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submodules doc: update documentation for "." used for submodule branches
[alt-git.git] / run-command.c
blob33bc63a1de8d41b52a0ec353cf80b0f2e65dc8fd
1 #include "cache.h"
2 #include "run-command.h"
3 #include "exec_cmd.h"
4 #include "sigchain.h"
5 #include "argv-array.h"
6 #include "thread-utils.h"
7 #include "strbuf.h"
8
9 void child_process_init(struct child_process *child)
10 {
11 memset(child, 0, sizeof(*child));
12 argv_array_init(&child->args);
13 argv_array_init(&child->env_array);
14 }
15
16 void child_process_clear(struct child_process *child)
17 {
18 argv_array_clear(&child->args);
19 argv_array_clear(&child->env_array);
20 }
21
22 struct child_to_clean {
23 pid_t pid;
24 struct child_to_clean *next;
25 };
26 static struct child_to_clean *children_to_clean;
27 static int installed_child_cleanup_handler;
28
29 static void cleanup_children(int sig, int in_signal)
30 {
31 while (children_to_clean) {
32 struct child_to_clean *p = children_to_clean;
33 children_to_clean = p->next;
34 kill(p->pid, sig);
35 if (!in_signal)
36 free(p);
37 }
38 }
39
40 static void cleanup_children_on_signal(int sig)
41 {
42 cleanup_children(sig, 1);
43 sigchain_pop(sig);
44 raise(sig);
45 }
46
47 static void cleanup_children_on_exit(void)
48 {
49 cleanup_children(SIGTERM, 0);
50 }
51
52 static void mark_child_for_cleanup(pid_t pid)
53 {
54 struct child_to_clean *p = xmalloc(sizeof(*p));
55 p->pid = pid;
56 p->next = children_to_clean;
57 children_to_clean = p;
58
59 if (!installed_child_cleanup_handler) {
60 atexit(cleanup_children_on_exit);
61 sigchain_push_common(cleanup_children_on_signal);
62 installed_child_cleanup_handler = 1;
63 }
64 }
65
66 static void clear_child_for_cleanup(pid_t pid)
67 {
68 struct child_to_clean **pp;
69
70 for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
71 struct child_to_clean *clean_me = *pp;
72
73 if (clean_me->pid == pid) {
74 *pp = clean_me->next;
75 free(clean_me);
76 return;
77 }
78 }
79 }
80
81 static inline void close_pair(int fd[2])
82 {
83 close(fd[0]);
84 close(fd[1]);
85 }
86
87 #ifndef GIT_WINDOWS_NATIVE
88 static inline void dup_devnull(int to)
89 {
90 int fd = open("/dev/null", O_RDWR);
91 if (fd < 0)
92 die_errno(_("open /dev/null failed"));
93 if (dup2(fd, to) < 0)
94 die_errno(_("dup2(%d,%d) failed"), fd, to);
95 close(fd);
96 }
97 #endif
98
99 static char *locate_in_PATH(const char *file)
100 {
101 const char *p = getenv("PATH");
102 struct strbuf buf = STRBUF_INIT;
103
104 if (!p || !*p)
105 return NULL;
106
107 while (1) {
108 const char *end = strchrnul(p, ':');
109
110 strbuf_reset(&buf);
111
112 /* POSIX specifies an empty entry as the current directory. */
113 if (end != p) {
114 strbuf_add(&buf, p, end - p);
115 strbuf_addch(&buf, '/');
116 }
117 strbuf_addstr(&buf, file);
118
119 if (!access(buf.buf, F_OK))
120 return strbuf_detach(&buf, NULL);
121
122 if (!*end)
123 break;
124 p = end + 1;
125 }
126
127 strbuf_release(&buf);
128 return NULL;
129 }
130
131 static int exists_in_PATH(const char *file)
132 {
133 char *r = locate_in_PATH(file);
134 free(r);
135 return r != NULL;
136 }
137
138 int sane_execvp(const char *file, char * const argv[])
139 {
140 if (!execvp(file, argv))
141 return 0; /* cannot happen ;-) */
142
143 /*
144 * When a command can't be found because one of the directories
145 * listed in $PATH is unsearchable, execvp reports EACCES, but
146 * careful usability testing (read: analysis of occasional bug
147 * reports) reveals that "No such file or directory" is more
148 * intuitive.
149 *
150 * We avoid commands with "/", because execvp will not do $PATH
151 * lookups in that case.
152 *
153 * The reassignment of EACCES to errno looks like a no-op below,
154 * but we need to protect against exists_in_PATH overwriting errno.
155 */
156 if (errno == EACCES && !strchr(file, '/'))
157 errno = exists_in_PATH(file) ? EACCES : ENOENT;
158 else if (errno == ENOTDIR && !strchr(file, '/'))
159 errno = ENOENT;
160 return -1;
161 }
162
163 static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
164 {
165 if (!argv[0])
166 die("BUG: shell command is empty");
167
168 if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
169 #ifndef GIT_WINDOWS_NATIVE
170 argv_array_push(out, SHELL_PATH);
171 #else
172 argv_array_push(out, "sh");
173 #endif
174 argv_array_push(out, "-c");
175
176 /*
177 * If we have no extra arguments, we do not even need to
178 * bother with the "$@" magic.
