run-command.c: print env vars in trace_run_command()
[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
c61a975d
NTND
560static void trace_add_env(struct strbuf *dst, const char *const *deltaenv)
561{
562 struct string_list envs = STRING_LIST_INIT_DUP;
563 const char *const *e;
564 int i;
565 int printed_unset = 0;
566
567 /* Last one wins, see run-command.c:prep_childenv() for context */
568 for (e = deltaenv; e && *e; e++) {
569 struct strbuf key = STRBUF_INIT;
570 char *equals = strchr(*e, '=');
571
572 if (equals) {
573 strbuf_add(&key, *e, equals - *e);
574 string_list_insert(&envs, key.buf)->util = equals + 1;
575 } else {
576 string_list_insert(&envs, *e)->util = NULL;
577 }
578 strbuf_release(&key);
579 }
580
581 /* "unset X Y...;" */
582 for (i = 0; i < envs.nr; i++) {
583 const char *var = envs.items[i].string;
584 const char *val = envs.items[i].util;
585
586 if (val || !getenv(var))
587 continue;
588
589 if (!printed_unset) {
590 strbuf_addstr(dst, " unset");
591 printed_unset = 1;
592 }
593 strbuf_addf(dst, " %s", var);
594 }
595 if (printed_unset)
596 strbuf_addch(dst, ';');
597
598 /* ... followed by "A=B C=D ..." */
599 for (i = 0; i < envs.nr; i++) {
600 const char *var = envs.items[i].string;
601 const char *val = envs.items[i].util;
602 const char *oldval;
603
604 if (!val)
605 continue;
606
607 oldval = getenv(var);
608 if (oldval && !strcmp(val, oldval))
609 continue;
610
611 strbuf_addf(dst, " %s=", var);
612 sq_quote_buf_pretty(dst, val);
613 }
614 string_list_clear(&envs, 0);
615}
616
e73dd786
NTND
617static void trace_run_command(const struct child_process *cp)
618{
619 struct strbuf buf = STRBUF_INIT;
620
621 if (!trace_want(&trace_default_key))
622 return;
623
624 strbuf_addf(&buf, "trace: run_command:");
c61a975d
NTND
625 /*
626 * The caller is responsible for initializing cp->env from
627 * cp->env_array if needed. We only check one place.
628 */
629 if (cp->env)
630 trace_add_env(&buf, cp->env);
21dfc5e0
NTND
631 if (cp->git_cmd)
632 strbuf_addstr(&buf, " git");
e73dd786
NTND
633 sq_quote_argv_pretty(&buf, cp->argv);
634
635 trace_printf("%s", buf.buf);
636 strbuf_release(&buf);
637}
638
ebcb5d16 639int start_command(struct child_process *cmd)
b1bf95bb 640{
f3b33f1d
JS
641 int need_in, need_out, need_err;
642 int fdin[2], fdout[2], fderr[2];
25043d8a 643 int failed_errno;
939296c4 644 char *str;
4919bf03 645
c460c0ec
JK
646 if (!cmd->argv)
647 cmd->argv = cmd->args.argv;
19a583dc
RS
648 if (!cmd->env)
649 cmd->env = cmd->env_array.argv;
c460c0ec 650
c20181e3
JS
651 /*
652 * In case of errors we must keep the promise to close FDs
653 * that have been passed in via ->in and ->out.
654 */
655
e4507ae8 656 need_in = !cmd->no_stdin && cmd->in < 0;
4919bf03 657 if (need_in) {
c20181e3 658 if (pipe(fdin) < 0) {
0ac77ec3 659 failed_errno = errno;
c20181e3
JS
660 if (cmd->out > 0)
661 close(cmd->out);
939296c4 662 str = "standard input";
0ac77ec3 663 goto fail_pipe;
c20181e3 664 }
4919bf03 665 cmd->in = fdin[1];
4919bf03
SP
666 }
667
e4507ae8
SP
668 need_out = !cmd->no_stdout
669 && !cmd->stdout_to_stderr
670 && cmd->out < 0;
f4bba25b
SP
671 if (need_out) {
672 if (pipe(fdout) < 0) {
0ac77ec3 673 failed_errno = errno;
f4bba25b
SP
674 if (need_in)
675 close_pair(fdin);
c20181e3
JS
676 else if (cmd->in)
677 close(cmd->in);
939296c4 678 str = "standard output";
0ac77ec3 679 goto fail_pipe;
f4bba25b
SP
680 }
681 cmd->out = fdout[0];
f4bba25b
SP
682 }
683
b73a4397 684 need_err = !cmd->no_stderr && cmd->err < 0;
f3b33f1d
JS
685 if (need_err) {
686 if (pipe(fderr) < 0) {
0ac77ec3 687 failed_errno = errno;
f3b33f1d
JS
688 if (need_in)
689 close_pair(fdin);
c20181e3
JS
690 else if (cmd->in)
691 close(cmd->in);
f3b33f1d
JS
692 if (need_out)
693 close_pair(fdout);
c20181e3
JS
694 else if (cmd->out)
695 close(cmd->out);
939296c4 696 str = "standard error";
0ac77ec3 697fail_pipe:
939296c4
SB
698 error("cannot create %s pipe for %s: %s",
699 str, cmd->argv[0], strerror(failed_errno));
2d71608e 700 child_process_clear(cmd);
0ac77ec3
JS
701 errno = failed_errno;
702 return -1;
f3b33f1d
JS
703 }
704 cmd->err = fderr[0];
705 }
706
e73dd786
NTND
707 trace_run_command(cmd);
708
13af8cbd 709 fflush(NULL);
8852f5d7 710
380395d0 711#ifndef GIT_WINDOWS_NATIVE
2b541bf8
JS
712{
713 int notify_pipe[2];
db015a28 714 int null_fd = -1;
ae25394b 715 char **childenv;
3967e25b 716 struct argv_array argv = ARGV_ARRAY_INIT;
79319b19 717 struct child_err cerr;
45afb1ca 718 struct atfork_state as;
3967e25b 719
2b541bf8
JS
720 if (pipe(notify_pipe))
721 notify_pipe[0] = notify_pipe[1] = -1;
722
db015a28
BW
723 if (cmd->no_stdin || cmd->no_stdout || cmd->no_stderr) {
724 null_fd = open("/dev/null", O_RDWR | O_CLOEXEC);
725 if (null_fd < 0)
726 die_errno(_("open /dev/null failed"));
727 set_cloexec(null_fd);
728 }
729
3967e25b 730 prepare_cmd(&argv, cmd);
ae25394b 731 childenv = prep_childenv(cmd->env);
45afb1ca 732 atfork_prepare(&as);
3967e25b 733
e503cd6e
BW
734 /*
735 * NOTE: In order to prevent deadlocking when using threads special
736 * care should be taken with the function calls made in between the
737 * fork() and exec() calls. No calls should be made to functions which
738 * require acquiring a lock (e.g. malloc) as the lock could have been
739 * held by another thread at the time of forking, causing the lock to
740 * never be released in the child process. This means only
741 * Async-Signal-Safe functions are permitted in the child.
