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Merge branch 'sb/submodule-embed-gitdir'
[alt-git.git] / run-command.c
blob73bfba7ef94e678afa830550199f14b6f5ca5ad0
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_process *process;
25 struct child_to_clean *next;
26 };
27 static struct child_to_clean *children_to_clean;
28 static int installed_child_cleanup_handler;
29
30 static void cleanup_children(int sig, int in_signal)
31 {
32 struct child_to_clean *children_to_wait_for = NULL;
33
34 while (children_to_clean) {
35 struct child_to_clean *p = children_to_clean;
36 children_to_clean = p->next;
37
38 if (p->process && !in_signal) {
39 struct child_process *process = p->process;
40 if (process->clean_on_exit_handler) {
41 trace_printf(
42 "trace: run_command: running exit handler for pid %"
43 PRIuMAX, (uintmax_t)p->pid
44 );
45 process->clean_on_exit_handler(process);
46 }
47 }
48
49 kill(p->pid, sig);
50
51 if (p->process->wait_after_clean) {
52 p->next = children_to_wait_for;
53 children_to_wait_for = p;
54 } else {
55 if (!in_signal)
56 free(p);
57 }
58 }
59
60 while (children_to_wait_for) {
61 struct child_to_clean *p = children_to_wait_for;
62 children_to_wait_for = p->next;
63
64 while (waitpid(p->pid, NULL, 0) < 0 && errno == EINTR)
65 ; /* spin waiting for process exit or error */
66
67 if (!in_signal)
68 free(p);
69 }
70 }
71
72 static void cleanup_children_on_signal(int sig)
73 {
74 cleanup_children(sig, 1);
75 sigchain_pop(sig);
76 raise(sig);
77 }
78
79 static void cleanup_children_on_exit(void)
80 {
81 cleanup_children(SIGTERM, 0);
82 }
83
84 static void mark_child_for_cleanup(pid_t pid, struct child_process *process)
85 {
86 struct child_to_clean *p = xmalloc(sizeof(*p));
87 p->pid = pid;
88 p->process = process;
89 p->next = children_to_clean;
90 children_to_clean = p;
91
92 if (!installed_child_cleanup_handler) {
93 atexit(cleanup_children_on_exit);
94 sigchain_push_common(cleanup_children_on_signal);
95 installed_child_cleanup_handler = 1;
96 }
97 }
98
99 static void clear_child_for_cleanup(pid_t pid)
100 {
101 struct child_to_clean **pp;
102
103 for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
104 struct child_to_clean *clean_me = *pp;
105
106 if (clean_me->pid == pid) {
107 *pp = clean_me->next;
108 free(clean_me);
109 return;
110 }
111 }
112 }
113
114 static inline void close_pair(int fd[2])
115 {
116 close(fd[0]);
117 close(fd[1]);
118 }
119
120 #ifndef GIT_WINDOWS_NATIVE
121 static inline void dup_devnull(int to)
122 {
123 int fd = open("/dev/null", O_RDWR);
124 if (fd < 0)
125 die_errno(_("open /dev/null failed"));
126 if (dup2(fd, to) < 0)
127 die_errno(_("dup2(%d,%d) failed"), fd, to);
128 close(fd);
129 }
130 #endif
131
132 static char *locate_in_PATH(const char *file)
133 {
134 const char *p = getenv("PATH");
135 struct strbuf buf = STRBUF_INIT;
136
137 if (!p || !*p)
138 return NULL;
139
140 while (1) {
141 const char *end = strchrnul(p, ':');
142
143 strbuf_reset(&buf);
144
145 /* POSIX specifies an empty entry as the current directory. */
146 if (end != p) {
147 strbuf_add(&buf, p, end - p);
148 strbuf_addch(&buf, '/');
149 }
150 strbuf_addstr(&buf, file);
151
152 if (!access(buf.buf, F_OK))
153 return strbuf_detach(&buf, NULL);
154
155 if (!*end)
156 break;
157 p = end + 1;
158 }
159
160 strbuf_release(&buf);
161 return NULL;
162 }
163
164 static int exists_in_PATH(const char *file)
165 {
166 char *r = locate_in_PATH(file);
167 free(r);
168 return r != NULL;
169 }
170
171 int sane_execvp(const char *file, char * const argv[])
172 {
173 if (!execvp(file, argv))
174 return 0; /* cannot happen ;-) */
175
176 /*
177 * When a command can't be found because one of the directories
178 * listed in $PATH is unsearchable, execvp reports EACCES, but
179 * careful usability testing (read: analysis of occasional bug
180 * reports) reveals that "No such file or directory" is more
181 * intuitive.
182 *
183 * We avoid commands with "/", because execvp will not do $PATH
184 * lookups in that case.
185 *
186 * The reassignment of EACCES to errno looks like a no-op below,
187 * but we need to protect against exists_in_PATH overwriting errno.
