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>
46 /* buffer handle, buffer size, and data length */
52 #define SIZE_LEFT(b) (b->cb_size - b->cb_len)
54 static void buf_grow(BUF *, size_t);
57 * Create a new buffer structure and return a pointer to it. This structure
58 * uses dynamically-allocated memory and must be freed with buf_free(), once
59 * the buffer is no longer needed.
66 b = xmalloc(sizeof(*b));
67 /* Postpone creation of zero-sized buffers */
69 b->cb_buf = xcalloc(1, len);
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.
86 buf_load(const char *path)
97 if ((fd = open(path, O_RDONLY, 0600)) == -1)
100 if (fstat(fd, &st) == -1)
103 if ((uintmax_t)st.st_size > SIZE_MAX) {
107 buf = buf_alloc(st.st_size);
108 for (bp = buf->cb_buf; ; bp += (size_t)ret) {
109 len = SIZE_LEFT(buf);
110 ret = read(fd, bp, len);
122 buf->cb_len += (size_t)ret;
129 /* We may want to preserve errno here. */
148 * Free the buffer <b>'s structural information but do not free the contents
149 * of the buffer. Instead, they are returned and should be freed later using
169 * Empty the contents of the buffer <b> and reset pointers.
174 memset(b->cb_buf, 0, b->cb_size);
179 * Append a single character <c> to the end of the buffer <b>.
182 buf_putc(BUF *b, int c)
186 if (SIZE_LEFT(b) == 0)
187 buf_grow(b, BUF_INCR);
188 bp = b->cb_buf + b->cb_len;
194 * Append a string <s> to the end of buffer <b>.
197 buf_puts(BUF *b, const char *str)
199 buf_append(b, str, strlen(str));
203 * Return u_char at buffer position <pos>.
206 buf_getc(BUF *b, size_t pos)
208 return (b->cb_buf[pos]);
212 * Append <len> bytes of data pointed to by <data> to the buffer <b>. If the
213 * buffer is too small to accept all data, it will get resized to an
214 * appropriate size to accept all data.
215 * Returns the number of bytes successfully appended to the buffer.
218 buf_append(BUF *b, const void *data, size_t len)
227 buf_grow(b, len - left);
228 bp = b->cb_buf + b->cb_len;
229 memcpy(bp, data, rlen);
236 * Returns the size of the buffer that is being used.
245 * Write the contents of the buffer <b> to the specified <fd>
248 buf_write_fd(BUF *b, int fd)
258 ret = write(fd, bp, len);
260 if (errno == EINTR || errno == EAGAIN)
273 * Write the contents of the buffer <b> to the file whose path is given in
274 * <path>. If the file does not exist, it is created with mode <mode>.
277 buf_write(BUF *b, const char *path, mode_t mode)
281 if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, mode)) == -1) {
282 if (errno == EACCES && unlink(path) != -1)
288 if (buf_write_fd(b, fd) == -1) {
290 errx(1, "buf_write: buf_write_fd: `%s'", path);
293 if (fchmod(fd, mode) < 0)
294 warn("permissions not set on file %s", path);
302 * Write the contents of the buffer <b> to a temporary file whose path is
303 * specified using <template> (see mkstemp.3).
304 * NB. This function will modify <template>, as per mkstemp
307 buf_write_stmp(BUF *b, char *template)
311 if ((fd = mkstemp(template)) == -1)
312 err(1, "%s", template);
314 worklist_add(template, &temp_files);
316 if (buf_write_fd(b, fd) == -1) {
317 (void)unlink(template);
318 errx(1, "buf_write_stmp: buf_write_fd: `%s'", template);
325 * Grow the buffer <b> by <len> bytes. The contents are unchanged by this
326 * operation regardless of the result.
329 buf_grow(BUF *b, size_t len)
331 b->cb_buf = xreallocarray(b->cb_buf, 1, b->cb_size + len);