Merge branch 'cs/pretty-formats-doc-typofix'
[git/git.git] / run-command.c
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 #include "string-list.h"
9 #include "quote.h"
10
11 void child_process_init(struct child_process *child)
12 {
13 memset(child, 0, sizeof(*child));
14 argv_array_init(&child->args);
15 argv_array_init(&child->env_array);
16 }
17
18 void child_process_clear(struct child_process *child)
19 {
20 argv_array_clear(&child->args);
21 argv_array_clear(&child->env_array);
22 }
23
24 struct child_to_clean {
25 pid_t pid;
26 struct child_process *process;
27 struct child_to_clean *next;
28 };
29 static struct child_to_clean *children_to_clean;
30 static int installed_child_cleanup_handler;
31
32 static void cleanup_children(int sig, int in_signal)
33 {
34 struct child_to_clean *children_to_wait_for = NULL;
35
36 while (children_to_clean) {
37 struct child_to_clean *p = children_to_clean;
38 children_to_clean = p->next;
39
40 if (p->process && !in_signal) {
41 struct child_process *process = p->process;
42 if (process->clean_on_exit_handler) {
43 trace_printf(
44 "trace: run_command: running exit handler for pid %"
45 PRIuMAX, (uintmax_t)p->pid
46 );
47 process->clean_on_exit_handler(process);
48 }
49 }
50
51 kill(p->pid, sig);
52
53 if (p->process && p->process->wait_after_clean) {
54 p->next = children_to_wait_for;
55 children_to_wait_for = p;
56 } else {
57 if (!in_signal)
58 free(p);
59 }
60 }
61
62 while (children_to_wait_for) {
63 struct child_to_clean *p = children_to_wait_for;
64 children_to_wait_for = p->next;
65
66 while (waitpid(p->pid, NULL, 0) < 0 && errno == EINTR)
67 ; /* spin waiting for process exit or error */
68
69 if (!in_signal)
70 free(p);
71 }
72 }
73
74 static void cleanup_children_on_signal(int sig)
75 {
76 cleanup_children(sig, 1);
77 sigchain_pop(sig);
78 raise(sig);
79 }
80
81 static void cleanup_children_on_exit(void)
82 {
83 cleanup_children(SIGTERM, 0);
84 }
85
86 static void mark_child_for_cleanup(pid_t pid, struct child_process *process)
87 {
88 struct child_to_clean *p = xmalloc(sizeof(*p));
89 p->pid = pid;
90 p->process = process;
91 p->next = children_to_clean;
92 children_to_clean = p;
93
94 if (!installed_child_cleanup_handler) {
95 atexit(cleanup_children_on_exit);
96 sigchain_push_common(cleanup_children_on_signal);
97 installed_child_cleanup_handler = 1;
98 }
99 }
100
101 static void clear_child_for_cleanup(pid_t pid)
102 {
103 struct child_to_clean **pp;
104
105 for (pp = &children_to_clean; *pp; pp = &(*pp)->next) {
106 struct child_to_clean *clean_me = *pp;
107
108 if (clean_me->pid == pid) {
109 *pp = clean_me->next;
110 free(clean_me);
111 return;
112 }
113 }
114 }
115
116 static inline void close_pair(int fd[2])
117 {
118 close(fd[0]);
119 close(fd[1]);
120 }
121
122 int is_executable(const char *name)
123 {
124 struct stat st;
125
126 if (stat(name, &st) || /* stat, not lstat */
127 !S_ISREG(st.st_mode))
128 return 0;
129
130 #if defined(GIT_WINDOWS_NATIVE)
131 /*
132 * On Windows there is no executable bit. The file extension
133 * indicates whether it can be run as an executable, and Git
134 * has special-handling to detect scripts and launch them
135 * through the indicated script interpreter. We test for the
136 * file extension first because virus scanners may make
137 * it quite expensive to open many files.
138 */
139 if (ends_with(name, ".exe"))
140 return S_IXUSR;
141
142 {
143 /*
144 * Now that we know it does not have an executable extension,
145 * peek into the file instead.
146 */
147 char buf[3] = { 0 };
148 int n;
149 int fd = open(name, O_RDONLY);
150 st.st_mode &= ~S_IXUSR;
151 if (fd >= 0) {
152 n = read(fd, buf, 2);
153 if (n == 2)
154 /* look for a she-bang */
155 if (!strcmp(buf, "#!"))
156 st.st_mode |= S_IXUSR;
157 close(fd);
158 }
159 }
160 #endif
161 return st.st_mode & S_IXUSR;
162 }
163
164 /*
165 * Search $PATH for a command. This emulates the path search that
166 * execvp would perform, without actually executing the command so it
167 * can be used before fork() to prepare to run a command using
168 * execve() or after execvp() to diagnose why it failed.
169 *
170 * The caller should ensure that file contains no directory
171 * separators.
172 *
173 * Returns the path to the command, as found in $PATH or NULL if the
174 * command could not be found. The caller inherits ownership of the memory
175 * used to store the resultant path.
176 *
177 * This should not be used on Windows, where the $PATH search rules
178 * are more complicated (e.g., a search for "foo" should find
179 * "foo.exe").
180 */
181 static char *locate_in_PATH(const char *file)
182 {
183 const char *p = getenv("PATH");
184 struct strbuf buf = STRBUF_INIT;
185
186 if (!p || !*p)
187 return NULL;
188
189 while (1) {
190 const char *end = strchrnul(p, ':');
191
192 strbuf_reset(&buf);
193
194 /* POSIX specifies an empty entry as the current directory. */
195 if (end != p) {
196 strbuf_add(&buf, p, end - p);
197 strbuf_addch(&buf, '/');
198 }
199 strbuf_addstr(&buf, file);
200
201 if (is_executable(buf.buf))
202 return strbuf_detach(&buf, NULL);
203
204 if (!*end)
205 break;
206 p = end + 1;
207 }
208
209 strbuf_release(&buf);
210 return NULL;
211 }
212
213 static int exists_in_PATH(const char *file)
214 {
215 char *r = locate_in_PATH(file);
216 free(r);
217 return r != NULL;
218 }
219
220 int sane_execvp(const char *file, char * const argv[])
221 {
222 #ifndef GIT_WINDOWS_NATIVE
223 /*
224 * execvp() doesn't return, so we all we can do is tell trace2
225 * what we are about to do and let it leave a hint in the log
226 * (unless of course the execvp() fails).
227 *
228 * we skip this for Windows because the compat layer already
229 * has to emulate the execvp() call anyway.
230 */
231 int exec_id = trace2_exec(file, (const char **)argv);
232 #endif
233
234 if (!execvp(file, argv))
235 return 0; /* cannot happen ;-) */
236
237 #ifndef GIT_WINDOWS_NATIVE
238 {
239 int ec = errno;
240 trace2_exec_result(exec_id, ec);
241 errno = ec;
242 }
243 #endif
244
245 /*
246 * When a command can't be found because one of the directories
247 * listed in $PATH is unsearchable, execvp reports EACCES, but
248 * careful usability testing (read: analysis of occasional bug
249 * reports) reveals that "No such file or directory" is more
250 * intuitive.
