trace2: Documentation/technical/api-trace2.txt
[git/git.git] / run-command.c
CommitLineData
b1bf95bb
JW
1#include "cache.h"
2#include "run-command.h"
d807c4a0 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 $PATH
233 * lookups in that case.
234 *
235 * The reassignment of EACCES to errno looks like a no-op below,
236 * but we need to protect against exists_in_PATH overwriting errno.
237 */
238 if (errno == EACCES && !strchr(file, '/'))
239 errno = exists_in_PATH(file) ? EACCES : ENOENT;
a7855083
JH
240 else if (errno == ENOTDIR && !strchr(file, '/'))
241 errno = ENOENT;
38f865c2
JK
242 return -1;
243}
244
20574f55 245static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
8dba1e63 246{
20574f55 247 if (!argv[0])
033abf97 248 BUG("shell command is empty");
8dba1e63 249
f445644f 250 if (strcspn(argv[0], "|&;<>()$`\\\"' \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 382
321fd823 383static int prepare_cmd(struct argv_array *out, const struct child_process *cmd)
3967e25b
BW
384{
385 if (!cmd->argv[0])
033abf97 386 BUG("command is empty");
3967e25b 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
321fd823
JK
406 * are '/' characters, we have exec attempt to invoke the command
407 * directly.
e3a43446
BW
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;
321fd823
JK
414 } else {
415 argv_array_clear(out);
416 errno = ENOENT;
417 return -1;
e3a43446
BW
418 }
419 }
321fd823
JK
420
421 return 0;
3967e25b 422}
ae25394b
BW
423
424static char **prep_childenv(const char *const *deltaenv)
425{
426 extern char **environ;
427 char **childenv;
428 struct string_list env = STRING_LIST_INIT_DUP;
429 struct strbuf key = STRBUF_INIT;
430 const char *const *p;
431 int i;
432
433 /* Construct a sorted string list consisting of the current environ */
434 for (p = (const char *const *) environ; p && *p; p++) {
435 const char *equals = strchr(*p, '=');
436
437 if (equals) {
438 strbuf_reset(&key);
439 strbuf_add(&key, *p, equals - *p);
440 string_list_append(&env, key.buf)->util = (void *) *p;
441 } else {
442 string_list_append(&env, *p)->util = (void *) *p;
443 }
444 }
445 string_list_sort(&env);
446
447 /* Merge in 'deltaenv' with the current environ */
448 for (p = deltaenv; p && *p; p++) {
449 const char *equals = strchr(*p, '=');
450
451 if (equals) {
452 /* ('key=value'), insert or replace entry */
453 strbuf_reset(&key);
454 strbuf_add(&key, *p, equals - *p);
455 string_list_insert(&env, key.buf)->util = (void *) *p;
456 } else {
457 /* otherwise ('key') remove existing entry */
458 string_list_remove(&env, *p, 0);
459 }
460 }
461
462 /* Create an array of 'char *' to be used as the childenv */
0e187d75 463 ALLOC_ARRAY(childenv, env.nr + 1);
ae25394b
BW
464 for (i = 0; i < env.nr; i++)
465 childenv[i] = env.items[i].util;
466 childenv[env.nr] = NULL;
467
468 string_list_clear(&env, 0);
469 strbuf_release(&key);
470 return childenv;
471}
45afb1ca
EW
472
473struct atfork_state {
474#ifndef NO_PTHREADS
475 int cs;
476#endif
477 sigset_t old;
478};
479
dde74d73
JS
480#define CHECK_BUG(err, msg) \
481 do { \
482 int e = (err); \
483 if (e) \
484 BUG("%s: %s", msg, strerror(e)); \
485 } while(0)
45afb1ca
EW
486
487static void atfork_prepare(struct atfork_state *as)
488{
489 sigset_t all;
490
491 if (sigfillset(&all))
492 die_errno("sigfillset");
493#ifdef NO_PTHREADS
494 if (sigprocmask(SIG_SETMASK, &all, &as->old))
495 die_errno("sigprocmask");
496#else
dde74d73 497 CHECK_BUG(pthread_sigmask(SIG_SETMASK, &all, &as->old),
45afb1ca 498 "blocking all signals");
dde74d73 499 CHECK_BUG(pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &as->cs),
45afb1ca
EW
500 "disabling cancellation");
501#endif
502}
503
504static void atfork_parent(struct atfork_state *as)
505{
506#ifdef NO_PTHREADS
507 if (sigprocmask(SIG_SETMASK, &as->old, NULL))
508 die_errno("sigprocmask");
509#else
dde74d73 510 CHECK_BUG(pthread_setcancelstate(as->cs, NULL),
45afb1ca 511 "re-enabling cancellation");
dde74d73 512 CHECK_BUG(pthread_sigmask(SIG_SETMASK, &as->old, NULL),
45afb1ca 513 "restoring signal mask");
200a76b7 514#endif
45afb1ca
EW
515}
516#endif /* GIT_WINDOWS_NATIVE */
a5487ddf
JS
517
518static inline void set_cloexec(int fd)
519{
520 int flags = fcntl(fd, F_GETFD);
521 if (flags >= 0)
522 fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
523}
a5487ddf 524
507d7804 525static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
ab0b41da
JS
526{
527 int status, code = -1;
528 pid_t waiting;
529 int failed_errno = 0;
530
531 while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
532 ; /* nothing */
507d7804
TI
533 if (in_signal)
534 return 0;
ab0b41da
JS
535
536 if (waiting < 0) {
537 failed_errno = errno;
fbcb0e06 538 error_errno("waitpid for %s failed", argv0);
ab0b41da
JS
539 } else if (waiting != pid) {
540 error("waitpid is confused (%s)", argv0);
541 } else if (WIFSIGNALED(status)) {
542 code = WTERMSIG(status);
ac78663b 543 if (code != SIGINT && code != SIGQUIT && code != SIGPIPE)
a2767c5c 544 error("%s died of signal %d", argv0, code);
ab0b41da
JS
545 /*
546 * This return value is chosen so that code & 0xff
547 * mimics the exit code that a POSIX shell would report for
548 * a program that died from this signal.
