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/*
* mark a swap device as not usable for thaw
*
* Copyright 2006 Red Hat, Inc.
*
* Authors:
* Peter Jones <pjones@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#define _GNU_SOURCE 1
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
/* XXX this is a total hack for bad system headers. */
typedef u_int32_t __u32;
#include <linux/pmu.h>
typedef u_int64_t sector_t;
/*
* Here's what the disk looks like after a successful hibernate:
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000400 01 00 00 00 ff df 03 00 00 00 00 00 00 00 00 00 |................|
00000410 00 00 00 00 00 00 00 00 00 00 00 00 73 77 61 70 |............swap|
00000420 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000fe0 00 00 00 00 01 00 00 00 00 00 00 00 53 57 41 50 |............SWAP|
00000ff0 53 50 41 43 45 32 53 31 53 55 53 50 45 4e 44 00 |SPACE2S1SUSPEND.|
* And here's what it looks like if you haven't hibernated to it:
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000400 01 00 00 00 ff df 03 00 00 00 00 00 00 00 00 00 |................|
00000410 00 00 00 00 00 00 00 00 00 00 00 00 73 77 61 70 |............swap|
00000420 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
00000ff0 00 00 00 00 00 00 53 57 41 50 53 50 41 43 45 32 |......SWAPSPACE2|
*
*/
/* The signature offset is annoying. The struct is:
* struct swsusp_header {
* char reserved[PAGE_SIZE - 20 - sizeof(sector_t)];
* sector_t image;
* char orig_sig[10];
* char sig[10];
* }
*/
off_t get_sig_offset(int orig)
{
int pagesize = sysconf(_SC_PAGESIZE);
return (off_t)((sizeof (char) * pagesize) - (orig ? 20 : 10));
}
static inline int
print_usage(FILE *output, int retval)
{
fprintf(output, "usage: pm-reset-swap <device node>\n");
return retval;
}
int check_resume_block(FILE *dev, off_t offset)
{
char buf[11] = {0,};
off_t location = offset + get_sig_offset(0);
if (fseek(dev, location, SEEK_SET) < 0)
return -1;
if (fread(buf, sizeof (char), 10, dev) != 10)
return -1;
if (!strncmp(buf, "S1SUSPEND", 9) ||
!strncmp(buf, "ULSUSPEND", 9))
return 1;
return 0;
}
int clear_resume_block(FILE *dev, off_t offset)
{
char buf[21] = {0,};
off_t location = offset + get_sig_offset(1);
if (fseek(dev, location, SEEK_SET) < 0)
return -1;
if (fread(buf, sizeof (char), 20, dev) != 20)
return -1;
if (fseek(dev, location, SEEK_SET) < 0)
return -1;
memmove(buf+10, buf, 10);
memset(buf, '\0', 10);
if (fwrite(buf, sizeof (char), 20, dev) != 20)
return -1;
return 0;
}
int main(int argc, char *argv[])
{
FILE *dev = NULL;
int rc;
if (argc != 2)
return print_usage(stderr, 1);
if (!strcmp(argv[1], "--help")) {
return print_usage(stdout, 0);
}
if (!(dev = fopen(argv[1], "r+b"))) {
fprintf(stderr, "Could not open \"%s\": %m\n", argv[1]);
return 1;
}
rc = check_resume_block(dev, 0);
if (rc < 0) {
fprintf(stderr, "Could not check \"%s\" for swap signature: %m\n",
argv[1]);
fclose(dev);
return 2;
}
if (rc == 1) {
if (clear_resume_block(dev, 0)) {
fprintf(stderr, "Could not clear swap signature on \"%s\": %m\n",
argv[1]);
fclose(dev);
return 1;
}
}
fclose(dev);
return 0;
}
/*
* vim:ts=8:sw=4:sts=4:et
*/
|