251 *
252 * We avoid commands with "/", because execvp will not do $PATH
253 * lookups in that case.
254 *
255 * The reassignment of EACCES to errno looks like a no-op below,
256 * but we need to protect against exists_in_PATH overwriting errno.
257 */
258 if (errno == EACCES && !strchr(file, '/'))
259 errno = exists_in_PATH(file) ? EACCES : ENOENT;
260 else if (errno == ENOTDIR && !strchr(file, '/'))
261 errno = ENOENT;
262 return -1;
263 }
264
265 static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
266 {
267 if (!argv[0])
268 BUG("shell command is empty");
269
270 if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
271 #ifndef GIT_WINDOWS_NATIVE
272 argv_array_push(out, SHELL_PATH);
273 #else
274 argv_array_push(out, "sh");
275 #endif
276 argv_array_push(out, "-c");
277
278 /*
279 * If we have no extra arguments, we do not even need to
280 * bother with the "$@" magic.
281 */
282 if (!argv[1])
283 argv_array_push(out, argv[0]);
284 else
285 argv_array_pushf(out, "%s \"$@\"", argv[0]);
286 }
287
288 argv_array_pushv(out, argv);
289 return out->argv;
290 }
291
292 #ifndef GIT_WINDOWS_NATIVE
293 static int child_notifier = -1;
294
295 enum child_errcode {
296 CHILD_ERR_CHDIR,
297 CHILD_ERR_DUP2,
298 CHILD_ERR_CLOSE,
299 CHILD_ERR_SIGPROCMASK,
300 CHILD_ERR_ENOENT,
301 CHILD_ERR_SILENT,
302 CHILD_ERR_ERRNO
303 };
304
305 struct child_err {
306 enum child_errcode err;
307 int syserr; /* errno */
308 };
309
310 static void child_die(enum child_errcode err)
311 {
312 struct child_err buf;
313
314 buf.err = err;
315 buf.syserr = errno;
316
317 /* write(2) on buf smaller than PIPE_BUF (min 512) is atomic: */
318 xwrite(child_notifier, &buf, sizeof(buf));
319 _exit(1);
320 }
321
322 static void child_dup2(int fd, int to)
323 {
324 if (dup2(fd, to) < 0)
325 child_die(CHILD_ERR_DUP2);
326 }
327
328 static void child_close(int fd)
329 {
330 if (close(fd))
331 child_die(CHILD_ERR_CLOSE);
332 }
333
334 static void child_close_pair(int fd[2])
335 {
336 child_close(fd[0]);
337 child_close(fd[1]);
338 }
339
340 /*
341 * parent will make it look like the child spewed a fatal error and died
342 * this is needed to prevent changes to t0061.
343 */
344 static void fake_fatal(const char *err, va_list params)
345 {
346 vreportf("fatal: ", err, params);
347 }
348
349 static void child_error_fn(const char *err, va_list params)
350 {
351 const char msg[] = "error() should not be called in child\n";
352 xwrite(2, msg, sizeof(msg) - 1);
353 }
354
355 static void child_warn_fn(const char *err, va_list params)
356 {
357 const char msg[] = "warn() should not be called in child\n";
358 xwrite(2, msg, sizeof(msg) - 1);
359 }
360
361 static void NORETURN child_die_fn(const char *err, va_list params)
362 {
363 const char msg[] = "die() should not be called in child\n";
364 xwrite(2, msg, sizeof(msg) - 1);
365 _exit(2);
366 }
367
368 /* this runs in the parent process */
369 static void child_err_spew(struct child_process *cmd, struct child_err *cerr)
370 {
371 static void (*old_errfn)(const char *err, va_list params);
372
373 old_errfn = get_error_routine();
374 set_error_routine(fake_fatal);
375 errno = cerr->syserr;
376
377 switch (cerr->err) {
378 case CHILD_ERR_CHDIR:
379 error_errno("exec '%s': cd to '%s' failed",
380 cmd->argv[0], cmd->dir);
381 break;
382 case CHILD_ERR_DUP2:
383 error_errno("dup2() in child failed");
384 break;
385 case CHILD_ERR_CLOSE:
386 error_errno("close() in child failed");
387 break;
388 case CHILD_ERR_SIGPROCMASK:
389 error_errno("sigprocmask failed restoring signals");
390 break;
391 case CHILD_ERR_ENOENT:
392 error_errno("cannot run %s", cmd->argv[0]);
393 break;
394 case CHILD_ERR_SILENT:
395 break;
396 case CHILD_ERR_ERRNO:
397 error_errno("cannot exec '%s'", cmd->argv[0]);
398 break;
399 }
400 set_error_routine(old_errfn);
401 }
402
403 static int prepare_cmd(struct argv_array *out, const struct child_process *cmd)
404 {
405 if (!cmd->argv[0])
406 BUG("command is empty");
407
408 /*
409 * Add SHELL_PATH so in the event exec fails with ENOEXEC we can
410 * attempt to interpret the command with 'sh'.
411 */
412 argv_array_push(out, SHELL_PATH);
413
414 if (cmd->git_cmd) {
415 argv_array_push(out, "git");
416 argv_array_pushv(out, cmd->argv);
417 } else if (cmd->use_shell) {
418 prepare_shell_cmd(out, cmd->argv);
419 } else {
420 argv_array_pushv(out, cmd->argv);
421 }
422
423 /*
424 * If there are no '/' characters in the command then perform a path
425 * lookup and use the resolved path as the command to exec. If there
426 * are '/' characters, we have exec attempt to invoke the command
427 * directly.
