Documentation/describe: improve one-line summary
[git.git] / wrapper.c
blob007ec0d8eac529579cc00b14f9baaddb7ac68487
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 memory_limit_check(size * nmemb, 0);
156 ret = calloc(nmemb, size);
157 if (!ret && (!nmemb || !size))
158 ret = calloc(1, 1);
159 if (!ret) {
160 try_to_free_routine(nmemb * size);
161 ret = calloc(nmemb, size);
162 if (!ret && (!nmemb || !size))
163 ret = calloc(1, 1);
164 if (!ret)
165 die("Out of memory, calloc failed");
167 return ret;
171 * Limit size of IO chunks, because huge chunks only cause pain. OS X
172 * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
173 * the absence of bugs, large chunks can result in bad latencies when
174 * you decide to kill the process.
176 #define MAX_IO_SIZE (8*1024*1024)
179 * xread() is the same a read(), but it automatically restarts read()
180 * operations with a recoverable error (EAGAIN and EINTR). xread()
181 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
183 ssize_t xread(int fd, void *buf, size_t len)
185 ssize_t nr;
186 if (len > MAX_IO_SIZE)
187 len = MAX_IO_SIZE;
188 while (1) {
189 nr = read(fd, buf, len);
190 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
191 continue;
192 return nr;
197 * xwrite() is the same a write(), but it automatically restarts write()
198 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
199 * GUARANTEE that "len" bytes is written even if the operation is successful.
201 ssize_t xwrite(int fd, const void *buf, size_t len)
203 ssize_t nr;
204 if (len > MAX_IO_SIZE)
205 len = MAX_IO_SIZE;
206 while (1) {
207 nr = write(fd, buf, len);
208 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
209 continue;
210 return nr;
215 * xpread() is the same as pread(), but it automatically restarts pread()
216 * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
217 * NOT GUARANTEE that "len" bytes is read even if the data is available.
219 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
221 ssize_t nr;
222 if (len > MAX_IO_SIZE)
223 len = MAX_IO_SIZE;
224 while (1) {
225 nr = pread(fd, buf, len, offset);
226 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
227 continue;
228 return nr;
232 ssize_t read_in_full(int fd, void *buf, size_t count)
234 char *p = buf;
235 ssize_t total = 0;
237 while (count > 0) {
238 ssize_t loaded = xread(fd, p, count);
239 if (loaded < 0)
240 return -1;
241 if (loaded == 0)
242 return total;
243 count -= loaded;
244 p += loaded;
245 total += loaded;
248 return total;
251 ssize_t write_in_full(int fd, const void *buf, size_t count)
253 const char *p = buf;
254 ssize_t total = 0;
256 while (count > 0) {
257 ssize_t written = xwrite(fd, p, count);
258 if (written < 0)
259 return -1;
260 if (!written) {
261 errno = ENOSPC;
262 return -1;
264 count -= written;
265 p += written;
266 total += written;
269 return total;
272 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
274 char *p = buf;
275 ssize_t total = 0;
277 while (count > 0) {
278 ssize_t loaded = xpread(fd, p, count, offset);
279 if (loaded < 0)
280 return -1;
281 if (loaded == 0)
282 return total;
283 count -= loaded;
284 p += loaded;
285 total += loaded;
286 offset += loaded;
289 return total;
292 int xdup(int fd)
294 int ret = dup(fd);
295 if (ret < 0)
296 die_errno("dup failed");
297 return ret;
300 FILE *xfdopen(int fd, const char *mode)
302 FILE *stream = fdopen(fd, mode);
303 if (stream == NULL)
304 die_errno("Out of memory? fdopen failed");
305 return stream;
308 int xmkstemp(char *template)
310 int fd;
311 char origtemplate[PATH_MAX];
312 strlcpy(origtemplate, template, sizeof(origtemplate));
314 fd = mkstemp(template);
315 if (fd < 0) {
316 int saved_errno = errno;
317 const char *nonrelative_template;
319 if (strlen(template) != strlen(origtemplate))
320 template = origtemplate;
322 nonrelative_template = absolute_path(template);
323 errno = saved_errno;
324 die_errno("Unable to create temporary file '%s'",
325 nonrelative_template);
327 return fd;
330 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
331 int git_mkstemp(char *path, size_t len, const char *template)
333 const char *tmp;
334 size_t n;
336 tmp = getenv("TMPDIR");
337 if (!tmp)
338 tmp = "/tmp";
339 n = snprintf(path, len, "%s/%s", tmp, template);
340 if (len <= n) {
341 errno = ENAMETOOLONG;
342 return -1;
344 return mkstemp(path);
347 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
348 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
350 const char *tmp;
351 size_t n;
353 tmp = getenv("TMPDIR");
354 if (!tmp)
355 tmp = "/tmp";
356 n = snprintf(path, len, "%s/%s", tmp, template);
357 if (len <= n) {
358 errno = ENAMETOOLONG;
359 return -1;
361 return mkstemps(path, suffix_len);
364 /* Adapted from libiberty's mkstemp.c. */
366 #undef TMP_MAX
367 #define TMP_MAX 16384
369 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
371 static const char letters[] =
372 "abcdefghijklmnopqrstuvwxyz"
373 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
374 "0123456789";
375 static const int num_letters = 62;
376 uint64_t value;
377 struct timeval tv;
378 char *template;
379 size_t len;
380 int fd, count;
382 len = strlen(pattern);
384 if (len < 6 + suffix_len) {
385 errno = EINVAL;
386 return -1;
389 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
390 errno = EINVAL;
391 return -1;
395 * Replace pattern's XXXXXX characters with randomness.
