ld: resolve: fix incorrect symbol and GOT index calculation

sys/ld/resolve.c

@@ -6,17 +6,42 @@
 
 uintptr_t dl_runtime_resolve(struct elf_image *img, unsigned long sym_id)
 {
+	unsigned long slot_id = sym_id;
+	switch (img->e_rel_entsize[ELF_RT_PLTREL]) {
+	case sizeof(elf_rela_t): {
+		elf_rela_t *rela
+			= (elf_rela_t *)((virt_addr_t)img->e_base
+		                         + img->e_rel_offset[ELF_RT_PLTREL]);
+		elf_rela_t *rela_sym = &rela[sym_id];
+		kern_tracef(
+			"rela %u -> .dynsym %u, .got %u",
+			sym_id,
+			ELF64_R_SYM(rela_sym->r_info),
+			slot_id);
+		sym_id = ELF64_R_SYM(rela_sym->r_info);
+		/* the first three entries in the GOT are not symbols. */
+		slot_id += 3;
+		break;
+	}
+
+	default:
+		return 0;
+	}
+
 	elf_sym_t *sym
 		= (elf_sym_t *)((virt_addr_t)img->e_base + img->e_dynsym);
+	virt_addr_t *got
+		= (virt_addr_t *)((virt_addr_t)img->e_base + img->e_got_plt);
 	const char *sym_name = (const char *)img->e_base + img->e_strtab
-	                     + sym[sym_id + 1].st_name;
+	                     + sym[sym_id].st_name;
-	// kern_logf("%s: request for symbol %s", img->e_leaf.l_name, sym_name);
+	kern_tracef(
+		"%s: request for symbol %u: %s",
+		img->e_leaf.l_name,
+		sym_id,
+		sym_name);
 	virt_addr_t sym_addr = elf_image_find_linked_symbol(img, sym_name);
-	virt_addr_t *sym_slot
+	kern_tracef("symbol %s = %zx", sym_name, sym_addr);
-		= (virt_addr_t *)((virt_addr_t)img->e_base + img->e_got_plt
+	kern_tracef("slot %s = %zx", sym_name, &got[slot_id]);
-	                          + ((sym_id + 3) * sizeof(virt_addr_t)));
+	got[slot_id] = sym_addr;
-	// kern_logf("symbol %s = %zx", sym_name, sym_addr);
-	// kern_logf("slot %s = %zx", sym_name, sym_slot);
-	*sym_slot = sym_addr;
 	return sym_addr;
 }