179 */
180 if (!argv[1])
181 argv_array_push(out, argv[0]);
182 else
183 argv_array_pushf(out, "%s \"$@\"", argv[0]);
184 }
185
186 argv_array_pushv(out, argv);
187 return out->argv;
188 }
189
190 #ifndef GIT_WINDOWS_NATIVE
191 static int execv_shell_cmd(const char **argv)
192 {
193 struct argv_array nargv = ARGV_ARRAY_INIT;
194 prepare_shell_cmd(&nargv, argv);
195 trace_argv_printf(nargv.argv, "trace: exec:");
196 sane_execvp(nargv.argv[0], (char **)nargv.argv);
197 argv_array_clear(&nargv);
198 return -1;
199 }
200 #endif
201
202 #ifndef GIT_WINDOWS_NATIVE
203 static int child_notifier = -1;
204
205 static void notify_parent(void)
206 {
207 /*
208 * execvp failed. If possible, we'd like to let start_command
209 * know, so failures like ENOENT can be handled right away; but
210 * otherwise, finish_command will still report the error.
211 */
212 xwrite(child_notifier, "", 1);
213 }
214 #endif
215
216 static inline void set_cloexec(int fd)
217 {
218 int flags = fcntl(fd, F_GETFD);
219 if (flags >= 0)
220 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
221 }
222
223 static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
224 {
225 int status, code = -1;
226 pid_t waiting;
227 int failed_errno = 0;
228
229 while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
230 ; /* nothing */
231 if (in_signal)
232 return 0;
233
234 if (waiting < 0) {
235 failed_errno = errno;
236 error_errno("waitpid for %s failed", argv0);
237 } else if (waiting != pid) {
238 error("waitpid is confused (%s)", argv0);
239 } else if (WIFSIGNALED(status)) {
240 code = WTERMSIG(status);
241 if (code != SIGINT && code != SIGQUIT && code != SIGPIPE)
242 error("%s died of signal %d", argv0, code);
243 /*
244 * This return value is chosen so that code & 0xff
245 * mimics the exit code that a POSIX shell would report for
246 * a program that died from this signal.
247 */
248 code += 128;
249 } else if (WIFEXITED(status)) {
250 code = WEXITSTATUS(status);
251 /*
252 * Convert special exit code when execvp failed.
253 */
254 if (code == 127) {
255 code = -1;
256 failed_errno = ENOENT;
257 }
258 } else {
259 error("waitpid is confused (%s)", argv0);
260 }
261
262 clear_child_for_cleanup(pid);
263
264 errno = failed_errno;
265 return code;
266 }
267
268 int start_command(struct child_process *cmd)
269 {
270 int need_in, need_out, need_err;
271 int fdin[2], fdout[2], fderr[2];
272 int failed_errno;
273 char *str;
274
275 if (!cmd->argv)
276 cmd->argv = cmd->args.argv;
277 if (!cmd->env)
278 cmd->env = cmd->env_array.argv;
279
280 /*
281 * In case of errors we must keep the promise to close FDs
282 * that have been passed in via ->in and ->out.
283 */
284
285 need_in = !cmd->no_stdin && cmd->in < 0;
286 if (need_in) {
287 if (pipe(fdin) < 0) {
288 failed_errno = errno;
289 if (cmd->out > 0)
290 close(cmd->out);
291 str = "standard input";
292 goto fail_pipe;
293 }
294 cmd->in = fdin[1];
295 }
296
297 need_out = !cmd->no_stdout
298 && !cmd->stdout_to_stderr
299 && cmd->out < 0;
300 if (need_out) {
301 if (pipe(fdout) < 0) {
302 failed_errno = errno;
303 if (need_in)
304 close_pair(fdin);
305 else if (cmd->in)
306 close(cmd->in);
307 str = "standard output";
308 goto fail_pipe;
309 }
310 cmd->out = fdout[0];
311 }
312
313 need_err = !cmd->no_stderr && cmd->err < 0;
314 if (need_err) {
315 if (pipe(fderr) < 0) {
316 failed_errno = errno;
317 if (need_in)
318 close_pair(fdin);
319 else if (cmd->in)
320 close(cmd->in);
321 if (need_out)
322 close_pair(fdout);
323 else if (cmd->out)
324 close(cmd->out);
325 str = "standard error";
326 fail_pipe:
327 error("cannot create %s pipe for %s: %s",
328 str, cmd->argv[0], strerror(failed_errno));
329 child_process_clear(cmd);
330 errno = failed_errno;
331 return -1;
332 }
333 cmd->err = fderr[0];
334 }
335
336 trace_argv_printf(cmd->argv, "trace: run_command:");
337 fflush(NULL);
338
339 #ifndef GIT_WINDOWS_NATIVE
340 {
341 int notify_pipe[2];
342 if (pipe(notify_pipe))
343 notify_pipe[0] = notify_pipe[1] = -1;
344
345 cmd->pid = fork();
346 failed_errno = errno;
347 if (!cmd->pid) {
348 /*
349 * Redirect the channel to write syscall error messages to
350 * before redirecting the process's stderr so that all die()
351 * in subsequent call paths use the parent's stderr.
