xread: retry after poll on EAGAIN/EWOULDBLOCK
[git/git.git] / wrapper.c
CommitLineData
112db553
LT
1/*
2 * Various trivial helper wrappers around standard functions
3 */
4#include "cache.h"
5
e0500293 6static void do_nothing(size_t size)
a9a74636 7{
a9a74636
NP
8}
9
e0500293 10static void (*try_to_free_routine)(size_t size) = do_nothing;
a9a74636 11
f8bb1d94 12static int memory_limit_check(size_t size, int gentle)
d41489a6 13{
9927d962
SP
14 static size_t limit = 0;
15 if (!limit) {
16 limit = git_env_ulong("GIT_ALLOC_LIMIT", 0);
17 if (!limit)
18 limit = SIZE_MAX;
d41489a6 19 }
f0d89001 20 if (size > limit) {
f8bb1d94 21 if (gentle) {
f0d89001
JH
22 error("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
23 (uintmax_t)size, (uintmax_t)limit);
f8bb1d94
NTND
24 return -1;
25 } else
f0d89001
JH
26 die("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
27 (uintmax_t)size, (uintmax_t)limit);
f8bb1d94
NTND
28 }
29 return 0;
d41489a6
NTND
30}
31
851c34b0 32try_to_free_t set_try_to_free_routine(try_to_free_t routine)
a9a74636 33{
851c34b0 34 try_to_free_t old = try_to_free_routine;
00b0d7f7
JH
35 if (!routine)
36 routine = do_nothing;
851c34b0
JS
37 try_to_free_routine = routine;
38 return old;
a9a74636
NP
39}
40
112db553
LT
41char *xstrdup(const char *str)
42{
43 char *ret = strdup(str);
44 if (!ret) {
a9a74636 45 try_to_free_routine(strlen(str) + 1);
112db553
LT
46 ret = strdup(str);
47 if (!ret)
48 die("Out of memory, strdup failed");
49 }
50 return ret;
51}
52
f8bb1d94 53static void *do_xmalloc(size_t size, int gentle)
112db553 54{
d41489a6
NTND
55 void *ret;
56
f8bb1d94
NTND
57 if (memory_limit_check(size, gentle))
58 return NULL;
d41489a6 59 ret = malloc(size);
112db553
LT
60 if (!ret && !size)
61 ret = malloc(1);
62 if (!ret) {
a9a74636 63 try_to_free_routine(size);
112db553
LT
64 ret = malloc(size);
65 if (!ret && !size)
66 ret = malloc(1);
f8bb1d94
NTND
67 if (!ret) {
68 if (!gentle)
69 die("Out of memory, malloc failed (tried to allocate %lu bytes)",
70 (unsigned long)size);
71 else {
72 error("Out of memory, malloc failed (tried to allocate %lu bytes)",
73 (unsigned long)size);
74 return NULL;
75 }
76 }
112db553
LT
77 }
78#ifdef XMALLOC_POISON
79 memset(ret, 0xA5, size);
80#endif
81 return ret;
82}
83
f8bb1d94
NTND
84void *xmalloc(size_t size)
85{
86 return do_xmalloc(size, 0);
87}
88
89static void *do_xmallocz(size_t size, int gentle)
5bf9219d
IL
90{
91 void *ret;
f8bb1d94
NTND
92 if (unsigned_add_overflows(size, 1)) {
93 if (gentle) {
94 error("Data too large to fit into virtual memory space.");
95 return NULL;
96 } else
97 die("Data too large to fit into virtual memory space.");
98 }
99 ret = do_xmalloc(size + 1, gentle);
100 if (ret)
101 ((char*)ret)[size] = 0;
5bf9219d
IL
102 return ret;
103}
104
f8bb1d94
NTND
105void *xmallocz(size_t size)
106{
107 return do_xmallocz(size, 0);
108}
109
110void *xmallocz_gently(size_t size)
111{
112 return do_xmallocz(size, 1);
113}
114
112db553
LT
115/*
116 * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
117 * "data" to the allocated memory, zero terminates the allocated memory,
118 * and returns a pointer to the allocated memory. If the allocation fails,
119 * the program dies.