742 */
ebcb5d16 743 cmd->pid = fork();
25043d8a 744 failed_errno = errno;
ebcb5d16 745 if (!cmd->pid) {
45afb1ca 746 int sig;
a5487ddf 747 /*
79319b19
BW
748 * Ensure the default die/error/warn routines do not get
749 * called, they can take stdio locks and malloc.
a5487ddf 750 */
79319b19
BW
751 set_die_routine(child_die_fn);
752 set_error_routine(child_error_fn);
753 set_warn_routine(child_warn_fn);
a5487ddf 754
2b541bf8
JS
755 close(notify_pipe[0]);
756 set_cloexec(notify_pipe[1]);
757 child_notifier = notify_pipe[1];
2b541bf8 758
e4507ae8 759 if (cmd->no_stdin)
53fa6753 760 child_dup2(null_fd, 0);
e4507ae8 761 else if (need_in) {
53fa6753
BW
762 child_dup2(fdin[0], 0);
763 child_close_pair(fdin);
4919bf03 764 } else if (cmd->in) {
53fa6753
BW
765 child_dup2(cmd->in, 0);
766 child_close(cmd->in);
95d3c4f5 767 }
4919bf03 768
ce2cf27a 769 if (cmd->no_stderr)
53fa6753 770 child_dup2(null_fd, 2);
ce2cf27a 771 else if (need_err) {
53fa6753
BW
772 child_dup2(fderr[1], 2);
773 child_close_pair(fderr);
4f41b611 774 } else if (cmd->err > 1) {
53fa6753
BW
775 child_dup2(cmd->err, 2);
776 child_close(cmd->err);
ce2cf27a
CC
777 }
778
e4507ae8 779 if (cmd->no_stdout)
53fa6753 780 child_dup2(null_fd, 1);
e4507ae8 781 else if (cmd->stdout_to_stderr)
53fa6753 782 child_dup2(2, 1);
f4bba25b 783 else if (need_out) {
53fa6753
BW
784 child_dup2(fdout[1], 1);
785 child_close_pair(fdout);
f4bba25b 786 } else if (cmd->out > 1) {
53fa6753
BW
787 child_dup2(cmd->out, 1);
788 child_close(cmd->out);
f4bba25b
SP
789 }
790
1568fea0 791 if (cmd->dir && chdir(cmd->dir))
79319b19 792 child_die(CHILD_ERR_CHDIR);
3967e25b 793
45afb1ca
EW
794 /*
795 * restore default signal handlers here, in case
796 * we catch a signal right before execve below
797 */
798 for (sig = 1; sig < NSIG; sig++) {
799 /* ignored signals get reset to SIG_DFL on execve */
800 if (signal(sig, SIG_DFL) == SIG_IGN)
801 signal(sig, SIG_IGN);
802 }
803
804 if (sigprocmask(SIG_SETMASK, &as.old, NULL) != 0)
805 child_die(CHILD_ERR_SIGPROCMASK);
806
e3a43446
BW
807 /*
808 * Attempt to exec using the command and arguments starting at
809 * argv.argv[1]. argv.argv[0] contains SHELL_PATH which will
810 * be used in the event exec failed with ENOEXEC at which point
811 * we will try to interpret the command using 'sh'.
