1/*
2 * Various trivial helper wrappers around standard functions
3 */
4#include "cache.h"
5
6static void do_nothing(size_t size)
7{
8}
9
10static void (*try_to_free_routine)(size_t size) = do_nothing;
11
12static int memory_limit_check(size_t size, int gentle)
13{
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;
19 }
20 if (size > limit) {
21 if (gentle) {
22 error("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
23 (uintmax_t)size, (uintmax_t)limit);
24 return -1;
25 } else
26 die("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
27 (uintmax_t)size, (uintmax_t)limit);
28 }
29 return 0;
30}
31
32try_to_free_t set_try_to_free_routine(try_to_free_t routine)
33{
34 try_to_free_t old = try_to_free_routine;
35 if (!routine)
36 routine = do_nothing;
37 try_to_free_routine = routine;
38 return old;
39}
40
41char *xstrdup(const char *str)
42{
43 char *ret = strdup(str);
44 if (!ret) {
45 try_to_free_routine(strlen(str) + 1);
46 ret = strdup(str);
47 if (!ret)
48 die("Out of memory, strdup failed");
49 }
50 return ret;
51}
52
53static void *do_xmalloc(size_t size, int gentle)
54{
55 void *ret;
56
57 if (memory_limit_check(size, gentle))
58 return NULL;
59 ret = malloc(size);
60 if (!ret && !size)
61 ret = malloc(1);
62 if (!ret) {
63 try_to_free_routine(size);
64 ret = malloc(size);
65 if (!ret && !size)
66 ret = malloc(1);
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 }
77 }
78#ifdef XMALLOC_POISON
79 memset(ret, 0xA5, size);
80#endif
81 return ret;
82}
83
84void *xmalloc(size_t size)
85{
86 return do_xmalloc(size, 0);
87}
88
89static void *do_xmallocz(size_t size, int gentle)
90{
91 void *ret;
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;
102 return ret;
103}
104
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
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{
123 return memcpy(xmallocz(len), data, len);
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{
134 void *ret;
135
136 memory_limit_check(size, 0);
137 ret = realloc(ptr, size);
138 if (!ret && !size)
139 ret = realloc(ptr, 1);
140 if (!ret) {
141 try_to_free_routine(size);
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{
153 void *ret;
154
155 memory_limit_check(size * nmemb, 0);
156 ret = calloc(nmemb, size);
157 if (!ret && (!nmemb || !size))
158 ret = calloc(1, 1);
159 if (!ret) {
160 try_to_free_routine(nmemb * size);
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
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
173 * the absence of bugs, large chunks can result in bad latencies when
174 * you decide to kill the process.
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.
182 */
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
191
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
227static int handle_nonblock(int fd, short poll_events, int err)
228{
229 struct pollfd pfd;
230
231 if (err != EAGAIN && err != EWOULDBLOCK)
232 return 0;
233
234 pfd.fd = fd;
235 pfd.events = poll_events;
236
237 /*
238 * no need to check for errors, here;
239 * a subsequent read/write will detect unrecoverable errors
240 */
241 poll(&pfd, 1, -1);
242 return 1;
243}
244
245/*
246 * xread() is the same a read(), but it automatically restarts read()
247 * operations with a recoverable error (EAGAIN and EINTR). xread()
248 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
249 */
250ssize_t xread(int fd, void *buf, size_t len)
251{
252 ssize_t nr;
253 if (len > MAX_IO_SIZE)
254 len = MAX_IO_SIZE;
255 while (1) {
256 nr = read(fd, buf, len);
257 if (nr < 0) {
258 if (errno == EINTR)
259 continue;
260 if (handle_nonblock(fd, POLLIN, errno))
261 continue;
262 }
263 return nr;
264 }
265}
266
267/*
268 * xwrite() is the same a write(), but it automatically restarts write()
269 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
270 * GUARANTEE that "len" bytes is written even if the operation is successful.