352 */
353 if (cmd->no_stderr || need_err) {
354 int child_err = dup(2);
355 set_cloexec(child_err);
356 set_error_handle(fdopen(child_err, "w"));
357 }
358
359 close(notify_pipe[0]);
360 set_cloexec(notify_pipe[1]);
361 child_notifier = notify_pipe[1];
362 atexit(notify_parent);
363
364 if (cmd->no_stdin)
365 dup_devnull(0);
366 else if (need_in) {
367 dup2(fdin[0], 0);
368 close_pair(fdin);
369 } else if (cmd->in) {
370 dup2(cmd->in, 0);
371 close(cmd->in);
372 }
373
374 if (cmd->no_stderr)
375 dup_devnull(2);
376 else if (need_err) {
377 dup2(fderr[1], 2);
378 close_pair(fderr);
379 } else if (cmd->err > 1) {
380 dup2(cmd->err, 2);
381 close(cmd->err);
382 }
383
384 if (cmd->no_stdout)
385 dup_devnull(1);
386 else if (cmd->stdout_to_stderr)
387 dup2(2, 1);
388 else if (need_out) {
389 dup2(fdout[1], 1);
390 close_pair(fdout);
391 } else if (cmd->out > 1) {
392 dup2(cmd->out, 1);
393 close(cmd->out);
394 }
395
396 if (cmd->dir && chdir(cmd->dir))
397 die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
398 cmd->dir);
399 if (cmd->env) {
400 for (; *cmd->env; cmd->env++) {
401 if (strchr(*cmd->env, '='))
402 putenv((char *)*cmd->env);
403 else
404 unsetenv(*cmd->env);
405 }
406 }
407 if (cmd->git_cmd)
408 execv_git_cmd(cmd->argv);
409 else if (cmd->use_shell)
410 execv_shell_cmd(cmd->argv);
411 else
412 sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
413 if (errno == ENOENT) {
414 if (!cmd->silent_exec_failure)
415 error("cannot run %s: %s", cmd->argv[0],
416 strerror(ENOENT));
417 exit(127);
418 } else {
419 die_errno("cannot exec '%s'", cmd->argv[0]);
420 }
421 }
422 if (cmd->pid < 0)
423 error_errno("cannot fork() for %s", cmd->argv[0]);
424 else if (cmd->clean_on_exit)
425 mark_child_for_cleanup(cmd->pid);
426
427 /*
428 * Wait for child's execvp. If the execvp succeeds (or if fork()
429 * failed), EOF is seen immediately by the parent. Otherwise, the
430 * child process sends a single byte.
431 * Note that use of this infrastructure is completely advisory,
432 * therefore, we keep error checks minimal.
433 */
434 close(notify_pipe[1]);
435 if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
436 /*
437 * At this point we know that fork() succeeded, but execvp()
438 * failed. Errors have been reported to our stderr.
