diff options
Diffstat (limited to 'busybox/archival/libunarchive/check_header_gzip.c')
-rw-r--r-- | busybox/archival/libunarchive/check_header_gzip.c | 57 |
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; +} |