812 */
ae25394b
BW
813 execve(argv.argv[1], (char *const *) argv.argv + 1,
814 (char *const *) childenv);
e3a43446 815 if (errno == ENOEXEC)
ae25394b
BW
816 execve(argv.argv[0], (char *const *) argv.argv,
817 (char *const *) childenv);
3967e25b 818
fc1b56f0 819 if (errno == ENOENT) {
79319b19
BW
820 if (cmd->silent_exec_failure)
821 child_die(CHILD_ERR_SILENT);
822 child_die(CHILD_ERR_ENOENT);
fc1b56f0 823 } else {
79319b19 824 child_die(CHILD_ERR_ERRNO);
fc1b56f0 825 }
b1bf95bb 826 }
45afb1ca 827 atfork_parent(&as);
0ac77ec3 828 if (cmd->pid < 0)
fbcb0e06 829 error_errno("cannot fork() for %s", cmd->argv[0]);
afe19ff7 830 else if (cmd->clean_on_exit)
ac2fbaa6 831 mark_child_for_cleanup(cmd->pid, cmd);
2b541bf8
JS
832
833 /*
3967e25b 834 * Wait for child's exec. If the exec succeeds (or if fork()
2b541bf8 835 * failed), EOF is seen immediately by the parent. Otherwise, the
79319b19 836 * child process sends a child_err struct.
2b541bf8
JS
837 * Note that use of this infrastructure is completely advisory,
838 * therefore, we keep error checks minimal.
839 */
840 close(notify_pipe[1]);
79319b19 841 if (xread(notify_pipe[0], &cerr, sizeof(cerr)) == sizeof(cerr)) {
2b541bf8 842 /*
3967e25b 843 * At this point we know that fork() succeeded, but exec()
2b541bf8
JS
844 * failed. Errors have been reported to our stderr.
845 */
507d7804 846 wait_or_whine(cmd->pid, cmd->argv[0], 0);
79319b19 847 child_err_spew(cmd, &cerr);
2b541bf8
JS
848 failed_errno = errno;
849 cmd->pid = -1;
850 }
851 close(notify_pipe[0]);
3967e25b 852
db015a28
BW
853 if (null_fd >= 0)
854 close(null_fd);
3967e25b 855 argv_array_clear(&argv);
ae25394b 856 free(childenv);
2b541bf8 857}
ba26f296 858#else
0d30ad71 859{
75301f90 860 int fhin = 0, fhout = 1, fherr = 2;
108ac313 861 const char **sargv = cmd->argv;
20574f55 862 struct argv_array nargv = ARGV_ARRAY_INIT;
ba26f296 863
75301f90
JS
864 if (cmd->no_stdin)
865 fhin = open("/dev/null", O_RDWR);
866 else if (need_in)
867 fhin = dup(fdin[0]);
868 else if (cmd->in)
869 fhin = dup(cmd->in);
870
871 if (cmd->no_stderr)
872 fherr = open("/dev/null", O_RDWR);
873 else if (need_err)
874 fherr = dup(fderr[1]);
76d44c8c
JH
875 else if (cmd->err > 2)
876 fherr = dup(cmd->err);
75301f90
JS
877
878 if (cmd->no_stdout)
879 fhout = open("/dev/null", O_RDWR);
880 else if (cmd->stdout_to_stderr)
881 fhout = dup(fherr);
882 else if (need_out)
883 fhout = dup(fdout[1]);
884 else if (cmd->out > 1)
885 fhout = dup(cmd->out);
ba26f296 886
5a50085c 887 if (cmd->git_cmd)
20574f55 888 cmd->argv = prepare_git_cmd(&nargv, cmd->argv);
5a50085c 889 else if (cmd->use_shell)
20574f55 890 cmd->argv = prepare_shell_cmd(&nargv, cmd->argv);
ba26f296 891
77734da2
KB
892 cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
893 cmd->dir, fhin, fhout, fherr);
0ac77ec3 894 failed_errno = errno;
c024beb5 895 if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
fbcb0e06 896 error_errno("cannot spawn %s", cmd->argv[0]);
afe19ff7 897 if (cmd->clean_on_exit && cmd->pid >= 0)
ac2fbaa6 898 mark_child_for_cleanup(cmd->pid, cmd);
ba26f296 899
20574f55 900 argv_array_clear(&nargv);
108ac313 901 cmd->argv = sargv;
75301f90
JS
902 if (fhin != 0)
903 close(fhin);
904 if (fhout != 1)
905 close(fhout);
906 if (fherr != 2)
907 close(fherr);
0d30ad71 908}
ba26f296
JS
909#endif
910
911 if (cmd->pid < 0) {
912 if (need_in)
913 close_pair(fdin);
914 else if (cmd->in)
915 close(cmd->in);
916 if (need_out)
917 close_pair(fdout);
918 else if (cmd->out)
919 close(cmd->out);
920 if (need_err)
921 close_pair(fderr);
fc012c28
D
922 else if (cmd->err)
923 close(cmd->err);
2d71608e 924 child_process_clear(cmd);
0ac77ec3
JS
925 errno = failed_errno;
926 return -1;
ba26f296 927 }
4919bf03
SP
928
929 if (need_in)
930 close(fdin[0]);
931 else if (cmd->in)
932 close(cmd->in);
933
f4bba25b
SP
934 if (need_out)
935 close(fdout[1]);
c20181e3 936 else if (cmd->out)
f4bba25b
SP
937 close(cmd->out);
938
f3b33f1d
JS
939 if (need_err)
940 close(fderr[1]);
4f41b611
SP
941 else if (cmd->err)
942 close(cmd->err);
f3b33f1d 943
ebcb5d16
SP
944 return 0;
945}
946
2d22c208
JS
947int finish_command(struct child_process *cmd)
948{
507d7804 949 int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
2d71608e 950 child_process_clear(cmd);
c460c0ec 951 return ret;
2d22c208
JS
952}
953
507d7804
TI
954int finish_command_in_signal(struct child_process *cmd)
955{
956 return wait_or_whine(cmd->pid, cmd->argv[0], 1);
957}
958
959
ebcb5d16
SP
960int run_command(struct child_process *cmd)
961{
c29b3962
JK
962 int code;
963
964 if (cmd->out < 0 || cmd->err < 0)
965 die("BUG: run_command with a pipe can cause deadlock");
