freshlybakedca.ke
Git fork
1/*
2 * Various trivial helper wrappers around standard functions
3 */
4
5#define DISABLE_SIGN_COMPARE_WARNINGS
6
7#include "git-compat-util.h"
8#include "abspath.h"
9#include "parse.h"
10#include "gettext.h"
11#include "strbuf.h"
12#include "trace2.h"
13
14#ifdef HAVE_RTLGENRANDOM
15/* This is required to get access to RtlGenRandom. */
16#define SystemFunction036 NTAPI SystemFunction036
17#include <ntsecapi.h>
18#undef SystemFunction036
19#endif
20
21static int memory_limit_check(size_t size, int gentle)
22{
23 static size_t limit = 0;
24 if (!limit) {
25 limit = git_env_ulong("GIT_ALLOC_LIMIT", 0);
26 if (!limit)
27 limit = SIZE_MAX;
28 }
29 if (size > limit) {
30 if (gentle) {
31 error("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
32 (uintmax_t)size, (uintmax_t)limit);
33 return -1;
34 } else
35 die("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
36 (uintmax_t)size, (uintmax_t)limit);
37 }
38 return 0;
39}
40
41char *xstrdup(const char *str)
42{
43 char *ret = strdup(str);
44 if (!ret)
45 die("Out of memory, strdup failed");
46 return ret;
47}
48
49static void *do_xmalloc(size_t size, int gentle)
50{
51 void *ret;
52
53 if (memory_limit_check(size, gentle))
54 return NULL;
55 ret = malloc(size);
56 if (!ret && !size)
57 ret = malloc(1);
58 if (!ret) {
59 if (!gentle)
60 die("Out of memory, malloc failed (tried to allocate %lu bytes)",
61 (unsigned long)size);
62 else {
63 error("Out of memory, malloc failed (tried to allocate %lu bytes)",
64 (unsigned long)size);
65 return NULL;
66 }
67 }
68#ifdef XMALLOC_POISON
69 memset(ret, 0xA5, size);
70#endif
71 return ret;
72}
73
74void *xmalloc(size_t size)
75{
76 return do_xmalloc(size, 0);
77}
78
79static void *do_xmallocz(size_t size, int gentle)
80{
81 void *ret;
82 if (unsigned_add_overflows(size, 1)) {
83 if (gentle) {
84 error("Data too large to fit into virtual memory space.");
85 return NULL;
86 } else
87 die("Data too large to fit into virtual memory space.");
88 }
89 ret = do_xmalloc(size + 1, gentle);
90 if (ret)
91 ((char*)ret)[size] = 0;
92 return ret;
93}
94
95void *xmallocz(size_t size)
96{
97 return do_xmallocz(size, 0);
98}
99
100void *xmallocz_gently(size_t size)
101{
102 return do_xmallocz(size, 1);
103}
104
105/*
106 * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
107 * "data" to the allocated memory, zero terminates the allocated memory,
108 * and returns a pointer to the allocated memory. If the allocation fails,
109 * the program dies.
110 */
111void *xmemdupz(const void *data, size_t len)
112{
113 return memcpy(xmallocz(len), data, len);
114}
115
116char *xstrndup(const char *str, size_t len)
117{
118 char *p = memchr(str, '\0', len);
119 return xmemdupz(str, p ? p - str : len);
120}
121
122int xstrncmpz(const char *s, const char *t, size_t len)
123{
124 int res = strncmp(s, t, len);
125 if (res)
126 return res;
127 return s[len] == '\0' ? 0 : 1;
128}
129
130void *xrealloc(void *ptr, size_t size)
131{
132 void *ret;
133
134 if (!size) {
135 free(ptr);
136 return xmalloc(0);
137 }
138
139 memory_limit_check(size, 0);
140 ret = realloc(ptr, size);
141 if (!ret)
142 die("Out of memory, realloc failed");
143 return ret;
144}
145
146void *xcalloc(size_t nmemb, size_t size)
147{
148 void *ret;
149
150 if (unsigned_mult_overflows(nmemb, size))
151 die("data too large to fit into virtual memory space");
152
153 memory_limit_check(size * nmemb, 0);
154 ret = calloc(nmemb, size);
155 if (!ret && (!nmemb || !size))
156 ret = calloc(1, 1);
157 if (!ret)
158 die("Out of memory, calloc failed");
159 return ret;
160}
161
162void xsetenv(const char *name, const char *value, int overwrite)
163{
164 if (setenv(name, value, overwrite))
165 die_errno(_("could not setenv '%s'"), name ? name : "(null)");
166}
167
168/**
169 * xopen() is the same as open(), but it die()s if the open() fails.