120 */
121void *xmemdupz(const void *data, size_t len)
122{
5bf9219d 123 return memcpy(xmallocz(len), data, len);
112db553
LT
124}
125
126char *xstrndup(const char *str, size_t len)
127{
128 char *p = memchr(str, '\0', len);
129 return xmemdupz(str, p ? p - str : len);
130}
131
132void *xrealloc(void *ptr, size_t size)
133{
d41489a6
NTND
134 void *ret;
135
f8bb1d94 136 memory_limit_check(size, 0);
d41489a6 137 ret = realloc(ptr, size);
112db553
LT
138 if (!ret && !size)
139 ret = realloc(ptr, 1);
140 if (!ret) {
a9a74636 141 try_to_free_routine(size);
112db553
LT
142 ret = realloc(ptr, size);
143 if (!ret && !size)
144 ret = realloc(ptr, 1);
145 if (!ret)
146 die("Out of memory, realloc failed");
147 }
148 return ret;
149}
150
151void *xcalloc(size_t nmemb, size_t size)
152{
d41489a6
NTND
153 void *ret;
154
f8bb1d94 155 memory_limit_check(size * nmemb, 0);
d41489a6 156 ret = calloc(nmemb, size);
112db553
LT
157 if (!ret && (!nmemb || !size))
158 ret = calloc(1, 1);
159 if (!ret) {
a9a74636 160 try_to_free_routine(nmemb * size);
112db553
LT
161 ret = calloc(nmemb, size);
162 if (!ret && (!nmemb || !size))
163 ret = calloc(1, 1);
164 if (!ret)
165 die("Out of memory, calloc failed");
166 }
167 return ret;
168}
169
0b6806b9
SP
170/*
171 * Limit size of IO chunks, because huge chunks only cause pain. OS X
172 * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
382d20e3 173 * the absence of bugs, large chunks can result in bad latencies when
0b6806b9 174 * you decide to kill the process.
a983e6ac
JH
175 *
176 * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
177 * that is smaller than that, clip it to SSIZE_MAX, as a call to
178 * read(2) or write(2) larger than that is allowed to fail. As the last
179 * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
180 * to override this, if the definition of SSIZE_MAX given by the platform
181 * is broken.
0b6806b9 182 */
a983e6ac
JH
183#ifndef MAX_IO_SIZE
184# define MAX_IO_SIZE_DEFAULT (8*1024*1024)
185# if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
186# define MAX_IO_SIZE SSIZE_MAX
187# else
188# define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
189# endif
190#endif
0b6806b9 191
3ff53df7
PT
192/**
193 * xopen() is the same as open(), but it die()s if the open() fails.
194 */
195int xopen(const char *path, int oflag, ...)
196{
197 mode_t mode = 0;
198 va_list ap;
199
200 /*
201 * va_arg() will have undefined behavior if the specified type is not
202 * compatible with the argument type. Since integers are promoted to
203 * ints, we fetch the next argument as an int, and then cast it to a
204 * mode_t to avoid undefined behavior.
205 */
206 va_start(ap, oflag);
207 if (oflag & O_CREAT)
208 mode = va_arg(ap, int);
209 va_end(ap);
210
211 for (;;) {
212 int fd = open(path, oflag, mode);
213 if (fd >= 0)
214 return fd;
215 if (errno == EINTR)
216 continue;
217
218 if ((oflag & O_RDWR) == O_RDWR)
219 die_errno(_("could not open '%s' for reading and writing"), path);
220 else if ((oflag & O_WRONLY) == O_WRONLY)
221 die_errno(_("could not open '%s' for writing"), path);
222 else
223 die_errno(_("could not open '%s' for reading"), path);
224 }
225}
226
112db553
LT
227/*
228 * xread() is the same a read(), but it automatically restarts read()
229 * operations with a recoverable error (EAGAIN and EINTR). xread()
230 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
231 */
232ssize_t xread(int fd, void *buf, size_t len)
233{
234 ssize_t nr;
0b6806b9
SP
235 if (len > MAX_IO_SIZE)
236 len = MAX_IO_SIZE;
112db553
LT
237 while (1) {
238 nr = read(fd, buf, len);
1079c4be
SB
239 if (nr < 0) {
240 if (errno == EINTR)
241 continue;
242 if (errno == EAGAIN || errno == EWOULDBLOCK) {
243 struct pollfd pfd;
244 pfd.events = POLLIN;
245 pfd.fd = fd;
246 /*
247 * it is OK if this poll() failed; we
248 * want to leave this infinite loop
249 * only when read() returns with
250 * success, or an expected failure,
251 * which would be checked by the next
252 * call to read(2).
253 */
254 poll(&pfd, 1, -1);
c22f6202 255 continue;
1079c4be
SB
256 }
257 }
112db553
LT
258 return nr;
259 }
260}
261
262/*
263 * xwrite() is the same a write(), but it automatically restarts write()
264 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
265 * GUARANTEE that "len" bytes is written even if the operation is successful.