439 */
440 wait_or_whine(cmd->pid, cmd->argv[0], 0);
441 failed_errno = errno;
442 cmd->pid = -1;
443 }
444 close(notify_pipe[0]);
445 }
446 #else
447 {
448 int fhin = 0, fhout = 1, fherr = 2;
449 const char **sargv = cmd->argv;
450 struct argv_array nargv = ARGV_ARRAY_INIT;
451
452 if (cmd->no_stdin)
453 fhin = open("/dev/null", O_RDWR);
454 else if (need_in)
455 fhin = dup(fdin[0]);
456 else if (cmd->in)
457 fhin = dup(cmd->in);
458
459 if (cmd->no_stderr)
460 fherr = open("/dev/null", O_RDWR);
461 else if (need_err)
462 fherr = dup(fderr[1]);
463 else if (cmd->err > 2)
464 fherr = dup(cmd->err);
465
466 if (cmd->no_stdout)
467 fhout = open("/dev/null", O_RDWR);
468 else if (cmd->stdout_to_stderr)
469 fhout = dup(fherr);
470 else if (need_out)
471 fhout = dup(fdout[1]);
472 else if (cmd->out > 1)
473 fhout = dup(cmd->out);
474
475 if (cmd->git_cmd)
476 cmd->argv = prepare_git_cmd(&nargv, cmd->argv);
477 else if (cmd->use_shell)
478 cmd->argv = prepare_shell_cmd(&nargv, cmd->argv);
479
480 cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
481 cmd->dir, fhin, fhout, fherr);
482 failed_errno = errno;
483 if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
484 error_errno("cannot spawn %s", cmd->argv[0]);
485 if (cmd->clean_on_exit && cmd->pid >= 0)
486 mark_child_for_cleanup(cmd->pid);
487
488 argv_array_clear(&nargv);
489 cmd->argv = sargv;
490 if (fhin != 0)
491 close(fhin);
492 if (fhout != 1)
493 close(fhout);
494 if (fherr != 2)
495 close(fherr);
496 }
497 #endif
498
499 if (cmd->pid < 0) {
500 if (need_in)
501 close_pair(fdin);
502 else if (cmd->in)
503 close(cmd->in);
504 if (need_out)
505 close_pair(fdout);
506 else if (cmd->out)
507 close(cmd->out);
508 if (need_err)
509 close_pair(fderr);
510 else if (cmd->err)
511 close(cmd->err);
512 child_process_clear(cmd);
513 errno = failed_errno;
514 return -1;
515 }
516
517 if (need_in)
518 close(fdin[0]);
519 else if (cmd->in)
520 close(cmd->in);
521
522 if (need_out)
523 close(fdout[1]);
524 else if (cmd->out)
525 close(cmd->out);
526
527 if (need_err)
528 close(fderr[1]);
529 else if (cmd->err)
530 close(cmd->err);
531
532 return 0;
533 }
534
535 int finish_command(struct child_process *cmd)
536 {
537 int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
538 child_process_clear(cmd);
539 return ret;
540 }
541
542 int finish_command_in_signal(struct child_process *cmd)
543 {
544 return wait_or_whine(cmd->pid, cmd->argv[0], 1);
545 }
546
547
548 int run_command(struct child_process *cmd)
549 {
550 int code;
551
552 if (cmd->out < 0 || cmd->err < 0)
553 die("BUG: run_command with a pipe can cause deadlock");
554
555 code = start_command(cmd);
556 if (code)
557 return code;
558 return finish_command(cmd);
559 }
560
561 int run_command_v_opt(const char **argv, int opt)
562 {
563 return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
564 }
565
566 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
567 {
568 struct child_process cmd = CHILD_PROCESS_INIT;
569 cmd.argv = argv;
570 cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
571 cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
572 cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
573 cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
574 cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
575 cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
576 cmd.dir = dir;
577 cmd.env = env;
578 return run_command(&cmd);
579 }
580
581 #ifndef NO_PTHREADS
582 static pthread_t main_thread;
583 static int main_thread_set;
584 static pthread_key_t async_key;
585 static pthread_key_t async_die_counter;
586
587 static void *run_thread(void *data)
588 {
589 struct async *async = data;
590 intptr_t ret;
591
592 if (async->isolate_sigpipe) {
593 sigset_t mask;
594 sigemptyset(&mask);
595 sigaddset(&mask, SIGPIPE);
596 if (pthread_sigmask(SIG_BLOCK, &mask, NULL) < 0) {
597 ret = error("unable to block SIGPIPE in async thread");
598 return (void *)ret;
599 }
600 }
601
602 pthread_setspecific(async_key, async);
603 ret = async->proc(async->proc_in, async->proc_out, async->data);
604 return (void *)ret;
605 }
606
607 static NORETURN void die_async(const char *err, va_list params)
608 {
609 vreportf("fatal: ", err, params);
610
611 if (in_async()) {
612 struct async *async = pthread_getspecific(async_key);
613 if (async->proc_in >= 0)
614 close(async->proc_in);
615 if (async->proc_out >= 0)
616 close(async->proc_out);
617 pthread_exit((void *)128);
618 }
619
620 exit(128);
621 }
622
623 static int async_die_is_recursing(void)
624 {
625 void *ret = pthread_getspecific(async_die_counter);
626 pthread_setspecific(async_die_counter, (void *)1);
627 return ret != NULL;
628 }
629
630 int in_async(void)
631 {
632 if (!main_thread_set)
633 return 0; /* no asyncs started yet */