549 */
709ca730 550 code += 128;
ab0b41da
JS
551 } else if (WIFEXITED(status)) {
552 code = WEXITSTATUS(status);
ab0b41da
JS
553 } else {
554 error("waitpid is confused (%s)", argv0);
555 }
afe19ff7
JK
556
557 clear_child_for_cleanup(pid);
558
ab0b41da
JS
559 errno = failed_errno;
560 return code;
561}
562
c61a975d
NTND
563static void trace_add_env(struct strbuf *dst, const char *const *deltaenv)
564{
565 struct string_list envs = STRING_LIST_INIT_DUP;
566 const char *const *e;
567 int i;
568 int printed_unset = 0;
569
570 /* Last one wins, see run-command.c:prep_childenv() for context */
571 for (e = deltaenv; e && *e; e++) {
572 struct strbuf key = STRBUF_INIT;
573 char *equals = strchr(*e, '=');
574
575 if (equals) {
576 strbuf_add(&key, *e, equals - *e);
577 string_list_insert(&envs, key.buf)->util = equals + 1;
578 } else {
579 string_list_insert(&envs, *e)->util = NULL;
580 }
581 strbuf_release(&key);
582 }
583
584 /* "unset X Y...;" */
585 for (i = 0; i < envs.nr; i++) {
586 const char *var = envs.items[i].string;
587 const char *val = envs.items[i].util;
588
589 if (val || !getenv(var))
590 continue;
591
592 if (!printed_unset) {
593 strbuf_addstr(dst, " unset");
594 printed_unset = 1;
595 }
596 strbuf_addf(dst, " %s", var);
597 }
598 if (printed_unset)
599 strbuf_addch(dst, ';');
600
601 /* ... followed by "A=B C=D ..." */
602 for (i = 0; i < envs.nr; i++) {
603 const char *var = envs.items[i].string;
604 const char *val = envs.items[i].util;
605 const char *oldval;
606
607 if (!val)
608 continue;
609
610 oldval = getenv(var);
611 if (oldval && !strcmp(val, oldval))
612 continue;
613
614 strbuf_addf(dst, " %s=", var);
615 sq_quote_buf_pretty(dst, val);
616 }
617 string_list_clear(&envs, 0);
618}
619
e73dd786
NTND
620static void trace_run_command(const struct child_process *cp)
621{
622 struct strbuf buf = STRBUF_INIT;
623
624 if (!trace_want(&trace_default_key))
625 return;
626
248f66ed 627 strbuf_addstr(&buf, "trace: run_command:");
090a0927
NTND
628 if (cp->dir) {
629 strbuf_addstr(&buf, " cd ");
630 sq_quote_buf_pretty(&buf, cp->dir);
631 strbuf_addch(&buf, ';');
632 }
c61a975d
NTND
633 /*
634 * The caller is responsible for initializing cp->env from
635 * cp->env_array if needed. We only check one place.
636 */
637 if (cp->env)
638 trace_add_env(&buf, cp->env);
21dfc5e0
NTND
639 if (cp->git_cmd)
640 strbuf_addstr(&buf, " git");
e73dd786
NTND
641 sq_quote_argv_pretty(&buf, cp->argv);
642
643 trace_printf("%s", buf.buf);
644 strbuf_release(&buf);
645}
646
ebcb5d16 647int start_command(struct child_process *cmd)
b1bf95bb 648{
f3b33f1d
JS
649 int need_in, need_out, need_err;
650 int fdin[2], fdout[2], fderr[2];
25043d8a 651 int failed_errno;
939296c4 652 char *str;
4919bf03 653
c460c0ec
JK
654 if (!cmd->argv)
655 cmd->argv = cmd->args.argv;
19a583dc
RS
656 if (!cmd->env)
657 cmd->env = cmd->env_array.argv;
c460c0ec 658
c20181e3
JS
659 /*
660 * In case of errors we must keep the promise to close FDs
661 * that have been passed in via ->in and ->out.
662 */
663
e4507ae8 664 need_in = !cmd->no_stdin && cmd->in < 0;
4919bf03 665 if (need_in) {
c20181e3 666 if (pipe(fdin) < 0) {
0ac77ec3 667 failed_errno = errno;
c20181e3
JS
668 if (cmd->out > 0)
669 close(cmd->out);
939296c4 670 str = "standard input";
0ac77ec3 671 goto fail_pipe;
c20181e3 672 }
4919bf03 673 cmd->in = fdin[1];
4919bf03
SP
674 }
675
e4507ae8
SP
676 need_out = !cmd->no_stdout
677 && !cmd->stdout_to_stderr
678 && cmd->out < 0;
f4bba25b
SP
679 if (need_out) {
680 if (pipe(fdout) < 0) {
0ac77ec3 681 failed_errno = errno;
f4bba25b
SP
682 if (need_in)
683 close_pair(fdin);
c20181e3
JS
684 else if (cmd->in)
685 close(cmd->in);
939296c4 686 str = "standard output";
0ac77ec3 687 goto fail_pipe;
f4bba25b
SP
688 }
689 cmd->out = fdout[0];
f4bba25b
SP
690 }
691
b73a4397 692 need_err = !cmd->no_stderr && cmd->err < 0;
f3b33f1d
JS
693 if (need_err) {
694 if (pipe(fderr) < 0) {
0ac77ec3 695 failed_errno = errno;
f3b33f1d
JS
696 if (need_in)
697 close_pair(fdin);
c20181e3
JS
698 else if (cmd->in)
699 close(cmd->in);
f3b33f1d
JS
700 if (need_out)
701 close_pair(fdout);
c20181e3
JS
702 else if (cmd->out)
703 close(cmd->out);
939296c4 704 str = "standard error";
0ac77ec3 705fail_pipe:
939296c4
SB
706 error("cannot create %s pipe for %s: %s",
707 str, cmd->argv[0], strerror(failed_errno));
2d71608e 708 child_process_clear(cmd);
0ac77ec3
JS
709 errno = failed_errno;
710 return -1;
f3b33f1d
JS
711 }
712 cmd->err = fderr[0];
713 }
714
e73dd786
NTND
715 trace_run_command(cmd);
716
13af8cbd 717 fflush(NULL);
8852f5d7 718
380395d0 719#ifndef GIT_WINDOWS_NATIVE
2b541bf8
JS
720{
721 int notify_pipe[2];
db015a28 722 int null_fd = -1;
ae25394b 723 char **childenv;
3967e25b 724 struct argv_array argv = ARGV_ARRAY_INIT;
79319b19 725 struct child_err cerr;
45afb1ca 726 struct atfork_state as;
3967e25b 727
321fd823
JK
728 if (prepare_cmd(&argv, cmd) < 0) {
729 failed_errno = errno;
730 cmd->pid = -1;
e5a329a2
JH
731 if (!cmd->silent_exec_failure)
732 error_errno("cannot run %s", cmd->argv[0]);
321fd823
JK
733 goto end_of_spawn;
734 }
735
2b541bf8
JS
736 if (pipe(notify_pipe))
737 notify_pipe[0] = notify_pipe[1] = -1;
738
db015a28
BW
739 if (cmd->no_stdin || cmd->no_stdout || cmd->no_stderr) {
740 null_fd = open("/dev/null", O_RDWR | O_CLOEXEC);
741 if (null_fd < 0)
742 die_errno(_("open /dev/null failed"));
743 set_cloexec(null_fd);
744 }
745
ae25394b 746 childenv = prep_childenv(cmd->env);
45afb1ca 747 atfork_prepare(&as);
3967e25b 748
e503cd6e
BW
749 /*
750 * NOTE: In order to prevent deadlocking when using threads special
751 * care should be taken with the function calls made in between the
752 * fork() and exec() calls. No calls should be made to functions which
753 * require acquiring a lock (e.g. malloc) as the lock could have been
754 * held by another thread at the time of forking, causing the lock to
755 * never be released in the child process. This means only
756 * Async-Signal-Safe functions are permitted in the child.