428 */
429 if (!strchr(out->argv[1], '/')) {
430 char *program = locate_in_PATH(out->argv[1]);
431 if (program) {
432 free((char *)out->argv[1]);
433 out->argv[1] = program;
434 } else {
435 argv_array_clear(out);
436 errno = ENOENT;
437 return -1;
438 }
439 }
440
441 return 0;
442 }
443
444 static char **prep_childenv(const char *const *deltaenv)
445 {
446 extern char **environ;
447 char **childenv;
448 struct string_list env = STRING_LIST_INIT_DUP;
449 struct strbuf key = STRBUF_INIT;
450 const char *const *p;
451 int i;
452
453 /* Construct a sorted string list consisting of the current environ */
454 for (p = (const char *const *) environ; p && *p; p++) {
455 const char *equals = strchr(*p, '=');
456
457 if (equals) {
458 strbuf_reset(&key);
459 strbuf_add(&key, *p, equals - *p);
460 string_list_append(&env, key.buf)->util = (void *) *p;
461 } else {
462 string_list_append(&env, *p)->util = (void *) *p;
463 }
464 }
465 string_list_sort(&env);
466
467 /* Merge in 'deltaenv' with the current environ */
468 for (p = deltaenv; p && *p; p++) {
469 const char *equals = strchr(*p, '=');
470
471 if (equals) {
472 /* ('key=value'), insert or replace entry */
473 strbuf_reset(&key);
474 strbuf_add(&key, *p, equals - *p);
475 string_list_insert(&env, key.buf)->util = (void *) *p;
476 } else {
477 /* otherwise ('key') remove existing entry */
478 string_list_remove(&env, *p, 0);
479 }
480 }
481
482 /* Create an array of 'char *' to be used as the childenv */
483 ALLOC_ARRAY(childenv, env.nr + 1);
484 for (i = 0; i < env.nr; i++)
485 childenv[i] = env.items[i].util;
486 childenv[env.nr] = NULL;
487
488 string_list_clear(&env, 0);
489 strbuf_release(&key);
490 return childenv;
491 }
492
493 struct atfork_state {
494 #ifndef NO_PTHREADS
495 int cs;
496 #endif
497 sigset_t old;
498 };
499
500 #define CHECK_BUG(err, msg) \
501 do { \
502 int e = (err); \
503 if (e) \
504 BUG("%s: %s", msg, strerror(e)); \
505 } while(0)
506
507 static void atfork_prepare(struct atfork_state *as)
508 {
509 sigset_t all;
510
511 if (sigfillset(&all))
512 die_errno("sigfillset");
513 #ifdef NO_PTHREADS
514 if (sigprocmask(SIG_SETMASK, &all, &as->old))
515 die_errno("sigprocmask");
516 #else
517 CHECK_BUG(pthread_sigmask(SIG_SETMASK, &all, &as->old),
518 "blocking all signals");
519 CHECK_BUG(pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &as->cs),
520 "disabling cancellation");
521 #endif
522 }
523
524 static void atfork_parent(struct atfork_state *as)
525 {
526 #ifdef NO_PTHREADS
527 if (sigprocmask(SIG_SETMASK, &as->old, NULL))
528 die_errno("sigprocmask");
529 #else
530 CHECK_BUG(pthread_setcancelstate(as->cs, NULL),
531 "re-enabling cancellation");
532 CHECK_BUG(pthread_sigmask(SIG_SETMASK, &as->old, NULL),
533 "restoring signal mask");
534 #endif
535 }
536 #endif /* GIT_WINDOWS_NATIVE */
537
538 static inline void set_cloexec(int fd)
539 {
540 int flags = fcntl(fd, F_GETFD);
541 if (flags >= 0)
542 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
543 }
544
545 static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
546 {
547 int status, code = -1;
548 pid_t waiting;
549 int failed_errno = 0;
550
551 while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
552 ; /* nothing */
553 if (in_signal)
554 return 0;
555
556 if (waiting < 0) {
557 failed_errno = errno;
558 error_errno("waitpid for %s failed", argv0);
559 } else if (waiting != pid) {
560 error("waitpid is confused (%s)", argv0);
561 } else if (WIFSIGNALED(status)) {
562 code = WTERMSIG(status);
563 if (code != SIGINT && code != SIGQUIT && code != SIGPIPE)
564 error("%s died of signal %d", argv0, code);
565 /*
566 * This return value is chosen so that code & 0xff
567 * mimics the exit code that a POSIX shell would report for
568 * a program that died from this signal.
569 */
570 code += 128;
571 } else if (WIFEXITED(status)) {
572 code = WEXITSTATUS(status);
573 } else {
574 error("waitpid is confused (%s)", argv0);
575 }
576
577 clear_child_for_cleanup(pid);
578
579 errno = failed_errno;
580 return code;
581 }
582
583 static void trace_add_env(struct strbuf *dst, const char *const *deltaenv)
584 {
585 struct string_list envs = STRING_LIST_INIT_DUP;
586 const char *const *e;
587 int i;
588 int printed_unset = 0;
589
590 /* Last one wins, see run-command.c:prep_childenv() for context */
591 for (e = deltaenv; e && *e; e++) {
592 struct strbuf key = STRBUF_INIT;
593 char *equals = strchr(*e, '=');
594
595 if (equals) {
596 strbuf_add(&key, *e, equals - *e);
597 string_list_insert(&envs, key.buf)->util = equals + 1;
598 } else {
599 string_list_insert(&envs, *e)->util = NULL;
600 }
601 strbuf_release(&key);
602 }
603
604 /* "unset X Y...;" */
605 for (i = 0; i < envs.nr; i++) {
606 const char *var = envs.items[i].string;
607 const char *val = envs.items[i].util;
608
609 if (val || !getenv(var))
610 continue;
611
612 if (!printed_unset) {
613 strbuf_addstr(dst, " unset");
614 printed_unset = 1;
615 }
616 strbuf_addf(dst, " %s", var);
617 }
618 if (printed_unset)
619 strbuf_addch(dst, ';');
620
621 /* ... followed by "A=B C=D ..." */
622 for (i = 0; i < envs.nr; i++) {
623 const char *var = envs.items[i].string;
624 const char *val = envs.items[i].util;
625 const char *oldval;
626
627 if (!val)
628 continue;
629
630 oldval = getenv(var);
631 if (oldval && !strcmp(val, oldval))
632 continue;
633
634 strbuf_addf(dst, " %s=", var);
635 sq_quote_buf_pretty(dst, val);
636 }
637 string_list_clear(&envs, 0);
638 }
639
640 static void trace_run_command(const struct child_process *cp)
641 {
642 struct strbuf buf = STRBUF_INIT;
643
644 if (!trace_want(&trace_default_key))
645 return;
646
647 strbuf_addstr(&buf, "trace: run_command:");
648 if (cp->dir) {
649 strbuf_addstr(&buf, " cd ");
650 sq_quote_buf_pretty(&buf, cp->dir);
651 strbuf_addch(&buf, ';');
652 }
653 /*
654 * The caller is responsible for initializing cp->env from
655 * cp->env_array if needed. We only check one place.
656 */
657 if (cp->env)
658 trace_add_env(&buf, cp->env);
659 if (cp->git_cmd)
660 strbuf_addstr(&buf, " git");
661 sq_quote_argv_pretty(&buf, cp->argv);
662
663 trace_printf("%s", buf.buf);
664 strbuf_release(&buf);
665 }
666
667 int start_command(struct child_process *cmd)
668 {
669 int need_in, need_out, need_err;
670 int fdin[2], fdout[2], fderr[2];
671 int failed_errno;
672 char *str;
673
674 if (!cmd->argv)
675 cmd->argv = cmd->args.argv;
676 if (!cmd->env)
677 cmd->env = cmd->env_array.argv;
678
679 /*
680 * In case of errors we must keep the promise to close FDs
681 * that have been passed in via ->in and ->out.
