Merge git://ozlabs.org/~paulus/gitk
[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 int memory_limit_check(size_t size, int gentle)
13 {
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;
19 }
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);
28 }
29 return 0;
30 }
31
32 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
33 {
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;
39 }
40
41 char *xstrdup(const char *str)
42 {
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");
49 }
50 return ret;
51 }
52
53 static void *do_xmalloc(size_t size, int gentle)
54 {
55 void *ret;
56
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;
75 }
76 }
77 }
78 #ifdef XMALLOC_POISON
79 memset(ret, 0xA5, size);
80 #endif
81 return ret;
82 }
83
84 void *xmalloc(size_t size)
85 {
86 return do_xmalloc(size, 0);
87 }
88
89 static void *do_xmallocz(size_t size, int gentle)
90 {
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.");
98 }
99 ret = do_xmalloc(size + 1, gentle);
100 if (ret)
101 ((char*)ret)[size] = 0;
102 return ret;
103 }
104
105 void *xmallocz(size_t size)
106 {
107 return do_xmallocz(size, 0);
108 }
109
110 void *xmallocz_gently(size_t size)
111 {
112 return do_xmallocz(size, 1);
113 }
114
115 /*
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.
120 */
121 void *xmemdupz(const void *data, size_t len)
122 {
123 return memcpy(xmallocz(len), data, len);
124 }
125
126 char *xstrndup(const char *str, size_t len)
127 {
128 char *p = memchr(str, '\0', len);
129 return xmemdupz(str, p ? p - str : len);
130 }
131
132 void *xrealloc(void *ptr, size_t size)
133 {
134 void *ret;
135
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");
147 }
148 return ret;
149 }
150
151 void *xcalloc(size_t nmemb, size_t size)
152 {
153 void *ret;
154
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");
166 }
167 return ret;
168 }
169
170 /*
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.
175 */
176 #define MAX_IO_SIZE (8*1024*1024)
177
178 /*
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.
182 */
183 ssize_t xread(int fd, void *buf, size_t len)
184 {
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;
193 }
194 }
195
196 /*
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.
200 */
201 ssize_t xwrite(int fd, const void *buf, size_t len)
202 {
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;
211 }
212 }
213
214 /*
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.
218 */
219 ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
220 {
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;
229 }
230 }
231
232 ssize_t read_in_full(int fd, void *buf, size_t count)
233 {
234 char *p = buf;
235 ssize_t total = 0;
236
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;
246 }
247
248 return total;
249 }
250
251 ssize_t write_in_full(int fd, const void *buf, size_t count)
252 {
253 const char *p = buf;
254 ssize_t total = 0;
255
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;
263 }
264 count -= written;
265 p += written;
266 total += written;
267 }
268
269 return total;
270 }
271
272 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
273 {
274 char *p = buf;
275 ssize_t total = 0;
276
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;
287 }
288
289 return total;
290 }
291
292 int xdup(int fd)
293 {
294 int ret = dup(fd);
295 if (ret < 0)
296 die_errno("dup failed");
297 return ret;
298 }
299
300 FILE *xfdopen(int fd, const char *mode)
301 {
302 FILE *stream = fdopen(fd, mode);
303 if (stream == NULL)
304 die_errno("Out of memory? fdopen failed");
305 return stream;
306 }
307
308 int xmkstemp(char *template)
309 {
310 int fd;
311 char origtemplate[PATH_MAX];
312 strlcpy(origtemplate, template, sizeof(origtemplate));
313
314 fd = mkstemp(template);
315 if (fd < 0) {
316 int saved_errno = errno;
317 const char *nonrelative_template;
318
319 if (strlen(template) != strlen(origtemplate))
320 template = origtemplate;
321
322 nonrelative_template = absolute_path(template);
323 errno = saved_errno;
324 die_errno("Unable to create temporary file '%s'",
325 nonrelative_template);
326 }
327 return fd;
328 }
329
330 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
331 int git_mkstemp(char *path, size_t len, const char *template)
332 {
333 const char *tmp;
334 size_t n;
335
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;
343 }
344 return mkstemp(path);
345 }
346
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)
349 {
350 const char *tmp;
351 size_t n;
352
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;
360 }
361 return mkstemps(path, suffix_len);
362 }
363
364 /* Adapted from libiberty's mkstemp.c. */
365
366 #undef TMP_MAX
367 #define TMP_MAX 16384
368
369 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
370 {
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;
381
382 len = strlen(pattern);
383
384 if (len < 6 + suffix_len) {
385 errno = EINVAL;
386 return -1;
387 }
388
389 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
390 errno = EINVAL;
391 return -1;
392 }
393
394 /*
395 * Replace pattern's XXXXXX characters with randomness.
