1 /*
2 * Various trivial helper wrappers around standard functions
3 */
4 #include "cache.h"
6 static void do_nothing(size_t size)
7 {
8 }
10 static void (*try_to_free_routine)(size_t size) = do_nothing;
12 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
13 {
14 try_to_free_t old = try_to_free_routine;
15 try_to_free_routine = routine;
16 return old;
17 }
19 char *xstrdup(const char *str)
20 {
21 char *ret = strdup(str);
22 if (!ret) {
23 try_to_free_routine(strlen(str) + 1);
24 ret = strdup(str);
25 if (!ret)
26 die("Out of memory, strdup failed");
27 }
28 return ret;
29 }
31 void *xmalloc(size_t size)
32 {
33 void *ret = malloc(size);
34 if (!ret && !size)
35 ret = malloc(1);
36 if (!ret) {
37 try_to_free_routine(size);
38 ret = malloc(size);
39 if (!ret && !size)
40 ret = malloc(1);
41 if (!ret)
42 die("Out of memory, malloc failed (tried to allocate %lu bytes)",
43 (unsigned long)size);
44 }
45 #ifdef XMALLOC_POISON
46 memset(ret, 0xA5, size);
47 #endif
48 return ret;
49 }
51 void *xmallocz(size_t size)
52 {
53 void *ret;
54 if (size + 1 < size)
55 die("Data too large to fit into virtual memory space.");
56 ret = xmalloc(size + 1);
57 ((char*)ret)[size] = 0;
58 return ret;
59 }
61 /*
62 * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
63 * "data" to the allocated memory, zero terminates the allocated memory,
64 * and returns a pointer to the allocated memory. If the allocation fails,
65 * the program dies.
66 */
67 void *xmemdupz(const void *data, size_t len)
68 {
69 return memcpy(xmallocz(len), data, len);
70 }
72 char *xstrndup(const char *str, size_t len)
73 {
74 char *p = memchr(str, '\0', len);
75 return xmemdupz(str, p ? p - str : len);
76 }
78 void *xrealloc(void *ptr, size_t size)
79 {
80 void *ret = realloc(ptr, size);
81 if (!ret && !size)
82 ret = realloc(ptr, 1);
83 if (!ret) {
84 try_to_free_routine(size);
85 ret = realloc(ptr, size);
86 if (!ret && !size)
87 ret = realloc(ptr, 1);
88 if (!ret)
89 die("Out of memory, realloc failed");
90 }
91 return ret;
92 }
94 void *xcalloc(size_t nmemb, size_t size)
95 {
96 void *ret = calloc(nmemb, size);
97 if (!ret && (!nmemb || !size))
98 ret = calloc(1, 1);
99 if (!ret) {
100 try_to_free_routine(nmemb * size);
101 ret = calloc(nmemb, size);
102 if (!ret && (!nmemb || !size))
103 ret = calloc(1, 1);
104 if (!ret)
105 die("Out of memory, calloc failed");
106 }
107 return ret;
108 }
110 /*
111 * xread() is the same a read(), but it automatically restarts read()
112 * operations with a recoverable error (EAGAIN and EINTR). xread()
113 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
114 */
115 ssize_t xread(int fd, void *buf, size_t len)
116 {
117 ssize_t nr;
118 while (1) {
119 nr = read(fd, buf, len);
120 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
121 continue;
122 return nr;
123 }
124 }
126 /*
127 * xwrite() is the same a write(), but it automatically restarts write()
128 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
129 * GUARANTEE that "len" bytes is written even if the operation is successful.