682 */
683
684 need_in = !cmd->no_stdin && cmd->in < 0;
685 if (need_in) {
686 if (pipe(fdin) < 0) {
687 failed_errno = errno;
688 if (cmd->out > 0)
689 close(cmd->out);
690 str = "standard input";
691 goto fail_pipe;
692 }
693 cmd->in = fdin[1];
694 }
695
696 need_out = !cmd->no_stdout
697 && !cmd->stdout_to_stderr
698 && cmd->out < 0;
699 if (need_out) {
700 if (pipe(fdout) < 0) {
701 failed_errno = errno;
702 if (need_in)
703 close_pair(fdin);
704 else if (cmd->in)
705 close(cmd->in);
706 str = "standard output";
707 goto fail_pipe;
708 }
709 cmd->out = fdout[0];
710 }
711
712 need_err = !cmd->no_stderr && cmd->err < 0;
713 if (need_err) {
714 if (pipe(fderr) < 0) {
715 failed_errno = errno;
716 if (need_in)
717 close_pair(fdin);
718 else if (cmd->in)
719 close(cmd->in);
720 if (need_out)
721 close_pair(fdout);
722 else if (cmd->out)
723 close(cmd->out);
724 str = "standard error";
725 fail_pipe:
726 error("cannot create %s pipe for %s: %s",
727 str, cmd->argv[0], strerror(failed_errno));
728 child_process_clear(cmd);
729 errno = failed_errno;
730 return -1;
731 }
732 cmd->err = fderr[0];
733 }
734
735 trace2_child_start(cmd);
736 trace_run_command(cmd);
737
738 fflush(NULL);
739
740 #ifndef GIT_WINDOWS_NATIVE
741 {
742 int notify_pipe[2];
743 int null_fd = -1;
744 char **childenv;
745 struct argv_array argv = ARGV_ARRAY_INIT;
746 struct child_err cerr;
747 struct atfork_state as;
748
749 if (prepare_cmd(&argv, cmd) < 0) {
750 failed_errno = errno;
751 cmd->pid = -1;
752 if (!cmd->silent_exec_failure)
753 error_errno("cannot run %s", cmd->argv[0]);
754 goto end_of_spawn;
755 }
756
757 if (pipe(notify_pipe))
758 notify_pipe[0] = notify_pipe[1] = -1;
759
760 if (cmd->no_stdin || cmd->no_stdout || cmd->no_stderr) {
761 null_fd = open("/dev/null", O_RDWR | O_CLOEXEC);
762 if (null_fd < 0)
763 die_errno(_("open /dev/null failed"));
764 set_cloexec(null_fd);
765 }
766
767 childenv = prep_childenv(cmd->env);
768 atfork_prepare(&as);
769
770 /*
771 * NOTE: In order to prevent deadlocking when using threads special
772 * care should be taken with the function calls made in between the
773 * fork() and exec() calls. No calls should be made to functions which
774 * require acquiring a lock (e.g. malloc) as the lock could have been
775 * held by another thread at the time of forking, causing the lock to
776 * never be released in the child process. This means only
777 * Async-Signal-Safe functions are permitted in the child.
778 */
779 cmd->pid = fork();
780 failed_errno = errno;
781 if (!cmd->pid) {
782 int sig;
783 /*
784 * Ensure the default die/error/warn routines do not get
785 * called, they can take stdio locks and malloc.
786 */
787 set_die_routine(child_die_fn);
788 set_error_routine(child_error_fn);
789 set_warn_routine(child_warn_fn);
790
791 close(notify_pipe[0]);
792 set_cloexec(notify_pipe[1]);
793 child_notifier = notify_pipe[1];
794
795 if (cmd->no_stdin)
796 child_dup2(null_fd, 0);
797 else if (need_in) {
798 child_dup2(fdin[0], 0);
799 child_close_pair(fdin);
800 } else if (cmd->in) {
801 child_dup2(cmd->in, 0);
802 child_close(cmd->in);
803 }
804
805 if (cmd->no_stderr)
806 child_dup2(null_fd, 2);
807 else if (need_err) {
808 child_dup2(fderr[1], 2);
809 child_close_pair(fderr);
810 } else if (cmd->err > 1) {
811 child_dup2(cmd->err, 2);
812 child_close(cmd->err);
813 }
814
815 if (cmd->no_stdout)
816 child_dup2(null_fd, 1);
817 else if (cmd->stdout_to_stderr)
818 child_dup2(2, 1);
819 else if (need_out) {
820 child_dup2(fdout[1], 1);
821 child_close_pair(fdout);
822 } else if (cmd->out > 1) {
823 child_dup2(cmd->out, 1);
824 child_close(cmd->out);
825 }
826
827 if (cmd->dir && chdir(cmd->dir))
828 child_die(CHILD_ERR_CHDIR);
829
830 /*
831 * restore default signal handlers here, in case
832 * we catch a signal right before execve below
833 */
834 for (sig = 1; sig < NSIG; sig++) {
835 /* ignored signals get reset to SIG_DFL on execve */
836 if (signal(sig, SIG_DFL) == SIG_IGN)
837 signal(sig, SIG_IGN);
838 }
839
840 if (sigprocmask(SIG_SETMASK, &as.old, NULL) != 0)
841 child_die(CHILD_ERR_SIGPROCMASK);
842
843 /*
844 * Attempt to exec using the command and arguments starting at
845 * argv.argv[1]. argv.argv[0] contains SHELL_PATH which will
846 * be used in the event exec failed with ENOEXEC at which point
847 * we will try to interpret the command using 'sh'.
848 */
849 execve(argv.argv[1], (char *const *) argv.argv + 1,
850 (char *const *) childenv);
851 if (errno == ENOEXEC)
852 execve(argv.argv[0], (char *const *) argv.argv,
853 (char *const *) childenv);
854
855 if (errno == ENOENT) {
856 if (cmd->silent_exec_failure)
857 child_die(CHILD_ERR_SILENT);
858 child_die(CHILD_ERR_ENOENT);
859 } else {
860 child_die(CHILD_ERR_ERRNO);
861 }
862 }
863 atfork_parent(&as);
864 if (cmd->pid < 0)
865 error_errno("cannot fork() for %s", cmd->argv[0]);
866 else if (cmd->clean_on_exit)
867 mark_child_for_cleanup(cmd->pid, cmd);
868
869 /*
870 * Wait for child's exec. If the exec succeeds (or if fork()
871 * failed), EOF is seen immediately by the parent. Otherwise, the
872 * child process sends a child_err struct.
873 * Note that use of this infrastructure is completely advisory,
874 * therefore, we keep error checks minimal.
875 */
876 close(notify_pipe[1]);
877 if (xread(notify_pipe[0], &cerr, sizeof(cerr)) == sizeof(cerr)) {
878 /*
879 * At this point we know that fork() succeeded, but exec()
880 * failed. Errors have been reported to our stderr.
