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 static const char **prepare_shell_cmd(const char **argv)
  19 {
  20         int argc, nargc = 0;
  21         const char **nargv;
  22
  23         for (argc = 0; argv[argc]; argc++)
  24                 ; /* just counting */
  25         /* +1 for NULL, +3 for "sh -c" plus extra $0 */
  26         nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
  27
  28         if (argc < 1)
  29                 die("BUG: shell command is empty");
  30
  31         if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
  32                 nargv[nargc++] = "sh";
  33                 nargv[nargc++] = "-c";
  34
  35                 if (argc < 2)
  36                         nargv[nargc++] = argv[0];
  37                 else {
  38                         struct strbuf arg0 = STRBUF_INIT;
  39                         strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
  40                         nargv[nargc++] = strbuf_detach(&arg0, NULL);
  41                 }
  42         }
  43
  44         for (argc = 0; argv[argc]; argc++)
  45                 nargv[nargc++] = argv[argc];
  46         nargv[nargc] = NULL;
  47
  48         return nargv;
  49 }
  50
  51 #ifndef WIN32
  52 static int execv_shell_cmd(const char **argv)
  53 {
  54         const char **nargv = prepare_shell_cmd(argv);
  55         trace_argv_printf(nargv, "trace: exec:");
  56         execvp(nargv[0], (char **)nargv);
  57         free(nargv);
  58         return -1;
  59 }
  60 #endif
  61
  62 int start_command(struct child_process *cmd)
  63 {
  64         int need_in, need_out, need_err;
  65         int fdin[2], fdout[2], fderr[2];
  66         int failed_errno = failed_errno;
  67
  68         /*
  69          * In case of errors we must keep the promise to close FDs
  70          * that have been passed in via ->in and ->out.
  71          */
  72
  73         need_in = !cmd->no_stdin && cmd->in < 0;
  74         if (need_in) {
  75                 if (pipe(fdin) < 0) {
  76                         failed_errno = errno;
  77                         if (cmd->out > 0)
  78                                 close(cmd->out);
  79                         goto fail_pipe;
  80                 }
  81                 cmd->in = fdin[1];
  82         }
  83
  84         need_out = !cmd->no_stdout
  85                 && !cmd->stdout_to_stderr
  86                 && cmd->out < 0;
  87         if (need_out) {
  88                 if (pipe(fdout) < 0) {
  89                         failed_errno = errno;
  90                         if (need_in)
  91                                 close_pair(fdin);
  92                         else if (cmd->in)
  93                                 close(cmd->in);
  94                         goto fail_pipe;
  95                 }
  96                 cmd->out = fdout[0];
  97         }
  98
  99         need_err = !cmd->no_stderr && cmd->err < 0;
 100         if (need_err) {
 101                 if (pipe(fderr) < 0) {
 102                         failed_errno = errno;
 103                         if (need_in)
 104                                 close_pair(fdin);
 105                         else if (cmd->in)
 106                                 close(cmd->in);
 107                         if (need_out)
 108                                 close_pair(fdout);
 109                         else if (cmd->out)
 110                                 close(cmd->out);
 111 fail_pipe:
 112                         error("cannot create pipe for %s: %s",
 113                                 cmd->argv[0], strerror(failed_errno));
 114                         errno = failed_errno;
 115                         return -1;
 116                 }
 117                 cmd->err = fderr[0];
 118         }
 119
 120         trace_argv_printf(cmd->argv, "trace: run_command:");
 121
 122 #ifndef WIN32
 123         fflush(NULL);
 124         cmd->pid = fork();
 125         if (!cmd->pid) {
 126                 if (cmd->no_stdin)
 127                         dup_devnull(0);
 128                 else if (need_in) {
 129                         dup2(fdin[0], 0);
 130                         close_pair(fdin);
 131                 } else if (cmd->in) {
 132                         dup2(cmd->in, 0);
 133                         close(cmd->in);
 134                 }
 135
 136                 if (cmd->no_stderr)
 137                         dup_devnull(2);
 138                 else if (need_err) {
 139                         dup2(fderr[1], 2);
 140                         close_pair(fderr);
 141                 }
 142
 143                 if (cmd->no_stdout)
 144                         dup_devnull(1);
 145                 else if (cmd->stdout_to_stderr)
 146                         dup2(2, 1);
 147                 else if (need_out) {
 148                         dup2(fdout[1], 1);
 149                         close_pair(fdout);
 150                 } else if (cmd->out > 1) {
 151                         dup2(cmd->out, 1);
 152                         close(cmd->out);
 153                 }
 154
 155                 if (cmd->dir && chdir(cmd->dir))
 156                         die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
 157                             cmd->dir);
 158                 if (cmd->env) {
