1 /* cpio.c - a basic cpio 2 * 3 * Written 2013 AD by Isaac Dunham; this code is placed under the 4 * same license as toybox or as CC0, at your option. 5 * 6 * http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/cpio.html 7 * and http://pubs.opengroup.org/onlinepubs/7908799/xcu/cpio.html 8 * 9 * Yes, that's SUSv2, the newer standards removed it around the time RPM 10 * and initramfs started heavily using this archive format. 11 * 12 * Modern cpio expanded header to 110 bytes (first field 6 bytes, rest are 8). 13 * In order: magic ino mode uid gid nlink mtime filesize devmajor devminor 14 * rdevmajor rdevminor namesize check 15 16 USE_CPIO(NEWTOY(cpio, "mduH:p:|i|t|F:v(verbose)o|[!pio][!pot][!pF]", TOYFLAG_BIN)) 17 18 config CPIO 19 bool "cpio" 20 default y 21 help 22 usage: cpio -{o|t|i|p DEST} [-v] [--verbose] [-F FILE] [ignored: -mdu -H newc] 23 24 copy files into and out of a "newc" format cpio archive 25 26 -F FILE use archive FILE instead of stdin/stdout 27 -p DEST copy-pass mode, copy stdin file list to directory DEST 28 -i extract from archive into file system (stdin=archive) 29 -o create archive (stdin=list of files, stdout=archive) 30 -t test files (list only, stdin=archive, stdout=list of files) 31 -v verbose (list files during create/extract) 32 */ 33 34 #define FOR_cpio 35 #include "toys.h" 36 37 GLOBALS( 38 char *archive; 39 char *pass; 40 char *fmt; 41 ) 42 43 // Read strings, tail padded to 4 byte alignment. Argument "align" is amount 44 // by which start of string isn't aligned (usually 0, but header is 110 bytes 45 // which is 2 bytes off because the first field wasn't expanded from 6 to 8). 46 static char *strpad(int fd, unsigned len, unsigned align) 47 { 48 char *str; 49 50 align = (align + len) & 3; 51 if (align) len += (4-align); 52 xreadall(fd, str = xmalloc(len+1), len); 53 str[len]=0; // redundant, in case archive is bad 54 55 return str; 56 } 57 58 //convert hex to uint; mostly to allow using bits of non-terminated strings 59 unsigned x8u(char *hex) 60 { 61 unsigned val, inpos = 8, outpos; 62 char pattern[6]; 63 64 while (*hex == '0') { 65 hex++; 66 if (!--inpos) return 0; 67 } 68 // Because scanf gratuitously treats %*X differently than printf does. 69 sprintf(pattern, "%%%dX%%n", inpos); 70 sscanf(hex, pattern, &val, &outpos); 71 if (inpos != outpos) error_exit("bad header"); 72 73 return val; 74 } 75 76 void cpio_main(void) 77 { 78 // Subtle bit: FLAG_o is 1 so we can just use it to select stdin/stdout. 79 int pipe, afd = toys.optflags & FLAG_o; 80 pid_t pid = 0; 81 82 // In passthrough mode, parent stays in original dir and generates archive 83 // to pipe, child does chdir to new dir and reads archive from stdin (pipe). 84 if (TT.pass) { 85 if (!(pid = xpopen(0, &pipe, 0))) { 86 toys.optflags |= FLAG_i; 87 xchdir(TT.pass); 88 } else { 89 toys.optflags |= FLAG_o; 90 afd = pipe; 91 } 92 } 93 94 if (TT.archive) { 95 int perm = (toys.optflags & FLAG_o) ? O_CREAT|O_WRONLY|O_TRUNC : O_RDONLY; 96 97 afd = xcreate(TT.archive, perm, 0644); 98 } 99 100 // read cpio archive 101 102 if (toys.optflags & (FLAG_i|FLAG_t)) for (;;) { 103 char *name, *tofree, *data; 104 unsigned size, mode, uid, gid, timestamp; 105 int test = toys.optflags & FLAG_t, err = 0; 106 107 // Read header and name. 108 xreadall(afd, toybuf, 110); 109 tofree = name = strpad(afd, x8u(toybuf+94), 110); 110 if (!strcmp("TRAILER!!!", name)) { 111 if (CFG_TOYBOX_FREE) free(tofree); 112 break; 113 } 114 115 // If you want to extract absolute paths, "cd /" and run cpio. 116 while (*name == '/') name++; 117 // TODO: remove .. entries 118 119 size = x8u(toybuf+54); 120 mode = x8u(toybuf+14); 121 uid = x8u(toybuf+30); 122 gid = x8u(toybuf+38); 123 timestamp = x8u(toybuf+46); // unsigned 32 bit, so year 2100 problem 124 125 if (toys.optflags & (FLAG_t|FLAG_v)) puts(name); 126 127 if (!test && strrchr(name, '/') && mkpathat(AT_FDCWD, name, 0, 2)) { 128 perror_msg("mkpath '%s'", name); 129 test++; 130 } 131 132 // Consume entire record even if it couldn't create file, so we're 133 // properly aligned with next file. 134 135 if (S_ISDIR(mode)) { 136 if (!test) err = mkdir(name, mode); 137 } else if (S_ISLNK(mode)) { 138 data = strpad(afd, size, 0); 139 if (!test) err = symlink(data, name); 140 free(data); 141 // Can't get a filehandle to a symlink, so do special chown 142 if (!err && !getpid()) err = lchown(name, uid, gid); 143 } else if (S_ISREG(mode)) { 144 int fd = test ? 