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1 74b37681 2019-02-07 stsp /* $OpenBSD: buf.c,v 1.27 2016/10/16 13:35:51 okan Exp $ */
2 74b37681 2019-02-07 stsp /*
3 74b37681 2019-02-07 stsp * Copyright (c) 2003 Jean-Francois Brousseau <jfb@openbsd.org>
4 74b37681 2019-02-07 stsp * All rights reserved.
5 74b37681 2019-02-07 stsp *
6 74b37681 2019-02-07 stsp * Redistribution and use in source and binary forms, with or without
7 74b37681 2019-02-07 stsp * modification, are permitted provided that the following conditions
8 74b37681 2019-02-07 stsp * are met:
9 74b37681 2019-02-07 stsp *
10 74b37681 2019-02-07 stsp * 1. Redistributions of source code must retain the above copyright
11 74b37681 2019-02-07 stsp * notice, this list of conditions and the following disclaimer.
12 74b37681 2019-02-07 stsp * 2. The name of the author may not be used to endorse or promote products
13 74b37681 2019-02-07 stsp * derived from this software without specific prior written permission.
14 74b37681 2019-02-07 stsp *
15 74b37681 2019-02-07 stsp * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
16 74b37681 2019-02-07 stsp * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
17 74b37681 2019-02-07 stsp * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
18 74b37681 2019-02-07 stsp * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 74b37681 2019-02-07 stsp * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 74b37681 2019-02-07 stsp * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
21 74b37681 2019-02-07 stsp * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22 74b37681 2019-02-07 stsp * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
23 74b37681 2019-02-07 stsp * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
24 74b37681 2019-02-07 stsp * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 74b37681 2019-02-07 stsp */
26 74b37681 2019-02-07 stsp
27 74b37681 2019-02-07 stsp #include <sys/queue.h>
28 74b37681 2019-02-07 stsp #include <sys/stat.h>
29 74b37681 2019-02-07 stsp
30 74b37681 2019-02-07 stsp #include <errno.h>
31 74b37681 2019-02-07 stsp #include <fcntl.h>
32 74b37681 2019-02-07 stsp #include <stdint.h>
33 74b37681 2019-02-07 stsp #include <stdio.h>
34 74b37681 2019-02-07 stsp #include <stdlib.h>
35 74b37681 2019-02-07 stsp #include <string.h>
36 74b37681 2019-02-07 stsp #include <unistd.h>
37 74b37681 2019-02-07 stsp
38 74b37681 2019-02-07 stsp #include "buf.h"
39 74b37681 2019-02-07 stsp
40 af45e626 2019-02-08 stsp #include "got_error.h"
41 af45e626 2019-02-08 stsp
42 74b37681 2019-02-07 stsp #define BUF_INCR 128
43 74b37681 2019-02-07 stsp
44 74b37681 2019-02-07 stsp struct buf {
45 74b37681 2019-02-07 stsp /* buffer handle, buffer size, and data length */
46 74b37681 2019-02-07 stsp u_char *cb_buf;
47 74b37681 2019-02-07 stsp size_t cb_size;
48 74b37681 2019-02-07 stsp size_t cb_len;
49 74b37681 2019-02-07 stsp };
50 74b37681 2019-02-07 stsp
51 575e8218 2019-10-07 stsp #define SIZE_LEFT(b) ((b)->cb_size - (b)->cb_len)
52 74b37681 2019-02-07 stsp
53 af45e626 2019-02-08 stsp static const struct got_error *buf_grow(BUF *, size_t);
54 74b37681 2019-02-07 stsp
55 74b37681 2019-02-07 stsp /*
56 74b37681 2019-02-07 stsp * Create a new buffer structure and return a pointer to it. This structure
57 74b37681 2019-02-07 stsp * uses dynamically-allocated memory and must be freed with buf_free(), once
58 74b37681 2019-02-07 stsp * the buffer is no longer needed.