757 */
ebcb5d16 758 cmd->pid = fork();
25043d8a 759 failed_errno = errno;
ebcb5d16 760 if (!cmd->pid) {
45afb1ca 761 int sig;
a5487ddf 762 /*
79319b19
BW
763 * Ensure the default die/error/warn routines do not get
764 * called, they can take stdio locks and malloc.
a5487ddf 765 */
79319b19
BW
766 set_die_routine(child_die_fn);
767 set_error_routine(child_error_fn);
768 set_warn_routine(child_warn_fn);
a5487ddf 769
2b541bf8
JS
770 close(notify_pipe[0]);
771 set_cloexec(notify_pipe[1]);
772 child_notifier = notify_pipe[1];
2b541bf8 773
e4507ae8 774 if (cmd->no_stdin)
53fa6753 775 child_dup2(null_fd, 0);
e4507ae8 776 else if (need_in) {
53fa6753
BW
777 child_dup2(fdin[0], 0);
778 child_close_pair(fdin);
4919bf03 779 } else if (cmd->in) {
53fa6753
BW
780 child_dup2(cmd->in, 0);
781 child_close(cmd->in);
95d3c4f5 782 }
4919bf03 783
ce2cf27a 784 if (cmd->no_stderr)
53fa6753 785 child_dup2(null_fd, 2);
ce2cf27a 786 else if (need_err) {
53fa6753
BW
787 child_dup2(fderr[1], 2);
788 child_close_pair(fderr);
4f41b611 789 } else if (cmd->err > 1) {
53fa6753
BW
790 child_dup2(cmd->err, 2);
791 child_close(cmd->err);
ce2cf27a
CC
792 }
793
e4507ae8 794 if (cmd->no_stdout)
53fa6753 795 child_dup2(null_fd, 1);
e4507ae8 796 else if (cmd->stdout_to_stderr)
53fa6753 797 child_dup2(2, 1);
f4bba25b 798 else if (need_out) {
53fa6753
BW
799 child_dup2(fdout[1], 1);
800 child_close_pair(fdout);
f4bba25b 801 } else if (cmd->out > 1) {
53fa6753
BW
802 child_dup2(cmd->out, 1);
803 child_close(cmd->out);
f4bba25b
SP
804 }
805
1568fea0 806 if (cmd->dir && chdir(cmd->dir))
79319b19 807 child_die(CHILD_ERR_CHDIR);
3967e25b 808
45afb1ca
EW
809 /*
810 * restore default signal handlers here, in case
811 * we catch a signal right before execve below
812 */
813 for (sig = 1; sig < NSIG; sig++) {
814 /* ignored signals get reset to SIG_DFL on execve */
815 if (signal(sig, SIG_DFL) == SIG_IGN)
816 signal(sig, SIG_IGN);
817 }
818
819 if (sigprocmask(SIG_SETMASK, &as.old, NULL) != 0)
820 child_die(CHILD_ERR_SIGPROCMASK);
821
e3a43446
BW
822 /*
823 * Attempt to exec using the command and arguments starting at
824 * argv.argv[1]. argv.argv[0] contains SHELL_PATH which will
825 * be used in the event exec failed with ENOEXEC at which point
826 * we will try to interpret the command using 'sh'.
827 */
ae25394b
BW
828 execve(argv.argv[1], (char *const *) argv.argv + 1,
829 (char *const *) childenv);
e3a43446 830 if (errno == ENOEXEC)
ae25394b
BW
831 execve(argv.argv[0], (char *const *) argv.argv,
832 (char *const *) childenv);
3967e25b 833
fc1b56f0 834 if (errno == ENOENT) {
79319b19
BW
835 if (cmd->silent_exec_failure)
836 child_die(CHILD_ERR_SILENT);
837 child_die(CHILD_ERR_ENOENT);
fc1b56f0 838 } else {
79319b19 839 child_die(CHILD_ERR_ERRNO);
fc1b56f0 840 }
b1bf95bb 841 }
45afb1ca 842 atfork_parent(&as);
0ac77ec3 843 if (cmd->pid < 0)
fbcb0e06 844 error_errno("cannot fork() for %s", cmd->argv[0]);
afe19ff7 845 else if (cmd->clean_on_exit)
ac2fbaa6 846 mark_child_for_cleanup(cmd->pid, cmd);
2b541bf8
JS
847
848 /*
3967e25b 849 * Wait for child's exec. If the exec succeeds (or if fork()
2b541bf8 850 * failed), EOF is seen immediately by the parent. Otherwise, the
79319b19 851 * child process sends a child_err struct.
2b541bf8
JS
852 * Note that use of this infrastructure is completely advisory,
853 * therefore, we keep error checks minimal.
854 */
855 close(notify_pipe[1]);
79319b19 856 if (xread(notify_pipe[0], &cerr, sizeof(cerr)) == sizeof(cerr)) {
2b541bf8 857 /*
3967e25b 858 * At this point we know that fork() succeeded, but exec()
2b541bf8
JS
859 * failed. Errors have been reported to our stderr.