170 */
171int xopen(const char *path, int oflag, ...)
172{
173 mode_t mode = 0;
174 va_list ap;
175
176 /*
177 * va_arg() will have undefined behavior if the specified type is not
178 * compatible with the argument type. Since integers are promoted to
179 * ints, we fetch the next argument as an int, and then cast it to a
180 * mode_t to avoid undefined behavior.
181 */
182 va_start(ap, oflag);
183 if (oflag & O_CREAT)
184 mode = va_arg(ap, int);
185 va_end(ap);
186
187 for (;;) {
188 int fd = open(path, oflag, mode);
189 if (fd >= 0)
190 return fd;
191 if (errno == EINTR)
192 continue;
193
194 if ((oflag & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
195 die_errno(_("unable to create '%s'"), path);
196 else if ((oflag & O_RDWR) == O_RDWR)
197 die_errno(_("could not open '%s' for reading and writing"), path);
198 else if ((oflag & O_WRONLY) == O_WRONLY)
199 die_errno(_("could not open '%s' for writing"), path);
200 else
201 die_errno(_("could not open '%s' for reading"), path);
202 }
203}
204
205static int handle_nonblock(int fd, short poll_events, int err)
206{
207 struct pollfd pfd;
208
209 if (err != EAGAIN && err != EWOULDBLOCK)
210 return 0;
211
212 pfd.fd = fd;
213 pfd.events = poll_events;
214
215 /*
216 * no need to check for errors, here;
217 * a subsequent read/write will detect unrecoverable errors
218 */
219 poll(&pfd, 1, -1);
220 return 1;
221}
222
223/*
224 * xread() is the same a read(), but it automatically restarts read()
225 * operations with a recoverable error (EAGAIN and EINTR). xread()
226 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
227 */
228ssize_t xread(int fd, void *buf, size_t len)
229{
230 ssize_t nr;
231 if (len > MAX_IO_SIZE)
232 len = MAX_IO_SIZE;
233 while (1) {
234 nr = read(fd, buf, len);
235 if (nr < 0) {
236 if (errno == EINTR)
237 continue;
238 if (handle_nonblock(fd, POLLIN, errno))
239 continue;
240 }
241 return nr;
242 }
243}
244
245/*
246 * xwrite() is the same a write(), but it automatically restarts write()
247 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
248 * GUARANTEE that "len" bytes is written even if the operation is successful.
249 */
250ssize_t xwrite(int fd, const 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 = write(fd, buf, len);
257 if (nr < 0) {
258 if (errno == EINTR)
259 continue;
260 if (handle_nonblock(fd, POLLOUT, errno))
261 continue;
262 }
263
264 return nr;
265 }
266}
267
268/*
269 * xpread() is the same as pread(), but it automatically restarts pread()
270 * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
271 * NOT GUARANTEE that "len" bytes is read even if the data is available.
