New bit15 with options of iso_write_opts_set_system_area() to enforce

MBR bootable/active flag.

libisofs/ecma119.c

@@ -3990,7 +3990,7 @@ int iso_write_opts_set_system_area(IsoWriteOpts *opts, char data[32768],
         opts->system_area_size = 32768;
     }
     if (!(flag & 4))
-        opts->system_area_options = options & 0x7fff;
+        opts->system_area_options = options & 0xffff;
     return ISO_SUCCESS;
 }
 

libisofs/fs_image.c

@@ -3940,6 +3940,7 @@ int iso_analyze_mbr(IsoImage *image, IsoDataSource *src, int flag)
 {
     int sub_type = 2, ret, is_isohybrid = 0, is_grub2_mbr = 0;
     int is_protective_label = 0;
+    uint64_t part2_start;
     char *sad;
     struct iso_imported_sys_area *sai;
     struct iso_mbr_partition_request *part;
@@ -3969,8 +3970,12 @@ int iso_analyze_mbr(IsoImage *image, IsoDataSource *src, int flag)
 
     if (sai->mbr_req_count >= 1 && !is_isohybrid) {
         part = sai->mbr_req[0];
+        part2_start = 0;
+        if (sai->mbr_req_count >= 2)
+            part2_start = sai->mbr_req[1]->start_block;
         if (part->start_block == 1 &&
-            part->block_count + 1 == ((uint64_t) sai->image_size) * 4) {
+            (part->block_count + 1 == ((uint64_t) sai->image_size) * 4 ||
+             part->block_count + 1 == part2_start)) {
             /* libisofs protective msdos label for GRUB2 */
             is_protective_label = 1;
             sub_type = 0;

libisofs/libisofs.h

@@ -2215,8 +2215,9 @@ int iso_write_opts_set_fifo_size(IsoWriteOpts *opts, size_t fifo_size);
  *                    @since 1.2.6
  *        bit10-13= System area sub type
  *              @since 1.2.4
- *              With type 0 = MBR:
+ *              With type 0:
- *                Gets overridden by bit0 and bit1.
+ *                bit0 ... MBR with partition start at block 1
+ *                bit1 ... ISOLINUX isohybrid MBR
  *                0 = no particular sub type, use unaltered
  *                1 = CHRP: A single MBR partition of type 0x96 covers the
  *                          ISO image. Not compatible with any other feature
@@ -2228,8 +2229,12 @@ int iso_write_opts_set_fifo_size(IsoWriteOpts *opts, size_t fifo_size);
  *              Patch system area at byte 0x1b0 to 0x1b7 with
  *              (512-block address + 4)  of the first boot image file.
  *              Little-endian 8-byte.
- *              Should be combined with options bit0.
+ *              Is normally combined with options bit0.
  *              Will not be in effect if options bit1 is set.
+ *        bit15= Only with System area type MBR but not with CHRP
+ *              Enforce MBR "bootable/active" flag. In worst case by dummy
+ *              partition of type 0x00 which occupies block 0.
+ *              @since 1.4.4
  * @param flag
  *        bit0 = invalidate any attached system area data. Same as data == NULL
  *               (This re-activates eventually loaded image System Area data.
@@ -3403,7 +3408,7 @@ int iso_image_get_pvd_times(IsoImage *image,
  * @param image_path
  *      The absolute path of a IsoFile to be used as default boot image.
 
->>> or  --interval:appended_partition_$number...
+>>> or  --interval:appended_partition_$number_start_$start_size_$size:...
 
  * @param type
  *      The boot media type. This can be one of 3 types:

libisofs/system_area.c

@@ -1749,38 +1749,33 @@ static int iso_write_gpt(Ecma119Image *t, uint32_t img_blocks, uint8_t *buf)
 }
 
