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[git.git] / wrapper.c
blobd20356a776bc63d4a94e4b421582433fb915087a
1 /*
2 * Various trivial helper wrappers around standard functions
3 */
4 #include "cache.h"
5 #include "config.h"
7 static void do_nothing(size_t size)
11 static void (*try_to_free_routine)(size_t size) = do_nothing;
13 static int memory_limit_check(size_t size, int gentle)
15 static size_t limit = 0;
16 if (!limit) {
17 limit = git_env_ulong("GIT_ALLOC_LIMIT", 0);
18 if (!limit)
19 limit = SIZE_MAX;
21 if (size > limit) {
22 if (gentle) {
23 error("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
24 (uintmax_t)size, (uintmax_t)limit);
25 return -1;
26 } else
27 die("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
28 (uintmax_t)size, (uintmax_t)limit);
30 return 0;
33 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
35 try_to_free_t old = try_to_free_routine;
36 if (!routine)
37 routine = do_nothing;
38 try_to_free_routine = routine;
39 return old;
42 char *xstrdup(const char *str)
44 char *ret = strdup(str);
45 if (!ret) {
46 try_to_free_routine(strlen(str) + 1);
47 ret = strdup(str);
48 if (!ret)
49 die("Out of memory, strdup failed");
51 return ret;
54 static void *do_xmalloc(size_t size, int gentle)
56 void *ret;
58 if (memory_limit_check(size, gentle))
59 return NULL;
60 ret = malloc(size);
61 if (!ret && !size)
62 ret = malloc(1);
63 if (!ret) {
64 try_to_free_routine(size);
65 ret = malloc(size);
66 if (!ret && !size)
67 ret = malloc(1);
68 if (!ret) {
69 if (!gentle)
70 die("Out of memory, malloc failed (tried to allocate %lu bytes)",
71 (unsigned long)size);
72 else {
73 error("Out of memory, malloc failed (tried to allocate %lu bytes)",
74 (unsigned long)size);
75 return NULL;
79 #ifdef XMALLOC_POISON
80 memset(ret, 0xA5, size);
81 #endif
82 return ret;
85 void *xmalloc(size_t size)
87 return do_xmalloc(size, 0);
90 static void *do_xmallocz(size_t size, int gentle)
92 void *ret;
93 if (unsigned_add_overflows(size, 1)) {
94 if (gentle) {
95 error("Data too large to fit into virtual memory space.");
96 return NULL;
97 } else
98 die("Data too large to fit into virtual memory space.");
100 ret = do_xmalloc(size + 1, gentle);
101 if (ret)
102 ((char*)ret)[size] = 0;
103 return ret;
106 void *xmallocz(size_t size)
108 return do_xmallocz(size, 0);
111 void *xmallocz_gently(size_t size)
113 return do_xmallocz(size, 1);
117 * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
118 * "data" to the allocated memory, zero terminates the allocated memory,
119 * and returns a pointer to the allocated memory. If the allocation fails,
120 * the program dies.
122 void *xmemdupz(const void *data, size_t len)
124 return memcpy(xmallocz(len), data, len);
127 char *xstrndup(const char *str, size_t len)
129 char *p = memchr(str, '\0', len);
130 return xmemdupz(str, p ? p - str : len);
133 void *xrealloc(void *ptr, size_t size)
135 void *ret;
137 memory_limit_check(size, 0);
138 ret = realloc(ptr, size);
139 if (!ret && !size)
140 ret = realloc(ptr, 1);
141 if (!ret) {
142 try_to_free_routine(size);
143 ret = realloc(ptr, size);
144 if (!ret && !size)
145 ret = realloc(ptr, 1);
146 if (!ret)
147 die("Out of memory, realloc failed");
149 return ret;
152 void *xcalloc(size_t nmemb, size_t size)
154 void *ret;
156 if (unsigned_mult_overflows(nmemb, size))
157 die("data too large to fit into virtual memory space");
159 memory_limit_check(size * nmemb, 0);
160 ret = calloc(nmemb, size);
161 if (!ret && (!nmemb || !size))
162 ret = calloc(1, 1);
163 if (!ret) {
164 try_to_free_routine(nmemb * size);
165 ret = calloc(nmemb, size);
166 if (!ret && (!nmemb || !size))
167 ret = calloc(1, 1);
168 if (!ret)
169 die("Out of memory, calloc failed");
171 return ret;
175 * Limit size of IO chunks, because huge chunks only cause pain. OS X
176 * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
177 * the absence of bugs, large chunks can result in bad latencies when
178 * you decide to kill the process.
