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)(trailer)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 --trailer Add legacy trailer (prevents concatenation). 38 */ 39 40 #define FOR_cpio 41 #include "toys.h" 42 43 GLOBALS( 44 char *archive; 45 char *pass; 46 char *fmt; 47 ) 48 49 // Read strings, tail padded to 4 byte alignment. Argument "align" is amount 50 // by which start of string isn't aligned (usually 0, but header is 110 bytes 51 // which is 2 bytes off because the first field wasn't expanded from 6 to 8). 52 static char *strpad(int fd, unsigned len, unsigned align) 53 { 54 char *str; 55 56 align = (align + len) & 3; 57 if (align) len += (4-align); 58 xreadall(fd, str = xmalloc(len+1), len); 59 str[len]=0; // redundant, in case archive is bad 60 61 return str; 62 } 63 64 //convert hex to uint; mostly to allow using bits of non-terminated strings 65 static unsigned x8u(char *hex) 66 { 67 unsigned val, inpos = 8, outpos; 68 char pattern[6]; 69 70 while (*hex == '0') { 71 hex++; 72 if (!--inpos) return 0; 73 } 74 // Because scanf gratuitously treats %*X differently than printf does. 75 sprintf(pattern, "%%%dX%%n", inpos); 76 sscanf(hex, pattern, &val, &outpos); 77 if (inpos != outpos) error_exit("bad header"); 78 79 return val; 80 } 81 82 void cpio_main(void) 83 { 84 // Subtle bit: FLAG_o is 1 so we can just use it to select stdin/stdout. 85 int pipe, afd = toys.optflags & FLAG_o; 86 pid_t pid = 0; 87 88 // In passthrough mode, parent stays in original dir and generates archive 89 // to pipe, child does chdir to new dir and reads archive from stdin (pipe). 90 if (TT.pass) { 91 if (toys.stacktop) { 92 // xpopen() doesn't return from child due to vfork(), instead restarts 93 // with !toys.stacktop 94 pid = xpopen(0, &pipe, 0); 95 afd = pipe; 96 } else { 97 // child 98 toys.optflags |= FLAG_i; 99 xchdir(TT.pass); 100 } 101 } 102 103 if (TT.archive) { 104 int perm = (toys.optflags & FLAG_o) ? O_CREAT|O_WRONLY|O_TRUNC : O_RDONLY; 105 106 afd = xcreate(TT.archive, perm, 0644); 107 } 108 109 // read cpio archive 110 111 if (toys.optflags & (FLAG_i|FLAG_t)) for (;;) { 112 char *name, *tofree, *data; 113 unsigned size, mode, uid, gid, timestamp; 114 int test = toys.optflags & FLAG_t, err = 0; 115 116 // Read header and name. 117 if (!(size =readall(afd, toybuf, 110))) break; 118 if (size != 110 || memcmp(toybuf, "070701", 6)) error_exit("bad header"); 119 tofree = name = strpad(afd, x8u(toybuf+94), 110); 120 if (!strcmp("TRAILER!!!", name)) { 121 if (CFG_TOYBOX_FREE) free(tofree); 122 break; 123 } 124 125 // If you want to extract absolute paths, "cd /" and run cpio. 126 while (*name == '/') name++; 127 // TODO: remove .. entries 128 129 size = x8u(toybuf+54); 130 mode = x8u(toybuf+14); 131 uid = x8u(toybuf+22); 132 gid = x8u(toybuf+30); 133 timestamp = x8u(toybuf+46); // unsigned 32 bit, so year 2100 problem 134 135 if (toys.optflags & (FLAG_t|FLAG_v)) puts(name); 136 137 if (!test && strrchr(name, '/') && mkpathat(AT_FDCWD, name, 0, 2)) { 138 perror_msg("mkpath '%s'", name); 139 test++; 140 } 141 142 // Consume entire record even if it couldn't create file, so we're 143 // properly aligned with next file. 144 145 if (S_ISDIR(mode)) { 146 if (!test) err = mkdir(name, mode); 147 } else if (S_ISLNK(mode)) { 148 data = strpad(afd, size, 0); 149 if (!test) err = symlink(data, name); 150 free(data); 151 // Can't get a filehandle to a symlink, so do special chown 152 if (!err && !geteuid() && !(toys.optflags & FLAG_no_preserve_owner)) 153 err = lchown(name, uid, gid); 154 } else if (S_ISREG(mode)) { 155 int fd = test ? 