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- /* cpio.c - a basic cpio
- *
- * Copyright 2013 Isaac Dunham <ibid.ag@gmail.com>
- * Copyright 2015 Frontier Silicon Ltd.
- *
- * see https://www.kernel.org/doc/Documentation/early-userspace/buffer-format.txt
- * and http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/cpio.html
- * and http://pubs.opengroup.org/onlinepubs/7908799/xcu/cpio.html
- *
- * Yes, that's SUSv2, newer versions removed it, but RPM and initramfs use
- * this archive format. We implement (only) the modern "-H newc" variant which
- * expanded headers to 110 bytes (first field 6 bytes, rest are 8).
- * In order: magic ino mode uid gid nlink mtime filesize devmajor devminor
- * rdevmajor rdevminor namesize check
- * This is the equivalent of mode -H newc in other implementations.
- *
- * todo: export/import linux file list text format ala gen_initramfs_list.sh
- USE_CPIO(NEWTOY(cpio, "(ignore-devno)(renumber-inodes)(quiet)(no-preserve-owner)md(make-directories)uH:p|i|t|F:v(verbose)o|[!pio][!pot][!pF]", TOYFLAG_BIN))
- config CPIO
- bool "cpio"
- default y
- help
- usage: cpio -{o|t|i|p DEST} [-v] [--verbose] [-F FILE] [--no-preserve-owner]
- [ignored: -m -H newc]
- Copy files into and out of a "newc" format cpio archive.
- -F FILE Use archive FILE instead of stdin/stdout
- -p DEST Copy-pass mode, copy stdin file list to directory DEST
- -i Extract from archive into file system (stdin=archive)
- -o Create archive (stdin=list of files, stdout=archive)
- -t Test files (list only, stdin=archive, stdout=list of files)
- -d Create directories if needed
- -u unlink existing files when extracting
- -v Verbose
- --no-preserve-owner (don't set ownership during extract)
- */
- #define FOR_cpio
- #include "toys.h"
- GLOBALS(
- char *F, *H;
- )
- // Read strings, tail padded to 4 byte alignment. Argument "align" is amount
- // by which start of string isn't aligned (usually 0, but header is 110 bytes
- // which is 2 bytes off because the first field wasn't expanded from 6 to 8).
- static char *strpad(int fd, unsigned len, unsigned align)
- {
- char *str;
- align = (align + len) & 3;
- if (align) len += (4-align);
- xreadall(fd, str = xmalloc(len+1), len);
- str[len]=0; // redundant, in case archive is bad
- return str;
- }
- //convert hex to uint; mostly to allow using bits of non-terminated strings
- static unsigned x8u(char *hex)
- {
- unsigned val, inpos = 8, outpos;
- char pattern[6];
- while (*hex == '0') {
- hex++;
- if (!--inpos) return 0;
- }
- // Because scanf gratuitously treats %*X differently than printf does.
- sprintf(pattern, "%%%dX%%n", inpos);
- sscanf(hex, pattern, &val, &outpos);
- if (inpos != outpos) error_exit("bad hex");
- return val;
- }
- void cpio_main(void)
- {
- // Subtle bit: FLAG_o is 1 so we can just use it to select stdin/stdout.
- int pipe, afd = FLAG(o), empty = 1;
- pid_t pid = 0;
- // In passthrough mode, parent stays in original dir and generates archive
- // to pipe, child does chdir to new dir and reads archive from stdin (pipe).
