run-command.c: print program 'git' when tracing git_cmd mode
[git/git.git] / run-command.c
CommitLineData
b1bf95bb
JW
1#include "cache.h"
2#include "run-command.h"
77cb17e9 3#include "exec_cmd.h"
afe19ff7 4#include "sigchain.h"
5d40a179 5#include "argv-array.h"
c553c72e
SB
6#include "thread-utils.h"
7#include "strbuf.h"
f805a00a 8#include "string-list.h"
e73dd786 9#include "quote.h"
b1bf95bb 10
483bbd4e
RS
11void child_process_init(struct child_process *child)
12{
13 memset(child, 0, sizeof(*child));
14 argv_array_init(&child->args);
19a583dc 15 argv_array_init(&child->env_array);
483bbd4e
RS
16}
17
2d71608e
RS
18void child_process_clear(struct child_process *child)
19{
20 argv_array_clear(&child->args);
21 argv_array_clear(&child->env_array);
22}
23
afe19ff7
JK
24struct child_to_clean {
25 pid_t pid;
ac2fbaa6 26 struct child_process *process;
afe19ff7
JK
27 struct child_to_clean *next;
28};
29static struct child_to_clean *children_to_clean;
30static int installed_child_cleanup_handler;
31
507d7804 32static void cleanup_children(int sig, int in_signal)
afe19ff7 33{
46df6906
JK
34 struct child_to_clean *children_to_wait_for = NULL;
35
afe19ff7
JK
36 while (children_to_clean) {
37 struct child_to_clean *p = children_to_clean;
38 children_to_clean = p->next;
ac2fbaa6
LS
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
afe19ff7 51 kill(p->pid, sig);
46df6906 52
7b91929b 53 if (p->process && p->process->wait_after_clean) {
46df6906
JK
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
507d7804
TI
69 if (!in_signal)
70 free(p);
afe19ff7
JK
71 }
72}
73
74static void cleanup_children_on_signal(int sig)
75{
507d7804 76 cleanup_children(sig, 1);
afe19ff7
JK
77 sigchain_pop(sig);
78 raise(sig);
79}
80
81static void cleanup_children_on_exit(void)
82{
507d7804 83 cleanup_children(SIGTERM, 0);
afe19ff7
JK
84}
85
ac2fbaa6 86static void mark_child_for_cleanup(pid_t pid, struct child_process *process)
afe19ff7
JK
87{
88 struct child_to_clean *p = xmalloc(sizeof(*p));
89 p->pid = pid;
ac2fbaa6 90 p->process = process;
afe19ff7
JK
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
101static void clear_child_for_cleanup(pid_t pid)
102{
bdee397d 103 struct child_to_clean **pp;
afe19ff7 104
bdee397d
DG
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);
afe19ff7
JK
111 return;
112 }
113 }
114}
115
9dc09c76
SP
116static inline void close_pair(int fd[2])
117{
118 close(fd[0]);
119 close(fd[1]);
120}
121
38124a40
BW
122int 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
94028310
BW
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 */
38f865c2
JK
181static 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
94028310 201 if (is_executable(buf.buf))
38f865c2
JK
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
213static int exists_in_PATH(const char *file)
214{
215 char *r = locate_in_PATH(file);
216 free(r);
217 return r != NULL;
218}
219
220int sane_execvp(const char *file, char * const argv[])
221{
222 if (!execvp(file, argv))
223 return 0; /* cannot happen ;-) */
224
225 /*
226 * When a command can't be found because one of the directories
227 * listed in $PATH is unsearchable, execvp reports EACCES, but
228 * careful usability testing (read: analysis of occasional bug
229 * reports) reveals that "No such file or directory" is more
230 * intuitive.
231 *
232 * We avoid commands with "/", because execvp will not do $PATH
233 * lookups in that case.
234 *
235 * The reassignment of EACCES to errno looks like a no-op below,
236 * but we need to protect against exists_in_PATH overwriting errno.
237 */
238 if (errno == EACCES && !strchr(file, '/'))
239 errno = exists_in_PATH(file) ? EACCES : ENOENT;
a7855083
JH
240 else if (errno == ENOTDIR && !strchr(file, '/'))
241 errno = ENOENT;
38f865c2
JK
242 return -1;
243}
244
20574f55 245static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
8dba1e63 246{
20574f55 247 if (!argv[0])
8dba1e63
JK
248 die("BUG: shell command is empty");
249
f445644f 250 if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
380395d0 251#ifndef GIT_WINDOWS_NATIVE
20574f55 252 argv_array_push(out, SHELL_PATH);
77629754 253#else
20574f55 254 argv_array_push(out, "sh");
77629754 255#endif
20574f55 256 argv_array_push(out, "-c");
8dba1e63 257
20574f55
JK
258 /*
259 * If we have no extra arguments, we do not even need to
260 * bother with the "$@" magic.
261 */
262 if (!argv[1])
263 argv_array_push(out, argv[0]);
264 else
265 argv_array_pushf(out, "%s \"$@\"", argv[0]);
266 }
8dba1e63 267
20574f55
JK
268 argv_array_pushv(out, argv);
269 return out->argv;
8dba1e63
JK
270}
271
380395d0 272#ifndef GIT_WINDOWS_NATIVE
2b541bf8
JS
273static int child_notifier = -1;
274
79319b19
BW
275enum child_errcode {
276 CHILD_ERR_CHDIR,
53fa6753
BW
277 CHILD_ERR_DUP2,
278 CHILD_ERR_CLOSE,
45afb1ca 279 CHILD_ERR_SIGPROCMASK,
79319b19
BW
280 CHILD_ERR_ENOENT,
281 CHILD_ERR_SILENT,
282 CHILD_ERR_ERRNO
283};
284
285struct child_err {
286 enum child_errcode err;
287 int syserr; /* errno */
288};
289
290static void child_die(enum child_errcode err)
2b541bf8 291{
79319b19
BW
292 struct child_err buf;
293
294 buf.err = err;
295 buf.syserr = errno;
296
297 /* write(2) on buf smaller than PIPE_BUF (min 512) is atomic: */
298 xwrite(child_notifier, &buf, sizeof(buf));
299 _exit(1);
300}
301
53fa6753
BW
302static void child_dup2(int fd, int to)
303{
304 if (dup2(fd, to) < 0)
305 child_die(CHILD_ERR_DUP2);
306}
307
308static void child_close(int fd)
309{
310 if (close(fd))
311 child_die(CHILD_ERR_CLOSE);
312}
313
314static void child_close_pair(int fd[2])
315{
316 child_close(fd[0]);
317 child_close(fd[1]);
318}
319
79319b19
BW
320/*
321 * parent will make it look like the child spewed a fatal error and died
322 * this is needed to prevent changes to t0061.
