freebsd-dev/lib/libarchive/archive_read_open_file.c
Tim Kientzle 3f6c3bcd84 Fix 'bsdtar -t' on tape drives. Libarchive uses the
skip() callback to skip over data when reading uncompressed
archives.  This gets invoked, for example, during tar -t
or tar -x with a filename argument.  The revised code
only calls [lf]seek() on regular files, instead of depending
on the kernel to return an error.

Thanks to: bde for explaining the implementation of lseek()
Thanks to: Daniel O'Connor for testing
Approved by: re (Ken Smith)
MFC after: 5 days
2007-06-26 03:06:48 +00:00

168 lines
4.4 KiB
C

/*-
* Copyright (c) 2003-2007 Tim Kientzle
* 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. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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(S) 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 "archive_platform.h"
__FBSDID("$FreeBSD$");
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "archive.h"
struct read_FILE_data {
FILE *f;
size_t block_size;
void *buffer;
char can_skip;
};
static int file_close(struct archive *, void *);
static int file_open(struct archive *, void *);
static ssize_t file_read(struct archive *, void *, const void **buff);
#if ARCHIVE_API_VERSION < 2
static ssize_t file_skip(struct archive *, void *, size_t request);
#else
static off_t file_skip(struct archive *, void *, off_t request);
#endif
int
archive_read_open_FILE(struct archive *a, FILE *f)
{
struct read_FILE_data *mine;
mine = (struct read_FILE_data *)malloc(sizeof(*mine));
if (mine == NULL) {
archive_set_error(a, ENOMEM, "No memory");
return (ARCHIVE_FATAL);
}
mine->block_size = 128 * 1024;
mine->buffer = malloc(mine->block_size);
if (mine->buffer == NULL) {
archive_set_error(a, ENOMEM, "No memory");
free(mine);
return (ARCHIVE_FATAL);
}
mine->f = f;
/* Suppress skip by default. See below. */
mine->can_skip = 0;
return (archive_read_open2(a, mine, file_open, file_read,
file_skip, file_close));
}
static int
file_open(struct archive *a, void *client_data)
{
struct read_FILE_data *mine = (struct read_FILE_data *)client_data;
struct stat st;
/*
* If we can't fstat() the file, it may just be that
* it's not a file. (FILE * objects can wrap many kinds
* of I/O streams.)
*/
if (fstat(fileno(mine->f), &st) == 0 && S_ISREG(st.st_mode)) {
archive_read_extract_set_skip_file(a, st.st_dev, st.st_ino);
/* Enable the seek optimization for regular files. */
mine->can_skip = 1;
}
return (ARCHIVE_OK);
}
static ssize_t
file_read(struct archive *a, void *client_data, const void **buff)
{
struct read_FILE_data *mine = (struct read_FILE_data *)client_data;
ssize_t bytes_read;
*buff = mine->buffer;
bytes_read = fread(mine->buffer, 1, mine->block_size, mine->f);
if (bytes_read < 0) {
archive_set_error(a, errno, "Error reading file");
}
return (bytes_read);
}
#if ARCHIVE_API_VERSION < 2
static ssize_t
file_skip(struct archive *a, void *client_data, size_t request)
#else
static off_t
file_skip(struct archive *a, void *client_data, off_t request)
#endif
{
struct read_FILE_data *mine = (struct read_FILE_data *)client_data;
(void)a; /* UNUSED */
/*
* If we can't skip, return 0 as the amount we did step and
* the caller will work around by reading and discarding.
*/
if (!mine->can_skip)
return (0);
if (request == 0)
return (0);
#if HAVE_FSEEKO
if (fseeko(mine->f, request, SEEK_CUR) != 0)
#else
if (fseek(mine->f, request, SEEK_CUR) != 0)
#endif
{
mine->can_skip = 0;
return (0);
}
return (request);
}
static int
file_close(struct archive *a, void *client_data)
{
struct read_FILE_data *mine = (struct read_FILE_data *)client_data;
(void)a; /* UNUSED */
if (mine->buffer != NULL)
free(mine->buffer);
free(mine);
return (ARCHIVE_OK);
}