130 */
131 ssize_t xwrite(int fd, const void *buf, size_t len)
132 {
133 ssize_t nr;
134 while (1) {
135 nr = write(fd, buf, len);
136 if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
137 continue;
138 return nr;
139 }
140 }
142 ssize_t read_in_full(int fd, void *buf, size_t count)
143 {
144 char *p = buf;
145 ssize_t total = 0;
147 while (count > 0) {
148 ssize_t loaded = xread(fd, p, count);
149 if (loaded <= 0)
150 return total ? total : loaded;
151 count -= loaded;
152 p += loaded;
153 total += loaded;
154 }
156 return total;
157 }
159 ssize_t write_in_full(int fd, const void *buf, size_t count)
160 {
161 const char *p = buf;
162 ssize_t total = 0;
164 while (count > 0) {
165 ssize_t written = xwrite(fd, p, count);
166 if (written < 0)
167 return -1;
168 if (!written) {
169 errno = ENOSPC;
170 return -1;
171 }
172 count -= written;
173 p += written;
174 total += written;
175 }
177 return total;
178 }
180 int xdup(int fd)
181 {
182 int ret = dup(fd);
183 if (ret < 0)
184 die_errno("dup failed");
185 return ret;
186 }
188 FILE *xfdopen(int fd, const char *mode)
189 {
190 FILE *stream = fdopen(fd, mode);
191 if (stream == NULL)
192 die_errno("Out of memory? fdopen failed");
193 return stream;
194 }
196 int xmkstemp(char *template)
197 {
198 int fd;
200 fd = mkstemp(template);
201 if (fd < 0)
202 die_errno("Unable to create temporary file");
203 return fd;
204 }
206 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
207 int git_mkstemp(char *path, size_t len, const char *template)
208 {
209 const char *tmp;
210 size_t n;
212 tmp = getenv("TMPDIR");
213 if (!tmp)
214 tmp = "/tmp";
215 n = snprintf(path, len, "%s/%s", tmp, template);
216 if (len <= n) {
217 errno = ENAMETOOLONG;
218 return -1;
219 }
220 return mkstemp(path);
221 }
223 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
224 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
225 {
226 const char *tmp;
227 size_t n;
229 tmp = getenv("TMPDIR");
230 if (!tmp)
231 tmp = "/tmp";
232 n = snprintf(path, len, "%s/%s", tmp, template);
233 if (len <= n) {
234 errno = ENAMETOOLONG;
235 return -1;
236 }
237 return mkstemps(path, suffix_len);
238 }
240 /* Adapted from libiberty's mkstemp.c. */
242 #undef TMP_MAX
243 #define TMP_MAX 16384
245 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
246 {
247 static const char letters[] =
248 "abcdefghijklmnopqrstuvwxyz"
249 "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
250 "0123456789";
251 static const int num_letters = 62;
252 uint64_t value;
253 struct timeval tv;
254 char *template;
255 size_t len;
256 int fd, count;
258 len = strlen(pattern);
260 if (len < 6 + suffix_len) {
261 errno = EINVAL;
262 return -1;
263 }
265 if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
266 errno = EINVAL;
267 return -1;
268 }
270 /*
271 * Replace pattern's XXXXXX characters with randomness.
272 * Try TMP_MAX different filenames.
273 */
274 gettimeofday(&tv, NULL);
275 value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
276 template = &pattern[len - 6 - suffix_len];
277 for (count = 0; count < TMP_MAX; ++count) {
278 uint64_t v = value;
279 /* Fill in the random bits. */
280 template[0] = letters[v % num_letters]; v /= num_letters;
281 template[1] = letters[v % num_letters]; v /= num_letters;
282 template[2] = letters[v % num_letters]; v /= num_letters;
283 template[3] = letters[v % num_letters]; v /= num_letters;
284 template[4] = letters[v % num_letters]; v /= num_letters;
285 template[5] = letters[v % num_letters]; v /= num_letters;
287 fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
288 if (fd > 0)
289 return fd;
290 /*
291 * Fatal error (EPERM, ENOSPC etc).
292 * It doesn't make sense to loop.
293 */
294 if (errno != EEXIST)
295 break;
296 /*
297 * This is a random value. It is only necessary that
298 * the next TMP_MAX values generated by adding 7777 to
299 * VALUE are different with (module 2^32).
300 */
301 value += 7777;
302 }
303 /* We return the null string if we can't find a unique file name. */
304 pattern[0] = '\0';
305 return -1;
306 }
308 int git_mkstemp_mode(char *pattern, int mode)
309 {
310 /* mkstemp is just mkstemps with no suffix */
311 return git_mkstemps_mode(pattern, 0, mode);
312 }
314 int gitmkstemps(char *pattern, int suffix_len)
315 {
316 return git_mkstemps_mode(pattern, suffix_len, 0600);
317 }
319 int xmkstemp_mode(char *template, int mode)
320 {
321 int fd;
323 fd = git_mkstemp_mode(template, mode);
324 if (fd < 0)
325 die_errno("Unable to create temporary file");
326 return fd;
327 }
329 static int warn_if_unremovable(const char *op, const char *file, int rc)
330 {
331 if (rc < 0) {
332 int err = errno;
333 if (ENOENT != err) {
334 warning("unable to %s %s: %s",
335 op, file, strerror(errno));
336 errno = err;
337 }
338 }
339 return rc;
340 }
342 int unlink_or_warn(const char *file)
343 {
344 return warn_if_unremovable("unlink", file, unlink(file));
345 }
347 int rmdir_or_warn(const char *file)
348 {
349 return warn_if_unremovable("rmdir", file, rmdir(file));
350 }
352 int remove_or_warn(unsigned int mode, const char *file)
353 {
354 return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
355 }