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26b6ccf34

Denys Vlasenko

2010-06-02

FAILED Duration: 27s

Subject

*: simplify checks for gz/bz2/xz magic

Binary

No binary (build failed)

Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

archival/rpm2cpio.c +12 -7 include/unarchive.h +16 -0 libbb/read.c +13 -8

archival/rpm2cpio.c+12 -7

@@ -68,26 +68,31 @@ int rpm2cpio_main(int argc UNUSED_PARAM, char **argv)
	#else
	/* BLOAT */
	{
-	unsigned char magic[8];
+	union {
+	uint8_t b[4];
+	uint16_t b16[2];
+	uint32_t b32[1];
+	} magic;
	IF_DESKTOP(long long) int FAST_FUNC (*unpack)(int src_fd, int dst_fd);

-	xread(rpm_fd, &magic, 2);
-	if (magic[0] == 0x1f && magic[1] == 0x8b) {
+	xread(rpm_fd, magic.b16, sizeof(magic.b16));
+	if (magic.b16[0] == GZIP_MAGIC) {
	unpack = unpack_gz_stream;
	} else
	if (ENABLE_FEATURE_SEAMLESS_BZ2
-	&& magic[0] == 'B' && magic[1] == 'Z'
+	&& magic.b16[0] == BZIP2_MAGIC
	) {
	unpack = unpack_bz2_stream;
	} else
	if (ENABLE_FEATURE_SEAMLESS_XZ
-	&& magic[0] == 0xfd && magic[1] == '7'
+	&& magic.b16[0] == XZ_MAGIC1
	) {
	/* .xz signature: 0xfd, '7', 'z', 'X', 'Z', 0x00 */
	/* More info at: http://tukaani.org/xz/xz-file-format.txt */
-	xread(rpm_fd, magic + 2, 4);
-	if (strcmp((char*)magic + 2, "zXZ") != 0)
+	xread(rpm_fd, magic.b32, sizeof(magic.b32));
+	if (magic.b32[0] != XZ_MAGIC2)
	goto no_magic;
+	/* unpack_xz_stream wants fd at position 0 */
	xlseek(rpm_fd, -6, SEEK_CUR);
	unpack = unpack_xz_stream;
	} else {

include/unarchive.h+16 -0

@@ -4,6 +4,22 @@

	PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN

+	enum {
+	#if BB_BIG_ENDIAN
+	COMPRESS_MAGIC = 0x1f9d,
+	GZIP_MAGIC = 0x1f8b,
+	BZIP2_MAGIC = ('B'<<8) + 'Z',
+	XZ_MAGIC1 = (0xfd<<8) + '7',
+	XZ_MAGIC2 = ((((('z'<<8) + 'X')<<8) + 'Z')<<8) + 0,
+	#else
+	COMPRESS_MAGIC = 0x9d1f,
+	GZIP_MAGIC = 0x8b1f,
+	BZIP2_MAGIC = ('Z'<<8) + 'B',
+	XZ_MAGIC1 = ('7'<<8) + 0xfd,
+	XZ_MAGIC2 = (((((0<<8) + 'Z')<<8) + 'X')<<8) + 'z',
+	#endif
+	};
+
	typedef struct file_header_t {
	char *name;
	char *link_target;

libbb/read.c+13 -8

@@ -312,7 +312,11 @@ void* FAST_FUNC xmalloc_xopen_read_close(const char filename, size_t maxsz_p)
	void FAST_FUNC setup_unzip_on_fd(int fd /, int fail_if_not_detected/)
	{
	const int fail_if_not_detected = 1;
-	unsigned char magic[8];
+	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);
@@ -324,9 +328,9 @@ void FAST_FUNC setup_unzip_on_fd(int fd /, int fail_if_not_detected/)

	/* .gz and .bz2 both have 2-byte signature, and their
	* unpack_XXX_stream wants this header skipped. */
-	xread(fd, magic, 2);
+	xread(fd, magic.b16, sizeof(magic.b16));
	if (ENABLE_FEATURE_SEAMLESS_GZ
-	&& magic[0] == 0x1f && magic[1] == 0x8b
+	&& magic.b16[0] == GZIP_MAGIC
	) {
	# if BB_MMU
	xformer = unpack_gz_stream;
@@ -336,7 +340,7 @@ void FAST_FUNC setup_unzip_on_fd(int fd /, int fail_if_not_detected/)
	goto found_magic;
	}
	if (ENABLE_FEATURE_SEAMLESS_BZ2
-	&& magic[0] == 'B' && magic[1] == 'Z'
+	&& magic.b16[0] == BZIP2_MAGIC
	) {
	# if BB_MMU
	xformer = unpack_bz2_stream;
@@ -346,19 +350,20 @@ void FAST_FUNC setup_unzip_on_fd(int fd /, int fail_if_not_detected/)
	goto found_magic;
	}
	if (ENABLE_FEATURE_SEAMLESS_XZ
-	&& magic[0] == 0xfd && magic[1] == '7'
+	&& magic.b16[0] == XZ_MAGIC1
	) {
	/* .xz signature: 0xfd, '7', 'z', 'X', 'Z', 0x00 */
	/* More info at: http://tukaani.org/xz/xz-file-format.txt */
	offset = -6;
-	xread(fd, magic + 2, 4);
-	if (strcmp((char*)magic + 2, "zXZ") == 0) {
+	xread(fd, magic.b32, sizeof(magic.b32));
+	if (magic.b32[0] == XZ_MAGIC2) {
	# if BB_MMU
	xformer = unpack_xz_stream;
+	/* unpack_xz_stream wants fd at position 0 */
+	xlseek(fd, offset, SEEK_CUR);
	# else
	xformer_prog = "unxz";
	# endif
-	xlseek(fd, offset, SEEK_CUR);
	goto found_magic;
	}
	}