272 */
273ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
274{
275 ssize_t nr;
276 if (len > MAX_IO_SIZE)
277 len = MAX_IO_SIZE;
278 while (1) {
279 nr = pread(fd, buf, len, offset);
280 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
281 continue;
282 return nr;
283 }
284}
285
286ssize_t read_in_full(int fd, void *buf, size_t count)
287{
288 char *p = buf;
289 ssize_t total = 0;
290
291 while (count > 0) {
292 ssize_t loaded = xread(fd, p, count);
293 if (loaded < 0)
294 return -1;
295 if (loaded == 0)
296 return total;
297 count -= loaded;
298 p += loaded;
299 total += loaded;
300 }
301
302 return total;
303}
304
305ssize_t write_in_full(int fd, const void *buf, size_t count)
306{
307 const char *p = buf;
308 ssize_t total = 0;
309
310 while (count > 0) {
311 ssize_t written = xwrite(fd, p, count);
312 if (written < 0)
313 return -1;
314 if (!written) {
315 errno = ENOSPC;
316 return -1;
317 }
318 count -= written;
319 p += written;
320 total += written;
321 }
322
323 return total;
324}
325
326ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
327{
328 char *p = buf;
329 ssize_t total = 0;
330
331 while (count > 0) {
332 ssize_t loaded = xpread(fd, p, count, offset);
333 if (loaded < 0)
334 return -1;
335 if (loaded == 0)
336 return total;
337 count -= loaded;
338 p += loaded;
339 total += loaded;
340 offset += loaded;
341 }
342
343 return total;
344}
345
346int xdup(int fd)
347{
348 int ret = dup(fd);
349 if (ret < 0)
350 die_errno("dup failed");
351 return ret;
352}
353
354/**
355 * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
356 */
357FILE *xfopen(const char *path, const char *mode)
358{
359 for (;;) {
360 FILE *fp = fopen(path, mode);
361 if (fp)
362 return fp;
363 if (errno == EINTR)
364 continue;
365
366 if (*mode && mode[1] == '+')
367 die_errno(_("could not open '%s' for reading and writing"), path);
368 else if (*mode == 'w' || *mode == 'a')
369 die_errno(_("could not open '%s' for writing"), path);
370 else
371 die_errno(_("could not open '%s' for reading"), path);
372 }
373}
374
375FILE *xfdopen(int fd, const char *mode)
376{
377 FILE *stream = fdopen(fd, mode);
378 if (!stream)
379 die_errno("Out of memory? fdopen failed");
380 return stream;
381}
382
383FILE *fopen_for_writing(const char *path)
384{
385 FILE *ret = fopen(path, "w");
386
387 if (!ret && errno == EPERM) {
388 if (!unlink(path))
389 ret = fopen(path, "w");
390 else
391 errno = EPERM;
392 }
393 return ret;
394}
395
396static void warn_on_inaccessible(const char *path)
397{
398 warning_errno(_("unable to access '%s'"), path);
399}
400
401int warn_on_fopen_errors(const char *path)
402{
403 if (errno != ENOENT && errno != ENOTDIR) {
404 warn_on_inaccessible(path);
405 return -1;
406 }
407
408 return 0;
409}
410
411FILE *fopen_or_warn(const char *path, const char *mode)
412{
413 FILE *fp = fopen(path, mode);
414
415 if (fp)
416 return fp;
417
418 warn_on_fopen_errors(path);
419 return NULL;
420}
421
422int xmkstemp(char *filename_template)
423{
424 int fd;
425 char origtemplate[PATH_MAX];
426 strlcpy(origtemplate, filename_template, sizeof(origtemplate));
427
428 fd = mkstemp(filename_template);
429 if (fd < 0) {
430 int saved_errno = errno;
431 const char *nonrelative_template;
432
433 if (strlen(filename_template) != strlen(origtemplate))
434 filename_template = origtemplate;
435
436 nonrelative_template = absolute_path(filename_template);
437 errno = saved_errno;
438 die_errno("Unable to create temporary file '%s'",
439 nonrelative_template);
440 }
441 return fd;
442}
443
444/* Adapted from libiberty's mkstemp.c. */
445
446#undef TMP_MAX
447#define TMP_MAX 16384
448
449int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
450{
451 static const char letters[] =
452 "abcdefghijklmnopqrstuvwxyz"
453 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
454 "0123456789";
455 static const int num_letters = ARRAY_SIZE(letters) - 1;
456 static const char x_pattern[] = "XXXXXX";
457 static const int num_x = ARRAY_SIZE(x_pattern) - 1;
458 char *filename_template;
459 size_t len;
460 int fd, count;
461
462 len = strlen(pattern);
463
464 if (len < num_x + suffix_len) {
465 errno = EINVAL;
466 return -1;
467 }
468
469 if (strncmp(&pattern[len - num_x - suffix_len], x_pattern, num_x)) {
470 errno = EINVAL;
471 return -1;
472 }
473
474 /*
475 * Replace pattern's XXXXXX characters with randomness.
476 * Try TMP_MAX different filenames.
