limit Seek() to file size or return error

cnvogelg · Feb 2, 2025 · 0b0c60d · 0b0c60d
1 parent 108e486
commit 0b0c60d
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Showing 2 changed files with 26 additions and 5 deletions.
diff --git a/amitools/vamos/lib/DosLibrary.py b/amitools/vamos/lib/DosLibrary.py
@@ -756,12 +756,20 @@ def Seek(self, ctx, fh_b_addr, pos, mode):
 
         old_pos = fh.tell()
         new_pos = fh.seek(pos, whence)
-        log_dos.info("Seek(%s, %06x, %s) -> old_pos=%06x", fh, pos, mode_str, old_pos)
-        if new_pos == -1:
+        log_dos.info(
+            "Seek(%s, %d, %s) -> old_pos=%d new_pos=%d",
+            fh,
+            pos,
+            mode_str,
+            old_pos,
+            new_pos,
+        )
+        if new_pos < 0:
             self.setioerr(ctx, ERROR_SEEK_ERROR)
+            return -1
         else:
             self.setioerr(ctx, 0)
-        return old_pos
+            return old_pos
 
     def FGetC(self, ctx, fh_b_addr):
         fh = self.file_mgr.get_by_b_addr(fh_b_addr, False)

diff --git a/amitools/vamos/lib/dos/FileHandle.py b/amitools/vamos/lib/dos/FileHandle.py
@@ -183,10 +183,23 @@ def tell(self):
     def seek(self, pos, whence):
         """set to position from whence
 
-        return -1 on error or new_pos
+        return -1 on error, -2 on too far or new_pos
         """
         try:
-            return self.obj.seek(pos, whence)
+            new_pos = self.obj.seek(pos, whence)
+
+            # we have to limit seek to file size
+            stat = os.stat(self.obj.fileno())
+            file_size = stat.st_size
+
+            # if seek to far then limit to file size
+            if new_pos > file_size:
+                # seek to end
+                self.obj.seek(file_size, 0)
+                return -2
+
+            return new_pos
+
         except IOError:
             return -1