266 */
267ssize_t xwrite(int fd, const void *buf, size_t len)
268{
269 ssize_t nr;
0b6806b9
SP
270 if (len > MAX_IO_SIZE)
271 len = MAX_IO_SIZE;
112db553
LT
272 while (1) {
273 nr = write(fd, buf, len);
274 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
9aa91af0
YM
275 continue;
276 return nr;
277 }
278}
279
280/*
281 * xpread() is the same as pread(), but it automatically restarts pread()
282 * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
283 * NOT GUARANTEE that "len" bytes is read even if the data is available.
284 */
285ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
286{
287 ssize_t nr;
288 if (len > MAX_IO_SIZE)
289 len = MAX_IO_SIZE;
290 while (1) {
291 nr = pread(fd, buf, len, offset);
292 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
112db553
LT
293 continue;
294 return nr;
295 }
296}
297
559e840b
JH
298ssize_t read_in_full(int fd, void *buf, size_t count)
299{
300 char *p = buf;
301 ssize_t total = 0;
302
303 while (count > 0) {
304 ssize_t loaded = xread(fd, p, count);
56d7c27a
JK
305 if (loaded < 0)
306 return -1;
307 if (loaded == 0)
308 return total;
559e840b
JH
309 count -= loaded;
310 p += loaded;
311 total += loaded;
312 }
313
314 return total;
315}
316
317ssize_t write_in_full(int fd, const void *buf, size_t count)
318{
319 const char *p = buf;
320 ssize_t total = 0;
321
322 while (count > 0) {
323 ssize_t written = xwrite(fd, p, count);
324 if (written < 0)
325 return -1;
326 if (!written) {
327 errno = ENOSPC;
328 return -1;
329 }
330 count -= written;
331 p += written;
332 total += written;
333 }
334
335 return total;
336}
337
426ddeea
YM
338ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
339{
340 char *p = buf;
341 ssize_t total = 0;
342
343 while (count > 0) {
344 ssize_t loaded = xpread(fd, p, count, offset);
345 if (loaded < 0)
346 return -1;
347 if (loaded == 0)
348 return total;
349 count -= loaded;
350 p += loaded;
351 total += loaded;
352 offset += loaded;
353 }
354
355 return total;
356}
357
112db553
LT
358int xdup(int fd)
359{
360 int ret = dup(fd);
361 if (ret < 0)
d824cbba 362 die_errno("dup failed");
112db553
LT
363 return ret;
364}
365
260eec29
PT
366/**
367 * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
368 */
369FILE *xfopen(const char *path, const char *mode)
370{
371 for (;;) {
372 FILE *fp = fopen(path, mode);
373 if (fp)
374 return fp;
375 if (errno == EINTR)
376 continue;
377
378 if (*mode && mode[1] == '+')
379 die_errno(_("could not open '%s' for reading and writing"), path);
380 else if (*mode == 'w' || *mode == 'a')
381 die_errno(_("could not open '%s' for writing"), path);
382 else
383 die_errno(_("could not open '%s' for reading"), path);
384 }
385}
386
112db553
LT
387FILE *xfdopen(int fd, const char *mode)
388{
389 FILE *stream = fdopen(fd, mode);
390 if (stream == NULL)
d824cbba 391 die_errno("Out of memory? fdopen failed");
112db553
LT
392 return stream;
393}
394
395int xmkstemp(char *template)
396{
397 int fd;
6cf6bb3e
AE
398 char origtemplate[PATH_MAX];
399 strlcpy(origtemplate, template, sizeof(origtemplate));
112db553
LT
400
401 fd = mkstemp(template);
6cf6bb3e
AE
402 if (fd < 0) {
403 int saved_errno = errno;
404 const char *nonrelative_template;
405
f7be59b4 406 if (strlen(template) != strlen(origtemplate))
6cf6bb3e
AE
407 template = origtemplate;
408
e2a57aac 409 nonrelative_template = absolute_path(template);
6cf6bb3e
AE
410 errno = saved_errno;
411 die_errno("Unable to create temporary file '%s'",
412 nonrelative_template);
413 }
112db553
LT
414 return fd;
415}
39c68542 416
33f23936
JN
417/* git_mkstemp() - create tmp file honoring TMPDIR variable */
418int git_mkstemp(char *path, size_t len, const char *template)
419{
420 const char *tmp;
421 size_t n;
422
423 tmp = getenv("TMPDIR");
424 if (!tmp)
425 tmp = "/tmp";
