLOC_GROW(argv, i + 1, alloc);
 372         argv[i++] = git_path("hooks/%s", name);
 373         while (argv[i-1]) {
 374                 ALLOC_GROW(argv, i + 1, alloc);
 375                 argv[i++] = va_arg(args, const char *);
 376         }
 377         va_end(args);
 378
 379         memset(&hook, 0, sizeof(hook));
 380         hook.argv = argv;
 381         hook.no_stdin = 1;
 382         hook.stdout_to_stderr = 1;
 383         if (index_file) {
 384                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 385                 env[0] = index;
 386                 env[1] = NULL;
 387                 hook.env = env;
 388         }
 389
 390         ret = start_command(&hook);
 391         free(argv);
 392         if (ret) {
 393                 warning("Could not spawn %s", argv[0]);
 394                 return ret;
 395         }
 396         ret = finish_command(&hook);
 397         if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
 398                 warning("%s exited due to uncaught signal", argv[0]);
 399
 400         return ret;
 401 }