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 * Portions Copyright 2015 by Frontier Silicon Ltd. 7 * 8 * http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/cpio.html 9 * and http://pubs.opengroup.org/onlinepubs/7908799/xcu/cpio.html 10 * 11 * Yes, that's SUSv2, the newer standards removed it around the time RPM 12 * and initramfs started heavily using this archive format. 13 * 14 * Modern cpio expanded header to 110 bytes (first field 6 bytes, rest are 8). 15 * In order: magic ino mode uid gid nlink mtime filesize devmajor devminor 16 * rdevmajor rdevminor namesize check 17 * This is the equiavlent of mode -H newc when using GNU CPIO. 18 19 USE_CPIO(NEWTOY(cpio, "(no-preserve-owner)mduH:p:|i|t|F:v(verbose)o|[!pio][!pot][!pF]", TOYFLAG_BIN)) 20 21 config CPIO 22 bool "cpio" 23 default y 24 help 25 usage: cpio -{o|t|i|p DEST} [-v] [--verbose] [-F FILE] [--no-preserve-owner] 26 [ignored: -mdu -H newc] 27 28 copy files into and out of a "newc" format cpio archive 29 30 -F FILE use archive FILE instead of stdin/stdout 31 -p DEST copy-pass mode, copy stdin file list to directory DEST 32 -i extract from archive into file system (stdin=archive) 33 -o create archive (stdin=list of files, stdout=archive) 34 -t test files (list only, stdin=archive, stdout=list of files) 35 -v verbose (list files during create/extract) 36 --no-preserve-owner (don't set ownership during extract) 37 */ 38 39 #define FOR_cpio 40 #include "toys.h" 41 42 GLOBALS( 43 char *archive; 44 char *pass; 45 char *fmt; 46 ) 47 48 // Read strings, tail padded to 4 byte alignment. Argument "align" is amount 49 // by which start of string isn't aligned (usually 0, but header is 110 bytes 50 // which is 2 bytes off because the first field wasn't expanded from 6 to 8). 51 static char *strpad(int fd, unsigned len, unsigned align) 52 { 53 char *str; 54 55 align = (align + len) & 3; 56 if (align) len += (4-align); 57 xreadall(fd, str = xmalloc(len+1), len); 58 str[len]=0; // redundant, in case archive is bad 59 60 return str; 61 } 62 63 //convert hex to uint; mostly to allow using bits of non-terminated strings 64 unsigned x8u(char *hex) 65 { 66 unsigned val, inpos = 8, outpos; 67 char pattern[6]; 68 69 while (*hex == '0') { 70 hex++; 71 if (!--inpos) return 0; 72 } 73 // Because scanf gratuitously treats %*X differently than printf does. 74 sprintf(pattern, "%%%dX%%n", inpos); 75 sscanf(hex, pattern, &val, &outpos); 76 if (inpos != outpos) error_exit("bad header"); 77 78 return val; 79 } 80 81 void cpio_main(void) 82 { 83 // Subtle bit: FLAG_o is 1 so we can just use it to select stdin/stdout. 84 int pipe, afd = toys.optflags & FLAG_o; 85 pid_t pid = 0; 86 87 // In passthrough mode, parent stays in original dir and generates archive 88 // to pipe, child does chdir to new dir and reads archive from stdin (pipe). 89 if (TT.pass) { 90 if (toys.stacktop) { 91 // xpopen() doesn't return from child due to vfork(), instead restarts 92 // with !toys.stacktop 93 pid = xpopen(0, &pipe, 0); 94 afd = pipe; 95 } else { 96 // child 97 toys.optflags |= FLAG_i; 98 xchdir(TT.pass); 99 } 100 } 101 102 if (TT.archive) { 103 int perm = (toys.optflags & FLAG_o) ? O_CREAT|O_WRONLY|O_TRUNC : O_RDONLY; 104 105 afd = xcreate(TT.archive, perm, 0644); 106 } 107 108 // read cpio archive 109 110 if (toys.optflags & (FLAG_i|FLAG_t)) for (;;) { 111 char *name, *tofree, *data; 112 unsigned size, mode, uid, gid, timestamp; 113 int test = toys.optflags & FLAG_t, err = 0; 114 115 // Read header and name. 116 xreadall(afd, toybuf, 110); 117 tofree = name = strpad(afd, x8u(toybuf+94), 110); 118 if (!strcmp("TRAILER!!!", name)) { 119 if (CFG_TOYBOX_FREE) free(tofree); 120 break; 121 } 122 123 // If you want to extract absolute paths, "cd /" and run cpio. 124 while (*name == '/') name++; 125 // TODO: remove .. entries 126 127 size = x8u(toybuf+54); 128 mode = x8u(toybuf+14); 129 uid = x8u(toybuf+22); 130 gid = x8u(toybuf+30); 131 timestamp = x8u(toybuf+46); // unsigned 32 bit, so year 2100 problem 132 133 if (toys.optflags & (FLAG_t|FLAG_v)) puts(name); 134 135 if (!test && strrchr(name, '/') && mkpathat(AT_FDCWD, name, 0, 2)) { 136 perror_msg("mkpath '%s'", name); 137 test++; 138 } 139 140 // Consume entire record even if it couldn't create file, so we're 141 // properly aligned with next file. 142 143 if (S_ISDIR(mode)) { 144 if (!test) err = mkdir(name, mode); 145 } else if (S_ISLNK(mode)) { 146 data = strpad(afd, size, 0); 147 if (!test) err = symlink(data, name); 148 free(data); 149 // Can't get a filehandle to a symlink, so do special chown 150 if (!err && !geteuid() && !