1 files changed, 70 insertions, 0 deletions
diff --git a/src/libelfu/modelops/relocate.c b/src/libelfu/modelops/relocate.c
new file mode 100644
index 0000000..eefed02
--- /dev/null
+++ b/src/libelfu/modelops/relocate.c
@@ -0,0 +1,70 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libelfu/libelfu.h>
+
+
+/* Apply relocation information from section *msrt to data in
+ * section *mstarget (which is stored in *metarget). */
+void elfu_mRelocate(ElfuElf *metarget, ElfuScn *mstarget, ElfuScn *msrt)
+{
+  ElfuRel *rel;
+
+  assert(mstarget);
+  assert(msrt);
+
+  ELFU_DEBUG("Relocating in section of type %u size %x\n",
+             mstarget->shdr.sh_type,
+             (unsigned)mstarget->shdr.sh_size);
+
+  CIRCLEQ_FOREACH(rel, &msrt->reltab.rels, elem) {
+    Elf32_Word *dest32 = (Elf32_Word*)(((char*)(mstarget->data.d_buf)) + rel->offset);
+    Elf64_Word *dest64 = (Elf64_Word*)(((char*)(mstarget->data.d_buf)) + rel->offset);
+
+
+    if (metarget->elfclass == ELFCLASS32) {
+      Elf32_Word a32 = rel->addendUsed ? rel->addend : *dest32;
+      Elf32_Addr p32 = mstarget->shdr.sh_addr + rel->offset;
+      Elf32_Addr s32 = elfu_mSymtabLookupVal(metarget, msrt->linkptr, rel->sym);
+      switch(rel->type) {
+        case R_386_NONE:
+          ELFU_DEBUG("Skipping relocation: R_386_NONE\n");
+          break;
+        case R_386_32:
+          *dest32 = s32 + a32;
+          break;
+        case R_386_PC32:
+          *dest32 = s32 + a32 - p32;
+          break;
+
+        default:
+          ELFU_DEBUG("Skipping relocation: Unknown type %d\n", rel->type);
+      }
+    } else if (metarget->elfclass == ELFCLASS64) {
+      Elf64_Word a64 = rel->addend;
+      Elf64_Addr p64 = mstarget->shdr.sh_addr + rel->offset;
+      Elf64_Addr s64 = elfu_mSymtabLookupVal(metarget, msrt->linkptr, rel->sym);
+
+      /* x86-64 only uses RELA with explicit addend. */
+      assert(rel->addendUsed);
+
+      switch(rel->type) {
+        case R_X86_64_NONE:
+          ELFU_DEBUG("Skipping relocation: R_386_NONE\n");
+          break;
+        case R_X86_64_64:
+          *dest64 = s64 + a64;
+          break;
+        case R_X86_64_PC32:
+          *dest32 = s64 + a64 - p64;
+          break;
+        case R_X86_64_32:
+          *dest32 = s64 + a64;
+          break;
+
+        default:
+          ELFU_DEBUG("Skipping relocation: Unknown type %d", rel->type);
+      }
+    }
+  }
+}