1#include "cache.h"
2#include "run-command.h"
3#include "exec_cmd.h"
4#include "sigchain.h"
5#include "argv-array.h"
6void child_process_init(struct child_process *child)
8{
9 memset(child, 0, sizeof(*child));
10 argv_array_init(&child->args);
11 argv_array_init(&child->env_array);
12}
13void child_process_clear(struct child_process *child)
15{
16 argv_array_clear(&child->args);
17 argv_array_clear(&child->env_array);
18}
19struct child_to_clean {
21 pid_t pid;
22 struct child_to_clean *next;
23};
24static struct child_to_clean *children_to_clean;
25static int installed_child_cleanup_handler;
26static void cleanup_children(int sig, int in_signal)
28{
29 while (children_to_clean) {
30 struct child_to_clean *p = children_to_clean;
31 children_to_clean = p->next;
32 kill(p->pid, sig);
33 if (!in_signal)
34 free(p);
35 }
36}
37static void cleanup_children_on_signal(int sig)
39{
40 cleanup_children(sig, 1);
41 sigchain_pop(sig);
42 raise(sig);
43}
44static void cleanup_children_on_exit(void)
46{
47 cleanup_children(SIGTERM, 0);
48}
49static void mark_child_for_cleanup(pid_t pid)
51{
52 struct child_to_clean *p = xmalloc(sizeof(*p));
53 p->pid = pid;
54 p->next = children_to_clean;
55 children_to_clean = p;
56 if (!installed_child_cleanup_handler) {
58 atexit(cleanup_children_on_exit);
59 sigchain_push_common(cleanup_children_on_signal);
60 installed_child_cleanup_handler = 1;
61 }
62}
63static void clear_child_for_cleanup(pid_t pid)
65{
66 struct child_to_clean **pp;
67 for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
69 struct child_to_clean *clean_me = *pp;
70 if (clean_me->pid == pid) {
72 *pp = clean_me->next;
73 free(clean_me);
74 return;
75 }
76 }
77}
78static inline void close_pair(int fd[2])
80{
81 close(fd[0]);
82 close(fd[1]);
83}
84#ifndef GIT_WINDOWS_NATIVE
86static inline void dup_devnull(int to)
87{
88 int fd = open("/dev/null", O_RDWR);
89 if (fd < 0)
90 die_errno(_("open /dev/null failed"));
91 if (dup2(fd, to) < 0)
92 die_errno(_("dup2(%d,%d) failed"), fd, to);
93 close(fd);
94}
95#endif
96static char *locate_in_PATH(const char *file)
98{
99 const char *p = getenv("PATH");
100 struct strbuf buf = STRBUF_INIT;
101 if (!p || !*p)
103 return NULL;
104 while (1) {
106 const char *end = strchrnul(p, ':');
107 strbuf_reset(&buf);
109 /* POSIX specifies an empty entry as the current directory. */
111 if (end != p) {
112 strbuf_add(&buf, p, end - p);
113 strbuf_addch(&buf, '/');
114 }
115 strbuf_addstr(&buf, file);
116 if (!access(buf.buf, F_OK))
118 return strbuf_detach(&buf, NULL);
119 if (!*end)
121 break;
122 p = end + 1;
123 }
124 strbuf_release(&buf);
126 return NULL;
127}
128static int exists_in_PATH(const char *file)
130{
131 char *r = locate_in_PATH(file);
132 free(r);
133 return r != NULL;
134}
135int sane_execvp(const char *file, char * const argv[])
137{
138 if (!execvp(file, argv))
139 return 0; /* cannot happen ;-) */
140 /*
142 * When a command can't be found because one of the directories
143 * listed in $PATH is unsearchable, execvp reports EACCES, but
144 * careful usability testing (read: analysis of occasional bug
145 * reports) reveals that "No such file or directory" is more
146 * intuitive.
147 *
148 * We avoid commands with "/", because execvp will not do $PATH
149 * lookups in that case.