860 */
507d7804 861 wait_or_whine(cmd->pid, cmd->argv[0], 0);
79319b19 862 child_err_spew(cmd, &cerr);
2b541bf8
JS
863 failed_errno = errno;
864 cmd->pid = -1;
865 }
866 close(notify_pipe[0]);
3967e25b 867
db015a28
BW
868 if (null_fd >= 0)
869 close(null_fd);
3967e25b 870 argv_array_clear(&argv);
ae25394b 871 free(childenv);
2b541bf8 872}
321fd823
JK
873end_of_spawn:
874
ba26f296 875#else
0d30ad71 876{
75301f90 877 int fhin = 0, fhout = 1, fherr = 2;
108ac313 878 const char **sargv = cmd->argv;
20574f55 879 struct argv_array nargv = ARGV_ARRAY_INIT;
ba26f296 880
75301f90
JS
881 if (cmd->no_stdin)
882 fhin = open("/dev/null", O_RDWR);
883 else if (need_in)
884 fhin = dup(fdin[0]);
885 else if (cmd->in)
886 fhin = dup(cmd->in);
887
888 if (cmd->no_stderr)
889 fherr = open("/dev/null", O_RDWR);
890 else if (need_err)
891 fherr = dup(fderr[1]);
76d44c8c
JH
892 else if (cmd->err > 2)
893 fherr = dup(cmd->err);
75301f90
JS
894
895 if (cmd->no_stdout)
896 fhout = open("/dev/null", O_RDWR);
897 else if (cmd->stdout_to_stderr)
898 fhout = dup(fherr);
899 else if (need_out)
900 fhout = dup(fdout[1]);
901 else if (cmd->out > 1)
902 fhout = dup(cmd->out);
ba26f296 903
5a50085c 904 if (cmd->git_cmd)
20574f55 905 cmd->argv = prepare_git_cmd(&nargv, cmd->argv);
5a50085c 906 else if (cmd->use_shell)
20574f55 907 cmd->argv = prepare_shell_cmd(&nargv, cmd->argv);
ba26f296 908
77734da2
KB
909 cmd->pid = mingw_spawnvpe(cmd->argv[0], cmd->argv, (char**) cmd->env,
910 cmd->dir, fhin, fhout, fherr);
0ac77ec3 911 failed_errno = errno;
c024beb5 912 if (cmd->pid < 0 && (!cmd->silent_exec_failure || errno != ENOENT))
fbcb0e06 913 error_errno("cannot spawn %s", cmd->argv[0]);
afe19ff7 914 if (cmd->clean_on_exit && cmd->pid >= 0)
ac2fbaa6 915 mark_child_for_cleanup(cmd->pid, cmd);
ba26f296 916
20574f55 917 argv_array_clear(&nargv);
108ac313 918 cmd->argv = sargv;
75301f90
JS
919 if (fhin != 0)
920 close(fhin);
921 if (fhout != 1)
922 close(fhout);
923 if (fherr != 2)
924 close(fherr);
0d30ad71 925}
ba26f296
JS
926#endif
927
928 if (cmd->pid < 0) {
929 if (need_in)
930 close_pair(fdin);
931 else if (cmd->in)
932 close(cmd->in);
933 if (need_out)
934 close_pair(fdout);
935 else if (cmd->out)
936 close(cmd->out);
937 if (need_err)
938 close_pair(fderr);
fc012c28
D
939 else if (cmd->err)
940 close(cmd->err);
2d71608e 941 child_process_clear(cmd);
0ac77ec3
JS
942 errno = failed_errno;
943 return -1;
ba26f296 944 }
4919bf03
SP
945
946 if (need_in)
947 close(fdin[0]);
948 else if (cmd->in)
949 close(cmd->in);
950
f4bba25b
SP
951 if (need_out)
952 close(fdout[1]);
c20181e3 953 else if (cmd->out)
f4bba25b
SP
954 close(cmd->out);
955
f3b33f1d
JS
956 if (need_err)
957 close(fderr[1]);
4f41b611
SP
958 else if (cmd->err)
959 close(cmd->err);
f3b33f1d 960
ebcb5d16
SP
961 return 0;
962}
963
2d22c208
JS
964int finish_command(struct child_process *cmd)
965{
507d7804 966 int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
2d71608e 967 child_process_clear(cmd);
c460c0ec 968 return ret;
2d22c208
JS
969}
970
507d7804
TI
971int finish_command_in_signal(struct child_process *cmd)
972{
973 return wait_or_whine(cmd->pid, cmd->argv[0], 1);
974}
975
976
ebcb5d16
SP
977int run_command(struct child_process *cmd)
978{
c29b3962
JK
979 int code;
980
981 if (cmd->out < 0 || cmd->err < 0)
033abf97 982 BUG("run_command with a pipe can cause deadlock");
c29b3962
JK
983
984 code = start_command(cmd);
ebcb5d16
SP
985 if (code)
986 return code;
987 return finish_command(cmd);
988}
989
f1000898
SP
990int run_command_v_opt(const char **argv, int opt)
991{
41e9bad7 992 return run_command_v_opt_cd_env(argv, opt, NULL, NULL);
1568fea0
AR
993}
994
ee493148
AR
995int run_command_v_opt_cd_env(const char **argv, int opt, const char *dir, const char *const *env)
996{
1f87293d
RS
997 struct child_process cmd = CHILD_PROCESS_INIT;
998 cmd.argv = argv;
999 cmd.no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
1000 cmd.git_cmd = opt & RUN_GIT_CMD ? 1 : 0;
1001 cmd.stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
1002 cmd.silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
1003 cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
1004 cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
ee493148
AR
1005 cmd.dir = dir;
1006 cmd.env = env;
1007 return run_command(&cmd);
1008}
2d22c208 1009
f6b60983 1010#ifndef NO_PTHREADS
0ea1c89b
JS
1011static pthread_t main_thread;
1012static int main_thread_set;
1013static pthread_key_t async_key;
1ece66bc 1014static pthread_key_t async_die_counter;
0ea1c89b 1015
200a76b7 1016static void *run_thread(void *data)
618ebe9f
JS
1017{
1018 struct async *async = data;
f6b60983 1019 intptr_t ret;
0ea1c89b 1020
c792d7b6
JK
1021 if (async->isolate_sigpipe) {
1022 sigset_t mask;
1023 sigemptyset(&mask);
1024 sigaddset(&mask, SIGPIPE);
