Contents of /tags/mkinitrd-6_1_12/busybox/util-linux/mkswap.c
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Tue Nov 17 21:24:51 2009 UTC (14 years, 10 months ago) by niro
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File size: 3464 byte(s)
Tue Nov 17 21:24:51 2009 UTC (14 years, 10 months ago) by niro
File MIME type: text/plain
File size: 3464 byte(s)
tagged 'mkinitrd-6_1_12'
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 | |
9 | #include "libbb.h" |
10 | |
11 | #if ENABLE_SELINUX |
12 | static void mkswap_selinux_setcontext(int fd, const char *path) |
13 | { |
14 | struct stat stbuf; |
15 | |
16 | if (!is_selinux_enabled()) |
17 | return; |
18 | |
19 | if (fstat(fd, &stbuf) < 0) |
20 | bb_perror_msg_and_die("fstat failed"); |
21 | if (S_ISREG(stbuf.st_mode)) { |
22 | security_context_t newcon; |
23 | security_context_t oldcon = NULL; |
24 | context_t context; |
25 | |
26 | if (fgetfilecon(fd, &oldcon) < 0) { |
27 | if (errno != ENODATA) |
28 | goto error; |
29 | if (matchpathcon(path, stbuf.st_mode, &oldcon) < 0) |
30 | goto error; |
31 | } |
32 | context = context_new(oldcon); |
33 | if (!context || context_type_set(context, "swapfile_t")) |
34 | goto error; |
35 | newcon = context_str(context); |
36 | if (!newcon) |
37 | goto error; |
38 | /* fsetfilecon_raw is hidden */ |
39 | if (strcmp(oldcon, newcon) != 0 && fsetfilecon(fd, newcon) < 0) |
40 | goto error; |
41 | if (ENABLE_FEATURE_CLEAN_UP) { |
42 | context_free(context); |
43 | freecon(oldcon); |
44 | } |
45 | } |
46 | return; |
47 | error: |
48 | bb_perror_msg_and_die("SELinux relabeling failed"); |
49 | } |
50 | #else |
51 | #define mkswap_selinux_setcontext(fd, path) ((void)0) |
52 | #endif |
53 | |
54 | #if 0 /* from Linux 2.6.23 */ |
55 | /* |
56 | * Magic header for a swap area. The first part of the union is |
57 | * what the swap magic looks like for the old (limited to 128MB) |
58 | * swap area format, the second part of the union adds - in the |
59 | * old reserved area - some extra information. Note that the first |
60 | * kilobyte is reserved for boot loader or disk label stuff... |
61 | */ |
62 | union swap_header { |
63 | struct { |
64 | char reserved[PAGE_SIZE - 10]; |
65 | char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */ |
66 | } magic; |
67 | struct { |
68 | char bootbits[1024]; /* Space for disklabel etc. */ |
69 | __u32 version; /* second kbyte, word 0 */ |
70 | __u32 last_page; /* 1 */ |
71 | __u32 nr_badpages; /* 2 */ |
72 | unsigned char sws_uuid[16]; /* 3,4,5,6 */ |
73 | unsigned char sws_volume[16]; /* 7,8,9,10 */ |
74 | __u32 padding[117]; /* 11..127 */ |
75 | __u32 badpages[1]; /* 128, total 129 32-bit words */ |
76 | } info; |
77 | }; |
78 | #endif |
79 | |
80 | #define NWORDS 129 |
81 | #define hdr ((uint32_t*)(&bb_common_bufsiz1)) |
82 | |
83 | struct BUG_bufsiz1_is_too_small { |
84 | char BUG_bufsiz1_is_too_small[COMMON_BUFSIZE < (NWORDS * 4) ? -1 : 1]; |
85 | }; |
86 | |
87 | /* Stored without terminating NUL */ |
88 | static const char SWAPSPACE2[sizeof("SWAPSPACE2")-1] ALIGN1 = "SWAPSPACE2"; |
89 | |
90 | int mkswap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
91 | int mkswap_main(int argc, char **argv) |
92 | { |
93 | int fd, pagesize; |
94 | off_t len; |
95 | |
96 | // No options supported. |
97 | |
98 | if (argc != 2) bb_show_usage(); |
99 | |
100 | // Figure out how big the device is and announce our intentions. |
101 | |
102 | fd = xopen(argv[1], O_RDWR); |
103 | /* fdlength was reported to be unreliable - use seek */ |
104 | len = xlseek(fd, 0, SEEK_END); |
105 | #if ENABLE_SELINUX |
106 | xlseek(fd, 0, SEEK_SET); |
107 | #endif |
108 | pagesize = getpagesize(); |
109 | printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", |
110 | len - pagesize); |
111 | mkswap_selinux_setcontext(fd, argv[1]); |
112 | |
113 | // Make a header. hdr is zero-filled so far... |
114 | hdr[0] = 1; |
115 | hdr[1] = (len / pagesize) - 1; |
116 | |
117 | // Write the header. Sync to disk because some kernel versions check |
118 | // signature on disk (not in cache) during swapon. |
119 | |
120 | xlseek(fd, 1024, SEEK_SET); |
121 | xwrite(fd, hdr, NWORDS * 4); |
122 | xlseek(fd, pagesize - 10, SEEK_SET); |
123 | xwrite(fd, SWAPSPACE2, 10); |
124 | fsync(fd); |
125 | |
126 | if (ENABLE_FEATURE_CLEAN_UP) close(fd); |
127 | |
128 | return 0; |
129 | } |