path: root/archival/libarchive/open_transformer.c (plain)
blob: 19866304196dbfe8b474ce3f8732ac7790f14e1c

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 init_transformer_aux_data(transformer_aux_data_t *aux)
10	{
11	memset(aux, 0, sizeof(*aux));
12	}
13
14	int FAST_FUNC check_signature16(transformer_aux_data_t *aux, int src_fd, unsigned magic16)
15	{
16	if (aux && aux->check_signature) {
17	uint16_t magic2;
18	if (full_read(src_fd, &magic2, 2) != 2 || magic2 != magic16) {
19	bb_error_msg("invalid magic");
20	#if 0 /* possible future extension */
21	if (aux->check_signature > 1)
22	xfunc_die();
23	#endif
24	return -1;
25	}
26	}
27	return 0;
28	}
29
30	void check_errors_in_children(int signo)
31	{
32	int status;
33
34	if (!signo) {
35	/* block waiting for any child */
36	if (wait(&status) < 0)
37	//FIXME: check EINTR?
38	return; /* probably there are no children */
39	goto check_status;
40	}
41
42	/* Wait for any child without blocking */
43	for (;;) {
44	if (wait_any_nohang(&status) < 0)
45	//FIXME: check EINTR?
46	/* wait failed?! I'm confused... */
47	return;
48	check_status:
49	/*if (WIFEXITED(status) && WEXITSTATUS(status) == 0)*/
50	/* On Linux, the above can be checked simply as: */
51	if (status == 0)
52	/* this child exited with 0 */
53	continue;
54	/* Cannot happen:
55	if (!WIFSIGNALED(status) && !WIFEXITED(status)) ???;
56	*/
57	bb_got_signal = 1;
58	}
59	}
60
61	/* transformer(), more than meets the eye */
62	#if BB_MMU
63	void FAST_FUNC open_transformer(int fd,
64	int check_signature,
65	IF_DESKTOP(long long) int FAST_FUNC (*transformer)(transformer_aux_data_t *aux, int src_fd, int dst_fd)
66	)
67	#else
68	void FAST_FUNC open_transformer(int fd, const char *transform_prog)
69	#endif
70	{
71	struct fd_pair fd_pipe;
72	int pid;
73
74	xpiped_pair(fd_pipe);
75	pid = BB_MMU ? xfork() : xvfork();
76	if (pid == 0) {
77	/* Child */
78	close(fd_pipe.rd); /* we don't want to read from the parent */
79	// FIXME: error check?
80	#if BB_MMU
81	{
82	IF_DESKTOP(long long) int r;
83	transformer_aux_data_t aux;
84	init_transformer_aux_data(&aux);
85	aux.check_signature = check_signature;
86	r = transformer(&aux, fd, fd_pipe.wr);
87	if (ENABLE_FEATURE_CLEAN_UP) {
88	close(fd_pipe.wr); /* send EOF */
89	close(fd);
90	}
91	/* must be _exit! bug was actually seen here */
92	_exit(/*error if:*/ r < 0);
93	}
94	#else
95	{
96	char *argv[4];
97	xmove_fd(fd, 0);
98	xmove_fd(fd_pipe.wr, 1);
99	argv[0] = (char*)transform_prog;
100	argv[1] = (char*)"-cf";
101	argv[2] = (char*)"-";
102	argv[3] = NULL;
103	BB_EXECVP(transform_prog, argv);
104	bb_perror_msg_and_die("can't execute '%s'", transform_prog);
105	}
106	#endif
107	/* notreached */
108	}
109
110	/* parent process */
111	close(fd_pipe.wr); /* don't want to write to the child */
112	xmove_fd(fd_pipe.rd, fd);
113	}
114
115
116	#if SEAMLESS_COMPRESSION
117
118	/* Used by e.g. rpm which gives us a fd without filename,
119	* thus we can't guess the format from filename's extension.