188 */
189 if (errno == EACCES && !strchr(file, '/'))
190 errno = exists_in_PATH(file) ? EACCES : ENOENT;
191 else if (errno == ENOTDIR && !strchr(file, '/'))
192 errno = ENOENT;
193 return -1;
194 }
195
196 static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
197 {
198 if (!argv[0])
199 die("BUG: shell command is empty");
200
201 if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
202 #ifndef GIT_WINDOWS_NATIVE
203 argv_array_push(out, SHELL_PATH);
204 #else
205 argv_array_push(out, "sh");
206 #endif
207 argv_array_push(out, "-c");
208
209 /*
210 * If we have no extra arguments, we do not even need to
211 * bother with the "$@" magic.
212 */
213 if (!argv[1])
214 argv_array_push(out, argv[0]);
215 else
216 argv_array_pushf(out, "%s \"$@\"", argv[0]);
217 }
218
219 argv_array_pushv(out, argv);
220 return out->argv;
221 }
222
223 #ifndef GIT_WINDOWS_NATIVE
224 static int execv_shell_cmd(const char **argv)
225 {
226 struct argv_array nargv = ARGV_ARRAY_INIT;
227 prepare_shell_cmd(&nargv, argv);
228 trace_argv_printf(nargv.argv, "trace: exec:");
229 sane_execvp(nargv.argv[0], (char **)nargv.argv);
230 argv_array_clear(&nargv);
231 return -1;
232 }
233 #endif
234
235 #ifndef GIT_WINDOWS_NATIVE
236 static int child_notifier = -1;
237
238 static void notify_parent(void)
239 {
240 /*
241 * execvp failed. If possible, we'd like to let start_command
242 * know, so failures like ENOENT can be handled right away; but
243 * otherwise, finish_command will still report the error.
244 */
245 xwrite(child_notifier, "", 1);
246 }
247 #endif
248
249 static inline void set_cloexec(int fd)
250 {
251 int flags = fcntl(fd, F_GETFD);
252 if (flags >= 0)
253 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
254 }
255
256 static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
257 {
258 int status, code = -1;
259 pid_t waiting;
260 int failed_errno = 0;
261
262 while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
263 ; /* nothing */
264 if (in_signal)
265 return 0;
266
267 if (waiting < 0) {
268 failed_errno = errno;
269 error_errno("waitpid for %s failed", argv0);
270 } else if (waiting != pid) {
271 error("waitpid is confused (%s)", argv0);
272 } else if (WIFSIGNALED(status)) {
273 code = WTERMSIG(status);
274 if (code != SIGINT && code != SIGQUIT && code != SIGPIPE)
275 error("%s died of signal %d", argv0, code);
276 /*
277 * This return value is chosen so that code & 0xff
278 * mimics the exit code that a POSIX shell would report for
279 * a program that died from this signal.
280 */
281 code += 128;
282 } else if (WIFEXITED(status)) {
283 code = WEXITSTATUS(status);
284 /*
285 * Convert special exit code when execvp failed.
286 */
287 if (code == 127) {
288 code = -1;
289 failed_errno = ENOENT;
290 }
291 } else {
292 error("waitpid is confused (%s)", argv0);
293 }
294
295 clear_child_for_cleanup(pid);
296
297 errno = failed_errno;
298 return code;
299 }
300
301 int start_command(struct child_process *cmd)
302 {
303 int need_in, need_out, need_err;
304 int fdin[2], fdout[2], fderr[2];
305 int failed_errno;
306 char *str;
307
308 if (!cmd->argv)
309 cmd->argv = cmd->args.argv;
310 if (!cmd->env)
311 cmd->env = cmd->env_array.argv;
312
313 /*
314 * In case of errors we must keep the promise to close FDs
315 * that have been passed in via ->in and ->out.
316 */
317
318 need_in = !cmd->no_stdin && cmd->in < 0;
319 if (need_in) {
320 if (pipe(fdin) < 0) {
321 failed_errno = errno;
322 if (cmd->out > 0)
323 close(cmd->out);
324 str = "standard input";
325 goto fail_pipe;
326 }
327 cmd->in = fdin[1];
328 }
329
330 need_out = !cmd->no_stdout
331 && !cmd->stdout_to_stderr
332 && cmd->out < 0;
333 if (need_out) {
334 if (pipe(fdout) < 0) {
335 failed_errno = errno;
336 if (need_in)
337 close_pair(fdin);
338 else if (cmd->in)
339 close(cmd->in);
340 str = "standard output";
341 goto fail_pipe;
342 }
343 cmd->out = fdout[0];
344 }
345
346 need_err = !cmd->no_stderr && cmd->err < 0;
347 if (need_err) {
348 if (pipe(fderr) < 0) {
349 failed_errno = errno;
350 if (need_in)
351 close_pair(fdin);
352 else if (cmd->in)
353 close(cmd->in);
354 if (need_out)
355 close_pair(fdout);
356 else if (cmd->out)
357 close(cmd->out);
358 str = "standard error";
359 fail_pipe:
360 error("cannot create %s pipe for %s: %s",
361 str, cmd->argv[0], strerror(failed_errno));
362 child_process_clear(cmd);
363 errno = failed_errno;
364 return -1;
365 }
366 cmd->err = fderr[0];
367 }
368
369 trace_argv_printf(cmd->argv, "trace: run_command:");
370 fflush(NULL);
371
372 #ifndef GIT_WINDOWS_NATIVE
373 {
374 int notify_pipe[2];
375 if (pipe(notify_pipe))
376 notify_pipe[0] = notify_pipe[1] = -1;
377
378 cmd->pid = fork();
379 failed_errno = errno;
380 if (!cmd->pid) {
381 /*
382 * Redirect the channel to write syscall error messages to
383 * before redirecting the process's stderr so that all die()
384 * in subsequent call paths use the parent's stderr.