966
967 code = start_command(cmd);
ebcb5d16
SP
968 if (code)
969 return code;
970 return finish_command(cmd);
971}
972
f1000898
SP
973int run_command_v_opt(const char **argv, int opt)
974{
41e9bad7 975 return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
1568fea0
AR
976}
977
ee493148
AR
978int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
979{
1f87293d
RS
980 struct child_process cmd = CHILD_PROCESS_INIT;
981 cmd.argv = argv;
982 cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
983 cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
984 cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
985 cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
986 cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
987 cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
ee493148
AR
988 cmd.dir = dir;
989 cmd.env = env;
990 return run_command(&cmd);
991}
2d22c208 992
f6b60983 993#ifndef NO_PTHREADS
0ea1c89b
JS
994static pthread_t main_thread;
995static int main_thread_set;
996static pthread_key_t async_key;
1ece66bc 997static pthread_key_t async_die_counter;
0ea1c89b 998
200a76b7 999static void *run_thread(void *data)
618ebe9f
JS
1000{
1001 struct async *async = data;
f6b60983 1002 intptr_t ret;
0ea1c89b 1003
c792d7b6
JK
1004 if (async->isolate_sigpipe) {
1005 sigset_t mask;
1006 sigemptyset(&mask);
1007 sigaddset(&mask, SIGPIPE);
1008 if (pthread_sigmask(SIG_BLOCK, &mask, NULL) < 0) {
1009 ret = error("unable to block SIGPIPE in async thread");
1010 return (void *)ret;
1011 }
1012 }
1013
0ea1c89b 1014 pthread_setspecific(async_key, async);
f6b60983 1015 ret = async->proc(async->proc_in, async->proc_out, async->data);
200a76b7 1016 return (void *)ret;
618ebe9f 1017}
0ea1c89b
JS
1018
1019static NORETURN void die_async(const char *err, va_list params)
1020{
1021 vreportf("fatal: ", err, params);
1022
661a8cf4 1023 if (in_async()) {
0ea1c89b
JS
1024 struct async *async = pthread_getspecific(async_key);
1025 if (async->proc_in >= 0)
1026 close(async->proc_in);
1027 if (async->proc_out >= 0)
1028 close(async->proc_out);
1029 pthread_exit((void *)128);
1030 }
1031
1032 exit(128);
618ebe9f 1033}
1ece66bc
JK
1034
1035static int async_die_is_recursing(void)
1036{
1037 void *ret = pthread_getspecific(async_die_counter);
1038 pthread_setspecific(async_die_counter, (void *)1);
1039 return ret != NULL;
1040}
1041
661a8cf4
JK
1042int in_async(void)
1043{
1044 if (!main_thread_set)
1045 return 0; /* no asyncs started yet */
1046 return !pthread_equal(main_thread, pthread_self());
1047}
1048
b992fe10 1049static void NORETURN async_exit(int code)
9658846c
JK
1050{
1051 pthread_exit((void *)(intptr_t)code);
1052}
1053
0f4b6db3
EB
1054#else
1055
1056static struct {
1057 void (**handlers)(void);
1058 size_t nr;
1059 size_t alloc;
1060} git_atexit_hdlrs;
1061
1062static int git_atexit_installed;
1063
6066a7ea 1064static void git_atexit_dispatch(void)
0f4b6db3
EB
1065{
1066 size_t i;
1067
1068 for (i=git_atexit_hdlrs.nr ; i ; i--)
1069 git_atexit_hdlrs.handlers[i-1]();
1070}
1071
6066a7ea 1072static void git_atexit_clear(void)
0f4b6db3
EB
1073{
1074 free(git_atexit_hdlrs.handlers);
1075 memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
1076 git_atexit_installed = 0;
1077}
1078
1079#undef atexit
1080int git_atexit(void (*handler)(void))
1081{
1082 ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
1083 git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
1084 if (!git_atexit_installed) {
1085 if (atexit(&git_atexit_dispatch))
1086 return -1;
1087 git_atexit_installed = 1;
1088 }
1089 return 0;
1090}
1091#define atexit git_atexit
1092
661a8cf4
JK
1093static int process_is_async;
1094int in_async(void)
1095{
1096 return process_is_async;
1097}
1098
b992fe10 1099static void NORETURN async_exit(int code)
9658846c
JK
1100{
1101 exit(code);
1102}
1103
618ebe9f
JS
1104#endif
1105
b992fe10
LS
1106void check_pipe(int err)
1107{
1108 if (err == EPIPE) {
1109 if (in_async())
1110 async_exit(141);
1111
1112 signal(SIGPIPE, SIG_DFL);
1113 raise(SIGPIPE);
1114 /* Should never happen, but just in case... */
1115 exit(141);
1116 }
1117}
1118
2d22c208
JS
1119int start_async(struct async *async)
1120{
ae6a5609
EFL
1121 int need_in, need_out;
1122 int fdin[2], fdout[2];
1123 int proc_in, proc_out;
2d22c208 1124
ae6a5609
EFL
1125 need_in = async->in < 0;
1126 if (need_in) {
1127 if (pipe(fdin) < 0) {
1128 if (async->out > 0)
1129 close(async->out);
fbcb0e06 1130 return error_errno("cannot create pipe");
ae6a5609
EFL
1131 }
1132 async->in = fdin[1];
1133 }
1134
1135 need_out = async->out < 0;
1136 if (need_out) {
1137 if (pipe(fdout) < 0) {
