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/stat.h>
 28 74b37681 2019-02-07 stsp 
 29 74b37681 2019-02-07 stsp #include <errno.h>
 30 74b37681 2019-02-07 stsp #include <fcntl.h>
 31 74b37681 2019-02-07 stsp #include <stdint.h>
 32 74b37681 2019-02-07 stsp #include <stdio.h>
 33 74b37681 2019-02-07 stsp #include <stdlib.h>
 34 74b37681 2019-02-07 stsp #include <string.h>
 35 74b37681 2019-02-07 stsp #include <unistd.h>
 36 74b37681 2019-02-07 stsp 
 37 74b37681 2019-02-07 stsp #include "buf.h"
 38 74b37681 2019-02-07 stsp 
 39 af45e626 2019-02-08 stsp #include "got_error.h"
 40 af45e626 2019-02-08 stsp 
 41 74b37681 2019-02-07 stsp #define BUF_INCR	128
 42 74b37681 2019-02-07 stsp 
 43 575e8218 2019-10-07 stsp #define SIZE_LEFT(b)	((b)->cb_size - (b)->cb_len)
 44 74b37681 2019-02-07 stsp 
 45 af45e626 2019-02-08 stsp static const struct got_error *buf_grow(BUF *, size_t);
 46 74b37681 2019-02-07 stsp 
 47 74b37681 2019-02-07 stsp /*
 48 74b37681 2019-02-07 stsp  * Create a new buffer structure and return a pointer to it.  This structure
 49 74b37681 2019-02-07 stsp  * uses dynamically-allocated memory and must be freed with buf_free(), once
 50 74b37681 2019-02-07 stsp  * the buffer is no longer needed.
 51 74b37681 2019-02-07 stsp  */
 52 575e8218 2019-10-07 stsp const struct got_error *
 53 575e8218 2019-10-07 stsp buf_alloc(BUF **b, size_t len)
 54 74b37681 2019-02-07 stsp {
 55 575e8218 2019-10-07 stsp 	const struct got_error *err = NULL;
 56 74b37681 2019-02-07 stsp 
 57 575e8218 2019-10-07 stsp 	*b = malloc(sizeof(**b));
 58 575e8218 2019-10-07 stsp 	if (*b == NULL)
 59 af45e626 2019-02-08 stsp 		return NULL;
 60 74b37681 2019-02-07 stsp 	/* Postpone creation of zero-sized buffers */
 61 af45e626 2019-02-08 stsp 	if (len > 0) {
 62 575e8218 2019-10-07 stsp 		(*b)->cb_buf = calloc(1, len);
 63 575e8218 2019-10-07 stsp 		if ((*b)->cb_buf == NULL) {
 64 575e8218 2019-10-07 stsp 			err = got_error_from_errno("calloc");
 65 575e8218 2019-10-07 stsp 			free(*b);
 66 575e8218 2019-10-07 stsp 			*b = NULL;
 67 575e8218 2019-10-07 stsp 			return err;
 68 57ebf19f 2019-08-28 hiltjo 		}
 69 af45e626 2019-02-08 stsp 	} else
 70 575e8218 2019-10-07 stsp 		(*b)->cb_buf = NULL;
 71 74b37681 2019-02-07 stsp 
 72 575e8218 2019-10-07 stsp 	(*b)->cb_size = len;
 73 575e8218 2019-10-07 stsp 	(*b)->cb_len = 0;
 74 74b37681 2019-02-07 stsp 
 75 575e8218 2019-10-07 stsp 	return NULL;
 76 74b37681 2019-02-07 stsp }
 77 74b37681 2019-02-07 stsp 
 78 74b37681 2019-02-07 stsp /*
 79 74b37681 2019-02-07 stsp  * Open the file specified by <path> and load all of its contents into a
 80 74b37681 2019-02-07 stsp  * buffer.
 81 74b37681 2019-02-07 stsp  * Returns the loaded buffer on success or NULL on failure.
 82 74b37681 2019-02-07 stsp  * Sets errno on error.
