diff options
Diffstat (limited to 'util-linux/mkswap.c')
| -rw-r--r-- | util-linux/mkswap.c | 45 |
1 files changed, 39 insertions, 6 deletions
diff --git a/util-linux/mkswap.c b/util-linux/mkswap.c index 31d5773..bf0d7b0 100644 --- a/util-linux/mkswap.c +++ b/util-linux/mkswap.c @@ -50,12 +50,47 @@ static void mkswap_selinux_setcontext(int fd, const char *path) #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; - unsigned int hdr[129]; // No options supported. @@ -74,9 +109,7 @@ int mkswap_main(int argc, char **argv) len - pagesize); mkswap_selinux_setcontext(fd, argv[1]); - // Make a header. - - memset(hdr, 0, sizeof(hdr)); + // Make a header. hdr is zero-filled so far... hdr[0] = 1; hdr[1] = (len / pagesize) - 1; @@ -84,9 +117,9 @@ int mkswap_main(int argc, char **argv) // signature on disk (not in cache) during swapon. xlseek(fd, 1024, SEEK_SET); - xwrite(fd, hdr, sizeof(hdr)); + xwrite(fd, hdr, NWORDS * 4); xlseek(fd, pagesize - 10, SEEK_SET); - xwrite(fd, "SWAPSPACE2", 10); + xwrite(fd, SWAPSPACE2, 10); fsync(fd); if (ENABLE_FEATURE_CLEAN_UP) close(fd); |