9d96af2e83
mkswap: use uint32, not int, to match kernel. mkswap: optimization: use pre-zeroed buffer
129 lines
3.4 KiB
C
129 lines
3.4 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/* mkswap.c - format swap device (Linux v1 only)
|
|
*
|
|
* Copyright 2006 Rob Landley <rob@landley.net>
|
|
*
|
|
* Licensed under GPL version 2, see file LICENSE in this tarball for details.
|
|
*/
|
|
|
|
#include "libbb.h"
|
|
|
|
#if ENABLE_SELINUX
|
|
static void mkswap_selinux_setcontext(int fd, const char *path)
|
|
{
|
|
struct stat stbuf;
|
|
|
|
if (!is_selinux_enabled())
|
|
return;
|
|
|
|
if (fstat(fd, &stbuf) < 0)
|
|
bb_perror_msg_and_die("fstat failed");
|
|
if (S_ISREG(stbuf.st_mode)) {
|
|
security_context_t newcon;
|
|
security_context_t oldcon = NULL;
|
|
context_t context;
|
|
|
|
if (fgetfilecon_raw(fd, &oldcon) < 0) {
|
|
if (errno != ENODATA)
|
|
goto error;
|
|
if (matchpathcon(path, stbuf.st_mode, &oldcon) < 0)
|
|
goto error;
|
|
}
|
|
context = context_new(oldcon);
|
|
if (!context || context_type_set(context, "swapfile_t"))
|
|
goto error;
|
|
newcon = context_str(context);
|
|
if (!newcon)
|
|
goto error;
|
|
if (strcmp(oldcon, newcon) != 0 && fsetfilecon_raw(fd, newcon) < 0)
|
|
goto error;
|
|
if (ENABLE_FEATURE_CLEAN_UP) {
|
|
context_free(context);
|
|
freecon(oldcon);
|
|
}
|
|
}
|
|
return;
|
|
error:
|
|
bb_perror_msg_and_die("SELinux relabeling failed");
|
|
}
|
|
#else
|
|
#define mkswap_selinux_setcontext(fd, path) ((void)0)
|
|
#endif
|
|
|
|
#if 0 /* from Linux 2.6.23 */
|
|
/*
|
|
* Magic header for a swap area. The first part of the union is
|
|
* what the swap magic looks like for the old (limited to 128MB)
|
|
* swap area format, the second part of the union adds - in the
|
|
* old reserved area - some extra information. Note that the first
|
|
* kilobyte is reserved for boot loader or disk label stuff...
|
|
*/
|
|
union swap_header {
|
|
struct {
|
|
char reserved[PAGE_SIZE - 10];
|
|
char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
|
|
} magic;
|
|
struct {
|
|
char bootbits[1024]; /* Space for disklabel etc. */
|
|
__u32 version; /* second kbyte, word 0 */
|
|
__u32 last_page; /* 1 */
|
|
__u32 nr_badpages; /* 2 */
|
|
unsigned char sws_uuid[16]; /* 3,4,5,6 */
|
|
unsigned char sws_volume[16]; /* 7,8,9,10 */
|
|
__u32 padding[117]; /* 11..127 */
|
|
__u32 badpages[1]; /* 128, total 129 32-bit words */
|
|
} info;
|
|
};
|
|
#endif
|
|
|
|
#define NWORDS 129
|
|
#define hdr ((uint32_t*)(&bb_common_bufsiz1))
|
|
|
|
struct BUG_bufsiz1_is_too_small {
|
|
char BUG_bufsiz1_is_too_small[COMMON_BUFSIZE < (NWORDS * 4) ? -1 : 1];
|
|
};
|
|
|
|
/* Stored without terminating NUL */
|
|
static const char SWAPSPACE2[sizeof("SWAPSPACE2")-1] ALIGN1 = "SWAPSPACE2";
|
|
|
|
int mkswap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
|
int mkswap_main(int argc, char **argv)
|
|
{
|
|
int fd, pagesize;
|
|
off_t len;
|
|
|
|
// No options supported.
|
|
|
|
if (argc != 2) bb_show_usage();
|
|
|
|
// Figure out how big the device is and announce our intentions.
|
|
|
|
fd = xopen(argv[1], O_RDWR);
|
|
/* fdlength was reported to be unreliable - use seek */
|
|
len = xlseek(fd, 0, SEEK_END);
|
|
#if ENABLE_SELINUX
|
|
xlseek(fd, 0, SEEK_SET);
|
|
#endif
|
|
pagesize = getpagesize();
|
|
printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n",
|
|
len - pagesize);
|
|
mkswap_selinux_setcontext(fd, argv[1]);
|
|
|
|
// Make a header. hdr is zero-filled so far...
|
|
hdr[0] = 1;
|
|
hdr[1] = (len / pagesize) - 1;
|
|
|
|
// Write the header. Sync to disk because some kernel versions check
|
|
// signature on disk (not in cache) during swapon.
|
|
|
|
xlseek(fd, 1024, SEEK_SET);
|
|
xwrite(fd, hdr, NWORDS * 4);
|
|
xlseek(fd, pagesize - 10, SEEK_SET);
|
|
xwrite(fd, SWAPSPACE2, 10);
|
|
fsync(fd);
|
|
|
|
if (ENABLE_FEATURE_CLEAN_UP) close(fd);
|
|
|
|
return 0;
|
|
}
|