source: branches/3.2/mindi-busybox/util-linux/mkswap.c @ 3232

Last change on this file since 3232 was 3232, checked in by Bruno Cornec, 7 years ago
  • Update mindi-busybox to 1.21.1
File size: 3.9 KB
Line 
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 GPLv2, see file LICENSE in this source tree.
7 */
8
9//usage:#define mkswap_trivial_usage
10//usage:       "[-L LBL] BLOCKDEV [KBYTES]"
11//usage:#define mkswap_full_usage "\n\n"
12//usage:       "Prepare BLOCKDEV to be used as swap partition\n"
13//usage:     "\n    -L LBL  Label"
14
15#include "libbb.h"
16
17#if ENABLE_SELINUX
18static void mkswap_selinux_setcontext(int fd, const char *path)
19{
20    struct stat stbuf;
21
22    if (!is_selinux_enabled())
23        return;
24
25    xfstat(fd, &stbuf, path);
26    if (S_ISREG(stbuf.st_mode)) {
27        security_context_t newcon;
28        security_context_t oldcon = NULL;
29        context_t context;
30
31        if (fgetfilecon(fd, &oldcon) < 0) {
32            if (errno != ENODATA)
33                goto error;
34            if (matchpathcon(path, stbuf.st_mode, &oldcon) < 0)
35                goto error;
36        }
37        context = context_new(oldcon);
38        if (!context || context_type_set(context, "swapfile_t"))
39            goto error;
40        newcon = context_str(context);
41        if (!newcon)
42            goto error;
43        /* fsetfilecon_raw is hidden */
44        if (strcmp(oldcon, newcon) != 0 && fsetfilecon(fd, newcon) < 0)
45            goto error;
46        if (ENABLE_FEATURE_CLEAN_UP) {
47            context_free(context);
48            freecon(oldcon);
49        }
50    }
51    return;
52 error:
53    bb_perror_msg_and_die("SELinux relabeling failed");
54}
55#else
56# define mkswap_selinux_setcontext(fd, path) ((void)0)
57#endif
58
59/* from Linux 2.6.23 */
60/*
61 * Magic header for a swap area. ... Note that the first
62 * kilobyte is reserved for boot loader or disk label stuff.
63 */
64struct swap_header_v1 {
65/*  char     bootbits[1024];    Space for disklabel etc. */
66    uint32_t version;        /* second kbyte, word 0 */
67    uint32_t last_page;      /* 1 */
68    uint32_t nr_badpages;    /* 2 */
69    char     sws_uuid[16];   /* 3,4,5,6 */
70    char     sws_volume[16]; /* 7,8,9,10 */
71    uint32_t padding[117];   /* 11..127 */
72    uint32_t badpages[1];    /* 128 */
73    /* total 129 32-bit words in 2nd kilobyte */
74} FIX_ALIASING;
75
76#define NWORDS 129
77#define hdr ((struct swap_header_v1*)bb_common_bufsiz1)
78
79struct BUG_sizes {
80    char swap_header_v1_wrong[sizeof(*hdr)  != (NWORDS * 4) ? -1 : 1];
81    char bufsiz1_is_too_small[COMMON_BUFSIZE < (NWORDS * 4) ? -1 : 1];
82};
83
84/* Stored without terminating NUL */
85static const char SWAPSPACE2[sizeof("SWAPSPACE2")-1] ALIGN1 = "SWAPSPACE2";
86
87int mkswap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
88int mkswap_main(int argc UNUSED_PARAM, char **argv)
89{
90    int fd;
91    unsigned pagesize;
92    off_t len;
93    const char *label = "";
94
95    opt_complementary = "-1"; /* at least one param */
96    /* TODO: -p PAGESZ, -U UUID */
97    getopt32(argv, "L:", &label);
98    argv += optind;
99
100    fd = xopen(argv[0], O_WRONLY);
101
102    /* Figure out how big the device is */
103    len = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ 1);
104    pagesize = getpagesize();
105    len -= pagesize;
106
107    /* Announce our intentions */
108    printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len);
109    mkswap_selinux_setcontext(fd, argv[0]);
110
111    /* hdr is zero-filled so far. Clear the first kbyte, or else
112     * mkswap-ing former FAT partition does NOT erase its signature.
113     *
114     * util-linux-ng 2.17.2 claims to erase it only if it does not see
115     * a partition table and is not run on whole disk. -f forces it.
116     */
117    xwrite(fd, hdr, 1024);
118
119    /* Fill the header. */
120    hdr->version = 1;
121    hdr->last_page = (uoff_t)len / pagesize;
122
123    if (ENABLE_FEATURE_MKSWAP_UUID) {
124        char uuid_string[32];
125        generate_uuid((void*)hdr->sws_uuid);
126        bin2hex(uuid_string, hdr->sws_uuid, 16);
127        /* f.e. UUID=dfd9c173-be52-4d27-99a5-c34c6c2ff55f */
128        printf("UUID=%.8s"  "-%.4s-%.4s-%.4s-%.12s\n",
129            uuid_string,
130            uuid_string+8,
131            uuid_string+8+4,
132            uuid_string+8+4+4,
133            uuid_string+8+4+4+4
134        );
135    }
136    safe_strncpy(hdr->sws_volume, label, 16);
137
138    /* Write the header.  Sync to disk because some kernel versions check
139     * signature on disk (not in cache) during swapon. */
140    xwrite(fd, hdr, NWORDS * 4);
141    xlseek(fd, pagesize - 10, SEEK_SET);
142    xwrite(fd, SWAPSPACE2, 10);
143    fsync(fd);
144
145    if (ENABLE_FEATURE_CLEAN_UP)
146        close(fd);
147
148    return 0;
149}
Note: See TracBrowser for help on using the repository browser.