[PATCH v4 10/17] dump: Swap segment and section header locations

[Janosch Frank]

For the upcoming string table and arch section support we need to
modify the elf layout a bit. Instead of the segments, i.e. the guest's
memory contents, beeing the last area the section data will live at
the end of the file. This will allow us to write the section data
after all guest memory has been dumped which is important for the s390
PV dump support.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
 dump/dump.c           | 21 ++++++++++++---------
 include/sysemu/dump.h |  1 +
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/dump/dump.c b/dump/dump.c
index a6bb7bfa21..3cf846d0a0 100644
--- a/dump/dump.c
+++ b/dump/dump.c
@@ -588,6 +588,9 @@ static void dump_begin(DumpState *s, Error **errp)
      *   --------------
      *   |  memory     |
      *   --------------
+     *   |  sectn data |
+     *   --------------
+
      *
      * we only know where the memory is saved after we write elf note into
      * vmcore.
@@ -1852,18 +1855,18 @@ static void dump_init(DumpState *s, int fd, bool 
has_format,
         }
     }
 
+    tmp = (s->phdr_num == PN_XNUM) ? s->sh_info : s->phdr_num;
     if (dump_is_64bit(s)) {
-        s->phdr_offset = sizeof(Elf64_Ehdr);
-        s->shdr_offset = s->phdr_offset + sizeof(Elf64_Phdr) * s->phdr_num;
-        s->note_offset = s->shdr_offset + sizeof(Elf64_Shdr) * s->shdr_num;
-        s->memory_offset = s->note_offset + s->note_size;
+        s->shdr_offset = sizeof(Elf64_Ehdr);
+        s->phdr_offset = s->shdr_offset + sizeof(Elf64_Shdr) * s->shdr_num;
+        s->note_offset = s->phdr_offset + sizeof(Elf64_Phdr) * tmp;
     } else {
-
-        s->phdr_offset = sizeof(Elf32_Ehdr);
-        s->shdr_offset = s->phdr_offset + sizeof(Elf32_Phdr) * s->phdr_num;
-        s->note_offset = s->shdr_offset + sizeof(Elf32_Shdr) * s->shdr_num;
-        s->memory_offset = s->note_offset + s->note_size;
+        s->shdr_offset = sizeof(Elf32_Ehdr);
+        s->phdr_offset = s->shdr_offset + sizeof(Elf32_Shdr) * s->shdr_num;
+        s->note_offset = s->phdr_offset + sizeof(Elf32_Phdr) * tmp;
     }
+    s->memory_offset = s->note_offset + s->note_size;
+    s->section_offset = s->memory_offset + s->total_size;
 
     return;
 
diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h
index 3937afe0f9..696e6c67d6 100644
--- a/include/sysemu/dump.h
+++ b/include/sysemu/dump.h
@@ -172,6 +172,7 @@ typedef struct DumpState {
     hwaddr shdr_offset;
     hwaddr phdr_offset;
     hwaddr note_offset;
+    hwaddr section_offset;
 
     void *elf_header;
     void *elf_section_hdrs;
-- 
2.34.1