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));
60 return got_error_from_errno("malloc");
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, FILE *f)
88 const struct got_error *err = NULL;
96 if (fstat(fileno(f), &st) == -1) {
97 err = got_error_from_errno("fstat");
101 if ((uintmax_t)st.st_size > SIZE_MAX) {
102 err = got_error_set_errno(EFBIG,
103 "cannot fit file into memory buffer");
106 err = buf_alloc(buf, st.st_size);
109 for (bp = (*buf)->cb_buf; ; bp += ret) {
110 len = SIZE_LEFT(*buf);
111 ret = fread(bp, 1, len, f);
112 if (ret == 0 && ferror(f)) {
113 err = got_ferror(f, GOT_ERR_IO);
118 (*buf)->cb_len += (size_t)ret;
129 const struct got_error *
130 buf_load_fd(BUF **buf, int fd)
132 const struct got_error *err = NULL;
133 unsigned char out[8192];
137 err = buf_alloc(buf, 8192);
142 r = read(fd, out, sizeof(out));
144 return got_error_from_errno("read");
146 err = buf_append(&len, *buf, out, r);
165 * Free the buffer <b>'s structural information but do not free the contents
166 * of the buffer. Instead, they are returned and should be freed later using
186 * Empty the contents of the buffer <b> and reset pointers.
191 memset(b->cb_buf, 0, b->cb_size);
196 * Append a single character <c> to the end of the buffer <b>.
198 const struct got_error *
199 buf_putc(BUF *b, int c)
201 const struct got_error *err = NULL;
204 if (SIZE_LEFT(b) == 0) {
205 err = buf_grow(b, BUF_INCR);
209 bp = b->cb_buf + b->cb_len;
216 * Append a string <s> to the end of buffer <b>.
218 const struct got_error *
219 buf_puts(size_t *newlen, BUF *b, const char *str)
221 return buf_append(newlen, b, str, strlen(str));
225 * Return u_char at buffer position <pos>.
228 buf_getc(BUF *b, size_t pos)
230 return (b->cb_buf[pos]);
234 * Append <len> bytes of data pointed to by <data> to the buffer <b>. If the
235 * buffer is too small to accept all data, it will get resized to an
236 * appropriate size to accept all data.
237 * Returns the number of bytes successfully appended to the buffer.
239 const struct got_error *
240 buf_append(size_t *newlen, BUF *b, const void *data, size_t len)
242 const struct got_error *err = NULL;
250 err = buf_grow(b, len - left);
254 bp = b->cb_buf + b->cb_len;
255 memcpy(bp, data, rlen);
263 * Returns the size of the buffer that is being used.
272 * Write the contents of the buffer <b> to the specified <fd>
275 buf_write_fd(BUF *b, int fd)
285 ret = write(fd, bp, len);
287 if (errno == EINTR || errno == EAGAIN)
300 * Write the contents of the buffer <b> to the file whose path is given in
301 * <path>. If the file does not exist, it is created with mode <mode>.
303 const struct got_error *
304 buf_write(BUF *b, const char *path, mode_t mode)
306 const struct got_error *err = NULL;
309 if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, mode)) == -1) {
310 err = got_error_from_errno2("open", path);
311 if (errno == EACCES && unlink(path) != -1)
317 if (buf_write_fd(b, fd) == -1) {
318 err = got_error_from_errno("buf_write_fd");
323 if (fchmod(fd, mode) < 0)
324 err = got_error_from_errno2("fchmod", path);
326 if (close(fd) == -1 && err == NULL)
327 err = got_error_from_errno2("close", path);
333 * Write the contents of the buffer <b> to a temporary file whose path is
334 * specified using <template> (see mkstemp.3).
335 * NB. This function will modify <template>, as per mkstemp
337 const struct got_error *
338 buf_write_stmp(BUF *b, char *template)
340 const struct got_error *err = NULL;
343 if ((fd = mkstemp(template)) == -1)
344 return got_error_from_errno("mkstemp");
346 if (buf_write_fd(b, fd) == -1) {
347 err = got_error_from_errno("buf_write_fd");
348 (void)unlink(template);
351 if (close(fd) == -1 && err == NULL)
352 err = got_error_from_errno("close");
358 * Grow the buffer <b> by <len> bytes. The contents are unchanged by this
359 * operation regardless of the result.
361 static const struct got_error *
362 buf_grow(BUF *b, size_t len)
365 buf = reallocarray(b->cb_buf, 1, b->cb_size + len);
367 return got_error_from_errno("reallocarray");