881 */
882 wait_or_whine(cmd->pid, cmd->argv[0], 0);
883 child_err_spew(cmd, &cerr);
884 failed_errno = errno;
885 cmd->pid = -1;
886 }
887 close(notify_pipe[0]);
888
889 if (null_fd >= 0)
890 close(null_fd);
891 argv_array_clear(&argv);
892 free(childenv);
893 }
894 end_of_spawn:
895
896 #else
897 {
898 int fhin = 0, fhout = 1, fherr = 2;
899 const char **sargv = cmd->argv;
900 struct argv_array nargv = ARGV_ARRAY_INIT;
901
902 if (cmd->no_stdin)
903 fhin = open("/dev/null", O_RDWR);
904 else if (need_in)
905 fhin = dup(fdin[0]);
906 else if (cmd->in)
907 fhin = dup(cmd->in);
908
909 if (cmd->no_stderr)
910 fherr = open("/dev/null", O_RDWR);
911 else if (need_err)
912 fherr = dup(fderr[1]);
913 else if (cmd->err > 2)
914 fherr = dup(cmd->err);
915
916 if (cmd->no_stdout)
917 fhout = open("/dev/null", O_RDWR);
918 else if (cmd->stdout_to_stderr)
919 fhout = dup(fherr);
920 else if (need_out)
921 fhout = dup(fdout[1]);
922 else if (cmd->out > 1)
923 fhout = dup(cmd->out);
924
925 if (cmd->git_cmd)
926 cmd->argv = prepare_git_cmd(&nargv, cmd->argv);
927 else if (cmd->use_shell)
928 cmd->argv = prepare_shell_cmd(&nargv, cmd->argv);
929
930 cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
931 cmd->dir, fhin, fhout, fherr);
932 failed_errno = errno;
933 if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
934 error_errno("cannot spawn %s", cmd->argv[0]);
935 if (cmd->clean_on_exit && cmd->pid >= 0)
936 mark_child_for_cleanup(cmd->pid, cmd);
937
938 argv_array_clear(&nargv);
939 cmd->argv = sargv;
940 if (fhin != 0)
941 close(fhin);
942 if (fhout != 1)
943 close(fhout);
944 if (fherr != 2)
945 close(fherr);
946 }
947 #endif
948
949 if (cmd->pid < 0) {
950 trace2_child_exit(cmd, -1);
951
952 if (need_in)
953 close_pair(fdin);
954 else if (cmd->in)
955 close(cmd->in);
956 if (need_out)
957 close_pair(fdout);
958 else if (cmd->out)
959 close(cmd->out);
960 if (need_err)
961 close_pair(fderr);
962 else if (cmd->err)
963 close(cmd->err);
964 child_process_clear(cmd);
965 errno = failed_errno;
966 return -1;
967 }
968
969 if (need_in)
970 close(fdin[0]);
971 else if (cmd->in)
972 close(cmd->in);
973
974 if (need_out)
975 close(fdout[1]);
976 else if (cmd->out)
977 close(cmd->out);
978
979 if (need_err)
980 close(fderr[1]);
981 else if (cmd->err)
982 close(cmd->err);
983
984 return 0;
985 }
986
987 int finish_command(struct child_process *cmd)
988 {
989 int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
990 trace2_child_exit(cmd, ret);
991 child_process_clear(cmd);
992 return ret;
993 }
994
995 int finish_command_in_signal(struct child_process *cmd)
996 {
997 int ret = wait_or_whine(cmd->pid, cmd->argv[0], 1);
998 trace2_child_exit(cmd, ret);
999 return ret;
1000 }
1001
1002
1003 int run_command(struct child_process *cmd)
1004 {
1005 int code;
1006
1007 if (cmd->out < 0 || cmd->err < 0)
1008 BUG("run_command with a pipe can cause deadlock");
1009
1010 code = start_command(cmd);
1011 if (code)
1012 return code;
1013 return finish_command(cmd);
1014 }
1015
1016 int run_command_v_opt(const char **argv, int opt)
1017 {
1018 return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
1019 }
1020
1021 int run_command_v_opt_tr2(const char **argv, int opt, const char *tr2_class)
1022 {
1023 return run_command_v_opt_cd_env_tr2(argv, opt, NULL, NULL, tr2_class);
1024 }
1025
1026 int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
1027 {
1028 return run_command_v_opt_cd_env_tr2(argv, opt, dir, env, NULL);
1029 }
1030
1031 int run_command_v_opt_cd_env_tr2(const char **argv, int opt, const char *dir,
1032 const char *const *env, const char *tr2_class)
1033 {
1034 struct child_process cmd = CHILD_PROCESS_INIT;
1035 cmd.argv = argv;
1036 cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
1037 cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
1038 cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
1039 cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
1040 cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
1041 cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
1042 cmd.dir = dir;
1043 cmd.env = env;
1044 cmd.trace2_child_class = tr2_class;
1045 return run_command(&cmd);
1046 }
1047
1048 #ifndef NO_PTHREADS
1049 static pthread_t main_thread;
1050 static int main_thread_set;
1051 static pthread_key_t async_key;
1052 static pthread_key_t async_die_counter;
1053
1054 static void *run_thread(void *data)
1055 {
1056 struct async *async = data;
1057 intptr_t ret;
1058
1059 if (async->isolate_sigpipe) {
1060 sigset_t mask;
1061 sigemptyset(&mask);
1062 sigaddset(&mask, SIGPIPE);
1063 if (pthread_sigmask(SIG_BLOCK, &mask, NULL) < 0) {
1064 ret = error("unable to block SIGPIPE in async thread");
1065 return (void *)ret;
1066 }
1067 }
1068
1069 pthread_setspecific(async_key, async);
1070 ret = async->proc(async->proc_in, async->proc_out, async->data);
1071 return (void *)ret;
1072 }
1073
1074 static NORETURN void die_async(const char *err, va_list params)
1075 {
1076 vreportf("fatal: ", err, params);
1077
1078 if (in_async()) {
1079 struct async *async = pthread_getspecific(async_key);
1080 if (async->proc_in >= 0)
1081 close(async->proc_in);
1082 if (async->proc_out >= 0)
1083 close(async->proc_out);
1084 pthread_exit((void *)128);
1085 }
1086
1087 exit(128);
1088 }
1089
1090 static int async_die_is_recursing(void)
1091 {
1092 void *ret = pthread_getspecific(async_die_counter);
1093 pthread_setspecific(async_die_counter, (void *)1);
1094 return ret != NULL;
1095 }
1096
1097 int in_async(void)
1098 {
1099 if (!main_thread_set)
1100 return 0; /* no asyncs started yet */
1101 return !pthread_equal(main_thread, pthread_self());
1102 }
1103
1104 static void NORETURN async_exit(int code)
1105 {
1106 pthread_exit((void *)(intptr_t)code);
1107 }
1108
1109 #else
1110
1111 static struct {
1112 void (**handlers)(void);
