Making an educated guess whether the boot images contain a boot info table.

New API call el_torito_seems_boot_info_table() publishes this guess.

libisofs/eltorito.c

@@ -153,8 +153,14 @@ int el_torito_get_selection_crit(ElToritoBootImage *bootimg, uint8_t crit[20])
     return 1;
 }
 
+/* API */
+int el_torito_seems_boot_info_table(ElToritoBootImage *bootimg, int flag)
+{
+    return bootimg->seems_boot_info_table;
+}
+
 /**
- * Specifies that this image needs to be patched. This involves the writting
+ * Specifies that this image needs to be patched. This involves the writing
  * of a 56 bytes boot information table at offset 8 of the boot image file.
  * The original boot image file won't be modified.
  * This is needed for isolinux boot images.
@@ -173,7 +179,7 @@ void el_torito_patch_isolinux_image(ElToritoBootImage *bootimg)
  *        bitmask style flag. The following values are defined:
  *
  *        bit 0 -> 1 to path the image, 0 to not
- *                 Patching the image involves the writting of a 56 bytes
+ *                 Patching the image involves the writing of a 56 bytes
  *                 boot information table at offset 8 of the boot image file.
  *                 The original boot image file won't be modified. This is needed
  *                 to allow isolinux images to be bootable.
@@ -405,6 +411,7 @@ int create_image(IsoImage *image, const char *image_path,
     boot->image = (IsoFile*)imgfile;
     iso_node_ref(imgfile); /* get our ref */
     boot->bootable = 1;
+    boot->seems_boot_info_table = 0;
     boot->isolinux_options = 0;
     boot->type = boot_media_type;
     boot->partition_type = partition_type;
@@ -677,10 +684,12 @@ void el_torito_boot_catalog_free(struct el_torito_boot_catalog *cat)
         image = cat->bootimages[i];
         if (image == NULL)
     continue;
-        iso_node_unref((IsoNode*)image->image);
+        if ((IsoNode*)image->image != NULL)
+            iso_node_unref((IsoNode*)image->image);
         free(image);
     }
-    iso_node_unref((IsoNode*)cat->node);
+    if ((IsoNode*)cat->node != NULL)
+        iso_node_unref((IsoNode*)cat->node);
     free(cat);
 }
 
@@ -981,6 +990,50 @@ int el_torito_catalog_file_src_create(Ecma119Image *target, IsoFileSrc **src)
 
 /******************* EL-TORITO WRITER *******************************/
 
+/**
+ * Insert boot info table content into buf.
+ *
+ * @return
+ *      1 on success, 0 error (but continue), < 0 error
+ */
+int make_boot_info_table(uint8_t *buf, uint32_t pvd_lba,
+                         uint32_t boot_lba, uint32_t imgsize)
+{
+    struct boot_info_table *info;
+    uint32_t checksum;
+    uint32_t offset;
+
+    info = (struct boot_info_table *) (buf + 8);
+    if (imgsize < 64)
+        return ISO_ISOLINUX_CANT_PATCH;
+
+    /* compute checksum, as the the sum of all 32 bit words in boot image
+     * from offset 64 */
+    checksum = 0;
+    offset = 64;
+
+    while (offset <= imgsize - 4) {
+        checksum += iso_read_lsb(buf + offset, 4);
+        offset += 4;
+    }
+    if (offset != imgsize) {
+        /*
+         * file length not multiple of 4
+         * empty space in isofs is padded with zero;
+         * assume same for last dword
+         */
+        checksum += iso_read_lsb(buf + offset, imgsize - offset);
+    }
+
+    /*memset(info, 0, sizeof(struct boot_info_table));*/
+    iso_lsb(info->bi_pvd, pvd_lba, 4);
+    iso_lsb(info->bi_file, boot_lba, 4);
+    iso_lsb(info->bi_length, imgsize, 4);
+    iso_lsb(info->bi_csum, checksum, 4);
+    memset(buf + 24, 0, 40);
+    return ISO_SUCCESS;
+}
+
 /**
  * Patch an isolinux boot image.
  *
@@ -990,6 +1043,24 @@ int el_torito_catalog_file_src_create(Ecma119Image *target, IsoFileSrc **src)
 static
 int patch_boot_image(uint8_t *buf, Ecma119Image *t, size_t imgsize, int idx)
 {
+
+/* >>> ts B00428 BOOT : make this the default case */
+#define Libisofs_new_patch_boot_imagE 1 
+#ifdef Libisofs_new_patch_boot_imagE
+
+    int ret;
+
+    if (imgsize < 64) {
+        return iso_msg_submit(t->image->id, ISO_ISOLINUX_CANT_PATCH, 0,
+            "Isolinux image too small. We won't patch it.");
+    }
+    ret = make_boot_info_table(buf, t->ms_block + (uint32_t) 16,
+                               t->bootsrc[idx]->sections[0].block,
+                               (uint32_t) imgsize);
+    return ret;
+
+#else /* Libisofs_new_patch_boot_imagE */
+
     struct boot_info_table *info;
     uint32_t checksum;
     size_t offset;
@@ -1024,7 +1095,11 @@ int patch_boot_image(uint8_t *buf, Ecma119Image *t, size_t imgsize, int idx)
     iso_lsb(info->bi_file, t->bootsrc[idx]->sections[0].block, 4);
     iso_lsb(info->bi_length, imgsize, 4);
     iso_lsb(info->bi_csum, checksum, 4);
+    memset(buf + 24, 0, 40);
     return ISO_SUCCESS;
+
+#endif /* ! Libisofs_new_patch_boot_imagE */
+
 }
 
 static
@@ -1054,6 +1129,10 @@ int eltorito_writer_compute_data_blocks(IsoImageWriter *writer)
     continue;
         original = t->bootsrc[idx]->stream;
         size = (size_t) iso_stream_get_size(original);
+
+        /* >>> BOOT ts B00428 :
+               check whether size is not too large for buffering */;
+
         buf = calloc(1, size);
         if (buf == NULL) {
             return ISO_OUT_OF_MEM;