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/fiemap.c

Created Aug 7, 2013
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/*
* Copyright (C) 2010 Canonical
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
/*
* Author Colin Ian King, colin.king@canonical.com
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <linux/fs.h>
#include <linux/fiemap.h>
void syntax(char **argv)
{
fprintf(stderr, "%s [filename] [start] [length]...\n",argv[0]);
}
struct fiemap *read_fiemap(int fd, __u64 start, __u64 length)
{
struct fiemap *fiemap;
int extents_size;
if ((fiemap = (struct fiemap*)malloc(sizeof(struct fiemap))) == NULL) {
fprintf(stderr, "Out of memory allocating fiemap\n");
return NULL;
}
memset(fiemap, 0, sizeof(struct fiemap));
fiemap->fm_start = start;
fiemap->fm_length = length; /* Lazy */
fiemap->fm_flags = 0;
fiemap->fm_extent_count = 0;
fiemap->fm_mapped_extents = 0;
printf("start: %x, length: %x\n", start, length);
/* Find out how many extents there are */
if (ioctl(fd, FS_IOC_FIEMAP, fiemap) < 0) {
fprintf(stderr, "fiemap ioctl() failed\n");
return NULL;
}
/* Read in the extents */
extents_size = sizeof(struct fiemap_extent) *
(fiemap->fm_mapped_extents);
/* Resize fiemap to allow us to read in the extents */
if ((fiemap = (struct fiemap*)realloc(fiemap,sizeof(struct fiemap) +
extents_size)) == NULL) {
fprintf(stderr, "Out of memory allocating fiemap\n");
return NULL;
}
memset(fiemap->fm_extents, 0, extents_size);
fiemap->fm_extent_count = fiemap->fm_mapped_extents;
fiemap->fm_mapped_extents = 0;
if (ioctl(fd, FS_IOC_FIEMAP, fiemap) < 0) {
fprintf(stderr, "fiemap ioctl() failed\n");
return NULL;
}
return fiemap;
}
void dump_fiemap(struct fiemap *fiemap, char *filename)
{
int i;
printf("File %s has %d extents:\n",filename, fiemap->fm_mapped_extents);
printf("#\tLogical Physical Length Flags\n");
for (i=0;i<fiemap->fm_mapped_extents;i++) {
printf("%d:\t%-16.16llx %-16.16llx %-16.16llx %-4.4x\n",
i,
fiemap->fm_extents[i].fe_logical,
fiemap->fm_extents[i].fe_physical,
fiemap->fm_extents[i].fe_length,
fiemap->fm_extents[i].fe_flags);
}
printf("\n");
}
int main(int argc, char **argv)
{
int i;
if (argc < 4) {
syntax(argv);
exit(EXIT_FAILURE);
}
int fd;
if ((fd = open(argv[1], O_RDONLY)) < 0) {
fprintf(stderr, "Cannot open file %s\n", argv[i]);
}
else {
struct fiemap *fiemap;
if ((fiemap = read_fiemap(fd, (__u64)atoi(argv[2]), (__u64)atoi(argv[3]))) != NULL)
dump_fiemap(fiemap, argv[1]);
close(fd);
}
exit(EXIT_SUCCESS);
}
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