180 * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
181 * that is smaller than that, clip it to SSIZE_MAX, as a call to
182 * read(2) or write(2) larger than that is allowed to fail. As the last
183 * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
184 * to override this, if the definition of SSIZE_MAX given by the platform
185 * is broken.
187 #ifndef MAX_IO_SIZE
188 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
189 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
190 # define MAX_IO_SIZE SSIZE_MAX
191 # else
192 # define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
193 # endif
194 #endif
197 * xopen() is the same as open(), but it die()s if the open() fails.
199 int xopen(const char *path, int oflag, ...)
201 mode_t mode = 0;
202 va_list ap;
205 * va_arg() will have undefined behavior if the specified type is not
206 * compatible with the argument type. Since integers are promoted to
207 * ints, we fetch the next argument as an int, and then cast it to a
208 * mode_t to avoid undefined behavior.
210 va_start(ap, oflag);
211 if (oflag & O_CREAT)
212 mode = va_arg(ap, int);
213 va_end(ap);
215 for (;;) {
216 int fd = open(path, oflag, mode);
217 if (fd >= 0)
218 return fd;
219 if (errno == EINTR)
220 continue;
222 if ((oflag & O_RDWR) == O_RDWR)
223 die_errno(_("could not open '%s' for reading and writing"), path);
224 else if ((oflag & O_WRONLY) == O_WRONLY)
225 die_errno(_("could not open '%s' for writing"), path);
226 else
227 die_errno(_("could not open '%s' for reading"), path);
231 static int handle_nonblock(int fd, short poll_events, int err)
233 struct pollfd pfd;
235 if (err != EAGAIN && err != EWOULDBLOCK)
236 return 0;
238 pfd.fd = fd;
239 pfd.events = poll_events;
242 * no need to check for errors, here;
243 * a subsequent read/write will detect unrecoverable errors
245 poll(&pfd, 1, -1);
246 return 1;
250 * xread() is the same a read(), but it automatically restarts read()
251 * operations with a recoverable error (EAGAIN and EINTR). xread()
252 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
254 ssize_t xread(int fd, void *buf, size_t len)
256 ssize_t nr;
257 if (len > MAX_IO_SIZE)
258 len = MAX_IO_SIZE;
259 while (1) {
260 nr = read(fd, buf, len);
261 if (nr < 0) {
262 if (errno == EINTR)
263 continue;
264 if (handle_nonblock(fd, POLLIN, errno))
265 continue;
267 return nr;
272 * xwrite() is the same a write(), but it automatically restarts write()
273 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
274 * GUARANTEE that "len" bytes is written even if the operation is successful.
276 ssize_t xwrite(int fd, const void *buf, size_t len)
278 ssize_t nr;
279 if (len > MAX_IO_SIZE)
280 len = MAX_IO_SIZE;
281 while (1) {
282 nr = write(fd, buf, len);
283 if (nr < 0) {
284 if (errno == EINTR)
285 continue;
286 if (handle_nonblock(fd, POLLOUT, errno))
287 continue;
290 return nr;
295 * xpread() is the same as pread(), but it automatically restarts pread()
296 * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
297 * NOT GUARANTEE that "len" bytes is read even if the data is available.