271 */
272ssize_t xwrite(int fd, const void *buf, size_t len)
273{
274 ssize_t nr;
275 if (len > MAX_IO_SIZE)
276 len = MAX_IO_SIZE;
277 while (1) {
278 nr = write(fd, buf, len);
279 if (nr < 0) {
280 if (errno == EINTR)
281 continue;
282 if (handle_nonblock(fd, POLLOUT, errno))
283 continue;
284 }
285
286 return nr;
287 }
288}
289
290/*
291 * xpread() is the same as pread(), but it automatically restarts pread()
292 * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
293 * NOT GUARANTEE that "len" bytes is read even if the data is available.
294 */
295ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
296{
297 ssize_t nr;
298 if (len > MAX_IO_SIZE)
299 len = MAX_IO_SIZE;
300 while (1) {
301 nr = pread(fd, buf, len, offset);
302 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
303 continue;
304 return nr;
305 }
306}
307
308ssize_t read_in_full(int fd, void *buf, size_t count)
309{
310 char *p = buf;
311 ssize_t total = 0;
312
313 while (count > 0) {
314 ssize_t loaded = xread(fd, p, count);
315 if (loaded < 0)
316 return -1;
317 if (loaded == 0)
318 return total;
319 count -= loaded;
320 p += loaded;
321 total += loaded;
322 }
323
324 return total;
325}
326
327ssize_t write_in_full(int fd, const void *buf, size_t count)
328{
329 const char *p = buf;
330 ssize_t total = 0;
331
332 while (count > 0) {
333 ssize_t written = xwrite(fd, p, count);
334 if (written < 0)
335 return -1;
336 if (!written) {
337 errno = ENOSPC;
338 return -1;
339 }
340 count -= written;
341 p += written;
342 total += written;
343 }
344
345 return total;
346}
347
348ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
349{
350 char *p = buf;
351 ssize_t total = 0;
352
353 while (count > 0) {
354 ssize_t loaded = xpread(fd, p, count, offset);
355 if (loaded < 0)
356 return -1;
357 if (loaded == 0)
358 return total;
359 count -= loaded;
360 p += loaded;
361 total += loaded;
362 offset += loaded;
363 }
364
365 return total;
366}
367
368int xdup(int fd)
369{
370 int ret = dup(fd);
371 if (ret < 0)
372 die_errno("dup failed");
373 return ret;
374}
375
376/**
377 * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
378 */
379FILE *xfopen(const char *path, const char *mode)
380{
381 for (;;) {
382 FILE *fp = fopen(path, mode);
383 if (fp)
384 return fp;
385 if (errno == EINTR)
386 continue;
387
388 if (*mode && mode[1] == '+')
389 die_errno(_("could not open '%s' for reading and writing"), path);
390 else if (*mode == 'w' || *mode == 'a')
391 die_errno(_("could not open '%s' for writing"), path);
392 else
393 die_errno(_("could not open '%s' for reading"), path);
394 }
395}
396
397FILE *xfdopen(int fd, const char *mode)
398{
399 FILE *stream = fdopen(fd, mode);
400 if (stream == NULL)
401 die_errno("Out of memory? fdopen failed");
402 return stream;
403}
404
405int xmkstemp(char *template)
406{
407 int fd;
408 char origtemplate[PATH_MAX];
409 strlcpy(origtemplate, template, sizeof(origtemplate));
410
411 fd = mkstemp(template);
412 if (fd < 0) {
413 int saved_errno = errno;
414 const char *nonrelative_template;
415
416 if (strlen(template) != strlen(origtemplate))
417 template = origtemplate;
418
419 nonrelative_template = absolute_path(template);
420 errno = saved_errno;
421 die_errno("Unable to create temporary file '%s'",
422 nonrelative_template);
423 }
424 return fd;
425}
426
427/* git_mkstemp() - create tmp file honoring TMPDIR variable */
428int git_mkstemp(char *path, size_t len, const char *template)
429{
430 const char *tmp;
431 size_t n;
432
433 tmp = getenv("TMPDIR");
434 if (!tmp)
