rpm2cpio: teach it to understand xz format

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/archival/rpm2cpio.c b/archival/rpm2cpio.c
index 4ed5b023be2147b9ffae5dd25aded81dfceec039..598ec8670570952a32f2103fe9edf925e303b9c2 100644 (file)
--- a/archival/rpm2cpio.c
+++ b/archival/rpm2cpio.c
@@ -68,22 +68,35 @@ int rpm2cpio_main(int argc UNUSED_PARAM, char **argv)
 #else
        /* BLOAT */
        {
-               unsigned char magic[2];
+               unsigned char magic[8];
                IF_DESKTOP(long long) int FAST_FUNC (*unpack)(int src_fd, int dst_fd);
 
                xread(rpm_fd, &magic, 2);
-               unpack = unpack_gz_stream;
-               if (magic[0] != 0x1f || magic[1] != 0x8b) {
-                       if (!ENABLE_FEATURE_SEAMLESS_BZ2
-                        || magic[0] != 'B' || magic[1] != 'Z'
-                       ) {
-                               bb_error_msg_and_die("invalid gzip"
-                                               IF_FEATURE_SEAMLESS_BZ2("/bzip2")
-                                               " magic");
-                       }
+               if (magic[0] == 0x1f && magic[1] == 0x8b) {
+                       unpack = unpack_gz_stream;
+               } else
+               if (ENABLE_FEATURE_SEAMLESS_BZ2
+                && magic[0] == 'B' && magic[1] == 'Z'
+               ) {
                        unpack = unpack_bz2_stream;
+               } else
+               if (ENABLE_FEATURE_SEAMLESS_XZ
+                && magic[0] == 0xfd && magic[1] == '7'
+               ) {
+                       /* .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)
+                               goto no_magic;
+                       xlseek(rpm_fd, -6, SEEK_CUR);
+                       unpack = unpack_xz_stream;
+               } else {
+ no_magic:
+                       bb_error_msg_and_die("no gzip"
+                                       IF_FEATURE_SEAMLESS_BZ2("/bzip2")
+                                       IF_FEATURE_SEAMLESS_XZ("/xz")
+                                       " magic");
                }
-
                if (unpack(rpm_fd, STDOUT_FILENO) < 0)
                        bb_error_msg_and_die("error unpacking");
        }