385 */
386 if (cmd->no_stderr || need_err) {
387 int child_err = dup(2);
388 set_cloexec(child_err);
389 set_error_handle(fdopen(child_err, "w"));
390 }
391
392 close(notify_pipe[0]);
393 set_cloexec(notify_pipe[1]);
394 child_notifier = notify_pipe[1];
395 atexit(notify_parent);
396
397 if (cmd->no_stdin)
398 dup_devnull(0);
399 else if (need_in) {
400 dup2(fdin[0], 0);
401 close_pair(fdin);
402 } else if (cmd->in) {
403 dup2(cmd->in, 0);
404 close(cmd->in);
405 }
406
407 if (cmd->no_stderr)
408 dup_devnull(2);
409 else if (need_err) {
410 dup2(fderr[1], 2);
411 close_pair(fderr);
412 } else if (cmd->err > 1) {
413 dup2(cmd->err, 2);
414 close(cmd->err);
415 }
416
417 if (cmd->no_stdout)
418 dup_devnull(1);
419 else if (cmd->stdout_to_stderr)
420 dup2(2, 1);
421 else if (need_out) {
422 dup2(fdout[1], 1);
423 close_pair(fdout);
424 } else if (cmd->out > 1) {
425 dup2(cmd->out, 1);
426 close(cmd->out);
427 }
428
429 if (cmd->dir && chdir(cmd->dir))
430 die_errno("exec '%s': cd to '%s' failed", cmd->argv[0],
431 cmd->dir);
432 if (cmd->env) {
433 for (; *cmd->env; cmd->env++) {
434 if (strchr(*cmd->env, '='))
435 putenv((char *)*cmd->env);
436 else
437 unsetenv(*cmd->env);
438 }
439 }
440 if (cmd->git_cmd)
441 execv_git_cmd(cmd->argv);
442 else if (cmd->use_shell)
443 execv_shell_cmd(cmd->argv);
444 else
445 sane_execvp(cmd->argv[0], (char *const*) cmd->argv);
446 if (errno == ENOENT) {
447 if (!cmd->silent_exec_failure)
448 error("cannot run %s: %s", cmd->argv[0],
449 strerror(ENOENT));
450 exit(127);
451 } else {
452 die_errno("cannot exec '%s'", cmd->argv[0]);
453 }
454 }
455 if (cmd->pid < 0)
456 error_errno("cannot fork() for %s", cmd->argv[0]);
457 else if (cmd->clean_on_exit)
458 mark_child_for_cleanup(cmd->pid, cmd);
459
460 /*
461 * Wait for child's execvp. If the execvp succeeds (or if fork()
462 * failed), EOF is seen immediately by the parent. Otherwise, the
463 * child process sends a single byte.
464 * Note that use of this infrastructure is completely advisory,
465 * therefore, we keep error checks minimal.
466 */
467 close(notify_pipe[1]);
468 if (read(notify_pipe[0], &notify_pipe[1], 1) == 1) {
469 /*
470 * At this point we know that fork() succeeded, but execvp()
471 * failed. Errors have been reported to our stderr.
