From 571f43ec01f49a9630b10c4c3c8a224f0aeb01ee Mon Sep 17 00:00:00 2001
From: patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>
Date: Wed, 24 Oct 2012 23:40:31 +0000
Subject: A little more ELF loader logic

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5253 42af7a65-404d-4744-a932-0658087f49c3
---
 nuttx/binfmt/libelf/libelf_verify.c | 42 ++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

(limited to 'nuttx/binfmt/libelf/libelf_verify.c')

diff --git a/nuttx/binfmt/libelf/libelf_verify.c b/nuttx/binfmt/libelf/libelf_verify.c
index 9139700b3..0e0dd8e1a 100644
--- a/nuttx/binfmt/libelf/libelf_verify.c
+++ b/nuttx/binfmt/libelf/libelf_verify.c
@@ -42,7 +42,7 @@
 #include <string.h>
 #include <debug.h>
 #include <errno.h>
-#include <arpa/inet.h>
+
 #include <nuttx/binfmt/elf.h>
 
 /****************************************************************************
@@ -53,6 +53,8 @@
  * Private Constant Data
  ****************************************************************************/
 
+static const char g_elfmagic[EI_MAGIC_SIZE] = { 0x7f, 'E', 'L', 'F' }
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -72,17 +74,47 @@
  *   0 (OK) is returned on success and a negated errno is returned on
  *   failure.
  *
+ *   -ENOEXEC  : Not an ELF file
+ *   -EINVALID : Not a relocatable ELF file or not supported by the current,
+ *               configured architecture.
+ *
  ****************************************************************************/
 
-int elf_verifyheader(const Elf32_Ehdr *header)
+int elf_verifyheader(const Elf32_Ehdr *ehdr)
 {
-  if (!header)
+  if (!ehdr)
     {
       bdbg("NULL ELF header!");
       return -ENOEXEC;
     }
 
-#warning "Missing Logic"
-  return -ENOSYS;
+  /* Verify that the magic number indicates an ELF file */
+
+  if (memcmp(ehdr->e_ident, g_elfmagic, EI_MAGIC_SIZE) != 0)
+    {
+      bvdbg("Not ELF magic {%02x, %02x, %02x, %02x}\n",
+            ehdr->e_ident[0], ehdr->e_ident[1], ehdr->e_ident[2], ehdr->e_ident[3]);
+      return -ENOEXEC;
+    }
+
+  /* Verify that this is a relocatable file */
+
+  if (ehdr->e_type != ET_REL)
+    {
+      bdbg("Not a relocatable file: e_type=%d\n", ehdr->e_type);
+      return -EINVALID;
+    }
+
+  /* Verify that this file works with the currently configured architecture */
+
+  if (arch_checkarch(ehdr))
+    {
+      bdbg("Not a supported architecture\n");
+      return -ENOEXEC;
+    }
+
+  /* Looks good so far... we still might find some problems later. */
+
+  return OK;
 }
 
-- 
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