150 *
151 * The reassignment of EACCES to errno looks like a no-op below,
152 * but we need to protect against exists_in_PATH overwriting errno.
153 */
154 if (errno == EACCES && !strchr(file, '/'))
155 errno = exists_in_PATH(file) ? EACCES : ENOENT;
156 else if (errno == ENOTDIR && !strchr(file, '/'))
157 errno = ENOENT;
158 return -1;
159}
160static const char **prepare_shell_cmd(const char **argv)
162{
163 int argc, nargc = 0;
164 const char **nargv;
165 for (argc = 0; argv[argc]; argc++)
167 ; /* just counting */
168 /* +1 for NULL, +3 for "sh -c" plus extra $0 */
169 nargv = xmalloc(sizeof(*nargv) * (argc + 1 + 3));
170 if (argc < 1)
172 die("BUG: shell command is empty");
173 if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
175#ifndef GIT_WINDOWS_NATIVE
176 nargv[nargc++] = SHELL_PATH;
177#else
178 nargv[nargc++] = "sh";
179#endif
180 nargv[nargc++] = "-c";
181 if (argc < 2)
183 nargv[nargc++] = argv[0];
184 else {
185 struct strbuf arg0 = STRBUF_INIT;
186 strbuf_addf(&arg0, "%s \"$@\"", argv[0]);
187 nargv[nargc++] = strbuf_detach(&arg0, NULL);
188 }
189 }
190 for (argc = 0; argv[argc]; argc++)
192 nargv[nargc++] = argv[argc];
193 nargv[nargc] = NULL;
194 return nargv;
196}
197#ifndef GIT_WINDOWS_NATIVE
199static int execv_shell_cmd(const char **argv)
200{
201 const char **nargv = prepare_shell_cmd(argv);
202 trace_argv_printf(nargv, "trace: exec:");
203 sane_execvp(nargv[0], (char **)nargv);
204 free(nargv);
205 return -1;
206}
207#endif
208#ifndef GIT_WINDOWS_NATIVE
210static int child_notifier = -1;
211static void notify_parent(void)
213{
214 /*
215 * execvp failed. If possible, we'd like to let start_command
216 * know, so failures like ENOENT can be handled right away; but
217 * otherwise, finish_command will still report the error.
218 */
219 xwrite(child_notifier, "", 1);
220}
221#endif
222static inline void set_cloexec(int fd)
224{
225 int flags = fcntl(fd, F_GETFD);
226 if (flags >= 0)
227 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
228}
229static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
231{
232 int status, code = -1;
233 pid_t waiting;
234 int failed_errno = 0;
235 while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
237 ; /* nothing */
238 if (in_signal)
239 return 0;
240 if (waiting < 0) {
242 failed_errno = errno;
243 error("waitpid for %s failed: %s", argv0, strerror(errno));
244 } else if (waiting != pid) {
245 error("waitpid is confused (%s)", argv0);
246 } else if (WIFSIGNALED(status)) {
247 code = WTERMSIG(status);
248 if (code != SIGINT && code != SIGQUIT)
249 error("%s died of signal %d", argv0, code);
250 /*
251 * This return value is chosen so that code & 0xff
252 * mimics the exit code that a POSIX shell would report for
253 * a program that died from this signal.
254 */
255 code += 128;
256 } else if (WIFEXITED(status)) {
257 code = WEXITSTATUS(status);
258 /*
259 * Convert special exit code when execvp failed.
260 */
261 if (code == 127) {
262 code = -1;
263 failed_errno = ENOENT;
264 }
265 } else {
266 error("waitpid is confused (%s)", argv0);
267 }
268 clear_child_for_cleanup(pid);
270 errno = failed_errno;
272 return code;
273}
274int start_command(struct child_process *cmd)
276{
277 int need_in, need_out, need_err;
278 int fdin[2], fdout[2], fderr[2];
279 int failed_errno;
280 char *str;
281 if (!cmd->argv)
283 cmd->argv = cmd->args.argv;
284 if (!cmd->env)
285 cmd->env = cmd->env_array.argv;
286 /*
288 * In case of errors we must keep the promise to close FDs
289 * that have been passed in via ->in and ->out.
