[PATCH 1/4] util/grub-module-verifierXX.c: Add function to calculate section headers

[Alec Brown]

Added the function get_shdr() which returns the section header at a given index
parameter passed into this function. This helps traverse the section header
table and reduces repeated calls to lengthy equations used to obtain section
headers.

Note that it may look as though the argument *arch isn't being used, it's
actually required in order to use the macros grub_target_to_host*(x) which are
unwinded to grub_target_to_host*_real(arch, (x)) based on defines earlier in the
file.

Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
---
 util/grub-module-verifierXX.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/util/grub-module-verifierXX.c b/util/grub-module-verifierXX.c
index ceb24309a..92f9ae2a4 100644
--- a/util/grub-module-verifierXX.c
+++ b/util/grub-module-verifierXX.c
@@ -131,6 +131,12 @@ grub_target_to_host_real (const struct 
grub_module_verifier_arch *arch, grub_uin
     return grub_target_to_host32_real (arch, in);
 }
 
+static Elf_Shdr *
+get_shdr (const struct grub_module_verifier_arch *arch, Elf_Ehdr *e, Elf_Word 
index)
+{
+  return (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff) +
+                      index * grub_target_to_host16 (e->e_shentsize));
+}
 
 static Elf_Shdr *
 find_section (const struct grub_module_verifier_arch *arch, Elf_Ehdr *e, const 
char *name)
@@ -139,12 +145,12 @@ find_section (const struct grub_module_verifier_arch 
*arch, Elf_Ehdr *e, const c
   const char *str;
   unsigned i;
 
-  s = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff) + 
grub_target_to_host16 (e->e_shstrndx) * grub_target_to_host16 (e->e_shentsize));
+  s = get_shdr (arch, e, grub_target_to_host16 (e->e_shstrndx));
   str = (char *) e + grub_target_to_host (s->sh_offset);
 
-  for (i = 0, s = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff));
+  for (i = 0, s = get_shdr (arch, e, 0);
        i < grub_target_to_host16 (e->e_shnum);
-       i++, s = (Elf_Shdr *) ((char *) s + grub_target_to_host16 
(e->e_shentsize)))
+       i++, s = get_shdr (arch, e, i))
     if (strcmp (str + grub_target_to_host32 (s->sh_name), name) == 0)
       return s;
   return NULL;
@@ -166,13 +172,12 @@ static Elf_Sym *
 get_symtab (const struct grub_module_verifier_arch *arch, Elf_Ehdr *e, 
Elf_Word *size, Elf_Word *entsize)
 {
   unsigned i;
-  Elf_Shdr *s, *sections;
+  Elf_Shdr *s;
   Elf_Sym *sym;
 
-  sections = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff));
-  for (i = 0, s = sections;
+  for (i = 0, s = get_shdr (arch, e, 0);
        i < grub_target_to_host16 (e->e_shnum);
-       i++, s = (Elf_Shdr *) ((char *) s + grub_target_to_host16 
(e->e_shentsize)))
+       i++, s = get_shdr (arch, e, i))
     if (grub_target_to_host32 (s->sh_type) == SHT_SYMTAB)
       break;
 
@@ -364,9 +369,9 @@ check_relocations (const char * const modname,
   Elf_Shdr *s;
   unsigned i;
 
-  for (i = 0, s = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff));
+  for (i = 0, s = get_shdr (arch, e, 0);
        i < grub_target_to_host16 (e->e_shnum);
-       i++, s = (Elf_Shdr *) ((char *) s + grub_target_to_host16 
(e->e_shentsize)))
+       i++, s = get_shdr (arch, e, i))
     if (grub_target_to_host32 (s->sh_type) == SHT_REL || grub_target_to_host32 
(s->sh_type) == SHT_RELA)
       {
        Elf_Shdr *ts;
@@ -379,7 +384,7 @@ check_relocations (const char * const modname,
        /* Find the target segment.  */
        if (grub_target_to_host32 (s->sh_info) >= grub_target_to_host16 
(e->e_shnum))
          grub_util_error ("%s: orphaned reloc section", modname);
-       ts = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff) + 
grub_target_to_host32 (s->sh_info) * grub_target_to_host16 (e->e_shentsize));
+       ts = get_shdr (arch, e, grub_target_to_host32 (s->sh_info));
 
        section_check_relocations (modname, arch, e, s, grub_target_to_host 
(ts->sh_size));
       }
-- 
2.27.0