start_command: report child process setup errors to the parent's stderr
[git/git.git] / 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 #ifndef WIN32
19 static int child_err = 2;
20
21 static NORETURN void die_child(const char *err, va_list params)
22 {
23 char msg[4096];
24 int len = vsnprintf(msg, sizeof(msg), err, params);
25 if (len > sizeof(msg))
26 len = sizeof(msg);
27
28 write(child_err, "fatal: ", 7);
29 write(child_err, msg, len);
30 write(child_err, "\n", 1);
31 exit(128);
32 }
33
34 static inline void set_cloexec(int fd)
35 {
36 int flags = fcntl(fd, F_GETFD);
37 if (flags >= 0)
38 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
39 }
40 #endif
41
42 int start_command(struct child_process *cmd)
43 {
44 int need_in, need_out, need_err;
45 int fdin[2], fdout[2], fderr[2];
46 int failed_errno = failed_errno;
47
48 /*
49 * In case of errors we must keep the promise to close FDs
50 * that have been passed in via ->in and ->out.
51 */
52
53 need_in = !cmd->no_stdin && cmd->in < 0;
54 if (need_in) {
55 if (pipe(fdin) < 0) {
56 failed_errno = errno;
57 if (cmd->out > 0)
58 close(cmd->out);
59 goto fail_pipe;
60 }
61 cmd->in = fdin[1];
62 }
63
64 need_out = !cmd->no_stdout
65 && !cmd->stdout_to_stderr
66 && cmd->out < 0;
67 if (need_out) {
68 if (pipe(fdout) < 0) {
69 failed_errno = errno;
70 if (need_in)
71 close_pair(fdin);
72 else if (cmd->in)
73 close(cmd->in);
74 goto fail_pipe;
75 }
76 cmd->out = fdout[0];
77 }
78
79 need_err = !cmd->no_stderr && cmd->err < 0;
80 if (need_err) {
81 if (pipe(fderr) < 0) {
82 failed_errno = errno;
83 if (need_in)
84 close_pair(fdin);
85 else if (cmd->in)
86 close(cmd->in);
87 if (need_out)
88 close_pair(fdout);
89 else if (cmd->out)
90 close(cmd->out);
91 fail_pipe:
92 error("cannot create pipe for %s: %s",
93 cmd->argv[0], strerror(failed_errno));
94 errno = failed_errno;
95 return -1;
96 }
97 cmd->err = fderr[0];
98 }
99
100 trace_argv_printf(cmd->argv, "trace: run_command:");
101
102 #ifndef WIN32
103 fflush(NULL);
104 cmd->pid = fork();
105 if (!cmd->pid) {
106 /*
107 * Redirect the channel to write syscall error messages to
108 * before redirecting the process's stderr so that all die()
109 * in subsequent call paths use the parent's stderr.
110 */
111 if (cmd->no_stderr || need_err) {
112 child_err = dup(2);
113 set_cloexec(child_err);
114 }
115 set_die_routine(die_child);
116
117 if (cmd->no_stdin)
118 dup_devnull(0);
119 else if (need_in) {
120 dup2(fdin[0], 0);
121 close_pair(fdin);
122 } else if (cmd->in) {
123 dup2(cmd->in, 0);
124 close(cmd->in);
125 }
126
127 if (cmd->no_stderr)
128 dup_devnull(2);
129 else if (need_err) {
130 dup2(fderr[1], 2);
131 close_pair(fderr);
132 }
133
134 if (cmd->no_stdout)
135 dup_devnull(1);
136 else if (cmd->stdout_to_stderr)
137 dup2(2, 1);
138 else if (need_out) {
139 dup2(fdout[1], 1);
140 close_pair(fdout);
141 } else if (cmd->out > 1) {
142 dup2(cmd->out, 1);
143 close(cmd->out);
144 }
145
146 if (cmd->dir && chdir(cmd->dir))
147 die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
148 cmd->dir);
149 if (cmd->env) {
150 for (; *cmd->env; cmd->env++) {
151 if (strchr(*cmd->env, '='))
152 putenv((char *)*cmd->env);
153 else
154 unsetenv(*cmd->env);
155 }
156 }
157 if (cmd->preexec_cb)
158 cmd->preexec_cb();
159 if (cmd->git_cmd) {
160 execv_git_cmd(cmd->argv);
161 } else {
162 execvp(cmd->argv[0], (char *const*) cmd->argv);
163 }
164 /*
165 * Do not check for cmd->silent_exec_failure; the parent
166 * process will check it when it sees this exit code.
