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

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    Revision 984 - (hide annotations) (download)
    Sun May 30 11:32:42 2010 UTC (14 years 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 niro 532 /* 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 niro 816 #include "libbb.h"
    9 niro 532
    10 niro 816 #if ENABLE_SELINUX
    11     static void mkswap_selinux_setcontext(int fd, const char *path)
    12 niro 532 {
    13 niro 816 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 niro 984 # define mkswap_selinux_setcontext(fd, path) ((void)0)
    51 niro 816 #endif
    52    
    53 niro 984 /* from Linux 2.6.23 */
    54 niro 816 /*
    55 niro 984 * Magic header for a swap area. ... Note that the first
    56     * kilobyte is reserved for boot loader or disk label stuff.
    57 niro 816 */
    58 niro 984 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 niro 816 };
    69    
    70     #define NWORDS 129
    71 niro 984 #define hdr ((struct swap_header_v1*)bb_common_bufsiz1)
    72 niro 816
    73 niro 984 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 niro 816 };
    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 niro 984 int mkswap_main(int argc UNUSED_PARAM, char **argv)
    83 niro 816 {
    84 niro 984 int fd;
    85     unsigned pagesize;
    86 niro 532 off_t len;
    87 niro 984 const char *label = "";
    88 niro 532
    89 niro 984 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 niro 532
    96 niro 984 fd = xopen(argv[0], O_WRONLY);
    97 niro 532
    98 niro 984 /* Figure out how big the device is and announce our intentions */
    99 niro 816 /* fdlength was reported to be unreliable - use seek */
    100     len = xlseek(fd, 0, SEEK_END);
    101 niro 984 if (ENABLE_SELINUX)
    102     xlseek(fd, 0, SEEK_SET);
    103    
    104 niro 532 pagesize = getpagesize();
    105 niro 984 len -= pagesize;
    106     printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len);
    107     mkswap_selinux_setcontext(fd, argv[0]);
    108 niro 532
    109 niro 984 /* Make a header. hdr is zero-filled so far... */
    110     hdr->version = 1;
    111     hdr->last_page = (uoff_t)len / pagesize;
    112 niro 532
    113 niro 984 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 niro 532
    128 niro 984 /* Write the header. Sync to disk because some kernel versions check
    129     * signature on disk (not in cache) during swapon. */
    130 niro 532 xlseek(fd, 1024, SEEK_SET);
    131 niro 816 xwrite(fd, hdr, NWORDS * 4);
    132     xlseek(fd, pagesize - 10, SEEK_SET);
    133     xwrite(fd, SWAPSPACE2, 10);
    134 niro 532 fsync(fd);
    135    
    136 niro 984 if (ENABLE_FEATURE_CLEAN_UP)
    137     close(fd);
    138 niro 532
    139     return 0;
    140     }