- if (FLAG(p)) {
- if (FLAG(d)) {
- if (!*toys.optargs) error_exit("need directory for -p");
- if (mkdir(*toys.optargs, 0700) == -1 && errno != EEXIST)
- perror_exit("mkdir %s", *toys.optargs);
- }
- if (toys.stacktop) {
- // xpopen() doesn't return from child due to vfork(), instead restarts
- // with !toys.stacktop
- pid = xpopen(0, &pipe, 0);
- afd = pipe;
- } else {
- // child
- toys.optflags |= FLAG_i;
- xchdir(*toys.optargs);
- }
- }
- if (TT.F) {
- int perm = FLAG(o) ? O_CREAT|O_WRONLY|O_TRUNC : O_RDONLY;
- afd = xcreate(TT.F, perm, 0644);
- }
- // read cpio archive
- if (FLAG(i) || FLAG(t)) for (;; empty = 0) {
- char *name, *tofree, *data;
- unsigned mode, uid, gid, timestamp;
- int test = FLAG(t), err = 0, size = 0, len;
- // read header, skipping arbitrary leading NUL bytes (concatenated archives)
- for (;;) {
- if (1>(len = readall(afd, toybuf+size, 110-size))) break;
- if (size || *toybuf) {
- size += len;
- break;
- }
- for (size = 0; size<len; size++) if (toybuf[size]) break;
- memmove(toybuf, toybuf+size, len-size);
- size = len-size;
- }
- if (!size) {
- if (empty) error_exit("empty archive");
- else break;
- }
- if (size != 110 || memcmp(toybuf, "070701", 6)) error_exit("bad header");
- tofree = name = strpad(afd, x8u(toybuf+94), 110);
- if (!strcmp("TRAILER!!!", name)) {
- free(tofree);
- continue;
- }
- // If you want to extract absolute paths, "cd /" and run cpio.
- while (*name == '/') name++;
- // TODO: remove .. entries
- size = x8u(toybuf+54);
- mode = x8u(toybuf+14);
- uid = x8u(toybuf+22);
- gid = x8u(toybuf+30);
- timestamp = x8u(toybuf+46); // unsigned 32 bit, so year 2100 problem
- // (This output is unaffected by --quiet.)
- if (FLAG(t) || FLAG(v)) puts(name);
- if (FLAG(u) && !test) if (unlink(name) && errno == EISDIR) rmdir(name);
- if (!test && FLAG(d) && strrchr(name, '/') && mkpath(name)) {
- perror_msg("mkpath '%s'", name);
- test++;
- }
- // Consume entire record even if it couldn't create file, so we're
- // properly aligned with next file.
- if (S_ISDIR(mode)) {
- if (!test) err = mkdir(name, mode) && !FLAG(u);
- } else if (S_ISLNK(mode)) {
- data = strpad(afd, size, 0);
- if (!test) {
- err = symlink(data, name);
- // Can't get a filehandle to a symlink, so do special chown
- if (!err && !geteuid() && !FLAG(no_preserve_owner))
- err = lchown(name, uid, gid);
- }
- free(data);
- } else if (S_ISREG(mode)) {
- int fd = test ? 0 : open(name, O_CREAT|O_WRONLY|O_EXCL|O_NOFOLLOW, mode);
- // If write fails, we still need to read/discard data to continue with
- // archive. Since doing so overwrites errno, report error now
- if (fd < 0) {
- perror_msg("create %s", name);
- test++;
- }
- data = toybuf;
- while (size) {
- if (size < sizeof(toybuf)) data = strpad(afd, size, 0);
- else xreadall(afd, toybuf, sizeof(toybuf));
- if (!test) xwrite(fd, data, data == toybuf ? sizeof(toybuf) : size);
- if (data != toybuf) {
- free(data);
- break;
- }
- size -= sizeof(toybuf);
- }
- if (!test) {
- // set owner, restore dropped suid bit
- if (!geteuid() && !FLAG(no_preserve_owner)) {
- err = fchown(fd, uid, gid);
- if (!err) err = fchmod(fd, mode);
- }
- close(fd);
- }
- } else if (!test)
- err = mknod(name, mode, dev_makedev(x8u(toybuf+78), x8u(toybuf+86)));
- // Set ownership and timestamp.
