aboutsummaryrefslogtreecommitdiff
path: root/wrapper.c
blob: 4c147d6c48c000bab636fad3edc2fe7da6670948 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
/*
 * Various trivial helper wrappers around standard functions
 */
#include "cache.h"

static void do_nothing(size_t size)
{
}

static void (*try_to_free_routine)(size_t size) = do_nothing;

try_to_free_t set_try_to_free_routine(try_to_free_t routine)
{
	try_to_free_t old = try_to_free_routine;
	if (!routine)
		routine = do_nothing;
	try_to_free_routine = routine;
	return old;
}

char *xstrdup(const char *str)
{
	char *ret = strdup(str);
	if (!ret) {
		try_to_free_routine(strlen(str) + 1);
		ret = strdup(str);
		if (!ret)
			die("Out of memory, strdup failed");
	}
	return ret;
}

void *xmalloc(size_t size)
{
	void *ret = malloc(size);
	if (!ret && !size)
		ret = malloc(1);
	if (!ret) {
		try_to_free_routine(size);
		ret = malloc(size);
		if (!ret && !size)
			ret = malloc(1);
		if (!ret)
			die("Out of memory, malloc failed (tried to allocate %lu bytes)",
			    (unsigned long)size);
	}
#ifdef XMALLOC_POISON
	memset(ret, 0xA5, size);
#endif
	return ret;
}

void *xmallocz(size_t size)
{
	void *ret;
	if (unsigned_add_overflows(size, 1))
		die("Data too large to fit into virtual memory space.");
	ret = xmalloc(size + 1);
	((char*)ret)[size] = 0;
	return ret;
}

/*
 * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
 * "data" to the allocated memory, zero terminates the allocated memory,
 * and returns a pointer to the allocated memory. If the allocation fails,
 * the program dies.
 */
void *xmemdupz(const void *data, size_t len)
{
	return memcpy(xmallocz(len), data, len);
}

char *xstrndup(const char *str, size_t len)
{
	char *p = memchr(str, '\0', len);
	return xmemdupz(str, p ? p - str : len);
}

void *xrealloc(void *ptr, size_t size)
{
	void *ret = realloc(ptr, size);
	if (!ret && !size)
		ret = realloc(ptr, 1);
	if (!ret) {
		try_to_free_routine(size);
		ret = realloc(ptr, size);
		if (!ret && !size)
			ret = realloc(ptr, 1);
		if (!ret)
			die("Out of memory, realloc failed");
	}
	return ret;
}

void *xcalloc(size_t nmemb, size_t size)
{
	void *ret = calloc(nmemb, size);
	if (!ret && (!nmemb || !size))
		ret = calloc(1, 1);
	if (!ret) {
		try_to_free_routine(nmemb * size);
		ret = calloc(nmemb, size);
		if (!ret && (!nmemb || !size))
			ret = calloc(1, 1);
		if (!ret)
			die("Out of memory, calloc failed");
	}
	return ret;
}

/*
 * xread() is the same a read(), but it automatically restarts read()
 * operations with a recoverable error (EAGAIN and EINTR). xread()
 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 */
ssize_t xread(int fd, void *buf, size_t len)
{
	ssize_t nr;
	while (1) {
		nr = read(fd, buf, len);
		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
			continue;
		return nr;
	}
}

/*
 * xwrite() is the same a write(), but it automatically restarts write()
 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 * GUARANTEE that "len" bytes is written even if the operation is successful.
 */
ssize_t xwrite(int fd, const void *buf, size_t len)
{
	ssize_t nr;
	while (1) {
		nr = write(fd, buf, len);
		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
			continue;
		return nr;
	}
}

ssize_t read_in_full(int fd, void *buf, size_t count)
{
	char *p = buf;
	ssize_t total = 0;

	while (count > 0) {
		ssize_t loaded = xread(fd, p, count);
		if (loaded <= 0)
			return total ? total : loaded;
		count -= loaded;
		p += loaded;
		total += loaded;
	}

	return total;
}

ssize_t write_in_full(int fd, const void *buf, size_t count)
{
	const char *p = buf;
	ssize_t total = 0;

	while (count > 0) {
		ssize_t written = xwrite(fd, p, count);
		if (written < 0)
			return -1;
		if (!written) {
			errno = ENOSPC;
			return -1;
		}
		count -= written;
		p += written;
		total += written;
	}

	return total;
}

int xdup(int fd)
{
	int ret = dup(fd);
	if (ret < 0)
		die_errno("dup failed");
	return ret;
}

