File: [local] / src / usr.bin / cvs / buf.c (download)
Revision 1.69, Wed Feb 27 22:34:04 2008 UTC (16 years, 3 months ago) by joris
Branch: MAIN
CVS Tags: OPENBSD_4_3_BASE, OPENBSD_4_3 Changes since 1.68: +7 -4 lines
prevent file races
ok tobias@
|
/* $OpenBSD: buf.c,v 1.69 2008/02/27 22:34:04 joris 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/stat.h>
#include <sys/time.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "atomicio.h"
#include "cvs.h"
#include "buf.h"
#define BUF_INCR 128
struct cvs_buf {
/* 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 cvs_buf_grow(BUF *, size_t);
/*
* cvs_buf_alloc()
*
* Create a new buffer structure and return a pointer to it. This structure
* uses dynamically-allocated memory and must be freed with cvs_buf_free(),
* once the buffer is no longer needed.
*/
BUF *
cvs_buf_alloc(size_t len)
{
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_size = len;
b->cb_len = 0;
return (b);
}
BUF *
cvs_buf_load(const char *path)
{
int fd;
BUF *bp;
if ((fd = open(path, O_RDONLY, 0600)) == -1)
fatal("cvs_buf_load: failed to load '%s' : %s", path,
strerror(errno));
bp = cvs_buf_load_fd(fd);
(void)close(fd);
return (bp);
}
BUF *
cvs_buf_load_fd(int fd)
{
struct stat st;
BUF *buf;
if (fstat(fd, &st) == -1)
fatal("cvs_buf_load_fd: fstat: %s", strerror(errno));
if (lseek(fd, 0, SEEK_SET) == -1)
fatal("cvs_buf_load_fd: lseek: %s", strerror(errno));
buf = cvs_buf_alloc(st.st_size);
if (atomicio(read, fd, buf->cb_buf, buf->cb_size) != buf->cb_size)
fatal("cvs_buf_load_fd: read: %s", strerror(errno));
buf->cb_len = buf->cb_size;
return (buf);
}
/*
* cvs_buf_free()
*
* Free the buffer <b> and all associated data.
*/
void
cvs_buf_free(BUF *b)
{
if (b->cb_buf != NULL)
xfree(b->cb_buf);
xfree(b);
}
/*
* cvs_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().
*/
u_char *
cvs_buf_release(BUF *b)
{
u_char *tmp;
tmp = b->cb_buf;
xfree(b);
return (tmp);
}
/*
* cvs_buf_empty()
*
* Empty the contents of the buffer <b> and reset pointers.
*/
void
cvs_buf_empty(BUF *b)
{
memset(b->cb_buf, 0, b->cb_size);
b->cb_len = 0;
}
/*
* cvs_buf_putc()
*
* Append a single character <c> to the end of the buffer <b>.
*/
void
cvs_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 */
cvs_buf_grow(b, (size_t)BUF_INCR);
/* the buffer might have been moved */
bp = b->cb_buf + b->cb_len;
}
*bp = (u_char)c;
b->cb_len++;
}
/*
* cvs_buf_getc()
*
* Return u_char at buffer position <pos>.
*
*/
u_char
cvs_buf_getc(BUF *b, size_t pos)
{
return (b->cb_buf[pos]);
}
/*
* cvs_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.
*/
void
cvs_buf_append(BUF *b, const void *data, size_t len)
{
size_t left;
u_char *bp, *bep;
bp = b->cb_buf + b->cb_len;
bep = b->cb_buf + b->cb_size;
left = bep - bp;
if (left < len) {
cvs_buf_grow(b, len - left);
bp = b->cb_buf + b->cb_len;
}
memcpy(bp, data, len);
b->cb_len += len;
}
/*
* cvs_buf_len()
*
* Returns the size of the buffer that is being used.
*/
size_t
cvs_buf_len(BUF *b)
{
return (b->cb_len);
}
/*
* cvs_buf_write_fd()
*
* Write the contents of the buffer <b> to the specified <fd>
*/
int
cvs_buf_write_fd(BUF *b, int fd)
{
if (atomicio(vwrite, fd, b->cb_buf, b->cb_len) != b->cb_len)
return (-1);
return (0);
}
/*
* cvs_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
cvs_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
fatal("open: `%s': %s", path, strerror(errno));
}
if (cvs_buf_write_fd(b, fd) == -1) {
(void)unlink(path);
fatal("cvs_buf_write: cvs_buf_write_fd: `%s'", path);
}
if (fchmod(fd, mode) < 0)
cvs_log(LP_ERR, "permissions not set on file %s", path);
(void)close(fd);
return (0);
}
/*
* cvs_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
*/
int
cvs_buf_write_stmp(BUF *b, char *template, struct timeval *tv)
{
int fd;
if ((fd = mkstemp(template)) == -1)
fatal("mkstemp: `%s': %s", template, strerror(errno));
if (cvs_buf_write_fd(b, fd) == -1) {
(void)unlink(template);
fatal("cvs_buf_write_stmp: cvs_buf_write_fd: `%s'", template);
}
if (tv != NULL) {
if (futimes(fd, tv) == -1)
fatal("cvs_buf_write_stmp: futimes failed");
}
cvs_worklist_add(template, &temp_files);
if (lseek(fd, SEEK_SET, 0) < 0)
fatal("cvs_buf_write_stmp: lseek: %s", strerror(errno));
return (fd);
}
/*
* cvs_buf_grow()
*
* Grow the buffer <b> by <len> bytes. The contents are unchanged by this
* operation regardless of the result.
*/
static void
cvs_buf_grow(BUF *b, size_t len)
{
b->cb_buf = xrealloc(b->cb_buf, 1, b->cb_size + len);
b->cb_size += len;
}
/*
* cvs_buf_copy()
*
* Copy the first <len> bytes of data in the buffer <b> starting at offset
* <off> in the destination buffer <dst>, which can accept up to <len> bytes.
* Returns the number of bytes successfully copied, or -1 on failure.
*/
ssize_t
cvs_buf_copy(BUF *b, size_t off, void *dst, size_t len)
{
size_t rc;
if (off > b->cb_len)
fatal("cvs_buf_copy failed");
rc = MIN(len, (b->cb_len - off));
memcpy(dst, b->cb_buf + off, rc);
return (ssize_t)rc;
}
/*
* cvs_buf_peek()
*
* Peek at the contents of the buffer <b> at offset <off>.
*/
const u_char *
cvs_buf_peek(BUF *b, size_t off)
{
if (off >= b->cb_len)
return (NULL);
return (b->cb_buf + off);
}
int
cvs_buf_differ(const BUF *b1, const BUF *b2)
{
if (b1->cb_len != b2->cb_len)
return (1);
return (memcmp(b1->cb_buf, b2->cb_buf, b1->cb_len));
}