290 */
291 need_in = !cmd->no_stdin && cmd->in < 0;
293 if (need_in) {
294 if (pipe(fdin) < 0) {
295 failed_errno = errno;
296 if (cmd->out > 0)
297 close(cmd->out);
298 str = "standard input";
299 goto fail_pipe;
300 }
301 cmd->in = fdin[1];
302 }
303 need_out = !cmd->no_stdout
305 && !cmd->stdout_to_stderr
306 && cmd->out < 0;
307 if (need_out) {
308 if (pipe(fdout) < 0) {
309 failed_errno = errno;
310 if (need_in)
311 close_pair(fdin);
312 else if (cmd->in)
313 close(cmd->in);
314 str = "standard output";
315 goto fail_pipe;
316 }
317 cmd->out = fdout[0];
318 }
319 need_err = !cmd->no_stderr && cmd->err < 0;
321 if (need_err) {
322 if (pipe(fderr) < 0) {
323 failed_errno = errno;
324 if (need_in)
325 close_pair(fdin);
326 else if (cmd->in)
327 close(cmd->in);
328 if (need_out)
329 close_pair(fdout);
330 else if (cmd->out)
331 close(cmd->out);
332 str = "standard error";
333fail_pipe:
334 error("cannot create %s pipe for %s: %s",
335 str, cmd->argv[0], strerror(failed_errno));
336 child_process_clear(cmd);
337 errno = failed_errno;
338 return -1;
339 }
340 cmd->err = fderr[0];
341 }
342 trace_argv_printf(cmd->argv, "trace: run_command:");
344 fflush(NULL);
345#ifndef GIT_WINDOWS_NATIVE
347{
348 int notify_pipe[2];
349 if (pipe(notify_pipe))
350 notify_pipe[0] = notify_pipe[1] = -1;
351 cmd->pid = fork();
353 failed_errno = errno;
354 if (!cmd->pid) {
355 /*
356 * Redirect the channel to write syscall error messages to
357 * before redirecting the process's stderr so that all die()
358 * in subsequent call paths use the parent's stderr.
359 */
360 if (cmd->no_stderr || need_err) {
361 int child_err = dup(2);
362 set_cloexec(child_err);
363 set_error_handle(fdopen(child_err, "w"));
364 }
365 close(notify_pipe[0]);
367 set_cloexec(notify_pipe[1]);
368 child_notifier = notify_pipe[1];
369 atexit(notify_parent);
370 if (cmd->no_stdin)
372 dup_devnull(0);
373 else if (need_in) {
374 dup2(fdin[0], 0);
375 close_pair(fdin);
376 } else if (cmd->in) {
377 dup2(cmd->in, 0);
378 close(cmd->in);
379 }
380 if (cmd->no_stderr)
382 dup_devnull(2);
383 else if (need_err) {
384 dup2(fderr[1], 2);
385 close_pair(fderr);
386 } else if (cmd->err > 1) {
387 dup2(cmd->err, 2);
388 close(cmd->err);
389 }
390 if (cmd->no_stdout)
392 dup_devnull(1);
393 else if (cmd->stdout_to_stderr)
394 dup2(2, 1);
395 else if (need_out) {
396 dup2(fdout[1], 1);
397 close_pair(fdout);
398 } else if (cmd->out > 1) {
399 dup2(cmd->out, 1);
400 close(cmd->out);
401 }
402 if (cmd->dir && chdir(cmd->dir))
404 die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
405 cmd->dir);
406 if (cmd->env) {
407 for (; *cmd->env; cmd->env++) {
408 if (strchr(*cmd->env, '='))
409 putenv((char *)*cmd->env);
410 else
411 unsetenv(*cmd->env);
412 }
413 }
414 if (cmd->git_cmd)
415 execv_git_cmd(cmd->argv);
416 else if (cmd->use_shell)
417 execv_shell_cmd(cmd->argv);
418 else
419 sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
420 if (errno == ENOENT) {
421 if (!cmd->silent_exec_failure)
422 error("cannot run %s: %s", cmd->argv[0],
423 strerror(ENOENT));
424 exit(127);
425 } else {
426 die_errno("cannot exec '%s'", cmd->argv[0]);
427 }
428 }
429 if (cmd->pid < 0)
430 error("cannot fork() for %s: %s", cmd->argv[0],
431 strerror(errno));
432 else if (cmd->clean_on_exit)
433 mark_child_for_cleanup(cmd->pid);
434 /*
436 * Wait for child's execvp. If the execvp succeeds (or if fork()
437 * failed), EOF is seen immediately by the parent. Otherwise, the
438 * child process sends a single byte.
