/* $OpenBSD: buf.c,v 1.27 2016/10/16 13:35:51 okan Exp $ */
/*
* Copyright (c) 2003 Jean-Francois Brousseau <jfb@openbsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/queue.h>
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "buf.h"
#include "got_error.h"
#define BUF_INCR 128
#define SIZE_LEFT(b) ((b)->cb_size - (b)->cb_len)
static const struct got_error *buf_grow(BUF *, size_t);
/*
* Create a new buffer structure and return a pointer to it. This structure
* uses dynamically-allocated memory and must be freed with buf_free(), once
* the buffer is no longer needed.
*/
const struct got_error *
buf_alloc(BUF **b, size_t len)
{
const struct got_error *err = NULL;
*b = malloc(sizeof(**b));
if (*b == NULL)
return NULL;
/* Postpone creation of zero-sized buffers */
if (len > 0) {
(*b)->cb_buf = calloc(1, len);
if ((*b)->cb_buf == NULL) {
err = got_error_from_errno("calloc");
free(*b);
*b = NULL;
return err;
}
} else
(*b)->cb_buf = NULL;
(*b)->cb_size = len;
(*b)->cb_len = 0;
return NULL;
}
/*
* Open the file specified by <path> and load all of its contents into a
* buffer.
* Returns the loaded buffer on success or NULL on failure.
* Sets errno on error.
*/
const struct got_error *
buf_load(BUF **buf, const char *path)
{
const struct got_error *err = NULL;
int fd;
ssize_t ret;
size_t len;
u_char *bp;
struct stat st;
*buf = NULL;
fd = open(path, O_RDONLY, 0600);
if (fd == -1)
return got_error_from_errno2("open", path);
if (fstat(fd, &st) == -1) {
err = got_error_from_errno2("fstat", path);
goto out;
}
if ((uintmax_t)st.st_size > SIZE_MAX) {
err = got_error_set_errno(EFBIG, path);
goto out;
}
err = buf_alloc(buf, st.st_size);
if (err)
goto out;
for (bp = (*buf)->cb_buf; ; bp += (size_t)ret) {
len = SIZE_LEFT(*buf);
ret = read(fd, bp, len);
if (ret == -1) {
err = got_error_from_errno2("read", path);
goto out;
} else if (ret == 0)
break;
(*buf)->cb_len += (size_t)ret;
}
out:
if (close(fd) == -1 && err == NULL)
err = got_error_from_errno2("close", path);
if (err) {
buf_free(*buf);
*buf = NULL;
}
return err;
}
void
buf_free(BUF *b)
{
if (b == NULL)
return;
free(b->cb_buf);
free(b);
}
/*
* Free the buffer <b>'s structural information but do not free the contents
* of the buffer. Instead, they are returned and should be freed later using
* free().
*/
void *
buf_release(BUF *b)
{
void *tmp;
tmp = b->cb_buf;
free(b);
return (tmp);
}
u_char *
buf_get(BUF *b)
{
return (b->cb_buf);
}
/*
* Empty the contents of the buffer <b> and reset pointers.
*/
void
buf_empty(BUF *b)
{
memset(b->cb_buf, 0, b->cb_size);
b->cb_len = 0;
}
/*
* Append a single character <c> to the end of the buffer <b>.
*/
const struct got_error *
buf_putc(BUF *b, int c)
{
const struct got_error *err = NULL;
u_char *bp;
if (SIZE_LEFT(b) == 0) {
err = buf_grow(b, BUF_INCR);
if (err)
return err;
}
bp = b->cb_buf + b->cb_len;
*bp = (u_char)c;
b->cb_len++;
return NULL;
}
/*
* Append a string <s> to the end of buffer <b>.
*/
const struct got_error *
buf_puts(size_t *newlen, BUF *b, const char *str)
{
return buf_append(newlen, b, str, strlen(str));
}
/*
* Return u_char at buffer position <pos>.
*/
u_char
buf_getc(BUF *b, size_t pos)
{
return (b->cb_buf[pos]);
}
/*
* Append <len> bytes of data pointed to by <data> to the buffer <b>. If the
* buffer is too small to accept all data, it will get resized to an
* appropriate size to accept all data.
* Returns the number of bytes successfully appended to the buffer.
*/
const struct got_error *
buf_append(size_t *newlen, BUF *b, const void *data, size_t len)
{
const struct got_error *err = NULL;
size_t left, rlen;
u_char *bp;
left = SIZE_LEFT(b);
rlen = len;
if (left < len) {
err = buf_grow(b, len - left);
if (err)
return err;
}
bp = b->cb_buf + b->cb_len;
memcpy(bp, data, rlen);
b->cb_len += rlen;
*newlen = rlen;
return NULL;
}
/*
* Returns the size of the buffer that is being used.
*/
size_t
buf_len(BUF *b)
{
return (b->cb_len);
}
/*
* Write the contents of the buffer <b> to the specified <fd>
*/
int
buf_write_fd(BUF *b, int fd)
{
u_char *bp;
size_t len;
ssize_t ret;
len = b->cb_len;
bp = b->cb_buf;
do {
ret = write(fd, bp, len);
if (ret == -1) {
if (errno == EINTR || errno == EAGAIN)
continue;
return (-1);
}
len -= (size_t)ret;
bp += (size_t)ret;
} while (len > 0);
return (0);
}
/*
* Write the contents of the buffer <b> to the file whose path is given in
* <path>. If the file does not exist, it is created with mode <mode>.
*/
const struct got_error *
buf_write(BUF *b, const char *path, mode_t mode)
{
const struct got_error *err = NULL;
int fd;
open:
if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, mode)) == -1) {
err = got_error_from_errno2("open", path);
if (errno == EACCES && unlink(path) != -1)
goto open;
else
return err;
}
if (buf_write_fd(b, fd) == -1) {
err = got_error_from_errno("buf_write_fd");
(void)unlink(path);
return err;
}
if (fchmod(fd, mode) < 0)
err = got_error_from_errno2("fchmod", path);
if (close(fd) != 0 && err == NULL)
err = got_error_from_errno2("close", path);
return err;
}
/*
* Write the contents of the buffer <b> to a temporary file whose path is
* specified using <template> (see mkstemp.3).
* NB. This function will modify <template>, as per mkstemp
*/
const struct got_error *
buf_write_stmp(BUF *b, char *template)
{
const struct got_error *err = NULL;
int fd;
if ((fd = mkstemp(template)) == -1)
return got_error_from_errno("mkstemp");
if (buf_write_fd(b, fd) == -1) {
err = got_error_from_errno("buf_write_fd");
(void)unlink(template);
}
if (close(fd) != 0 && err == NULL)
err = got_error_from_errno("close");
return err;
}
/*
* Grow the buffer <b> by <len> bytes. The contents are unchanged by this
* operation regardless of the result.
*/
static const struct got_error *
buf_grow(BUF *b, size_t len)
{
u_char *buf;
buf = reallocarray(b->cb_buf, 1, b->cb_size + len);
if (buf == NULL)
return got_error_from_errno("reallocarray");
b->cb_buf = buf;
b->cb_size += len;
return NULL;
}
