diff options
author | Peter Jones <pjones@redhat.com> | 2007-01-29 21:49:45 +0000 |
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committer | Peter Jones <pjones@redhat.com> | 2007-01-29 21:49:45 +0000 |
commit | 410a8b3c63b178560b8b007e66f6618754039cc0 (patch) | |
tree | 4866d67a80ce4d05ce8cc8af364c2e25c8b0a3a6 /src/pm-reset-swap.c | |
parent | 3c086a1670d928452b009a9e1269af0ab1b956b7 (diff) |
- Add a utility to remove the S1SUSPEND stamp from a swap device.
Diffstat (limited to 'src/pm-reset-swap.c')
-rw-r--r-- | src/pm-reset-swap.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/src/pm-reset-swap.c b/src/pm-reset-swap.c new file mode 100644 index 0000000..2f372ea --- /dev/null +++ b/src/pm-reset-swap.c @@ -0,0 +1,167 @@ +/* + * 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)) + 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; + } + rc = 1; + 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 + */ |