439 * Note that use of this infrastructure is completely advisory,
440 * therefore, we keep error checks minimal.
441 */
442 close(notify_pipe[1]);
443 if (read(notify_pipe[0], ¬ify_pipe[1], 1) == 1) {
444 /*
445 * At this point we know that fork() succeeded, but execvp()
446 * failed. Errors have been reported to our stderr.
447 */
448 wait_or_whine(cmd->pid, cmd->argv[0], 0);
449 failed_errno = errno;
450 cmd->pid = -1;
451 }
452 close(notify_pipe[0]);
453}
454#else
455{
456 int fhin = 0, fhout = 1, fherr = 2;
457 const char **sargv = cmd->argv;
458 if (cmd->no_stdin)
460 fhin = open("/dev/null", O_RDWR);
461 else if (need_in)
462 fhin = dup(fdin[0]);
463 else if (cmd->in)
464 fhin = dup(cmd->in);
465 if (cmd->no_stderr)
467 fherr = open("/dev/null", O_RDWR);
468 else if (need_err)
469 fherr = dup(fderr[1]);
470 else if (cmd->err > 2)
471 fherr = dup(cmd->err);
472 if (cmd->no_stdout)
474 fhout = open("/dev/null", O_RDWR);
475 else if (cmd->stdout_to_stderr)
476 fhout = dup(fherr);
477 else if (need_out)
478 fhout = dup(fdout[1]);
479 else if (cmd->out > 1)
480 fhout = dup(cmd->out);
481 if (cmd->git_cmd)
483 cmd->argv = prepare_git_cmd(cmd->argv);
484 else if (cmd->use_shell)
485 cmd->argv = prepare_shell_cmd(cmd->argv);
486 cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
488 cmd->dir, fhin, fhout, fherr);
489 failed_errno = errno;
490 if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
491 error("cannot spawn %s: %s", cmd->argv[0], strerror(errno));
492 if (cmd->clean_on_exit && cmd->pid >= 0)
493 mark_child_for_cleanup(cmd->pid);
494 if (cmd->git_cmd)
496 free(cmd->argv);
497 cmd->argv = sargv;
499 if (fhin != 0)
500 close(fhin);
501 if (fhout != 1)
502 close(fhout);
503 if (fherr != 2)
504 close(fherr);
505}
506#endif
507 if (cmd->pid < 0) {
509 if (need_in)
510 close_pair(fdin);
511 else if (cmd->in)
512 close(cmd->in);
513 if (need_out)
514 close_pair(fdout);
515 else if (cmd->out)
516 close(cmd->out);
517 if (need_err)
518 close_pair(fderr);
519 else if (cmd->err)
520 close(cmd->err);
521 child_process_clear(cmd);
522 errno = failed_errno;
523 return -1;
524 }
525 if (need_in)
527 close(fdin[0]);
528 else if (cmd->in)
529 close(cmd->in);
530 if (need_out)
532 close(fdout[1]);
533 else if (cmd->out)
534 close(cmd->out);
535 if (need_err)
537 close(fderr[1]);
538 else if (cmd->err)
539 close(cmd->err);
540 return 0;
542}
543int finish_command(struct child_process *cmd)
545{
546 int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
547 child_process_clear(cmd);
548 return ret;
549}
550int finish_command_in_signal(struct child_process *cmd)
552{
553 return wait_or_whine(cmd->pid, cmd->argv[0], 1);
554}
555int run_command(struct child_process *cmd)
558{
559 int code;
560 if (cmd->out < 0 || cmd->err < 0)
562 die("BUG: run_command with a pipe can cause deadlock");
563 code = start_command(cmd);
565 if (code)
566 return code;
567 return finish_command(cmd);
568}
569int run_command_v_opt(const char **argv, int opt)
571{
572 return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
573}
574int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
576{
577 struct child_process cmd = CHILD_PROCESS_INIT;
578 cmd.argv = argv;
579 cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
580 cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
581 cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
582 cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
583 cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
584 cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
585 cmd.dir = dir;
586 cmd.env = env;
587 return run_command(&cmd);
588}
589#ifndef NO_PTHREADS
