experimental dynamic linker!

some notes:
- library search path is hard coded
- x86_64 code is untested and may not work
- dlopen/dlsym is not yet implemented
- relocations in read-only memory won't work

2 files changed, 54 insertions, 0 deletions

diff --git a/arch/i386/reloc.h b/arch/i386/reloc.h
new file mode 100644
index 00000000..02b5fa02
--- /dev/null
+++ b/arch/i386/reloc.h
@@ -0,0 +1,26 @@
+#include <string.h>
+#include <elf.h>
+
+#define IS_COPY(x) ((x)==R_386_COPY)
+
+static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, size_t sym_size, unsigned char *base_addr, size_t addend)
+{
+	switch(type) {
+	case R_386_32:
+		*reloc_addr += sym_val;
+		break;
+	case R_386_PC32:
+		*reloc_addr += sym_val - (size_t)reloc_addr;
+		break;
+	case R_386_GLOB_DAT:
+	case R_386_JMP_SLOT:
+		*reloc_addr = sym_val;
+		break;
+	case R_386_RELATIVE:
+		*reloc_addr += (size_t)base_addr;
+		break;
+	case R_386_COPY:
+		memcpy(reloc_addr, (void *)sym_val, sym_size);
+		break;
+	}
+}
diff --git a/arch/x86_64/reloc.h b/arch/x86_64/reloc.h
new file mode 100644
index 00000000..2db6115d
--- /dev/null
+++ b/arch/x86_64/reloc.h
@@ -0,0 +1,28 @@
+#include <stdint.h>
+#include <string.h>
+#include <elf.h>
+
+#define IS_COPY(x) ((x)==R_X86_64_COPY)
+
+static inline void do_single_reloc(size_t *reloc_addr, int type, size_t sym_val, size_t sym_size, unsigned char *base_addr, size_t addend)
+{
+	switch(type) {
+	case R_X86_64_GLOB_DAT:
+	case R_X86_64_JUMP_SLOT:
+	case R_X86_64_64:
+		*reloc_addr = sym_val + addend;
+		break;
+	case R_X86_64_32:
+		*(uint32_t *)reloc_addr = sym_val + addend;
+		break;
+	case R_X86_64_PC32:
+		*reloc_addr = sym_val + addend - (size_t)reloc_addr + (size_t)base_addr;
+		break;
+	case R_X86_64_RELATIVE:
+		*reloc_addr = (size_t)base_addr + addend;
+		break;
+	case R_X86_64_COPY:
+		memcpy(reloc_addr, (void *)sym_val, sym_size);
+		break;
+	}
+}