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;
  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 __MINGW32__
  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("exec %s: cd to %s failed (%s)", cmd->argv[0],
 113                             cmd->dir, strerror(errno));
 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         int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
 138         const char **sargv = cmd->argv;
 139         char **env = environ;
 140
 141         if (cmd->no_stdin) {
 142                 s0 = dup(0);
 143                 dup_devnull(0);
 144         } else if (need_in) {
 145                 s0 = dup(0);
 146                 dup2(fdin[0], 0);
 147         } else if (cmd->in) {
 148                 s0 = dup(0);
 149                 dup2(cmd->in, 0);
 150         }
 151
 152         if (cmd->no_stderr) {
 153                 s2 = dup(2);
 154                 dup_devnull(2);
 155         } else if (need_err) {
 156                 s2 = dup(2);
 157                 dup2(fderr[1], 2);
 158         }
 159
 160         if (cmd->no_stdout) {
 161                 s1 = dup(1);
 162                 dup_devnull(1);
 163         } else if (cmd->stdout_to_stderr) {
 164                 s1 = dup(1);
 165                 dup2(2, 1);
 166         } else if (need_out) {
 167                 s1 = dup(1);
 168                 dup2(fdout[1], 1);
 169         } else if (cmd->out > 1) {
 170                 s1 = dup(1);
 171                 dup2(cmd->out, 1);
 172         }
 173
 174         if (cmd->dir)
 175                 die("chdir in start_command() not implemented");
 176         if (cmd->env) {
 177                 env = copy_environ();
 178                 for (; *cmd->env; cmd->env++)
 179                         env = env_setenv(env, *cmd->env);
 180         }
 181
 182         if (cmd->git_cmd) {
 183                 cmd->argv = prepare_git_cmd(cmd->argv);
 184         }
 185
 186         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
 187         failed_errno = errno;
 188         if (cmd->pid < 0 && errno != ENOENT)
 189                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 190
 191         if (cmd->env)
 192                 free_environ(env);
 193         if (cmd->git_cmd)
 194                 free(cmd->argv);
 195
 196         cmd->argv = sargv;
 197         if (s0 >= 0)
 198                 dup2(s0, 0), close(s0);
 199         if (s1 >= 0)
 200                 dup2(s1, 1), close(s1);
 201         if (s2 >= 0)
 202                 dup2(s2, 2), close(s2);
 203 #endif
 204
 205         if (cmd->pid < 0) {
 206                 if (need_in)
 207                         close_pair(fdin);
 208                 else if (cmd->in)
 209                         close(cmd->in);
 210                 if (need_out)
 211                         close_pair(fdout);
 212                 else if (cmd->out)
 213                         close(cmd->out);
 214                 if (need_err)
 215                         close_pair(fderr);
 216                 errno = failed_errno;
 217                 return -1;
 218         }
 219
 220         if (need_in)
 221                 close(fdin[0]);
 222         else if (cmd->in)
 223                 close(cmd->in);
 224
 225         if (need_out)
 226                 close(fdout[1]);
 227         else if (cmd->out)
 228                 close(cmd->out);
 229
 230         if (need_err)
 231                 close(fderr[1]);
 232
 233         return 0;
 234 }
 235
 236 static int wait_or_whine(pid_t pid, const char *argv0)
 237 {
 238         int status, code = -1;
 239         pid_t waiting;
 240         int failed_errno = 0;
 241
 242         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 243                 ;       /* nothing */
 244
 245         if (waiting < 0) {
 246                 failed_errno = errno;
 247                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 248         } else if (waiting != pid) {
 249                 error("waitpid is confused (%s)", argv0);
 250         } else if (WIFSIGNALED(status)) {
 251                 code = WTERMSIG(status);
 252                 error("%s died of signal %d", argv0, code);
 253                 /*
 254                  * This return value is chosen so that code & 0xff
 255                  * mimics the exit code that a POSIX shell would report for
 256                  * a program that died from this signal.
 257                  */
 258                 code -= 128;
 259         } else if (WIFEXITED(status)) {
 260                 code = WEXITSTATUS(status);
 261                 /*
 262                  * Convert special exit code when execvp failed.