634 return !pthread_equal(main_thread, pthread_self());
635 }
636
637 void NORETURN async_exit(int code)
638 {
639 pthread_exit((void *)(intptr_t)code);
640 }
641
642 #else
643
644 static struct {
645 void (**handlers)(void);
646 size_t nr;
647 size_t alloc;
648 } git_atexit_hdlrs;
649
650 static int git_atexit_installed;
651
652 static void git_atexit_dispatch(void)
653 {
654 size_t i;
655
656 for (i=git_atexit_hdlrs.nr ; i ; i--)
657 git_atexit_hdlrs.handlers[i-1]();
658 }
659
660 static void git_atexit_clear(void)
661 {
662 free(git_atexit_hdlrs.handlers);
663 memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
664 git_atexit_installed = 0;
665 }
666
667 #undef atexit
668 int git_atexit(void (*handler)(void))
669 {
670 ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
671 git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
672 if (!git_atexit_installed) {
673 if (atexit(&git_atexit_dispatch))
674 return -1;
675 git_atexit_installed = 1;
676 }
677 return 0;
678 }
679 #define atexit git_atexit
680
681 static int process_is_async;
682 int in_async(void)
683 {
684 return process_is_async;
685 }
686
687 void NORETURN async_exit(int code)
688 {
689 exit(code);
690 }
691
692 #endif
693
694 int start_async(struct async *async)
695 {
696 int need_in, need_out;
697 int fdin[2], fdout[2];
698 int proc_in, proc_out;
699
700 need_in = async->in < 0;
701 if (need_in) {
702 if (pipe(fdin) < 0) {
703 if (async->out > 0)
704 close(async->out);
705 return error_errno("cannot create pipe");
706 }
707 async->in = fdin[1];
708 }
709
710 need_out = async->out < 0;
711 if (need_out) {
712 if (pipe(fdout) < 0) {
713 if (need_in)
714 close_pair(fdin);
715 else if (async->in)
716 close(async->in);
717 return error_errno("cannot create pipe");
718 }
719 async->out = fdout[0];
720 }
721
722 if (need_in)
723 proc_in = fdin[0];
724 else if (async->in)
725 proc_in = async->in;
726 else
727 proc_in = -1;
728
729 if (need_out)
730 proc_out = fdout[1];
731 else if (async->out)
732 proc_out = async->out;
733 else
734 proc_out = -1;
735
736 #ifdef NO_PTHREADS
737 /* Flush stdio before fork() to avoid cloning buffers */
738 fflush(NULL);
739
740 async->pid = fork();
741 if (async->pid < 0) {
742 error_errno("fork (async) failed");
743 goto error;
744 }
745 if (!async->pid) {
746 if (need_in)
747 close(fdin[1]);
748 if (need_out)
749 close(fdout[0]);
750 git_atexit_clear();
751 process_is_async = 1;
752 exit(!!async->proc(proc_in, proc_out, async->data));
753 }
754
755 mark_child_for_cleanup(async->pid);
756
757 if (need_in)
758 close(fdin[0]);
759 else if (async->in)
760 close(async->in);
761
762 if (need_out)
763 close(fdout[1]);
764 else if (async->out)
765 close(async->out);
766 #else
767 if (!main_thread_set) {
768 /*
769 * We assume that the first time that start_async is called
770 * it is from the main thread.
771 */
772 main_thread_set = 1;
773 main_thread = pthread_self();
774 pthread_key_create(&async_key, NULL);
775 pthread_key_create(&async_die_counter, NULL);
776 set_die_routine(die_async);
777 set_die_is_recursing_routine(async_die_is_recursing);
778 }
779
780 if (proc_in >= 0)
781 set_cloexec(proc_in);
782 if (proc_out >= 0)
783 set_cloexec(proc_out);
784 async->proc_in = proc_in;
785 async->proc_out = proc_out;
786 {
787 int err = pthread_create(&async->tid, NULL, run_thread, async);
788 if (err) {
789 error_errno("cannot create thread");
790 goto error;
791 }
792 }
793 #endif
794 return 0;
795
796 error:
797 if (need_in)
798 close_pair(fdin);
799 else if (async->in)
800 close(async->in);
801
802 if (need_out)
803 close_pair(fdout);
804 else if (async->out)
805 close(async->out);
806 return -1;
807 }
808
809 int finish_async(struct async *async)
810 {
811 #ifdef NO_PTHREADS
812 return wait_or_whine(async->pid, "child process", 0);
813 #else
814 void *ret = (void *)(intptr_t)(-1);
815
816 if (pthread_join(async->tid, &ret))
817 error("pthread_join failed");
818 return (int)(intptr_t)ret;
819 #endif
820 }
821
822 const char *find_hook(const char *name)
823 {
824 static struct strbuf path = STRBUF_INIT;
825
826 strbuf_reset(&path);
827 if (git_hooks_path)
828 strbuf_addf(&path, "%s/%s", git_hooks_path, name);
829 else
830 strbuf_git_path(&path, "hooks/%s", name);
831 if (access(path.buf, X_OK) < 0)
832 return NULL;
833 return path.buf;
834 }
835
836 int run_hook_ve(const char *const *env, const char *name, va_list args)
837 {
838 struct child_process hook = CHILD_PROCESS_INIT;
839 const char *p;
840
841 p = find_hook(name);
842 if (!p)
843 return 0;
844
845 argv_array_push(&hook.args, p);
846 while ((p = va_arg(args, const char *)))
847 argv_array_push(&hook.args, p);
848 hook.env = env;
849 hook.no_stdin = 1;
850 hook.stdout_to_stderr = 1;
851
852 return run_command(&hook);
853 }
854
855 int run_hook_le(const char *const *env, const char *name, ...)
