path: root/archival/libarchive/data_extract_all.c (plain)
blob: 5d8e57a78e19e90078f6548d2fc4ff1c6e17f733

1	/* vi: set sw=4 ts=4: */
2	/*
3	* Licensed under GPLv2 or later, see file LICENSE in this source tree.
4	*/
5
6	#include "libbb.h"
7	#include "bb_archive.h"
8
9	void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
10	{
11	file_header_t *file_header = archive_handle->file_header;
12	int dst_fd;
13	int res;
14	char *hard_link;
15	#if ENABLE_FEATURE_TAR_LONG_OPTIONS
16	char *dst_name;
17	#else
18	# define dst_name (file_header->name)
19	#endif
20
21	#if ENABLE_FEATURE_TAR_SELINUX
22	char *sctx = archive_handle->tar__sctx[PAX_NEXT_FILE];
23	#ifdef __BIONIC__
24	matchpathcon_init(NULL);
25	#endif
26	if (!sctx)
27	sctx = archive_handle->tar__sctx[PAX_GLOBAL];
28	if (sctx) { /* setfscreatecon is 4 syscalls, avoid if possible */
29	setfscreatecon(sctx);
30	free(archive_handle->tar__sctx[PAX_NEXT_FILE]);
31	archive_handle->tar__sctx[PAX_NEXT_FILE] = NULL;
32	}
33	#endif
34
35	/* Hard links are encoded as regular files of size 0
36	* with a nonempty link field */
37	hard_link = NULL;
38	if (S_ISREG(file_header->mode) && file_header->size == 0)
39	hard_link = file_header->link_target;
40
41	#if ENABLE_FEATURE_TAR_LONG_OPTIONS
42	dst_name = file_header->name;
43	if (archive_handle->tar__strip_components) {
44	unsigned n = archive_handle->tar__strip_components;
45	do {
46	dst_name = strchr(dst_name, '/');
47	if (!dst_name || dst_name[1] == '\0') {
48	data_skip(archive_handle);
49	goto ret;
50	}
51	dst_name++;
52	/*
53	* Link target is shortened only for hardlinks:
54	* softlinks restored unchanged.
55	*/
56	if (hard_link) {
57	// GNU tar 1.26 does not check that we reached end of link name:
58	// if "dir/hardlink" is hardlinked to "file",
59	// tar xvf a.tar --strip-components=1 says:
60	// tar: hardlink: Cannot hard link to '': No such file or directory
61	// and continues processing. We silently skip such entries.
62	hard_link = strchr(hard_link, '/');
63	if (!hard_link || hard_link[1] == '\0') {
64	data_skip(archive_handle);
65	goto ret;
66	}
67	hard_link++;
68	}
69	} while (--n != 0);
70	}
71	#endif
72
73	if (archive_handle->ah_flags & ARCHIVE_CREATE_LEADING_DIRS) {
74	char *slash = strrchr(dst_name, '/');
75	if (slash) {
76	*slash = '\0';
77	bb_make_directory(dst_name, -1, FILEUTILS_RECUR);
78	*slash = '/';
79	}
80	}
81
82	if (archive_handle->ah_flags & ARCHIVE_UNLINK_OLD) {
83	/* Remove the entry if it exists */
84	if (!S_ISDIR(file_header->mode)) {
85	if (hard_link) {
86	/* Ugly special case:
87	* tar cf t.tar hardlink1 hardlink2 hardlink1
88	* results in this tarball structure:
89	* hardlink1
90	* hardlink2 -> hardlink1
91	* hardlink1 -> hardlink1 <== !!!