472 */
473 wait_or_whine(cmd->pid, cmd->argv[0], 0);
474 failed_errno = errno;
475 cmd->pid = -1;
476 }
477 close(notify_pipe[0]);
478 }
479 #else
480 {
481 int fhin = 0, fhout = 1, fherr = 2;
482 const char **sargv = cmd->argv;
483 struct argv_array nargv = ARGV_ARRAY_INIT;
484
485 if (cmd->no_stdin)
486 fhin = open("/dev/null", O_RDWR);
487 else if (need_in)
488 fhin = dup(fdin[0]);
489 else if (cmd->in)
490 fhin = dup(cmd->in);
491
492 if (cmd->no_stderr)
493 fherr = open("/dev/null", O_RDWR);
494 else if (need_err)
495 fherr = dup(fderr[1]);
496 else if (cmd->err > 2)
497 fherr = dup(cmd->err);
498
499 if (cmd->no_stdout)
500 fhout = open("/dev/null", O_RDWR);
501 else if (cmd->stdout_to_stderr)
502 fhout = dup(fherr);
503 else if (need_out)
504 fhout = dup(fdout[1]);
505 else if (cmd->out > 1)
506 fhout = dup(cmd->out);
507
508 if (cmd->git_cmd)
509 cmd->argv = prepare_git_cmd(&nargv, cmd->argv);
510 else if (cmd->use_shell)
511 cmd->argv = prepare_shell_cmd(&nargv, cmd->argv);
512
513 cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
514 cmd->dir, fhin, fhout, fherr);
515 failed_errno = errno;
516 if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
517 error_errno("cannot spawn %s", cmd->argv[0]);
518 if (cmd->clean_on_exit && cmd->pid >= 0)
519 mark_child_for_cleanup(cmd->pid, cmd);
520
521 argv_array_clear(&nargv);
522 cmd->argv = sargv;
523 if (fhin != 0)
524 close(fhin);
525 if (fhout != 1)
526 close(fhout);
527 if (fherr != 2)
528 close(fherr);
529 }
530 #endif
531
532 if (cmd->pid < 0) {
533 if (need_in)
534 close_pair(fdin);
535 else if (cmd->in)
536 close(cmd->in);
537 if (need_out)
538 close_pair(fdout);
539 else if (cmd->out)
540 close(cmd->out);
541 if (need_err)
542 close_pair(fderr);
543 else if (cmd->err)
544 close(cmd->err);
545 child_process_clear(cmd);
546 errno = failed_errno;
547 return -1;
548 }
549
550 if (need_in)
551 close(fdin[0]);
552 else if (cmd->in)
553 close(cmd->in);
554
555 if (need_out)
556 close(fdout[1]);
557 else if (cmd->out)
558 close(cmd->out);
559
560 if (need_err)
561 close(fderr[1]);
562 else if (cmd->err)
563 close(cmd->err);
564
565 return 0;
566 }
567
568 int finish_command(struct child_process *cmd)
569 {
570 int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
571 child_process_clear(cmd);
572 return ret;
573 }
574
575 int finish_command_in_signal(struct child_process *cmd)
576 {
577 return wait_or_whine(cmd->pid, cmd->argv[0], 1);
578 }
579
580
581 int run_command(struct child_process *cmd)
582 {
583 int code;
584
585 if (cmd->out < 0 || cmd->err < 0)
586 die("BUG: run_command with a pipe can cause deadlock");
587
588 code = start_command(cmd);
589 if (code)
590 return code;
591 return finish_command(cmd);
592 }
593
594 int run_command_v_opt(const char **argv, int opt)
595 {
596 return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
597 }
598
599 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
600 {
601 struct child_process cmd = CHILD_PROCESS_INIT;
602 cmd.argv = argv;
603 cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
604 cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
605 cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
606 cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
607 cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
608 cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
609 cmd.dir = dir;
610 cmd.env = env;
611 return run_command(&cmd);
612 }
613
614 #ifndef NO_PTHREADS
615 static pthread_t main_thread;
616 static int main_thread_set;
617 static pthread_key_t async_key;
618 static pthread_key_t async_die_counter;
619
620 static void *run_thread(void *data)
621 {
622 struct async *async = data;
623 intptr_t ret;
624
625 if (async->isolate_sigpipe) {
626 sigset_t mask;
627 sigemptyset(&mask);
628 sigaddset(&mask, SIGPIPE);
629 if (pthread_sigmask(SIG_BLOCK, &mask, NULL) < 0) {
630 ret = error("unable to block SIGPIPE in async thread");
631 return (void *)ret;
632 }
633 }
634
635 pthread_setspecific(async_key, async);
636 ret = async->proc(async->proc_in, async->proc_out, async->data);
637 return (void *)ret;
638 }
639
640 static NORETURN void die_async(const char *err, va_list params)
641 {
642 vreportf("fatal: ", err, params);
643
644 if (in_async()) {
645 struct async *async = pthread_getspecific(async_key);
646 if (async->proc_in >= 0)
647 close(async->proc_in);
648 if (async->proc_out >= 0)
649 close(async->proc_out);
650 pthread_exit((void *)128);
651 }
652
653 exit(128);
654 }
655
656 static int async_die_is_recursing(void)
657 {
658 void *ret = pthread_getspecific(async_die_counter);
659 pthread_setspecific(async_die_counter, (void *)1);
660 return ret != NULL;
661 }
662
663 int in_async(void)
664 {
665 if (!main_thread_set)
666 return 0; /* no asyncs started yet */
667 return !pthread_equal(main_thread, pthread_self());
668 }
669
670 static void NORETURN async_exit(int code)