323 */
324static void fake_fatal(const char *err, va_list params)
325{
326 vreportf("fatal: ", err, params);
327}
328
329static void child_error_fn(const char *err, va_list params)
330{
331 const char msg[] = "error() should not be called in child\n";
332 xwrite(2, msg, sizeof(msg) - 1);
333}
334
335static void child_warn_fn(const char *err, va_list params)
336{
337 const char msg[] = "warn() should not be called in child\n";
338 xwrite(2, msg, sizeof(msg) - 1);
339}
340
341static void NORETURN child_die_fn(const char *err, va_list params)
342{
343 const char msg[] = "die() should not be called in child\n";
344 xwrite(2, msg, sizeof(msg) - 1);
345 _exit(2);
346}
347
348/* this runs in the parent process */
349static void child_err_spew(struct child_process *cmd, struct child_err *cerr)
350{
351 static void (*old_errfn)(const char *err, va_list params);
352
353 old_errfn = get_error_routine();
354 set_error_routine(fake_fatal);
355 errno = cerr->syserr;
356
357 switch (cerr->err) {
358 case CHILD_ERR_CHDIR:
359 error_errno("exec '%s': cd to '%s' failed",
360 cmd->argv[0], cmd->dir);
361 break;
53fa6753
BW
362 case CHILD_ERR_DUP2:
363 error_errno("dup2() in child failed");
364 break;
365 case CHILD_ERR_CLOSE:
366 error_errno("close() in child failed");
367 break;
45afb1ca
EW
368 case CHILD_ERR_SIGPROCMASK:
369 error_errno("sigprocmask failed restoring signals");
370 break;
79319b19
BW
371 case CHILD_ERR_ENOENT:
372 error_errno("cannot run %s", cmd->argv[0]);
373 break;
374 case CHILD_ERR_SILENT:
375 break;
376 case CHILD_ERR_ERRNO:
377 error_errno("cannot exec '%s'", cmd->argv[0]);
378 break;
379 }
380 set_error_routine(old_errfn);
2b541bf8 381}
3967e25b
BW
382
383static void prepare_cmd(struct argv_array *out, const struct child_process *cmd)
384{
385 if (!cmd->argv[0])
386 die("BUG: command is empty");
387
e3a43446
BW
388 /*
389 * Add SHELL_PATH so in the event exec fails with ENOEXEC we can
390 * attempt to interpret the command with 'sh'.
391 */
392 argv_array_push(out, SHELL_PATH);
393
3967e25b
BW
394 if (cmd->git_cmd) {
395 argv_array_push(out, "git");
396 argv_array_pushv(out, cmd->argv);
397 } else if (cmd->use_shell) {
398 prepare_shell_cmd(out, cmd->argv);
399 } else {
400 argv_array_pushv(out, cmd->argv);
401 }
e3a43446
BW
402
403 /*
404 * If there are no '/' characters in the command then perform a path
405 * lookup and use the resolved path as the command to exec. If there
406 * are no '/' characters or if the command wasn't found in the path,
407 * have exec attempt to invoke the command directly.
408 */
409 if (!strchr(out->argv[1], '/')) {
410 char *program = locate_in_PATH(out->argv[1]);
411 if (program) {
412 free((char *)out->argv[1]);
413 out->argv[1] = program;
414 }
415 }
3967e25b 416}
ae25394b
BW
417
418static char **prep_childenv(const char *const *deltaenv)
419{
420 extern char **environ;
421 char **childenv;
422 struct string_list env = STRING_LIST_INIT_DUP;
423 struct strbuf key = STRBUF_INIT;
424 const char *const *p;
425 int i;
426
427 /* Construct a sorted string list consisting of the current environ */
428 for (p = (const char *const *) environ; p && *p; p++) {
429 const char *equals = strchr(*p, '=');
430
431 if (equals) {
432 strbuf_reset(&key);
433 strbuf_add(&key, *p, equals - *p);
434 string_list_append(&env, key.buf)->util = (void *) *p;
435 } else {
436 string_list_append(&env, *p)->util = (void *) *p;
437 }
438 }
439 string_list_sort(&env);
440
441 /* Merge in 'deltaenv' with the current environ */
442 for (p = deltaenv; p && *p; p++) {
443 const char *equals = strchr(*p, '=');
444
445 if (equals) {
446 /* ('key=value'), insert or replace entry */
447 strbuf_reset(&key);
448 strbuf_add(&key, *p, equals - *p);
449 string_list_insert(&env, key.buf)->util = (void *) *p;
450 } else {
451 /* otherwise ('key') remove existing entry */
452 string_list_remove(&env, *p, 0);
453 }
454 }
455
456 /* Create an array of 'char *' to be used as the childenv */
0e187d75 457 ALLOC_ARRAY(childenv, env.nr + 1);
ae25394b
BW
458 for (i = 0; i < env.nr; i++)
459 childenv[i] = env.items[i].util;
460 childenv[env.nr] = NULL;
461
462 string_list_clear(&env, 0);
463 strbuf_release(&key);
464 return childenv;
465}
45afb1ca
EW
466
467struct atfork_state {
468#ifndef NO_PTHREADS
469 int cs;
470#endif
471 sigset_t old;
472};
473
474#ifndef NO_PTHREADS
475static void bug_die(int err, const char *msg)
476{
477 if (err) {
478 errno = err;
479 die_errno("BUG: %s", msg);
480 }
481}
482#endif
483
484static void atfork_prepare(struct atfork_state *as)
485{
486 sigset_t all;
487
488 if (sigfillset(&all))
489 die_errno("sigfillset");
490#ifdef NO_PTHREADS
491 if (sigprocmask(SIG_SETMASK, &all, &as->old))
492 die_errno("sigprocmask");
493#else
494 bug_die(pthread_sigmask(SIG_SETMASK, &all, &as->old),
495 "blocking all signals");
496 bug_die(pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &as->cs),
497 "disabling cancellation");
498#endif
499}
500
501static void atfork_parent(struct atfork_state *as)
502{
503#ifdef NO_PTHREADS
504 if (sigprocmask(SIG_SETMASK, &as->old, NULL))
505 die_errno("sigprocmask");
506#else
507 bug_die(pthread_setcancelstate(as->cs, NULL),
508 "re-enabling cancellation");
509 bug_die(pthread_sigmask(SIG_SETMASK, &as->old, NULL),
510 "restoring signal mask");
200a76b7 511#endif
45afb1ca
EW
512}
513#endif /* GIT_WINDOWS_NATIVE */
a5487ddf
JS
514
515static inline void set_cloexec(int fd)
516{
517 int flags = fcntl(fd, F_GETFD);
518 if (flags >= 0)
519 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
520}
a5487ddf 521
507d7804 522static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
ab0b41da
JS
523{
524 int status, code = -1;
525 pid_t waiting;
526 int failed_errno = 0;
527
528 while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
529 ; /* nothing */
507d7804
TI
530 if (in_signal)
531 return 0;
ab0b41da
JS
532
533 if (waiting < 0) {
534 failed_errno = errno;
fbcb0e06 535 error_errno("waitpid for %s failed", argv0);
ab0b41da
JS
536 } else if (waiting != pid) {
537 error("waitpid is confused (%s)", argv0);
538 } else if (WIFSIGNALED(status)) {
539 code = WTERMSIG(status);
ac78663b 540 if (code != SIGINT && code != SIGQUIT && code != SIGPIPE)
a2767c5c 541 error("%s died of signal %d", argv0, code);
ab0b41da
JS
542 /*
543 * This return value is chosen so that code & 0xff
544 * mimics the exit code that a POSIX shell would report for
545 * a program that died from this signal.