856 {
857 va_list args;
858 int ret;
859
860 va_start(args, name);
861 ret = run_hook_ve(env, name, args);
862 va_end(args);
863
864 return ret;
865 }
866
867 struct io_pump {
868 /* initialized by caller */
869 int fd;
870 int type; /* POLLOUT or POLLIN */
871 union {
872 struct {
873 const char *buf;
874 size_t len;
875 } out;
876 struct {
877 struct strbuf *buf;
878 size_t hint;
879 } in;
880 } u;
881
882 /* returned by pump_io */
883 int error; /* 0 for success, otherwise errno */
884
885 /* internal use */
886 struct pollfd *pfd;
887 };
888
889 static int pump_io_round(struct io_pump *slots, int nr, struct pollfd *pfd)
890 {
891 int pollsize = 0;
892 int i;
893
894 for (i = 0; i < nr; i++) {
895 struct io_pump *io = &slots[i];
896 if (io->fd < 0)
897 continue;
898 pfd[pollsize].fd = io->fd;
899 pfd[pollsize].events = io->type;
900 io->pfd = &pfd[pollsize++];
901 }
902
903 if (!pollsize)
904 return 0;
905
906 if (poll(pfd, pollsize, -1) < 0) {
907 if (errno == EINTR)
908 return 1;
909 die_errno("poll failed");
910 }
911
912 for (i = 0; i < nr; i++) {
913 struct io_pump *io = &slots[i];
914
915 if (io->fd < 0)
916 continue;
917
918 if (!(io->pfd->revents & (POLLOUT|POLLIN|POLLHUP|POLLERR|POLLNVAL)))
919 continue;
920
921 if (io->type == POLLOUT) {
922 ssize_t len = xwrite(io->fd,
923 io->u.out.buf, io->u.out.len);
924 if (len < 0) {
925 io->error = errno;
926 close(io->fd);
927 io->fd = -1;
928 } else {
929 io->u.out.buf += len;
930 io->u.out.len -= len;
931 if (!io->u.out.len) {
932 close(io->fd);
933 io->fd = -1;
934 }
935 }
936 }
937
938 if (io->type == POLLIN) {
939 ssize_t len = strbuf_read_once(io->u.in.buf,
940 io->fd, io->u.in.hint);
941 if (len < 0)
942 io->error = errno;
943 if (len <= 0) {
944 close(io->fd);
945 io->fd = -1;
946 }
947 }
948 }
949
950 return 1;
951 }
952
953 static int pump_io(struct io_pump *slots, int nr)
954 {
955 struct pollfd *pfd;
956 int i;
957
958 for (i = 0; i < nr; i++)
959 slots[i].error = 0;
960
961 ALLOC_ARRAY(pfd, nr);
962 while (pump_io_round(slots, nr, pfd))
963 ; /* nothing */
964 free(pfd);
965
966 /* There may be multiple errno values, so just pick the first. */
967 for (i = 0; i < nr; i++) {
968 if (slots[i].error) {
969 errno = slots[i].error;
970 return -1;
971 }
972 }
973 return 0;
974 }
975
976
977 int pipe_command(struct child_process *cmd,
978 const char *in, size_t in_len,
979 struct strbuf *out, size_t out_hint,
980 struct strbuf *err, size_t err_hint)
981 {
982 struct io_pump io[3];
983 int nr = 0;
984
985 if (in)
986 cmd->in = -1;
987 if (out)
988 cmd->out = -1;
989 if (err)
990 cmd->err = -1;
991
992 if (start_command(cmd) < 0)
993 return -1;
994
995 if (in) {
996 io[nr].fd = cmd->in;
997 io[nr].type = POLLOUT;
998 io[nr].u.out.buf = in;
999 io[nr].u.out.len = in_len;
1000 nr++;
1001 }
1002 if (out) {
1003 io[nr].fd = cmd->out;
1004 io[nr].type = POLLIN;
1005 io[nr].u.in.buf = out;
1006 io[nr].u.in.hint = out_hint;
1007 nr++;
1008 }
1009 if (err) {
1010 io[nr].fd = cmd->err;
1011 io[nr].type = POLLIN;
1012 io[nr].u.in.buf = err;
1013 io[nr].u.in.hint = err_hint;
1014 nr++;
1015 }
1016
1017 if (pump_io(io, nr) < 0) {
1018 finish_command(cmd); /* throw away exit code */
1019 return -1;
1020 }
1021
1022 return finish_command(cmd);
1023 }
1024
1025 enum child_state {
1026 GIT_CP_FREE,
1027 GIT_CP_WORKING,
1028 GIT_CP_WAIT_CLEANUP,
1029 };
1030
1031 struct parallel_processes {
1032 void *data;
1033
1034 int max_processes;
1035 int nr_processes;
1036
1037 get_next_task_fn get_next_task;
1038 start_failure_fn start_failure;
1039 task_finished_fn task_finished;
1040
1041 struct {
1042 enum child_state state;
1043 struct child_process process;
1044 struct strbuf err;
1045 void *data;
1046 } *children;
1047 /*
1048 * The struct pollfd is logically part of *children,
1049 * but the system call expects it as its own array.
