Git 2.1
[git.git] / wrapper.c
1 /*
2 * Various trivial helper wrappers around standard functions
3 */
4 #include "cache.h"
5
6 static void do_nothing(size_t size)
7 {
8 }
9
10 static void (*try_to_free_routine)(size_t size) = do_nothing;
11
12 static void memory_limit_check(size_t size)
13 {
14 static int limit = -1;
15 if (limit == -1) {
16 const char *env = getenv("GIT_ALLOC_LIMIT");
17 limit = env ? atoi(env) * 1024 : 0;
18 }
19 if (limit && size > limit)
20 die("attempting to allocate %"PRIuMAX" over limit %d",
21 (intmax_t)size, limit);
22 }
23
24 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
25 {
26 try_to_free_t old = try_to_free_routine;
27 if (!routine)
28 routine = do_nothing;
29 try_to_free_routine = routine;
30 return old;
31 }
32
33 char *xstrdup(const char *str)
34 {
35 char *ret = strdup(str);
36 if (!ret) {
37 try_to_free_routine(strlen(str) + 1);
38 ret = strdup(str);
39 if (!ret)
40 die("Out of memory, strdup failed");
41 }
42 return ret;
43 }
44
45 void *xmalloc(size_t size)
46 {
47 void *ret;
48
49 memory_limit_check(size);
50 ret = malloc(size);
51 if (!ret && !size)
52 ret = malloc(1);
53 if (!ret) {
54 try_to_free_routine(size);
55 ret = malloc(size);
56 if (!ret && !size)
57 ret = malloc(1);
58 if (!ret)
59 die("Out of memory, malloc failed (tried to allocate %lu bytes)",
60 (unsigned long)size);
61 }
62 #ifdef XMALLOC_POISON
63 memset(ret, 0xA5, size);
64 #endif
65 return ret;
66 }
67
68 void *xmallocz(size_t size)
69 {
70 void *ret;
71 if (unsigned_add_overflows(size, 1))
72 die("Data too large to fit into virtual memory space.");
73 ret = xmalloc(size + 1);
74 ((char*)ret)[size] = 0;
75 return ret;
76 }
77
78 /*
79 * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
80 * "data" to the allocated memory, zero terminates the allocated memory,
81 * and returns a pointer to the allocated memory. If the allocation fails,
82 * the program dies.
83 */
84 void *xmemdupz(const void *data, size_t len)
85 {
86 return memcpy(xmallocz(len), data, len);
87 }
88
89 char *xstrndup(const char *str, size_t len)
90 {
91 char *p = memchr(str, '\0', len);
92 return xmemdupz(str, p ? p - str : len);
93 }
94
95 void *xrealloc(void *ptr, size_t size)
96 {
97 void *ret;
98
99 memory_limit_check(size);
100 ret = realloc(ptr, size);
101 if (!ret && !size)
102 ret = realloc(ptr, 1);
103 if (!ret) {
104 try_to_free_routine(size);
105 ret = realloc(ptr, size);
106 if (!ret && !size)
107 ret = realloc(ptr, 1);
108 if (!ret)
109 die("Out of memory, realloc failed");
110 }
111 return ret;
112 }
113
114 void *xcalloc(size_t nmemb, size_t size)
115 {
116 void *ret;
117
118 memory_limit_check(size * nmemb);
119 ret = calloc(nmemb, size);
120 if (!ret && (!nmemb || !size))
121 ret = calloc(1, 1);
122 if (!ret) {
123 try_to_free_routine(nmemb * size);
124 ret = calloc(nmemb, size);
125 if (!ret && (!nmemb || !size))
126 ret = calloc(1, 1);
127 if (!ret)
128 die("Out of memory, calloc failed");
129 }
130 return ret;
131 }
132
133 /*
134 * Limit size of IO chunks, because huge chunks only cause pain. OS X
135 * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
136 * the absence of bugs, large chunks can result in bad latencies when
137 * you decide to kill the process.
138 */
139 #define MAX_IO_SIZE (8*1024*1024)
140
141 /*
142 * xread() is the same a read(), but it automatically restarts read()
143 * operations with a recoverable error (EAGAIN and EINTR). xread()
144 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
145 */
146 ssize_t xread(int fd, void *buf, size_t len)
147 {
148 ssize_t nr;
149 if (len > MAX_IO_SIZE)
150 len = MAX_IO_SIZE;
151 while (1) {
152 nr = read(fd, buf, len);
153 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
154 continue;
155 return nr;
156 }
157 }
158
159 /*
160 * xwrite() is the same a write(), but it automatically restarts write()
161 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
162 * GUARANTEE that "len" bytes is written even if the operation is successful.