59 74b37681 2019-02-07 stsp */
60 575e8218 2019-10-07 stsp const struct got_error *
61 575e8218 2019-10-07 stsp buf_alloc(BUF **b, size_t len)
62 74b37681 2019-02-07 stsp {
63 575e8218 2019-10-07 stsp const struct got_error *err = NULL;
64 74b37681 2019-02-07 stsp
65 575e8218 2019-10-07 stsp *b = malloc(sizeof(**b));
66 575e8218 2019-10-07 stsp if (*b == NULL)
67 af45e626 2019-02-08 stsp return NULL;
68 74b37681 2019-02-07 stsp /* Postpone creation of zero-sized buffers */
69 af45e626 2019-02-08 stsp if (len > 0) {
70 575e8218 2019-10-07 stsp (*b)->cb_buf = calloc(1, len);
71 575e8218 2019-10-07 stsp if ((*b)->cb_buf == NULL) {
72 575e8218 2019-10-07 stsp err = got_error_from_errno("calloc");
73 575e8218 2019-10-07 stsp free(*b);
74 575e8218 2019-10-07 stsp *b = NULL;
75 575e8218 2019-10-07 stsp return err;
76 57ebf19f 2019-08-28 hiltjo }
77 af45e626 2019-02-08 stsp } else
78 575e8218 2019-10-07 stsp (*b)->cb_buf = NULL;
79 74b37681 2019-02-07 stsp
80 575e8218 2019-10-07 stsp (*b)->cb_size = len;
81 575e8218 2019-10-07 stsp (*b)->cb_len = 0;
82 74b37681 2019-02-07 stsp
83 575e8218 2019-10-07 stsp return NULL;
84 74b37681 2019-02-07 stsp }
85 74b37681 2019-02-07 stsp
86 74b37681 2019-02-07 stsp /*
87 74b37681 2019-02-07 stsp * Open the file specified by <path> and load all of its contents into a
88 74b37681 2019-02-07 stsp * buffer.
89 74b37681 2019-02-07 stsp * Returns the loaded buffer on success or NULL on failure.
90 74b37681 2019-02-07 stsp * Sets errno on error.
91 74b37681 2019-02-07 stsp */
92 575e8218 2019-10-07 stsp const struct got_error *
93 575e8218 2019-10-07 stsp buf_load(BUF **buf, const char *path)
94 74b37681 2019-02-07 stsp {
95 575e8218 2019-10-07 stsp const struct got_error *err = NULL;
96 74b37681 2019-02-07 stsp int fd;
97 74b37681 2019-02-07 stsp ssize_t ret;
98 74b37681 2019-02-07 stsp size_t len;
99 74b37681 2019-02-07 stsp u_char *bp;
100 74b37681 2019-02-07 stsp struct stat st;
101 74b37681 2019-02-07 stsp
102 575e8218 2019-10-07 stsp *buf = NULL;
103 74b37681 2019-02-07 stsp
104 575e8218 2019-10-07 stsp fd = open(path, O_RDONLY, 0600);
105 575e8218 2019-10-07 stsp if (fd == -1)
106 575e8218 2019-10-07 stsp return got_error_from_errno2("open", path);
107 74b37681 2019-02-07 stsp
108 575e8218 2019-10-07 stsp if (fstat(fd, &st) == -1) {
109 575e8218 2019-10-07 stsp err = got_error_from_errno2("fstat", path);
110 74b37681 2019-02-07 stsp goto out;
111 575e8218 2019-10-07 stsp }
112 74b37681 2019-02-07 stsp
113 74b37681 2019-02-07 stsp if ((uintmax_t)st.st_size > SIZE_MAX) {
114 575e8218 2019-10-07 stsp err = got_error_set_errno(EFBIG, path);
115 74b37681 2019-02-07 stsp goto out;
116 74b37681 2019-02-07 stsp }
117 575e8218 2019-10-07 stsp err = buf_alloc(buf, st.st_size);
118 575e8218 2019-10-07 stsp if (err)
119 575e8218 2019-10-07 stsp goto out;