 263                  */
 264                 if (code == 127) {
 265                         code = -1;
 266                         failed_errno = ENOENT;
 267                 }
 268         } else {
 269                 error("waitpid is confused (%s)", argv0);
 270         }
 271         errno = failed_errno;
 272         return code;
 273 }
 274
 275 int finish_command(struct child_process *cmd)
 276 {
 277         return wait_or_whine(cmd->pid, cmd->argv[0]);
 278 }
 279
 280 int run_command(struct child_process *cmd)
 281 {
 282         int code = start_command(cmd);
 283         if (code)
 284                 return code;
 285         return finish_command(cmd);
 286 }
 287
 288 static void prepare_run_command_v_opt(struct child_process *cmd,
 289                                       const char **argv,
 290                                       int opt)
 291 {
 292         memset(cmd, 0, sizeof(*cmd));
 293         cmd->argv = argv;
 294         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 295         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 296         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 297 }
 298
 299 int run_command_v_opt(const char **argv, int opt)
 300 {
 301         struct child_process cmd;
 302         prepare_run_command_v_opt(&cmd, argv, opt);
 303         return run_command(&cmd);
 304 }
 305
 306 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 307 {
 308         struct child_process cmd;
 309         prepare_run_command_v_opt(&cmd, argv, opt);
 310         cmd.dir = dir;
 311         cmd.env = env;
 312         return run_command(&cmd);
 313 }
 314
 315 #ifdef __MINGW32__
 316 static __stdcall unsigned run_thread(void *data)
 317 {
 318         struct async *async = data;
 319         return async->proc(async->fd_for_proc, async->data);
 320 }
 321 #endif
 322
 323 int start_async(struct async *async)
 324 {
 325         int pipe_out[2];
 326
 327         if (pipe(pipe_out) < 0)
 328                 return error("cannot create pipe: %s", strerror(errno));
 329         async->out = pipe_out[0];
 330
 331 #ifndef __MINGW32__
 332         /* Flush stdio before fork() to avoid cloning buffers */
 333         fflush(NULL);
 334
 335         async->pid = fork();
 336         if (async->pid < 0) {
 337                 error("fork (async) failed: %s", strerror(errno));
 338                 close_pair(pipe_out);
 339                 return -1;
 340         }
 341         if (!async->pid) {
 342                 close(pipe_out[0]);
 343                 exit(!!async->proc(pipe_out[1], async->data));
 344         }
 345         close(pipe_out[1]);
 346 #else
 347         async->fd_for_proc = pipe_out[1];
 348         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 349         if (!async->tid) {
 350                 error("cannot create thread: %s", strerror(errno));
 351                 close_pair(pipe_out);
 352                 return -1;
 353         }
 354 #endif
 355         return 0;
 356 }
 357
 358 int finish_async(struct async *async)
 359 {
 360 #ifndef __MINGW32__
 361         int ret = wait_or_whine(async->pid, "child process");
 362 #else
 363         DWORD ret = 0;
 364         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 365                 ret = error("waiting for thread failed: %lu", GetLastError());
 366         else if (!GetExitCodeThread(async->tid, &ret))
 367                 ret = error("cannot get thread exit code: %lu", GetLastError());
 368         CloseHandle(async->tid);
 369 #endif
 370         return ret;
 371 }
 372
 373 int run_hook(const char *index_file, const char *name, ...)
 374 {
 375         struct child_process hook;
 376         const char **argv = NULL, *env[2];
 377         char index[PATH_MAX];
 378         va_list args;
 379         int ret;
 380         size_t i = 0, alloc = 0;
 381
 382         if (access(git_path("hooks/%s", name), X_OK) < 0)
 383                 return 0;
 384
 385         va_start(args, name);
 386         ALLOC_GROW(argv, i + 1, alloc);
 387         argv[i++] = git_path("hooks/%s", name);
 388         while (argv[i-1]) {
 389                 ALLOC_GROW(argv, i + 1, alloc);
 390                 argv[i++] = va_arg(args, const char *);
 391         }
 392         va_end(args);
 393
 394         memset(&hook, 0, sizeof(hook));
 395         hook.argv = argv;
 396         hook.no_stdin = 1;
 397         hook.stdout_to_stderr = 1;
 398         if (index_file) {
 399                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 400                 env[0] = index;
 401                 env[1] = NULL;
 402                 hook.env = env;
 403         }
 404
 405         ret = run_command(&hook);
 406         free(argv);
 407         return ret;
 408 }