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preparatory cleanups for seamless uncompression improvements

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unpack_gz_stream_with_info: fix buggy error check
man: fix possible accesses past the end of a string
move seamless uncompression helpers from read_printf.c to open_transformer.c

function                                             old     new   delta
show_manpage                                         153     212     +59
unpack_gz_stream_with_info                           520     539     +19

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2012-03-06 16:23:50 +01:00
parent 17eedcad94
commit 59655077c5
6 changed files with 187 additions and 179 deletions
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140
archival/libarchive/open_transformer.c
View File

@@ -6,6 +6,16 @@
#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
@@ -52,3 +62,133 @@ void FAST_FUNC open_transformer(int fd,
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;
}