Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 | /* 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(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;
/* fsetfilecon_raw is hidden */
if (strcmp(oldcon, newcon) != 0 && fsetfilecon(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
/* from Linux 2.6.23 */
/*
* Magic header for a swap area. ... Note that the first
* kilobyte is reserved for boot loader or disk label stuff.
*/
struct swap_header_v1 {
/* char bootbits[1024]; Space for disklabel etc. */
uint32_t version; /* second kbyte, word 0 */
uint32_t last_page; /* 1 */
uint32_t nr_badpages; /* 2 */
char sws_uuid[16]; /* 3,4,5,6 */
char sws_volume[16]; /* 7,8,9,10 */
uint32_t padding[117]; /* 11..127 */
uint32_t badpages[1]; /* 128 */
/* total 129 32-bit words in 2nd kilobyte */
} FIX_ALIASING;
#define NWORDS 129
#define hdr ((struct swap_header_v1*)bb_common_bufsiz1)
struct BUG_sizes {
char swap_header_v1_wrong[sizeof(*hdr) != (NWORDS * 4) ? -1 : 1];
char 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 UNUSED_PARAM, char **argv)
{
int fd;
unsigned pagesize;
off_t len;
const char *label = "";
opt_complementary = "-1"; /* at least one param */
/* TODO: -p PAGESZ, -U UUID */
getopt32(argv, "L:", &label);
argv += optind;
fd = xopen(argv[0], O_WRONLY);
/* Figure out how big the device is */
len = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ 1);
pagesize = getpagesize();
len -= pagesize;
/* Announce our intentions */
printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len);
mkswap_selinux_setcontext(fd, argv[0]);
/* Make a header. hdr is zero-filled so far... */
hdr->version = 1;
hdr->last_page = (uoff_t)len / pagesize;
if (ENABLE_FEATURE_MKSWAP_UUID) {
char uuid_string[32];
generate_uuid((void*)hdr->sws_uuid);
bin2hex(uuid_string, hdr->sws_uuid, 16);
/* f.e. UUID=dfd9c173-be52-4d27-99a5-c34c6c2ff55f */
printf("UUID=%.8s" "-%.4s-%.4s-%.4s-%.12s\n",
uuid_string,
uuid_string+8,
uuid_string+8+4,
uuid_string+8+4+4,
uuid_string+8+4+4+4
);
}
safe_strncpy(hdr->sws_volume, label, 16);
/* 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;
}
|