1050 */
1051 struct pollfd *pfd;
1052
1053 unsigned shutdown : 1;
1054
1055 int output_owner;
1056 struct strbuf buffered_output; /* of finished children */
1057 };
1058
1059 static int default_start_failure(struct strbuf *out,
1060 void *pp_cb,
1061 void *pp_task_cb)
1062 {
1063 return 0;
1064 }
1065
1066 static int default_task_finished(int result,
1067 struct strbuf *out,
1068 void *pp_cb,
1069 void *pp_task_cb)
1070 {
1071 return 0;
1072 }
1073
1074 static void kill_children(struct parallel_processes *pp, int signo)
1075 {
1076 int i, n = pp->max_processes;
1077
1078 for (i = 0; i < n; i++)
1079 if (pp->children[i].state == GIT_CP_WORKING)
1080 kill(pp->children[i].process.pid, signo);
1081 }
1082
1083 static struct parallel_processes *pp_for_signal;
1084
1085 static void handle_children_on_signal(int signo)
1086 {
1087 kill_children(pp_for_signal, signo);
1088 sigchain_pop(signo);
1089 raise(signo);
1090 }
1091
1092 static void pp_init(struct parallel_processes *pp,
1093 int n,
1094 get_next_task_fn get_next_task,
1095 start_failure_fn start_failure,
1096 task_finished_fn task_finished,
1097 void *data)
1098 {
1099 int i;
1100
1101 if (n < 1)
1102 n = online_cpus();
1103
1104 pp->max_processes = n;
1105
1106 trace_printf("run_processes_parallel: preparing to run up to %d tasks", n);
1107
1108 pp->data = data;
1109 if (!get_next_task)
1110 die("BUG: you need to specify a get_next_task function");
1111 pp->get_next_task = get_next_task;
1112
1113 pp->start_failure = start_failure ? start_failure : default_start_failure;
1114 pp->task_finished = task_finished ? task_finished : default_task_finished;
1115
1116 pp->nr_processes = 0;
1117 pp->output_owner = 0;
1118 pp->shutdown = 0;
1119 pp->children = xcalloc(n, sizeof(*pp->children));
1120 pp->pfd = xcalloc(n, sizeof(*pp->pfd));
1121 strbuf_init(&pp->buffered_output, 0);
1122
1123 for (i = 0; i < n; i++) {
1124 strbuf_init(&pp->children[i].err, 0);
1125 child_process_init(&pp->children[i].process);
1126 pp->pfd[i].events = POLLIN | POLLHUP;
1127 pp->pfd[i].fd = -1;
1128 }
1129
1130 pp_for_signal = pp;
1131 sigchain_push_common(handle_children_on_signal);
1132 }
1133
1134 static void pp_cleanup(struct parallel_processes *pp)
1135 {
1136 int i;
1137
1138 trace_printf("run_processes_parallel: done");
1139 for (i = 0; i < pp->max_processes; i++) {
1140 strbuf_release(&pp->children[i].err);
1141 child_process_clear(&pp->children[i].process);
1142 }
1143
1144 free(pp->children);
1145 free(pp->pfd);
1146
1147 /*
1148 * When get_next_task added messages to the buffer in its last
1149 * iteration, the buffered output is non empty.
1150 */
1151 strbuf_write(&pp->buffered_output, stderr);
1152 strbuf_release(&pp->buffered_output);
1153
1154 sigchain_pop_common();
1155 }
1156
1157 /* returns
1158 * 0 if a new task was started.
1159 * 1 if no new jobs was started (get_next_task ran out of work, non critical
1160 * problem with starting a new command)
1161 * <0 no new job was started, user wishes to shutdown early. Use negative code
1162 * to signal the children.
