archival/libunarchive/get_header_tar.c

/* vi: set sw=4 ts=4: */
/* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 *  FIXME:
 *    In privileged mode if uname and gname map to a uid and gid then use the
 *    mapped value instead of the uid/gid values in tar header
 *
 *  References:
 *    GNU tar and star man pages,
 *    Opengroup's ustar interchange format,
 *	http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
 */

#include "libbb.h"
#include "unarchive.h"

/* NB: _DESTROYS_ str[len] character! */
static unsigned long long getOctal(char *str, int len)
{
	unsigned long long v;
	/* NB: leading spaces are allowed. Using strtoull to handle that.
	 * The downside is that we accept e.g. "-123" too :)
	 */
	str[len] = '\0';
	v = strtoull(str, &str, 8);
	if (*str && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY || *str != ' '))
		bb_error_msg_and_die("corrupted octal value in tar header");
	return v;
}
#define GET_OCTAL(a) getOctal((a), sizeof(a))

void BUG_tar_header_size(void);
char FAST_FUNC get_header_tar(archive_handle_t *archive_handle)
{
	file_header_t *file_header = archive_handle->file_header;
	struct {
		/* ustar header, Posix 1003.1 */
		char name[100];     /*   0-99 */
		char mode[8];       /* 100-107 */
		char uid[8];        /* 108-115 */
		char gid[8];        /* 116-123 */
		char size[12];      /* 124-135 */
		char mtime[12];     /* 136-147 */
		char chksum[8];     /* 148-155 */
		char typeflag;      /* 156-156 */
		char linkname[100]; /* 157-256 */
		/* POSIX:   "ustar" NUL "00" */
		/* GNU tar: "ustar  " NUL */
		/* Normally it's defined as magic[6] followed by
		 * version[2], but we put them together to simplify code
		 */
		char magic[8];      /* 257-264 */
		char uname[32];     /* 265-296 */
		char gname[32];     /* 297-328 */
		char devmajor[8];   /* 329-336 */
		char devminor[8];   /* 337-344 */
		char prefix[155];   /* 345-499 */
		char padding[12];   /* 500-512 */
	} tar;
	char *cp;
	int i, sum_u, sum;
#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
	int sum_s;
#endif
	int parse_names;

	/* Our "private data" */
#define p_end (*(smallint *)(&archive_handle->ah_priv[0]))
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
#define p_longname (*(char* *)(&archive_handle->ah_priv[1]))
#define p_linkname (*(char* *)(&archive_handle->ah_priv[2]))
#else
#define p_longname 0
#define p_linkname 0
#endif
//	if (!archive_handle->ah_priv_inited) {
//		archive_handle->ah_priv_inited = 1;
//		p_end = 0;
//		USE_FEATURE_TAR_GNU_EXTENSIONS(p_longname = NULL;)
//		USE_FEATURE_TAR_GNU_EXTENSIONS(p_linkname = NULL;)
//	}

	if (sizeof(tar) != 512)
		BUG_tar_header_size();

#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
 again:
#endif
	/* Align header */
	data_align(archive_handle, 512);

 again_after_align:

#if ENABLE_DESKTOP || ENABLE_FEATURE_TAR_AUTODETECT
	/* to prevent misdetection of bz2 sig */
	*(uint32_t*)(&tar) = 0;
	i = full_read(archive_handle->src_fd, &tar, 512);
	/* If GNU tar sees EOF in above read, it says:
	 * "tar: A lone zero block at N", where N = kilobyte
	 * where EOF was met (not EOF block, actual EOF!),
	 * and exits with EXIT_SUCCESS.
	 * We will mimic exit(EXIT_SUCCESS), although we will not mimic
	 * the message and we don't check whether we indeed
	 * saw zero block directly before this. */
	if (i == 0) {
		xfunc_error_retval = 0;
 short_read:
		bb_error_msg_and_die("short read");
	}
	if (i != 512) {
		USE_FEATURE_TAR_AUTODETECT(goto autodetect;)
		goto short_read;
	}

#else
	i = 512;
	xread(archive_handle->src_fd, &tar, i);
#endif
	archive_handle->offset += i;