167 */
168 if (errno == ENOENT)
169 exit(127);
170 else
171 die_errno("cannot exec '%s'", cmd->argv[0]);
172 }
173 if (cmd->pid < 0)
174 error("cannot fork() for %s: %s", cmd->argv[0],
175 strerror(failed_errno = errno));
176 #else
177 {
178 int s0 = -1, s1 = -1, s2 = -1; /* backups of stdin, stdout, stderr */
179 const char **sargv = cmd->argv;
180 char **env = environ;
181
182 if (cmd->no_stdin) {
183 s0 = dup(0);
184 dup_devnull(0);
185 } else if (need_in) {
186 s0 = dup(0);
187 dup2(fdin[0], 0);
188 } else if (cmd->in) {
189 s0 = dup(0);
190 dup2(cmd->in, 0);
191 }
192
193 if (cmd->no_stderr) {
194 s2 = dup(2);
195 dup_devnull(2);
196 } else if (need_err) {
197 s2 = dup(2);
198 dup2(fderr[1], 2);
199 }
200
201 if (cmd->no_stdout) {
202 s1 = dup(1);
203 dup_devnull(1);
204 } else if (cmd->stdout_to_stderr) {
205 s1 = dup(1);
206 dup2(2, 1);
207 } else if (need_out) {
208 s1 = dup(1);
209 dup2(fdout[1], 1);
210 } else if (cmd->out > 1) {
211 s1 = dup(1);
212 dup2(cmd->out, 1);
213 }
214
215 if (cmd->dir)
216 die("chdir in start_command() not implemented");
217 if (cmd->env)
218 env = make_augmented_environ(cmd->env);
219
220 if (cmd->git_cmd) {
221 cmd->argv = prepare_git_cmd(cmd->argv);
222 }
223
224 cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, env);
225 failed_errno = errno;
226 if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
227 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
228
229 if (cmd->env)
230 free_environ(env);
231 if (cmd->git_cmd)
232 free(cmd->argv);
233
234 cmd->argv = sargv;
235 if (s0 >= 0)
236 dup2(s0, 0), close(s0);
237 if (s1 >= 0)
238 dup2(s1, 1), close(s1);
239 if (s2 >= 0)
240 dup2(s2, 2), close(s2);
241 }
242 #endif
243
244 if (cmd->pid < 0) {
245 if (need_in)
246 close_pair(fdin);
247 else if (cmd->in)
248 close(cmd->in);
249 if (need_out)
250 close_pair(fdout);
251 else if (cmd->out)
252 close(cmd->out);
253 if (need_err)
254 close_pair(fderr);
255 errno = failed_errno;
256 return -1;
257 }
258
259 if (need_in)
260 close(fdin[0]);
261 else if (cmd->in)
262 close(cmd->in);
263
264 if (need_out)
265 close(fdout[1]);
266 else if (cmd->out)
267 close(cmd->out);
268
269 if (need_err)
270 close(fderr[1]);
271
272 return 0;
273 }
274
275 static int wait_or_whine(pid_t pid, const char *argv0, int silent_exec_failure)
276 {
277 int status, code = -1;
278 pid_t waiting;
279 int failed_errno = 0;
280
281 while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
282 ; /* nothing */
283
284 if (waiting < 0) {
285 failed_errno = errno;
286 error("waitpid for %s failed: %s", argv0, strerror(errno));
287 } else if (waiting != pid) {
288 error("waitpid is confused (%s)", argv0);
289 } else if (WIFSIGNALED(status)) {
290 code = WTERMSIG(status);
291 error("%s died of signal %d", argv0, code);
292 /*
293 * This return value is chosen so that code & 0xff
294 * mimics the exit code that a POSIX shell would report for
295 * a program that died from this signal.
296 */
297 code -= 128;
298 } else if (WIFEXITED(status)) {
299 code = WEXITSTATUS(status);
300 /*
301 * Convert special exit code when execvp failed.