120 575e8218 2019-10-07 stsp for (bp = (*buf)->cb_buf; ; bp += (size_t)ret) {
121 575e8218 2019-10-07 stsp len = SIZE_LEFT(*buf);
122 74b37681 2019-02-07 stsp ret = read(fd, bp, len);
123 74b37681 2019-02-07 stsp if (ret == -1) {
124 575e8218 2019-10-07 stsp err = got_error_from_errno2("read", path);
125 74b37681 2019-02-07 stsp goto out;
126 74b37681 2019-02-07 stsp } else if (ret == 0)
127 74b37681 2019-02-07 stsp break;
128 74b37681 2019-02-07 stsp
129 575e8218 2019-10-07 stsp (*buf)->cb_len += (size_t)ret;
130 74b37681 2019-02-07 stsp }
131 74b37681 2019-02-07 stsp
132 74b37681 2019-02-07 stsp out:
133 575e8218 2019-10-07 stsp if (close(fd) == -1 && err == NULL)
134 575e8218 2019-10-07 stsp err = got_error_from_errno2("close", path);
135 575e8218 2019-10-07 stsp if (err) {
136 575e8218 2019-10-07 stsp buf_free(*buf);
137 575e8218 2019-10-07 stsp *buf = NULL;
138 74b37681 2019-02-07 stsp }
139 575e8218 2019-10-07 stsp return err;
140 74b37681 2019-02-07 stsp }
141 74b37681 2019-02-07 stsp
142 74b37681 2019-02-07 stsp void
143 74b37681 2019-02-07 stsp buf_free(BUF *b)
144 74b37681 2019-02-07 stsp {
145 74b37681 2019-02-07 stsp if (b == NULL)
146 74b37681 2019-02-07 stsp return;
147 74b37681 2019-02-07 stsp free(b->cb_buf);
148 74b37681 2019-02-07 stsp free(b);
149 74b37681 2019-02-07 stsp }
150 74b37681 2019-02-07 stsp
151 74b37681 2019-02-07 stsp /*
152 74b37681 2019-02-07 stsp * Free the buffer <b>'s structural information but do not free the contents
153 74b37681 2019-02-07 stsp * of the buffer. Instead, they are returned and should be freed later using
154 74b37681 2019-02-07 stsp * free().
155 74b37681 2019-02-07 stsp */
156 74b37681 2019-02-07 stsp void *
157 74b37681 2019-02-07 stsp buf_release(BUF *b)
158 74b37681 2019-02-07 stsp {
159 74b37681 2019-02-07 stsp void *tmp;
160 74b37681 2019-02-07 stsp
161 74b37681 2019-02-07 stsp tmp = b->cb_buf;
162 74b37681 2019-02-07 stsp free(b);
163 74b37681 2019-02-07 stsp return (tmp);
164 74b37681 2019-02-07 stsp }
165 74b37681 2019-02-07 stsp
166 74b37681 2019-02-07 stsp u_char *
167 74b37681 2019-02-07 stsp buf_get(BUF *b)
168 74b37681 2019-02-07 stsp {
169 74b37681 2019-02-07 stsp return (b->cb_buf);
170 74b37681 2019-02-07 stsp }
171 74b37681 2019-02-07 stsp
172 74b37681 2019-02-07 stsp /*
173 74b37681 2019-02-07 stsp * Empty the contents of the buffer <b> and reset pointers.
174 74b37681 2019-02-07 stsp */
175 74b37681 2019-02-07 stsp void
176 74b37681 2019-02-07 stsp buf_empty(BUF *b)
177 74b37681 2019-02-07 stsp {
178 74b37681 2019-02-07 stsp memset(b->cb_buf, 0, b->cb_size);
179 74b37681 2019-02-07 stsp b->cb_len = 0;
180 74b37681 2019-02-07 stsp }
181 74b37681 2019-02-07 stsp
182 74b37681 2019-02-07 stsp /*
183 74b37681 2019-02-07 stsp * Append a single character <c> to the end of the buffer <b>.