426 n = snprintf(path, len, "%s/%s", tmp, template);
427 if (len <= n) {
428 errno = ENAMETOOLONG;
429 return -1;
430 }
431 return mkstemp(path);
432}
433
434/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
435int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
436{
437 const char *tmp;
438 size_t n;
439
440 tmp = getenv("TMPDIR");
441 if (!tmp)
442 tmp = "/tmp";
443 n = snprintf(path, len, "%s/%s", tmp, template);
444 if (len <= n) {
445 errno = ENAMETOOLONG;
446 return -1;
447 }
448 return mkstemps(path, suffix_len);
449}
450
451/* Adapted from libiberty's mkstemp.c. */
452
453#undef TMP_MAX
454#define TMP_MAX 16384
455
456int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
457{
458 static const char letters[] =
459 "abcdefghijklmnopqrstuvwxyz"
460 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
461 "0123456789";
462 static const int num_letters = 62;
463 uint64_t value;
464 struct timeval tv;
465 char *template;
466 size_t len;
467 int fd, count;
468
469 len = strlen(pattern);
470
471 if (len < 6 + suffix_len) {
472 errno = EINVAL;
473 return -1;
474 }
475
476 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
477 errno = EINVAL;
478 return -1;
479 }
480
481 /*
482 * Replace pattern's XXXXXX characters with randomness.
483 * Try TMP_MAX different filenames.
484 */
485 gettimeofday(&tv, NULL);
486 value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
487 template = &pattern[len - 6 - suffix_len];
488 for (count = 0; count < TMP_MAX; ++count) {
489 uint64_t v = value;
490 /* Fill in the random bits. */
491 template[0] = letters[v % num_letters]; v /= num_letters;
492 template[1] = letters[v % num_letters]; v /= num_letters;
493 template[2] = letters[v % num_letters]; v /= num_letters;
494 template[3] = letters[v % num_letters]; v /= num_letters;
495 template[4] = letters[v % num_letters]; v /= num_letters;
496 template[5] = letters[v % num_letters]; v /= num_letters;
497
498 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
a2cb86c1 499 if (fd >= 0)
33f23936
JN
500 return fd;
501 /*
502 * Fatal error (EPERM, ENOSPC etc).
503 * It doesn't make sense to loop.
504 */
505 if (errno != EEXIST)
506 break;
507 /*
508 * This is a random value. It is only necessary that
509 * the next TMP_MAX values generated by adding 7777 to
510 * VALUE are different with (module 2^32).
511 */
512 value += 7777;
513 }
514 /* We return the null string if we can't find a unique file name. */
515 pattern[0] = '\0';
516 return -1;
517}
518
519int git_mkstemp_mode(char *pattern, int mode)
520{
521 /* mkstemp is just mkstemps with no suffix */
522 return git_mkstemps_mode(pattern, 0, mode);
523}
524
ec145c9c 525#ifdef NO_MKSTEMPS
33f23936
JN
526int gitmkstemps(char *pattern, int suffix_len)
527{
528 return git_mkstemps_mode(pattern, suffix_len, 0600);
529}
ec145c9c 530#endif
33f23936 531
b862b61c
MM
532int xmkstemp_mode(char *template, int mode)
533{
534 int fd;
6cf6bb3e
AE
535 char origtemplate[PATH_MAX];
536 strlcpy(origtemplate, template, sizeof(origtemplate));
b862b61c
MM
537
538 fd = git_mkstemp_mode(template, mode);
6cf6bb3e
AE
539 if (fd < 0) {
540 int saved_errno = errno;
541 const char *nonrelative_template;
542
543 if (!template[0])
544 template = origtemplate;
545
e2a57aac 546 nonrelative_template = absolute_path(template);
6cf6bb3e
AE
547 errno = saved_errno;
548 die_errno("Unable to create temporary file '%s'",
549 nonrelative_template);
550 }
b862b61c
MM
551 return fd;
552}
553
10e13ec8 554static int warn_if_unremovable(const char *op, const char *file, int rc)
fc71db39 555{
1054af7d
RS
556 int err;
557 if (!rc || errno == ENOENT)
558 return 0;
559 err = errno;
560 warning("unable to %s %s: %s", op, file, strerror(errno));
561 errno = err;
fc71db39
AR
562 return rc;
563}
564
9ccc0c08
RS
