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37ef15bb CB |
1 | /* liblxcapi |
2 | * | |
3 | * Copyright © 2018 Christian Brauner <christian.brauner@ubuntu.com>. | |
4 | * Copyright © 2018 Canonical Ltd. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2, as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along | |
16 | * with this program; if not, write to the Free Software Foundation, Inc., | |
17 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 | */ | |
19 | ||
d38dd64a CB |
20 | #ifndef _GNU_SOURCE |
21 | #define _GNU_SOURCE 1 | |
22 | #endif | |
37ef15bb CB |
23 | #include <errno.h> |
24 | #include <fcntl.h> | |
25 | #include <linux/magic.h> | |
26 | #include <stdlib.h> | |
27 | #include <sys/stat.h> | |
7c4d9466 | 28 | #include <sys/sendfile.h> |
37ef15bb CB |
29 | #include <sys/types.h> |
30 | ||
d38dd64a | 31 | #include "config.h" |
37ef15bb | 32 | #include "file_utils.h" |
37ef15bb | 33 | #include "macro.h" |
6400238d | 34 | #include "string_utils.h" |
37ef15bb | 35 | |
37ef15bb CB |
36 | int lxc_write_to_file(const char *filename, const void *buf, size_t count, |
37 | bool add_newline, mode_t mode) | |
38 | { | |
39 | int fd, saved_errno; | |
40 | ssize_t ret; | |
41 | ||
42 | fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT | O_CLOEXEC, mode); | |
43 | if (fd < 0) | |
44 | return -1; | |
45 | ||
46 | ret = lxc_write_nointr(fd, buf, count); | |
47 | if (ret < 0) | |
48 | goto out_error; | |
49 | ||
50 | if ((size_t)ret != count) | |
51 | goto out_error; | |
52 | ||
53 | if (add_newline) { | |
54 | ret = lxc_write_nointr(fd, "\n", 1); | |
55 | if (ret != 1) | |
56 | goto out_error; | |
57 | } | |
58 | ||
59 | close(fd); | |
60 | return 0; | |
61 | ||
62 | out_error: | |
63 | saved_errno = errno; | |
64 | close(fd); | |
65 | errno = saved_errno; | |
66 | return -1; | |
67 | } | |
68 | ||
69 | int lxc_read_from_file(const char *filename, void *buf, size_t count) | |
70 | { | |
71 | int fd = -1, saved_errno; | |
72 | ssize_t ret; | |
73 | ||
74 | fd = open(filename, O_RDONLY | O_CLOEXEC); | |
75 | if (fd < 0) | |
76 | return -1; | |
77 | ||
78 | if (!buf || !count) { | |
79 | char buf2[100]; | |
80 | size_t count2 = 0; | |
81 | ||
82 | while ((ret = lxc_read_nointr(fd, buf2, 100)) > 0) | |
83 | count2 += ret; | |
84 | ||
85 | if (ret >= 0) | |
86 | ret = count2; | |
87 | } else { | |
88 | memset(buf, 0, count); | |
89 | ret = lxc_read_nointr(fd, buf, count); | |
90 | } | |
91 | ||
92 | saved_errno = errno; | |
93 | close(fd); | |
94 | errno = saved_errno; | |
95 | return ret; | |
96 | } | |
97 | ||
98 | ssize_t lxc_write_nointr(int fd, const void *buf, size_t count) | |
99 | { | |
100 | ssize_t ret; | |
101 | again: | |
102 | ret = write(fd, buf, count); | |
103 | if (ret < 0 && errno == EINTR) | |
104 | goto again; | |
105 | ||
106 | return ret; | |
107 | } | |
108 | ||
28143f88 CB |
109 | ssize_t lxc_send_nointr(int sockfd, void *buf, size_t len, int flags) |
110 | { | |
111 | ssize_t ret; | |
112 | again: | |
113 | ret = send(sockfd, buf, len, flags); | |
114 | if (ret < 0 && errno == EINTR) | |
115 | goto again; | |
116 | ||
117 | return ret; | |
118 | } | |
119 | ||
37ef15bb CB |
120 | ssize_t lxc_read_nointr(int fd, void *buf, size_t count) |
121 | { | |
122 | ssize_t ret; | |
123 | again: | |
124 | ret = read(fd, buf, count); | |
125 | if (ret < 0 && errno == EINTR) | |
126 | goto again; | |
127 | ||
128 | return ret; | |