184 74b37681 2019-02-07 stsp */
185 af45e626 2019-02-08 stsp const struct got_error *
186 74b37681 2019-02-07 stsp buf_putc(BUF *b, int c)
187 74b37681 2019-02-07 stsp {
188 af45e626 2019-02-08 stsp const struct got_error *err = NULL;
189 74b37681 2019-02-07 stsp u_char *bp;
190 74b37681 2019-02-07 stsp
191 af45e626 2019-02-08 stsp if (SIZE_LEFT(b) == 0) {
192 af45e626 2019-02-08 stsp err = buf_grow(b, BUF_INCR);
193 af45e626 2019-02-08 stsp if (err)
194 af45e626 2019-02-08 stsp return err;
195 af45e626 2019-02-08 stsp }
196 74b37681 2019-02-07 stsp bp = b->cb_buf + b->cb_len;
197 74b37681 2019-02-07 stsp *bp = (u_char)c;
198 74b37681 2019-02-07 stsp b->cb_len++;
199 af45e626 2019-02-08 stsp return NULL;
200 74b37681 2019-02-07 stsp }
201 74b37681 2019-02-07 stsp
202 74b37681 2019-02-07 stsp /*
203 74b37681 2019-02-07 stsp * Append a string <s> to the end of buffer <b>.
204 74b37681 2019-02-07 stsp */
205 af45e626 2019-02-08 stsp const struct got_error *
206 af45e626 2019-02-08 stsp buf_puts(size_t *newlen, BUF *b, const char *str)
207 74b37681 2019-02-07 stsp {
208 af45e626 2019-02-08 stsp return buf_append(newlen, b, str, strlen(str));
209 74b37681 2019-02-07 stsp }
210 74b37681 2019-02-07 stsp
211 74b37681 2019-02-07 stsp /*
212 74b37681 2019-02-07 stsp * Return u_char at buffer position <pos>.
213 74b37681 2019-02-07 stsp */
214 74b37681 2019-02-07 stsp u_char
215 74b37681 2019-02-07 stsp buf_getc(BUF *b, size_t pos)
216 74b37681 2019-02-07 stsp {
217 74b37681 2019-02-07 stsp return (b->cb_buf[pos]);
218 74b37681 2019-02-07 stsp }
219 74b37681 2019-02-07 stsp
220 74b37681 2019-02-07 stsp /*
221 74b37681 2019-02-07 stsp * Append <len> bytes of data pointed to by <data> to the buffer <b>. If the
222 74b37681 2019-02-07 stsp * buffer is too small to accept all data, it will get resized to an
223 74b37681 2019-02-07 stsp * appropriate size to accept all data.
224 74b37681 2019-02-07 stsp * Returns the number of bytes successfully appended to the buffer.
225 74b37681 2019-02-07 stsp */
226 af45e626 2019-02-08 stsp const struct got_error *
227 af45e626 2019-02-08 stsp buf_append(size_t *newlen, BUF *b, const void *data, size_t len)
228 74b37681 2019-02-07 stsp {
229 af45e626 2019-02-08 stsp const struct got_error *err = NULL;
230 74b37681 2019-02-07 stsp size_t left, rlen;
231 74b37681 2019-02-07 stsp u_char *bp;
232 74b37681 2019-02-07 stsp
233 74b37681 2019-02-07 stsp left = SIZE_LEFT(b);
234 74b37681 2019-02-07 stsp rlen = len;
235 74b37681 2019-02-07 stsp
236 af45e626 2019-02-08 stsp if (left < len) {
237 af45e626 2019-02-08 stsp err = buf_grow(b, len - left);
238 af45e626 2019-02-08 stsp if (err)
239 af45e626 2019-02-08 stsp return err;
240 af45e626 2019-02-08 stsp }
241 74b37681 2019-02-07 stsp bp = b->cb_buf + b->cb_len;
242 74b37681 2019-02-07 stsp memcpy(bp, data, rlen);
243 74b37681 2019-02-07 stsp b->cb_len += rlen;
244 74b37681 2019-02-07 stsp
245 af45e626 2019-02-08 stsp *newlen = rlen;
246 af45e626 2019-02-08 stsp return NULL;
247 74b37681 2019-02-07 stsp }
248 74b37681 2019-02-07 stsp
249 74b37681 2019-02-07 stsp /*
250 74b37681 2019-02-07 stsp * Returns the size of the buffer that is being used.