477 */
478 filename_template = &pattern[len - num_x - suffix_len];
479 for (count = 0; count < TMP_MAX; ++count) {
480 int i;
481 uint64_t v;
482 if (csprng_bytes(&v, sizeof(v), 0) < 0)
483 return error_errno("unable to get random bytes for temporary file");
484
485 /* Fill in the random bits. */
486 for (i = 0; i < num_x; i++) {
487 filename_template[i] = letters[v % num_letters];
488 v /= num_letters;
489 }
490
491 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
492 if (fd >= 0)
493 return fd;
494 /*
495 * Fatal error (EPERM, ENOSPC etc).
496 * It doesn't make sense to loop.
497 */
498 if (errno != EEXIST)
499 break;
500 }
501 /* We return the null string if we can't find a unique file name. */
502 pattern[0] = '\0';
503 return -1;
504}
505
506int git_mkstemp_mode(char *pattern, int mode)
507{
508 /* mkstemp is just mkstemps with no suffix */
509 return git_mkstemps_mode(pattern, 0, mode);
510}
511
512int xmkstemp_mode(char *filename_template, int mode)
513{
514 int fd;
515 char origtemplate[PATH_MAX];
516 strlcpy(origtemplate, filename_template, sizeof(origtemplate));
517
518 fd = git_mkstemp_mode(filename_template, mode);
519 if (fd < 0) {
520 int saved_errno = errno;
521 const char *nonrelative_template;
522
523 if (!filename_template[0])
524 filename_template = origtemplate;
525
526 nonrelative_template = absolute_path(filename_template);
527 errno = saved_errno;
528 die_errno("Unable to create temporary file '%s'",
529 nonrelative_template);
530 }
531 return fd;
532}
533
534/*
535 * Some platforms return EINTR from fsync. Since fsync is invoked in some
536 * cases by a wrapper that dies on failure, do not expose EINTR to callers.
537 */
538static int fsync_loop(int fd)
539{
540 int err;
541
542 do {
543 err = fsync(fd);
544 } while (err < 0 && errno == EINTR);
545 return err;
546}
547
548int git_fsync(int fd, enum fsync_action action)
549{
550 switch (action) {
551 case FSYNC_WRITEOUT_ONLY:
552 trace2_counter_add(TRACE2_COUNTER_ID_FSYNC_WRITEOUT_ONLY, 1);
553
554#ifdef __APPLE__
555 /*
556 * On macOS, fsync just causes filesystem cache writeback but
557 * does not flush hardware caches.
558 */
559 return fsync_loop(fd);
560#endif
561
562#ifdef HAVE_SYNC_FILE_RANGE
563 /*
564 * On linux 2.6.17 and above, sync_file_range is the way to
565 * issue a writeback without a hardware flush. An offset of
566 * 0 and size of 0 indicates writeout of the entire file and the
567 * wait flags ensure that all dirty data is written to the disk
568 * (potentially in a disk-side cache) before we continue.
569 */
570
571 return sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WAIT_BEFORE |
572 SYNC_FILE_RANGE_WRITE |
573 SYNC_FILE_RANGE_WAIT_AFTER);
574#endif
575
576#ifdef fsync_no_flush
577 return fsync_no_flush(fd);
578#endif
579
580 errno = ENOSYS;
581 return -1;
582
583 case FSYNC_HARDWARE_FLUSH:
584 trace2_counter_add(TRACE2_COUNTER_ID_FSYNC_HARDWARE_FLUSH, 1);
585
586 /*
587 * On macOS, a special fcntl is required to really flush the
588 * caches within the storage controller. As of this writing,
589 * this is a very expensive operation on Apple SSDs.