FILE *xfdopen(int fd, const char *mode)
{
	FILE *stream = fdopen(fd, mode);
	if (stream == NULL)
		die_errno("Out of memory? fdopen failed");
	return stream;
}

int xmkstemp(char *template)
{
	int fd;
	char origtemplate[PATH_MAX];
	strlcpy(origtemplate, template, sizeof(origtemplate));

	fd = mkstemp(template);
	if (fd < 0) {
		int saved_errno = errno;
		const char *nonrelative_template;

		if (!template[0])
			template = origtemplate;

		nonrelative_template = make_nonrelative_path(template);
		errno = saved_errno;
		die_errno("Unable to create temporary file '%s'",
			nonrelative_template);
	}
	return fd;
}

/* git_mkstemp() - create tmp file honoring TMPDIR variable */
int git_mkstemp(char *path, size_t len, const char *template)
{
	const char *tmp;
	size_t n;

	tmp = getenv("TMPDIR");
	if (!tmp)
		tmp = "/tmp";
	n = snprintf(path, len, "%s/%s", tmp, template);
	if (len <= n) {
		errno = ENAMETOOLONG;
		return -1;
	}
	return mkstemp(path);
}

/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
{
	const char *tmp;
	size_t n;

	tmp = getenv("TMPDIR");
	if (!tmp)
		tmp = "/tmp";
	n = snprintf(path, len, "%s/%s", tmp, template);
	if (len <= n) {
		errno = ENAMETOOLONG;
		return -1;
	}
	return mkstemps(path, suffix_len);
}

/* Adapted from libiberty's mkstemp.c. */

#undef TMP_MAX
#define TMP_MAX 16384

int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
{
	static const char letters[] =
		"abcdefghijklmnopqrstuvwxyz"
		"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
		"0123456789";
	static const int num_letters = 62;
	uint64_t value;
	struct timeval tv;
	char *template;
	size_t len;
	int fd, count;

	len = strlen(pattern);

	if (len < 6 + suffix_len) {
		errno = EINVAL;
		return -1;
	}

	if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
		errno = EINVAL;
		return -1;
	}

	/*
	 * Replace pattern's XXXXXX characters with randomness.
	 * Try TMP_MAX different filenames.
	 */
	gettimeofday(&tv, NULL);
	value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
	template = &pattern[len - 6 - suffix_len];
	for (count = 0; count < TMP_MAX; ++count) {
		uint64_t v = value;
		/* Fill in the random bits. */
		template[0] = letters[v % num_letters]; v /= num_letters;
		template[1] = letters[v % num_letters]; v /= num_letters;
		template[2] = letters[v % num_letters]; v /= num_letters;
		template[3] = letters[v % num_letters]; v /= num_letters;
		template[4] = letters[v % num_letters]; v /= num_letters;
		template[5] = letters[v % num_letters]; v /= num_letters;

		fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
		if (fd > 0)
			return fd;
		/*
		 * Fatal error (EPERM, ENOSPC etc).
		 * It doesn't make sense to loop.
		 */
		if (errno != EEXIST)
			break;
		/*
		 * This is a random value.  It is only necessary that
		 * the next TMP_MAX values generated by adding 7777 to
		 * VALUE are different with (module 2^32).
		 */
		value += 7777;
	}
	/* We return the null string if we can't find a unique file name.  */
	pattern[0] = '\0';
	return -1;
}

int git_mkstemp_mode(char *pattern, int mode)
{
	/* mkstemp is just mkstemps with no suffix */
	return git_mkstemps_mode(pattern, 0, mode);
}

int gitmkstemps(char *pattern, int suffix_len)
{
	return git_mkstemps_mode(pattern, suffix_len, 0600);
}

int xmkstemp_mode(char *template, int mode)
{
	int fd;
	char origtemplate[PATH_MAX];
	strlcpy(origtemplate, template, sizeof(origtemplate));

	fd = git_mkstemp_mode(template, mode);
	if (fd < 0) {
		int saved_errno = errno;
		const char *nonrelative_template;

		if (!template[0])
			template = origtemplate;

		nonrelative_template = make_nonrelative_path(template);
		errno = saved_errno;
		die_errno("Unable to create temporary file '%s'",
			nonrelative_template);
	}
	return fd;
}

static int warn_if_unremovable(const char *op, const char *file, int rc)
{
	if (rc < 0) {
		int err = errno;
		if (ENOENT != err) {
			warning("unable to %s %s: %s",
				op, file, strerror(errno));
			errno = err;
		}
	}
	return rc;
}

int unlink_or_warn(const char *file)
{
	return warn_if_unremovable("unlink", file, unlink(file));
}

int rmdir_or_warn(const char *file)
{
	return warn_if_unremovable("rmdir", file, rmdir(file));
}

int remove_or_warn(unsigned int mode, const char *file)
{
	return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
}