671 {
672 pthread_exit((void *)(intptr_t)code);
673 }
674
675 #else
676
677 static struct {
678 void (**handlers)(void);
679 size_t nr;
680 size_t alloc;
681 } git_atexit_hdlrs;
682
683 static int git_atexit_installed;
684
685 static void git_atexit_dispatch(void)
686 {
687 size_t i;
688
689 for (i=git_atexit_hdlrs.nr ; i ; i--)
690 git_atexit_hdlrs.handlers[i-1]();
691 }
692
693 static void git_atexit_clear(void)
694 {
695 free(git_atexit_hdlrs.handlers);
696 memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
697 git_atexit_installed = 0;
698 }
699
700 #undef atexit
701 int git_atexit(void (*handler)(void))
702 {
703 ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
704 git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
705 if (!git_atexit_installed) {
706 if (atexit(&git_atexit_dispatch))
707 return -1;
708 git_atexit_installed = 1;
709 }
710 return 0;
711 }
712 #define atexit git_atexit
713
714 static int process_is_async;
715 int in_async(void)
716 {
717 return process_is_async;
718 }
719
720 static void NORETURN async_exit(int code)
721 {
722 exit(code);
723 }
724
725 #endif
726
727 void check_pipe(int err)
728 {
729 if (err == EPIPE) {
730 if (in_async())
731 async_exit(141);
732
733 signal(SIGPIPE, SIG_DFL);
734 raise(SIGPIPE);
735 /* Should never happen, but just in case... */
736 exit(141);
737 }
738 }
739
740 int start_async(struct async *async)
741 {
742 int need_in, need_out;
743 int fdin[2], fdout[2];
744 int proc_in, proc_out;
745
746 need_in = async->in < 0;
747 if (need_in) {
748 if (pipe(fdin) < 0) {
749 if (async->out > 0)
750 close(async->out);
751 return error_errno("cannot create pipe");
752 }
753 async->in = fdin[1];
754 }
755
756 need_out = async->out < 0;
757 if (need_out) {
758 if (pipe(fdout) < 0) {
759 if (need_in)
760 close_pair(fdin);
761 else if (async->in)
762 close(async->in);
763 return error_errno("cannot create pipe");
764 }
765 async->out = fdout[0];
766 }
767
768 if (need_in)
769 proc_in = fdin[0];
770 else if (async->in)
771 proc_in = async->in;
772 else
773 proc_in = -1;
774
775 if (need_out)
776 proc_out = fdout[1];
777 else if (async->out)
778 proc_out = async->out;
779 else
780 proc_out = -1;
781
782 #ifdef NO_PTHREADS
783 /* Flush stdio before fork() to avoid cloning buffers */
784 fflush(NULL);
785
786 async->pid = fork();
787 if (async->pid < 0) {
788 error_errno("fork (async) failed");
789 goto error;
790 }
791 if (!async->pid) {
792 if (need_in)
793 close(fdin[1]);
794 if (need_out)
795 close(fdout[0]);
796 git_atexit_clear();
797 process_is_async = 1;
798 exit(!!async->proc(proc_in, proc_out, async->data));
799 }
800
801 mark_child_for_cleanup(async->pid, NULL);
802
803 if (need_in)
804 close(fdin[0]);
805 else if (async->in)
806 close(async->in);
807
808 if (need_out)
809 close(fdout[1]);
810 else if (async->out)
811 close(async->out);
812 #else
813 if (!main_thread_set) {
814 /*
815 * We assume that the first time that start_async is called
816 * it is from the main thread.
817 */
818 main_thread_set = 1;
819 main_thread = pthread_self();
820 pthread_key_create(&async_key, NULL);
821 pthread_key_create(&async_die_counter, NULL);
822 set_die_routine(die_async);
823 set_die_is_recursing_routine(async_die_is_recursing);
824 }
825
826 if (proc_in >= 0)
827 set_cloexec(proc_in);
828 if (proc_out >= 0)
829 set_cloexec(proc_out);
830 async->proc_in = proc_in;
831 async->proc_out = proc_out;
832 {
833 int err = pthread_create(&async->tid, NULL, run_thread, async);
834 if (err) {
835 error_errno("cannot create thread");
836 goto error;
837 }
838 }
839 #endif
840 return 0;
841
842 error:
843 if (need_in)
844 close_pair(fdin);
845 else if (async->in)
846 close(async->in);
847
848 if (need_out)
849 close_pair(fdout);
850 else if (async->out)
851 close(async->out);
852 return -1;
853 }
854
855 int finish_async(struct async *async)
856 {
857 #ifdef NO_PTHREADS
858 return wait_or_whine(async->pid, "child process", 0);
859 #else
860 void *ret = (void *)(intptr_t)(-1);
861
862 if (pthread_join(async->tid, &ret))
863 error("pthread_join failed");
864 return (int)(intptr_t)ret;
865 #endif
866 }
867
868 const char *find_hook(const char *name)
869 {
870 static struct strbuf path = STRBUF_INIT;
871
872 strbuf_reset(&path);
873 strbuf_git_path(&path, "hooks/%s", name);
874 if (access(path.buf, X_OK) < 0)
875 return NULL;
876 return path.buf;
877 }
878
879 int run_hook_ve(const char *const *env, const char *name, va_list args)
880 {
881 struct child_process hook = CHILD_PROCESS_INIT;
882 const char *p;
883
884 p = find_hook(name);
885 if (!p)
886 return 0;
887
888 argv_array_push(&hook.args, p);
889 while ((p = va_arg(args, const char *)))
890 argv_array_push(&hook.args, p);
891 hook.env = env;
892 hook.no_stdin = 1;
893 hook.stdout_to_stderr = 1;
894
895 return run_command(&hook);
896 }
897
898 int run_hook_le(const char *const *env, const char *name, ...)