299 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
301 ssize_t nr;
302 if (len > MAX_IO_SIZE)
303 len = MAX_IO_SIZE;
304 while (1) {
305 nr = pread(fd, buf, len, offset);
306 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
307 continue;
308 return nr;
312 ssize_t read_in_full(int fd, void *buf, size_t count)
314 char *p = buf;
315 ssize_t total = 0;
317 while (count > 0) {
318 ssize_t loaded = xread(fd, p, count);
319 if (loaded < 0)
320 return -1;
321 if (loaded == 0)
322 return total;
323 count -= loaded;
324 p += loaded;
325 total += loaded;
328 return total;
331 ssize_t write_in_full(int fd, const void *buf, size_t count)
333 const char *p = buf;
334 ssize_t total = 0;
336 while (count > 0) {
337 ssize_t written = xwrite(fd, p, count);
338 if (written < 0)
339 return -1;
340 if (!written) {
341 errno = ENOSPC;
342 return -1;
344 count -= written;
345 p += written;
346 total += written;
349 return total;
352 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
354 char *p = buf;
355 ssize_t total = 0;
357 while (count > 0) {
358 ssize_t loaded = xpread(fd, p, count, offset);
359 if (loaded < 0)
360 return -1;
361 if (loaded == 0)
362 return total;
363 count -= loaded;
364 p += loaded;
365 total += loaded;
366 offset += loaded;
369 return total;
372 int xdup(int fd)
374 int ret = dup(fd);
375 if (ret < 0)
376 die_errno("dup failed");
377 return ret;
381 * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
383 FILE *xfopen(const char *path, const char *mode)
385 for (;;) {
386 FILE *fp = fopen(path, mode);
387 if (fp)
388 return fp;
389 if (errno == EINTR)
390 continue;
392 if (*mode && mode[1] == '+')
393 die_errno(_("could not open '%s' for reading and writing"), path);
394 else if (*mode == 'w' || *mode == 'a')
395 die_errno(_("could not open '%s' for writing"), path);
396 else
397 die_errno(_("could not open '%s' for reading"), path);
401 FILE *xfdopen(int fd, const char *mode)
403 FILE *stream = fdopen(fd, mode);
404 if (stream == NULL)
405 die_errno("Out of memory? fdopen failed");
406 return stream;
409 FILE *fopen_for_writing(const char *path)
411 FILE *ret = fopen(path, "w");
413 if (!ret && errno == EPERM) {
414 if (!unlink(path))
415 ret = fopen(path, "w");
416 else
417 errno = EPERM;
419 return ret;
422 static void warn_on_inaccessible(const char *path)
424 warning_errno(_("unable to access '%s'"), path);
427 int warn_on_fopen_errors(const char *path)
429 if (errno != ENOENT && errno != ENOTDIR) {
430 warn_on_inaccessible(path);
431 return -1;
434 return 0;
437 FILE *fopen_or_warn(const char *path, const char *mode)
439 FILE *fp = fopen(path, mode);
441 if (fp)
442 return fp;
444 warn_on_fopen_errors(path);
445 return NULL;
448 int xmkstemp(char *template)
450 int fd;
451 char origtemplate[PATH_MAX];
452 strlcpy(origtemplate, template, sizeof(origtemplate));
454 fd = mkstemp(template);
455 if (fd < 0) {
456 int saved_errno = errno;
457 const char *nonrelative_template;
459 if (strlen(template) != strlen(origtemplate))
460 template = origtemplate;
462 nonrelative_template = absolute_path(template);
463 errno = saved_errno;
464 die_errno("Unable to create temporary file '%s'",
465 nonrelative_template);
467 return fd;
470 /* Adapted from libiberty's mkstemp.c. */
472 #undef TMP_MAX
473 #define TMP_MAX 16384
475 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
477 static const char letters[] =
478 "abcdefghijklmnopqrstuvwxyz"
479 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
480 "0123456789";
481 static const int num_letters = 62;
482 uint64_t value;
483 struct timeval tv;
484 char *template;
485 size_t len;
486 int fd, count;
488 len = strlen(pattern);
490 if (len < 6 + suffix_len) {
491 errno = EINVAL;
492 return -1;
495 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
496 errno = EINVAL;
497 return -1;
501 * Replace pattern's XXXXXX characters with randomness.
502 * Try TMP_MAX different filenames.
504 gettimeofday(&tv, NULL);
505 value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
506 template = &pattern[len - 6 - suffix_len];
507 for (count = 0; count < TMP_MAX; ++count) {
508 uint64_t v = value;
509 /* Fill in the random bits. */
510 template[0] = letters[v % num_letters]; v /= num_letters;
511 template[1] = letters[v % num_letters]; v /= num_letters;
512 template[2] = letters[v % num_letters]; v /= num_letters;
513 template[3] = letters[v % num_letters]; v /= num_letters;
514 template[4] = letters[v % num_letters]; v /= num_letters;
515 template[5] = letters[v % num_letters]; v /= num_letters;
517 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
518 if (fd >= 0)
519 return fd;
521 * Fatal error (EPERM, ENOSPC etc).