- if (!test && !err) {
- // Creading dir/dev doesn't give us a filehandle, we have to refer to it
- // by name to chown/utime, but how do we know it's the same item?
- // Check that we at least have the right type of entity open, and do
- // NOT restore dropped suid bit in this case.
- if (!S_ISREG(mode) && !S_ISLNK(mode) && !geteuid()
- && !FLAG(no_preserve_owner))
- {
- int fd = open(name, O_RDONLY|O_NOFOLLOW);
- struct stat st;
- if (fd != -1 && !fstat(fd, &st) && (st.st_mode&S_IFMT) == (mode&S_IFMT))
- err = fchown(fd, uid, gid);
- else err = 1;
- close(fd);
- }
- // set timestamp
- if (!err) {
- struct timespec times[2];
- memset(times, 0, sizeof(struct timespec)*2);
- times[0].tv_sec = times[1].tv_sec = timestamp;
- err = utimensat(AT_FDCWD, name, times, AT_SYMLINK_NOFOLLOW);
- }
- }
- if (err) perror_msg_raw(name);
- free(tofree);
- // Output cpio archive
- } else {
- char *name = 0;
- size_t size = 0;
- unsigned inode = 0;
- for (;;) {
- struct stat st;
- unsigned nlen, error = 0, zero = 0;
- int len, fd = -1;
- char *link = 0;
- ssize_t llen;
- len = getline(&name, &size, stdin);
- if (len<1) break;
- if (name[len-1] == '\n') name[--len] = 0;
- nlen = len+1;
- if (lstat(name, &st) || (S_ISREG(st.st_mode)
- && st.st_size && (fd = open(name, O_RDONLY))<0)
- || (S_ISLNK(st.st_mode) && !(link = xreadlink(name))))
- {
- perror_msg_raw(name);
- continue;
- }
- // encrypted filesystems can stat the wrong link size
- if (link) st.st_size = strlen(link);
- if (FLAG(no_preserve_owner)) st.st_uid = st.st_gid = 0;
- if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode)) st.st_size = 0;
- if (st.st_size >> 32) perror_msg("skipping >2G file '%s'", name);
- else {
- if (FLAG(renumber_inodes)) st.st_ino = ++inode;
- if (FLAG(ignore_devno)) st.st_rdev = 0;
- llen = sprintf(toybuf,
- "070701%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X%08X",
- (int)st.st_ino, st.st_mode, st.st_uid, st.st_gid, (int)st.st_nlink,
- (int)st.st_mtime, (int)st.st_size, dev_major(st.st_dev),
- dev_minor(st.st_dev), dev_major(st.st_rdev), dev_minor(st.st_rdev),
- nlen, 0);
- xwrite(afd, toybuf, llen);
- xwrite(afd, name, nlen);
- // NUL Pad header up to 4 multiple bytes.
- llen = (llen + nlen) & 3;
- if (llen) xwrite(afd, &zero, 4-llen);
- // Write out body for symlink or regular file
- if (link) xwrite(afd, link, st.st_size);
- else for (llen = st.st_size; llen; llen -= nlen) {
- nlen = llen > sizeof(toybuf) ? sizeof(toybuf) : llen;
- // If read fails, write anyway (already wrote size in header)
- if (nlen != readall(fd, toybuf, nlen))
- if (!error++) perror_msg("bad read from file '%s'", name);
- xwrite(afd, toybuf, nlen);
- }
- llen = st.st_size & 3;
- if (llen) xwrite(afd, &zero, 4-llen);
- }
- free(link);
- xclose(fd);
- }
- if (CFG_TOYBOX_FREE) free(name);
- // nlink=1, namesize=11, with padding
- dprintf(afd, "070701%040X%056X%08XTRAILER!!!%c%c%c%c", 1, 11, 0, 0, 0, 0,0);
- }
- if (TT.F) xclose(afd);
- if (FLAG(p) && pid) toys.exitval |= xpclose(pid, pipe);
- }
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