899 {
900 va_list args;
901 int ret;
902
903 va_start(args, name);
904 ret = run_hook_ve(env, name, args);
905 va_end(args);
906
907 return ret;
908 }
909
910 struct io_pump {
911 /* initialized by caller */
912 int fd;
913 int type; /* POLLOUT or POLLIN */
914 union {
915 struct {
916 const char *buf;
917 size_t len;
918 } out;
919 struct {
920 struct strbuf *buf;
921 size_t hint;
922 } in;
923 } u;
924
925 /* returned by pump_io */
926 int error; /* 0 for success, otherwise errno */
927
928 /* internal use */
929 struct pollfd *pfd;
930 };
931
932 static int pump_io_round(struct io_pump *slots, int nr, struct pollfd *pfd)
933 {
934 int pollsize = 0;
935 int i;
936
937 for (i = 0; i < nr; i++) {
938 struct io_pump *io = &slots[i];
939 if (io->fd < 0)
940 continue;
941 pfd[pollsize].fd = io->fd;
942 pfd[pollsize].events = io->type;
943 io->pfd = &pfd[pollsize++];
944 }
945
946 if (!pollsize)
947 return 0;
948
949 if (poll(pfd, pollsize, -1) < 0) {
950 if (errno == EINTR)
951 return 1;
952 die_errno("poll failed");
953 }
954
955 for (i = 0; i < nr; i++) {
956 struct io_pump *io = &slots[i];
957
958 if (io->fd < 0)
959 continue;
960
961 if (!(io->pfd->revents & (POLLOUT|POLLIN|POLLHUP|POLLERR|POLLNVAL)))
962 continue;
963
964 if (io->type == POLLOUT) {
965 ssize_t len = xwrite(io->fd,
966 io->u.out.buf, io->u.out.len);
967 if (len < 0) {
968 io->error = errno;
969 close(io->fd);
970 io->fd = -1;
971 } else {
972 io->u.out.buf += len;
973 io->u.out.len -= len;
974 if (!io->u.out.len) {
975 close(io->fd);
976 io->fd = -1;
977 }
978 }
979 }
980
981 if (io->type == POLLIN) {
982 ssize_t len = strbuf_read_once(io->u.in.buf,
983 io->fd, io->u.in.hint);
984 if (len < 0)
985 io->error = errno;
986 if (len <= 0) {
987 close(io->fd);
988 io->fd = -1;
989 }
990 }
991 }
992
993 return 1;
994 }
995
996 static int pump_io(struct io_pump *slots, int nr)
997 {
998 struct pollfd *pfd;
999 int i;
1000
1001 for (i = 0; i < nr; i++)
1002 slots[i].error = 0;
1003
1004 ALLOC_ARRAY(pfd, nr);
1005 while (pump_io_round(slots, nr, pfd))
1006 ; /* nothing */
1007 free(pfd);
1008
1009 /* There may be multiple errno values, so just pick the first. */
1010 for (i = 0; i < nr; i++) {
1011 if (slots[i].error) {
1012 errno = slots[i].error;
1013 return -1;
1014 }
1015 }
1016 return 0;
1017 }
1018
1019
1020 int pipe_command(struct child_process *cmd,
1021 const char *in, size_t in_len,
1022 struct strbuf *out, size_t out_hint,
1023 struct strbuf *err, size_t err_hint)
1024 {
1025 struct io_pump io[3];
1026 int nr = 0;
1027
1028 if (in)
1029 cmd->in = -1;
1030 if (out)
1031 cmd->out = -1;
1032 if (err)
1033 cmd->err = -1;
1034
1035 if (start_command(cmd) < 0)
1036 return -1;
1037
1038 if (in) {
1039 io[nr].fd = cmd->in;
1040 io[nr].type = POLLOUT;
1041 io[nr].u.out.buf = in;
1042 io[nr].u.out.len = in_len;
1043 nr++;
1044 }
1045 if (out) {
1046 io[nr].fd = cmd->out;
1047 io[nr].type = POLLIN;
1048 io[nr].u.in.buf = out;
1049 io[nr].u.in.hint = out_hint;
1050 nr++;
1051 }
1052 if (err) {
1053 io[nr].fd = cmd->err;
1054 io[nr].type = POLLIN;
1055 io[nr].u.in.buf = err;
1056 io[nr].u.in.hint = err_hint;
1057 nr++;
1058 }
1059
1060 if (pump_io(io, nr) < 0) {
1061 finish_command(cmd); /* throw away exit code */
1062 return -1;
1063 }
1064
1065 return finish_command(cmd);
1066 }
1067
1068 enum child_state {
1069 GIT_CP_FREE,
1070 GIT_CP_WORKING,
1071 GIT_CP_WAIT_CLEANUP,
1072 };
1073
1074 struct parallel_processes {
1075 void *data;
1076
1077 int max_processes;
1078 int nr_processes;
1079
1080 get_next_task_fn get_next_task;
1081 start_failure_fn start_failure;
1082 task_finished_fn task_finished;
1083
1084 struct {
1085 enum child_state state;
1086 struct child_process process;
1087 struct strbuf err;
1088 void *data;
1089 } *children;
1090 /*
1091 * The struct pollfd is logically part of *children,
1092 * but the system call expects it as its own array.
