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>
41 #include "got_error.h"
46 /* buffer handle, buffer size, and data length */
52 #define SIZE_LEFT(b) (b->cb_size - b->cb_len)
54 static const struct got_error *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 = malloc(sizeof(*b));
69 /* Postpone creation of zero-sized buffers */
71 b->cb_buf = calloc(1, len);
72 if (b->cb_buf == NULL)
84 * Open the file specified by <path> and load all of its contents into a
86 * Returns the loaded buffer on success or NULL on failure.
87 * Sets errno on error.
90 buf_load(const char *path)
101 if ((fd = open(path, O_RDONLY, 0600)) == -1)
104 if (fstat(fd, &st) == -1)
107 if ((uintmax_t)st.st_size > SIZE_MAX) {
111 buf = buf_alloc(st.st_size);
112 for (bp = buf->cb_buf; ; bp += (size_t)ret) {
113 len = SIZE_LEFT(buf);
114 ret = read(fd, bp, len);
126 buf->cb_len += (size_t)ret;
133 /* We may want to preserve errno here. */
152 * Free the buffer <b>'s structural information but do not free the contents
153 * of the buffer. Instead, they are returned and should be freed later using
173 * Empty the contents of the buffer <b> and reset pointers.
178 memset(b->cb_buf, 0, b->cb_size);
183 * Append a single character <c> to the end of the buffer <b>.
185 const struct got_error *
186 buf_putc(BUF *b, int c)
188 const struct got_error *err = NULL;
191 if (SIZE_LEFT(b) == 0) {
192 err = buf_grow(b, BUF_INCR);
196 bp = b->cb_buf + b->cb_len;
203 * Append a string <s> to the end of buffer <b>.
205 const struct got_error *
206 buf_puts(size_t *newlen, BUF *b, const char *str)
208 return buf_append(newlen, b, str, strlen(str));
212 * Return u_char at buffer position <pos>.
215 buf_getc(BUF *b, size_t pos)
217 return (b->cb_buf[pos]);
221 * Append <len> bytes of data pointed to by <data> to the buffer <b>. If the
222 * buffer is too small to accept all data, it will get resized to an
223 * appropriate size to accept all data.
224 * Returns the number of bytes successfully appended to the buffer.
226 const struct got_error *
227 buf_append(size_t *newlen, BUF *b, const void *data, size_t len)
229 const struct got_error *err = NULL;
237 err = buf_grow(b, len - left);
241 bp = b->cb_buf + b->cb_len;
242 memcpy(bp, data, rlen);
250 * Returns the size of the buffer that is being used.
259 * Write the contents of the buffer <b> to the specified <fd>
262 buf_write_fd(BUF *b, int fd)
272 ret = write(fd, bp, len);
274 if (errno == EINTR || errno == EAGAIN)
287 * Write the contents of the buffer <b> to the file whose path is given in
288 * <path>. If the file does not exist, it is created with mode <mode>.
290 const struct got_error *
291 buf_write(BUF *b, const char *path, mode_t mode)
293 const struct got_error *err = NULL;
296 if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, mode)) == -1) {
297 if (errno == EACCES && unlink(path) != -1)
300 return got_error_from_errno();
303 if (buf_write_fd(b, fd) == -1) {
304 err = got_error_from_errno();
309 if (fchmod(fd, mode) < 0)
310 err = got_error_from_errno();
312 if (close(fd) != 0 && err == NULL)
313 err = got_error_from_errno();
319 * Write the contents of the buffer <b> to a temporary file whose path is
320 * specified using <template> (see mkstemp.3).
321 * NB. This function will modify <template>, as per mkstemp
323 const struct got_error *
324 buf_write_stmp(BUF *b, char *template, struct wklhead *temp_files)
326 const struct got_error *err = NULL;
329 if ((fd = mkstemp(template)) == -1)
330 return got_error_from_errno();
332 worklist_add(template, temp_files);
334 if (buf_write_fd(b, fd) == -1) {
335 err = got_error_from_errno();
336 (void)unlink(template);
339 if (close(fd) != 0 && err == NULL)
340 err = got_error_from_errno();
346 * Grow the buffer <b> by <len> bytes. The contents are unchanged by this
347 * operation regardless of the result.
349 static const struct got_error *
350 buf_grow(BUF *b, size_t len)
353 buf = reallocarray(b->cb_buf, 1, b->cb_size + len);
355 return got_error_from_errno();