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/*
* Copyright (c) Christos Zoulas 2017.
* 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 immediately at the beginning of the file, without modification,
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 "file.h"
#ifndef lint
FILE_RCSID("@(#)$File: buffer.c,v 1.13 2023/07/02 12:48:39 christos Exp $")
#endif /* lint */
#include "magic.h"
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
void
buffer_init(struct buffer *b, int fd, const struct stat *st, const void *data,
size_t len)
{
b->fd = fd;
if (st)
memcpy(&b->st, st, sizeof(b->st));
else if (b->fd == -1 || fstat(b->fd, &b->st) == -1)
memset(&b->st, 0, sizeof(b->st));
b->fbuf = data;
b->flen = len;
b->eoff = 0;
b->ebuf = NULL;
b->elen = 0;
}
void
buffer_fini(struct buffer *b)
{
free(b->ebuf);
b->ebuf = NULL;
b->elen = 0;
}
int
buffer_fill(const struct buffer *bb)
{
struct buffer *b = CCAST(struct buffer *, bb);
if (b->elen != 0)
return b->elen == FILE_BADSIZE ? -1 : 0;
if (!S_ISREG(b->st.st_mode))
goto out;
b->elen = CAST(size_t, b->st.st_size) < b->flen ?
CAST(size_t, b->st.st_size) : b->flen;
if (b->elen == 0) {
free(b->ebuf);
b->ebuf = NULL;
return 0;
}
if ((b->ebuf = malloc(b->elen)) == NULL)
goto out;
b->eoff = b->st.st_size - b->elen;
if (pread(b->fd, b->ebuf, b->elen, b->eoff) == -1) {
free(b->ebuf);
b->ebuf = NULL;
goto out;
}
return 0;
out:
b->elen = FILE_BADSIZE;
return -1;
}
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