(toys.optflags & FLAG_no_preserve_owner)) 151 err = lchown(name, uid, gid); 152 } else if (S_ISREG(mode)) { 153 int fd = test ? 0 : open(name, O_CREAT|O_WRONLY|O_TRUNC|O_NOFOLLOW, mode); 154 155 // If write fails, we still need to read/discard data to continue with 156 // archive. Since doing so overwrites errno, report error now 157 if (fd < 0) { 158 perror_msg("create %s", name); 159 test++; 160 } 161 162 data = toybuf; 163 while (size) { 164 if (size < sizeof(toybuf)) data = strpad(afd, size, 0); 165 else xreadall(afd, toybuf, sizeof(toybuf)); 166 if (!test) xwrite(fd, data, data == toybuf ? sizeof(toybuf) : size); 167 if (data != toybuf) { 168 free(data); 169 break; 170 } 171 size -= sizeof(toybuf); 172 } 173 174 if (!test) { 175 // set owner, restore dropped suid bit 176 if (!geteuid() && !(toys.optflags & FLAG_no_preserve_owner)) { 177 err = fchown(fd, uid, gid); 178 if (!err) err = fchmod(fd, mode); 179 } 180 close(fd); 181 } 182 } else if (!test) 183 err = mknod(name, mode, makedev(x8u(toybuf+78), x8u(toybuf+86))); 184 185 // Set ownership and timestamp. 186 if (!test && !err) { 187 // Creading dir/dev doesn't give us a filehandle, we have to refer to it 188 // by name to chown/utime, but how do we know it's the same item? 189 // Check that we at least have the right type of entity open, and do 190 // NOT restore dropped suid bit in this case. 191 if (!S_ISREG(mode) && !S_ISLNK(mode) && !geteuid() 192 && !(toys.optflags & FLAG_no_preserve_owner)) 193 { 194 int fd = open(name, O_RDONLY|O_NOFOLLOW); 195 struct stat st; 196 197 if (fd != -1 && !fstat(fd, &st) && (st.st_mode&S_IFMT) == (mode&S_IFMT)) 198 err = fchown(fd, uid, gid); 199 else err = 1; 200 201 close(fd); 202 } 203 204 // set timestamp 205 if (!err) { 206 struct timespec times[2]; 207 208 memset(times, 0, sizeof(struct timespec)*2); 209 times[0].tv_sec = times[1].tv_sec = timestamp; 210 err = utimensat(AT_FDCWD, name, times, AT_SYMLINK_NOFOLLOW); 211 } 212 } 213 214 if (err) perror_msg_raw(name); 215 free(tofree); 216 217 // Output cpio archive 218 219 } else { 220 char *name = 0; 221 size_t size = 0; 222 223 for (;;) { 224 struct stat st; 225 unsigned nlen, error = 0, zero = 0; 226 int len, fd = -1; 227 ssize_t llen; 228 229 len = getline(&name, &size, stdin); 230 if (len<1) break; 231 if (name[len-1] == '\n') name[--len] = 0; 232 nlen = len+1; 233 if (lstat(name, &st) || (S_ISREG(st.st_mode) 234 && st.st_size && (fd = open(name, O_RDONLY))<0)) 235 { 236 perror_msg_raw(name); 237 continue; 238 } 239 240 if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode)) st.st_size = 0; 241 if (st.st_size >> 32) perror_msg("skipping >2G file '%s'", name); 242 else { 243 llen = sprintf(toybuf, 244 "070701%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X", 245 (int)st.st_ino, st.st_mode, st.st_uid, st.st_gid, (int)st.st_nlink, 246 (int)st.st_mtime, (int)st.st_size, major(st.st_dev), 247 minor(st.st_dev), major(st.st_rdev), minor(st.st_rdev), nlen, 0); 248 xwrite(afd, toybuf, llen); 249 xwrite(afd, name, nlen); 250 251 // NUL Pad header up to 4 multiple bytes. 252 llen = (llen + nlen) & 3; 253 if (llen) xwrite(afd, &zero, 4-llen); 254 255 // Write out body for symlink or regular file 256 llen = st.st_size; 257 if (S_ISLNK(st.st_mode)) { 258 if (readlink(name, toybuf, sizeof(toybuf)-1) == llen) 259 xwrite(afd, toybuf, llen); 260 else perror_msg("readlink '%s'", name); 261 } else while (llen) { 262 nlen = llen > sizeof(toybuf) ? sizeof(toybuf) : llen; 263 llen -= nlen; 264 // If read fails, write anyway (already wrote size in header) 265 if (nlen != readall(fd, toybuf, nlen)) 266 if (!error++) perror_msg("bad read from file '%s'", name); 267 xwrite(afd, toybuf, nlen); 268 } 269 llen = st.st_size & 3; 270 if (llen) xwrite(afd, &zero, 4-llen); 271 } 272 close(fd); 273 } 274 free(name); 275 276 memset(toybuf, 0, sizeof(toybuf)); 277 xwrite(afd, toybuf, 278 sprintf(toybuf, "070701%040X%056X%08XTRAILER!!!", 1, 0x0b, 0)+4); 279 } 280 if (TT.archive) xclose(afd); 281 282 if (TT.pass) toys.exitval |= xpclose(pid, pipe); 283 } 284