251 74b37681 2019-02-07 stsp */
252 74b37681 2019-02-07 stsp size_t
253 74b37681 2019-02-07 stsp buf_len(BUF *b)
254 74b37681 2019-02-07 stsp {
255 74b37681 2019-02-07 stsp return (b->cb_len);
256 74b37681 2019-02-07 stsp }
257 74b37681 2019-02-07 stsp
258 74b37681 2019-02-07 stsp /*
259 74b37681 2019-02-07 stsp * Write the contents of the buffer <b> to the specified <fd>
260 74b37681 2019-02-07 stsp */
261 74b37681 2019-02-07 stsp int
262 74b37681 2019-02-07 stsp buf_write_fd(BUF *b, int fd)
263 74b37681 2019-02-07 stsp {
264 74b37681 2019-02-07 stsp u_char *bp;
265 74b37681 2019-02-07 stsp size_t len;
266 74b37681 2019-02-07 stsp ssize_t ret;
267 74b37681 2019-02-07 stsp
268 74b37681 2019-02-07 stsp len = b->cb_len;
269 74b37681 2019-02-07 stsp bp = b->cb_buf;
270 74b37681 2019-02-07 stsp
271 74b37681 2019-02-07 stsp do {
272 74b37681 2019-02-07 stsp ret = write(fd, bp, len);
273 74b37681 2019-02-07 stsp if (ret == -1) {
274 74b37681 2019-02-07 stsp if (errno == EINTR || errno == EAGAIN)
275 74b37681 2019-02-07 stsp continue;
276 74b37681 2019-02-07 stsp return (-1);
277 74b37681 2019-02-07 stsp }
278 74b37681 2019-02-07 stsp
279 74b37681 2019-02-07 stsp len -= (size_t)ret;
280 74b37681 2019-02-07 stsp bp += (size_t)ret;
281 74b37681 2019-02-07 stsp } while (len > 0);
282 74b37681 2019-02-07 stsp
283 74b37681 2019-02-07 stsp return (0);
284 74b37681 2019-02-07 stsp }
285 74b37681 2019-02-07 stsp
286 74b37681 2019-02-07 stsp /*
287 74b37681 2019-02-07 stsp * Write the contents of the buffer <b> to the file whose path is given in
288 74b37681 2019-02-07 stsp * <path>. If the file does not exist, it is created with mode <mode>.