591static pthread_t main_thread;
592static int main_thread_set;
593static pthread_key_t async_key;
594static pthread_key_t async_die_counter;
595static void *run_thread(void *data)
597{
598 struct async *async = data;
599 intptr_t ret;
600 pthread_setspecific(async_key, async);
602 ret = async->proc(async->proc_in, async->proc_out, async->data);
603 return (void *)ret;
604}
605static NORETURN void die_async(const char *err, va_list params)
607{
608 vreportf("fatal: ", err, params);
609 if (in_async()) {
611 struct async *async = pthread_getspecific(async_key);
612 if (async->proc_in >= 0)
613 close(async->proc_in);
614 if (async->proc_out >= 0)
615 close(async->proc_out);
616 pthread_exit((void *)128);
617 }
618 exit(128);
620}
621static int async_die_is_recursing(void)
623{
624 void *ret = pthread_getspecific(async_die_counter);
625 pthread_setspecific(async_die_counter, (void *)1);
626 return ret != NULL;
627}
628int in_async(void)
630{
631 if (!main_thread_set)
632 return 0; /* no asyncs started yet */
633 return !pthread_equal(main_thread, pthread_self());
634}
635#else
637static struct {
639 void (**handlers)(void);
640 size_t nr;
641 size_t alloc;
642} git_atexit_hdlrs;
643static int git_atexit_installed;
645static void git_atexit_dispatch(void)
647{
648 size_t i;
649 for (i=git_atexit_hdlrs.nr ; i ; i--)
651 git_atexit_hdlrs.handlers[i-1]();
652}
653static void git_atexit_clear(void)
655{
656 free(git_atexit_hdlrs.handlers);
657 memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
658 git_atexit_installed = 0;
659}
660#undef atexit
662int git_atexit(void (*handler)(void))
663{
664 ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
665 git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
666 if (!git_atexit_installed) {
667 if (atexit(&git_atexit_dispatch))
668 return -1;
669 git_atexit_installed = 1;
670 }
671 return 0;
672}
673#define atexit git_atexit
674static int process_is_async;
676int in_async(void)
677{
678 return process_is_async;
679}
680#endif
682int start_async(struct async *async)
684{
685 int need_in, need_out;
686 int fdin[2], fdout[2];
687 int proc_in, proc_out;
688 need_in = async->in < 0;
690 if (need_in) {
691 if (pipe(fdin) < 0) {
692 if (async->out > 0)
693 close(async->out);
694 return error("cannot create pipe: %s", strerror(errno));
695 }
696 async->in = fdin[1];
697 }
698 need_out = async->out < 0;
700 if (need_out) {
701 if (pipe(fdout) < 0) {
702 if (need_in)
703 close_pair(fdin);
704 else if (async->in)
705 close(async->in);
706 return error("cannot create pipe: %s", strerror(errno));
707 }
708 async->out = fdout[0];
709 }
710 if (need_in)
712 proc_in = fdin[0];
713 else if (async->in)
714 proc_in = async->in;
715 else
716 proc_in = -1;
717 if (need_out)
719 proc_out = fdout[1];
720 else if (async->out)
721 proc_out = async->out;
722 else
723 proc_out = -1;
724#ifdef NO_PTHREADS
726 /* Flush stdio before fork() to avoid cloning buffers */
727 fflush(NULL);
728 async->pid = fork();
730 if (async->pid < 0) {
731 error("fork (async) failed: %s", strerror(errno));
732 goto error;
733 }
734 if (!async->pid) {
735 if (need_in)
736 close(fdin[1]);
737 if (need_out)
738 close(fdout[0]);
739 git_atexit_clear();
740 process_is_async = 1;
741 exit(!!async->proc(proc_in, proc_out, async->data));
742 }
743 mark_child_for_cleanup(async->pid);
745 if (need_in)
747 close(fdin[0]);
748 else if (async->in)
749 close(async->in);
750 if (need_out)
752 close(fdout[1]);
753 else if (async->out)
754 close(async->out);
755#else
756 if (!main_thread_set) {
757 /*
758 * We assume that the first time that start_async is called
759 * it is from the main thread.
