Hi Jason,
good idea, but I have a few notes:
On Thu, Mar 04, 2010 at 12:29:51PM -0700, Jason Borden wrote:
>
> This patch adds a new program to the project which is analogous to e2label
> but for swap partitions. The reason behind having this program is to allow
it would be nice to use the same tool for UUID changes.
> +#include <stdio.h>
> +#include <string.h>
> +#include <fcntl.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <unistd.h>
> +#include <stdlib.h>
> +#include <stdarg.h>
> +#include <errno.h>
> +#include "nls.h"
> +
> +#define SWAP_MAGIC_OFFSET 0xFF6
The position of the magic string depends on the page size, there is
five offsets where you can found the magic (0xff6, 0x1ff6, 0x3ff6,
0x7ff6 and 0xfff6).
The ideal solution is use libblkid to check that the device really
contains a swap. See shlibs/blkid/samples/superblocks.c.
The libblkid also returns LABEL and UUID from the device.
> +#define SWAP_MAGIC_VALUE "SWAPSPACE2"
> +#define SWAP_MAGIC_LENGTH 10
> +
> +#define SWAP_LABEL_OFFSET 0x41C
> +#define SWAP_LABEL_LENGTH 16
> +
> +/* A function to print errors and exit */
> +static void perror_exit(const char *perrorstr, int exitcode, const char
> *stder
> rstr, ...)
> +{
> + va_list ap;
> +
> + if (perrorstr)
> + perror(perrorstr);
> + va_start(ap, stderrstr);
> + vfprintf(stderr, stderrstr, ap);
> + va_end(ap);
> + exit(exitcode);
> +}
#include <err.h> and use errx() and err().
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
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