 83 74b37681 2019-02-07 stsp  */
 84 575e8218 2019-10-07 stsp const struct got_error *
 85 db590691 2021-06-02 stsp buf_load(BUF **buf, FILE *f)
 86 74b37681 2019-02-07 stsp {
 87 575e8218 2019-10-07 stsp 	const struct got_error *err = NULL;
 88 db590691 2021-06-02 stsp 	size_t ret;
 89 74b37681 2019-02-07 stsp 	size_t len;
 90 74b37681 2019-02-07 stsp 	u_char *bp;
 91 74b37681 2019-02-07 stsp 	struct stat st;
 92 74b37681 2019-02-07 stsp 
 93 575e8218 2019-10-07 stsp 	*buf = NULL;
 94 74b37681 2019-02-07 stsp 
 95 db590691 2021-06-02 stsp 	if (fstat(fileno(f), &st) == -1) {
 96 db590691 2021-06-02 stsp 		err = got_error_from_errno("fstat");
 97 74b37681 2019-02-07 stsp 		goto out;
 98 575e8218 2019-10-07 stsp 	}
 99 74b37681 2019-02-07 stsp 
100 74b37681 2019-02-07 stsp 	if ((uintmax_t)st.st_size > SIZE_MAX) {
101 db590691 2021-06-02 stsp 		err = got_error_set_errno(EFBIG,
102 db590691 2021-06-02 stsp 		    "cannot fit file into memory buffer");
103 74b37681 2019-02-07 stsp 		goto out;
104 74b37681 2019-02-07 stsp 	}
105 575e8218 2019-10-07 stsp 	err = buf_alloc(buf, st.st_size);
106 575e8218 2019-10-07 stsp 	if (err)
107 575e8218 2019-10-07 stsp 		goto out;
108 db590691 2021-06-02 stsp 	for (bp = (*buf)->cb_buf; ; bp += ret) {
109 575e8218 2019-10-07 stsp 		len = SIZE_LEFT(*buf);
110 db590691 2021-06-02 stsp 		ret = fread(bp, 1, len, f);
111 db590691 2021-06-02 stsp 		if (ret == 0 && ferror(f)) {
112 db590691 2021-06-02 stsp 			err = got_ferror(f, GOT_ERR_IO);
113 74b37681 2019-02-07 stsp 			goto out;
114 74b37681 2019-02-07 stsp 		} else if (ret == 0)
115 74b37681 2019-02-07 stsp 			break;
116 74b37681 2019-02-07 stsp 
117 575e8218 2019-10-07 stsp 		(*buf)->cb_len += (size_t)ret;
118 74b37681 2019-02-07 stsp 	}
119 74b37681 2019-02-07 stsp 
120 74b37681 2019-02-07 stsp out:
121 575e8218 2019-10-07 stsp 	if (err) {
122 575e8218 2019-10-07 stsp 		buf_free(*buf);
123 575e8218 2019-10-07 stsp 		*buf = NULL;
124 74b37681 2019-02-07 stsp 	}
125 575e8218 2019-10-07 stsp 	return err;
126 74b37681 2019-02-07 stsp }
127 74b37681 2019-02-07 stsp 
128 74b37681 2019-02-07 stsp void
129 74b37681 2019-02-07 stsp buf_free(BUF *b)
130 74b37681 2019-02-07 stsp {
131 74b37681 2019-02-07 stsp 	if (b == NULL)
132 74b37681 2019-02-07 stsp 		return;
133 74b37681 2019-02-07 stsp 	free(b->cb_buf);
134 74b37681 2019-02-07 stsp 	free(b);
135 74b37681 2019-02-07 stsp }
136 74b37681 2019-02-07 stsp 
137 74b37681 2019-02-07 stsp /*
138 74b37681 2019-02-07 stsp  * Free the buffer <b>'s structural information but do not free the contents
139 74b37681 2019-02-07 stsp  * of the buffer.  Instead, they are returned and should be freed later using
140 74b37681 2019-02-07 stsp  * free().
141 74b37681 2019-02-07 stsp  */
142 74b37681 2019-02-07 stsp void *
143 74b37681 2019-02-07 stsp buf_release(BUF *b)
144 74b37681 2019-02-07 stsp {
145 74b37681 2019-02-07 stsp 	void *tmp;
146 74b37681 2019-02-07 stsp 
147 74b37681 2019-02-07 stsp 	tmp = b->cb_buf;
148 74b37681 2019-02-07 stsp 	free(b);
149 74b37681 2019-02-07 stsp 	return (tmp);
150 74b37681 2019-02-07 stsp }
151 74b37681 2019-02-07 stsp 
152 74b37681 2019-02-07 stsp u_char *
153 74b37681 2019-02-07 stsp buf_get(BUF *b)
154 74b37681 2019-02-07 stsp {
155 74b37681 2019-02-07 stsp 	return (b->cb_buf);
156 74b37681 2019-02-07 stsp }
157 74b37681 2019-02-07 stsp 
158 74b37681 2019-02-07 stsp /*
159 74b37681 2019-02-07 stsp  * Empty the contents of the buffer <b> and reset pointers.
