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/* 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
int mkswap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int mkswap_main(int argc, char **argv)
{
int fd, pagesize;
off_t len;
unsigned int hdr[129];
// 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.
memset(hdr, 0, sizeof(hdr));
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, sizeof(hdr));
xlseek(fd, pagesize - 10, SEEK_SET);
xwrite(fd, "SWAPSPACE2", 10);
fsync(fd);
if (ENABLE_FEATURE_CLEAN_UP) close(fd);
return 0;
}
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