546 */
709ca730 547 code += 128;
ab0b41da
JS
548 } else if (WIFEXITED(status)) {
549 code = WEXITSTATUS(status);
ab0b41da
JS
550 } else {
551 error("waitpid is confused (%s)", argv0);
552 }
afe19ff7
JK
553
554 clear_child_for_cleanup(pid);
555
ab0b41da
JS
556 errno = failed_errno;
557 return code;
558}
559
e73dd786
NTND
560static void trace_run_command(const struct child_process *cp)
561{
562 struct strbuf buf = STRBUF_INIT;
563
564 if (!trace_want(&trace_default_key))
565 return;
566
567 strbuf_addf(&buf, "trace: run_command:");
21dfc5e0
NTND
568 if (cp->git_cmd)
569 strbuf_addstr(&buf, " git");
e73dd786
NTND
570 sq_quote_argv_pretty(&buf, cp->argv);
571
572 trace_printf("%s", buf.buf);
573 strbuf_release(&buf);
574}
575
ebcb5d16 576int start_command(struct child_process *cmd)
b1bf95bb 577{
f3b33f1d
JS
578 int need_in, need_out, need_err;
579 int fdin[2], fdout[2], fderr[2];
25043d8a 580 int failed_errno;
939296c4 581 char *str;
4919bf03 582
c460c0ec
JK
583 if (!cmd->argv)
584 cmd->argv = cmd->args.argv;
19a583dc
RS
585 if (!cmd->env)
586 cmd->env = cmd->env_array.argv;
c460c0ec 587
c20181e3
JS
588 /*
589 * In case of errors we must keep the promise to close FDs
590 * that have been passed in via ->in and ->out.
591 */
592
e4507ae8 593 need_in = !cmd->no_stdin && cmd->in < 0;
4919bf03 594 if (need_in) {
c20181e3 595 if (pipe(fdin) < 0) {
0ac77ec3 596 failed_errno = errno;
c20181e3
JS
597 if (cmd->out > 0)
598 close(cmd->out);
939296c4 599 str = "standard input";
0ac77ec3 600 goto fail_pipe;
c20181e3 601 }
4919bf03 602 cmd->in = fdin[1];
4919bf03
SP
603 }
604
e4507ae8
SP
605 need_out = !cmd->no_stdout
606 && !cmd->stdout_to_stderr
607 && cmd->out < 0;
f4bba25b
SP
608 if (need_out) {
609 if (pipe(fdout) < 0) {
0ac77ec3 610 failed_errno = errno;
f4bba25b
SP
611 if (need_in)
612 close_pair(fdin);
c20181e3
JS
613 else if (cmd->in)
614 close(cmd->in);
939296c4 615 str = "standard output";
0ac77ec3 616 goto fail_pipe;
f4bba25b
SP
617 }
618 cmd->out = fdout[0];
f4bba25b
SP
619 }
620
b73a4397 621 need_err = !cmd->no_stderr && cmd->err < 0;
f3b33f1d
JS
622 if (need_err) {
623 if (pipe(fderr) < 0) {
0ac77ec3 624 failed_errno = errno;
f3b33f1d
JS
625 if (need_in)
626 close_pair(fdin);
c20181e3
JS
627 else if (cmd->in)
628 close(cmd->in);
f3b33f1d
JS
629 if (need_out)
630 close_pair(fdout);
c20181e3
JS
631 else if (cmd->out)
632 close(cmd->out);
939296c4 633 str = "standard error";
0ac77ec3 634fail_pipe:
939296c4
SB
635 error("cannot create %s pipe for %s: %s",
636 str, cmd->argv[0], strerror(failed_errno));
2d71608e 637 child_process_clear(cmd);
0ac77ec3
JS
638 errno = failed_errno;
639 return -1;
f3b33f1d
JS
640 }
641 cmd->err = fderr[0];
642 }
643
e73dd786
NTND
644 trace_run_command(cmd);
645
13af8cbd 646 fflush(NULL);
8852f5d7 647
380395d0 648#ifndef GIT_WINDOWS_NATIVE
2b541bf8
JS
649{
650 int notify_pipe[2];
db015a28 651 int null_fd = -1;
ae25394b 652 char **childenv;
3967e25b 653 struct argv_array argv = ARGV_ARRAY_INIT;
79319b19 654 struct child_err cerr;
45afb1ca 655 struct atfork_state as;
3967e25b 656
2b541bf8
JS
657 if (pipe(notify_pipe))
658 notify_pipe[0] = notify_pipe[1] = -1;
659
db015a28
BW
660 if (cmd->no_stdin || cmd->no_stdout || cmd->no_stderr) {
661 null_fd = open("/dev/null", O_RDWR | O_CLOEXEC);
662 if (null_fd < 0)
663 die_errno(_("open /dev/null failed"));
664 set_cloexec(null_fd);
665 }
666
3967e25b 667 prepare_cmd(&argv, cmd);
ae25394b 668 childenv = prep_childenv(cmd->env);
45afb1ca 669 atfork_prepare(&as);
3967e25b 670
e503cd6e
BW
671 /*
672 * NOTE: In order to prevent deadlocking when using threads special
673 * care should be taken with the function calls made in between the
674 * fork() and exec() calls. No calls should be made to functions which
675 * require acquiring a lock (e.g. malloc) as the lock could have been
676 * held by another thread at the time of forking, causing the lock to
677 * never be released in the child process. This means only
678 * Async-Signal-Safe functions are permitted in the child.
679 */
ebcb5d16 680 cmd->pid = fork();
25043d8a 681 failed_errno = errno;
ebcb5d16 682 if (!cmd->pid) {
45afb1ca 683 int sig;
a5487ddf 684 /*
79319b19
BW
685 * Ensure the default die/error/warn routines do not get
686 * called, they can take stdio locks and malloc.