120	*/
121	int FAST_FUNC setup_unzip_on_fd(int fd, int fail_if_not_compressed)
122	{
123	union {
124	uint8_t b[4];
125	uint16_t b16[2];
126	uint32_t b32[1];
127	} magic;
128	int offset = -2;
129	USE_FOR_MMU(IF_DESKTOP(long long) int FAST_FUNC (*xformer)(transformer_aux_data_t *aux, int src_fd, int dst_fd);)
130	USE_FOR_NOMMU(const char *xformer_prog;)
131
132	/* .gz and .bz2 both have 2-byte signature, and their
133	* unpack_XXX_stream wants this header skipped. */
134	xread(fd, magic.b16, sizeof(magic.b16[0]));
135	if (ENABLE_FEATURE_SEAMLESS_GZ
136	&& magic.b16[0] == GZIP_MAGIC
137	) {
138	USE_FOR_MMU(xformer = unpack_gz_stream;)
139	USE_FOR_NOMMU(xformer_prog = "gunzip";)
140	goto found_magic;
141	}
142	if (ENABLE_FEATURE_SEAMLESS_BZ2
143	&& magic.b16[0] == BZIP2_MAGIC
144	) {
145	USE_FOR_MMU(xformer = unpack_bz2_stream;)
146	USE_FOR_NOMMU(xformer_prog = "bunzip2";)
147	goto found_magic;
148	}
149	if (ENABLE_FEATURE_SEAMLESS_XZ
150	&& magic.b16[0] == XZ_MAGIC1
151	) {
152	offset = -6;
153	xread(fd, magic.b32, sizeof(magic.b32[0]));
154	if (magic.b32[0] == XZ_MAGIC2) {
155	USE_FOR_MMU(xformer = unpack_xz_stream;)
156	USE_FOR_NOMMU(xformer_prog = "unxz";)
157	goto found_magic;
158	}
159	}
160
161	/* No known magic seen */
162	if (fail_if_not_compressed)
163	bb_error_msg_and_die("no gzip"
164	IF_FEATURE_SEAMLESS_BZ2("/bzip2")
165	IF_FEATURE_SEAMLESS_XZ("/xz")
166	" magic");
167	xlseek(fd, offset, SEEK_CUR);
168	return 1;
169
170	found_magic:
171	# if BB_MMU
172	open_transformer_with_no_sig(fd, xformer);
173	# else
174	/* NOMMU version of open_transformer execs
175	* an external unzipper that wants
176	* file position at the start of the file */
177	xlseek(fd, offset, SEEK_CUR);
178	open_transformer_with_sig(fd, xformer, xformer_prog);
179	# endif
180	return 0;
181	}
182
183	int FAST_FUNC open_zipped(const char *fname, int fail_if_not_compressed)
184	{
185	int fd;
186
187	fd = open(fname, O_RDONLY);
188	if (fd < 0)
189	return fd;
190
191	if (ENABLE_FEATURE_SEAMLESS_LZMA) {
192	/* .lzma has no header/signature, can only detect it by extension */
193	char *sfx = strrchr(fname, '.');
194	if (sfx && strcmp(sfx+1, "lzma") == 0) {
195	open_transformer_with_sig(fd, unpack_lzma_stream, "unlzma");
196	return fd;
197	}
198	}
199	if ((ENABLE_FEATURE_SEAMLESS_GZ)
200	|| (ENABLE_FEATURE_SEAMLESS_BZ2)
201	|| (ENABLE_FEATURE_SEAMLESS_XZ)
202	) {
203	setup_unzip_on_fd(fd, fail_if_not_compressed);
204	}
205
206	return fd;
207	}
208
209	#endif /* SEAMLESS_COMPRESSION */
210
211	void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
212	{
213	int fd;
214	char *image;
215
216	fd = open_zipped(fname, /*fail_if_not_compressed:*/ 0);
217	if (fd < 0)
218	return NULL;
219
220	image = xmalloc_read(fd, maxsz_p);
221	if (!image)
222	bb_perror_msg("read error from '%s'", fname);
223	close(fd);
224
225	return image;
226	}
227