160 74b37681 2019-02-07 stsp  */
161 74b37681 2019-02-07 stsp void
162 74b37681 2019-02-07 stsp buf_empty(BUF *b)
163 74b37681 2019-02-07 stsp {
164 74b37681 2019-02-07 stsp 	memset(b->cb_buf, 0, b->cb_size);
165 74b37681 2019-02-07 stsp 	b->cb_len = 0;
166 74b37681 2019-02-07 stsp }
167 74b37681 2019-02-07 stsp 
168 74b37681 2019-02-07 stsp /*
169 74b37681 2019-02-07 stsp  * Append a single character <c> to the end of the buffer <b>.
170 74b37681 2019-02-07 stsp  */
171 af45e626 2019-02-08 stsp const struct got_error *
172 74b37681 2019-02-07 stsp buf_putc(BUF *b, int c)
173 74b37681 2019-02-07 stsp {
174 af45e626 2019-02-08 stsp 	const struct got_error *err = NULL;
175 74b37681 2019-02-07 stsp 	u_char *bp;
176 74b37681 2019-02-07 stsp 
177 af45e626 2019-02-08 stsp 	if (SIZE_LEFT(b) == 0) {
178 af45e626 2019-02-08 stsp 		err = buf_grow(b, BUF_INCR);
179 af45e626 2019-02-08 stsp 		if (err)
180 af45e626 2019-02-08 stsp 			return err;
181 af45e626 2019-02-08 stsp 	}
182 74b37681 2019-02-07 stsp 	bp = b->cb_buf + b->cb_len;
183 74b37681 2019-02-07 stsp 	*bp = (u_char)c;
184 74b37681 2019-02-07 stsp 	b->cb_len++;
185 af45e626 2019-02-08 stsp 	return NULL;
186 74b37681 2019-02-07 stsp }
187 74b37681 2019-02-07 stsp 
188 74b37681 2019-02-07 stsp /*
189 74b37681 2019-02-07 stsp  * Append a string <s> to the end of buffer <b>.
190 74b37681 2019-02-07 stsp  */
191 af45e626 2019-02-08 stsp const struct got_error *
192 af45e626 2019-02-08 stsp buf_puts(size_t *newlen, BUF *b, const char *str)
193 74b37681 2019-02-07 stsp {
194 af45e626 2019-02-08 stsp 	return buf_append(newlen, b, str, strlen(str));
195 74b37681 2019-02-07 stsp }
196 74b37681 2019-02-07 stsp 
197 74b37681 2019-02-07 stsp /*
198 74b37681 2019-02-07 stsp  * Return u_char at buffer position <pos>.
199 74b37681 2019-02-07 stsp  */
200 74b37681 2019-02-07 stsp u_char
201 74b37681 2019-02-07 stsp buf_getc(BUF *b, size_t pos)
202 74b37681 2019-02-07 stsp {
203 74b37681 2019-02-07 stsp 	return (b->cb_buf[pos]);
204 74b37681 2019-02-07 stsp }
205 74b37681 2019-02-07 stsp 
206 74b37681 2019-02-07 stsp /*
207 74b37681 2019-02-07 stsp  * Append <len> bytes of data pointed to by <data> to the buffer <b>.  If the
208 74b37681 2019-02-07 stsp  * buffer is too small to accept all data, it will get resized to an
209 74b37681 2019-02-07 stsp  * appropriate size to accept all data.
210 74b37681 2019-02-07 stsp  * Returns the number of bytes successfully appended to the buffer.