a5487ddf 687 */
79319b19
BW
688 set_die_routine(child_die_fn);
689 set_error_routine(child_error_fn);
690 set_warn_routine(child_warn_fn);
a5487ddf 691
2b541bf8
JS
692 close(notify_pipe[0]);
693 set_cloexec(notify_pipe[1]);
694 child_notifier = notify_pipe[1];
2b541bf8 695
e4507ae8 696 if (cmd->no_stdin)
53fa6753 697 child_dup2(null_fd, 0);
e4507ae8 698 else if (need_in) {
53fa6753
BW
699 child_dup2(fdin[0], 0);
700 child_close_pair(fdin);
4919bf03 701 } else if (cmd->in) {
53fa6753
BW
702 child_dup2(cmd->in, 0);
703 child_close(cmd->in);
95d3c4f5 704 }
4919bf03 705
ce2cf27a 706 if (cmd->no_stderr)
53fa6753 707 child_dup2(null_fd, 2);
ce2cf27a 708 else if (need_err) {
53fa6753
BW
709 child_dup2(fderr[1], 2);
710 child_close_pair(fderr);
4f41b611 711 } else if (cmd->err > 1) {
53fa6753
BW
712 child_dup2(cmd->err, 2);
713 child_close(cmd->err);
ce2cf27a
CC
714 }
715
e4507ae8 716 if (cmd->no_stdout)
53fa6753 717 child_dup2(null_fd, 1);
e4507ae8 718 else if (cmd->stdout_to_stderr)
53fa6753 719 child_dup2(2, 1);
f4bba25b 720 else if (need_out) {
53fa6753
BW
721 child_dup2(fdout[1], 1);
722 child_close_pair(fdout);
f4bba25b 723 } else if (cmd->out > 1) {
53fa6753
BW
724 child_dup2(cmd->out, 1);
725 child_close(cmd->out);
f4bba25b
SP
726 }
727
1568fea0 728 if (cmd->dir && chdir(cmd->dir))
79319b19 729 child_die(CHILD_ERR_CHDIR);
3967e25b 730
45afb1ca
EW
731 /*
732 * restore default signal handlers here, in case
733 * we catch a signal right before execve below
734 */
735 for (sig = 1; sig < NSIG; sig++) {
736 /* ignored signals get reset to SIG_DFL on execve */
737 if (signal(sig, SIG_DFL) == SIG_IGN)
738 signal(sig, SIG_IGN);
739 }
740
741 if (sigprocmask(SIG_SETMASK, &as.old, NULL) != 0)
742 child_die(CHILD_ERR_SIGPROCMASK);
743
e3a43446
BW
744 /*
745 * Attempt to exec using the command and arguments starting at
746 * argv.argv[1]. argv.argv[0] contains SHELL_PATH which will
747 * be used in the event exec failed with ENOEXEC at which point
748 * we will try to interpret the command using 'sh'.
749 */
ae25394b
BW
750 execve(argv.argv[1], (char *const *) argv.argv + 1,
751 (char *const *) childenv);
e3a43446 752 if (errno == ENOEXEC)
ae25394b
BW
753 execve(argv.argv[0], (char *const *) argv.argv,
754 (char *const *) childenv);
3967e25b 755
fc1b56f0 756 if (errno == ENOENT) {
79319b19
BW
757 if (cmd->silent_exec_failure)
758 child_die(CHILD_ERR_SILENT);
759 child_die(CHILD_ERR_ENOENT);
fc1b56f0 760 } else {
79319b19 761 child_die(CHILD_ERR_ERRNO);
fc1b56f0 762 }
b1bf95bb 763 }
45afb1ca 764 atfork_parent(&as);
0ac77ec3 765 if (cmd->pid < 0)
fbcb0e06 766 error_errno("cannot fork() for %s", cmd->argv[0]);
afe19ff7 767 else if (cmd->clean_on_exit)
ac2fbaa6 768 mark_child_for_cleanup(cmd->pid, cmd);
2b541bf8
JS
769
770 /*
3967e25b 771 * Wait for child's exec. If the exec succeeds (or if fork()
2b541bf8 772 * failed), EOF is seen immediately by the parent. Otherwise, the
79319b19 773 * child process sends a child_err struct.
2b541bf8
JS
774 * Note that use of this infrastructure is completely advisory,
775 * therefore, we keep error checks minimal.
776 */
777 close(notify_pipe[1]);
79319b19 778 if (xread(notify_pipe[0], &cerr, sizeof(cerr)) == sizeof(cerr)) {
2b541bf8 779 /*
3967e25b 780 * At this point we know that fork() succeeded, but exec()
2b541bf8
JS
781 * failed. Errors have been reported to our stderr.
782 */
507d7804 783 wait_or_whine(cmd->pid, cmd->argv[0], 0);
79319b19 784 child_err_spew(cmd, &cerr);
2b541bf8
JS
785 failed_errno = errno;
786 cmd->pid = -1;
787 }
788 close(notify_pipe[0]);
3967e25b 789
db015a28
BW
790 if (null_fd >= 0)
791 close(null_fd);
3967e25b 792 argv_array_clear(&argv);
ae25394b 793 free(childenv);
2b541bf8 794}
ba26f296 795#else
0d30ad71 796{
75301f90 797 int fhin = 0, fhout = 1, fherr = 2;
108ac313 798 const char **sargv = cmd->argv;
20574f55 799 struct argv_array nargv = ARGV_ARRAY_INIT;
ba26f296 800
75301f90
JS
801 if (cmd->no_stdin)
802 fhin = open("/dev/null", O_RDWR);
803 else if (need_in)
804 fhin = dup(fdin[0]);
805 else if (cmd->in)
806 fhin = dup(cmd->in);
807
808 if (cmd->no_stderr)
809 fherr = open("/dev/null", O_RDWR);
810 else if (need_err)
811 fherr = dup(fderr[1]);
76d44c8c
JH
812 else if (cmd->err > 2)
813 fherr = dup(cmd->err);
75301f90
JS
814
815 if (cmd->no_stdout)
816 fhout = open("/dev/null", O_RDWR);
817 else if (cmd->stdout_to_stderr)
818 fhout = dup(fherr);
819 else if (need_out)
820 fhout = dup(fdout[1]);
821 else if (cmd->out > 1)
822 fhout = dup(cmd->out);
ba26f296 823
5a50085c 824 if (cmd->git_cmd)
20574f55 825 cmd->argv = prepare_git_cmd(&nargv, cmd->argv);
5a50085c 826 else if (cmd->use_shell)
20574f55 827 cmd->argv = prepare_shell_cmd(&nargv, cmd->argv);
ba26f296 828
77734da2
KB
829 cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
830 cmd->dir, fhin, fhout, fherr);
0ac77ec3 831 failed_errno = errno;
c024beb5 832 if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
fbcb0e06 833 error_errno("cannot spawn %s", cmd->argv[0]);
afe19ff7 834 if (cmd->clean_on_exit && cmd->pid >= 0)
ac2fbaa6 835 mark_child_for_cleanup(cmd->pid, cmd);
ba26f296 836
20574f55 837 argv_array_clear(&nargv);
108ac313 838 cmd->argv = sargv;
75301f90
JS
839 if (fhin != 0)
840 close(fhin);
841 if (fhout != 1)
842 close(fhout);
843 if (fherr != 2)
844 close(fherr);
0d30ad71 845}
ba26f296
JS
846#endif
847
848 if (cmd->pid < 0) {
849 if (need_in)
850 close_pair(fdin);
851 else if (cmd->in)
852 close(cmd->in);
853 if (need_out)
854 close_pair(fdout);
855 else if (cmd->out)
856 close(cmd->out);
857 if (need_err)
858 close_pair(fderr);
fc012c28
D
859 else if (cmd->err)
860 close(cmd->err);
2d71608e 861 child_process_clear(cmd);
0ac77ec3
JS
862 errno = failed_errno;
863 return -1;
ba26f296 864 }
4919bf03
SP
865
866 if (need_in)
867 close(fdin[0]);
868 else if (cmd->in)
869 close(cmd->in);
870
f4bba25b
SP
871 if (need_out)
872 close(fdout[1]);
c20181e3 873 else if (cmd->out)
f4bba25b
SP
874 close(cmd->out);
875
f3b33f1d
JS
876 if (need_err)
877 close(fderr[1]);
4f41b611
SP
878 else if (cmd->err)
879 close(cmd->err);
f3b33f1d 880
ebcb5d16
SP
881 return 0;
882}
883
2d22c208
JS
884int finish_command(struct child_process *cmd)
885{
507d7804 886 int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
2d71608e 887 child_process_clear(cmd);
c460c0ec 888 return ret;
2d22c208
JS
889}
890
507d7804
TI