	/* If there is no filename its an empty header */
	if (tar.name[0] == 0 && tar.prefix[0] == 0) {
		if (p_end) {
			/* Second consecutive empty header - end of archive.
			 * Read until the end to empty the pipe from gz or bz2
			 */
			while (full_read(archive_handle->src_fd, &tar, 512) == 512)
				continue;
			return EXIT_FAILURE;
		}
		p_end = 1;
		return EXIT_SUCCESS;
	}
	p_end = 0;

	/* Check header has valid magic, "ustar" is for the proper tar,
	 * five NULs are for the old tar format  */
	if (strncmp(tar.magic, "ustar", 5) != 0
	 && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
	     || memcmp(tar.magic, "\0\0\0\0", 5) != 0)
	) {
#if ENABLE_FEATURE_TAR_AUTODETECT
		char FAST_FUNC (*get_header_ptr)(archive_handle_t *);

 autodetect:
		/* tar gz/bz autodetect: check for gz/bz2 magic.
		 * If we see the magic, and it is the very first block,
		 * we can switch to get_header_tar_gz/bz2/lzma().
		 * Needs seekable fd. I wish recv(MSG_PEEK) works
		 * on any fd... */
#if ENABLE_FEATURE_SEAMLESS_GZ
		if (tar.name[0] == 0x1f && tar.name[1] == (char)0x8b) { /* gzip */
			get_header_ptr = get_header_tar_gz;
		} else
#endif
#if ENABLE_FEATURE_SEAMLESS_BZ2
		if (tar.name[0] == 'B' && tar.name[1] == 'Z'
		 && tar.name[2] == 'h' && isdigit(tar.name[3])
		) { /* bzip2 */
			get_header_ptr = get_header_tar_bz2;
		} else
#endif
			goto err;
		/* Two different causes for lseek() != 0:
		 * unseekable fd (would like to support that too, but...),
		 * or not first block (false positive, it's not .gz/.bz2!) */
		if (lseek(archive_handle->src_fd, -i, SEEK_CUR) != 0)
			goto err;
		while (get_header_ptr(archive_handle) == EXIT_SUCCESS)
			continue;
		return EXIT_FAILURE;
 err:
#endif /* FEATURE_TAR_AUTODETECT */
		bb_error_msg_and_die("invalid tar magic");
	}

	/* Do checksum on headers.
	 * POSIX says that checksum is done on unsigned bytes, but
	 * Sun and HP-UX gets it wrong... more details in
	 * GNU tar source. */
#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
	sum_s = ' ' * sizeof(tar.chksum);
#endif
	sum_u = ' ' * sizeof(tar.chksum);
	for (i = 0; i < 148; i++) {
		sum_u += ((unsigned char*)&tar)[i];
#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
		sum_s += ((signed char*)&tar)[i];
#endif
	}
	for (i = 156; i < 512; i++) {
		sum_u += ((unsigned char*)&tar)[i];
#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
		sum_s += ((signed char*)&tar)[i];
#endif
	}
#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
	sum = strtoul(tar.chksum, &cp, 8);
	if ((*cp && *cp != ' ')
	 || (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum))
	) {
		bb_error_msg_and_die("invalid tar header checksum");
	}
#else
	/* This field does not need special treatment (getOctal) */
	sum = xstrtoul(tar.chksum, 8);
	if (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) {
		bb_error_msg_and_die("invalid tar header checksum");
	}
#endif

	/* 0 is reserved for high perf file, treat as normal file */
	if (!tar.typeflag) tar.typeflag = '0';
	parse_names = (tar.typeflag >= '0' && tar.typeflag <= '7');