1138 if (need_in)
1139 close_pair(fdin);
1140 else if (async->in)
1141 close(async->in);
fbcb0e06 1142 return error_errno("cannot create pipe");
ae6a5609
EFL
1143 }
1144 async->out = fdout[0];
1145 }
1146
1147 if (need_in)
1148 proc_in = fdin[0];
1149 else if (async->in)
1150 proc_in = async->in;
1151 else
1152 proc_in = -1;
1153
1154 if (need_out)
1155 proc_out = fdout[1];
1156 else if (async->out)
1157 proc_out = async->out;
1158 else
1159 proc_out = -1;
2d22c208 1160
f6b60983 1161#ifdef NO_PTHREADS
2c3766f0
AM
1162 /* Flush stdio before fork() to avoid cloning buffers */
1163 fflush(NULL);
1164
2d22c208
JS
1165 async->pid = fork();
1166 if (async->pid < 0) {
fbcb0e06 1167 error_errno("fork (async) failed");
ae6a5609 1168 goto error;
2d22c208
JS
1169 }
1170 if (!async->pid) {
ae6a5609
EFL
1171 if (need_in)
1172 close(fdin[1]);
1173 if (need_out)
1174 close(fdout[0]);
0f4b6db3 1175 git_atexit_clear();
661a8cf4 1176 process_is_async = 1;
ae6a5609 1177 exit(!!async->proc(proc_in, proc_out, async->data));
2d22c208 1178 }
ae6a5609 1179
ac2fbaa6 1180 mark_child_for_cleanup(async->pid, NULL);
afe19ff7 1181
ae6a5609
EFL
1182 if (need_in)
1183 close(fdin[0]);
1184 else if (async->in)
1185 close(async->in);
1186
1187 if (need_out)
1188 close(fdout[1]);
1189 else if (async->out)
1190 close(async->out);
618ebe9f 1191#else
0ea1c89b
JS
1192 if (!main_thread_set) {
1193 /*
1194 * We assume that the first time that start_async is called
1195 * it is from the main thread.
1196 */
1197 main_thread_set = 1;
1198 main_thread = pthread_self();
1199 pthread_key_create(&async_key, NULL);
1ece66bc 1200 pthread_key_create(&async_die_counter, NULL);
0ea1c89b 1201 set_die_routine(die_async);
1ece66bc 1202 set_die_is_recursing_routine(async_die_is_recursing);
0ea1c89b
JS
1203 }
1204
200a76b7
JS
1205 if (proc_in >= 0)
1206 set_cloexec(proc_in);
1207 if (proc_out >= 0)
1208 set_cloexec(proc_out);
ae6a5609
EFL
1209 async->proc_in = proc_in;
1210 async->proc_out = proc_out;
200a76b7
JS
1211 {
1212 int err = pthread_create(&async->tid, NULL, run_thread, async);
1213 if (err) {
fbcb0e06 1214 error_errno("cannot create thread");
200a76b7
JS
1215 goto error;
1216 }
618ebe9f
JS
1217 }
1218#endif
2d22c208 1219 return 0;
ae6a5609
EFL
1220
1221error:
1222 if (need_in)
1223 close_pair(fdin);
1224 else if (async->in)
1225 close(async->in);
1226
1227 if (need_out)
1228 close_pair(fdout);
1229 else if (async->out)
1230 close(async->out);
1231 return -1;
2d22c208
JS
1232}
1233
1234int finish_async(struct async *async)
1235{
f6b60983 1236#ifdef NO_PTHREADS
507d7804 1237 return wait_or_whine(async->pid, "child process", 0);
618ebe9f 1238#else
200a76b7
JS
1239 void *ret = (void *)(intptr_t)(-1);
1240
1241 if (pthread_join(async->tid, &ret))
1242 error("pthread_join failed");
1243 return (int)(intptr_t)ret;
618ebe9f 1244#endif
2d22c208 1245}
ae98a008 1246
dcf69262 1247const char *find_hook(const char *name)
5a7da2dc 1248{
03f2c773 1249 static struct strbuf path = STRBUF_INIT;
5a7da2dc 1250
03f2c773 1251 strbuf_reset(&path);
9445b492 1252 strbuf_git_path(&path, "hooks/%s", name);
235be51f 1253 if (access(path.buf, X_OK) < 0) {
f805a00a
DM
1254 int err = errno;
1255
235be51f
JS
1256#ifdef STRIP_EXTENSION
1257 strbuf_addstr(&path, STRIP_EXTENSION);
1258 if (access(path.buf, X_OK) >= 0)
1259 return path.buf;
f805a00a
DM
1260 if (errno == EACCES)
1261 err = errno;
235be51f 1262#endif
f805a00a
DM
1263
1264 if (err == EACCES && advice_ignored_hook) {
1265 static struct string_list advise_given = STRING_LIST_INIT_DUP;
1266
1267 if (!string_list_lookup(&advise_given, name)) {
1268 string_list_insert(&advise_given, name);
1269 advise(_("The '%s' hook was ignored because "
1270 "it's not set as executable.\n"
1271 "You can disable this warning with "
1272 "`git config advice.ignoredHook false`."),
1273 path.buf);
1274 }
1275 }
03f2c773 1276 return NULL;
235be51f 1277 }
03f2c773 1278 return path.buf;
5a7da2dc
AS
1279}
1280
15048f8a 1281int run_hook_ve(const char *const *env, const char *name, va_list args)
ae98a008 1282{
d3180279 1283 struct child_process hook = CHILD_PROCESS_INIT;
15048f8a 1284 const char *p;
ae98a008 1285
5a7da2dc
AS
1286 p = find_hook(name);
1287 if (!p)
cf94ca8e
SB
1288 return 0;
1289
d1d09456
RS
1290 argv_array_push(&hook.args, p);
1291 while ((p = va_arg(args, const char *)))
1292 argv_array_push(&hook.args, p);
15048f8a 1293 hook.env = env;
ae98a008
SB
1294 hook.no_stdin = 1;
1295 hook.stdout_to_stderr = 1;
ae98a008 1296
d1d09456 1297 return run_command(&hook);
ae98a008 1298}
15048f8a
BP
1299
1300int run_hook_le(const char *const *env, const char *name, ...)
