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mkswap: add -L LABEL option. closes bug 689.

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-11-03 05:51:20 +01:00
parent c6fb2a6b5f
commit 68c67469aa
2 changed files with 51 additions and 57 deletions
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14
include/usage.h
View File

@ -2815,17 +2815,11 @@
"$ mknod -m 644 /tmp/pipe p\n" "$ mknod -m 644 /tmp/pipe p\n"
#define mkswap_trivial_usage \ #define mkswap_trivial_usage \
"DEVICE" "[OPTIONS] BLOCKDEV" /* [SIZE_IN_KB] */
#define mkswap_full_usage "\n\n" \ #define mkswap_full_usage "\n\n" \
"Prepare block device to be used as swap partition" "Prepare BLOCKDEV to be used as swap partition\n" \
#if 0 "\nOptions:" \
"[-c] [-v0|-v1] DEVICE [BLOCKS]" "\n -L LBL Label" \
"\nOptions:"
"\n -c Check for readability"
"\n -v0 Make swap version 0 (max 128M)"
"\n -v1 Make swap version 1 (default for kernels > 2.1.117)"
"\n BLOCKS Number of blocks to use (default is entire partition)"
#endif
#define mktemp_trivial_usage \ #define mktemp_trivial_usage \
"[-dt] [-p DIR] [TEMPLATE]" "[-dt] [-p DIR] [TEMPLATE]"

94
util-linux/mkswap.c
View File

@ -50,72 +50,70 @@ static void mkswap_selinux_setcontext(int fd, const char *path)
# define mkswap_selinux_setcontext(fd, path) ((void)0) # define mkswap_selinux_setcontext(fd, path) ((void)0)
#endif #endif
#if 0 /* from Linux 2.6.23 */ /* from Linux 2.6.23 */
/* /*
* Magic header for a swap area. The first part of the union is * Magic header for a swap area. ... Note that the first
* what the swap magic looks like for the old (limited to 128MB) * kilobyte is reserved for boot loader or disk label stuff.
* 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 swap_header_v1 {
struct { /* char bootbits[1024]; Space for disklabel etc. */
char reserved[PAGE_SIZE - 10]; uint32_t version; /* second kbyte, word 0 */
char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ uint32_t last_page; /* 1 */
} magic; uint32_t nr_badpages; /* 2 */
struct { char sws_uuid[16]; /* 3,4,5,6 */
char bootbits[1024]; /* Space for disklabel etc. */ char sws_volume[16]; /* 7,8,9,10 */
__u32 version; /* second kbyte, word 0 */ uint32_t padding[117]; /* 11..127 */
__u32 last_page; /* 1 */ uint32_t badpages[1]; /* 128 */
__u32 nr_badpages; /* 2 */ /* total 129 32-bit words in 2nd kilobyte */
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 NWORDS 129
#define hdr ((uint32_t*)(&bb_common_bufsiz1)) #define hdr ((struct swap_header_v1*)bb_common_bufsiz1)
struct BUG_bufsiz1_is_too_small { struct BUG_sizes {
char BUG_bufsiz1_is_too_small[COMMON_BUFSIZE < (NWORDS * 4) ? -1 : 1]; 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 */ /* Stored without terminating NUL */
static const char SWAPSPACE2[sizeof("SWAPSPACE2")-1] ALIGN1 = "SWAPSPACE2"; 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) MAIN_EXTERNALLY_VISIBLE;
int mkswap_main(int argc, char **argv) int mkswap_main(int argc UNUSED_PARAM, char **argv)
{ {
int fd, pagesize; int fd;
unsigned pagesize;
off_t len; off_t len;
const char *label = "";
// No options supported. opt_complementary = "=1";
/* TODO: -p PAGESZ, -U UUID,
* optional SIZE_IN_KB 2nd param
*/
getopt32(argv, "L:", &label);
argv += optind;
if (argc != 2) bb_show_usage(); fd = xopen(argv[0], O_WRONLY);
// Figure out how big the device is and announce our intentions. /* 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 */ /* fdlength was reported to be unreliable - use seek */
len = xlseek(fd, 0, SEEK_END); len = xlseek(fd, 0, SEEK_END);
#if ENABLE_SELINUX if (ENABLE_SELINUX)
xlseek(fd, 0, SEEK_SET); xlseek(fd, 0, SEEK_SET);
#endif
pagesize = getpagesize(); pagesize = getpagesize();
printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len -= pagesize;
len - pagesize); printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len);
mkswap_selinux_setcontext(fd, argv[1]); 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;
// Make a header. hdr is zero-filled so far...
hdr[0] = 1;
hdr[1] = (len / pagesize) - 1;
if (ENABLE_FEATURE_MKSWAP_UUID) { if (ENABLE_FEATURE_MKSWAP_UUID) {
char uuid_string[32]; char uuid_string[32];
generate_uuid((void*) &hdr[3]); generate_uuid((void*)hdr->sws_uuid);
bin2hex(uuid_string, (void*) &hdr[3], 16); bin2hex(uuid_string, hdr->sws_uuid, 16);
/* f.e. UUID=dfd9c173-be52-4d27-99a5-c34c6c2ff55f */ /* f.e. UUID=dfd9c173-be52-4d27-99a5-c34c6c2ff55f */
printf("UUID=%.8s" "-%.4s-%.4s-%.4s-%.12s\n", printf("UUID=%.8s" "-%.4s-%.4s-%.4s-%.12s\n",
uuid_string, uuid_string,
@ -125,16 +123,18 @@ int mkswap_main(int argc, char **argv)
uuid_string+8+4+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 /* Write the header. Sync to disk because some kernel versions check
// signature on disk (not in cache) during swapon. * signature on disk (not in cache) during swapon. */
xlseek(fd, 1024, SEEK_SET); xlseek(fd, 1024, SEEK_SET);
xwrite(fd, hdr, NWORDS * 4); xwrite(fd, hdr, NWORDS * 4);
xlseek(fd, pagesize - 10, SEEK_SET); xlseek(fd, pagesize - 10, SEEK_SET);
xwrite(fd, SWAPSPACE2, 10); xwrite(fd, SWAPSPACE2, 10);
fsync(fd); fsync(fd);
if (ENABLE_FEATURE_CLEAN_UP) close(fd); if (ENABLE_FEATURE_CLEAN_UP)
close(fd);
return 0; return 0;
} }