396 * Try TMP_MAX different filenames.
398 gettimeofday(&tv, NULL);
399 value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
400 template = &pattern[len - 6 - suffix_len];
401 for (count = 0; count < TMP_MAX; ++count) {
402 uint64_t v = value;
403 /* Fill in the random bits. */
404 template[0] = letters[v % num_letters]; v /= num_letters;
405 template[1] = letters[v % num_letters]; v /= num_letters;
406 template[2] = letters[v % num_letters]; v /= num_letters;
407 template[3] = letters[v % num_letters]; v /= num_letters;
408 template[4] = letters[v % num_letters]; v /= num_letters;
409 template[5] = letters[v % num_letters]; v /= num_letters;
411 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
412 if (fd >= 0)
413 return fd;
415 * Fatal error (EPERM, ENOSPC etc).
416 * It doesn't make sense to loop.
418 if (errno != EEXIST)
419 break;
421 * This is a random value. It is only necessary that
422 * the next TMP_MAX values generated by adding 7777 to
423 * VALUE are different with (module 2^32).
425 value += 7777;
427 /* We return the null string if we can't find a unique file name. */
428 pattern[0] = '\0';
429 return -1;
432 int git_mkstemp_mode(char *pattern, int mode)
434 /* mkstemp is just mkstemps with no suffix */
435 return git_mkstemps_mode(pattern, 0, mode);
438 #ifdef NO_MKSTEMPS
439 int gitmkstemps(char *pattern, int suffix_len)
441 return git_mkstemps_mode(pattern, suffix_len, 0600);
443 #endif
445 int xmkstemp_mode(char *template, int mode)
447 int fd;
448 char origtemplate[PATH_MAX];
449 strlcpy(origtemplate, template, sizeof(origtemplate));
451 fd = git_mkstemp_mode(template, mode);
452 if (fd < 0) {
453 int saved_errno = errno;
454 const char *nonrelative_template;
456 if (!template[0])
457 template = origtemplate;
459 nonrelative_template = absolute_path(template);
460 errno = saved_errno;
461 die_errno("Unable to create temporary file '%s'",
462 nonrelative_template);
464 return fd;
467 static int warn_if_unremovable(const char *op, const char *file, int rc)
469 int err;
470 if (!rc || errno == ENOENT)
471 return 0;
472 err = errno;
473 warning("unable to %s %s: %s", op, file, strerror(errno));
474 errno = err;
475 return rc;
478 int unlink_or_msg(const char *file, struct strbuf *err)
480 int rc = unlink(file);
482 assert(err);
484 if (!rc || errno == ENOENT)
485 return 0;
487 strbuf_addf(err, "unable to unlink %s: %s",
488 file, strerror(errno));
489 return -1;
492 int unlink_or_warn(const char *file)
494 return warn_if_unremovable("unlink", file, unlink(file));
497 int rmdir_or_warn(const char *file)
499 return warn_if_unremovable("rmdir", file, rmdir(file));
502 int remove_or_warn(unsigned int mode, const char *file)
504 return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
507 void warn_on_inaccessible(const char *path)
509 warning(_("unable to access '%s': %s"), path, strerror(errno));
512 static int access_error_is_ok(int err, unsigned flag)
514 return err == ENOENT || err == ENOTDIR ||
515 ((flag & ACCESS_EACCES_OK) && err == EACCES);
518 int access_or_warn(const char *path, int mode, unsigned flag)
520 int ret = access(path, mode);
521 if (ret && !access_error_is_ok(errno, flag))
522 warn_on_inaccessible(path);
523 return ret;
526 int access_or_die(const char *path, int mode, unsigned flag)
528 int ret = access(path, mode);
529 if (ret && !access_error_is_ok(errno, flag))
530 die_errno(_("unable to access '%s'"), path);
531 return ret;
534 struct passwd *xgetpwuid_self(void)
536 struct passwd *pw;
538 errno = 0;
539 pw = getpwuid(getuid());
540 if (!pw)
541 die(_("unable to look up current user in the passwd file: %s"),
542 errno ? strerror(errno) : _("no such user"));
543 return pw;
546 char *xgetcwd(void)
548 struct strbuf sb = STRBUF_INIT;
549 if (strbuf_getcwd(&sb))
550 die_errno(_("unable to get current working directory"));
551 return strbuf_detach(&sb, NULL);