45f66167f

Denys Vlasenko

2010-07-01

FAILED Duration: 40s

Subject

xz compression detection: avoid the need to seek

No binary (build failed)

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

—

(log yok)

archival/bbunzip.c+9 -0

@@ -373,6 +373,15 @@ int unlzma_main(int argc UNUSED_PARAM, char **argv)
	static
	IF_DESKTOP(long long) int FAST_FUNC unpack_unxz(unpack_info_t *info UNUSED_PARAM)
	{
+	struct {
+	uint32_t v1;
+	uint16_t v2;
+	} magic;
+	xread(STDIN_FILENO, &magic, 6);
+	if (magic.v1 != XZ_MAGIC1a \|\| magic.v2 != XZ_MAGIC2a) {
+	bb_error_msg("invalid magic");
+	return -1;
+	}
	return unpack_xz_stream(STDIN_FILENO, STDOUT_FILENO);
	}
	int unxz_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;

archival/libunarchive/decompress_unxz.c+3 -1

@@ -56,9 +56,11 @@ unpack_xz_stream(int src_fd, int dst_fd)
	if (!crc32_table)
	crc32_table = crc32_filltable(NULL, /endian:/ 0);

-	membuf = xmalloc(2 * BUFSIZ);
	memset(&iobuf, 0, sizeof(iobuf));
+	/* Preload XZ file signature */
+	membuf = (void) strcpy(xmalloc(2 BUFSIZ), HEADER_MAGIC);
	iobuf.in = membuf;
+	iobuf.in_size = HEADER_MAGIC_SIZE;
	iobuf.out = membuf + BUFSIZ;
	iobuf.out_size = BUFSIZ;

archival/rpm2cpio.c+2 -2

@@ -92,8 +92,8 @@ int rpm2cpio_main(int argc UNUSED_PARAM, char **argv)
	xread(rpm_fd, magic.b32, sizeof(magic.b32[0]));
	if (magic.b32[0] != XZ_MAGIC2)
	goto no_magic;
-	/* unpack_xz_stream wants fd at position 0 */
-	xlseek(rpm_fd, -6, SEEK_CUR);
+	/* unpack_xz_stream wants fd at position 6, no need to seek */
+	//xlseek(rpm_fd, -6, SEEK_CUR);
	unpack = unpack_xz_stream;
	} else {
	no_magic:

include/unarchive.h+14 -9

@@ -7,16 +7,21 @@ 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,
+	GZIP_MAGIC = 0x1f8b,
+	BZIP2_MAGIC = 'B' * 256 + 'Z',
+	XZ_MAGIC1 = 0xfd * 256 + '7',
+	XZ_MAGIC2 = (('z' * 256 + 'X') * 256 + 'Z') * 256 + 0,
+	/* Different form: 32 bits, then 16 bits: */
+	XZ_MAGIC1a = ((0xfd * 256 + '7') * 256 + 'z') * 256 + 'X',
+	XZ_MAGIC2a = 'Z' * 256 + 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',
+	GZIP_MAGIC = 0x8b1f,
+	BZIP2_MAGIC = 'Z' * 256 + 'B',
+	XZ_MAGIC1 = '7' * 256 + 0xfd,
+	XZ_MAGIC2 = ((0 * 256 + 'Z') * 256 + 'X') * 256 + 'z',
+	XZ_MAGIC1a = (('X' * 256 + 'z') * 256 + '7') * 256 + 0xfd,
+	XZ_MAGIC2a = 0 * 256 + 'Z',
	#endif
	};

@@ -196,7 +201,7 @@ typedef struct inflate_unzip_result {
	} inflate_unzip_result;

	IF_DESKTOP(long long) int inflate_unzip(inflate_unzip_result *res, off_t compr_size, int src_fd, int dst_fd) FAST_FUNC;
-	/* xz unpacker takes .xz stream from offset 0 */
+	/* xz unpacker takes .xz stream from offset 6 */
	IF_DESKTOP(long long) int unpack_xz_stream(int src_fd, int dst_fd) FAST_FUNC;
	/* lzma unpacker takes .lzma stream from offset 0 */
	IF_DESKTOP(long long) int unpack_lzma_stream(int src_fd, int dst_fd) FAST_FUNC;

libbb/read_printf.c+2 -2

@@ -296,8 +296,8 @@ void FAST_FUNC setup_unzip_on_fd(int fd /, int fail_if_not_detected/)
	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);
+	/* unpack_xz_stream wants fd at position 6, no need to seek */
+	//xlseek(fd, offset, SEEK_CUR);
	# else
	xformer_prog = "unxz";
	# endif