396 * Try TMP_MAX different filenames.
397 */
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;
410
411 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
412 if (fd >= 0)
413 return fd;
414 /*
415 * Fatal error (EPERM, ENOSPC etc).
416 * It doesn't make sense to loop.
417 */
418 if (errno != EEXIST)
419 break;
420 /*
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).
424 */
425 value += 7777;
426 }
427 /* We return the null string if we can't find a unique file name. */
428 pattern[0] = '\0';
429 return -1;
430 }
431
432 int git_mkstemp_mode(char *pattern, int mode)
433 {
434 /* mkstemp is just mkstemps with no suffix */
435 return git_mkstemps_mode(pattern, 0, mode);
436 }
437
438 #ifdef NO_MKSTEMPS
439 int gitmkstemps(char *pattern, int suffix_len)
440 {
441 return git_mkstemps_mode(pattern, suffix_len, 0600);
442 }
443 #endif
444
445 int xmkstemp_mode(char *template, int mode)
446 {
447 int fd;
448 char origtemplate[PATH_MAX];
449 strlcpy(origtemplate, template, sizeof(origtemplate));
450
451 fd = git_mkstemp_mode(template, mode);
452 if (fd < 0) {
453 int saved_errno = errno;
454 const char *nonrelative_template;
455
456 if (!template[0])
457 template = origtemplate;
458
459 nonrelative_template = absolute_path(template);
460 errno = saved_errno;
461 die_errno("Unable to create temporary file '%s'",
462 nonrelative_template);
463 }
464 return fd;
465 }
466
467 static int warn_if_unremovable(const char *op, const char *file, int rc)
468 {
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;
476 }
477
478 int unlink_or_msg(const char *file, struct strbuf *err)
479 {
480 int rc = unlink(file);
481
482 assert(err);
483
484 if (!rc || errno == ENOENT)
485 return 0;
486
487 strbuf_addf(err, "unable to unlink %s: %s",
488 file, strerror(errno));
489 return -1;
490 }
491
492 int unlink_or_warn(const char *file)
493 {
494 return warn_if_unremovable("unlink", file, unlink(file));
495 }
496
497 int rmdir_or_warn(const char *file)
498 {
499 return warn_if_unremovable("rmdir", file, rmdir(file));
500 }
501
502 int remove_or_warn(unsigned int mode, const char *file)
503 {
504 return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
505 }
506
507 void warn_on_inaccessible(const char *path)
508 {
509 warning(_("unable to access '%s': %s"), path, strerror(errno));
510 }
511
512 static int access_error_is_ok(int err, unsigned flag)
513 {
514 return err == ENOENT || err == ENOTDIR ||
515 ((flag & ACCESS_EACCES_OK) && err == EACCES);
516 }
517
518 int access_or_warn(const char *path, int mode, unsigned flag)
519 {
520 int ret = access(path, mode);
521 if (ret && !access_error_is_ok(errno, flag))
522 warn_on_inaccessible(path);
523 return ret;
524 }
525
526 int access_or_die(const char *path, int mode, unsigned flag)
527 {
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;
532 }
533
534 struct passwd *xgetpwuid_self(void)
535 {
536 struct passwd *pw;
537
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;
544 }
545
546 char *xgetcwd(void)
547 {
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);
552 }