211 74b37681 2019-02-07 stsp  */
212 af45e626 2019-02-08 stsp const struct got_error *
213 af45e626 2019-02-08 stsp buf_append(size_t *newlen, BUF *b, const void *data, size_t len)
214 74b37681 2019-02-07 stsp {
215 af45e626 2019-02-08 stsp 	const struct got_error *err = NULL;
216 74b37681 2019-02-07 stsp 	size_t left, rlen;
217 74b37681 2019-02-07 stsp 	u_char *bp;
218 74b37681 2019-02-07 stsp 
219 74b37681 2019-02-07 stsp 	left = SIZE_LEFT(b);
220 74b37681 2019-02-07 stsp 	rlen = len;
221 74b37681 2019-02-07 stsp 
222 af45e626 2019-02-08 stsp 	if (left < len) {
223 af45e626 2019-02-08 stsp 		err = buf_grow(b, len - left);
224 af45e626 2019-02-08 stsp 		if (err)
225 af45e626 2019-02-08 stsp 			return err;
226 af45e626 2019-02-08 stsp 	}
227 74b37681 2019-02-07 stsp 	bp = b->cb_buf + b->cb_len;
228 74b37681 2019-02-07 stsp 	memcpy(bp, data, rlen);
229 74b37681 2019-02-07 stsp 	b->cb_len += rlen;
230 74b37681 2019-02-07 stsp 
231 af45e626 2019-02-08 stsp 	*newlen = rlen;
232 af45e626 2019-02-08 stsp 	return NULL;
233 74b37681 2019-02-07 stsp }
234 74b37681 2019-02-07 stsp 
235 74b37681 2019-02-07 stsp /*
236 74b37681 2019-02-07 stsp  * Returns the size of the buffer that is being used.
237 74b37681 2019-02-07 stsp  */
238 74b37681 2019-02-07 stsp size_t
239 74b37681 2019-02-07 stsp buf_len(BUF *b)
240 74b37681 2019-02-07 stsp {
241 74b37681 2019-02-07 stsp 	return (b->cb_len);
242 74b37681 2019-02-07 stsp }
243 74b37681 2019-02-07 stsp 
244 74b37681 2019-02-07 stsp /*
245 74b37681 2019-02-07 stsp  * Write the contents of the buffer <b> to the specified <fd>
246 74b37681 2019-02-07 stsp  */
247 74b37681 2019-02-07 stsp int
248 74b37681 2019-02-07 stsp buf_write_fd(BUF *b, int fd)
249 74b37681 2019-02-07 stsp {
250 74b37681 2019-02-07 stsp 	u_char *bp;
251 74b37681 2019-02-07 stsp 	size_t len;
252 74b37681 2019-02-07 stsp 	ssize_t ret;
253 74b37681 2019-02-07 stsp 
254 74b37681 2019-02-07 stsp 	len = b->cb_len;
255 74b37681 2019-02-07 stsp 	bp = b->cb_buf;
256 74b37681 2019-02-07 stsp 
257 74b37681 2019-02-07 stsp 	do {
258 74b37681 2019-02-07 stsp 		ret = write(fd, bp, len);
259 74b37681 2019-02-07 stsp 		if (ret == -1) {
260 74b37681 2019-02-07 stsp 			if (errno == EINTR || errno == EAGAIN)
261 74b37681 2019-02-07 stsp 				continue;
262 74b37681 2019-02-07 stsp 			return (-1);
263 74b37681 2019-02-07 stsp 		}
264 74b37681 2019-02-07 stsp 
265 74b37681 2019-02-07 stsp 		len -= (size_t)ret;
266 74b37681 2019-02-07 stsp 		bp += (size_t)ret;
267 74b37681 2019-02-07 stsp 	} while (len > 0);
268 74b37681 2019-02-07 stsp 
269 74b37681 2019-02-07 stsp 	return (0);
270 74b37681 2019-02-07 stsp }
271 74b37681 2019-02-07 stsp 
272 74b37681 2019-02-07 stsp /*
273 74b37681 2019-02-07 stsp  * Write the contents of the buffer <b> to the file whose path is given in
274 74b37681 2019-02-07 stsp  * <path>.  If the file does not exist, it is created with mode <mode>.