 
-#ifdef Libisofs_protective_msdos_plus_boot_dummY
+/* Add a dummy MBR partition of type 0 with boot flag */
-
 static void iso_dummy_mbr_partition(uint8_t *buf, int mode)
 {
-    /* Add a dummy partition of type 0 with boot flag */
+    int i;
-    if (mode == 0) {
+                             /* bootable , start 0/0/1, type 0x00, end 0/0/1,
-        /* Start LBA 0, block count 1 */
+                                start LBA 0, block count 1 */
-        buf[446 + 16 +  0] = 0x80;  /* bootable */
+    static uint8_t dummy_entry[16] = {
-        buf[446 + 16 +  1] = 0x00;  /* start head */
+                              0x80, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x00,
-        buf[446 + 16 +  2] = 0x01;  /* start sector */
+                              0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00 };
-        buf[446 + 16 +  3] = 0x00;  /* start cylinder */
+
-        buf[446 + 16 +  4] = 0x00;  /* partition type */
+    for (i = 0; i < 4; i++) {
-        buf[446 + 16 +  5] = 0x00;  /* end head */
+        if (buf[446 + 16 * i + 4] == 0x00) {
-        buf[446 + 16 +  6] = 0x01;  /* last sector */
+            memcpy(buf + 446 + 16 * i, dummy_entry, 16);
-        buf[446 + 16 +  7] = 0x00;  /* end cylinder */
+            return;
-        buf[446 + 16 +  8] = 0x00;  /* start LBA */
-        buf[446 + 16 +  9] = 0x00;
-        buf[446 + 16 + 10] = 0x00;
-        buf[446 + 16 + 11] = 0x00;
-        buf[446 + 16 + 12] = 0x01;  /* block count */
-        buf[446 + 16 + 13] = 0x00;
-        buf[446 + 16 + 14] = 0x00;
-        buf[446 + 16 + 15] = 0x00;
-    } else {
-        /* copy partition 1 to 2, set boot flag and type 0x00 */
-        memcpy(buf + 446 + 16, buf + 446, 16);
-        buf[446 + 16 +  0] = 0x80;  /* bootable */
-        buf[446 + 16 +  4] = 0x00;  /* partition type */
         }
     }
+    /* Abundance of 0xee and 0xef partitions. No other one free. */
+    for (i = 0; i < 4; i++) {
+        if (buf[446 + 16 * i + 4] != 0xef) {
+            buf[446 + 16 * i] |= 0x80;
+            return;
+        }
+    }
+    i = 3;
+    buf[446 + 16 * i] |= 0x80;
+}
 
-#endif /* Libisofs_protective_msdos_plus_boot_dummY */
 
 int iso_write_system_area(Ecma119Image *t, uint8_t *buf)
 {
@@ -2077,24 +2072,6 @@ int iso_write_system_area(Ecma119Image *t, uint8_t *buf)
 
 #ifdef Libisofs_mjg_boot_for_grub2
 
-
-    if (buf[446 + 4] != 0x00) {
-        if (buf[446 + 4] != 0xef && buf[446 + 4] != 0xee)
-            buf[446] |= 0x80;
-
-#ifdef Libisofs_protective_msdos_plus_boot_dummY
-
-        else if (buf[446 + 16 + 4] == 0x00 && (buf[446 + 16] & 0x80) == 0)
-#ifdef Libisofs_pmpbd_on_lba0
-            iso_dummy_mbr_partition(buf, 0);
-#else
-            iso_dummy_mbr_partition(buf, 1);
-#endif /* ! Libisofs_pmpbd_on_lba0 */
-
-#endif
-
-    }
-
     /* Prevent MBR partition type 0xee */
     if (sa_type == 0 && ((t->system_area_options & 3) || risk_of_ee) &&
         (t->have_appended_partitions || t->gpt_req_count == 0)) {
@@ -2120,26 +2097,33 @@ int iso_write_system_area(Ecma119Image *t, uint8_t *buf)
         }
     }
 
-#ifdef Libisofs_protective_msdos_plus_boot_dummY
+    if (sa_type == 0 && (
-
+        (t->system_area_options & 3) ||
-    if (sa_type == 0 && (t->system_area_options & 3) == 1 &&
+        (t->system_area_options & (1 << 14)) ||
-        buf[446 + 4] == 0xee && buf[446] == 0x00) {
+        (((t->system_area_options >> 2) & 0x3f) == 2 &&
-        for (i = 446 + 16 ; i < 510; i++)
+         (t->system_area_options & (1 << 15)))
-            if(buf[i])
+        )) {
+        /* This is an MBR which shall have a bootable/active flag
+           protective-msdos-label, isohybrid, grub2-mbr, mbr-force-bootable
+         */
+        for (i = 0; i < 4; i++)
+            if (buf[446 + 16 * i] & 0x80)
         break;
-        if (i >= 510) {
+        if (i >= 4) { /* no bootable/active flag set yet */
-            /* Add a dummy partition of type 0 with boot flag */
+            for (i = 0; i < 4; i++) {
-
+                if (buf[446 + 16 * i + 4] != 0x00 &&
-#ifdef Libisofs_pmpbd_on_lba0
+                    buf[446 + 16 * i + 4] != 0xee &&
+                    buf[446 + 16 * i + 4] != 0xef) {
+                    buf[446 + 16 * i] |= 0x80;
+            break;
+                }
+            }
+            if (i >= 4) { /* still no bootable/active flag set */
+                if (t->system_area_options & (1 << 15)) /* Force it */
                     iso_dummy_mbr_partition(buf, 0);
-#else
-            iso_dummy_mbr_partition(buf, 1);
-#endif /* ! Libisofs_pmpbd_on_lba0 */
-
             }
         }
-
+    }
-#endif /* Libisofs_protective_msdos_plus_boot_dummY */
 
     return ISO_SUCCESS;
 }