1113 size_t nr;
1114 size_t alloc;
1115 } git_atexit_hdlrs;
1116
1117 static int git_atexit_installed;
1118
1119 static void git_atexit_dispatch(void)
1120 {
1121 size_t i;
1122
1123 for (i=git_atexit_hdlrs.nr ; i ; i--)
1124 git_atexit_hdlrs.handlers[i-1]();
1125 }
1126
1127 static void git_atexit_clear(void)
1128 {
1129 free(git_atexit_hdlrs.handlers);
1130 memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
1131 git_atexit_installed = 0;
1132 }
1133
1134 #undef atexit
1135 int git_atexit(void (*handler)(void))
1136 {
1137 ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
1138 git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
1139 if (!git_atexit_installed) {
1140 if (atexit(&git_atexit_dispatch))
1141 return -1;
1142 git_atexit_installed = 1;
1143 }
1144 return 0;
1145 }
1146 #define atexit git_atexit
1147
1148 static int process_is_async;
1149 int in_async(void)
1150 {
1151 return process_is_async;
1152 }
1153
1154 static void NORETURN async_exit(int code)
1155 {
1156 exit(code);
1157 }
1158
1159 #endif
1160
1161 void check_pipe(int err)
1162 {
1163 if (err == EPIPE) {
1164 if (in_async())
1165 async_exit(141);
1166
1167 signal(SIGPIPE, SIG_DFL);
1168 raise(SIGPIPE);
1169 /* Should never happen, but just in case... */
1170 exit(141);
1171 }
1172 }
1173
1174 int start_async(struct async *async)
1175 {
1176 int need_in, need_out;
1177 int fdin[2], fdout[2];
1178 int proc_in, proc_out;
1179
1180 need_in = async->in < 0;
1181 if (need_in) {
1182 if (pipe(fdin) < 0) {
1183 if (async->out > 0)
1184 close(async->out);
1185 return error_errno("cannot create pipe");
1186 }
1187 async->in = fdin[1];
1188 }
1189
1190 need_out = async->out < 0;
1191 if (need_out) {
1192 if (pipe(fdout) < 0) {
1193 if (need_in)
1194 close_pair(fdin);
1195 else if (async->in)
1196 close(async->in);
1197 return error_errno("cannot create pipe");
1198 }
1199 async->out = fdout[0];
1200 }
1201
1202 if (need_in)
1203 proc_in = fdin[0];
1204 else if (async->in)
1205 proc_in = async->in;
1206 else
1207 proc_in = -1;
1208
1209 if (need_out)
1210 proc_out = fdout[1];
1211 else if (async->out)
1212 proc_out = async->out;
1213 else
1214 proc_out = -1;
1215
1216 #ifdef NO_PTHREADS
1217 /* Flush stdio before fork() to avoid cloning buffers */
1218 fflush(NULL);
1219
1220 async->pid = fork();
1221 if (async->pid < 0) {
1222 error_errno("fork (async) failed");
1223 goto error;
1224 }
1225 if (!async->pid) {
1226 if (need_in)
1227 close(fdin[1]);
1228 if (need_out)
1229 close(fdout[0]);
1230 git_atexit_clear();
1231 process_is_async = 1;
1232 exit(!!async->proc(proc_in, proc_out, async->data));
1233 }
1234
1235 mark_child_for_cleanup(async->pid, NULL);
1236
1237 if (need_in)
1238 close(fdin[0]);
1239 else if (async->in)
1240 close(async->in);
1241
1242 if (need_out)
1243 close(fdout[1]);
1244 else if (async->out)
1245 close(async->out);
1246 #else
1247 if (!main_thread_set) {
1248 /*
1249 * We assume that the first time that start_async is called
1250 * it is from the main thread.
1251 */
1252 main_thread_set = 1;
1253 main_thread = pthread_self();
1254 pthread_key_create(&async_key, NULL);
1255 pthread_key_create(&async_die_counter, NULL);
1256 set_die_routine(die_async);
1257 set_die_is_recursing_routine(async_die_is_recursing);
1258 }
1259
1260 if (proc_in >= 0)
1261 set_cloexec(proc_in);
1262 if (proc_out >= 0)
1263 set_cloexec(proc_out);
1264 async->proc_in = proc_in;
1265 async->proc_out = proc_out;
1266 {
1267 int err = pthread_create(&async->tid, NULL, run_thread, async);
1268 if (err) {
1269 error(_("cannot create async thread: %s"), strerror(err));
1270 goto error;
1271 }
1272 }
1273 #endif
1274 return 0;
1275
1276 error:
1277 if (need_in)
1278 close_pair(fdin);
1279 else if (async->in)
1280 close(async->in);
1281
1282 if (need_out)
1283 close_pair(fdout);
1284 else if (async->out)
1285 close(async->out);
1286 return -1;
1287 }
1288
1289 int finish_async(struct async *async)
1290 {
1291 #ifdef NO_PTHREADS
1292 return wait_or_whine(async->pid, "child process", 0);
1293 #else
1294 void *ret = (void *)(intptr_t)(-1);
1295
1296 if (pthread_join(async->tid, &ret))
1297 error("pthread_join failed");
1298 return (int)(intptr_t)ret;
1299 #endif
1300 }
1301
1302 int async_with_fork(void)
1303 {
1304 #ifdef NO_PTHREADS
1305 return 1;
1306 #else
1307 return 0;
1308 #endif
1309 }
1310
1311 const char *find_hook(const char *name)
1312 {
1313 static struct strbuf path = STRBUF_INIT;
1314
1315 strbuf_reset(&path);
1316 strbuf_git_path(&path, "hooks/%s", name);
1317 if (access(path.buf, X_OK) < 0) {
1318 int err = errno;
1319
1320 #ifdef STRIP_EXTENSION
1321 strbuf_addstr(&path, STRIP_EXTENSION);
1322 if (access(path.buf, X_OK) >= 0)
1323 return path.buf;
1324 if (errno == EACCES)
1325 err = errno;
1326 #endif
1327
1328 if (err == EACCES && advice_ignored_hook) {
1329 static struct string_list advise_given = STRING_LIST_INIT_DUP;
1330
1331 if (!string_list_lookup(&advise_given, name)) {
1332 string_list_insert(&advise_given, name);
1333 advise(_("The '%s' hook was ignored because "
1334 "it's not set as executable.\n"
1335 "You can disable this warning with "
1336 "`git config advice.ignoredHook false`."),
1337 path.buf);
1338 }
1339 }
1340 return NULL;
1341 }
1342 return path.buf;
1343 }
1344
1345 int run_hook_ve(const char *const *env, const char *name, va_list args)
1346 {
1347 struct child_process hook = CHILD_PROCESS_INIT;
1348 const char *p;
1349
1350 p = find_hook(name);
1351 if (!p)
1352 return 0;
1353
1354 argv_array_push(&hook.args, p);
1355 while ((p = va_arg(args, const char *)))
1356 argv_array_push(&hook.args, p);
1357 hook.env = env;
1358 hook.no_stdin = 1;
1359 hook.stdout_to_stderr = 1;
1360 hook.trace2_hook_name = name;
1361
1362 return run_command(&hook);
1363 }
1364
1365 int run_hook_le(const char *const *env, const char *name, ...)