1301{
1302 va_list args;
1303 int ret;
1304
1305 va_start(args, name);
1306 ret = run_hook_ve(env, name, args);
1307 va_end(args);
1308
1309 return ret;
1310}
911ec99b 1311
96335bcf
JK
1312struct io_pump {
1313 /* initialized by caller */
1314 int fd;
1315 int type; /* POLLOUT or POLLIN */
1316 union {
1317 struct {
1318 const char *buf;
1319 size_t len;
1320 } out;
1321 struct {
1322 struct strbuf *buf;
1323 size_t hint;
1324 } in;
1325 } u;
1326
1327 /* returned by pump_io */
1328 int error; /* 0 for success, otherwise errno */
1329
1330 /* internal use */
1331 struct pollfd *pfd;
1332};
1333
1334static int pump_io_round(struct io_pump *slots, int nr, struct pollfd *pfd)
1335{
1336 int pollsize = 0;
1337 int i;
1338
1339 for (i = 0; i < nr; i++) {
1340 struct io_pump *io = &slots[i];
1341 if (io->fd < 0)
1342 continue;
1343 pfd[pollsize].fd = io->fd;
1344 pfd[pollsize].events = io->type;
1345 io->pfd = &pfd[pollsize++];
1346 }
1347
1348 if (!pollsize)
1349 return 0;
1350
1351 if (poll(pfd, pollsize, -1) < 0) {
1352 if (errno == EINTR)
1353 return 1;
1354 die_errno("poll failed");
1355 }
1356
1357 for (i = 0; i < nr; i++) {
1358 struct io_pump *io = &slots[i];
1359
1360 if (io->fd < 0)
1361 continue;
1362
1363 if (!(io->pfd->revents & (POLLOUT|POLLIN|POLLHUP|POLLERR|POLLNVAL)))
1364 continue;
1365
1366 if (io->type == POLLOUT) {
1367 ssize_t len = xwrite(io->fd,
1368 io->u.out.buf, io->u.out.len);
1369 if (len < 0) {
1370 io->error = errno;
1371 close(io->fd);
1372 io->fd = -1;
1373 } else {
1374 io->u.out.buf += len;
1375 io->u.out.len -= len;
1376 if (!io->u.out.len) {
1377 close(io->fd);
1378 io->fd = -1;
1379 }
1380 }
1381 }
1382
1383 if (io->type == POLLIN) {
1384 ssize_t len = strbuf_read_once(io->u.in.buf,
1385 io->fd, io->u.in.hint);
1386 if (len < 0)
1387 io->error = errno;
1388 if (len <= 0) {
1389 close(io->fd);
1390 io->fd = -1;
1391 }
1392 }
1393 }
1394
1395 return 1;
1396}
1397
1398static int pump_io(struct io_pump *slots, int nr)
911ec99b 1399{
96335bcf
JK
1400 struct pollfd *pfd;
1401 int i;
1402
1403 for (i = 0; i < nr; i++)
1404 slots[i].error = 0;
1405
1406 ALLOC_ARRAY(pfd, nr);
1407 while (pump_io_round(slots, nr, pfd))
1408 ; /* nothing */
1409 free(pfd);
1410
1411 /* There may be multiple errno values, so just pick the first. */
1412 for (i = 0; i < nr; i++) {
1413 if (slots[i].error) {
1414 errno = slots[i].error;
1415 return -1;
1416 }
1417 }
1418 return 0;
1419}
1420
1421
1422int pipe_command(struct child_process *cmd,
1423 const char *in, size_t in_len,
1424 struct strbuf *out, size_t out_hint,
1425 struct strbuf *err, size_t err_hint)
1426{
1427 struct io_pump io[3];
1428 int nr = 0;
1429
1430 if (in)
1431 cmd->in = -1;
1432 if (out)
1433 cmd->out = -1;
1434 if (err)
1435 cmd->err = -1;
1436
911ec99b
JK
1437 if (start_command(cmd) < 0)
1438 return -1;
1439
96335bcf
JK
1440 if (in) {
1441 io[nr].fd = cmd->in;
1442 io[nr].type = POLLOUT;
1443 io[nr].u.out.buf = in;
1444 io[nr].u.out.len = in_len;
1445 nr++;
1446 }
1447 if (out) {
1448 io[nr].fd = cmd->out;
1449 io[nr].type = POLLIN;
1450 io[nr].u.in.buf = out;
1451 io[nr].u.in.hint = out_hint;
1452 nr++;
1453 }
1454 if (err) {
1455 io[nr].fd = cmd->err;
1456 io[nr].type = POLLIN;
1457 io[nr].u.in.buf = err;
1458 io[nr].u.in.hint = err_hint;
1459 nr++;
1460 }
1461
1462 if (pump_io(io, nr) < 0) {
911ec99b
JK
1463 finish_command(cmd); /* throw away exit code */
1464 return -1;
1465 }
1466
911ec99b
JK
1467 return finish_command(cmd);
1468}
c553c72e
SB
1469
1470enum child_state {
1471 GIT_CP_FREE,
1472 GIT_CP_WORKING,
1473 GIT_CP_WAIT_CLEANUP,
1474};
1475
1476struct parallel_processes {
1477 void *data;
1478
1479 int max_processes;
1480 int nr_processes;
1481
1482 get_next_task_fn get_next_task;
1483 start_failure_fn start_failure;
1484 task_finished_fn task_finished;
1485
1486 struct {
1487 enum child_state state;
1488 struct child_process process;
1489 struct strbuf err;
1490 void *data;
1491 } *children;
1492 /*
1493 * The struct pollfd is logically part of *children,
1494 * but the system call expects it as its own array.