275 74b37681 2019-02-07 stsp  */
276 af45e626 2019-02-08 stsp const struct got_error *
277 74b37681 2019-02-07 stsp buf_write(BUF *b, const char *path, mode_t mode)
278 74b37681 2019-02-07 stsp {
279 af45e626 2019-02-08 stsp 	const struct got_error *err = NULL;
280 74b37681 2019-02-07 stsp 	int fd;
281 74b37681 2019-02-07 stsp  open:
282 74b37681 2019-02-07 stsp 	if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, mode)) == -1) {
283 202329ae 2019-08-11 stsp 		err = got_error_from_errno2("open", path);
284 74b37681 2019-02-07 stsp 		if (errno == EACCES && unlink(path) != -1)
285 74b37681 2019-02-07 stsp 			goto open;
286 74b37681 2019-02-07 stsp 		else
287 202329ae 2019-08-11 stsp 			return err;
288 74b37681 2019-02-07 stsp 	}
289 74b37681 2019-02-07 stsp 
290 74b37681 2019-02-07 stsp 	if (buf_write_fd(b, fd) == -1) {
291 638f9024 2019-05-13 stsp 		err = got_error_from_errno("buf_write_fd");
292 74b37681 2019-02-07 stsp 		(void)unlink(path);
293 af45e626 2019-02-08 stsp 		return err;
294 74b37681 2019-02-07 stsp 	}
295 74b37681 2019-02-07 stsp 
296 74b37681 2019-02-07 stsp 	if (fchmod(fd, mode) < 0)
297 638f9024 2019-05-13 stsp 		err = got_error_from_errno2("fchmod", path);
298 74b37681 2019-02-07 stsp 
299 08578a35 2021-01-22 stsp 	if (close(fd) == -1 && err == NULL)
300 638f9024 2019-05-13 stsp 		err = got_error_from_errno2("close", path);
301 74b37681 2019-02-07 stsp 
302 af45e626 2019-02-08 stsp 	return err;
303 74b37681 2019-02-07 stsp }
304 74b37681 2019-02-07 stsp 
305 74b37681 2019-02-07 stsp /*
306 74b37681 2019-02-07 stsp  * Write the contents of the buffer <b> to a temporary file whose path is
307 74b37681 2019-02-07 stsp  * specified using <template> (see mkstemp.3).
308 74b37681 2019-02-07 stsp  * NB. This function will modify <template>, as per mkstemp
309 74b37681 2019-02-07 stsp  */
310 af45e626 2019-02-08 stsp const struct got_error *
311 96cbb597 2019-10-09 stsp buf_write_stmp(BUF *b, char *template)
312 74b37681 2019-02-07 stsp {
313 af45e626 2019-02-08 stsp 	const struct got_error *err = NULL;
314 74b37681 2019-02-07 stsp 	int fd;
315 74b37681 2019-02-07 stsp 
316 74b37681 2019-02-07 stsp 	if ((fd = mkstemp(template)) == -1)
317 638f9024 2019-05-13 stsp 		return got_error_from_errno("mkstemp");
318 74b37681 2019-02-07 stsp 
319 74b37681 2019-02-07 stsp 	if (buf_write_fd(b, fd) == -1) {
320 638f9024 2019-05-13 stsp 		err = got_error_from_errno("buf_write_fd");
321 74b37681 2019-02-07 stsp 		(void)unlink(template);
322 74b37681 2019-02-07 stsp 	}
323 74b37681 2019-02-07 stsp 
324 08578a35 2021-01-22 stsp 	if (close(fd) == -1 && err == NULL)
325 638f9024 2019-05-13 stsp 		err = got_error_from_errno("close");
326 3a6ce05a 2019-02-11 stsp 
327 af45e626 2019-02-08 stsp 	return err;
328 74b37681 2019-02-07 stsp }
329 74b37681 2019-02-07 stsp 
330 74b37681 2019-02-07 stsp /*
331 74b37681 2019-02-07 stsp  * Grow the buffer <b> by <len> bytes.  The contents are unchanged by this
332 74b37681 2019-02-07 stsp  * operation regardless of the result.
333 74b37681 2019-02-07 stsp  */
334 af45e626 2019-02-08 stsp static const struct got_error *
335 74b37681 2019-02-07 stsp buf_grow(BUF *b, size_t len)
336 74b37681 2019-02-07 stsp {
337 af45e626 2019-02-08 stsp 	u_char *buf;
338 af45e626 2019-02-08 stsp 	buf = reallocarray(b->cb_buf, 1, b->cb_size + len);
339 af45e626 2019-02-08 stsp 	if (buf == NULL)
340 638f9024 2019-05-13 stsp 		return got_error_from_errno("reallocarray");
341 af45e626 2019-02-08 stsp 	b->cb_buf = buf;
342 74b37681 2019-02-07 stsp 	b->cb_size += len;
343 af45e626 2019-02-08 stsp 	return NULL;
344 74b37681 2019-02-07 stsp }