1 files changed, 69 insertions, 0 deletions

diff --git a/src/extractblocks.c b/src/extractblocks.c
new file mode 100644
index 0000000..51505ef
--- /dev/null
+++ b/src/extractblocks.c
@@ -0,0 +1,69 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <strings.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+int main( int args, char **argv )
+{
+  int            toindex;
+  int            i, run = 1, filenum = 0, offset = 0, oldoffset = -1;
+  struct stat    fstatus;
+  unsigned char *mappedfile;
+
+  if( args != 2 )
+    { fputs( "Missing filenames.", stderr ); exit( 1 ); }
+
+  if( ( toindex = open( argv[1], O_RDONLY ) ) < 0 )
+    { fprintf( stderr, "Can't open file: %s.\n", argv[1] ); exit( toindex ); }
+
+  fstat( toindex, &fstatus );
+
+  printf( "Size of file: %d\n", fstatus.st_size );
+
+  if( ( mappedfile = mmap( NULL, (size_t)fstatus.st_size, PROT_READ | PROT_WRITE, MAP_NOCORE | MAP_PRIVATE, toindex, 0) ) == MAP_FAILED )
+    { fprintf( stderr, "Can't mmap file: %s.", argv[1] ); exit( 1 ); }
+
+  while( run )
+  {
+    while( ( offset < fstatus.st_size ) && (
+           ( mappedfile[ offset + 0 ] != 0xd9 ) ||
+           ( mappedfile[ offset + 2 ] != 0x6f ) ||
+           ( mappedfile[ offset + 3 ] != 0x6d ) ||
+           ( mappedfile[ offset + 4 ] != 0xaa ) ||
+           ( mappedfile[ offset + 5 ] != 0x11 ) ||
+           ( mappedfile[ offset + 6 ] != 0x6f )
+          ) ) offset++;
+
+    printf( "Found an appropriate offset at: %d\n", oldoffset );
+
+    if( offset == fstatus.st_size )
+      run = 0;
+
+    if( oldoffset != -1 )
+    {
+        unsigned long *mf = (unsigned long*)(mappedfile + oldoffset);
+        unsigned char filename[20], cs = 0;
+
+        for( i=0; i<8; ++i)
+          mf[i]^=0x014224c2;
+
+        snprintf( filename, sizeof( filename ), "%05d.lha", filenum++ );
+
+        memcpy( ((unsigned char*)mf) + 22, filename, 5);
+
+        for( i=2; i<29; ++i)
+          cs += ((unsigned char*)mf)[i];
+        ((unsigned char*)mf)[1] = cs;
+
+        i = open( filename, O_CREAT | O_TRUNC | O_WRONLY, 0644 );
+        write( i, mf, offset - oldoffset );
+        close( i );
+    }
+    oldoffset = offset;
+    offset++;
+  }
+
+  return 0;
+}