1495 */
1496 struct pollfd *pfd;
1497
1498 unsigned shutdown : 1;
1499
1500 int output_owner;
1501 struct strbuf buffered_output; /* of finished children */
1502};
1503
aa710494 1504static int default_start_failure(struct strbuf *out,
c553c72e
SB
1505 void *pp_cb,
1506 void *pp_task_cb)
1507{
c553c72e
SB
1508 return 0;
1509}
1510
1511static int default_task_finished(int result,
aa710494 1512 struct strbuf *out,
c553c72e
SB
1513 void *pp_cb,
1514 void *pp_task_cb)
1515{
c553c72e
SB
1516 return 0;
1517}
1518
1519static void kill_children(struct parallel_processes *pp, int signo)
1520{
1521 int i, n = pp->max_processes;
1522
1523 for (i = 0; i < n; i++)
1524 if (pp->children[i].state == GIT_CP_WORKING)
1525 kill(pp->children[i].process.pid, signo);
1526}
1527
1528static struct parallel_processes *pp_for_signal;
1529
1530static void handle_children_on_signal(int signo)
1531{
1532 kill_children(pp_for_signal, signo);
1533 sigchain_pop(signo);
1534 raise(signo);
1535}
1536
1537static void pp_init(struct parallel_processes *pp,
1538 int n,
1539 get_next_task_fn get_next_task,
1540 start_failure_fn start_failure,
1541 task_finished_fn task_finished,
1542 void *data)
1543{
1544 int i;
1545
1546 if (n < 1)
1547 n = online_cpus();
1548
1549 pp->max_processes = n;
1550
1551 trace_printf("run_processes_parallel: preparing to run up to %d tasks", n);
1552
1553 pp->data = data;
1554 if (!get_next_task)
1555 die("BUG: you need to specify a get_next_task function");
1556 pp->get_next_task = get_next_task;
1557
1558 pp->start_failure = start_failure ? start_failure : default_start_failure;
1559 pp->task_finished = task_finished ? task_finished : default_task_finished;
1560
1561 pp->nr_processes = 0;
1562 pp->output_owner = 0;
1563 pp->shutdown = 0;
1564 pp->children = xcalloc(n, sizeof(*pp->children));
1565 pp->pfd = xcalloc(n, sizeof(*pp->pfd));
1566 strbuf_init(&pp->buffered_output, 0);
1567
1568 for (i = 0; i < n; i++) {
1569 strbuf_init(&pp->children[i].err, 0);
1570 child_process_init(&pp->children[i].process);
1571 pp->pfd[i].events = POLLIN | POLLHUP;
1572 pp->pfd[i].fd = -1;
1573 }
1574
1575 pp_for_signal = pp;
1576 sigchain_push_common(handle_children_on_signal);
1577}
1578
1579static void pp_cleanup(struct parallel_processes *pp)
1580{
1581 int i;
1582
1583 trace_printf("run_processes_parallel: done");
1584 for (i = 0; i < pp->max_processes; i++) {
1585 strbuf_release(&pp->children[i].err);
1586 child_process_clear(&pp->children[i].process);
1587 }
1588
1589 free(pp->children);
1590 free(pp->pfd);
1591
1592 /*
1593 * When get_next_task added messages to the buffer in its last
1594 * iteration, the buffered output is non empty.
1595 */
2dac9b56 1596 strbuf_write(&pp->buffered_output, stderr);
c553c72e
SB
1597 strbuf_release(&pp->buffered_output);
1598
1599 sigchain_pop_common();
1600}
1601
1602/* returns
1603 * 0 if a new task was started.
1604 * 1 if no new jobs was started (get_next_task ran out of work, non critical
1605 * problem with starting a new command)
1606 * <0 no new job was started, user wishes to shutdown early. Use negative code
1607 * to signal the children.
