summaryrefslogtreecommitdiff
path: root/archival/libarchive/open_transformer.c
blob: 743ffee0207e97f0639fc8299cc89f13d1791634 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
/* vi: set sw=4 ts=4: */
/*
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

#include "libbb.h"
#include "bb_archive.h"

#define ZIPPED (ENABLE_FEATURE_SEAMLESS_LZMA \
	|| ENABLE_FEATURE_SEAMLESS_BZ2 \
	|| ENABLE_FEATURE_SEAMLESS_GZ \
	/* || ENABLE_FEATURE_SEAMLESS_Z */ \
)

#if ZIPPED
# include "bb_archive.h"
#endif

/* transformer(), more than meets the eye */
/*
 * On MMU machine, the transform_prog is removed by macro magic
 * in include/archive.h. On NOMMU, transformer is removed.
 */
void FAST_FUNC open_transformer(int fd,
	IF_DESKTOP(long long) int FAST_FUNC (*transformer)(int src_fd, int dst_fd),
	const char *transform_prog)
{
	struct fd_pair fd_pipe;
	int pid;

	xpiped_pair(fd_pipe);
	pid = BB_MMU ? xfork() : xvfork();
	if (pid == 0) {
		/* Child */
		close(fd_pipe.rd); /* we don't want to read from the parent */
		// FIXME: error check?
#if BB_MMU
		transformer(fd, fd_pipe.wr);
		if (ENABLE_FEATURE_CLEAN_UP) {
			close(fd_pipe.wr); /* send EOF */
			close(fd);
		}
		/* must be _exit! bug was actually seen here */
		_exit(EXIT_SUCCESS);
#else
		{
			char *argv[4];
			xmove_fd(fd, 0);
			xmove_fd(fd_pipe.wr, 1);
			argv[0] = (char*)transform_prog;
			argv[1] = (char*)"-cf";
			argv[2] = (char*)"-";
			argv[3] = NULL;
			BB_EXECVP(transform_prog, argv);
			bb_perror_msg_and_die("can't execute '%s'", transform_prog);
		}
#endif
		/* notreached */
	}

	/* parent process */
	close(fd_pipe.wr); /* don't want to write to the child */
	xmove_fd(fd_pipe.rd, fd);
}


/* Used by e.g. rpm which gives us a fd without filename,
 * thus we can't guess the format from filename's extension.
 */
#if ZIPPED
void FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
{
	const int fail_if_not_detected = 1;
	union {
		uint8_t b[4];
		uint16_t b16[2];
		uint32_t b32[1];
	} magic;
	int offset = -2;
# if BB_MMU
	IF_DESKTOP(long long) int FAST_FUNC (*xformer)(int src_fd, int dst_fd);
	enum { xformer_prog = 0 };
# else
	enum { xformer = 0 };
	const char *xformer_prog;
# endif

	/* .gz and .bz2 both have 2-byte signature, and their
	 * unpack_XXX_stream wants this header skipped. */
	xread(fd, magic.b16, sizeof(magic.b16[0]));
	if (ENABLE_FEATURE_SEAMLESS_GZ
	 && magic.b16[0] == GZIP_MAGIC
	) {
# if BB_MMU
		xformer = unpack_gz_stream;
# else
		xformer_prog = "gunzip";
# endif
		goto found_magic;
	}
	if (ENABLE_FEATURE_SEAMLESS_BZ2
	 && magic.b16[0] == BZIP2_MAGIC
	) {
# if BB_MMU
		xformer = unpack_bz2_stream;
# else
		xformer_prog = "bunzip2";
# endif
		goto found_magic;
	}
	if (ENABLE_FEATURE_SEAMLESS_XZ
	 && magic.b16[0] == XZ_MAGIC1
	) {
		offset = -6;
		xread(fd, magic.b32, sizeof(magic.b32[0]));
		if (magic.b32[0] == XZ_MAGIC2) {
# if BB_MMU
			xformer = unpack_xz_stream;
			/* unpack_xz_stream wants fd at position 6, no need to seek */
			//xlseek(fd, offset, SEEK_CUR);
# else
			xformer_prog = "unxz";
# endif
			goto found_magic;
		}
	}

	/* No known magic seen */
	if (fail_if_not_detected)
		bb_error_msg_and_die("no gzip"
			IF_FEATURE_SEAMLESS_BZ2("/bzip2")
			IF_FEATURE_SEAMLESS_XZ("/xz")
			" magic");
	xlseek(fd, offset, SEEK_CUR);
	return;

 found_magic:
# if !BB_MMU
	/* NOMMU version of open_transformer execs
	 * an external unzipper that wants
	 * file position at the start of the file */
	xlseek(fd, offset, SEEK_CUR);
# endif
	open_transformer(fd, xformer, xformer_prog);
}
#endif /* ZIPPED */

int FAST_FUNC open_zipped(const char *fname)
{
#if !ZIPPED
	return open(fname, O_RDONLY);
#else
	char *sfx;
	int fd;

	fd = open(fname, O_RDONLY);
	if (fd < 0)
		return fd;

	sfx = strrchr(fname, '.');
	if (sfx) {
		sfx++;
		if (ENABLE_FEATURE_SEAMLESS_LZMA && strcmp(sfx, "lzma") == 0)
			/* .lzma has no header/signature, just trust it */
			open_transformer(fd, unpack_lzma_stream, "unlzma");
		else
		if ((ENABLE_FEATURE_SEAMLESS_GZ && strcmp(sfx, "gz") == 0)
		 || (ENABLE_FEATURE_SEAMLESS_BZ2 && strcmp(sfx, "bz2") == 0)
		 || (ENABLE_FEATURE_SEAMLESS_XZ && strcmp(sfx, "xz") == 0)
		) {
			setup_unzip_on_fd(fd /*, fail_if_not_detected: 1*/);
		}
	}

	return fd;
#endif
}

void* FAST_FUNC xmalloc_open_zipped_read_close(const char *fname, size_t *maxsz_p)
{
	int fd;
	char *image;

	fd = open_zipped(fname);
	if (fd < 0)
		return NULL;

	image = xmalloc_read(fd, maxsz_p);
	if (!image)
		bb_perror_msg("read error from '%s'", fname);
	close(fd);

	return image;
}