163 */
164 ssize_t xwrite(int fd, const void *buf, size_t len)
165 {
166 ssize_t nr;
167 if (len > MAX_IO_SIZE)
168 len = MAX_IO_SIZE;
169 while (1) {
170 nr = write(fd, buf, len);
171 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
172 continue;
173 return nr;
174 }
175 }
176
177 /*
178 * xpread() is the same as pread(), but it automatically restarts pread()
179 * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
180 * NOT GUARANTEE that "len" bytes is read even if the data is available.
181 */
182 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
183 {
184 ssize_t nr;
185 if (len > MAX_IO_SIZE)
186 len = MAX_IO_SIZE;
187 while (1) {
188 nr = pread(fd, buf, len, offset);
189 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
190 continue;
191 return nr;
192 }
193 }
194
195 ssize_t read_in_full(int fd, void *buf, size_t count)
196 {
197 char *p = buf;
198 ssize_t total = 0;
199
200 while (count > 0) {
201 ssize_t loaded = xread(fd, p, count);
202 if (loaded < 0)
203 return -1;
204 if (loaded == 0)
205 return total;
206 count -= loaded;
207 p += loaded;
208 total += loaded;
209 }
210
211 return total;
212 }
213
214 ssize_t write_in_full(int fd, const void *buf, size_t count)
215 {
216 const char *p = buf;
217 ssize_t total = 0;
218
219 while (count > 0) {
220 ssize_t written = xwrite(fd, p, count);
221 if (written < 0)
222 return -1;
223 if (!written) {
224 errno = ENOSPC;
225 return -1;
226 }
227 count -= written;
228 p += written;
229 total += written;
230 }
231
232 return total;
233 }
234
235 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
236 {
237 char *p = buf;
238 ssize_t total = 0;
239
240 while (count > 0) {
241 ssize_t loaded = xpread(fd, p, count, offset);
242 if (loaded < 0)
243 return -1;
244 if (loaded == 0)
245 return total;
246 count -= loaded;
247 p += loaded;
248 total += loaded;
249 offset += loaded;
250 }
251
252 return total;
253 }
254
255 int xdup(int fd)
256 {
257 int ret = dup(fd);
258 if (ret < 0)
259 die_errno("dup failed");
260 return ret;
261 }
262
263 FILE *xfdopen(int fd, const char *mode)
264 {
265 FILE *stream = fdopen(fd, mode);
266 if (stream == NULL)
267 die_errno("Out of memory? fdopen failed");
268 return stream;
269 }
270
271 int xmkstemp(char *template)
272 {
273 int fd;
274 char origtemplate[PATH_MAX];
275 strlcpy(origtemplate, template, sizeof(origtemplate));
276
277 fd = mkstemp(template);
278 if (fd < 0) {
279 int saved_errno = errno;
280 const char *nonrelative_template;
281
282 if (strlen(template) != strlen(origtemplate))
283 template = origtemplate;
284
285 nonrelative_template = absolute_path(template);
286 errno = saved_errno;
287 die_errno("Unable to create temporary file '%s'",
288 nonrelative_template);
289 }
290 return fd;
291 }
292
293 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
294 int git_mkstemp(char *path, size_t len, const char *template)
295 {
296 const char *tmp;
297 size_t n;
298
299 tmp = getenv("TMPDIR");
300 if (!tmp)
301 tmp = "/tmp";
302 n = snprintf(path, len, "%s/%s", tmp, template);
303 if (len <= n) {
304 errno = ENAMETOOLONG;
305 return -1;
306 }
307 return mkstemp(path);
308 }
309
310 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
311 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
312 {
313 const char *tmp;
314 size_t n;
315
316 tmp = getenv("TMPDIR");
317 if (!tmp)
318 tmp = "/tmp";
319 n = snprintf(path, len, "%s/%s", tmp, template);
320 if (len <= n) {
321 errno = ENAMETOOLONG;
322 return -1;
323 }
324 return mkstemps(path, suffix_len);
325 }
326
327 /* Adapted from libiberty's mkstemp.c. */
328
329 #undef TMP_MAX
330 #define TMP_MAX 16384
331
332 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
333 {
334 static const char letters[] =
335 "abcdefghijklmnopqrstuvwxyz"
336 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
337 "0123456789";
338 static const int num_letters = 62;
339 uint64_t value;
340 struct timeval tv;
341 char *template;
342 size_t len;
343 int fd, count;
344
345 len = strlen(pattern);
346
347 if (len < 6 + suffix_len) {
348 errno = EINVAL;
349 return -1;
350 }
351
352 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
353 errno = EINVAL;
354 return -1;
355 }
356
357 /*
358 * Replace pattern's XXXXXX characters with randomness.