 159                         for (; *cmd->env; cmd->env++) {
 160                                 if (strchr(*cmd->env, '='))
 161                                         putenv((char *)*cmd->env);
 162                                 else
 163                                         unsetenv(*cmd->env);
 164                         }
 165                 }
 166                 if (cmd->preexec_cb)
 167                         cmd->preexec_cb();
 168                 if (cmd->git_cmd) {
 169                         execv_git_cmd(cmd->argv);
 170                 } else if (cmd->use_shell) {
 171                         execv_shell_cmd(cmd->argv);
 172                 } else {
 173                         execvp(cmd->argv[0], (char *const*) cmd->argv);
 174                 }
 175                 trace_printf("trace: exec '%s' failed: %s\n", cmd->argv[0],
 176                                 strerror(errno));
 177                 exit(127);
 178         }
 179         if (cmd->pid < 0)
 180                 error("cannot fork() for %s: %s", cmd->argv[0],
 181                         strerror(failed_errno = errno));
 182 #else
 183 {
 184         int s0 = -1, s1 = -1, s2 = -1;  /* backups of stdin, stdout, stderr */
 185         const char **sargv = cmd->argv;
 186         char **env = environ;
 187
 188         if (cmd->no_stdin) {
 189                 s0 = dup(0);
 190                 dup_devnull(0);
 191         } else if (need_in) {
 192                 s0 = dup(0);
 193                 dup2(fdin[0], 0);
 194         } else if (cmd->in) {
 195                 s0 = dup(0);
 196                 dup2(cmd->in, 0);
 197         }
 198
 199         if (cmd->no_stderr) {
 200                 s2 = dup(2);
 201                 dup_devnull(2);
 202         } else if (need_err) {
 203                 s2 = dup(2);
 204                 dup2(fderr[1], 2);
 205         }
 206
 207         if (cmd->no_stdout) {
 208                 s1 = dup(1);
 209                 dup_devnull(1);
 210         } else if (cmd->stdout_to_stderr) {
 211                 s1 = dup(1);
 212                 dup2(2, 1);
 213         } else if (need_out) {
 214                 s1 = dup(1);
 215                 dup2(fdout[1], 1);
 216         } else if (cmd->out > 1) {
 217                 s1 = dup(1);
 218                 dup2(cmd->out, 1);
 219         }
 220
 221         if (cmd->dir)
 222                 die("chdir in start_command() not implemented");
 223         if (cmd->env)
 224                 env = make_augmented_environ(cmd->env);
 225
 226         if (cmd->git_cmd) {
 227                 cmd->argv = prepare_git_cmd(cmd->argv);
 228         } else if (cmd->use_shell) {
 229                 cmd->argv = prepare_shell_cmd(cmd->argv);
 230         }
 231
 232         cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
 233         failed_errno = errno;
 234         if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
 235                 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
 236
 237         if (cmd->env)
 238                 free_environ(env);
 239         if (cmd->git_cmd)
 240                 free(cmd->argv);
 241
 242         cmd->argv = sargv;
 243         if (s0 >= 0)
 244                 dup2(s0, 0), close(s0);
 245         if (s1 >= 0)
 246                 dup2(s1, 1), close(s1);
 247         if (s2 >= 0)
 248                 dup2(s2, 2), close(s2);
 249 }
 250 #endif
 251
 252         if (cmd->pid < 0) {
 253                 if (need_in)
 254                         close_pair(fdin);
 255                 else if (cmd->in)
 256                         close(cmd->in);
 257                 if (need_out)
 258                         close_pair(fdout);
 259                 else if (cmd->out)
 260                         close(cmd->out);
 261                 if (need_err)
 262                         close_pair(fderr);
 263                 errno = failed_errno;
 264                 return -1;
 265         }
 266
 267         if (need_in)
 268                 close(fdin[0]);
 269         else if (cmd->in)
 270                 close(cmd->in);
 271
 272         if (need_out)
 273                 close(fdout[1]);
 274         else if (cmd->out)
 275                 close(cmd->out);
 276
 277         if (need_err)
 278                 close(fderr[1]);
 279
 280         return 0;
 281 }
 282
 283 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
 284 {
 285         int status, code = -1;
 286         pid_t waiting;
 287         int failed_errno = 0;
 288
 289         while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
 290                 ;       /* nothing */
 291
 292         if (waiting < 0) {
 293                 failed_errno = errno;
 294                 error("waitpid for %s failed: %s", argv0, strerror(errno));
 295         } else if (waiting != pid) {
 296                 error("waitpid is confused (%s)", argv0);
 297         } else if (WIFSIGNALED(status)) {
 298                 code = WTERMSIG(status);
 299                 error("%s died of signal %d", argv0, code);
 300                 /*
 301                  * This return value is chosen so that code & 0xff
 302                  * mimics the exit code that a POSIX shell would report for
 303                  * a program that died from this signal.
