OpenBSD-4.6/usr.bin/rcs/buf.c
/* $OpenBSD: buf.c,v 1.13 2007/05/29 00:19:10 ray 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 <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "buf.h"
#include "xmalloc.h"
#include "worklist.h"
#define BUF_INCR 128
struct rcs_buf {
u_int cb_flags;
/* buffer handle, buffer size, and data length */
u_char *cb_buf;
size_t cb_size;
size_t cb_len;
};
#define SIZE_LEFT(b) (b->cb_size - b->cb_len)
static void rcs_buf_grow(BUF *, size_t);
/*
* rcs_buf_alloc()
*
* Create a new buffer structure and return a pointer to it. This structure
* uses dynamically-allocated memory and must be freed with rcs_buf_free(),
* once the buffer is no longer needed.
*/
BUF *
rcs_buf_alloc(size_t len, u_int flags)
{
BUF *b;
b = xmalloc(sizeof(*b));
/* Postpone creation of zero-sized buffers */
if (len > 0)
b->cb_buf = xcalloc(1, len);
else
b->cb_buf = NULL;
b->cb_flags = flags;
b->cb_size = len;
b->cb_len = 0;
return (b);
}
/*
* rcs_buf_load()
*
* 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.
*/
BUF *
rcs_buf_load(const char *path, u_int flags)
{
int fd;
ssize_t ret;
size_t len;
u_char *bp;
struct stat st;
BUF *buf;
buf = NULL;
if ((fd = open(path, O_RDONLY, 0600)) == -1)
goto out;
if (fstat(fd, &st) == -1)
goto out;
if (st.st_size > SIZE_MAX) {
errno = EFBIG;
goto out;
}
buf = rcs_buf_alloc(st.st_size, flags);
for (bp = buf->cb_buf; ; bp += (size_t)ret) {
len = SIZE_LEFT(buf);
ret = read(fd, bp, len);
if (ret == -1) {
int saved_errno;
saved_errno = errno;
rcs_buf_free(buf);
buf = NULL;
errno = saved_errno;
goto out;
} else if (ret == 0)
break;
buf->cb_len += (size_t)ret;
}
out:
if (fd != -1) {
int saved_errno;
/* We may want to preserve errno here. */
saved_errno = errno;
(void)close(fd);
errno = saved_errno;
}
return (buf);
}
/*
* rcs_buf_free()
*
* Free the buffer <b> and all associated data.
*/
void
rcs_buf_free(BUF *b)
{
if (b->cb_buf != NULL)
xfree(b->cb_buf);
xfree(b);
}
/*
* rcs_buf_release()
*
* 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 *
rcs_buf_release(BUF *b)
{
void *tmp;
tmp = b->cb_buf;
xfree(b);
return (tmp);
}
/*
* rcs_buf_get()
*/
u_char *
rcs_buf_get(BUF *b)
{
return (b->cb_buf);
}
/*
* rcs_buf_empty()
*
* Empty the contents of the buffer <b> and reset pointers.
*/
void
rcs_buf_empty(BUF *b)
{
memset(b->cb_buf, 0, b->cb_size);
b->cb_len = 0;
}
/*
* rcs_buf_putc()
*
* Append a single character <c> to the end of the buffer <b>.
*/
void
rcs_buf_putc(BUF *b, int c)
{
u_char *bp;
bp = b->cb_buf + b->cb_len;
if (bp == (b->cb_buf + b->cb_size)) {
/* extend */
if (b->cb_flags & BUF_AUTOEXT)
rcs_buf_grow(b, (size_t)BUF_INCR);
else
errx(1, "rcs_buf_putc failed");
/* the buffer might have been moved */
bp = b->cb_buf + b->cb_len;
}
*bp = (u_char)c;
b->cb_len++;
}
/*
* rcs_buf_getc()
*
* Return u_char at buffer position <pos>.
*
*/
u_char
rcs_buf_getc(BUF *b, size_t pos)
{
return (b->cb_buf[pos]);
}
/*
* rcs_buf_append()
*
* 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 attempt to append as much
* data as possible, or if the BUF_AUTOEXT flag is set for the buffer, it
* will get resized to an appropriate size to accept all data.
* Returns the number of bytes successfully appended to the buffer.
*/
size_t
rcs_buf_append(BUF *b, const void *data, size_t len)
{
size_t left, rlen;
u_char *bp, *bep;
bp = b->cb_buf + b->cb_len;
bep = b->cb_buf + b->cb_size;
left = bep - bp;
rlen = len;
if (left < len) {
if (b->cb_flags & BUF_AUTOEXT) {
rcs_buf_grow(b, len - left);
bp = b->cb_buf + b->cb_len;
} else
rlen = bep - bp;
}
memcpy(bp, data, rlen);
b->cb_len += rlen;
return (rlen);
}
/*
* rcs_buf_fappend()
*
*/
size_t
rcs_buf_fappend(BUF *b, const char *fmt, ...)
{
size_t ret;
int n;
char *str;
va_list vap;
va_start(vap, fmt);
n = vasprintf(&str, fmt, vap);
va_end(vap);
if (n == -1)
errx(1, "rcs_buf_fappend: failed to format data");
ret = rcs_buf_append(b, str, n);
xfree(str);
return (ret);
}
/*
* rcs_buf_len()
*
* Returns the size of the buffer that is being used.
*/
size_t
rcs_buf_len(BUF *b)
{
return (b->cb_len);
}
/*
* rcs_buf_write_fd()
*
* Write the contents of the buffer <b> to the specified <fd>
*/
int
rcs_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);
}
/*
* rcs_buf_write()
*
* 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>.
*/
int
rcs_buf_write(BUF *b, const char *path, mode_t mode)
{
int fd;
open:
if ((fd = open(path, O_WRONLY|O_CREAT|O_TRUNC, mode)) == -1) {
if (errno == EACCES && unlink(path) != -1)
goto open;
else
err(1, "%s", path);
}
if (rcs_buf_write_fd(b, fd) == -1) {
(void)unlink(path);
errx(1, "rcs_buf_write: rcs_buf_write_fd: `%s'", path);
}
if (fchmod(fd, mode) < 0)
warn("permissions not set on file %s", path);
(void)close(fd);
return (0);
}
/*
* rcs_buf_write_stmp()
*
* 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
*/
void
rcs_buf_write_stmp(BUF *b, char *template)
{
int fd;
if ((fd = mkstemp(template)) == -1)
err(1, "%s", template);
rcs_worklist_add(template, &rcs_temp_files);
if (rcs_buf_write_fd(b, fd) == -1) {
(void)unlink(template);
errx(1, "rcs_buf_write_stmp: rcs_buf_write_fd: `%s'", template);
}
(void)close(fd);
}
/*
* rcs_buf_grow()
*
* Grow the buffer <b> by <len> bytes. The contents are unchanged by this
* operation regardless of the result.
*/
static void
rcs_buf_grow(BUF *b, size_t len)
{
b->cb_buf = xrealloc(b->cb_buf, 1, b->cb_size + len);
b->cb_size += len;
}