0 : open(name, O_CREAT|O_WRONLY|O_TRUNC|O_NOFOLLOW, mode); 145 146 // If write fails, we still need to read/discard data to continue with 147 // archive. Since doing so overwrites errno, report error now 148 if (fd < 0) { 149 perror_msg("create %s", name); 150 test++; 151 } 152 153 data = toybuf; 154 while (size) { 155 if (size < sizeof(toybuf)) data = strpad(afd, size, 0); 156 else xreadall(afd, toybuf, sizeof(toybuf)); 157 if (!test) xwrite(fd, data, data == toybuf ? sizeof(toybuf) : size); 158 if (data != toybuf) { 159 free(data); 160 break; 161 } 162 size -= sizeof(toybuf); 163 } 164 165 if (!test) { 166 // set owner, restore dropped suid bit 167 if (!getpid()) { 168 err = fchown(fd, uid, gid); 169 if (!err) err = fchmod(fd, mode); 170 } 171 close(fd); 172 } 173 } else if (!test) 174 err = mknod(name, mode, makedev(x8u(toybuf+62), x8u(toybuf+70))); 175 176 // Set ownership and timestamp. 177 if (!test && !err) { 178 // Creading dir/dev doesn't give us a filehandle, we have to refer to it 179 // by name to chown/utime, but how do we know it's the same item? 180 // Check that we at least have the right type of entity open, and do 181 // NOT restore dropped suid bit in this case. 182 if (!S_ISREG(mode) && !S_ISLNK(mode) && !getpid()) { 183 int fd = open(name, O_WRONLY|O_NOFOLLOW); 184 struct stat st; 185 186 if (fd != -1 && !fstat(fd, &st) && (st.st_mode&S_IFMT) == mode) 187 err = fchown(fd, uid, gid); 188 else err = 1; 189 190 close(fd); 191 } 192 193 // set timestamp 194 if (!err) { 195 struct timespec times[2]; 196 197 memset(times, 0, sizeof(struct timespec)*2); 198 times[0].tv_sec = times[1].tv_sec = timestamp; 199 err = utimensat(AT_FDCWD, name, times, AT_SYMLINK_NOFOLLOW); 200 } 201 } 202 203 if (err) perror_msg("'%s'", name); 204 free(tofree); 205 206 // Output cpio archive 207 208 } else { 209 char *name = 0; 210 size_t size = 0; 211 212 for (;;) { 213 struct stat st; 214 unsigned nlen, error = 0, zero = 0; 215 int len, fd = -1; 216 ssize_t llen; 217 218 len = getline(&name, &size, stdin); 219 if (len<1) break; 220 if (name[len-1] == '\n') name[--len] = 0; 221 nlen = len+1; 222 if (lstat(name, &st) || (S_ISREG(st.st_mode) 223 && st.st_size && (fd = open(name, O_RDONLY))<0)) 224 { 225 perror_msg("%s", name); 226 continue; 227 } 228 229 if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode)) st.st_size = 0; 230 if (st.st_size >> 32) perror_msg("skipping >2G file '%s'", name); 231 else { 232 llen = sprintf(toybuf, 233 "070701%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X", 234 (int)st.st_ino, st.st_mode, st.st_uid, st.st_gid, (int)st.st_nlink, 235 (int)st.st_mtime, (int)st.st_size, major(st.st_dev), 236 minor(st.st_dev), major(st.st_rdev), minor(st.st_rdev), nlen, 0); 237 xwrite(afd, toybuf, llen); 238 xwrite(afd, name, nlen); 239 240 // NUL Pad header up to 4 multiple bytes. 241 llen = (llen + nlen) & 3; 242 if (llen) xwrite(afd, &zero, 4-llen); 243 244 // Write out body for symlink or regular file 245 llen = st.st_size; 246 if (S_ISLNK(st.st_mode)) { 247 if (readlink(name, toybuf, sizeof(toybuf)-1) == llen) 248 xwrite(afd, toybuf, llen); 249 else perror_msg("readlink '%s'", name); 250 } else while (llen) { 251 nlen = llen > sizeof(toybuf) ? sizeof(toybuf) : llen; 252 llen -= nlen; 253 // If read fails, write anyway (already wrote size in header) 254 if (nlen != readall(fd, toybuf, nlen)) 255 if (!error++) perror_msg("bad read from file '%s'", name); 256 xwrite(afd, toybuf, nlen); 257 } 258 llen = st.st_size & 3; 259 if (llen) xwrite(afd, &zero, 4-llen); 260 } 261 close(fd); 262 } 263 free(name); 264 265 memset(toybuf, 0, sizeof(toybuf)); 266 xwrite(afd, toybuf, 267 sprintf(toybuf, "070701%040X%056X%08XTRAILER!!!", 1, 0x0b, 0)+4); 268 } 269 if (TT.archive) xclose(afd); 270 271 if (TT.pass) toys.exitval |= xpclose(pid, pipe); 272 } 273