891int finish_command_in_signal(struct child_process *cmd)
892{
893 return wait_or_whine(cmd->pid, cmd->argv[0], 1);
894}
895
896
ebcb5d16
SP
897int run_command(struct child_process *cmd)
898{
c29b3962
JK
899 int code;
900
901 if (cmd->out < 0 || cmd->err < 0)
902 die("BUG: run_command with a pipe can cause deadlock");
903
904 code = start_command(cmd);
ebcb5d16
SP
905 if (code)
906 return code;
907 return finish_command(cmd);
908}
909
f1000898
SP
910int run_command_v_opt(const char **argv, int opt)
911{
41e9bad7 912 return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
1568fea0
AR
913}
914
ee493148
AR
915int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
916{
1f87293d
RS
917 struct child_process cmd = CHILD_PROCESS_INIT;
918 cmd.argv = argv;
919 cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
920 cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
921 cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
922 cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
923 cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
924 cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
ee493148
AR
925 cmd.dir = dir;
926 cmd.env = env;
927 return run_command(&cmd);
928}
2d22c208 929
f6b60983 930#ifndef NO_PTHREADS
0ea1c89b
JS
931static pthread_t main_thread;
932static int main_thread_set;
933static pthread_key_t async_key;
1ece66bc 934static pthread_key_t async_die_counter;
0ea1c89b 935
200a76b7 936static void *run_thread(void *data)
618ebe9f
JS
937{
938 struct async *async = data;
f6b60983 939 intptr_t ret;
0ea1c89b 940
c792d7b6
JK
941 if (async->isolate_sigpipe) {
942 sigset_t mask;
943 sigemptyset(&mask);
944 sigaddset(&mask, SIGPIPE);
945 if (pthread_sigmask(SIG_BLOCK, &mask, NULL) < 0) {
946 ret = error("unable to block SIGPIPE in async thread");
947 return (void *)ret;
948 }
949 }
950
0ea1c89b 951 pthread_setspecific(async_key, async);
f6b60983 952 ret = async->proc(async->proc_in, async->proc_out, async->data);
200a76b7 953 return (void *)ret;
618ebe9f 954}
0ea1c89b
JS
955
956static NORETURN void die_async(const char *err, va_list params)
957{
958 vreportf("fatal: ", err, params);
959
661a8cf4 960 if (in_async()) {
0ea1c89b
JS
961 struct async *async = pthread_getspecific(async_key);
962 if (async->proc_in >= 0)
963 close(async->proc_in);
964 if (async->proc_out >= 0)
965 close(async->proc_out);
966 pthread_exit((void *)128);
967 }
968
969 exit(128);
618ebe9f 970}
1ece66bc
JK
971
972static int async_die_is_recursing(void)
973{
974 void *ret = pthread_getspecific(async_die_counter);
975 pthread_setspecific(async_die_counter, (void *)1);
976 return ret != NULL;
977}
978
661a8cf4
JK
979int in_async(void)
980{
981 if (!main_thread_set)
982 return 0; /* no asyncs started yet */
983 return !pthread_equal(main_thread, pthread_self());
984}
985
b992fe10 986static void NORETURN async_exit(int code)
9658846c
JK
987{
988 pthread_exit((void *)(intptr_t)code);
989}
990
0f4b6db3
EB
991#else
992
993static struct {
994 void (**handlers)(void);
995 size_t nr;
996 size_t alloc;
997} git_atexit_hdlrs;
998
999static int git_atexit_installed;
1000
6066a7ea 1001static void git_atexit_dispatch(void)
0f4b6db3
EB
1002{
1003 size_t i;
1004
1005 for (i=git_atexit_hdlrs.nr ; i ; i--)
1006 git_atexit_hdlrs.handlers[i-1]();
1007}
1008
6066a7ea 1009static void git_atexit_clear(void)
0f4b6db3
EB
1010{
1011 free(git_atexit_hdlrs.handlers);
1012 memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
1013 git_atexit_installed = 0;
1014}
1015
1016#undef atexit
1017int git_atexit(void (*handler)(void))
1018{
1019 ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
1020 git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
1021 if (!git_atexit_installed) {
1022 if (atexit(&git_atexit_dispatch))
1023 return -1;
1024 git_atexit_installed = 1;
1025 }
1026 return 0;
1027}
1028#define atexit git_atexit
1029
661a8cf4
JK
1030static int process_is_async;
1031int in_async(void)
1032{
1033 return process_is_async;
1034}
1035
b992fe10 1036static void NORETURN async_exit(int code)
9658846c
JK
1037{
1038 exit(code);
1039}
1040
618ebe9f
JS
1041#endif
1042
b992fe10
LS
1043void check_pipe(int err)
1044{
1045 if (err == EPIPE) {
1046 if (in_async())
1047 async_exit(141);
1048
1049 signal(SIGPIPE, SIG_DFL);
1050 raise(SIGPIPE);
1051 /* Should never happen, but just in case... */
1052 exit(141);
1053 }
1054}
1055
2d22c208
JS
1056int start_async(struct async *async)
1057{
ae6a5609
EFL
1058 int need_in, need_out;
1059 int fdin[2], fdout[2];
1060 int proc_in, proc_out;
2d22c208 1061
ae6a5609
EFL
1062 need_in = async->in < 0;
1063 if (need_in) {
1064 if (pipe(fdin) < 0) {
1065 if (async->out > 0)
1066 close(async->out);
fbcb0e06 1067 return error_errno("cannot create pipe");
ae6a5609
EFL
1068 }
1069 async->in = fdin[1];
1070 }
1071
1072 need_out = async->out < 0;
1073 if (need_out) {
1074 if (pipe(fdout) < 0) {
1075 if (need_in)
1076 close_pair(fdin);
1077 else if (async->in)
1078 close(async->in);
fbcb0e06 1079 return error_errno("cannot create pipe");
ae6a5609
EFL
1080 }
1081 async->out = fdout[0];
1082 }
1083
1084 if (need_in)
1085 proc_in = fdin[0];
1086 else if (async->in)
1087 proc_in = async->in;
1088 else
1089 proc_in = -1;
1090
1091 if (need_out)
1092 proc_out = fdout[1];
1093 else if (async->out)
1094 proc_out = async->out;
1095 else
1096 proc_out = -1;
2d22c208 1097
f6b60983 1098#ifdef NO_PTHREADS
2c3766f0
AM
1099 /* Flush stdio before fork() to avoid cloning buffers */
1100 fflush(NULL);
1101
2d22c208
JS
1102 async->pid = fork();
1103 if (async->pid < 0) {
fbcb0e06 1104 error_errno("fork (async) failed");
ae6a5609 1105 goto error;
2d22c208
JS
1106 }
1107 if (!async->pid) {
ae6a5609
EFL
1108 if (need_in)
1109 close(fdin[1]);
1110 if (need_out)
1111 close(fdout[0]);
0f4b6db3 1112 git_atexit_clear();
661a8cf4 1113 process_is_async = 1;
ae6a5609 1114 exit(!!async->proc(proc_in, proc_out, async->data));
2d22c208 1115 }
ae6a5609 1116
ac2fbaa6 1117 mark_child_for_cleanup(async->pid, NULL);
afe19ff7 1118
ae6a5609
EFL
1119 if (need_in)
1120 close(fdin[0]);
1121 else if (async->in)
1122 close(async->in);
1123
1124 if (need_out)
1125 close(fdout[1]);
1126 else if (async->out)
1127 close(async->out);
618ebe9f 1128#else
0ea1c89b
JS
1129 if (!main_thread_set) {
1130 /*
1131 * We assume that the first time that start_async is called
1132 * it is from the main thread.
