lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 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 | } |