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[git.git] / wrapper.c
blobe7f197996868a614c84537ad96fc672ea901148d
1 /*
2 * Various trivial helper wrappers around standard functions
3 */
4 #include "cache.h"
6 static void do_nothing(size_t size)
10 static void (*try_to_free_routine)(size_t size) = do_nothing;
12 static int memory_limit_check(size_t size, int gentle)
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;
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);
29 return 0;
32 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
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;
41 char *xstrdup(const char *str)
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");
50 return ret;
53 static void *do_xmalloc(size_t size, int gentle)
55 void *ret;
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;
78 #ifdef XMALLOC_POISON
79 memset(ret, 0xA5, size);
80 #endif
81 return ret;
84 void *xmalloc(size_t size)
86 return do_xmalloc(size, 0);
89 static void *do_xmallocz(size_t size, int gentle)
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.");
99 ret = do_xmalloc(size + 1, gentle);
100 if (ret)
101 ((char*)ret)[size] = 0;
102 return ret;
105 void *xmallocz(size_t size)
107 return do_xmallocz(size, 0);
110 void *xmallocz_gently(size_t size)
112 return do_xmallocz(size, 1);
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.
121 void *xmemdupz(const void *data, size_t len)
123 return memcpy(xmallocz(len), data, len);
126 char *xstrndup(const char *str, size_t len)
128 char *p = memchr(str, '\0', len);
129 return xmemdupz(str, p ? p - str : len);
132 void *xrealloc(void *ptr, size_t size)
134 void *ret;
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");
148 return ret;
151 void *xcalloc(size_t nmemb, size_t size)
153 void *ret;
155 if (unsigned_mult_overflows(nmemb, size))
156 die("data too large to fit into virtual memory space");
158 memory_limit_check(size * nmemb, 0);
159 ret = calloc(nmemb, size);
160 if (!ret && (!nmemb || !size))
161 ret = calloc(1, 1);
162 if (!ret) {
163 try_to_free_routine(nmemb * size);
164 ret = calloc(nmemb, size);
165 if (!ret && (!nmemb || !size))
166 ret = calloc(1, 1);
167 if (!ret)
168 die("Out of memory, calloc failed");
170 return ret;
174 * Limit size of IO chunks, because huge chunks only cause pain. OS X
175 * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
176 * the absence of bugs, large chunks can result in bad latencies when
177 * you decide to kill the process.
179 * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
180 * that is smaller than that, clip it to SSIZE_MAX, as a call to
181 * read(2) or write(2) larger than that is allowed to fail. As the last
182 * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
183 * to override this, if the definition of SSIZE_MAX given by the platform
184 * is broken.
186 #ifndef MAX_IO_SIZE
187 # define MAX_IO_SIZE_DEFAULT (8*1024*1024)
188 # if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
189 # define MAX_IO_SIZE SSIZE_MAX
190 # else
191 # define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
192 # endif
193 #endif
196 * xopen() is the same as open(), but it die()s if the open() fails.
198 int xopen(const char *path, int oflag, ...)
200 mode_t mode = 0;
201 va_list ap;
204 * va_arg() will have undefined behavior if the specified type is not
205 * compatible with the argument type. Since integers are promoted to
206 * ints, we fetch the next argument as an int, and then cast it to a
207 * mode_t to avoid undefined behavior.
209 va_start(ap, oflag);
210 if (oflag & O_CREAT)
211 mode = va_arg(ap, int);
212 va_end(ap);
214 for (;;) {
215 int fd = open(path, oflag, mode);
216 if (fd >= 0)
217 return fd;
218 if (errno == EINTR)
219 continue;
221 if ((oflag & O_RDWR) == O_RDWR)
222 die_errno(_("could not open '%s' for reading and writing"), path);
223 else if ((oflag & O_WRONLY) == O_WRONLY)
224 die_errno(_("could not open '%s' for writing"), path);
225 else
226 die_errno(_("could not open '%s' for reading"), path);
230 static int handle_nonblock(int fd, short poll_events, int err)
232 struct pollfd pfd;
234 if (err != EAGAIN && err != EWOULDBLOCK)
235 return 0;
237 pfd.fd = fd;
238 pfd.events = poll_events;
241 * no need to check for errors, here;
242 * a subsequent read/write will detect unrecoverable errors
244 poll(&pfd, 1, -1);
245 return 1;
249 * xread() is the same a read(), but it automatically restarts read()
250 * operations with a recoverable error (EAGAIN and EINTR). xread()
251 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
253 ssize_t xread(int fd, void *buf, size_t len)
255 ssize_t nr;
256 if (len > MAX_IO_SIZE)
257 len = MAX_IO_SIZE;
258 while (1) {
259 nr = read(fd, buf, len);
260 if (nr < 0) {
261 if (errno == EINTR)
262 continue;
263 if (handle_nonblock(fd, POLLIN, errno))
264 continue;
266 return nr;
271 * xwrite() is the same a write(), but it automatically restarts write()
272 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
273 * GUARANTEE that "len" bytes is written even if the operation is successful.
