chain.c32: correctly set the length of the GPT handover structure

We need to make sure the entire GPT handover structure is mapped
correctly by the shuffler.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

diff --git a/com32/modules/chain.c b/com32/modules/chain.c
index 6f3729f..b4fe3ef 100644 (file)
--- a/com32/modules/chain.c
+++ b/com32/modules/chain.c
@@ -1419,60 +1419,67 @@ int main(int argc, char *argv[])
        ndata++;
     }
 
-    /* Do GPT hand-over, if applicable (as per syslinux/doc/gpt.txt) */
-    if (cur_part && (cur_part->next == next_gpt_part)) {
-       struct part_entry *record;
-       /* Look at the GPT partition */
-       const struct gpt_part *gp = (const struct gpt_part *)
+    if (cur_part) {
+       if (cur_part->next == next_gpt_part) {
+           /* Do GPT hand-over, if applicable (as per syslinux/doc/gpt.txt) */
+           struct part_entry *record;
+           /* Look at the GPT partition */
+           const struct gpt_part *gp = (const struct gpt_part *)
            (cur_part->block +
             (cur_part->private.gpt.size * cur_part->private.gpt.index));
-       /* Note the partition length */
-       uint64_t lba_count = gp->lba_last - gp->lba_first + 1;
-       /* The length of the hand-over */
-       int synth_size =
-           sizeof(struct part_entry) + sizeof(uint32_t) +
-           cur_part->private.gpt.size;
-       /* Will point to the partition record length in the hand-over */
-       uint32_t *plen;
-
-       /* Allocate the hand-over record */
-       record = malloc(synth_size);
-       if (!record) {
-           error("Could not build GPT hand-over record!\n");
-           goto bail;
-       }
-       /* Synthesize the record */
-       memset(record, 0, synth_size);
-       record->active_flag = 0x80;
-       record->ostype = 0xED;
-       /* All bits set by default */
-       record->start_lba = ~(uint32_t) 0;
-       record->length = ~(uint32_t) 0;
-       /* If these fit the precision, pass them on */
-       if (cur_part->lba_data < record->start_lba)
-           record->start_lba = cur_part->lba_data;
-       if (lba_count < record->length)
-           record->length = lba_count;
-       /* Next comes the GPT partition record length */
-       plen = (uint32_t *) (record + 1);
-       plen[0] = cur_part->private.gpt.size;
-       /* Next comes the GPT partition record copy */
-       memcpy(plen + 1, gp, plen[0]);
-       cur_part->record = record;
-       regs.eax.l = 0x54504721;        /* '!GPT' */
+           /* Note the partition length */
+           uint64_t lba_count = gp->lba_last - gp->lba_first + 1;
+           /* The length of the hand-over */
+           int synth_size =
+               sizeof(struct part_entry) + sizeof(uint32_t) +
+               cur_part->private.gpt.size;
+           /* Will point to the partition record length in the hand-over */
+           uint32_t *plen;
+
+           /* Allocate the hand-over record */
+           record = malloc(synth_size);
+           if (!record) {
+               error("Could not build GPT hand-over record!\n");
+               goto bail;
+           }
+           /* Synthesize the record */
+           memset(record, 0, synth_size);
+           record->active_flag = 0x80;
+           record->ostype = 0xED;
+           /* All bits set by default */
+           record->start_lba = ~(uint32_t) 0;
+           record->length = ~(uint32_t) 0;
+           /* If these fit the precision, pass them on */
+           if (cur_part->lba_data < record->start_lba)
+               record->start_lba = cur_part->lba_data;
+           if (lba_count < record->length)
+               record->length = lba_count;
+           /* Next comes the GPT partition record length */
+           plen = (uint32_t *) (record + 1);
+           plen[0] = cur_part->private.gpt.size;
+           /* Next comes the GPT partition record copy */
+           memcpy(plen + 1, gp, plen[0]);
+           cur_part->record = record;
+
+           regs.eax.l = 0x54504721;    /* '!GPT' */
+           data[ndata].base = 0x7be;
+           data[ndata].size = synth_size;
+           data[ndata].data = (void *)record;
+           ndata++;
+           regs.esi.w[0] = 0x7be;
 #if DEBUG
-       mbr_part_dump(record);
-       gpt_part_dump((struct gpt_part *)(plen + 1));
+           mbr_part_dump(record);
+           gpt_part_dump((struct gpt_part *)(plen + 1));
 #endif
-    }
-
-    if (cur_part && cur_part->record) {
-       /* 0x7BE is the canonical place for the first partition entry. */
-       data[ndata].data = (void *)cur_part->record;
-       data[ndata].base = 0x7be;
-       data[ndata].size = sizeof(*cur_part->record);
-       ndata++;
-       regs.esi.w[0] = 0x7be;
+       } else if (cur_part->record) {
+           /* MBR handover protocol */
+
+           data[ndata].base = 0x7be;
+           data[ndata].size = sizeof(*cur_part->record);
+           data[ndata].data = (void *)cur_part->record;
+           ndata++;
+           regs.esi.w[0] = 0x7be;
+       }
     }
 
     do_boot(data, ndata, &regs);