Contents of /tags/mkinitrd-6_5_1/busybox/util-linux/mkswap.c
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Wed Sep 7 17:51:16 2011 UTC (13 years ago) by niro
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File size: 3635 byte(s)
Wed Sep 7 17:51:16 2011 UTC (13 years ago) by niro
File MIME type: text/plain
File size: 3635 byte(s)
tagged 'mkinitrd-6_5_1'
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 | } FIX_ALIASING; |
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"; /* at least one param */ |
90 | /* TODO: -p PAGESZ, -U UUID */ |
91 | getopt32(argv, "L:", &label); |
92 | argv += optind; |
93 | |
94 | fd = xopen(argv[0], O_WRONLY); |
95 | |
96 | /* Figure out how big the device is */ |
97 | len = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ 1); |
98 | pagesize = getpagesize(); |
99 | len -= pagesize; |
100 | |
101 | /* Announce our intentions */ |
102 | printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len); |
103 | mkswap_selinux_setcontext(fd, argv[0]); |
104 | |
105 | /* Make a header. hdr is zero-filled so far... */ |
106 | hdr->version = 1; |
107 | hdr->last_page = (uoff_t)len / pagesize; |
108 | |
109 | if (ENABLE_FEATURE_MKSWAP_UUID) { |
110 | char uuid_string[32]; |
111 | generate_uuid((void*)hdr->sws_uuid); |
112 | bin2hex(uuid_string, hdr->sws_uuid, 16); |
113 | /* f.e. UUID=dfd9c173-be52-4d27-99a5-c34c6c2ff55f */ |
114 | printf("UUID=%.8s" "-%.4s-%.4s-%.4s-%.12s\n", |
115 | uuid_string, |
116 | uuid_string+8, |
117 | uuid_string+8+4, |
118 | uuid_string+8+4+4, |
119 | uuid_string+8+4+4+4 |
120 | ); |
121 | } |
122 | safe_strncpy(hdr->sws_volume, label, 16); |
123 | |
124 | /* Write the header. Sync to disk because some kernel versions check |
125 | * signature on disk (not in cache) during swapon. */ |
126 | xlseek(fd, 1024, SEEK_SET); |
127 | xwrite(fd, hdr, NWORDS * 4); |
128 | xlseek(fd, pagesize - 10, SEEK_SET); |
129 | xwrite(fd, SWAPSPACE2, 10); |
130 | fsync(fd); |
131 | |
132 | if (ENABLE_FEATURE_CLEAN_UP) |
133 | close(fd); |
134 | |
135 | return 0; |
136 | } |