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    Contents of /trunk/mkinitrd-magellan/busybox/util-linux/mkswap.c

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    Revision 984 - (show annotations) (download)
    Sun May 30 11:32:42 2010 UTC (13 years, 11 months ago) by niro
    File MIME type: text/plain
    File size: 3701 byte(s) 
    -updated to busybox-1.16.1 and enabled blkid/uuid support in default config
    1 /* vi: set sw=4 ts=4: */
    2 /* mkswap.c - format swap device (Linux v1 only)
    3 *
    4 * Copyright 2006 Rob Landley <rob@landley.net>
    5 *
    6 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
    7 */
    8 #include "libbb.h"
    9
    10 #if ENABLE_SELINUX
    11 static void mkswap_selinux_setcontext(int fd, const char *path)
    12 {
    13 struct stat stbuf;
    14
    15 if (!is_selinux_enabled())
    16 return;
    17
    18 if (fstat(fd, &stbuf) < 0)
    19 bb_perror_msg_and_die("fstat failed");
    20 if (S_ISREG(stbuf.st_mode)) {
    21 security_context_t newcon;
    22 security_context_t oldcon = NULL;
    23 context_t context;
    24
    25 if (fgetfilecon(fd, &oldcon) < 0) {
    26 if (errno != ENODATA)
    27 goto error;
    28 if (matchpathcon(path, stbuf.st_mode, &oldcon) < 0)
    29 goto error;
    30 }
    31 context = context_new(oldcon);
    32 if (!context || context_type_set(context, "swapfile_t"))
    33 goto error;
    34 newcon = context_str(context);
    35 if (!newcon)
    36 goto error;
    37 /* fsetfilecon_raw is hidden */
    38 if (strcmp(oldcon, newcon) != 0 && fsetfilecon(fd, newcon) < 0)
    39 goto error;
    40 if (ENABLE_FEATURE_CLEAN_UP) {
    41 context_free(context);
    42 freecon(oldcon);
    43 }
    44 }
    45 return;
    46 error:
    47 bb_perror_msg_and_die("SELinux relabeling failed");
    48 }
    49 #else
    50 # define mkswap_selinux_setcontext(fd, path) ((void)0)
    51 #endif
    52
    53 /* from Linux 2.6.23 */
    54 /*
    55 * Magic header for a swap area. ... Note that the first
    56 * kilobyte is reserved for boot loader or disk label stuff.
    57 */
    58 struct swap_header_v1 {
    59 /* char bootbits[1024]; Space for disklabel etc. */
    60 uint32_t version; /* second kbyte, word 0 */
    61 uint32_t last_page; /* 1 */
    62 uint32_t nr_badpages; /* 2 */
    63 char sws_uuid[16]; /* 3,4,5,6 */
    64 char sws_volume[16]; /* 7,8,9,10 */
    65 uint32_t padding[117]; /* 11..127 */
    66 uint32_t badpages[1]; /* 128 */
    67 /* total 129 32-bit words in 2nd kilobyte */
    68 };
    69
    70 #define NWORDS 129
    71 #define hdr ((struct swap_header_v1*)bb_common_bufsiz1)
    72
    73 struct BUG_sizes {
    74 char swap_header_v1_wrong[sizeof(*hdr) != (NWORDS * 4) ? -1 : 1];
    75 char bufsiz1_is_too_small[COMMON_BUFSIZE < (NWORDS * 4) ? -1 : 1];
    76 };
    77
    78 /* Stored without terminating NUL */
    79 static const char SWAPSPACE2[sizeof("SWAPSPACE2")-1] ALIGN1 = "SWAPSPACE2";
    80
    81 int mkswap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
    82 int mkswap_main(int argc UNUSED_PARAM, char **argv)
    83 {
    84 int fd;
    85 unsigned pagesize;
    86 off_t len;
    87 const char *label = "";
    88
    89 opt_complementary = "=1";
    90 /* TODO: -p PAGESZ, -U UUID,
    91 * optional SIZE_IN_KB 2nd param
    92 */
    93 getopt32(argv, "L:", &label);
    94 argv += optind;
    95
    96 fd = xopen(argv[0], O_WRONLY);
    97
    98 /* Figure out how big the device is and announce our intentions */
    99 /* fdlength was reported to be unreliable - use seek */
    100 len = xlseek(fd, 0, SEEK_END);
    101 if (ENABLE_SELINUX)
    102 xlseek(fd, 0, SEEK_SET);
    103
    104 pagesize = getpagesize();
    105 len -= pagesize;
    106 printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len);
    107 mkswap_selinux_setcontext(fd, argv[0]);
    108
    109 /* Make a header. hdr is zero-filled so far... */
    110 hdr->version = 1;
    111 hdr->last_page = (uoff_t)len / pagesize;
    112
    113 if (ENABLE_FEATURE_MKSWAP_UUID) {
    114 char uuid_string[32];
    115 generate_uuid((void*)hdr->sws_uuid);
    116 bin2hex(uuid_string, hdr->sws_uuid, 16);
    117 /* f.e. UUID=dfd9c173-be52-4d27-99a5-c34c6c2ff55f */
    118 printf("UUID=%.8s" "-%.4s-%.4s-%.4s-%.12s\n",
    119 uuid_string,
    120 uuid_string+8,
    121 uuid_string+8+4,
    122 uuid_string+8+4+4,
    123 uuid_string+8+4+4+4
    124 );
    125 }
    126 safe_strncpy(hdr->sws_volume, label, 16);
    127
    128 /* Write the header. Sync to disk because some kernel versions check
    129 * signature on disk (not in cache) during swapon. */
    130 xlseek(fd, 1024, SEEK_SET);
    131 xwrite(fd, hdr, NWORDS * 4);
    132 xlseek(fd, pagesize - 10, SEEK_SET);
    133 xwrite(fd, SWAPSPACE2, 10);
    134 fsync(fd);
    135
    136 if (ENABLE_FEATURE_CLEAN_UP)
    137 close(fd);
    138
    139 return 0;
    140 }