	/* getOctal trashes subsequent field, therefore we call it
	 * on fields in reverse order */
	if (tar.devmajor[0]) {
		char t = tar.prefix[0];
		/* we trash prefix[0] here, but we DO need it later! */
		unsigned minor = GET_OCTAL(tar.devminor);
		unsigned major = GET_OCTAL(tar.devmajor);
		file_header->device = makedev(major, minor);
		tar.prefix[0] = t;
	}
	file_header->link_target = NULL;
	if (!p_linkname && parse_names && tar.linkname[0]) {
		file_header->link_target = xstrndup(tar.linkname, sizeof(tar.linkname));
		/* FIXME: what if we have non-link object with link_target? */
		/* Will link_target be free()ed? */
	}
#if ENABLE_FEATURE_TAR_UNAME_GNAME
	file_header->uname = tar.uname[0] ? xstrndup(tar.uname, sizeof(tar.uname)) : NULL;
	file_header->gname = tar.gname[0] ? xstrndup(tar.gname, sizeof(tar.gname)) : NULL;
#endif
	file_header->mtime = GET_OCTAL(tar.mtime);
	file_header->size = GET_OCTAL(tar.size);
	file_header->gid = GET_OCTAL(tar.gid);
	file_header->uid = GET_OCTAL(tar.uid);
	/* Set bits 0-11 of the files mode */
	file_header->mode = 07777 & GET_OCTAL(tar.mode);

	file_header->name = NULL;
	if (!p_longname && parse_names) {
		/* we trash mode[0] here, it's ok */
		//tar.name[sizeof(tar.name)] = '\0'; - gcc 4.3.0 would complain
		tar.mode[0] = '\0';
		if (tar.prefix[0]) {
			/* and padding[0] */
			//tar.prefix[sizeof(tar.prefix)] = '\0'; - gcc 4.3.0 would complain
			tar.padding[0] = '\0';
			file_header->name = concat_path_file(tar.prefix, tar.name);
		} else
			file_header->name = xstrdup(tar.name);
	}

	/* Set bits 12-15 of the files mode */
	/* (typeflag was not trashed because chksum does not use getOctal) */
	switch (tar.typeflag) {
	/* busybox identifies hard links as being regular files with 0 size and a link name */
	case '1':
		file_header->mode |= S_IFREG;
		break;
	case '7':
	/* case 0: */
	case '0':
#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
		if (last_char_is(file_header->name, '/')) {
			goto set_dir;
		}
#endif
		file_header->mode |= S_IFREG;
		break;
	case '2':
		file_header->mode |= S_IFLNK;
		/* have seen tarballs with size field containing
		 * the size of the link target's name */
 size0:
		file_header->size = 0;
		break;
	case '3':
		file_header->mode |= S_IFCHR;
		goto size0; /* paranoia */
	case '4':
		file_header->mode |= S_IFBLK;
		goto size0;
	case '5':
 USE_FEATURE_TAR_OLDGNU_COMPATIBILITY(set_dir:)
		file_header->mode |= S_IFDIR;
		goto size0;
	case '6':
		file_header->mode |= S_IFIFO;
		goto size0;
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
	case 'L':
		/* free: paranoia: tar with several consecutive longnames */
		free(p_longname);
		/* For paranoia reasons we allocate extra NUL char */
		p_longname = xzalloc(file_header->size + 1);
		/* We read ASCIZ string, including NUL */
		xread(archive_handle->src_fd, p_longname, file_header->size);
		archive_handle->offset += file_header->size;
		/* return get_header_tar(archive_handle); */
		/* gcc 4.1.1 didn't optimize it into jump */
		/* so we will do it ourself, this also saves stack */
		goto again;
	case 'K':
		free(p_linkname);
		p_linkname = xzalloc(file_header->size + 1);
		xread(archive_handle->src_fd, p_linkname, file_header->size);
		archive_handle->offset += file_header->size;
		/* return get_header_tar(archive_handle); */
		goto again;
	case 'D':	/* GNU dump dir */
	case 'M':	/* Continuation of multi volume archive */
	case 'N':	/* Old GNU for names > 100 characters */
	case 'S':	/* Sparse file */
	case 'V':	/* Volume header */
#endif
	case 'g':	/* pax global header */
	case 'x': {	/* pax extended header */
		off_t sz;
		bb_error_msg("warning: skipping header '%c'", tar.typeflag);
		sz = (file_header->size + 511) & ~(off_t)511;
		archive_handle->offset += sz;
		sz >>= 9; /* sz /= 512 but w/o contortions for signed div */
		while (sz--)
			xread(archive_handle->src_fd, &tar, 512);
		/* return get_header_tar(archive_handle); */
		goto again_after_align;
	}
	default:
		bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag);
	}