565int unlink_or_msg(const char *file, struct strbuf *err)
566{
567 int rc = unlink(file);
568
569 assert(err);
570
571 if (!rc || errno == ENOENT)
572 return 0;
573
574 strbuf_addf(err, "unable to unlink %s: %s",
575 file, strerror(errno));
576 return -1;
577}
578
10e13ec8
PC
579int unlink_or_warn(const char *file)
580{
581 return warn_if_unremovable("unlink", file, unlink(file));
582}
d1723296
PC
583
584int rmdir_or_warn(const char *file)
585{
586 return warn_if_unremovable("rmdir", file, rmdir(file));
587}
80d706af
PC
588
589int remove_or_warn(unsigned int mode, const char *file)
590{
591 return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
592}
2f705875 593
55b38a48
JH
594void warn_on_inaccessible(const char *path)
595{
596 warning(_("unable to access '%s': %s"), path, strerror(errno));
597}
598
4698c8fe
JN
599static int access_error_is_ok(int err, unsigned flag)
600{
601 return err == ENOENT || err == ENOTDIR ||
602 ((flag & ACCESS_EACCES_OK) && err == EACCES);
603}
604
605int access_or_warn(const char *path, int mode, unsigned flag)
ba8bd830
JK
606{
607 int ret = access(path, mode);
4698c8fe 608 if (ret && !access_error_is_ok(errno, flag))
55b38a48 609 warn_on_inaccessible(path);
ba8bd830
JK
610 return ret;
611}
612
4698c8fe 613int access_or_die(const char *path, int mode, unsigned flag)
96b9e0e3
JN
614{
615 int ret = access(path, mode);
4698c8fe 616 if (ret && !access_error_is_ok(errno, flag))
96b9e0e3
JN
617 die_errno(_("unable to access '%s'"), path);
618 return ret;
619}
620
2f705875
JK
621struct passwd *xgetpwuid_self(void)
622{
623 struct passwd *pw;
624
625 errno = 0;
626 pw = getpwuid(getuid());
627 if (!pw)
628 die(_("unable to look up current user in the passwd file: %s"),
629 errno ? strerror(errno) : _("no such user"));
630 return pw;
631}
aa14e980
RS
632
633char *xgetcwd(void)
634{
635 struct strbuf sb = STRBUF_INIT;
636 if (strbuf_getcwd(&sb))
637 die_errno(_("unable to get current working directory"));
638 return strbuf_detach(&sb, NULL);
639}
316e53e6 640
7b03c89e
JK
641int xsnprintf(char *dst, size_t max, const char *fmt, ...)
642{
643 va_list ap;
644 int len;
645
646 va_start(ap, fmt);
647 len = vsnprintf(dst, max, fmt, ap);
648 va_end(ap);
649
650 if (len < 0)
651 die("BUG: your snprintf is broken");
652 if (len >= max)
653 die("BUG: attempt to snprintf into too-small buffer");
654 return len;
655}
656
12d6ce1d
JH
657static int write_file_v(const char *path, int fatal,
658 const char *fmt, va_list params)
316e53e6
NTND
659{
660 struct strbuf sb = STRBUF_INIT;
316e53e6
NTND
661 int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666);
662 if (fd < 0) {
663 if (fatal)
664 die_errno(_("could not open %s for writing"), path);
665 return -1;
666 }
316e53e6 667 strbuf_vaddf(&sb, fmt, params);
e7ffa38c 668 strbuf_complete_line(&sb);
316e53e6
NTND
669 if (write_in_full(fd, sb.buf, sb.len) != sb.len) {
670 int err = errno;
671 close(fd);
672 strbuf_release(&sb);
673 errno = err;
674 if (fatal)
675 die_errno(_("could not write to %s"), path);
676 return -1;
677 }
678 strbuf_release(&sb);
679 if (close(fd)) {
680 if (fatal)
681 die_errno(_("could not close %s"), path);
682 return -1;
683 }
684 return 0;
685}
2024d317 686
12d6ce1d
JH
687int write_file(const char *path, const char *fmt, ...)
688{
689 int status;
690 va_list params;
691
692 va_start(params, fmt);
693 status = write_file_v(path, 1, fmt, params);
694 va_end(params);
695 return status;
696}
697
698int write_file_gently(const char *path, const char *fmt, ...)
699{
700 int status;
701 va_list params;
702
703 va_start(params, fmt);
704 status = write_file_v(path, 0, fmt, params);
705 va_end(params);
706 return status;
707}
708
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JS
709void sleep_millisec(int millisec)
710{
711 poll(NULL, 0, millisec);
712}