275 ssize_t xwrite(int fd, const void *buf, size_t len)
277 ssize_t nr;
278 if (len > MAX_IO_SIZE)
279 len = MAX_IO_SIZE;
280 while (1) {
281 nr = write(fd, buf, len);
282 if (nr < 0) {
283 if (errno == EINTR)
284 continue;
285 if (handle_nonblock(fd, POLLOUT, errno))
286 continue;
289 return nr;
294 * xpread() is the same as pread(), but it automatically restarts pread()
295 * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
296 * NOT GUARANTEE that "len" bytes is read even if the data is available.
298 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
300 ssize_t nr;
301 if (len > MAX_IO_SIZE)
302 len = MAX_IO_SIZE;
303 while (1) {
304 nr = pread(fd, buf, len, offset);
305 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
306 continue;
307 return nr;
311 ssize_t read_in_full(int fd, void *buf, size_t count)
313 char *p = buf;
314 ssize_t total = 0;
316 while (count > 0) {
317 ssize_t loaded = xread(fd, p, count);
318 if (loaded < 0)
319 return -1;
320 if (loaded == 0)
321 return total;
322 count -= loaded;
323 p += loaded;
324 total += loaded;
327 return total;
330 ssize_t write_in_full(int fd, const void *buf, size_t count)
332 const char *p = buf;
333 ssize_t total = 0;
335 while (count > 0) {
336 ssize_t written = xwrite(fd, p, count);
337 if (written < 0)
338 return -1;
339 if (!written) {
340 errno = ENOSPC;
341 return -1;
343 count -= written;
344 p += written;
345 total += written;
348 return total;
351 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
353 char *p = buf;
354 ssize_t total = 0;
356 while (count > 0) {
357 ssize_t loaded = xpread(fd, p, count, offset);
358 if (loaded < 0)
359 return -1;
360 if (loaded == 0)
361 return total;
362 count -= loaded;
363 p += loaded;
364 total += loaded;
365 offset += loaded;
368 return total;
371 int xdup(int fd)
373 int ret = dup(fd);
374 if (ret < 0)
375 die_errno("dup failed");
376 return ret;
380 * xfopen() is the same as fopen(), but it die()s if the fopen() fails.
382 FILE *xfopen(const char *path, const char *mode)
384 for (;;) {
385 FILE *fp = fopen(path, mode);
386 if (fp)
387 return fp;
388 if (errno == EINTR)
389 continue;
391 if (*mode && mode[1] == '+')
392 die_errno(_("could not open '%s' for reading and writing"), path);
393 else if (*mode == 'w' || *mode == 'a')
394 die_errno(_("could not open '%s' for writing"), path);
395 else
396 die_errno(_("could not open '%s' for reading"), path);
400 FILE *xfdopen(int fd, const char *mode)
402 FILE *stream = fdopen(fd, mode);
403 if (stream == NULL)
404 die_errno("Out of memory? fdopen failed");
405 return stream;
408 FILE *fopen_for_writing(const char *path)
410 FILE *ret = fopen(path, "w");
412 if (!ret && errno == EPERM) {
413 if (!unlink(path))
414 ret = fopen(path, "w");
415 else
416 errno = EPERM;
418 return ret;
421 int xmkstemp(char *template)
423 int fd;
424 char origtemplate[PATH_MAX];
425 strlcpy(origtemplate, template, sizeof(origtemplate));
427 fd = mkstemp(template);
428 if (fd < 0) {
429 int saved_errno = errno;
430 const char *nonrelative_template;
432 if (strlen(template) != strlen(origtemplate))
433 template = origtemplate;
435 nonrelative_template = absolute_path(template);
436 errno = saved_errno;
437 die_errno("Unable to create temporary file '%s'",
438 nonrelative_template);
440 return fd;
443 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
444 int git_mkstemp(char *path, size_t len, const char *template)
446 const char *tmp;
447 size_t n;
449 tmp = getenv("TMPDIR");
450 if (!tmp)
451 tmp = "/tmp";
452 n = snprintf(path, len, "%s/%s", tmp, template);
453 if (len <= n) {
454 errno = ENAMETOOLONG;
455 return -1;
457 return mkstemp(path);
460 /* Adapted from libiberty's mkstemp.c. */
462 #undef TMP_MAX
463 #define TMP_MAX 16384
465 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
467 static const char letters[] =
468 "abcdefghijklmnopqrstuvwxyz"
469 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
470 "0123456789";
471 static const int num_letters = 62;
472 uint64_t value;
473 struct timeval tv;
474 char *template;
475 size_t len;
476 int fd, count;
478 len = strlen(pattern);
480 if (len < 6 + suffix_len) {
481 errno = EINVAL;
482 return -1;
485 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
486 errno = EINVAL;
487 return -1;
491 * Replace pattern's XXXXXX characters with randomness.
492 * Try TMP_MAX different filenames.