1163 */
1164 static int pp_start_one(struct parallel_processes *pp)
1165 {
1166 int i, code;
1167
1168 for (i = 0; i < pp->max_processes; i++)
1169 if (pp->children[i].state == GIT_CP_FREE)
1170 break;
1171 if (i == pp->max_processes)
1172 die("BUG: bookkeeping is hard");
1173
1174 code = pp->get_next_task(&pp->children[i].process,
1175 &pp->children[i].err,
1176 pp->data,
1177 &pp->children[i].data);
1178 if (!code) {
1179 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1180 strbuf_reset(&pp->children[i].err);
1181 return 1;
1182 }
1183 pp->children[i].process.err = -1;
1184 pp->children[i].process.stdout_to_stderr = 1;
1185 pp->children[i].process.no_stdin = 1;
1186
1187 if (start_command(&pp->children[i].process)) {
1188 code = pp->start_failure(&pp->children[i].err,
1189 pp->data,
1190 &pp->children[i].data);
1191 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1192 strbuf_reset(&pp->children[i].err);
1193 if (code)
1194 pp->shutdown = 1;
1195 return code;
1196 }
1197
1198 pp->nr_processes++;
1199 pp->children[i].state = GIT_CP_WORKING;
1200 pp->pfd[i].fd = pp->children[i].process.err;
1201 return 0;
1202 }
1203
1204 static void pp_buffer_stderr(struct parallel_processes *pp, int output_timeout)
1205 {
1206 int i;
1207
1208 while ((i = poll(pp->pfd, pp->max_processes, output_timeout)) < 0) {
1209 if (errno == EINTR)
1210 continue;
1211 pp_cleanup(pp);
1212 die_errno("poll");
1213 }
1214
1215 /* Buffer output from all pipes. */
1216 for (i = 0; i < pp->max_processes; i++) {
1217 if (pp->children[i].state == GIT_CP_WORKING &&
1218 pp->pfd[i].revents & (POLLIN | POLLHUP)) {
1219 int n = strbuf_read_once(&pp->children[i].err,
1220 pp->children[i].process.err, 0);
1221 if (n == 0) {
1222 close(pp->children[i].process.err);
1223 pp->children[i].state = GIT_CP_WAIT_CLEANUP;
1224 } else if (n < 0)
1225 if (errno != EAGAIN)
1226 die_errno("read");
1227 }
1228 }
1229 }
1230
1231 static void pp_output(struct parallel_processes *pp)
1232 {
1233 int i = pp->output_owner;
1234 if (pp->children[i].state == GIT_CP_WORKING &&
1235 pp->children[i].err.len) {
1236 strbuf_write(&pp->children[i].err, stderr);
1237 strbuf_reset(&pp->children[i].err);
1238 }
1239 }
1240
1241 static int pp_collect_finished(struct parallel_processes *pp)
1242 {
1243 int i, code;
1244 int n = pp->max_processes;
1245 int result = 0;
1246
1247 while (pp->nr_processes > 0) {
1248 for (i = 0; i < pp->max_processes; i++)
1249 if (pp->children[i].state == GIT_CP_WAIT_CLEANUP)
1250 break;
1251 if (i == pp->max_processes)
1252 break;
1253
1254 code = finish_command(&pp->children[i].process);
1255
1256 code = pp->task_finished(code,
1257 &pp->children[i].err, pp->data,
1258 &pp->children[i].data);
1259
1260 if (code)
1261 result = code;
1262 if (code < 0)
1263 break;
1264
1265 pp->nr_processes--;
1266 pp->children[i].state = GIT_CP_FREE;
1267 pp->pfd[i].fd = -1;
1268 child_process_init(&pp->children[i].process);
1269
1270 if (i != pp->output_owner) {
1271 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1272 strbuf_reset(&pp->children[i].err);
1273 } else {
1274 strbuf_write(&pp->children[i].err, stderr);
1275 strbuf_reset(&pp->children[i].err);
1276
1277 /* Output all other finished child processes */
1278 strbuf_write(&pp->buffered_output, stderr);
1279 strbuf_reset(&pp->buffered_output);
1280
1281 /*
1282 * Pick next process to output live.
1283 * NEEDSWORK:
1284 * For now we pick it randomly by doing a round
1285 * robin. Later we may want to pick the one with
1286 * the most output or the longest or shortest
1287 * running process time.
1288 */
1289 for (i = 0; i < n; i++)
1290 if (pp->children[(pp->output_owner + i) % n].state == GIT_CP_WORKING)
1291 break;
1292 pp->output_owner = (pp->output_owner + i) % n;
1293 }
1294 }
1295 return result;
1296 }
1297
1298 int run_processes_parallel(int n,
1299 get_next_task_fn get_next_task,
1300 start_failure_fn start_failure,
1301 task_finished_fn task_finished,
1302 void *pp_cb)
1303 {
1304 int i, code;
1305 int output_timeout = 100;
1306 int spawn_cap = 4;
1307 struct parallel_processes pp;
1308
1309 pp_init(&pp, n, get_next_task, start_failure, task_finished, pp_cb);
1310 while (1) {
1311 for (i = 0;
1312 i < spawn_cap && !pp.shutdown &&
1313 pp.nr_processes < pp.max_processes;
1314 i++) {
1315 code = pp_start_one(&pp);
1316 if (!code)
1317 continue;
1318 if (code < 0) {
1319 pp.shutdown = 1;
1320 kill_children(&pp, -code);
1321 }
1322 break;
1323 }
1324 if (!pp.nr_processes)
1325 break;
1326 pp_buffer_stderr(&pp, output_timeout);
1327 pp_output(&pp);
1328 code = pp_collect_finished(&pp);
1329 if (code) {
1330 pp.shutdown = 1;
1331 if (code < 0)
1332 kill_children(&pp, -code);
1333 }
1334 }
1335
1336 pp_cleanup(&pp);
1337 return 0;
1338 }
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