1025 if (pthread_sigmask(SIG_BLOCK, &mask, NULL) < 0) {
1026 ret = error("unable to block SIGPIPE in async thread");
1027 return (void *)ret;
1028 }
1029 }
1030
0ea1c89b 1031 pthread_setspecific(async_key, async);
f6b60983 1032 ret = async->proc(async->proc_in, async->proc_out, async->data);
200a76b7 1033 return (void *)ret;
618ebe9f 1034}
0ea1c89b
JS
1035
1036static NORETURN void die_async(const char *err, va_list params)
1037{
1038 vreportf("fatal: ", err, params);
1039
661a8cf4 1040 if (in_async()) {
0ea1c89b
JS
1041 struct async *async = pthread_getspecific(async_key);
1042 if (async->proc_in >= 0)
1043 close(async->proc_in);
1044 if (async->proc_out >= 0)
1045 close(async->proc_out);
1046 pthread_exit((void *)128);
1047 }
1048
1049 exit(128);
618ebe9f 1050}
1ece66bc
JK
1051
1052static int async_die_is_recursing(void)
1053{
1054 void *ret = pthread_getspecific(async_die_counter);
1055 pthread_setspecific(async_die_counter, (void *)1);
1056 return ret != NULL;
1057}
1058
661a8cf4
JK
1059int in_async(void)
1060{
1061 if (!main_thread_set)
1062 return 0; /* no asyncs started yet */
1063 return !pthread_equal(main_thread, pthread_self());
1064}
1065
b992fe10 1066static void NORETURN async_exit(int code)
9658846c
JK
1067{
1068 pthread_exit((void *)(intptr_t)code);
1069}
1070
0f4b6db3
EB
1071#else
1072
1073static struct {
1074 void (**handlers)(void);
1075 size_t nr;
1076 size_t alloc;
1077} git_atexit_hdlrs;
1078
1079static int git_atexit_installed;
1080
6066a7ea 1081static void git_atexit_dispatch(void)
0f4b6db3
EB
1082{
1083 size_t i;
1084
1085 for (i=git_atexit_hdlrs.nr ; i ; i--)
1086 git_atexit_hdlrs.handlers[i-1]();
1087}
1088
6066a7ea 1089static void git_atexit_clear(void)
0f4b6db3
EB
1090{
1091 free(git_atexit_hdlrs.handlers);
1092 memset(&git_atexit_hdlrs, 0, sizeof(git_atexit_hdlrs));
1093 git_atexit_installed = 0;
1094}
1095
1096#undef atexit
1097int git_atexit(void (*handler)(void))
1098{
1099 ALLOC_GROW(git_atexit_hdlrs.handlers, git_atexit_hdlrs.nr + 1, git_atexit_hdlrs.alloc);
1100 git_atexit_hdlrs.handlers[git_atexit_hdlrs.nr++] = handler;
1101 if (!git_atexit_installed) {
1102 if (atexit(&git_atexit_dispatch))
1103 return -1;
1104 git_atexit_installed = 1;
1105 }
1106 return 0;
1107}
1108#define atexit git_atexit
1109
661a8cf4
JK
1110static int process_is_async;
1111int in_async(void)
1112{
1113 return process_is_async;
1114}
1115
b992fe10 1116static void NORETURN async_exit(int code)
9658846c
JK
1117{
1118 exit(code);
1119}
1120
618ebe9f
JS
1121#endif
1122
b992fe10
LS
1123void check_pipe(int err)
1124{
1125 if (err == EPIPE) {
1126 if (in_async())
1127 async_exit(141);
1128
1129 signal(SIGPIPE, SIG_DFL);
1130 raise(SIGPIPE);
1131 /* Should never happen, but just in case... */
1132 exit(141);
1133 }
1134}
1135
2d22c208
JS
1136int start_async(struct async *async)
1137{
ae6a5609
EFL
1138 int need_in, need_out;
1139 int fdin[2], fdout[2];
1140 int proc_in, proc_out;
2d22c208 1141
ae6a5609
EFL
1142 need_in = async->in < 0;
1143 if (need_in) {
1144 if (pipe(fdin) < 0) {
1145 if (async->out > 0)
1146 close(async->out);
fbcb0e06 1147 return error_errno("cannot create pipe");
ae6a5609
EFL
1148 }
1149 async->in = fdin[1];
1150 }
1151
1152 need_out = async->out < 0;
1153 if (need_out) {
1154 if (pipe(fdout) < 0) {
1155 if (need_in)
1156 close_pair(fdin);
1157 else if (async->in)
1158 close(async->in);
fbcb0e06 1159 return error_errno("cannot create pipe");
ae6a5609
EFL
1160 }
1161 async->out = fdout[0];
1162 }
1163
1164 if (need_in)
1165 proc_in = fdin[0];
1166 else if (async->in)
1167 proc_in = async->in;
1168 else
1169 proc_in = -1;
1170
1171 if (need_out)
1172 proc_out = fdout[1];
1173 else if (async->out)
1174 proc_out = async->out;
1175 else
1176 proc_out = -1;
2d22c208 1177
f6b60983 1178#ifdef NO_PTHREADS
2c3766f0
AM
1179 /* Flush stdio before fork() to avoid cloning buffers */
1180 fflush(NULL);
1181
2d22c208
JS
1182 async->pid = fork();
1183 if (async->pid < 0) {
fbcb0e06 1184 error_errno("fork (async) failed");
ae6a5609 1185 goto error;
2d22c208
JS
1186 }
1187 if (!async->pid) {
ae6a5609
EFL
1188 if (need_in)
1189 close(fdin[1]);
1190 if (need_out)
1191 close(fdout[0]);
0f4b6db3 1192 git_atexit_clear();
661a8cf4 1193 process_is_async = 1;
ae6a5609 1194 exit(!!async->proc(proc_in, proc_out, async->data));
2d22c208 1195 }
ae6a5609 1196
ac2fbaa6 1197 mark_child_for_cleanup(async->pid, NULL);
afe19ff7 1198
ae6a5609
EFL
1199 if (need_in)
1200 close(fdin[0]);
1201 else if (async->in)
1202 close(async->in);
1203
1204 if (need_out)
1205 close(fdout[1]);
1206 else if (async->out)
1207 close(async->out);
618ebe9f 1208#else
0ea1c89b
JS
1209 if (!main_thread_set) {
1210 /*
1211 * We assume that the first time that start_async is called
1212 * it is from the main thread.
