From 21b484f6446fc1fc17a3aa7d5777c56fe1b8dd22 Mon Sep 17 00:00:00 2001
From: Thomas Schmitt <scdbackup@gmx.net>
Date: Wed, 16 Jun 2010 14:03:46 +0000
Subject: [PATCH] Made patch_lba0= more modest with overwriting.

---
 xorriso/write_run.c         | 45 ++++++++++++++++++++-----------------
 xorriso/xorriso_timestamp.h |  2 +-
 2 files changed, 26 insertions(+), 21 deletions(-)

diff --git a/xorriso/write_run.c b/xorriso/write_run.c
index 542878e2..dcd6cac3 100644
--- a/xorriso/write_run.c
+++ b/xorriso/write_run.c
@@ -1988,7 +1988,7 @@ int Xorriso_update_iso_lba0(struct XorrisO *xorriso, int iso_lba, int isosize,
  char *headpt;
  struct burn_drive_info *dinfo;
  struct burn_drive *drive;
- off_t seek_ret;
+ off_t seek_ret, to_write;
  int tag_type;
  uint32_t pos, range_start, range_size, next_tag;
  char md5[16];
@@ -2069,28 +2069,32 @@ int Xorriso_update_iso_lba0(struct XorrisO *xorriso, int iso_lba, int isosize,
    headpt[87-i]= headpt[80+i]= (full_size >> (8*i)) & 0xff;
 
 
- /* Invalidate eventual libisofs checksum tags */
- /* Look for volume descriptor end */
- for(i= 16; i < 32; i++)
-   if(((unsigned char *) head_buffer)[i * 2048] == 0xff &&
-      strncmp(head_buffer + i * 2048 + 1, "CD001", 5) == 0)
- break;
- /* Check whether the next one is a libisofs checksum tag */
- if(i < 32) {
-   i++;
-   ret= iso_util_decode_md5_tag(head_buffer + i * 2048, &tag_type, &pos,
-                                &range_start, &range_size, &next_tag, md5, 0);
-   if(ret != 0) /* corrupted or not: invalidate */
-     memset(head_buffer + i * 2048, 0, 8);
- }
-
  if(job != NULL) {
+   /* This is a check_media superblock relocation:
+      Invalidate eventual libisofs checksum tags.
+      Write only up to PVD end plus eventual invalidated tag.
+   */
+   /* Look for volume descriptor end */
+   for(i= 16; i < 32; i++)
+     if(((unsigned char *) head_buffer)[i * 2048] == 0xff &&
+        strncmp(head_buffer + i * 2048 + 1, "CD001", 5) == 0)
+   break;
+   /* Check whether the next one is a libisofs checksum tag */
+   if(i < 32) {
+     i++;
+     ret= iso_util_decode_md5_tag(head_buffer + i * 2048, &tag_type, &pos,
+                                &range_start, &range_size, &next_tag, md5, 0);
+     if(ret != 0) /* corrupted or not: invalidate */
+       memset(head_buffer + i * 2048, 0, 8);
+   }
+   to_write= 2048 * (i + 1);
+
    seek_ret= lseek(job->data_to_fd, (off_t) 0, SEEK_SET);
    if(seek_ret == -1)
      ret= 0;
    else
-     ret= write(job->data_to_fd, head_buffer, 64 * 1024); 
-   if(ret < 64 * 1024) {
+     ret= write(job->data_to_fd, head_buffer, to_write); 
+   if(ret < to_write) {
      Xorriso_process_msg_queues(xorriso,0);
      sprintf(xorriso->info_text,
              "Cannot write ISO image head to file copy"); 
@@ -2098,8 +2102,9 @@ int Xorriso_update_iso_lba0(struct XorrisO *xorriso, int iso_lba, int isosize,
      return(0);
    }
  } else {
-   ret= burn_random_access_write(drive, (off_t) 0, head_buffer,
-                                 (off_t) (64*1024), 1);
+   /* This is a regular superblock relocation. Write full 64 kB. */
+   to_write= 64 * 1024;
+   ret= burn_random_access_write(drive, (off_t) 0, head_buffer, to_write, 1);
    if(ret<=0) {
      Xorriso_process_msg_queues(xorriso,0);
      sprintf(xorriso->info_text,
diff --git a/xorriso/xorriso_timestamp.h b/xorriso/xorriso_timestamp.h
index 7aeadf51..e8da59c7 100644
--- a/xorriso/xorriso_timestamp.h
+++ b/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2010.06.16.105652"
+#define Xorriso_timestamP "2010.06.16.140253"