1133 */
1134 main_thread_set = 1;
1135 main_thread = pthread_self();
1136 pthread_key_create(&async_key, NULL);
1ece66bc 1137 pthread_key_create(&async_die_counter, NULL);
0ea1c89b 1138 set_die_routine(die_async);
1ece66bc 1139 set_die_is_recursing_routine(async_die_is_recursing);
0ea1c89b
JS
1140 }
1141
200a76b7
JS
1142 if (proc_in >= 0)
1143 set_cloexec(proc_in);
1144 if (proc_out >= 0)
1145 set_cloexec(proc_out);
ae6a5609
EFL
1146 async->proc_in = proc_in;
1147 async->proc_out = proc_out;
200a76b7
JS
1148 {
1149 int err = pthread_create(&async->tid, NULL, run_thread, async);
1150 if (err) {
fbcb0e06 1151 error_errno("cannot create thread");
200a76b7
JS
1152 goto error;
1153 }
618ebe9f
JS
1154 }
1155#endif
2d22c208 1156 return 0;
ae6a5609
EFL
1157
1158error:
1159 if (need_in)
1160 close_pair(fdin);
1161 else if (async->in)
1162 close(async->in);
1163
1164 if (need_out)
1165 close_pair(fdout);
1166 else if (async->out)
1167 close(async->out);
1168 return -1;
2d22c208
JS
1169}
1170
1171int finish_async(struct async *async)
1172{
f6b60983 1173#ifdef NO_PTHREADS
507d7804 1174 return wait_or_whine(async->pid, "child process", 0);
618ebe9f 1175#else
200a76b7
JS
1176 void *ret = (void *)(intptr_t)(-1);
1177
1178 if (pthread_join(async->tid, &ret))
1179 error("pthread_join failed");
1180 return (int)(intptr_t)ret;
618ebe9f 1181#endif
2d22c208 1182}
ae98a008 1183
dcf69262 1184const char *find_hook(const char *name)
5a7da2dc 1185{
03f2c773 1186 static struct strbuf path = STRBUF_INIT;
5a7da2dc 1187
03f2c773 1188 strbuf_reset(&path);
9445b492 1189 strbuf_git_path(&path, "hooks/%s", name);
235be51f 1190 if (access(path.buf, X_OK) < 0) {
f805a00a
DM
1191 int err = errno;
1192
235be51f
JS
1193#ifdef STRIP_EXTENSION
1194 strbuf_addstr(&path, STRIP_EXTENSION);
1195 if (access(path.buf, X_OK) >= 0)
1196 return path.buf;
f805a00a
DM
1197 if (errno == EACCES)
1198 err = errno;
235be51f 1199#endif
f805a00a
DM
1200
1201 if (err == EACCES && advice_ignored_hook) {
1202 static struct string_list advise_given = STRING_LIST_INIT_DUP;
1203
1204 if (!string_list_lookup(&advise_given, name)) {
1205 string_list_insert(&advise_given, name);
1206 advise(_("The '%s' hook was ignored because "
1207 "it's not set as executable.\n"
1208 "You can disable this warning with "
1209 "`git config advice.ignoredHook false`."),
1210 path.buf);
1211 }
1212 }
03f2c773 1213 return NULL;
235be51f 1214 }
03f2c773 1215 return path.buf;
5a7da2dc
AS
1216}
1217
15048f8a 1218int run_hook_ve(const char *const *env, const char *name, va_list args)
ae98a008 1219{
d3180279 1220 struct child_process hook = CHILD_PROCESS_INIT;
15048f8a 1221 const char *p;
ae98a008 1222
5a7da2dc
AS
1223 p = find_hook(name);
1224 if (!p)
cf94ca8e
SB
1225 return 0;
1226
d1d09456
RS
1227 argv_array_push(&hook.args, p);
1228 while ((p = va_arg(args, const char *)))
1229 argv_array_push(&hook.args, p);
15048f8a 1230 hook.env = env;
ae98a008
SB
1231 hook.no_stdin = 1;
1232 hook.stdout_to_stderr = 1;
ae98a008 1233
d1d09456 1234 return run_command(&hook);
ae98a008 1235}
15048f8a
BP
1236
1237int run_hook_le(const char *const *env, const char *name, ...)