1213 */
1214 main_thread_set = 1;
1215 main_thread = pthread_self();
1216 pthread_key_create(&async_key, NULL);
1ece66bc 1217 pthread_key_create(&async_die_counter, NULL);
0ea1c89b 1218 set_die_routine(die_async);
1ece66bc 1219 set_die_is_recursing_routine(async_die_is_recursing);
0ea1c89b
JS
1220 }
1221
200a76b7
JS
1222 if (proc_in >= 0)
1223 set_cloexec(proc_in);
1224 if (proc_out >= 0)
1225 set_cloexec(proc_out);
ae6a5609
EFL
1226 async->proc_in = proc_in;
1227 async->proc_out = proc_out;
200a76b7
JS
1228 {
1229 int err = pthread_create(&async->tid, NULL, run_thread, async);
1230 if (err) {
2179045f 1231 error(_("cannot create async thread: %s"), strerror(err));
200a76b7
JS
1232 goto error;
1233 }
618ebe9f
JS
1234 }
1235#endif
2d22c208 1236 return 0;
ae6a5609
EFL
1237
1238error:
1239 if (need_in)
1240 close_pair(fdin);
1241 else if (async->in)
1242 close(async->in);
1243
1244 if (need_out)
1245 close_pair(fdout);
1246 else if (async->out)
1247 close(async->out);
1248 return -1;
2d22c208
JS
1249}
1250
1251int finish_async(struct async *async)
1252{
f6b60983 1253#ifdef NO_PTHREADS
507d7804 1254 return wait_or_whine(async->pid, "child process", 0);
618ebe9f 1255#else
200a76b7
JS
1256 void *ret = (void *)(intptr_t)(-1);
1257
1258 if (pthread_join(async->tid, &ret))
1259 error("pthread_join failed");
1260 return (int)(intptr_t)ret;
618ebe9f 1261#endif
2d22c208 1262}
ae98a008 1263
c0e40a2d
NTND
1264int async_with_fork(void)
1265{
1266#ifdef NO_PTHREADS
1267 return 1;
1268#else
1269 return 0;
1270#endif
1271}
1272
dcf69262 1273const char *find_hook(const char *name)
5a7da2dc 1274{
03f2c773 1275 static struct strbuf path = STRBUF_INIT;
5a7da2dc 1276
03f2c773 1277 strbuf_reset(&path);
9445b492 1278 strbuf_git_path(&path, "hooks/%s", name);
235be51f 1279 if (access(path.buf, X_OK) < 0) {
f805a00a
DM
1280 int err = errno;
1281
235be51f
JS
1282#ifdef STRIP_EXTENSION
1283 strbuf_addstr(&path, STRIP_EXTENSION);
1284 if (access(path.buf, X_OK) >= 0)
1285 return path.buf;
f805a00a
DM
1286 if (errno == EACCES)
1287 err = errno;
235be51f 1288#endif
f805a00a
DM
1289
1290 if (err == EACCES && advice_ignored_hook) {
1291 static struct string_list advise_given = STRING_LIST_INIT_DUP;
1292
1293 if (!string_list_lookup(&advise_given, name)) {
1294 string_list_insert(&advise_given, name);
1295 advise(_("The '%s' hook was ignored because "
1296 "it's not set as executable.\n"
1297 "You can disable this warning with "
1298 "`git config advice.ignoredHook false`."),
1299 path.buf);
1300 }
1301 }
03f2c773 1302 return NULL;
235be51f 1303 }
03f2c773 1304 return path.buf;
5a7da2dc
AS
1305}
1306
15048f8a 1307int run_hook_ve(const char *const *env, const char *name, va_list args)
ae98a008 1308{
d3180279 1309 struct child_process hook = CHILD_PROCESS_INIT;
15048f8a 1310 const char *p;
ae98a008 1311
5a7da2dc
AS
1312 p = find_hook(name);
1313 if (!p)
cf94ca8e
SB
1314 return 0;
1315
d1d09456
RS
1316 argv_array_push(&hook.args, p);
1317 while ((p = va_arg(args, const char *)))
1318 argv_array_push(&hook.args, p);
15048f8a 1319 hook.env = env;
ae98a008
SB
1320 hook.no_stdin = 1;
1321 hook.stdout_to_stderr = 1;
ae98a008 1322
d1d09456 1323 return run_command(&hook);
ae98a008 1324}
15048f8a
BP
1325
1326int run_hook_le(const char *const *env, const char *name, ...)
1327{
1328 va_list args;
1329 int ret;
1330
1331 va_start(args, name);
1332 ret = run_hook_ve(env, name, args);
1333 va_end(args);
1334
1335 return ret;
1336}
911ec99b 1337
96335bcf
JK
1338struct io_pump {
1339 /* initialized by caller */
1340 int fd;
1341 int type; /* POLLOUT or POLLIN */
1342 union {
1343 struct {
1344 const char *buf;
1345 size_t len;
1346 } out;
1347 struct {
1348 struct strbuf *buf;
1349 size_t hint;
1350 } in;
1351 } u;
1352
1353 /* returned by pump_io */
1354 int error; /* 0 for success, otherwise errno */
1355
1356 /* internal use */
1357 struct pollfd *pfd;
1358};
1359
1360static int pump_io_round(struct io_pump *slots, int nr, struct pollfd *pfd)
1361{
1362 int pollsize = 0;
1363 int i;
1364
1365 for (i = 0; i < nr; i++) {
1366 struct io_pump *io = &slots[i];
1367 if (io->fd < 0)
1368 continue;
1369 pfd[pollsize].fd = io->fd;
1370 pfd[pollsize].events = io->type;
1371 io->pfd = &pfd[pollsize++];
1372 }
1373
1374 if (!pollsize)
1375 return 0;
1376
1377 if (poll(pfd, pollsize, -1) < 0) {
1378 if (errno == EINTR)
1379 return 1;
1380 die_errno("poll failed");
1381 }
1382
1383 for (i = 0; i < nr; i++) {
1384 struct io_pump *io = &slots[i];
1385
1386 if (io->fd < 0)
1387 continue;
1388
1389 if (!(io->pfd->revents & (POLLOUT|POLLIN|POLLHUP|POLLERR|POLLNVAL)))
1390 continue;
1391
1392 if (io->type == POLLOUT) {
1393 ssize_t len = xwrite(io->fd,
1394 io->u.out.buf, io->u.out.len);
1395 if (len < 0) {
1396 io->error = errno;
1397 close(io->fd);
1398 io->fd = -1;
1399 } else {
1400 io->u.out.buf += len;
1401 io->u.out.len -= len;
1402 if (!io->u.out.len) {
1403 close(io->fd);
1404 io->fd = -1;
1405 }
1406 }
1407 }
1408
1409 if (io->type == POLLIN) {
1410 ssize_t len = strbuf_read_once(io->u.in.buf,
1411 io->fd, io->u.in.hint);
1412 if (len < 0)
1413 io->error = errno;
1414 if (len <= 0) {
