1 /* $OpenBSD: buf.c,v 1.27 2016/10/16 13:35:51 okan Exp $ */
3 * Copyright (c) 2003 Jean-Francois Brousseau <jfb@openbsd.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. The name of the author may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
15 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
16 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
17 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
18 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
21 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
23 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
24 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 #include <sys/queue.h>
40 #include "got_error.h"
44 #define SIZE_LEFT(b) ((b)->cb_size - (b)->cb_len)
46 static const struct got_error *buf_grow(BUF *, size_t);
49 * Create a new buffer structure and return a pointer to it. This structure
50 * uses dynamically-allocated memory and must be freed with buf_free(), once
51 * the buffer is no longer needed.
53 const struct got_error *
54 buf_alloc(BUF **b, size_t len)
56 const struct got_error *err = NULL;
58 *b = malloc(sizeof(**b));
61 /* Postpone creation of zero-sized buffers */
63 (*b)->cb_buf = calloc(1, len);
64 if ((*b)->cb_buf == NULL) {
65 err = got_error_from_errno("calloc");
80 * Open the file specified by <path> and load all of its contents into a
82 * Returns the loaded buffer on success or NULL on failure.
83 * Sets errno on error.
85 const struct got_error *
86 buf_load(BUF **buf, const char *path)
88 const struct got_error *err = NULL;
97 fd = open(path, O_RDONLY, 0600);
99 return got_error_from_errno2("open", path);
101 if (fstat(fd, &st) == -1) {
102 err = got_error_from_errno2("fstat", path);
106 if ((uintmax_t)st.st_size > SIZE_MAX) {
107 err = got_error_set_errno(EFBIG, path);
110 err = buf_alloc(buf, st.st_size);
113 for (bp = (*buf)->cb_buf; ; bp += (size_t)ret) {
114 len = SIZE_LEFT(*buf);
115 ret = read(fd, bp, len);
117 err = got_error_from_errno2("read", path);
122 (*buf)->cb_len += (size_t)ret;
126 if (close(fd) == -1 && err == NULL)
127 err = got_error_from_errno2("close", path);
145 * Free the buffer <b>'s structural information but do not free the contents
146 * of the buffer. Instead, they are returned and should be freed later using
166 * Empty the contents of the buffer <b> and reset pointers.
171 memset(b->cb_buf, 0, b->cb_size);
176 * Append a single character <c> to the end of the buffer <b>.
178 const struct got_error *
179 buf_putc(BUF *b, int c)
181 const struct got_error *err = NULL;
184 if (SIZE_LEFT(b) == 0) {
185 err = buf_grow(b, BUF_INCR);
189 bp = b->cb_buf + b->cb_len;
196 * Append a string <s> to the end of buffer <b>.
198 const struct got_error *
199 buf_puts(size_t *newlen, BUF *b, const char *str)
201 return buf_append(newlen, b, str, strlen(str));
205 * Return u_char at buffer position <pos>.
208 buf_getc(BUF *b, size_t pos)
210 return (b->cb_buf[pos]);
214 * Append <len> bytes of data pointed to by <data> to the buffer <b>. If the
215 * buffer is too small to accept all data, it will get resized to an
216 * appropriate size to accept all data.
217 * Returns the number of bytes successfully appended to the buffer.
219 const struct got_error *
220 buf_append(size_t *newlen, BUF *b, const void *data, size_t len)
222 const struct got_error *err = NULL;
230 err = buf_grow(b, len - left);
234 bp = b->cb_buf + b->cb_len;
235 memcpy(bp, data, rlen);
243 * Returns the size of the buffer that is being used.
252 * Write the contents of the buffer <b> to the specified <fd>
255 buf_write_fd(BUF *b, int fd)
265 ret = write(fd, bp, len);
267 if (errno == EINTR || errno == EAGAIN)
280 * Write the contents of the buffer <b> to the file whose path is given in
281 * <path>. If the file does not exist, it is created with mode <mode>.
283 const struct got_error *
284 buf_write(BUF *b, const char *path, mode_t mode)
286 const struct got_error *err = NULL;
289 if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, mode)) == -1) {
290 err = got_error_from_errno2("open", path);
291 if (errno == EACCES && unlink(path) != -1)
297 if (buf_write_fd(b, fd) == -1) {
298 err = got_error_from_errno("buf_write_fd");
303 if (fchmod(fd, mode) < 0)
304 err = got_error_from_errno2("fchmod", path);
306 if (close(fd) != 0 && err == NULL)
307 err = got_error_from_errno2("close", path);
313 * Write the contents of the buffer <b> to a temporary file whose path is
314 * specified using <template> (see mkstemp.3).
315 * NB. This function will modify <template>, as per mkstemp
317 const struct got_error *
318 buf_write_stmp(BUF *b, char *template)
320 const struct got_error *err = NULL;
323 if ((fd = mkstemp(template)) == -1)
324 return got_error_from_errno("mkstemp");
326 if (buf_write_fd(b, fd) == -1) {
327 err = got_error_from_errno("buf_write_fd");
328 (void)unlink(template);
331 if (close(fd) != 0 && err == NULL)
332 err = got_error_from_errno("close");
338 * Grow the buffer <b> by <len> bytes. The contents are unchanged by this
339 * operation regardless of the result.
341 static const struct got_error *
342 buf_grow(BUF *b, size_t len)
345 buf = reallocarray(b->cb_buf, 1, b->cb_size + len);
347 return got_error_from_errno("reallocarray");