590 */
591#ifdef __APPLE__
592 return fcntl(fd, F_FULLFSYNC);
593#else
594 return fsync_loop(fd);
595#endif
596 default:
597 BUG("unexpected git_fsync(%d) call", action);
598 }
599}
600
601static int warn_if_unremovable(const char *op, const char *file, int rc)
602{
603 int err;
604 if (!rc || errno == ENOENT)
605 return 0;
606 err = errno;
607 warning_errno("unable to %s '%s'", op, file);
608 errno = err;
609 return rc;
610}
611
612int unlink_or_msg(const char *file, struct strbuf *err)
613{
614 int rc = unlink(file);
615
616 assert(err);
617
618 if (!rc || errno == ENOENT)
619 return 0;
620
621 strbuf_addf(err, "unable to unlink '%s': %s",
622 file, strerror(errno));
623 return -1;
624}
625
626int unlink_or_warn(const char *file)
627{
628 return warn_if_unremovable("unlink", file, unlink(file));
629}
630
631int rmdir_or_warn(const char *file)
632{
633 return warn_if_unremovable("rmdir", file, rmdir(file));
634}
635
636static int access_error_is_ok(int err, unsigned flag)
637{
638 return (is_missing_file_error(err) ||
639 ((flag & ACCESS_EACCES_OK) && err == EACCES));
640}
641
642int access_or_warn(const char *path, int mode, unsigned flag)
643{
644 int ret = access(path, mode);
645 if (ret && !access_error_is_ok(errno, flag))
646 warn_on_inaccessible(path);
647 return ret;
648}
649
650int access_or_die(const char *path, int mode, unsigned flag)
651{
652 int ret = access(path, mode);
653 if (ret && !access_error_is_ok(errno, flag))
654 die_errno(_("unable to access '%s'"), path);
655 return ret;
656}
657
658char *xgetcwd(void)
659{
660 struct strbuf sb = STRBUF_INIT;
661 if (strbuf_getcwd(&sb))
662 die_errno(_("unable to get current working directory"));
663 return strbuf_detach(&sb, NULL);
664}
665
666int xsnprintf(char *dst, size_t max, const char *fmt, ...)
667{
668 va_list ap;
669 int len;
670
671 va_start(ap, fmt);
672 len = vsnprintf(dst, max, fmt, ap);
673 va_end(ap);
674
675 if (len < 0)
676 die(_("unable to format message: %s"), fmt);
677 if (len >= max)
678 BUG("attempt to snprintf into too-small buffer");
679 return len;
680}
681
682void write_file_buf(const char *path, const char *buf, size_t len)
683{
684 int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
685 if (write_in_full(fd, buf, len) < 0)
686 die_errno(_("could not write to '%s'"), path);
687 if (close(fd))
688 die_errno(_("could not close '%s'"), path);
689}
690
691void write_file(const char *path, const char *fmt, ...)
692{
693 va_list params;
694 struct strbuf sb = STRBUF_INIT;
695
696 va_start(params, fmt);
697 strbuf_vaddf(&sb, fmt, params);
698 va_end(params);
699
700 strbuf_complete_line(&sb);
701
702 write_file_buf(path, sb.buf, sb.len);
703 strbuf_release(&sb);
704}
705
706void sleep_millisec(int millisec)
707{
708 poll(NULL, 0, millisec);
709}
710
711int xgethostname(char *buf, size_t len)
712{
713 /*
714 * If the full hostname doesn't fit in buf, POSIX does not
715 * specify whether the buffer will be null-terminated, so to
716 * be safe, do it ourselves.
717 */
718 int ret = gethostname(buf, len);
719 if (!ret)
720 buf[len - 1] = 0;
721 return ret;
722}
723
724int is_missing_file(const char *filename)
725{
726 struct stat st;
727
728 if (stat(filename, &st) < 0) {
729 if (errno == ENOENT)
730 return 1;
731 die_errno(_("could not stat %s"), filename);
732 }
733
734 return 0;
735}
736
737int is_empty_or_missing_file(const char *filename)
738{
739 struct stat st;
740
741 if (stat(filename, &st) < 0) {
742 if (errno == ENOENT)
743 return 1;
744 die_errno(_("could not stat %s"), filename);
745 }
746
747 return !st.st_size;
748}
749
750int open_nofollow(const char *path, int flags)
751{
752#ifdef O_NOFOLLOW
753 int ret = open(path, flags | O_NOFOLLOW);
754 /*
755 * NetBSD sets errno to EFTYPE when path is a symlink. The only other
756 * time this errno occurs when O_REGULAR is used. Since we don't use
757 * it anywhere we can avoid an lstat here. FreeBSD does the same with
758 * EMLINK.