1415 close(io->fd);
1416 io->fd = -1;
1417 }
1418 }
1419 }
1420
1421 return 1;
1422}
1423
1424static int pump_io(struct io_pump *slots, int nr)
911ec99b 1425{
96335bcf
JK
1426 struct pollfd *pfd;
1427 int i;
1428
1429 for (i = 0; i < nr; i++)
1430 slots[i].error = 0;
1431
1432 ALLOC_ARRAY(pfd, nr);
1433 while (pump_io_round(slots, nr, pfd))
1434 ; /* nothing */
1435 free(pfd);
1436
1437 /* There may be multiple errno values, so just pick the first. */
1438 for (i = 0; i < nr; i++) {
1439 if (slots[i].error) {
1440 errno = slots[i].error;
1441 return -1;
1442 }
1443 }
1444 return 0;
1445}
1446
1447
1448int pipe_command(struct child_process *cmd,
1449 const char *in, size_t in_len,
1450 struct strbuf *out, size_t out_hint,
1451 struct strbuf *err, size_t err_hint)
1452{
1453 struct io_pump io[3];
1454 int nr = 0;
1455
1456 if (in)
1457 cmd->in = -1;
1458 if (out)
1459 cmd->out = -1;
1460 if (err)
1461 cmd->err = -1;
1462
911ec99b
JK
1463 if (start_command(cmd) < 0)
1464 return -1;
1465
96335bcf
JK
1466 if (in) {
1467 io[nr].fd = cmd->in;
1468 io[nr].type = POLLOUT;
1469 io[nr].u.out.buf = in;
1470 io[nr].u.out.len = in_len;
1471 nr++;
1472 }
1473 if (out) {
1474 io[nr].fd = cmd->out;
1475 io[nr].type = POLLIN;
1476 io[nr].u.in.buf = out;
1477 io[nr].u.in.hint = out_hint;
1478 nr++;
1479 }
1480 if (err) {
1481 io[nr].fd = cmd->err;
1482 io[nr].type = POLLIN;
1483 io[nr].u.in.buf = err;
1484 io[nr].u.in.hint = err_hint;
1485 nr++;
1486 }
1487
1488 if (pump_io(io, nr) < 0) {
911ec99b
JK
1489 finish_command(cmd); /* throw away exit code */
1490 return -1;
1491 }
1492
911ec99b
JK
1493 return finish_command(cmd);
1494}
c553c72e
SB
1495
1496enum child_state {
1497 GIT_CP_FREE,
1498 GIT_CP_WORKING,
1499 GIT_CP_WAIT_CLEANUP,
1500};
1501
1502struct parallel_processes {
1503 void *data;
1504
1505 int max_processes;
1506 int nr_processes;
1507
1508 get_next_task_fn get_next_task;
1509 start_failure_fn start_failure;
1510 task_finished_fn task_finished;
1511
1512 struct {
1513 enum child_state state;
1514 struct child_process process;
1515 struct strbuf err;
1516 void *data;
1517 } *children;
1518 /*
1519 * The struct pollfd is logically part of *children,
1520 * but the system call expects it as its own array.
1521 */
1522 struct pollfd *pfd;
1523
1524 unsigned shutdown : 1;
1525
1526 int output_owner;
1527 struct strbuf buffered_output; /* of finished children */
1528};
1529
aa710494 1530static int default_start_failure(struct strbuf *out,
c553c72e
SB
1531 void *pp_cb,
1532 void *pp_task_cb)
1533{
c553c72e
SB
1534 return 0;
1535}
1536
1537static int default_task_finished(int result,
aa710494 1538 struct strbuf *out,
c553c72e
SB
1539 void *pp_cb,
1540 void *pp_task_cb)
1541{
c553c72e
SB
1542 return 0;
1543}
1544
1545static void kill_children(struct parallel_processes *pp, int signo)
1546{
1547 int i, n = pp->max_processes;
1548
1549 for (i = 0; i < n; i++)
1550 if (pp->children[i].state == GIT_CP_WORKING)
1551 kill(pp->children[i].process.pid, signo);
1552}
1553
1554static struct parallel_processes *pp_for_signal;
1555
1556static void handle_children_on_signal(int signo)
1557{
1558 kill_children(pp_for_signal, signo);
1559 sigchain_pop(signo);
1560 raise(signo);
1561}
1562
1563static void pp_init(struct parallel_processes *pp,
1564 int n,
1565 get_next_task_fn get_next_task,
1566 start_failure_fn start_failure,
1567 task_finished_fn task_finished,
1568 void *data)
1569{
1570 int i;
1571
1572 if (n < 1)
1573 n = online_cpus();
1574
1575 pp->max_processes = n;
1576
1577 trace_printf("run_processes_parallel: preparing to run up to %d tasks", n);
1578
1579 pp->data = data;
1580 if (!get_next_task)
033abf97 1581 BUG("you need to specify a get_next_task function");
c553c72e
SB
1582 pp->get_next_task = get_next_task;
1583
1584 pp->start_failure = start_failure ? start_failure : default_start_failure;
1585 pp->task_finished = task_finished ? task_finished : default_task_finished;
1586
1587 pp->nr_processes = 0;
1588 pp->output_owner = 0;
1589 pp->shutdown = 0;
1590 pp->children = xcalloc(n, sizeof(*pp->children));
1591 pp->pfd = xcalloc(n, sizeof(*pp->pfd));
1592 strbuf_init(&pp->buffered_output, 0);
1593
1594 for (i = 0; i < n; i++) {
1595 strbuf_init(&pp->children[i].err, 0);
1596 child_process_init(&pp->children[i].process);
1597 pp->pfd[i].events = POLLIN | POLLHUP;
1598 pp->pfd[i].fd = -1;
1599 }
1600
1601 pp_for_signal = pp;
1602 sigchain_push_common(handle_children_on_signal);
1603}
1604
1605static void pp_cleanup(struct parallel_processes *pp)
1606{
1607 int i;
1608
1609 trace_printf("run_processes_parallel: done");
1610 for (i = 0; i < pp->max_processes; i++) {
1611 strbuf_release(&pp->children[i].err);
1612 child_process_clear(&pp->children[i].process);
1613 }
1614
1615 free(pp->children);
1616 free(pp->pfd);
1617
1618 /*
1619 * When get_next_task added messages to the buffer in its last
1620 * iteration, the buffered output is non empty.
1621 */
2dac9b56 1622 strbuf_write(&pp->buffered_output, stderr);
c553c72e
SB
1623 strbuf_release(&pp->buffered_output);
1624
1625 sigchain_pop_common();
1626}
1627
1628/* returns
1629 * 0 if a new task was started.