129 | } | |
130 | ||
de69edd1 CB |
131 | ssize_t lxc_recv_nointr(int sockfd, void *buf, size_t len, int flags) |
132 | { | |
133 | ssize_t ret; | |
134 | again: | |
135 | ret = recv(sockfd, buf, len, flags); | |
136 | if (ret < 0 && errno == EINTR) | |
137 | goto again; | |
138 | ||
139 | return ret; | |
140 | } | |
141 | ||
37ef15bb CB |
142 | ssize_t lxc_read_nointr_expect(int fd, void *buf, size_t count, const void *expected_buf) |
143 | { | |
144 | ssize_t ret; | |
145 | ||
146 | ret = lxc_read_nointr(fd, buf, count); | |
147 | if (ret <= 0) | |
148 | return ret; | |
149 | ||
150 | if ((size_t)ret != count) | |
151 | return -1; | |
152 | ||
153 | if (expected_buf && memcmp(buf, expected_buf, count) != 0) { | |
154 | errno = EINVAL; | |
155 | return -1; | |
156 | } | |
157 | ||
158 | return ret; | |
159 | } | |
160 | ||
161 | bool file_exists(const char *f) | |
162 | { | |
163 | struct stat statbuf; | |
164 | ||
165 | return stat(f, &statbuf) == 0; | |
166 | } | |
167 | ||
168 | int print_to_file(const char *file, const char *content) | |
169 | { | |
170 | FILE *f; | |
171 | int ret = 0; | |
172 | ||
173 | f = fopen(file, "w"); | |
174 | if (!f) | |
175 | return -1; | |
176 | ||
177 | if (fprintf(f, "%s", content) != strlen(content)) | |
178 | ret = -1; | |
179 | ||
180 | fclose(f); | |
181 | return ret; | |
182 | } | |
183 | ||
184 | int is_dir(const char *path) | |
185 | { | |
186 | struct stat statbuf; | |
187 | int ret; | |
188 | ||
189 | ret = stat(path, &statbuf); | |
190 | if (ret == 0 && S_ISDIR(statbuf.st_mode)) | |
191 | return 1; | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
196 | /* | |
197 | * Return the number of lines in file @fn, or -1 on error | |
198 | */ | |
199 | int lxc_count_file_lines(const char *fn) | |
200 | { | |
201 | FILE *f; | |
202 | char *line = NULL; | |
203 | size_t sz = 0; | |
204 | int n = 0; | |
205 | ||
206 | f = fopen_cloexec(fn, "r"); | |
207 | if (!f) | |
208 | return -1; | |
209 | ||
210 | while (getline(&line, &sz, f) != -1) { | |
211 | n++; | |
212 | } | |
213 | ||
214 | free(line); | |
215 | fclose(f); | |
216 | return n; | |
217 | } | |
218 | ||
219 | int lxc_make_tmpfile(char *template, bool rm) | |
220 | { | |
221 | int fd, ret; | |
222 | mode_t msk; | |
223 | ||
224 | msk = umask(0022); | |
8f350e63 | 225 | fd = mkostemp(template, O_CLOEXEC); |
37ef15bb CB |
226 | umask(msk); |
227 | if (fd < 0) | |
228 | return -1; | |
229 | ||
230 | if (!rm) | |
231 | return fd; | |
232 | ||
233 | ret = unlink(template); | |
234 | if (ret < 0) { | |
235 | close(fd); | |
236 | return -1; | |
237 | } | |
238 | ||
239 | return fd; | |
240 | } | |
241 | ||
37ef15bb CB |
242 | bool is_fs_type(const struct statfs *fs, fs_type_magic magic_val) |
243 | { | |
244 | return (fs->f_type == (fs_type_magic)magic_val); | |
245 | } | |
246 | ||
247 | bool has_fs_type(const char *path, fs_type_magic magic_val) | |
248 | { | |
37ef15bb CB |
249 | int ret; |
250 | struct statfs sb; | |
251 | ||
252 | ret = statfs(path, &sb); | |
253 | if (ret < 0) | |
254 | return false; | |
255 | ||
256 | return is_fs_type(&sb, magic_val); | |
257 | } | |
258 | ||
259 | bool fhas_fs_type(int fd, fs_type_magic magic_val) | |
260 | { | |
261 | int ret; | |
262 | struct statfs sb; | |
263 | ||
264 | ret = fstatfs(fd, &sb); | |
265 | if (ret < 0) | |
266 | return false; | |
267 | ||
268 | return is_fs_type(&sb, magic_val); | |
269 | } | |