759 */
760# ifdef __NetBSD__
761# define SYMLINK_ERRNO EFTYPE
762# elif defined(__FreeBSD__)
763# define SYMLINK_ERRNO EMLINK
764# endif
765# if SYMLINK_ERRNO
766 if (ret < 0 && errno == SYMLINK_ERRNO) {
767 errno = ELOOP;
768 return -1;
769 }
770# undef SYMLINK_ERRNO
771# endif
772 return ret;
773#else
774 struct stat st;
775 if (lstat(path, &st) < 0)
776 return -1;
777 if (S_ISLNK(st.st_mode)) {
778 errno = ELOOP;
779 return -1;
780 }
781 return open(path, flags);
782#endif
783}
784
785int csprng_bytes(void *buf, size_t len, MAYBE_UNUSED unsigned flags)
786{
787#if defined(HAVE_ARC4RANDOM) || defined(HAVE_ARC4RANDOM_LIBBSD)
788 /* This function never returns an error. */
789 arc4random_buf(buf, len);
790 return 0;
791#elif defined(HAVE_GETRANDOM)
792 ssize_t res;
793 char *p = buf;
794 while (len) {
795 res = getrandom(p, len, 0);
796 if (res < 0)
797 return -1;
798 len -= res;
799 p += res;
800 }
801 return 0;
802#elif defined(HAVE_GETENTROPY)
803 int res;
804 char *p = buf;
805 while (len) {
806 /* getentropy has a maximum size of 256 bytes. */
807 size_t chunk = len < 256 ? len : 256;
808 res = getentropy(p, chunk);
809 if (res < 0)
810 return -1;
811 len -= chunk;
812 p += chunk;
813 }
814 return 0;
815#elif defined(HAVE_RTLGENRANDOM)
816 if (!RtlGenRandom(buf, len))
817 return -1;
818 return 0;
819#elif defined(HAVE_OPENSSL_CSPRNG)
820 switch (RAND_pseudo_bytes(buf, len)) {
821 case 1:
822 return 0;
823 case 0:
824 if (flags & CSPRNG_BYTES_INSECURE)
825 return 0;
826 errno = EIO;
827 return -1;
828 default:
829 errno = ENOTSUP;
830 return -1;
831 }
832#else
833 ssize_t res;
834 char *p = buf;
835 int fd, err;
836 fd = open("/dev/urandom", O_RDONLY);
837 if (fd < 0)
838 return -1;
839 while (len) {
840 res = xread(fd, p, len);
841 if (res < 0) {
842 err = errno;
843 close(fd);
844 errno = err;
845 return -1;
846 }
847 len -= res;
848 p += res;
849 }
850 close(fd);
851 return 0;
852#endif
853}
854
855uint32_t git_rand(unsigned flags)
856{
857 uint32_t result;
858
859 if (csprng_bytes(&result, sizeof(result), flags) < 0)
860 die(_("unable to get random bytes"));
861
862 return result;
863}
864
865static void mmap_limit_check(size_t length)
866{
867 static size_t limit = 0;
868 if (!limit) {
869 limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
870 if (!limit)
871 limit = SIZE_MAX;
872 }
873 if (length > limit)
874 die(_("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX),
875 (uintmax_t)length, (uintmax_t)limit);
876}
877
878void *xmmap_gently(void *start, size_t length,
879 int prot, int flags, int fd, off_t offset)
880{
881 void *ret;
882
883 mmap_limit_check(length);
884 ret = mmap(start, length, prot, flags, fd, offset);
885 if (ret == MAP_FAILED && !length)
886 ret = NULL;
887 return ret;
888}
889
890const char *mmap_os_err(void)
891{
892 static const char blank[] = "";
893#if defined(__linux__)
894 if (errno == ENOMEM) {
895 /* this continues an existing error message: */
896 static const char enomem[] =
897", check sys.vm.max_map_count and/or RLIMIT_DATA";
898 return enomem;
899 }
900#endif /* OS-specific bits */
901 return blank;
902}
903
904void *xmmap(void *start, size_t length,
905 int prot, int flags, int fd, off_t offset)
906{
907 void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
908 if (ret == MAP_FAILED)
909 die_errno(_("mmap failed%s"), mmap_os_err());
910 return ret;
911}