#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
	if (p_longname) {
		file_header->name = p_longname;
		p_longname = NULL;
	}
	if (p_linkname) {
		file_header->link_target = p_linkname;
		p_linkname = NULL;
	}
#endif
	if (strncmp(file_header->name, "/../"+1, 3) == 0
	 || strstr(file_header->name, "/../")
	) {
		bb_error_msg_and_die("name with '..' encountered: '%s'",
				file_header->name);
	}

	/* Strip trailing '/' in directories */
	/* Must be done after mode is set as '/' is used to check if it's a directory */
	cp = last_char_is(file_header->name, '/');

	if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
		archive_handle->action_header(/*archive_handle->*/ file_header);
		/* Note that we kill the '/' only after action_header() */
		/* (like GNU tar 1.15.1: verbose mode outputs "dir/dir/") */
		if (cp) *cp = '\0';
		archive_handle->ah_flags |= ARCHIVE_EXTRACT_QUIET;
		archive_handle->action_data(archive_handle);
		llist_add_to(&(archive_handle->passed), file_header->name);
	} else {
		data_skip(archive_handle);
		free(file_header->name);
	}
	archive_handle->offset += file_header->size;

	free(file_header->link_target);
	/* Do not free(file_header->name)! (why?) */
#if ENABLE_FEATURE_TAR_UNAME_GNAME
	free(file_header->uname);
	free(file_header->gname);
#endif
	return EXIT_SUCCESS;
}
1	/* vi: set sw=4 ts=4: */
2	/* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
3	*
4	* FIXME:
5	* In privileged mode if uname and gname map to a uid and gid then use the
6	* mapped value instead of the uid/gid values in tar header
7	*
8	* References:
9	* GNU tar and star man pages,
10	* Opengroup's ustar interchange format,
11	* http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
12	*/
13
14	#include "libbb.h"
15	#include "unarchive.h"
16
17	/* NB: _DESTROYS_ str[len] character! */
18	static unsigned long long getOctal(char *str, int len)
19	{
20	unsigned long long v;
21	/* NB: leading spaces are allowed. Using strtoull to handle that.
22	* The downside is that we accept e.g. "-123" too :)
23	*/
24	str[len] = '\0';
25	v = strtoull(str, &str, 8);
26	if (str && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY \|\| str != ' '))
27	bb_error_msg_and_die("corrupted octal value in tar header");
28	return v;
29	}
30	#define GET_OCTAL(a) getOctal((a), sizeof(a))
31
32	void BUG_tar_header_size(void);
33	char FAST_FUNC get_header_tar(archive_handle_t *archive_handle)
34	{
35	file_header_t *file_header = archive_handle->file_header;
36	struct {
37	/* ustar header, Posix 1003.1 */
38	char name[100]; /* 0-99 */
39	char mode[8]; /* 100-107 */
40	char uid[8]; /* 108-115 */
41	char gid[8]; /* 116-123 */
42	char size[12]; /* 124-135 */
43	char mtime[12]; /* 136-147 */
44	char chksum[8]; /* 148-155 */
45	char typeflag; /* 156-156 */
46	char linkname[100]; /* 157-256 */
47	/* POSIX: "ustar" NUL "00" */
48	/* GNU tar: "ustar " NUL */
49	/* Normally it's defined as magic[6] followed by
50	* version[2], but we put them together to simplify code
51	*/
52	char magic[8]; /* 257-264 */
53	char uname[32]; /* 265-296 */
54	char gname[32]; /* 297-328 */
55	char devmajor[8]; /* 329-336 */
56	char devminor[8]; /* 337-344 */
57	char prefix[155]; /* 345-499 */
58	char padding[12]; /* 500-512 */
59	} tar;
60	char *cp;
61	int i, sum_u, sum;
62	#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
63	int sum_s;
64	#endif
65	int parse_names;
66
67	/* Our "private data" */
68	#define p_end ((smallint )(&archive_handle->ah_priv[0]))
69	#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
