blob: 5524dba29fa14a2db6eff00e059b5ac7b8d97401 [file] [log] [blame]
/* cpio.c - a basic cpio
*
* Written 2013 AD by Isaac Dunham; this code is placed under the
* same license as toybox or as CC0, at your option.
*
* Portions Copyright 2015 by Frontier Silicon Ltd.
*
* 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, the newer standards removed it around the time RPM
* and initramfs started heavily using this archive format.
*
* Modern cpio expanded header 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 equiavlent of mode -H newc when using GNU CPIO.
USE_CPIO(NEWTOY(cpio, "(no-preserve-owner)mduH: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: -mdu -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)
-v verbose (list files during create/extract)
--no-preserve-owner (don't set ownership during extract)
*/
#define FOR_cpio
#include "toys.h"
GLOBALS(
char *archive;
char *pass;
char *fmt;
)
// 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 header");
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 = toys.optflags & FLAG_o;
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 (TT.pass) {
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(TT.pass);
}
}
if (TT.archive) {
int perm = (toys.optflags & FLAG_o) ? O_CREAT|O_WRONLY|O_TRUNC : O_RDONLY;
afd = xcreate(TT.archive, perm, 0644);
}
// read cpio archive
if (toys.optflags & (FLAG_i|FLAG_t)) for (;;) {
char *name, *tofree, *data;
unsigned size, mode, uid, gid, timestamp;
int test = toys.optflags & FLAG_t, err = 0;
// Read header and name.
xreadall(afd, toybuf, 110);
if (memcmp(toybuf, "070701", 6)) error_exit("bad cpio magic");
tofree = name = strpad(afd, x8u(toybuf+94), 110);
if (!strcmp("TRAILER!!!", name)) {
if (CFG_TOYBOX_FREE) free(tofree);
break;
}
// 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
if (toys.optflags & (FLAG_t|FLAG_v)) puts(name);
if (!test && strrchr(name, '/') && mkpathat(AT_FDCWD, name, 0, 2)) {
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);
} else if (S_ISLNK(mode)) {
data = strpad(afd, size, 0);
if (!test) err = symlink(data, name);
free(data);
// Can't get a filehandle to a symlink, so do special chown
if (!err && !geteuid() && !(toys.optflags & FLAG_no_preserve_owner))
err = lchown(name, uid, gid);
} else if (S_ISREG(mode)) {
int fd = test ? 0 : open(name, O_CREAT|O_WRONLY|O_TRUNC|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() && !(toys.optflags & 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()
&& !(toys.optflags & 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;
for (;;) {
struct stat st;
unsigned nlen, error = 0, zero = 0;
int len, fd = -1;
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))
{
perror_msg_raw(name);
continue;
}
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 {
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
llen = st.st_size;
if (S_ISLNK(st.st_mode)) {
if (readlink(name, toybuf, sizeof(toybuf)-1) == llen)
xwrite(afd, toybuf, llen);
else perror_msg("readlink '%s'", name);
} else while (llen) {
nlen = llen > sizeof(toybuf) ? sizeof(toybuf) : llen;
llen -= nlen;
// 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);
}
close(fd);
}
free(name);
memset(toybuf, 0, sizeof(toybuf));
xwrite(afd, toybuf,
sprintf(toybuf, "070701%040X%056X%08XTRAILER!!!", 1, 0x0b, 0)+4);
}
if (TT.archive) xclose(afd);
if (TT.pass) toys.exitval |= xpclose(pid, pipe);
}