0 : open(name, O_CREAT|O_WRONLY|O_TRUNC|O_NOFOLLOW, mode); 156 157 // If write fails, we still need to read/discard data to continue with 158 // archive. Since doing so overwrites errno, report error now 159 if (fd < 0) { 160 perror_msg("create %s", name); 161 test++; 162 } 163 164 data = toybuf; 165 while (size) { 166 if (size < sizeof(toybuf)) data = strpad(afd, size, 0); 167 else xreadall(afd, toybuf, sizeof(toybuf)); 168 if (!test) xwrite(fd, data, data == toybuf ? sizeof(toybuf) : size); 169 if (data != toybuf) { 170 free(data); 171 break; 172 } 173 size -= sizeof(toybuf); 174 } 175 176 if (!test) { 177 // set owner, restore dropped suid bit 178 if (!geteuid() && !(toys.optflags & FLAG_no_preserve_owner)) { 179 err = fchown(fd, uid, gid); 180 if (!err) err = fchmod(fd, mode); 181 } 182 close(fd); 183 } 184 } else if (!test) 185 err = mknod(name, mode, dev_makedev(x8u(toybuf+78), x8u(toybuf+86))); 186 187 // Set ownership and timestamp. 188 if (!test && !err) { 189 // Creading dir/dev doesn't give us a filehandle, we have to refer to it 190 // by name to chown/utime, but how do we know it's the same item? 191 // Check that we at least have the right type of entity open, and do 192 // NOT restore dropped suid bit in this case. 193 if (!S_ISREG(mode) && !S_ISLNK(mode) && !geteuid() 194 && !(toys.optflags & FLAG_no_preserve_owner)) 195 { 196 int fd = open(name, O_RDONLY|O_NOFOLLOW); 197 struct stat st; 198 199 if (fd != -1 && !fstat(fd, &st) && (st.st_mode&S_IFMT) == (mode&S_IFMT)) 200 err = fchown(fd, uid, gid); 201 else err = 1; 202 203 close(fd); 204 } 205 206 // set timestamp 207 if (!err) { 208 struct timespec times[2]; 209 210 memset(times, 0, sizeof(struct timespec)*2); 211 times[0].tv_sec = times[1].tv_sec = timestamp; 212 err = utimensat(AT_FDCWD, name, times, AT_SYMLINK_NOFOLLOW); 213 } 214 } 215 216 if (err) perror_msg_raw(name); 217 free(tofree); 218 219 // Output cpio archive 220 221 } else { 222 char *name = 0; 223 size_t size = 0; 224 225 for (;;) { 226 struct stat st; 227 unsigned nlen, error = 0, zero = 0; 228 int len, fd = -1; 229 ssize_t llen; 230 231 len = getline(&name, &size, stdin); 232 if (len<1) break; 233 if (name[len-1] == '\n') name[--len] = 0; 234 nlen = len+1; 235 if (lstat(name, &st) || (S_ISREG(st.st_mode) 236 && st.st_size && (fd = open(name, O_RDONLY))<0)) 237 { 238 perror_msg_raw(name); 239 continue; 240 } 241 242 if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode)) st.st_size = 0; 243 if (st.st_size >> 32) perror_msg("skipping >2G file '%s'", name); 244 else { 245 llen = sprintf(toybuf, 246 "070701%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X", 247 (int)st.st_ino, st.st_mode, st.st_uid, st.st_gid, (int)st.st_nlink, 248 (int)st.st_mtime, (int)st.st_size, dev_major(st.st_dev), 249 dev_minor(st.st_dev), dev_major(st.st_rdev), dev_minor(st.st_rdev), 250 nlen, 0); 251 xwrite(afd, toybuf, llen); 252 xwrite(afd, name, nlen); 253 254 // NUL Pad header up to 4 multiple bytes. 255 llen = (llen + nlen) & 3; 256 if (llen) xwrite(afd, &zero, 4-llen); 257 258 // Write out body for symlink or regular file 259 llen = st.st_size; 260 if (S_ISLNK(st.st_mode)) { 261 if (readlink(name, toybuf, sizeof(toybuf)-1) == llen) 262 xwrite(afd, toybuf, llen); 263 else perror_msg("readlink '%s'", name); 264 } else while (llen) { 265 nlen = llen > sizeof(toybuf) ? sizeof(toybuf) : llen; 266 llen -= nlen; 267 // If read fails, write anyway (already wrote size in header) 268 if (nlen != readall(fd, toybuf, nlen)) 269 if (!error++) perror_msg("bad read from file '%s'", name); 270 xwrite(afd, toybuf, nlen); 271 } 272 llen = st.st_size & 3; 273 if (llen) xwrite(afd, &zero, 4-llen); 274 } 275 close(fd); 276 } 277 free(name); 278 279 if (FLAG_trailer) { 280 memset(toybuf, 0, sizeof(toybuf)); 281 xwrite(afd, toybuf, 282 sprintf(toybuf, "070701%040X%056X%08XTRAILER!!!", 1, 0x0b, 0)+4); 283 } 284 } 285 if (TT.archive) xclose(afd); 286 287 if (TT.pass) toys.exitval |= xpclose(pid, pipe); 288 } 289