 304                  */
 305                 code -= 128;
 306         } else if (WIFEXITED(status)) {
 307                 code = WEXITSTATUS(status);
 308                 /*
 309                  * Convert special exit code when execvp failed.
 310                  */
 311                 if (code == 127) {
 312                         code = -1;
 313                         failed_errno = ENOENT;
 314                         if (!silent_exec_failure)
 315                                 error("cannot run %s: %s", argv0,
 316                                         strerror(ENOENT));
 317                 }
 318         } else {
 319                 error("waitpid is confused (%s)", argv0);
 320         }
 321         errno = failed_errno;
 322         return code;
 323 }
 324
 325 int finish_command(struct child_process *cmd)
 326 {
 327         return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
 328 }
 329
 330 int run_command(struct child_process *cmd)
 331 {
 332         int code = start_command(cmd);
 333         if (code)
 334                 return code;
 335         return finish_command(cmd);
 336 }
 337
 338 static void prepare_run_command_v_opt(struct child_process *cmd,
 339                                       const char **argv,
 340                                       int opt)
 341 {
 342         memset(cmd, 0, sizeof(*cmd));
 343         cmd->argv = argv;
 344         cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
 345         cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
 346         cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 347         cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 348         cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 349 }
 350
 351 int run_command_v_opt(const char **argv, int opt)
 352 {
 353         struct child_process cmd;
 354         prepare_run_command_v_opt(&cmd, argv, opt);
 355         return run_command(&cmd);
 356 }
 357
 358 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
 359 {
 360         struct child_process cmd;
 361         prepare_run_command_v_opt(&cmd, argv, opt);
 362         cmd.dir = dir;
 363         cmd.env = env;
 364         return run_command(&cmd);
 365 }
 366
 367 #ifdef WIN32
 368 static unsigned __stdcall run_thread(void *data)
 369 {
 370         struct async *async = data;
 371         return async->proc(async->fd_for_proc, async->data);
 372 }
 373 #endif
 374
 375 int start_async(struct async *async)
 376 {
 377         int pipe_out[2];
 378
 379         if (pipe(pipe_out) < 0)
 380                 return error("cannot create pipe: %s", strerror(errno));
 381         async->out = pipe_out[0];
 382
 383 #ifndef WIN32
 384         /* Flush stdio before fork() to avoid cloning buffers */
 385         fflush(NULL);
 386
 387         async->pid = fork();
 388         if (async->pid < 0) {
 389                 error("fork (async) failed: %s", strerror(errno));
 390                 close_pair(pipe_out);
 391                 return -1;
 392         }
 393         if (!async->pid) {
 394                 close(pipe_out[0]);
 395                 exit(!!async->proc(pipe_out[1], async->data));
 396         }
 397         close(pipe_out[1]);
 398 #else
 399         async->fd_for_proc = pipe_out[1];
 400         async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
 401         if (!async->tid) {
 402                 error("cannot create thread: %s", strerror(errno));
 403                 close_pair(pipe_out);
 404                 return -1;
 405         }
 406 #endif
 407         return 0;
 408 }
 409
 410 int finish_async(struct async *async)
 411 {
 412 #ifndef WIN32
 413         int ret = wait_or_whine(async->pid, "child process", 0);
 414 #else
 415         DWORD ret = 0;
 416         if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
 417                 ret = error("waiting for thread failed: %lu", GetLastError());
 418         else if (!GetExitCodeThread(async->tid, &ret))
 419                 ret = error("cannot get thread exit code: %lu", GetLastError());
 420         CloseHandle(async->tid);
 421 #endif
 422         return ret;
 423 }
 424
 425 int run_hook(const char *index_file, const char *name, ...)
 426 {
 427         struct child_process hook;
 428         const char **argv = NULL, *env[2];
 429         char index[PATH_MAX];
 430         va_list args;
 431         int ret;
 432         size_t i = 0, alloc = 0;
 433
 434         if (access(git_path("hooks/%s", name), X_OK) < 0)
 435                 return 0;
 436
 437         va_start(args, name);
 438         ALLOC_GROW(argv, i + 1, alloc);
 439         argv[i++] = git_path("hooks/%s", name);
 440         while (argv[i-1]) {
 441                 ALLOC_GROW(argv, i + 1, alloc);
 442                 argv[i++] = va_arg(args, const char *);
 443         }
 444         va_end(args);
 445
 446         memset(&hook, 0, sizeof(hook));
 447         hook.argv = argv;
 448         hook.no_stdin = 1;
 449         hook.stdout_to_stderr = 1;
 450         if (index_file) {
 451                 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
 452                 env[0] = index;
 453                 env[1] = NULL;
 454                 hook.env = env;
 455         }
 456
 457         ret = run_command(&hook);
 458         free(argv);
 459         return ret;
 460 }