Added --shred command line arg to fill free sectors with zero

atrcopy/__init__.py

@@ -174,6 +174,12 @@ def assemble(image, source_files, data_files):
     if changed:
         image.save()
 
+def shred_image(image, value=0):
+    print "shredding: free sectors from %s filled with %d" % (image, value)
+    if not options.dry_run:
+        image.shred()
+        image.save()
+
 
 def run():
     import sys
@@ -199,6 +205,7 @@ def run():
     parser.add_argument("-s", "--asm", nargs="+", action="append", help="source file(s) to assemble using pyatasm (requires -o to specify filename stored on disk image)")
     parser.add_argument("-b", "--bytes", nargs="+", action="append", help="data file(s) to add to assembly, specify as file@addr (requires -o to specify filename stored on disk image)")
     parser.add_argument("-o", "--output", action="store", default="", help="output file name for those commands that need it")
+    parser.add_argument("--shred", action="store_true", default=False, help="fill empty sectors with 0")
     options, extra_args = parser.parse_known_args()
     print options, extra_args
 
@@ -235,3 +242,6 @@ def run():
                 assemble(parser.image, asm, datafiles)
             else:
                 list_files(parser.image, file_list)
+
+            if options.shred:
+                shred_image(parser.image)

atrcopy/diskimages.py

@@ -48,6 +48,13 @@ class BaseHeader(object):
 
     def sector_is_valid(self, sector):
         return (self.max_sectors < 0) | (sector >= self.starting_sector_label and sector < (self.max_sectors + self.starting_sector_label))
+
+    def iter_sectors(self):
+        i = self.starting_sector_label
+        while self.sector_is_valid(i):
+            pos, size = self.get_pos(i)
+            yield i, pos, size
+            i += 1
     
     def get_pos(self, sector):
         """Get index (into the raw data of the disk image) of start of sector
@@ -374,3 +381,17 @@ class DiskImageBase(object):
             raise
         finally:
             self.get_metadata()
+
+    def shred(self, fill_value=0):
+        state = self.begin_transaction()
+        try:
+            vtoc_segments = self.get_vtoc_segments()
+            vtoc = self.vtoc_class(self.header, vtoc_segments)
+            for sector_num, pos, size in vtoc.iter_free_sectors(self.header):
+                log.debug("shredding: sector %s at %d, fill value=%d" % (sector_num, pos, fill_value))
+                self.bytes[pos:pos + size] = fill_value
+        except AtrError:
+            self.rollback_transaction(state)
+            raise
+        finally:
+            self.get_metadata()

atrcopy/utils.py

@@ -248,6 +248,11 @@ class VTOC(BaseSectorList):
         free = np.where(self.sector_map == 1)[0]
         return len(free)
 
+    def iter_free_sectors(self, header):
+        for i, pos, size in header.iter_sectors():
+            if self.sector_map[i] == 1:
+                yield i, pos, size
+
     def parse_segments(self, segments):
         raise NotImplementedError