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