289 74b37681 2019-02-07 stsp */
290 af45e626 2019-02-08 stsp const struct got_error *
291 74b37681 2019-02-07 stsp buf_write(BUF *b, const char *path, mode_t mode)
292 74b37681 2019-02-07 stsp {
293 af45e626 2019-02-08 stsp const struct got_error *err = NULL;
294 74b37681 2019-02-07 stsp int fd;
295 74b37681 2019-02-07 stsp open:
296 74b37681 2019-02-07 stsp if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, mode)) == -1) {
297 202329ae 2019-08-11 stsp err = got_error_from_errno2("open", path);
298 74b37681 2019-02-07 stsp if (errno == EACCES && unlink(path) != -1)
299 74b37681 2019-02-07 stsp goto open;
300 74b37681 2019-02-07 stsp else
301 202329ae 2019-08-11 stsp return err;
302 74b37681 2019-02-07 stsp }
303 74b37681 2019-02-07 stsp
304 74b37681 2019-02-07 stsp if (buf_write_fd(b, fd) == -1) {
305 638f9024 2019-05-13 stsp err = got_error_from_errno("buf_write_fd");
306 74b37681 2019-02-07 stsp (void)unlink(path);
307 af45e626 2019-02-08 stsp return err;
308 74b37681 2019-02-07 stsp }
309 74b37681 2019-02-07 stsp
310 74b37681 2019-02-07 stsp if (fchmod(fd, mode) < 0)
311 638f9024 2019-05-13 stsp err = got_error_from_errno2("fchmod", path);
312 74b37681 2019-02-07 stsp
313 3a6ce05a 2019-02-11 stsp if (close(fd) != 0 && err == NULL)
314 638f9024 2019-05-13 stsp err = got_error_from_errno2("close", path);
315 74b37681 2019-02-07 stsp
316 af45e626 2019-02-08 stsp return err;
317 74b37681 2019-02-07 stsp }
318 74b37681 2019-02-07 stsp
319 74b37681 2019-02-07 stsp /*
320 74b37681 2019-02-07 stsp * Write the contents of the buffer <b> to a temporary file whose path is
321 74b37681 2019-02-07 stsp * specified using <template> (see mkstemp.3).
322 74b37681 2019-02-07 stsp * NB. This function will modify <template>, as per mkstemp
323 74b37681 2019-02-07 stsp */
324 af45e626 2019-02-08 stsp const struct got_error *
325 96cbb597 2019-10-09 stsp buf_write_stmp(BUF *b, char *template)
326 74b37681 2019-02-07 stsp {
327 af45e626 2019-02-08 stsp const struct got_error *err = NULL;
328 74b37681 2019-02-07 stsp int fd;
329 74b37681 2019-02-07 stsp
330 74b37681 2019-02-07 stsp if ((fd = mkstemp(template)) == -1)
331 638f9024 2019-05-13 stsp return got_error_from_errno("mkstemp");
332 74b37681 2019-02-07 stsp
333 74b37681 2019-02-07 stsp if (buf_write_fd(b, fd) == -1) {
334 638f9024 2019-05-13 stsp err = got_error_from_errno("buf_write_fd");
335 74b37681 2019-02-07 stsp (void)unlink(template);
336 74b37681 2019-02-07 stsp }
337 74b37681 2019-02-07 stsp
338 3a6ce05a 2019-02-11 stsp if (close(fd) != 0 && err == NULL)
339 638f9024 2019-05-13 stsp err = got_error_from_errno("close");
340 3a6ce05a 2019-02-11 stsp
341 af45e626 2019-02-08 stsp return err;
342 74b37681 2019-02-07 stsp }
343 74b37681 2019-02-07 stsp
344 74b37681 2019-02-07 stsp /*
345 74b37681 2019-02-07 stsp * Grow the buffer <b> by <len> bytes. The contents are unchanged by this
346 74b37681 2019-02-07 stsp * operation regardless of the result.
347 74b37681 2019-02-07 stsp */
348 af45e626 2019-02-08 stsp static const struct got_error *
349 74b37681 2019-02-07 stsp buf_grow(BUF *b, size_t len)
350 74b37681 2019-02-07 stsp {
351 af45e626 2019-02-08 stsp u_char *buf;
352 af45e626 2019-02-08 stsp buf = reallocarray(b->cb_buf, 1, b->cb_size + len);
353 af45e626 2019-02-08 stsp if (buf == NULL)
354 638f9024 2019-05-13 stsp return got_error_from_errno("reallocarray");
355 af45e626 2019-02-08 stsp b->cb_buf = buf;
356 74b37681 2019-02-07 stsp b->cb_size += len;
357 af45e626 2019-02-08 stsp return NULL;
358 74b37681 2019-02-07 stsp }