1238{
1239 va_list args;
1240 int ret;
1241
1242 va_start(args, name);
1243 ret = run_hook_ve(env, name, args);
1244 va_end(args);
1245
1246 return ret;
1247}
911ec99b 1248
96335bcf
JK
1249struct io_pump {
1250 /* initialized by caller */
1251 int fd;
1252 int type; /* POLLOUT or POLLIN */
1253 union {
1254 struct {
1255 const char *buf;
1256 size_t len;
1257 } out;
1258 struct {
1259 struct strbuf *buf;
1260 size_t hint;
1261 } in;
1262 } u;
1263
1264 /* returned by pump_io */
1265 int error; /* 0 for success, otherwise errno */
1266
1267 /* internal use */
1268 struct pollfd *pfd;
1269};
1270
1271static int pump_io_round(struct io_pump *slots, int nr, struct pollfd *pfd)
1272{
1273 int pollsize = 0;
1274 int i;
1275
1276 for (i = 0; i < nr; i++) {
1277 struct io_pump *io = &slots[i];
1278 if (io->fd < 0)
1279 continue;
1280 pfd[pollsize].fd = io->fd;
1281 pfd[pollsize].events = io->type;
1282 io->pfd = &pfd[pollsize++];
1283 }
1284
1285 if (!pollsize)
1286 return 0;
1287
1288 if (poll(pfd, pollsize, -1) < 0) {
1289 if (errno == EINTR)
1290 return 1;
1291 die_errno("poll failed");
1292 }
1293
1294 for (i = 0; i < nr; i++) {
1295 struct io_pump *io = &slots[i];
1296
1297 if (io->fd < 0)
1298 continue;
1299
1300 if (!(io->pfd->revents & (POLLOUT|POLLIN|POLLHUP|POLLERR|POLLNVAL)))
1301 continue;
1302
1303 if (io->type == POLLOUT) {
1304 ssize_t len = xwrite(io->fd,
1305 io->u.out.buf, io->u.out.len);
1306 if (len < 0) {
1307 io->error = errno;
1308 close(io->fd);
1309 io->fd = -1;
1310 } else {
1311 io->u.out.buf += len;
1312 io->u.out.len -= len;
1313 if (!io->u.out.len) {
1314 close(io->fd);
1315 io->fd = -1;
1316 }
1317 }
1318 }
1319
1320 if (io->type == POLLIN) {
1321 ssize_t len = strbuf_read_once(io->u.in.buf,
1322 io->fd, io->u.in.hint);
1323 if (len < 0)
1324 io->error = errno;
1325 if (len <= 0) {
1326 close(io->fd);
1327 io->fd = -1;
1328 }
1329 }
1330 }
1331
1332 return 1;
1333}
1334
1335static int pump_io(struct io_pump *slots, int nr)
911ec99b 1336{
96335bcf
JK
1337 struct pollfd *pfd;
1338 int i;
1339
1340 for (i = 0; i < nr; i++)
1341 slots[i].error = 0;
1342
1343 ALLOC_ARRAY(pfd, nr);
1344 while (pump_io_round(slots, nr, pfd))
1345 ; /* nothing */
1346 free(pfd);
1347
1348 /* There may be multiple errno values, so just pick the first. */
1349 for (i = 0; i < nr; i++) {
1350 if (slots[i].error) {
1351 errno = slots[i].error;
1352 return -1;
1353 }
1354 }
1355 return 0;
1356}
1357
1358
1359int pipe_command(struct child_process *cmd,
1360 const char *in, size_t in_len,
1361 struct strbuf *out, size_t out_hint,
1362 struct strbuf *err, size_t err_hint)
1363{
1364 struct io_pump io[3];
1365 int nr = 0;
1366
1367 if (in)
1368 cmd->in = -1;
1369 if (out)
1370 cmd->out = -1;
1371 if (err)
1372 cmd->err = -1;
1373
911ec99b
JK
1374 if (start_command(cmd) < 0)
1375 return -1;
1376
96335bcf
JK
1377 if (in) {
1378 io[nr].fd = cmd->in;
1379 io[nr].type = POLLOUT;
1380 io[nr].u.out.buf = in;
1381 io[nr].u.out.len = in_len;
1382 nr++;
1383 }
1384 if (out) {
1385 io[nr].fd = cmd->out;
1386 io[nr].type = POLLIN;
1387 io[nr].u.in.buf = out;
1388 io[nr].u.in.hint = out_hint;
1389 nr++;
1390 }
1391 if (err) {
1392 io[nr].fd = cmd->err;
1393 io[nr].type = POLLIN;
1394 io[nr].u.in.buf = err;
1395 io[nr].u.in.hint = err_hint;
1396 nr++;
1397 }
1398
1399 if (pump_io(io, nr) < 0) {
911ec99b
JK
1400 finish_command(cmd); /* throw away exit code */
1401 return -1;
1402 }
1403
911ec99b
JK
1404 return finish_command(cmd);
1405}
c553c72e
SB
1406
1407enum child_state {
1408 GIT_CP_FREE,
1409 GIT_CP_WORKING,
1410 GIT_CP_WAIT_CLEANUP,
1411};
1412
1413struct parallel_processes {
1414 void *data;
1415
1416 int max_processes;
1417 int nr_processes;
1418
1419 get_next_task_fn get_next_task;
1420 start_failure_fn start_failure;
1421 task_finished_fn task_finished;
1422
1423 struct {
1424 enum child_state state;
1425 struct child_process process;
1426 struct strbuf err;
1427 void *data;
1428 } *children;
1429 /*
1430 * The struct pollfd is logically part of *children,
1431 * but the system call expects it as its own array.
1432 */
1433 struct pollfd *pfd;
1434
1435 unsigned shutdown : 1;
1436
1437 int output_owner;
1438 struct strbuf buffered_output; /* of finished children */
1439};
1440
aa710494 1441static int default_start_failure(struct strbuf *out,
c553c72e
SB
1442 void *pp_cb,
1443 void *pp_task_cb)
1444{
c553c72e
SB
1445 return 0;
1446}
1447
1448static int default_task_finished(int result,
aa710494 1449 struct strbuf *out,
c553c72e
SB
1450 void *pp_cb,
1451 void *pp_task_cb)
1452{
c553c72e
SB
1453 return 0;
1454}
1455
1456static void kill_children(struct parallel_processes *pp, int signo)
1457{
1458 int i, n = pp->max_processes;
1459
1460 for (i = 0; i < n; i++)
1461 if (pp->children[i].state == GIT_CP_WORKING)
1462 kill(pp->children[i].process.pid, signo);
1463}
1464
1465static struct parallel_processes *pp_for_signal;
1466
1467static void handle_children_on_signal(int signo)
1468{
1469 kill_children(pp_for_signal, signo);
1470 sigchain_pop(signo);
1471 raise(signo);
1472}
1473
1474static void pp_init(struct parallel_processes *pp,
1475 int n,
1476 get_next_task_fn get_next_task,
1477 start_failure_fn start_failure,
1478 task_finished_fn task_finished,
1479 void *data)
1480{
1481 int i;
1482
1483 if (n < 1)
1484 n = online_cpus();
1485
1486 pp->max_processes = n;
1487
1488 trace_printf("run_processes_parallel: preparing to run up to %d tasks", n);
1489
1490 pp->data = data;
1491 if (!get_next_task)
1492 die("BUG: you need to specify a get_next_task function");
1493 pp->get_next_task = get_next_task;
1494
1495 pp->start_failure = start_failure ? start_failure : default_start_failure;
1496 pp->task_finished = task_finished ? task_finished : default_task_finished;
1497
1498 pp->nr_processes = 0;
1499 pp->output_owner = 0;
1500 pp->shutdown = 0;
1501 pp->children = xcalloc(n, sizeof(*pp->children));
1502 pp->pfd = xcalloc(n, sizeof(*pp->pfd));
1503 strbuf_init(&pp->buffered_output, 0);
1504
1505 for (i = 0; i < n; i++) {
1506 strbuf_init(&pp->children[i].err, 0);
1507 child_process_init(&pp->children[i].process);
1508 pp->pfd[i].events = POLLIN | POLLHUP;
1509 pp->pfd[i].fd = -1;
1510 }
1511
1512 pp_for_signal = pp;
1513 sigchain_push_common(handle_children_on_signal);
1514}
1515
1516static void pp_cleanup(struct parallel_processes *pp)
1517{
1518 int i;
1519
1520 trace_printf("run_processes_parallel: done");
1521 for (i = 0; i < pp->max_processes; i++) {
1522 strbuf_release(&pp->children[i].err);
1523 child_process_clear(&pp->children[i].process);
1524 }
1525
1526 free(pp->children);
1527 free(pp->pfd);
1528
1529 /*
1530 * When get_next_task added messages to the buffer in its last
1531 * iteration, the buffered output is non empty.
