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
GLOBALS(char * archive;char * pass;char * fmt;)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
x8u(char * hex)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
cpio_main(void)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