1093 */
1094 struct pollfd *pfd;
1095
1096 unsigned shutdown : 1;
1097
1098 int output_owner;
1099 struct strbuf buffered_output; /* of finished children */
1100 };
1101
1102 static int default_start_failure(struct strbuf *out,
1103 void *pp_cb,
1104 void *pp_task_cb)
1105 {
1106 return 0;
1107 }
1108
1109 static int default_task_finished(int result,
1110 struct strbuf *out,
1111 void *pp_cb,
1112 void *pp_task_cb)
1113 {
1114 return 0;
1115 }
1116
1117 static void kill_children(struct parallel_processes *pp, int signo)
1118 {
1119 int i, n = pp->max_processes;
1120
1121 for (i = 0; i < n; i++)
1122 if (pp->children[i].state == GIT_CP_WORKING)
1123 kill(pp->children[i].process.pid, signo);
1124 }
1125
1126 static struct parallel_processes *pp_for_signal;
1127
1128 static void handle_children_on_signal(int signo)
1129 {
1130 kill_children(pp_for_signal, signo);
1131 sigchain_pop(signo);
1132 raise(signo);
1133 }
1134
1135 static void pp_init(struct parallel_processes *pp,
1136 int n,
1137 get_next_task_fn get_next_task,
1138 start_failure_fn start_failure,
1139 task_finished_fn task_finished,
1140 void *data)
1141 {
1142 int i;
1143
1144 if (n < 1)
1145 n = online_cpus();
1146
1147 pp->max_processes = n;
1148
1149 trace_printf("run_processes_parallel: preparing to run up to %d tasks", n);
1150
1151 pp->data = data;
1152 if (!get_next_task)
1153 die("BUG: you need to specify a get_next_task function");
1154 pp->get_next_task = get_next_task;
1155
1156 pp->start_failure = start_failure ? start_failure : default_start_failure;
1157 pp->task_finished = task_finished ? task_finished : default_task_finished;
1158
1159 pp->nr_processes = 0;
1160 pp->output_owner = 0;
1161 pp->shutdown = 0;
1162 pp->children = xcalloc(n, sizeof(*pp->children));
1163 pp->pfd = xcalloc(n, sizeof(*pp->pfd));
1164 strbuf_init(&pp->buffered_output, 0);
1165
1166 for (i = 0; i < n; i++) {
1167 strbuf_init(&pp->children[i].err, 0);
1168 child_process_init(&pp->children[i].process);
1169 pp->pfd[i].events = POLLIN | POLLHUP;
1170 pp->pfd[i].fd = -1;
1171 }
1172
1173 pp_for_signal = pp;
1174 sigchain_push_common(handle_children_on_signal);
1175 }
1176
1177 static void pp_cleanup(struct parallel_processes *pp)
1178 {
1179 int i;
1180
1181 trace_printf("run_processes_parallel: done");
1182 for (i = 0; i < pp->max_processes; i++) {
1183 strbuf_release(&pp->children[i].err);
1184 child_process_clear(&pp->children[i].process);
1185 }
1186
1187 free(pp->children);
1188 free(pp->pfd);
1189
1190 /*
1191 * When get_next_task added messages to the buffer in its last
1192 * iteration, the buffered output is non empty.
1193 */
1194 strbuf_write(&pp->buffered_output, stderr);
1195 strbuf_release(&pp->buffered_output);
1196
1197 sigchain_pop_common();
1198 }
1199
1200 /* returns
1201 * 0 if a new task was started.
1202 * 1 if no new jobs was started (get_next_task ran out of work, non critical
1203 * problem with starting a new command)
1204 * <0 no new job was started, user wishes to shutdown early. Use negative code
1205 * to signal the children.
