1 /* cpio.c - a basic cpio
2 *
3 * Copyright 2013 Isaac Dunham <ibid.ag@gmail.com>
4 * Copyright 2015 Frontier Silicon Ltd.
5 *
6 * see https://www.kernel.org/doc/Documentation/early-userspace/buffer-format.txt
7 * and http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/cpio.html
8 * and http://pubs.opengroup.org/onlinepubs/7908799/xcu/cpio.html
9 *
10 * Yes, that's SUSv2, newer versions removed it, but RPM and initramfs use
11 * this archive format. We implement (only) the modern "-H newc" variant which
12 * expanded headers 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 * This is the equivalent of mode -H newc in other implementations.
16 *
17 * todo: export/import linux file list text format ala gen_initramfs_list.sh
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
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 *F, *p, *H;
45 )
46
47 // Read strings, tail padded to 4 byte alignment. Argument "align" is amount
48 // by which start of string isn't aligned (usually 0, but header is 110 bytes
49 // which is 2 bytes off because the first field wasn't expanded from 6 to 8).
strpad(int fd,unsigned len,unsigned align)50 static char *strpad(int fd, unsigned len, unsigned align)
51 {
52 char *str;
53
54 align = (align + len) & 3;
55 if (align) len += (4-align);
56 xreadall(fd, str = xmalloc(len+1), len);
57 str[len]=0; // redundant, in case archive is bad
58
59 return str;
60 }
61
62 //convert hex to uint; mostly to allow using bits of non-terminated strings
x8u(char * hex)63 static unsigned x8u(char *hex)
64 {
65 unsigned val, inpos = 8, outpos;
66 char pattern[6];
67
68 while (*hex == '0') {
69 hex++;
70 if (!--inpos) return 0;
71 }
72 // Because scanf gratuitously treats %*X differently than printf does.
73 sprintf(pattern, "%%%dX%%n", inpos);
74 sscanf(hex, pattern, &val, &outpos);
75 if (inpos != outpos) error_exit("bad header");
76
77 return val;
78 }
79
cpio_main(void)80 void cpio_main(void)
81 {
82 // Subtle bit: FLAG_o is 1 so we can just use it to select stdin/stdout.
83 int pipe, afd = toys.optflags & FLAG_o;
84 pid_t pid = 0;
85
86 // In passthrough mode, parent stays in original dir and generates archive
87 // to pipe, child does chdir to new dir and reads archive from stdin (pipe).
88 if (TT.p) {
89 if (toys.stacktop) {
90 // xpopen() doesn't return from child due to vfork(), instead restarts
91 // with !toys.stacktop
92 pid = xpopen(0, &pipe, 0);
93 afd = pipe;
94 } else {
95 // child
96 toys.optflags |= FLAG_i;
97 xchdir(TT.p);
98 }
99 }
100
101 if (TT.F) {
102 int perm = (toys.optflags & FLAG_o) ? O_CREAT|O_WRONLY|O_TRUNC : O_RDONLY;
103
104 afd = xcreate(TT.F, perm, 0644);
105 }
106
107 // read cpio archive
108
109 if (toys.optflags & (FLAG_i|FLAG_t)) for (;;) {
110 char *name, *tofree, *data;
111 unsigned size, mode, uid, gid, timestamp;
112 int test = toys.optflags & FLAG_t, err = 0;
113
114 // Read header and name.
115 if (!(size =readall(afd, toybuf, 110))) break;
116 if (size != 110 || memcmp(toybuf, "070701", 6)) error_exit("bad header");
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, '/') && mkpath(name)) {
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, dev_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, dev_major(st.st_dev),
247 dev_minor(st.st_dev), dev_major(st.st_rdev), dev_minor(st.st_rdev),
248 nlen, 0);
249 xwrite(afd, toybuf, llen);
250 xwrite(afd, name, nlen);
251
252 // NUL Pad header up to 4 multiple bytes.
253 llen = (llen + nlen) & 3;
254 if (llen) xwrite(afd, &zero, 4-llen);
255
256 // Write out body for symlink or regular file
257 llen = st.st_size;
258 if (S_ISLNK(st.st_mode)) {
259 if (readlink(name, toybuf, sizeof(toybuf)-1) == llen)
260 xwrite(afd, toybuf, llen);
261 else perror_msg("readlink '%s'", name);
262 } else while (llen) {
263 nlen = llen > sizeof(toybuf) ? sizeof(toybuf) : llen;
264 llen -= nlen;
265 // If read fails, write anyway (already wrote size in header)
266 if (nlen != readall(fd, toybuf, nlen))
267 if (!error++) perror_msg("bad read from file '%s'", name);
268 xwrite(afd, toybuf, nlen);
269 }
270 llen = st.st_size & 3;
271 if (llen) xwrite(afd, &zero, 4-llen);
272 }
273 close(fd);
274 }
275 free(name);
276
277 if (FLAG_trailer) {
278 memset(toybuf, 0, sizeof(toybuf));
279 xwrite(afd, toybuf,
280 sprintf(toybuf, "070701%040X%056X%08XTRAILER!!!", 1, 0x0b, 0)+4);
281 }
282 }
283 if (TT.F) xclose(afd);
284
285 if (TT.p) toys.exitval |= xpclose(pid, pipe);
286 }
287