1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
/* vi: set sw=4 ts=4: */
/* mkswap.c - format swap device (Linux v1 only)
*
* Copyright 2006 Rob Landley <rob@landley.net>
*
* Licensed under GPL version 2, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
#if ENABLE_SELINUX
static void mkswap_selinux_setcontext(int fd, const char *path)
{
struct stat stbuf;
if (!is_selinux_enabled())
return;
if (fstat(fd, &stbuf) < 0)
bb_perror_msg_and_die("fstat failed");
if (S_ISREG(stbuf.st_mode)) {
security_context_t newcon;
security_context_t oldcon = NULL;
context_t context;
if (fgetfilecon(fd, &oldcon) < 0) {
if (errno != ENODATA)
goto error;
if (matchpathcon(path, stbuf.st_mode, &oldcon) < 0)
goto error;
}
context = context_new(oldcon);
if (!context || context_type_set(context, "swapfile_t"))
goto error;
newcon = context_str(context);
if (!newcon)
goto error;
/* fsetfilecon_raw is hidden */
if (strcmp(oldcon, newcon) != 0 && fsetfilecon(fd, newcon) < 0)
goto error;
if (ENABLE_FEATURE_CLEAN_UP) {
context_free(context);
freecon(oldcon);
}
}
return;
error:
bb_perror_msg_and_die("SELinux relabeling failed");
}
#else
# define mkswap_selinux_setcontext(fd, path) ((void)0)
#endif
/* from Linux 2.6.23 */
/*
* Magic header for a swap area. ... Note that the first
* kilobyte is reserved for boot loader or disk label stuff.
*/
struct swap_header_v1 {
/* char bootbits[1024]; Space for disklabel etc. */
uint32_t version; /* second kbyte, word 0 */
uint32_t last_page; /* 1 */
uint32_t nr_badpages; /* 2 */
char sws_uuid[16]; /* 3,4,5,6 */
char sws_volume[16]; /* 7,8,9,10 */
uint32_t padding[117]; /* 11..127 */
uint32_t badpages[1]; /* 128 */
/* total 129 32-bit words in 2nd kilobyte */
};
#define NWORDS 129
#define hdr ((struct swap_header_v1*)bb_common_bufsiz1)
struct BUG_sizes {
char swap_header_v1_wrong[sizeof(*hdr) != (NWORDS * 4) ? -1 : 1];
char bufsiz1_is_too_small[COMMON_BUFSIZE < (NWORDS * 4) ? -1 : 1];
};
/* Stored without terminating NUL */
static const char SWAPSPACE2[sizeof("SWAPSPACE2")-1] ALIGN1 = "SWAPSPACE2";
int mkswap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int mkswap_main(int argc UNUSED_PARAM, char **argv)
{
int fd;
unsigned pagesize;
off_t len;
const char *label = "";
opt_complementary = "-1"; /* at least one param */
/* TODO: -p PAGESZ, -U UUID */
getopt32(argv, "L:", &label);
argv += optind;
fd = xopen(argv[0], O_WRONLY);
/* Figure out how big the device is */
len = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ 1);
pagesize = getpagesize();
len -= pagesize;
/* Announce our intentions */
printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len);
mkswap_selinux_setcontext(fd, argv[0]);
/* Make a header. hdr is zero-filled so far... */
hdr->version = 1;
hdr->last_page = (uoff_t)len / pagesize;
if (ENABLE_FEATURE_MKSWAP_UUID) {
char uuid_string[32];
generate_uuid((void*)hdr->sws_uuid);
bin2hex(uuid_string, hdr->sws_uuid, 16);
/* f.e. UUID=dfd9c173-be52-4d27-99a5-c34c6c2ff55f */
printf("UUID=%.8s" "-%.4s-%.4s-%.4s-%.12s\n",
uuid_string,
uuid_string+8,
uuid_string+8+4,
uuid_string+8+4+4,
uuid_string+8+4+4+4
);
}
safe_strncpy(hdr->sws_volume, label, 16);
/* Write the header. Sync to disk because some kernel versions check
* signature on disk (not in cache) during swapon. */
xlseek(fd, 1024, SEEK_SET);
xwrite(fd, hdr, NWORDS * 4);
xlseek(fd, pagesize - 10, SEEK_SET);
xwrite(fd, SWAPSPACE2, 10);
fsync(fd);
if (ENABLE_FEATURE_CLEAN_UP)
close(fd);
return 0;
}
|