522 * It doesn't make sense to loop.
524 if (errno != EEXIST)
525 break;
527 * This is a random value. It is only necessary that
528 * the next TMP_MAX values generated by adding 7777 to
529 * VALUE are different with (module 2^32).
531 value += 7777;
533 /* We return the null string if we can't find a unique file name. */
534 pattern[0] = '\0';
535 return -1;
538 int git_mkstemp_mode(char *pattern, int mode)
540 /* mkstemp is just mkstemps with no suffix */
541 return git_mkstemps_mode(pattern, 0, mode);
544 int xmkstemp_mode(char *template, int mode)
546 int fd;
547 char origtemplate[PATH_MAX];
548 strlcpy(origtemplate, template, sizeof(origtemplate));
550 fd = git_mkstemp_mode(template, mode);
551 if (fd < 0) {
552 int saved_errno = errno;
553 const char *nonrelative_template;
555 if (!template[0])
556 template = origtemplate;
558 nonrelative_template = absolute_path(template);
559 errno = saved_errno;
560 die_errno("Unable to create temporary file '%s'",
561 nonrelative_template);
563 return fd;
566 static int warn_if_unremovable(const char *op, const char *file, int rc)
568 int err;
569 if (!rc || errno == ENOENT)
570 return 0;
571 err = errno;
572 warning_errno("unable to %s '%s'", op, file);
573 errno = err;
574 return rc;
577 int unlink_or_msg(const char *file, struct strbuf *err)
579 int rc = unlink(file);
581 assert(err);
583 if (!rc || errno == ENOENT)
584 return 0;
586 strbuf_addf(err, "unable to unlink '%s': %s",
587 file, strerror(errno));
588 return -1;
591 int unlink_or_warn(const char *file)
593 return warn_if_unremovable("unlink", file, unlink(file));
596 int rmdir_or_warn(const char *file)
598 return warn_if_unremovable("rmdir", file, rmdir(file));
601 int remove_or_warn(unsigned int mode, const char *file)
603 return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
606 static int access_error_is_ok(int err, unsigned flag)
608 return (is_missing_file_error(err) ||
609 ((flag & ACCESS_EACCES_OK) && err == EACCES));
612 int access_or_warn(const char *path, int mode, unsigned flag)
614 int ret = access(path, mode);
615 if (ret && !access_error_is_ok(errno, flag))
616 warn_on_inaccessible(path);
617 return ret;
620 int access_or_die(const char *path, int mode, unsigned flag)
622 int ret = access(path, mode);
623 if (ret && !access_error_is_ok(errno, flag))
624 die_errno(_("unable to access '%s'"), path);
625 return ret;
628 char *xgetcwd(void)
630 struct strbuf sb = STRBUF_INIT;
631 if (strbuf_getcwd(&sb))
632 die_errno(_("unable to get current working directory"));
633 return strbuf_detach(&sb, NULL);
636 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
638 va_list ap;
639 int len;
641 va_start(ap, fmt);
642 len = vsnprintf(dst, max, fmt, ap);
643 va_end(ap);
645 if (len < 0)
646 die("BUG: your snprintf is broken");
647 if (len >= max)
648 die("BUG: attempt to snprintf into too-small buffer");
649 return len;
652 void write_file_buf(const char *path, const char *buf, size_t len)
654 int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
655 if (write_in_full(fd, buf, len) < 0)
656 die_errno(_("could not write to '%s'"), path);
657 if (close(fd))
658 die_errno(_("could not close '%s'"), path);
661 void write_file(const char *path, const char *fmt, ...)
663 va_list params;
664 struct strbuf sb = STRBUF_INIT;
666 va_start(params, fmt);
667 strbuf_vaddf(&sb, fmt, params);
668 va_end(params);
670 strbuf_complete_line(&sb);
672 write_file_buf(path, sb.buf, sb.len);
673 strbuf_release(&sb);
676 void sleep_millisec(int millisec)
678 poll(NULL, 0, millisec);
681 int xgethostname(char *buf, size_t len)
684 * If the full hostname doesn't fit in buf, POSIX does not
685 * specify whether the buffer will be null-terminated, so to
686 * be safe, do it ourselves.
688 int ret = gethostname(buf, len);
689 if (!ret)
690 buf[len - 1] = 0;
691 return ret;