1366 {
1367 va_list args;
1368 int ret;
1369
1370 va_start(args, name);
1371 ret = run_hook_ve(env, name, args);
1372 va_end(args);
1373
1374 return ret;
1375 }
1376
1377 struct io_pump {
1378 /* initialized by caller */
1379 int fd;
1380 int type; /* POLLOUT or POLLIN */
1381 union {
1382 struct {
1383 const char *buf;
1384 size_t len;
1385 } out;
1386 struct {
1387 struct strbuf *buf;
1388 size_t hint;
1389 } in;
1390 } u;
1391
1392 /* returned by pump_io */
1393 int error; /* 0 for success, otherwise errno */
1394
1395 /* internal use */
1396 struct pollfd *pfd;
1397 };
1398
1399 static int pump_io_round(struct io_pump *slots, int nr, struct pollfd *pfd)
1400 {
1401 int pollsize = 0;
1402 int i;
1403
1404 for (i = 0; i < nr; i++) {
1405 struct io_pump *io = &slots[i];
1406 if (io->fd < 0)
1407 continue;
1408 pfd[pollsize].fd = io->fd;
1409 pfd[pollsize].events = io->type;
1410 io->pfd = &pfd[pollsize++];
1411 }
1412
1413 if (!pollsize)
1414 return 0;
1415
1416 if (poll(pfd, pollsize, -1) < 0) {
1417 if (errno == EINTR)
1418 return 1;
1419 die_errno("poll failed");
1420 }
1421
1422 for (i = 0; i < nr; i++) {
1423 struct io_pump *io = &slots[i];
1424
1425 if (io->fd < 0)
1426 continue;
1427
1428 if (!(io->pfd->revents & (POLLOUT|POLLIN|POLLHUP|POLLERR|POLLNVAL)))
1429 continue;
1430
1431 if (io->type == POLLOUT) {
1432 ssize_t len = xwrite(io->fd,
1433 io->u.out.buf, io->u.out.len);
1434 if (len < 0) {
1435 io->error = errno;
1436 close(io->fd);
1437 io->fd = -1;
1438 } else {
1439 io->u.out.buf += len;
1440 io->u.out.len -= len;
1441 if (!io->u.out.len) {
1442 close(io->fd);
1443 io->fd = -1;
1444 }
1445 }
1446 }
1447
1448 if (io->type == POLLIN) {
1449 ssize_t len = strbuf_read_once(io->u.in.buf,
1450 io->fd, io->u.in.hint);
1451 if (len < 0)
1452 io->error = errno;
1453 if (len <= 0) {
1454 close(io->fd);
1455 io->fd = -1;
1456 }
1457 }
1458 }
1459
1460 return 1;
1461 }
1462
1463 static int pump_io(struct io_pump *slots, int nr)
1464 {
1465 struct pollfd *pfd;
1466 int i;
1467
1468 for (i = 0; i < nr; i++)
1469 slots[i].error = 0;
1470
1471 ALLOC_ARRAY(pfd, nr);
1472 while (pump_io_round(slots, nr, pfd))
1473 ; /* nothing */
1474 free(pfd);
1475
1476 /* There may be multiple errno values, so just pick the first. */
1477 for (i = 0; i < nr; i++) {
1478 if (slots[i].error) {
1479 errno = slots[i].error;
1480 return -1;
1481 }
1482 }
1483 return 0;
1484 }
1485
1486
1487 int pipe_command(struct child_process *cmd,
1488 const char *in, size_t in_len,
1489 struct strbuf *out, size_t out_hint,
1490 struct strbuf *err, size_t err_hint)
1491 {
1492 struct io_pump io[3];
1493 int nr = 0;
1494
1495 if (in)
1496 cmd->in = -1;
1497 if (out)
1498 cmd->out = -1;
1499 if (err)
1500 cmd->err = -1;
1501
1502 if (start_command(cmd) < 0)
1503 return -1;
1504
1505 if (in) {
1506 io[nr].fd = cmd->in;
1507 io[nr].type = POLLOUT;
1508 io[nr].u.out.buf = in;
1509 io[nr].u.out.len = in_len;
1510 nr++;
1511 }
1512 if (out) {
1513 io[nr].fd = cmd->out;
1514 io[nr].type = POLLIN;
1515 io[nr].u.in.buf = out;
1516 io[nr].u.in.hint = out_hint;
1517 nr++;
1518 }
1519 if (err) {
1520 io[nr].fd = cmd->err;
1521 io[nr].type = POLLIN;
1522 io[nr].u.in.buf = err;
1523 io[nr].u.in.hint = err_hint;
1524 nr++;
1525 }
1526
1527 if (pump_io(io, nr) < 0) {
1528 finish_command(cmd); /* throw away exit code */
1529 return -1;
1530 }
1531
1532 return finish_command(cmd);
1533 }
1534
1535 enum child_state {
1536 GIT_CP_FREE,
1537 GIT_CP_WORKING,
1538 GIT_CP_WAIT_CLEANUP,
1539 };
1540
1541 struct parallel_processes {
1542 void *data;
1543
1544 int max_processes;
1545 int nr_processes;
1546
1547 get_next_task_fn get_next_task;
1548 start_failure_fn start_failure;
1549 task_finished_fn task_finished;
1550
1551 struct {
1552 enum child_state state;
1553 struct child_process process;
1554 struct strbuf err;
1555 void *data;
1556 } *children;
1557 /*
1558 * The struct pollfd is logically part of *children,
1559 * but the system call expects it as its own array.
1560 */
1561 struct pollfd *pfd;
1562
1563 unsigned shutdown : 1;
1564
1565 int output_owner;
1566 struct strbuf buffered_output; /* of finished children */
1567 };
1568
1569 static int default_start_failure(struct strbuf *out,
1570 void *pp_cb,
1571 void *pp_task_cb)
1572 {
1573 return 0;
1574 }
1575
1576 static int default_task_finished(int result,
1577 struct strbuf *out,
1578 void *pp_cb,
1579 void *pp_task_cb)
1580 {
1581 return 0;
1582 }
1583
1584 static void kill_children(struct parallel_processes *pp, int signo)
1585 {
1586 int i, n = pp->max_processes;
1587
1588 for (i = 0; i < n; i++)
1589 if (pp->children[i].state == GIT_CP_WORKING)
1590 kill(pp->children[i].process.pid, signo);
1591 }
1592
1593 static struct parallel_processes *pp_for_signal;
1594
1595 static void handle_children_on_signal(int signo)
1596 {
1597 kill_children(pp_for_signal, signo);
1598 sigchain_pop(signo);
1599 raise(signo);
1600 }
1601
1602 static void pp_init(struct parallel_processes *pp,
1603 int n,
1604 get_next_task_fn get_next_task,
1605 start_failure_fn start_failure,
1606 task_finished_fn task_finished,
1607 void *data)
1608 {
1609 int i;
1610
1611 if (n < 1)
1612 n = online_cpus();
1613
1614 pp->max_processes = n;
1615
1616 trace_printf("run_processes_parallel: preparing to run up to %d tasks", n);
1617
1618 pp->data = data;
1619 if (!get_next_task)
1620 BUG("you need to specify a get_next_task function");
1621 pp->get_next_task = get_next_task;
1622
1623 pp->start_failure = start_failure ? start_failure : default_start_failure;
1624 pp->task_finished = task_finished ? task_finished : default_task_finished;
1625
1626 pp->nr_processes = 0;
1627 pp->output_owner = 0;
1628 pp->shutdown = 0;
1629 pp->children = xcalloc(n, sizeof(*pp->children));
1630 pp->pfd = xcalloc(n, sizeof(*pp->pfd));
1631 strbuf_init(&pp->buffered_output, 0);
1632
1633 for (i = 0; i < n; i++) {
1634 strbuf_init(&pp->children[i].err, 0);
1635 child_process_init(&pp->children[i].process);
1636 pp->pfd[i].events = POLLIN | POLLHUP;
1637 pp->pfd[i].fd = -1;
1638 }
1639
1640 pp_for_signal = pp;
1641 sigchain_push_common(handle_children_on_signal);
1642 }
1643
1644 static void pp_cleanup(struct parallel_processes *pp)
1645 {
1646 int i;
1647
1648 trace_printf("run_processes_parallel: done");
1649 for (i = 0; i < pp->max_processes; i++) {
1650 strbuf_release(&pp->children[i].err);
1651 child_process_clear(&pp->children[i].process);
1652 }
1653
1654 free(pp->children);
1655 free(pp->pfd);
1656
1657 /*
1658 * When get_next_task added messages to the buffer in its last
1659 * iteration, the buffered output is non empty.