494 gettimeofday(&tv, NULL);
495 value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
496 template = &pattern[len - 6 - suffix_len];
497 for (count = 0; count < TMP_MAX; ++count) {
498 uint64_t v = value;
499 /* Fill in the random bits. */
500 template[0] = letters[v % num_letters]; v /= num_letters;
501 template[1] = letters[v % num_letters]; v /= num_letters;
502 template[2] = letters[v % num_letters]; v /= num_letters;
503 template[3] = letters[v % num_letters]; v /= num_letters;
504 template[4] = letters[v % num_letters]; v /= num_letters;
505 template[5] = letters[v % num_letters]; v /= num_letters;
507 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
508 if (fd >= 0)
509 return fd;
511 * Fatal error (EPERM, ENOSPC etc).
512 * It doesn't make sense to loop.
514 if (errno != EEXIST)
515 break;
517 * This is a random value. It is only necessary that
518 * the next TMP_MAX values generated by adding 7777 to
519 * VALUE are different with (module 2^32).
521 value += 7777;
523 /* We return the null string if we can't find a unique file name. */
524 pattern[0] = '\0';
525 return -1;
528 int git_mkstemp_mode(char *pattern, int mode)
530 /* mkstemp is just mkstemps with no suffix */
531 return git_mkstemps_mode(pattern, 0, mode);
534 #ifdef NO_MKSTEMPS
535 int gitmkstemps(char *pattern, int suffix_len)
537 return git_mkstemps_mode(pattern, suffix_len, 0600);
539 #endif
541 int xmkstemp_mode(char *template, int mode)
543 int fd;
544 char origtemplate[PATH_MAX];
545 strlcpy(origtemplate, template, sizeof(origtemplate));
547 fd = git_mkstemp_mode(template, mode);
548 if (fd < 0) {
549 int saved_errno = errno;
550 const char *nonrelative_template;
552 if (!template[0])
553 template = origtemplate;
555 nonrelative_template = absolute_path(template);
556 errno = saved_errno;
557 die_errno("Unable to create temporary file '%s'",
558 nonrelative_template);
560 return fd;
563 static int warn_if_unremovable(const char *op, const char *file, int rc)
565 int err;
566 if (!rc || errno == ENOENT)
567 return 0;
568 err = errno;
569 warning_errno("unable to %s %s", op, file);
570 errno = err;
571 return rc;
574 int unlink_or_msg(const char *file, struct strbuf *err)
576 int rc = unlink(file);
578 assert(err);
580 if (!rc || errno == ENOENT)
581 return 0;
583 strbuf_addf(err, "unable to unlink %s: %s",
584 file, strerror(errno));
585 return -1;
588 int unlink_or_warn(const char *file)
590 return warn_if_unremovable("unlink", file, unlink(file));
593 int rmdir_or_warn(const char *file)
595 return warn_if_unremovable("rmdir", file, rmdir(file));
598 int remove_or_warn(unsigned int mode, const char *file)
600 return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
603 void warn_on_inaccessible(const char *path)
605 warning_errno(_("unable to access '%s'"), path);
608 static int access_error_is_ok(int err, unsigned flag)
610 return err == ENOENT || err == ENOTDIR ||
611 ((flag & ACCESS_EACCES_OK) && err == EACCES);
614 int access_or_warn(const char *path, int mode, unsigned flag)
616 int ret = access(path, mode);
617 if (ret && !access_error_is_ok(errno, flag))
618 warn_on_inaccessible(path);
619 return ret;
622 int access_or_die(const char *path, int mode, unsigned flag)
624 int ret = access(path, mode);
625 if (ret && !access_error_is_ok(errno, flag))
626 die_errno(_("unable to access '%s'"), path);
627 return ret;
630 char *xgetcwd(void)
632 struct strbuf sb = STRBUF_INIT;
633 if (strbuf_getcwd(&sb))
634 die_errno(_("unable to get current working directory"));
635 return strbuf_detach(&sb, NULL);
638 int xsnprintf(char *dst, size_t max, const char *fmt, ...)
640 va_list ap;
641 int len;
643 va_start(ap, fmt);
644 len = vsnprintf(dst, max, fmt, ap);
645 va_end(ap);
647 if (len < 0)
648 die("BUG: your snprintf is broken");
649 if (len >= max)
650 die("BUG: attempt to snprintf into too-small buffer");
651 return len;
654 void write_file_buf(const char *path, const char *buf, size_t len)
656 int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
657 if (write_in_full(fd, buf, len) != len)
658 die_errno(_("could not write to %s"), path);
659 if (close(fd))
660 die_errno(_("could not close %s"), path);
663 void write_file(const char *path, const char *fmt, ...)
665 va_list params;
666 struct strbuf sb = STRBUF_INIT;
668 va_start(params, fmt);
669 strbuf_vaddf(&sb, fmt, params);
670 va_end(params);
672 strbuf_complete_line(&sb);
674 write_file_buf(path, sb.buf, sb.len);
675 strbuf_release(&sb);
678 void sleep_millisec(int millisec)
680 poll(NULL, 0, millisec);