blob: b5d2c49b6b0e9fd8c1f50e5639b7f36b3c5adaff
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 |
18 | static 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 | */ |
64 | struct 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 | |
79 | struct 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 */ |
85 | static const char SWAPSPACE2[sizeof("SWAPSPACE2")-1] ALIGN1 = "SWAPSPACE2"; |
86 | |
87 | int mkswap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
88 | int 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 | } |
150 |