435 tmp = "/tmp";
436 n = snprintf(path, len, "%s/%s", tmp, template);
437 if (len <= n) {
438 errno = ENAMETOOLONG;
439 return -1;
440 }
441 return mkstemp(path);
442}
443
444/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
445int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
446{
447 const char *tmp;
448 size_t n;
449
450 tmp = getenv("TMPDIR");
451 if (!tmp)
452 tmp = "/tmp";
453 n = snprintf(path, len, "%s/%s", tmp, template);
454 if (len <= n) {
455 errno = ENAMETOOLONG;
456 return -1;
457 }
458 return mkstemps(path, suffix_len);
459}
460
461/* Adapted from libiberty's mkstemp.c. */
462
463#undef TMP_MAX
464#define TMP_MAX 16384
465
466int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
467{
468 static const char letters[] =
469 "abcdefghijklmnopqrstuvwxyz"
470 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
471 "0123456789";
472 static const int num_letters = 62;
473 uint64_t value;
474 struct timeval tv;
475 char *template;
476 size_t len;
477 int fd, count;
478
479 len = strlen(pattern);
480
481 if (len < 6 + suffix_len) {
482 errno = EINVAL;
483 return -1;
484 }
485
486 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
487 errno = EINVAL;
488 return -1;
489 }
490
491 /*
492 * Replace pattern's XXXXXX characters with randomness.
493 * Try TMP_MAX different filenames.
494 */
495 gettimeofday(&tv, NULL);
496 value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
497 template = &pattern[len - 6 - suffix_len];
498 for (count = 0; count < TMP_MAX; ++count) {
499 uint64_t v = value;
500 /* Fill in the random bits. */
501 template[0] = letters[v % num_letters]; v /= num_letters;
502 template[1] = letters[v % num_letters]; v /= num_letters;
503 template[2] = letters[v % num_letters]; v /= num_letters;
504 template[3] = letters[v % num_letters]; v /= num_letters;
505 template[4] = letters[v % num_letters]; v /= num_letters;
506 template[5] = letters[v % num_letters]; v /= num_letters;
507
508 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
509 if (fd >= 0)
510 return fd;
511 /*
512 * Fatal error (EPERM, ENOSPC etc).
513 * It doesn't make sense to loop.
514 */
515 if (errno != EEXIST)
516 break;
517 /*
518 * This is a random value. It is only necessary that
519 * the next TMP_MAX values generated by adding 7777 to
520 * VALUE are different with (module 2^32).
521 */
522 value += 7777;
523 }
524 /* We return the null string if we can't find a unique file name. */
525 pattern[0] = '\0';
526 return -1;
527}
528
529int git_mkstemp_mode(char *pattern, int mode)
530{
531 /* mkstemp is just mkstemps with no suffix */
532 return git_mkstemps_mode(pattern, 0, mode);
533}
534
535#ifdef NO_MKSTEMPS
536int gitmkstemps(char *pattern, int suffix_len)
537{
538 return git_mkstemps_mode(pattern, suffix_len, 0600);
539}
540#endif
541
542int xmkstemp_mode(char *template, int mode)
543{
544 int fd;
545 char origtemplate[PATH_MAX];
546 strlcpy(origtemplate, template, sizeof(origtemplate));
547
548 fd = git_mkstemp_mode(template, mode);
549 if (fd < 0) {
550 int saved_errno = errno;
551 const char *nonrelative_template;
552
553 if (!template[0])
554 template = origtemplate;
555
556 nonrelative_template = absolute_path(template);
557 errno = saved_errno;
558 die_errno("Unable to create temporary file '%s'",
559 nonrelative_template);
560 }
561 return fd;
562}
563
564static int warn_if_unremovable(const char *op, const char *file, int rc)
565{
566 int err;
567 if (!rc || errno == ENOENT)
568 return 0;
569 err = errno;
570 warning("unable to %s %s: %s", op, file, strerror(errno));