760 */
761 main_thread_set = 1;
762 main_thread = pthread_self();
763 pthread_key_create(&async_key, NULL);
764 pthread_key_create(&async_die_counter, NULL);
765 set_die_routine(die_async);
766 set_die_is_recursing_routine(async_die_is_recursing);
767 }
768 if (proc_in >= 0)
770 set_cloexec(proc_in);
771 if (proc_out >= 0)
772 set_cloexec(proc_out);
773 async->proc_in = proc_in;
774 async->proc_out = proc_out;
775 {
776 int err = pthread_create(&async->tid, NULL, run_thread, async);
777 if (err) {
778 error("cannot create thread: %s", strerror(err));
779 goto error;
780 }
781 }
782#endif
783 return 0;
784error:
786 if (need_in)
787 close_pair(fdin);
788 else if (async->in)
789 close(async->in);
790 if (need_out)
792 close_pair(fdout);
793 else if (async->out)
794 close(async->out);
795 return -1;
796}
797int finish_async(struct async *async)
799{
800#ifdef NO_PTHREADS
801 return wait_or_whine(async->pid, "child process", 0);
802#else
803 void *ret = (void *)(intptr_t)(-1);
804 if (pthread_join(async->tid, &ret))
806 error("pthread_join failed");
807 return (int)(intptr_t)ret;
808#endif
809}
810const char *find_hook(const char *name)
812{
813 static struct strbuf path = STRBUF_INIT;
814 strbuf_reset(&path);
816 strbuf_git_path(&path, "hooks/%s", name);
817 if (access(path.buf, X_OK) < 0)
818 return NULL;
819 return path.buf;
820}
821int run_hook_ve(const char *const *env, const char *name, va_list args)
823{
824 struct child_process hook = CHILD_PROCESS_INIT;
825 const char *p;
826 p = find_hook(name);
828 if (!p)
829 return 0;
830 argv_array_push(&hook.args, p);
832 while ((p = va_arg(args, const char *)))
833 argv_array_push(&hook.args, p);
834 hook.env = env;
835 hook.no_stdin = 1;
836 hook.stdout_to_stderr = 1;
837 return run_command(&hook);
839}
840int run_hook_le(const char *const *env, const char *name, ...)
842{
843 va_list args;
844 int ret;
845 va_start(args, name);
847 ret = run_hook_ve(env, name, args);
848 va_end(args);
849 return ret;
851}
852int capture_command(struct child_process *cmd, struct strbuf *buf, size_t hint)
854{
855 cmd->out = -1;
856 if (start_command(cmd) < 0)
857 return -1;
858 if (strbuf_read(buf, cmd->out, hint) < 0) {
860 close(cmd->out);
861 finish_command(cmd); /* throw away exit code */
862 return -1;
863 }
864 close(cmd->out);
866 return finish_command(cmd);
867}