92	*/
93	if (strcmp(hard_link, dst_name) == 0)
94	goto ret;
95	}
96	/* Proceed with deleting */
97	if (unlink(dst_name) == -1
98	&& errno != ENOENT
99	) {
100	bb_perror_msg_and_die("can't remove old file %s",
101	dst_name);
102	}
103	}
104	}
105	else if (archive_handle->ah_flags & ARCHIVE_EXTRACT_NEWER) {
106	/* Remove the existing entry if its older than the extracted entry */
107	struct stat existing_sb;
108	if (lstat(dst_name, &existing_sb) == -1) {
109	if (errno != ENOENT) {
110	bb_perror_msg_and_die("can't stat old file");
111	}
112	}
113	else if ((time_t) existing_sb.st_mtime >= (time_t) file_header->mtime) {
114	if (!(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
115	&& !S_ISDIR(file_header->mode)
116	) {
117	bb_error_msg("%s not created: newer or "
118	"same age file exists", dst_name);
119	}
120	data_skip(archive_handle);
121	goto ret;
122	}
123	else if ((unlink(dst_name) == -1) && (errno != EISDIR)) {
124	bb_perror_msg_and_die("can't remove old file %s",
125	dst_name);
126	}
127	}
128
129	/* Handle hard links separately */
130	if (hard_link) {
131	res = link(hard_link, dst_name);
132	if (res != 0 && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)) {
133	bb_perror_msg("can't create %slink "
134	"from %s to %s", "hard",
135	dst_name,
136	hard_link);
137	}
138	/* Hardlinks have no separate mode/ownership, skip chown/chmod */
139	goto ret;
140	}
141
142	/* Create the filesystem entry */
143	switch (file_header->mode & S_IFMT) {
144	case S_IFREG: {
145	/* Regular file */
146	char *dst_nameN;
147	int flags = O_WRONLY | O_CREAT | O_EXCL;
148	if (archive_handle->ah_flags & ARCHIVE_O_TRUNC)
149	flags = O_WRONLY | O_CREAT | O_TRUNC;
150	dst_nameN = dst_name;
151	#ifdef ARCHIVE_REPLACE_VIA_RENAME
152	if (archive_handle->ah_flags & ARCHIVE_REPLACE_VIA_RENAME)
153	/* rpm-style temp file name */
154	dst_nameN = xasprintf("%s;%x", dst_name, (int)getpid());
155	#endif
156	dst_fd = xopen3(dst_nameN,
157	flags,
158	file_header->mode
159	);
160	bb_copyfd_exact_size(archive_handle->src_fd, dst_fd, file_header->size);
161	close(dst_fd);
162	#ifdef ARCHIVE_REPLACE_VIA_RENAME
163	if (archive_handle->ah_flags & ARCHIVE_REPLACE_VIA_RENAME) {
164	xrename(dst_nameN, dst_name);
165	free(dst_nameN);
166	}
167	#endif
168	break;
169	}
170	case S_IFDIR:
171	res = mkdir(dst_name, file_header->mode);
172	if ((res == -1)
173	&& (errno != EISDIR) /* btw, Linux doesn't return this */
174	&& (errno != EEXIST)
175	&& !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
176	) {
177	bb_perror_msg("can't make dir %s", dst_name);
178	}
179	break;
180	case S_IFLNK:
181	/* Symlink */
182	//TODO: what if file_header->link_target == NULL (say, corrupted tarball?)
183	res = symlink(file_header->link_target, dst_name);
184	if (res != 0
185	&& !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
186	) {
187	bb_perror_msg("can't create %slink "
188	"from %s to %s", "sym",
189	dst_name,
190	file_header->link_target);
191	}
192	break;
193	case S_IFSOCK:
194	case S_IFBLK:
195	case S_IFCHR:
196	case S_IFIFO:
197	res = mknod(dst_name, file_header->mode, file_header->device);
198	if ((res == -1)
199	&& !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
200	) {
201	bb_perror_msg("can't create node %s", dst_name);
202	}
203	break;
204	default:
205	bb_error_msg_and_die("unrecognized file type");
206	}
207
208	if (!S_ISLNK(file_header->mode)) {
209	if (!(archive_handle->ah_flags & ARCHIVE_DONT_RESTORE_OWNER)) {
210	uid_t uid = file_header->uid;
211	gid_t gid = file_header->gid;
212	#if ENABLE_FEATURE_TAR_UNAME_GNAME
213	if (!(archive_handle->ah_flags & ARCHIVE_NUMERIC_OWNER)) {
214	if (file_header->tar__uname) {
215	//TODO: cache last name/id pair?
216	struct passwd *pwd = getpwnam(file_header->tar__uname);
217	if (pwd) uid = pwd->pw_uid;
218	}
219	if (file_header->tar__gname) {
220	struct group *grp = getgrnam(file_header->tar__gname);
221	if (grp) gid = grp->gr_gid;
222	}
223	}
224	#endif
225	/* GNU tar 1.15.1 uses chown, not lchown */
226	chown(dst_name, uid, gid);
227	}
228	/* uclibc has no lchmod, glibc is even stranger -
229	* it has lchmod which seems to do nothing!
230	* so we use chmod... */
231	if (!(archive_handle->ah_flags & ARCHIVE_DONT_RESTORE_PERM)) {
232	chmod(dst_name, file_header->mode);
233	}
234	if (archive_handle->ah_flags & ARCHIVE_RESTORE_DATE) {
235	struct timeval t[2];
236
237	t[1].tv_sec = t[0].tv_sec = file_header->mtime;
238	t[1].tv_usec = t[0].tv_usec = 0;
239	utimes(dst_name, t);
240	}
241	}
242
243	ret: ;
244	#if ENABLE_FEATURE_TAR_SELINUX
245	if (sctx) {
246	/* reset the context after creating an entry */
247	setfscreatecon(NULL);
248	}
249	#endif
250	}
251