270 | ||
271 | FILE *fopen_cloexec(const char *path, const char *mode) | |
272 | { | |
273 | int open_mode = 0; | |
274 | int step = 0; | |
275 | int fd; | |
276 | int saved_errno = 0; | |
277 | FILE *ret; | |
278 | ||
279 | if (!strncmp(mode, "r+", 2)) { | |
280 | open_mode = O_RDWR; | |
281 | step = 2; | |
282 | } else if (!strncmp(mode, "r", 1)) { | |
283 | open_mode = O_RDONLY; | |
284 | step = 1; | |
285 | } else if (!strncmp(mode, "w+", 2)) { | |
286 | open_mode = O_RDWR | O_TRUNC | O_CREAT; | |
287 | step = 2; | |
288 | } else if (!strncmp(mode, "w", 1)) { | |
289 | open_mode = O_WRONLY | O_TRUNC | O_CREAT; | |
290 | step = 1; | |
291 | } else if (!strncmp(mode, "a+", 2)) { | |
292 | open_mode = O_RDWR | O_CREAT | O_APPEND; | |
293 | step = 2; | |
294 | } else if (!strncmp(mode, "a", 1)) { | |
295 | open_mode = O_WRONLY | O_CREAT | O_APPEND; | |
296 | step = 1; | |
297 | } | |
298 | for (; mode[step]; step++) | |
299 | if (mode[step] == 'x') | |
300 | open_mode |= O_EXCL; | |
301 | open_mode |= O_CLOEXEC; | |
302 | ||
3e9bde7e | 303 | fd = open(path, open_mode, 0660); |
37ef15bb CB |
304 | if (fd < 0) |
305 | return NULL; | |
306 | ||
307 | ret = fdopen(fd, mode); | |
308 | saved_errno = errno; | |
309 | if (!ret) | |
310 | close(fd); | |
311 | errno = saved_errno; | |
312 | return ret; | |
313 | } | |
7c4d9466 CB |
314 | |
315 | ssize_t lxc_sendfile_nointr(int out_fd, int in_fd, off_t *offset, size_t count) | |
316 | { | |
317 | ssize_t ret; | |
318 | ||
319 | again: | |
320 | ret = sendfile(out_fd, in_fd, offset, count); | |
321 | if (ret < 0) { | |
322 | if (errno == EINTR) | |
323 | goto again; | |
324 | ||
325 | return -1; | |
326 | } | |
327 | ||
328 | return ret; | |
329 | } | |
6400238d CB |
330 | |
331 | char *file_to_buf(char *path, size_t *length) | |
332 | { | |
333 | int fd; | |
334 | char buf[PATH_MAX]; | |
335 | char *copy = NULL; | |
336 | ||
337 | if (!length) | |
338 | return NULL; | |
339 | ||
340 | fd = open(path, O_RDONLY | O_CLOEXEC); | |
341 | if (fd < 0) | |
342 | return NULL; | |
343 | ||
344 | *length = 0; | |
345 | for (;;) { | |
346 | int n; | |
347 | char *old = copy; | |
348 | ||
349 | n = lxc_read_nointr(fd, buf, sizeof(buf)); | |
350 | if (n < 0) | |
351 | goto on_error; | |
352 | if (!n) | |
353 | break; | |
354 | ||
355 | copy = must_realloc(old, (*length + n) * sizeof(*old)); | |
356 | memcpy(copy + *length, buf, n); | |
357 | *length += n; | |
358 | } | |
359 | ||
360 | close(fd); | |
361 | return copy; | |
362 | ||
363 | on_error: | |
364 | close(fd); | |
365 | free(copy); | |
366 | ||
367 | return NULL; | |
368 | } | |
8f350e63 CB |
369 | |
370 | int fd_to_fd(int from, int to) | |
371 | { | |
372 | for (;;) { | |
373 | uint8_t buf[PATH_MAX]; | |
374 | uint8_t *p = buf; | |
375 | ssize_t bytes_to_write; | |
376 | ssize_t bytes_read; | |
377 | ||
378 | bytes_read = lxc_read_nointr(from, buf, sizeof buf); | |
379 | if (bytes_read < 0) | |
380 | return -1; | |
381 | if (bytes_read == 0) | |
382 | break; | |
383 | ||
384 | bytes_to_write = (size_t)bytes_read; | |
385 | do { | |
386 | ssize_t bytes_written; | |
387 | ||
388 | bytes_written = lxc_write_nointr(to, p, bytes_to_write); | |
389 | if (bytes_written < 0) | |
390 | return -1; | |
391 | ||
392 | bytes_to_write -= bytes_written; | |
393 | p += bytes_written; | |
394 | } while (bytes_to_write > 0); | |
395 | } | |
396 | ||
397 | return 0; | |
398 | } |