70	#define p_longname ((char *)(&archive_handle->ah_priv[1]))
71	#define p_linkname ((char *)(&archive_handle->ah_priv[2]))
72	#else
73	#define p_longname 0
74	#define p_linkname 0
75	#endif
76	// if (!archive_handle->ah_priv_inited) {
77	// archive_handle->ah_priv_inited = 1;
78	// p_end = 0;
79	// USE_FEATURE_TAR_GNU_EXTENSIONS(p_longname = NULL;)
80	// USE_FEATURE_TAR_GNU_EXTENSIONS(p_linkname = NULL;)
81	// }
82
83	if (sizeof(tar) != 512)
84	BUG_tar_header_size();
85
86	#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
87	again:
88	#endif
89	/* Align header */
90	data_align(archive_handle, 512);
91
92	again_after_align:
93
94	#if ENABLE_DESKTOP \|\| ENABLE_FEATURE_TAR_AUTODETECT
95	/* to prevent misdetection of bz2 sig */
96	(uint32_t)(&tar) = 0;
97	i = full_read(archive_handle->src_fd, &tar, 512);
98	/* If GNU tar sees EOF in above read, it says:
99	* "tar: A lone zero block at N", where N = kilobyte
100	* where EOF was met (not EOF block, actual EOF!),
101	* and exits with EXIT_SUCCESS.
102	* We will mimic exit(EXIT_SUCCESS), although we will not mimic
103	* the message and we don't check whether we indeed
104	* saw zero block directly before this. */
105	if (i == 0) {
106	xfunc_error_retval = 0;
107	short_read:
108	bb_error_msg_and_die("short read");
109	}
110	if (i != 512) {
111	USE_FEATURE_TAR_AUTODETECT(goto autodetect;)
112	goto short_read;
113	}
114
115	#else
116	i = 512;
117	xread(archive_handle->src_fd, &tar, i);
118	#endif
119	archive_handle->offset += i;
120
121	/* If there is no filename its an empty header */
122	if (tar.name[0] == 0 && tar.prefix[0] == 0) {
123	if (p_end) {
124	/* Second consecutive empty header - end of archive.
125	* Read until the end to empty the pipe from gz or bz2
126	*/
127	while (full_read(archive_handle->src_fd, &tar, 512) == 512)
128	continue;
129	return EXIT_FAILURE;
130	}
131	p_end = 1;
132	return EXIT_SUCCESS;
133	}
134	p_end = 0;
135
136	/* Check header has valid magic, "ustar" is for the proper tar,
137	* five NULs are for the old tar format */
138	if (strncmp(tar.magic, "ustar", 5) != 0
139	&& (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
140	\|\| memcmp(tar.magic, "\0\0\0\0", 5) != 0)
141	) {
142	#if ENABLE_FEATURE_TAR_AUTODETECT
143	char FAST_FUNC (get_header_ptr)(archive_handle_t );
144
145	autodetect:
146	/* tar gz/bz autodetect: check for gz/bz2 magic.
147	* If we see the magic, and it is the very first block,
148	* we can switch to get_header_tar_gz/bz2/lzma().
149	* Needs seekable fd. I wish recv(MSG_PEEK) works
150	* on any fd... */
151	#if ENABLE_FEATURE_SEAMLESS_GZ
152	if (tar.name[0] == 0x1f && tar.name[1] == (char)0x8b) { /* gzip */
153	get_header_ptr = get_header_tar_gz;
154	} else
155	#endif
156	#if ENABLE_FEATURE_SEAMLESS_BZ2
157	if (tar.name[0] == 'B' && tar.name[1] == 'Z'
158	&& tar.name[2] == 'h' && isdigit(tar.name[3])
159	) { /* bzip2 */
160	get_header_ptr = get_header_tar_bz2;
161	} else
162	#endif
163	goto err;
164	/* Two different causes for lseek() != 0:
165	* unseekable fd (would like to support that too, but...),
166	* or not first block (false positive, it's not .gz/.bz2!) */
167	if (lseek(archive_handle->src_fd, -i, SEEK_CUR) != 0)
168	goto err;
169	while (get_header_ptr(archive_handle) == EXIT_SUCCESS)
170	continue;
171	return EXIT_FAILURE;
172	err:
173	#endif /* FEATURE_TAR_AUTODETECT */
174	bb_error_msg_and_die("invalid tar magic");
175	}
176
177	/* Do checksum on headers.
178	* POSIX says that checksum is done on unsigned bytes, but