302 */
303 if (code == 127) {
304 code = -1;
305 failed_errno = ENOENT;
306 if (!silent_exec_failure)
307 error("cannot run %s: %s", argv0,
308 strerror(ENOENT));
309 }
310 } else {
311 error("waitpid is confused (%s)", argv0);
312 }
313 errno = failed_errno;
314 return code;
315 }
316
317 int finish_command(struct child_process *cmd)
318 {
319 return wait_or_whine(cmd->pid, cmd->argv[0], cmd->silent_exec_failure);
320 }
321
322 int run_command(struct child_process *cmd)
323 {
324 int code = start_command(cmd);
325 if (code)
326 return code;
327 return finish_command(cmd);
328 }
329
330 static void prepare_run_command_v_opt(struct child_process *cmd,
331 const char **argv,
332 int opt)
333 {
334 memset(cmd, 0, sizeof(*cmd));
335 cmd->argv = argv;
336 cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
337 cmd->git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
338 cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
339 cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
340 }
341
342 int run_command_v_opt(const char **argv, int opt)
343 {
344 struct child_process cmd;
345 prepare_run_command_v_opt(&cmd, argv, opt);
346 return run_command(&cmd);
347 }
348
349 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
350 {
351 struct child_process cmd;
352 prepare_run_command_v_opt(&cmd, argv, opt);
353 cmd.dir = dir;
354 cmd.env = env;
355 return run_command(&cmd);
356 }
357
358 #ifdef WIN32
359 static unsigned __stdcall run_thread(void *data)
360 {
361 struct async *async = data;
362 return async->proc(async->fd_for_proc, async->data);
363 }
364 #endif
365
366 int start_async(struct async *async)
367 {
368 int pipe_out[2];
369
370 if (pipe(pipe_out) < 0)
371 return error("cannot create pipe: %s", strerror(errno));
372 async->out = pipe_out[0];
373
374 #ifndef WIN32
375 /* Flush stdio before fork() to avoid cloning buffers */
376 fflush(NULL);
377
378 async->pid = fork();
379 if (async->pid < 0) {
380 error("fork (async) failed: %s", strerror(errno));
381 close_pair(pipe_out);
382 return -1;
383 }
384 if (!async->pid) {
385 close(pipe_out[0]);
386 exit(!!async->proc(pipe_out[1], async->data));
387 }
388 close(pipe_out[1]);
389 #else
390 async->fd_for_proc = pipe_out[1];
391 async->tid = (HANDLE) _beginthreadex(NULL, 0, run_thread, async, 0, NULL);
392 if (!async->tid) {
393 error("cannot create thread: %s", strerror(errno));
394 close_pair(pipe_out);
395 return -1;
396 }
397 #endif
398 return 0;
399 }
400
401 int finish_async(struct async *async)
402 {
403 #ifndef WIN32
404 int ret = wait_or_whine(async->pid, "child process", 0);
405 #else
406 DWORD ret = 0;
407 if (WaitForSingleObject(async->tid, INFINITE) != WAIT_OBJECT_0)
408 ret = error("waiting for thread failed: %lu", GetLastError());
409 else if (!GetExitCodeThread(async->tid, &ret))
410 ret = error("cannot get thread exit code: %lu", GetLastError());
411 CloseHandle(async->tid);
412 #endif
413 return ret;
414 }
415
416 int run_hook(const char *index_file, const char *name, ...)
417 {
418 struct child_process hook;
419 const char **argv = NULL, *env[2];
420 char index[PATH_MAX];
421 va_list args;
422 int ret;
423 size_t i = 0, alloc = 0;
424
425 if (access(git_path("hooks/%s", name), X_OK) < 0)
426 return 0;
427
428 va_start(args, name);
429 ALLOC_GROW(argv, i + 1, alloc);
430 argv[i++] = git_path("hooks/%s", name);
431 while (argv[i-1]) {
432 ALLOC_GROW(argv, i + 1, alloc);
433 argv[i++] = va_arg(args, const char *);
434 }
435 va_end(args);
436
437 memset(&hook, 0, sizeof(hook));
438 hook.argv = argv;
439 hook.no_stdin = 1;
440 hook.stdout_to_stderr = 1;
441 if (index_file) {
442 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file);
443 env[0] = index;
444 env[1] = NULL;
445 hook.env = env;
446 }
447
448 ret = run_command(&hook);
449 free(argv);
450 return ret;
451 }