571 errno = err;
572 return rc;
573}
574
575int unlink_or_msg(const char *file, struct strbuf *err)
576{
577 int rc = unlink(file);
578
579 assert(err);
580
581 if (!rc || errno == ENOENT)
582 return 0;
583
584 strbuf_addf(err, "unable to unlink %s: %s",
585 file, strerror(errno));
586 return -1;
587}
588
589int unlink_or_warn(const char *file)
590{
591 return warn_if_unremovable("unlink", file, unlink(file));
592}
593
594int rmdir_or_warn(const char *file)
595{
596 return warn_if_unremovable("rmdir", file, rmdir(file));
597}
598
599int remove_or_warn(unsigned int mode, const char *file)
600{
601 return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
602}
603
604void warn_on_inaccessible(const char *path)
605{
606 warning(_("unable to access '%s': %s"), path, strerror(errno));
607}
608
609static int access_error_is_ok(int err, unsigned flag)
610{
611 return err == ENOENT || err == ENOTDIR ||
612 ((flag & ACCESS_EACCES_OK) && err == EACCES);
613}
614
615int access_or_warn(const char *path, int mode, unsigned flag)
616{
617 int ret = access(path, mode);
618 if (ret && !access_error_is_ok(errno, flag))
619 warn_on_inaccessible(path);
620 return ret;
621}
622
623int access_or_die(const char *path, int mode, unsigned flag)
624{
625 int ret = access(path, mode);
626 if (ret && !access_error_is_ok(errno, flag))
627 die_errno(_("unable to access '%s'"), path);
628 return ret;
629}
630
631struct passwd *xgetpwuid_self(void)
632{
633 struct passwd *pw;
634
635 errno = 0;
636 pw = getpwuid(getuid());
637 if (!pw)
638 die(_("unable to look up current user in the passwd file: %s"),
639 errno ? strerror(errno) : _("no such user"));
640 return pw;
641}
642
643char *xgetcwd(void)
644{
645 struct strbuf sb = STRBUF_INIT;
646 if (strbuf_getcwd(&sb))
647 die_errno(_("unable to get current working directory"));
648 return strbuf_detach(&sb, NULL);
649}
650
651int xsnprintf(char *dst, size_t max, const char *fmt, ...)
652{
653 va_list ap;
654 int len;
655
656 va_start(ap, fmt);
657 len = vsnprintf(dst, max, fmt, ap);
658 va_end(ap);
659
660 if (len < 0)
661 die("BUG: your snprintf is broken");
662 if (len >= max)
663 die("BUG: attempt to snprintf into too-small buffer");
664 return len;
665}
666
667static int write_file_v(const char *path, int fatal,
668 const char *fmt, va_list params)
669{
670 struct strbuf sb = STRBUF_INIT;
671 int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666);
672 if (fd < 0) {
673 if (fatal)
674 die_errno(_("could not open %s for writing"), path);
675 return -1;
676 }
677 strbuf_vaddf(&sb, fmt, params);
678 strbuf_complete_line(&sb);
679 if (write_in_full(fd, sb.buf, sb.len) != sb.len) {
680 int err = errno;
681 close(fd);
682 strbuf_release(&sb);
683 errno = err;
684 if (fatal)
685 die_errno(_("could not write to %s"), path);
686 return -1;
687 }
688 strbuf_release(&sb);
689 if (close(fd)) {
690 if (fatal)
691 die_errno(_("could not close %s"), path);
692 return -1;
693 }
694 return 0;
695}
696
697int write_file(const char *path, const char *fmt, ...)
698{
699 int status;
700 va_list params;
701
702 va_start(params, fmt);
703 status = write_file_v(path, 1, fmt, params);
704 va_end(params);
705 return status;
706}
707
708int write_file_gently(const char *path, const char *fmt, ...)
709{
710 int status;
711 va_list params;
712
713 va_start(params, fmt);
714 status = write_file_v(path, 0, fmt, params);
715 va_end(params);
716 return status;
717}
718
719void sleep_millisec(int millisec)
720{
721 poll(NULL, 0, millisec);
722}