1206 */
1207 static int pp_start_one(struct parallel_processes *pp)
1208 {
1209 int i, code;
1210
1211 for (i = 0; i < pp->max_processes; i++)
1212 if (pp->children[i].state == GIT_CP_FREE)
1213 break;
1214 if (i == pp->max_processes)
1215 die("BUG: bookkeeping is hard");
1216
1217 code = pp->get_next_task(&pp->children[i].process,
1218 &pp->children[i].err,
1219 pp->data,
1220 &pp->children[i].data);
1221 if (!code) {
1222 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1223 strbuf_reset(&pp->children[i].err);
1224 return 1;
1225 }
1226 pp->children[i].process.err = -1;
1227 pp->children[i].process.stdout_to_stderr = 1;
1228 pp->children[i].process.no_stdin = 1;
1229
1230 if (start_command(&pp->children[i].process)) {
1231 code = pp->start_failure(&pp->children[i].err,
1232 pp->data,
1233 &pp->children[i].data);
1234 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1235 strbuf_reset(&pp->children[i].err);
1236 if (code)
1237 pp->shutdown = 1;
1238 return code;
1239 }
1240
1241 pp->nr_processes++;
1242 pp->children[i].state = GIT_CP_WORKING;
1243 pp->pfd[i].fd = pp->children[i].process.err;
1244 return 0;
1245 }
1246
1247 static void pp_buffer_stderr(struct parallel_processes *pp, int output_timeout)
1248 {
1249 int i;
1250
1251 while ((i = poll(pp->pfd, pp->max_processes, output_timeout)) < 0) {
1252 if (errno == EINTR)
1253 continue;
1254 pp_cleanup(pp);
1255 die_errno("poll");
1256 }
1257
1258 /* Buffer output from all pipes. */
1259 for (i = 0; i < pp->max_processes; i++) {
1260 if (pp->children[i].state == GIT_CP_WORKING &&
1261 pp->pfd[i].revents & (POLLIN | POLLHUP)) {
1262 int n = strbuf_read_once(&pp->children[i].err,
1263 pp->children[i].process.err, 0);
1264 if (n == 0) {
1265 close(pp->children[i].process.err);
1266 pp->children[i].state = GIT_CP_WAIT_CLEANUP;
1267 } else if (n < 0)
1268 if (errno != EAGAIN)
1269 die_errno("read");
1270 }
1271 }
1272 }
1273
1274 static void pp_output(struct parallel_processes *pp)
1275 {
1276 int i = pp->output_owner;
1277 if (pp->children[i].state == GIT_CP_WORKING &&
1278 pp->children[i].err.len) {
1279 strbuf_write(&pp->children[i].err, stderr);
1280 strbuf_reset(&pp->children[i].err);
1281 }
1282 }
1283
1284 static int pp_collect_finished(struct parallel_processes *pp)
1285 {
1286 int i, code;
1287 int n = pp->max_processes;
1288 int result = 0;
1289
1290 while (pp->nr_processes > 0) {
1291 for (i = 0; i < pp->max_processes; i++)
1292 if (pp->children[i].state == GIT_CP_WAIT_CLEANUP)
1293 break;
1294 if (i == pp->max_processes)
1295 break;
1296
1297 code = finish_command(&pp->children[i].process);
1298
1299 code = pp->task_finished(code,
1300 &pp->children[i].err, pp->data,
1301 &pp->children[i].data);
1302
1303 if (code)
1304 result = code;
1305 if (code < 0)
1306 break;
1307
1308 pp->nr_processes--;
1309 pp->children[i].state = GIT_CP_FREE;
1310 pp->pfd[i].fd = -1;
1311 child_process_init(&pp->children[i].process);
1312
1313 if (i != pp->output_owner) {
1314 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1315 strbuf_reset(&pp->children[i].err);
1316 } else {
1317 strbuf_write(&pp->children[i].err, stderr);
1318 strbuf_reset(&pp->children[i].err);
1319
1320 /* Output all other finished child processes */
1321 strbuf_write(&pp->buffered_output, stderr);
1322 strbuf_reset(&pp->buffered_output);
1323
1324 /*
1325 * Pick next process to output live.
1326 * NEEDSWORK:
1327 * For now we pick it randomly by doing a round
1328 * robin. Later we may want to pick the one with
1329 * the most output or the longest or shortest
1330 * running process time.
1331 */
1332 for (i = 0; i < n; i++)
1333 if (pp->children[(pp->output_owner + i) % n].state == GIT_CP_WORKING)
1334 break;
1335 pp->output_owner = (pp->output_owner + i) % n;
1336 }
1337 }
1338 return result;
1339 }
1340
1341 int run_processes_parallel(int n,
1342 get_next_task_fn get_next_task,
1343 start_failure_fn start_failure,
1344 task_finished_fn task_finished,
1345 void *pp_cb)
1346 {
1347 int i, code;
1348 int output_timeout = 100;
1349 int spawn_cap = 4;
1350 struct parallel_processes pp;
1351
1352 pp_init(&pp, n, get_next_task, start_failure, task_finished, pp_cb);
1353 while (1) {
1354 for (i = 0;
1355 i < spawn_cap && !pp.shutdown &&
1356 pp.nr_processes < pp.max_processes;
1357 i++) {
1358 code = pp_start_one(&pp);
1359 if (!code)
1360 continue;
1361 if (code < 0) {
1362 pp.shutdown = 1;
1363 kill_children(&pp, -code);
1364 }
1365 break;
1366 }
1367 if (!pp.nr_processes)
1368 break;
1369 pp_buffer_stderr(&pp, output_timeout);
1370 pp_output(&pp);
1371 code = pp_collect_finished(&pp);
1372 if (code) {
1373 pp.shutdown = 1;
1374 if (code < 0)
1375 kill_children(&pp, -code);
1376 }
1377 }
1378
1379 pp_cleanup(&pp);
1380 return 0;
1381 }
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