1532 */
2dac9b56 1533 strbuf_write(&pp->buffered_output, stderr);
c553c72e
SB
1534 strbuf_release(&pp->buffered_output);
1535
1536 sigchain_pop_common();
1537}
1538
1539/* returns
1540 * 0 if a new task was started.
1541 * 1 if no new jobs was started (get_next_task ran out of work, non critical
1542 * problem with starting a new command)
1543 * <0 no new job was started, user wishes to shutdown early. Use negative code
1544 * to signal the children.
1545 */
1546static int pp_start_one(struct parallel_processes *pp)
1547{
1548 int i, code;
1549
1550 for (i = 0; i < pp->max_processes; i++)
1551 if (pp->children[i].state == GIT_CP_FREE)
1552 break;
1553 if (i == pp->max_processes)
1554 die("BUG: bookkeeping is hard");
1555
1556 code = pp->get_next_task(&pp->children[i].process,
1557 &pp->children[i].err,
1558 pp->data,
1559 &pp->children[i].data);
1560 if (!code) {
1561 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1562 strbuf_reset(&pp->children[i].err);
1563 return 1;
1564 }
1565 pp->children[i].process.err = -1;
1566 pp->children[i].process.stdout_to_stderr = 1;
1567 pp->children[i].process.no_stdin = 1;
1568
1569 if (start_command(&pp->children[i].process)) {
2a73b3da 1570 code = pp->start_failure(&pp->children[i].err,
c553c72e 1571 pp->data,
c1e860f1 1572 pp->children[i].data);
c553c72e
SB
1573 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1574 strbuf_reset(&pp->children[i].err);
1575 if (code)
1576 pp->shutdown = 1;
1577 return code;
1578 }
1579
1580 pp->nr_processes++;
1581 pp->children[i].state = GIT_CP_WORKING;
1582 pp->pfd[i].fd = pp->children[i].process.err;
1583 return 0;
1584}
1585
1586static void pp_buffer_stderr(struct parallel_processes *pp, int output_timeout)
1587{
1588 int i;
1589
1590 while ((i = poll(pp->pfd, pp->max_processes, output_timeout)) < 0) {
1591 if (errno == EINTR)
1592 continue;
1593 pp_cleanup(pp);
1594 die_errno("poll");
1595 }
1596
1597 /* Buffer output from all pipes. */
1598 for (i = 0; i < pp->max_processes; i++) {
1599 if (pp->children[i].state == GIT_CP_WORKING &&
1600 pp->pfd[i].revents & (POLLIN | POLLHUP)) {
1601 int n = strbuf_read_once(&pp->children[i].err,
1602 pp->children[i].process.err, 0);
1603 if (n == 0) {
1604 close(pp->children[i].process.err);
1605 pp->children[i].state = GIT_CP_WAIT_CLEANUP;
1606 } else if (n < 0)
1607 if (errno != EAGAIN)
1608 die_errno("read");
1609 }
1610 }
1611}
1612
1613static void pp_output(struct parallel_processes *pp)
1614{
1615 int i = pp->output_owner;
1616 if (pp->children[i].state == GIT_CP_WORKING &&
1617 pp->children[i].err.len) {
2dac9b56 1618 strbuf_write(&pp->children[i].err, stderr);
c553c72e
SB
1619 strbuf_reset(&pp->children[i].err);
1620 }
1621}
1622
1623static int pp_collect_finished(struct parallel_processes *pp)
1624{
1625 int i, code;
1626 int n = pp->max_processes;
1627 int result = 0;
1628
1629 while (pp->nr_processes > 0) {
1630 for (i = 0; i < pp->max_processes; i++)
1631 if (pp->children[i].state == GIT_CP_WAIT_CLEANUP)
1632 break;
1633 if (i == pp->max_processes)
1634 break;
1635
1636 code = finish_command(&pp->children[i].process);
1637
2a73b3da 1638 code = pp->task_finished(code,
c553c72e 1639 &pp->children[i].err, pp->data,
c1e860f1 1640 pp->children[i].data);
c553c72e
SB
1641
1642 if (code)
1643 result = code;
1644 if (code < 0)
1645 break;
1646
1647 pp->nr_processes--;
1648 pp->children[i].state = GIT_CP_FREE;
1649 pp->pfd[i].fd = -1;
1650 child_process_init(&pp->children[i].process);
1651
1652 if (i != pp->output_owner) {
1653 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1654 strbuf_reset(&pp->children[i].err);
1655 } else {
2dac9b56 1656 strbuf_write(&pp->children[i].err, stderr);
c553c72e
SB
1657 strbuf_reset(&pp->children[i].err);
1658
1659 /* Output all other finished child processes */
2dac9b56 1660 strbuf_write(&pp->buffered_output, stderr);
c553c72e
SB
1661 strbuf_reset(&pp->buffered_output);
1662
1663 /*
1664 * Pick next process to output live.
1665 * NEEDSWORK:
1666 * For now we pick it randomly by doing a round
1667 * robin. Later we may want to pick the one with
1668 * the most output or the longest or shortest
1669 * running process time.
1670 */
1671 for (i = 0; i < n; i++)
1672 if (pp->children[(pp->output_owner + i) % n].state == GIT_CP_WORKING)
1673 break;
1674 pp->output_owner = (pp->output_owner + i) % n;
1675 }
1676 }
1677 return result;
1678}
1679
1680int run_processes_parallel(int n,
1681 get_next_task_fn get_next_task,
1682 start_failure_fn start_failure,
1683 task_finished_fn task_finished,
1684 void *pp_cb)
1685{
1686 int i, code;
1687 int output_timeout = 100;
1688 int spawn_cap = 4;
1689 struct parallel_processes pp;
1690
1691 pp_init(&pp, n, get_next_task, start_failure, task_finished, pp_cb);
1692 while (1) {
1693 for (i = 0;
1694 i < spawn_cap && !pp.shutdown &&
1695 pp.nr_processes < pp.max_processes;
1696 i++) {
1697 code = pp_start_one(&pp);
1698 if (!code)
1699 continue;
1700 if (code < 0) {
1701 pp.shutdown = 1;
1702 kill_children(&pp, -code);
1703 }
1704 break;
1705 }
1706 if (!pp.nr_processes)
1707 break;
1708 pp_buffer_stderr(&pp, output_timeout);
1709 pp_output(&pp);
1710 code = pp_collect_finished(&pp);
1711 if (code) {
1712 pp.shutdown = 1;
1713 if (code < 0)
1714 kill_children(&pp, -code);
1715 }
1716 }
1717
1718 pp_cleanup(&pp);
1719 return 0;
1720}