179	* Sun and HP-UX gets it wrong... more details in
180	* GNU tar source. */
181	#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
182	sum_s = ' ' * sizeof(tar.chksum);
183	#endif
184	sum_u = ' ' * sizeof(tar.chksum);
185	for (i = 0; i < 148; i++) {
186	sum_u += ((unsigned char*)&tar)[i];
187	#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
188	sum_s += ((signed char*)&tar)[i];
189	#endif
190	}
191	for (i = 156; i < 512; i++) {
192	sum_u += ((unsigned char*)&tar)[i];
193	#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
194	sum_s += ((signed char*)&tar)[i];
195	#endif
196	}
197	#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
198	sum = strtoul(tar.chksum, &cp, 8);
199	if ((cp && cp != ' ')
200	\|\| (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum))
201	) {
202	bb_error_msg_and_die("invalid tar header checksum");
203	}
204	#else
205	/* This field does not need special treatment (getOctal) */
206	sum = xstrtoul(tar.chksum, 8);
207	if (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) {
208	bb_error_msg_and_die("invalid tar header checksum");
209	}
210	#endif
211
212	/* 0 is reserved for high perf file, treat as normal file */
213	if (!tar.typeflag) tar.typeflag = '0';
214	parse_names = (tar.typeflag >= '0' && tar.typeflag <= '7');
215
216	/* getOctal trashes subsequent field, therefore we call it
217	* on fields in reverse order */
218	if (tar.devmajor[0]) {
219	char t = tar.prefix[0];
220	/* we trash prefix[0] here, but we DO need it later! */
221	unsigned minor = GET_OCTAL(tar.devminor);
222	unsigned major = GET_OCTAL(tar.devmajor);
223	file_header->device = makedev(major, minor);
224	tar.prefix[0] = t;
225	}
226	file_header->link_target = NULL;
227	if (!p_linkname && parse_names && tar.linkname[0]) {
228	file_header->link_target = xstrndup(tar.linkname, sizeof(tar.linkname));
229	/* FIXME: what if we have non-link object with link_target? */
230	/* Will link_target be free()ed? */
231	}
232	#if ENABLE_FEATURE_TAR_UNAME_GNAME
233	file_header->uname = tar.uname[0] ? xstrndup(tar.uname, sizeof(tar.uname)) : NULL;
234	file_header->gname = tar.gname[0] ? xstrndup(tar.gname, sizeof(tar.gname)) : NULL;
235	#endif
236	file_header->mtime = GET_OCTAL(tar.mtime);
237	file_header->size = GET_OCTAL(tar.size);
238	file_header->gid = GET_OCTAL(tar.gid);
239	file_header->uid = GET_OCTAL(tar.uid);
240	/* Set bits 0-11 of the files mode */
241	file_header->mode = 07777 & GET_OCTAL(tar.mode);
242
243	file_header->name = NULL;
244	if (!p_longname && parse_names) {
245	/* we trash mode[0] here, it's ok */
246	//tar.name[sizeof(tar.name)] = '\0'; - gcc 4.3.0 would complain
247	tar.mode[0] = '\0';
248	if (tar.prefix[0]) {
249	/* and padding[0] */
250	//tar.prefix[sizeof(tar.prefix)] = '\0'; - gcc 4.3.0 would complain
251	tar.padding[0] = '\0';
252	file_header->name = concat_path_file(tar.prefix, tar.name);
253	} else
254	file_header->name = xstrdup(tar.name);
255	}
256
257	/* Set bits 12-15 of the files mode */
258	/* (typeflag was not trashed because chksum does not use getOctal) */
259	switch (tar.typeflag) {
260	/* busybox identifies hard links as being regular files with 0 size and a link name */
261	case '1':
262	file_header->mode \|= S_IFREG;
263	break;
264	case '7':
265	/* case 0: */
266	case '0':
267	#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
268	if (last_char_is(file_header->name, '/')) {
269	goto set_dir;
270	}
271	#endif
272	file_header->mode \|= S_IFREG;
273	break;
274	case '2':
275	file_header->mode \|= S_IFLNK;
