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