1608 */
1609static int pp_start_one(struct parallel_processes *pp)
1610{
1611 int i, code;
1612
1613 for (i = 0; i < pp->max_processes; i++)
1614 if (pp->children[i].state == GIT_CP_FREE)
1615 break;
1616 if (i == pp->max_processes)
1617 die("BUG: bookkeeping is hard");
1618
1619 code = pp->get_next_task(&pp->children[i].process,
1620 &pp->children[i].err,
1621 pp->data,
1622 &pp->children[i].data);
1623 if (!code) {
1624 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1625 strbuf_reset(&pp->children[i].err);
1626 return 1;
1627 }
1628 pp->children[i].process.err = -1;
1629 pp->children[i].process.stdout_to_stderr = 1;
1630 pp->children[i].process.no_stdin = 1;
1631
1632 if (start_command(&pp->children[i].process)) {
2a73b3da 1633 code = pp->start_failure(&pp->children[i].err,
c553c72e 1634 pp->data,
c1e860f1 1635 pp->children[i].data);
c553c72e
SB
1636 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1637 strbuf_reset(&pp->children[i].err);
1638 if (code)
1639 pp->shutdown = 1;
1640 return code;
1641 }
1642
1643 pp->nr_processes++;
1644 pp->children[i].state = GIT_CP_WORKING;
1645 pp->pfd[i].fd = pp->children[i].process.err;
1646 return 0;
1647}
1648
1649static void pp_buffer_stderr(struct parallel_processes *pp, int output_timeout)
1650{
1651 int i;
1652
1653 while ((i = poll(pp->pfd, pp->max_processes, output_timeout)) < 0) {
1654 if (errno == EINTR)
1655 continue;
1656 pp_cleanup(pp);
1657 die_errno("poll");
1658 }
1659
1660 /* Buffer output from all pipes. */
1661 for (i = 0; i < pp->max_processes; i++) {
1662 if (pp->children[i].state == GIT_CP_WORKING &&
1663 pp->pfd[i].revents & (POLLIN | POLLHUP)) {
1664 int n = strbuf_read_once(&pp->children[i].err,
1665 pp->children[i].process.err, 0);
1666 if (n == 0) {
1667 close(pp->children[i].process.err);
1668 pp->children[i].state = GIT_CP_WAIT_CLEANUP;
1669 } else if (n < 0)
1670 if (errno != EAGAIN)
1671 die_errno("read");
1672 }
1673 }
1674}
1675
1676static void pp_output(struct parallel_processes *pp)
1677{
1678 int i = pp->output_owner;
1679 if (pp->children[i].state == GIT_CP_WORKING &&
1680 pp->children[i].err.len) {
2dac9b56 1681 strbuf_write(&pp->children[i].err, stderr);
c553c72e
SB
1682 strbuf_reset(&pp->children[i].err);
1683 }
1684}
1685
1686static int pp_collect_finished(struct parallel_processes *pp)
1687{
1688 int i, code;
1689 int n = pp->max_processes;
1690 int result = 0;
1691
1692 while (pp->nr_processes > 0) {
1693 for (i = 0; i < pp->max_processes; i++)
1694 if (pp->children[i].state == GIT_CP_WAIT_CLEANUP)
1695 break;
1696 if (i == pp->max_processes)
1697 break;
1698
1699 code = finish_command(&pp->children[i].process);
1700
2a73b3da 1701 code = pp->task_finished(code,
c553c72e 1702 &pp->children[i].err, pp->data,
c1e860f1 1703 pp->children[i].data);
c553c72e
SB
1704
1705 if (code)
1706 result = code;
1707 if (code < 0)
1708 break;
1709
1710 pp->nr_processes--;
1711 pp->children[i].state = GIT_CP_FREE;
1712 pp->pfd[i].fd = -1;
1713 child_process_init(&pp->children[i].process);
1714
1715 if (i != pp->output_owner) {
1716 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1717 strbuf_reset(&pp->children[i].err);
1718 } else {
2dac9b56 1719 strbuf_write(&pp->children[i].err, stderr);
c553c72e
SB
1720 strbuf_reset(&pp->children[i].err);
1721
1722 /* Output all other finished child processes */
2dac9b56 1723 strbuf_write(&pp->buffered_output, stderr);
c553c72e
SB
1724 strbuf_reset(&pp->buffered_output);
1725
1726 /*
1727 * Pick next process to output live.
1728 * NEEDSWORK:
1729 * For now we pick it randomly by doing a round
1730 * robin. Later we may want to pick the one with
1731 * the most output or the longest or shortest
1732 * running process time.
1733 */
1734 for (i = 0; i < n; i++)
1735 if (pp->children[(pp->output_owner + i) % n].state == GIT_CP_WORKING)
1736 break;
1737 pp->output_owner = (pp->output_owner + i) % n;
1738 }
1739 }
1740 return result;
1741}
1742
1743int run_processes_parallel(int n,
1744 get_next_task_fn get_next_task,
1745 start_failure_fn start_failure,
1746 task_finished_fn task_finished,
1747 void *pp_cb)
1748{
1749 int i, code;
1750 int output_timeout = 100;
1751 int spawn_cap = 4;
1752 struct parallel_processes pp;
1753
1754 pp_init(&pp, n, get_next_task, start_failure, task_finished, pp_cb);
1755 while (1) {
1756 for (i = 0;
1757 i < spawn_cap && !pp.shutdown &&
1758 pp.nr_processes < pp.max_processes;
1759 i++) {
1760 code = pp_start_one(&pp);
1761 if (!code)
1762 continue;
1763 if (code < 0) {
1764 pp.shutdown = 1;
1765 kill_children(&pp, -code);
1766 }
1767 break;
1768 }
1769 if (!pp.nr_processes)
1770 break;
1771 pp_buffer_stderr(&pp, output_timeout);
1772 pp_output(&pp);
1773 code = pp_collect_finished(&pp);
1774 if (code) {
1775 pp.shutdown = 1;
1776 if (code < 0)
1777 kill_children(&pp, -code);
1778 }
1779 }
1780
1781 pp_cleanup(&pp);
1782 return 0;
1783}