276	/* have seen tarballs with size field containing
277	* the size of the link target's name */
278	size0:
279	file_header->size = 0;
280	break;
281	case '3':
282	file_header->mode \|= S_IFCHR;
283	goto size0; /* paranoia */
284	case '4':
285	file_header->mode \|= S_IFBLK;
286	goto size0;
287	case '5':
288	USE_FEATURE_TAR_OLDGNU_COMPATIBILITY(set_dir:)
289	file_header->mode \|= S_IFDIR;
290	goto size0;
291	case '6':
292	file_header->mode \|= S_IFIFO;
293	goto size0;
294	#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
295	case 'L':
296	/* free: paranoia: tar with several consecutive longnames */
297	free(p_longname);
298	/* For paranoia reasons we allocate extra NUL char */
299	p_longname = xzalloc(file_header->size + 1);
300	/* We read ASCIZ string, including NUL */
301	xread(archive_handle->src_fd, p_longname, file_header->size);
302	archive_handle->offset += file_header->size;
303	/* return get_header_tar(archive_handle); */
304	/* gcc 4.1.1 didn't optimize it into jump */
305	/* so we will do it ourself, this also saves stack */
306	goto again;
307	case 'K':
308	free(p_linkname);
309	p_linkname = xzalloc(file_header->size + 1);
310	xread(archive_handle->src_fd, p_linkname, file_header->size);
311	archive_handle->offset += file_header->size;
312	/* return get_header_tar(archive_handle); */
313	goto again;
314	case 'D': /* GNU dump dir */
315	case 'M': /* Continuation of multi volume archive */
316	case 'N': /* Old GNU for names > 100 characters */
317	case 'S': /* Sparse file */
318	case 'V': /* Volume header */
319	#endif
320	case 'g': /* pax global header */
321	case 'x': { /* pax extended header */
322	off_t sz;
323	bb_error_msg("warning: skipping header '%c'", tar.typeflag);
324	sz = (file_header->size + 511) & ~(off_t)511;
325	archive_handle->offset += sz;
326	sz >>= 9; /* sz /= 512 but w/o contortions for signed div */
327	while (sz--)
328	xread(archive_handle->src_fd, &tar, 512);
329	/* return get_header_tar(archive_handle); */
330	goto again_after_align;
331	}
332	default:
333	bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag);
334	}
335
336	#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
337	if (p_longname) {
338	file_header->name = p_longname;
339	p_longname = NULL;
340	}
341	if (p_linkname) {
342	file_header->link_target = p_linkname;
343	p_linkname = NULL;
344	}
345	#endif
346	if (strncmp(file_header->name, "/../"+1, 3) == 0
347	\|\| strstr(file_header->name, "/../")
348	) {
349	bb_error_msg_and_die("name with '..' encountered: '%s'",
350	file_header->name);
351	}
352
353	/* Strip trailing '/' in directories */
354	/* Must be done after mode is set as '/' is used to check if it's a directory */
355	cp = last_char_is(file_header->name, '/');
356
357	if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
358	archive_handle->action_header(/archive_handle->/ file_header);
359	/* Note that we kill the '/' only after action_header() */
360	/* (like GNU tar 1.15.1: verbose mode outputs "dir/dir/") */
361	if (cp) *cp = '\0';
362	archive_handle->ah_flags \|= ARCHIVE_EXTRACT_QUIET;
363	archive_handle->action_data(archive_handle);
364	llist_add_to(&(archive_handle->passed), file_header->name);
365	} else {
366	data_skip(archive_handle);
367	free(file_header->name);
368	}
369	archive_handle->offset += file_header->size;
370
371	free(file_header->link_target);
372	/* Do not free(file_header->name)! (why?) */
373	#if ENABLE_FEATURE_TAR_UNAME_GNAME
374	free(file_header->uname);
375	free(file_header->gname);
376	#endif
377	return EXIT_SUCCESS;
378	}