1630 * 1 if no new jobs was started (get_next_task ran out of work, non critical
1631 * problem with starting a new command)
1632 * <0 no new job was started, user wishes to shutdown early. Use negative code
1633 * to signal the children.
1634 */
1635static int pp_start_one(struct parallel_processes *pp)
1636{
1637 int i, code;
1638
1639 for (i = 0; i < pp->max_processes; i++)
1640 if (pp->children[i].state == GIT_CP_FREE)
1641 break;
1642 if (i == pp->max_processes)
033abf97 1643 BUG("bookkeeping is hard");
c553c72e
SB
1644
1645 code = pp->get_next_task(&pp->children[i].process,
1646 &pp->children[i].err,
1647 pp->data,
1648 &pp->children[i].data);
1649 if (!code) {
1650 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1651 strbuf_reset(&pp->children[i].err);
1652 return 1;
1653 }
1654 pp->children[i].process.err = -1;
1655 pp->children[i].process.stdout_to_stderr = 1;
1656 pp->children[i].process.no_stdin = 1;
1657
1658 if (start_command(&pp->children[i].process)) {
2a73b3da 1659 code = pp->start_failure(&pp->children[i].err,
c553c72e 1660 pp->data,
c1e860f1 1661 pp->children[i].data);
c553c72e
SB
1662 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1663 strbuf_reset(&pp->children[i].err);
1664 if (code)
1665 pp->shutdown = 1;
1666 return code;
1667 }
1668
1669 pp->nr_processes++;
1670 pp->children[i].state = GIT_CP_WORKING;
1671 pp->pfd[i].fd = pp->children[i].process.err;
1672 return 0;
1673}
1674
1675static void pp_buffer_stderr(struct parallel_processes *pp, int output_timeout)
1676{
1677 int i;
1678
1679 while ((i = poll(pp->pfd, pp->max_processes, output_timeout)) < 0) {
1680 if (errno == EINTR)
1681 continue;
1682 pp_cleanup(pp);
1683 die_errno("poll");
1684 }
1685
1686 /* Buffer output from all pipes. */
1687 for (i = 0; i < pp->max_processes; i++) {
1688 if (pp->children[i].state == GIT_CP_WORKING &&
1689 pp->pfd[i].revents & (POLLIN | POLLHUP)) {
1690 int n = strbuf_read_once(&pp->children[i].err,
1691 pp->children[i].process.err, 0);
1692 if (n == 0) {
1693 close(pp->children[i].process.err);
1694 pp->children[i].state = GIT_CP_WAIT_CLEANUP;
1695 } else if (n < 0)
1696 if (errno != EAGAIN)
1697 die_errno("read");
1698 }
1699 }
1700}
1701
1702static void pp_output(struct parallel_processes *pp)
1703{
1704 int i = pp->output_owner;
1705 if (pp->children[i].state == GIT_CP_WORKING &&
1706 pp->children[i].err.len) {
2dac9b56 1707 strbuf_write(&pp->children[i].err, stderr);
c553c72e
SB
1708 strbuf_reset(&pp->children[i].err);
1709 }
1710}
1711
1712static int pp_collect_finished(struct parallel_processes *pp)
1713{
1714 int i, code;
1715 int n = pp->max_processes;
1716 int result = 0;
1717
1718 while (pp->nr_processes > 0) {
1719 for (i = 0; i < pp->max_processes; i++)
1720 if (pp->children[i].state == GIT_CP_WAIT_CLEANUP)
1721 break;
1722 if (i == pp->max_processes)
1723 break;
1724
1725 code = finish_command(&pp->children[i].process);
1726
2a73b3da 1727 code = pp->task_finished(code,
c553c72e 1728 &pp->children[i].err, pp->data,
c1e860f1 1729 pp->children[i].data);
c553c72e
SB
1730
1731 if (code)
1732 result = code;
1733 if (code < 0)
1734 break;
1735
1736 pp->nr_processes--;
1737 pp->children[i].state = GIT_CP_FREE;
1738 pp->pfd[i].fd = -1;
1739 child_process_init(&pp->children[i].process);
1740
1741 if (i != pp->output_owner) {
1742 strbuf_addbuf(&pp->buffered_output, &pp->children[i].err);
1743 strbuf_reset(&pp->children[i].err);
1744 } else {
2dac9b56 1745 strbuf_write(&pp->children[i].err, stderr);
c553c72e
SB
1746 strbuf_reset(&pp->children[i].err);
1747
1748 /* Output all other finished child processes */
2dac9b56 1749 strbuf_write(&pp->buffered_output, stderr);
c553c72e
SB
1750 strbuf_reset(&pp->buffered_output);
1751
1752 /*
1753 * Pick next process to output live.
1754 * NEEDSWORK:
1755 * For now we pick it randomly by doing a round
1756 * robin. Later we may want to pick the one with
1757 * the most output or the longest or shortest
1758 * running process time.
1759 */
1760 for (i = 0; i < n; i++)
1761 if (pp->children[(pp->output_owner + i) % n].state == GIT_CP_WORKING)
1762 break;
1763 pp->output_owner = (pp->output_owner + i) % n;
1764 }
1765 }
1766 return result;
1767}
1768
1769int run_processes_parallel(int n,
1770 get_next_task_fn get_next_task,
1771 start_failure_fn start_failure,
1772 task_finished_fn task_finished,
1773 void *pp_cb)
1774{
1775 int i, code;
1776 int output_timeout = 100;
1777 int spawn_cap = 4;
1778 struct parallel_processes pp;
1779
1780 pp_init(&pp, n, get_next_task, start_failure, task_finished, pp_cb);
1781 while (1) {
1782 for (i = 0;
1783 i < spawn_cap && !pp.shutdown &&
1784 pp.nr_processes < pp.max_processes;
1785 i++) {
1786 code = pp_start_one(&pp);
1787 if (!code)
1788 continue;
1789 if (code < 0) {
1790 pp.shutdown = 1;
1791 kill_children(&pp, -code);
1792 }
1793 break;
1794 }
1795 if (!pp.nr_processes)
1796 break;
1797 pp_buffer_stderr(&pp, output_timeout);
1798 pp_output(&pp);
1799 code = pp_collect_finished(&pp);
1800 if (code) {
1801 pp.shutdown = 1;
1802 if (code < 0)
1803 kill_children(&pp, -code);
1804 }
1805 }
1806
1807 pp_cleanup(&pp);
1808 return 0;
1809}