359 * Try TMP_MAX different filenames.
360 */
361 gettimeofday(&tv, NULL);
362 value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
363 template = &pattern[len - 6 - suffix_len];
364 for (count = 0; count < TMP_MAX; ++count) {
365 uint64_t v = value;
366 /* Fill in the random bits. */
367 template[0] = letters[v % num_letters]; v /= num_letters;
368 template[1] = letters[v % num_letters]; v /= num_letters;
369 template[2] = letters[v % num_letters]; v /= num_letters;
370 template[3] = letters[v % num_letters]; v /= num_letters;
371 template[4] = letters[v % num_letters]; v /= num_letters;
372 template[5] = letters[v % num_letters]; v /= num_letters;
373
374 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
375 if (fd >= 0)
376 return fd;
377 /*
378 * Fatal error (EPERM, ENOSPC etc).
379 * It doesn't make sense to loop.
380 */
381 if (errno != EEXIST)
382 break;
383 /*
384 * This is a random value. It is only necessary that
385 * the next TMP_MAX values generated by adding 7777 to
386 * VALUE are different with (module 2^32).
387 */
388 value += 7777;
389 }
390 /* We return the null string if we can't find a unique file name. */
391 pattern[0] = '\0';
392 return -1;
393 }
394
395 int git_mkstemp_mode(char *pattern, int mode)
396 {
397 /* mkstemp is just mkstemps with no suffix */
398 return git_mkstemps_mode(pattern, 0, mode);
399 }
400
401 #ifdef NO_MKSTEMPS
402 int gitmkstemps(char *pattern, int suffix_len)
403 {
404 return git_mkstemps_mode(pattern, suffix_len, 0600);
405 }
406 #endif
407
408 int xmkstemp_mode(char *template, int mode)
409 {
410 int fd;
411 char origtemplate[PATH_MAX];
412 strlcpy(origtemplate, template, sizeof(origtemplate));
413
414 fd = git_mkstemp_mode(template, mode);
415 if (fd < 0) {
416 int saved_errno = errno;
417 const char *nonrelative_template;
418
419 if (!template[0])
420 template = origtemplate;
421
422 nonrelative_template = absolute_path(template);
423 errno = saved_errno;
424 die_errno("Unable to create temporary file '%s'",
425 nonrelative_template);
426 }
427 return fd;
428 }
429
430 static int warn_if_unremovable(const char *op, const char *file, int rc)
431 {
432 if (rc < 0) {
433 int err = errno;
434 if (ENOENT != err) {
435 warning("unable to %s %s: %s",
436 op, file, strerror(errno));
437 errno = err;
438 }
439 }
440 return rc;
441 }
442
443 int unlink_or_warn(const char *file)
444 {
445 return warn_if_unremovable("unlink", file, unlink(file));
446 }
447
448 int rmdir_or_warn(const char *file)
449 {
450 return warn_if_unremovable("rmdir", file, rmdir(file));
451 }
452
453 int remove_or_warn(unsigned int mode, const char *file)
454 {
455 return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
456 }
457
458 void warn_on_inaccessible(const char *path)
459 {
460 warning(_("unable to access '%s': %s"), path, strerror(errno));
461 }
462
463 static int access_error_is_ok(int err, unsigned flag)
464 {
465 return err == ENOENT || err == ENOTDIR ||
466 ((flag & ACCESS_EACCES_OK) && err == EACCES);
467 }
468
469 int access_or_warn(const char *path, int mode, unsigned flag)
470 {
471 int ret = access(path, mode);
472 if (ret && !access_error_is_ok(errno, flag))
473 warn_on_inaccessible(path);
474 return ret;
475 }
476
477 int access_or_die(const char *path, int mode, unsigned flag)
478 {
479 int ret = access(path, mode);
480 if (ret && !access_error_is_ok(errno, flag))
481 die_errno(_("unable to access '%s'"), path);
482 return ret;
483 }
484
485 struct passwd *xgetpwuid_self(void)
486 {
487 struct passwd *pw;
488
489 errno = 0;
490 pw = getpwuid(getuid());
491 if (!pw)
492 die(_("unable to look up current user in the passwd file: %s"),
493 errno ? strerror(errno) : _("no such user"));
494 return pw;
495 }