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Diffstat (limited to 'busybox/archival/libunarchive/check_header_gzip.c')
-rw-r--r--busybox/archival/libunarchive/check_header_gzip.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/busybox/archival/libunarchive/check_header_gzip.c b/busybox/archival/libunarchive/check_header_gzip.c
new file mode 100644
index 0000000..13832c2
--- /dev/null
+++ b/busybox/archival/libunarchive/check_header_gzip.c
@@ -0,0 +1,57 @@
+#include <stdlib.h>
+#include <unistd.h>
+#include "libbb.h"
+
+extern void check_header_gzip(int src_fd)
+{
+ union {
+ unsigned char raw[8];
+ struct {
+ unsigned char method;
+ unsigned char flags;
+ unsigned int mtime;
+ unsigned char xtra_flags;
+ unsigned char os_flags;
+ } formated;
+ } header;
+
+ bb_xread_all(src_fd, header.raw, 8);
+
+ /* Check the compression method */
+ if (header.formated.method != 8) {
+ bb_error_msg_and_die("Unknown compression method %d",
+ header.formated.method);
+ }
+
+ if (header.formated.flags & 0x04) {
+ /* bit 2 set: extra field present */
+ unsigned char extra_short;
+
+ extra_short = bb_xread_char(src_fd) + (bb_xread_char(src_fd) << 8);
+ while (extra_short > 0) {
+ /* Ignore extra field */
+ bb_xread_char(src_fd);
+ extra_short--;
+ }
+ }
+
+ /* Discard original name if any */
+ if (header.formated.flags & 0x08) {
+ /* bit 3 set: original file name present */
+ while(bb_xread_char(src_fd) != 0);
+ }
+
+ /* Discard file comment if any */
+ if (header.formated.flags & 0x10) {
+ /* bit 4 set: file comment present */
+ while(bb_xread_char(src_fd) != 0);
+ }
+
+ /* Read the header checksum */
+ if (header.formated.flags & 0x02) {
+ bb_xread_char(src_fd);
+ bb_xread_char(src_fd);
+ }
+
+ return;
+}