1660 */
1661 strbuf_write(&pp->buffered_output, stderr);
1662 strbuf_release(&pp->buffered_output);
1663
1664 sigchain_pop_common();
1665 }
1666
1667 /* returns
1668 * 0 if a new task was started.
1669 * 1 if no new jobs was started (get_next_task ran out of work, non critical
1670 * problem with starting a new command)
1671 * <0 no new job was started, user wishes to shutdown early. Use negative code
1672 * to signal the children.
1673 */
1674 static int pp_start_one(struct parallel_processes *pp)
1675 {
1676 int i, code;
1677
1678 for (i = 0; i < pp->max_processes; i++)
1679 if (pp->children[i].state == GIT_CP_FREE)
1680 break;
1681 if (i == pp->max_processes)
1682 BUG("bookkeeping is hard");
1683
1684 code = pp->get_next_task(&pp->children[i].process,
1685 &pp->children[i].err,
1686 pp->data,
1687 &pp->children[i].data);
1688 if (!code) {
1689 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1690 strbuf_reset(&pp->children[i].err);
1691 return 1;
1692 }
1693 pp->children[i].process.err = -1;
1694 pp->children[i].process.stdout_to_stderr = 1;
1695 pp->children[i].process.no_stdin = 1;
1696
1697 if (start_command(&pp->children[i].process)) {
1698 code = pp->start_failure(&pp->children[i].err,
1699 pp->data,
1700 pp->children[i].data);
1701 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1702 strbuf_reset(&pp->children[i].err);
1703 if (code)
1704 pp->shutdown = 1;
1705 return code;
1706 }
1707
1708 pp->nr_processes++;
1709 pp->children[i].state = GIT_CP_WORKING;
1710 pp->pfd[i].fd = pp->children[i].process.err;
1711 return 0;
1712 }
1713
1714 static void pp_buffer_stderr(struct parallel_processes *pp, int output_timeout)
1715 {
1716 int i;
1717
1718 while ((i = poll(pp->pfd, pp->max_processes, output_timeout)) < 0) {
1719 if (errno == EINTR)
1720 continue;
1721 pp_cleanup(pp);
1722 die_errno("poll");
1723 }
1724
1725 /* Buffer output from all pipes. */
1726 for (i = 0; i < pp->max_processes; i++) {
1727 if (pp->children[i].state == GIT_CP_WORKING &&
1728 pp->pfd[i].revents & (POLLIN | POLLHUP)) {
1729 int n = strbuf_read_once(&pp->children[i].err,
1730 pp->children[i].process.err, 0);
1731 if (n == 0) {
1732 close(pp->children[i].process.err);
1733 pp->children[i].state = GIT_CP_WAIT_CLEANUP;
1734 } else if (n < 0)
1735 if (errno != EAGAIN)
1736 die_errno("read");
1737 }
1738 }
1739 }
1740
1741 static void pp_output(struct parallel_processes *pp)
1742 {
1743 int i = pp->output_owner;
1744 if (pp->children[i].state == GIT_CP_WORKING &&
1745 pp->children[i].err.len) {
1746 strbuf_write(&pp->children[i].err, stderr);
1747 strbuf_reset(&pp->children[i].err);
1748 }
1749 }
1750
1751 static int pp_collect_finished(struct parallel_processes *pp)
1752 {
1753 int i, code;
1754 int n = pp->max_processes;
1755 int result = 0;
1756
1757 while (pp->nr_processes > 0) {
1758 for (i = 0; i < pp->max_processes; i++)
1759 if (pp->children[i].state == GIT_CP_WAIT_CLEANUP)
1760 break;
1761 if (i == pp->max_processes)
1762 break;
1763
1764 code = finish_command(&pp->children[i].process);
1765
1766 code = pp->task_finished(code,
1767 &pp->children[i].err, pp->data,
1768 pp->children[i].data);
1769
1770 if (code)
1771 result = code;
1772 if (code < 0)
1773 break;
1774
1775 pp->nr_processes--;
1776 pp->children[i].state = GIT_CP_FREE;
1777 pp->pfd[i].fd = -1;
1778 child_process_init(&pp->children[i].process);
1779
1780 if (i != pp->output_owner) {
1781 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1782 strbuf_reset(&pp->children[i].err);
1783 } else {
1784 strbuf_write(&pp->children[i].err, stderr);
1785 strbuf_reset(&pp->children[i].err);
1786
1787 /* Output all other finished child processes */
1788 strbuf_write(&pp->buffered_output, stderr);
1789 strbuf_reset(&pp->buffered_output);
1790
1791 /*
1792 * Pick next process to output live.
1793 * NEEDSWORK:
1794 * For now we pick it randomly by doing a round
1795 * robin. Later we may want to pick the one with
1796 * the most output or the longest or shortest
1797 * running process time.
1798 */
1799 for (i = 0; i < n; i++)
1800 if (pp->children[(pp->output_owner + i) % n].state == GIT_CP_WORKING)
1801 break;
1802 pp->output_owner = (pp->output_owner + i) % n;
1803 }
1804 }
1805 return result;
1806 }
1807
1808 int run_processes_parallel(int n,
1809 get_next_task_fn get_next_task,
1810 start_failure_fn start_failure,
1811 task_finished_fn task_finished,
1812 void *pp_cb)
1813 {
1814 int i, code;
1815 int output_timeout = 100;
1816 int spawn_cap = 4;
1817 struct parallel_processes pp;
1818
1819 pp_init(&pp, n, get_next_task, start_failure, task_finished, pp_cb);
1820 while (1) {
1821 for (i = 0;
1822 i < spawn_cap && !pp.shutdown &&
1823 pp.nr_processes < pp.max_processes;
1824 i++) {
1825 code = pp_start_one(&pp);
1826 if (!code)
1827 continue;
1828 if (code < 0) {
1829 pp.shutdown = 1;
1830 kill_children(&pp, -code);
1831 }
1832 break;
1833 }
1834 if (!pp.nr_processes)
1835 break;
1836 pp_buffer_stderr(&pp, output_timeout);
1837 pp_output(&pp);
1838 code = pp_collect_finished(&pp);
1839 if (code) {
1840 pp.shutdown = 1;
1841 if (code < 0)
1842 kill_children(&pp, -code);
1843 }
1844 }
1845
1846 pp_cleanup(&pp);
1847 return 0;
1848 }
1849
1850 int run_processes_parallel_tr2(int n, get_next_task_fn get_next_task,
1851 start_failure_fn start_failure,
1852 task_finished_fn task_finished, void *pp_cb,
1853 const char *tr2_category, const char *tr2_label)
1854 {
1855 int result;
1856
1857 trace2_region_enter_printf(tr2_category, tr2_label, NULL, "max:%d",
1858 ((n < 1) ? online_cpus() : n));
1859
1860 result = run_processes_parallel(n, get_next_task, start_failure,
1861 task_finished, pp_cb);
1862
1863 trace2_region_leave(tr2_category, tr2_label, NULL);
1864
1865 return result;
1866 }