+
+int
+arch_elf_init(struct ltelf *lte, struct library *lib)
+{
+ VECT_INIT(<e->arch.plt_map, unsigned int);
+
+ /* IRELATIVE slots may make the whole situation a fair deal
+ * more complex. On x86{,_64}, the PLT slots are not
+ * presented in the order of the corresponding relocations,
+ * but in the order it which these symbols are in the symbol
+ * table. That's static symbol table, which may be stripped
+ * off, not dynsym--that doesn't contain IFUNC symbols at all.
+ * So we have to decode each PLT entry to figure out what
+ * entry it corresponds to. We need to interpret the PLT
+ * table to figure this out.
+ *
+ * On i386, the PLT entry format is as follows:
+ *
+ * 8048300: ff 25 0c a0 04 08 jmp *0x804a00c
+ * 8048306: 68 20 00 00 00 push $0x20
+ * 804830b: e9 e0 ff ff ff jmp 80482f0 <_init+0x30>
+ *
+ * For PIE binaries it is the following:
+ *
+ * 410: ff a3 10 00 00 00 jmp *0x10(%ebx)
+ * 416: 68 00 00 00 00 push $0x0
+ * 41b: e9 d0 ff ff ff jmp 3f0 <_init+0x30>
+ *
+ * On x86_64, it is:
+ *
+ * 400420: ff 25 f2 0b 20 00 jmpq *0x200bf2(%rip) # 601018 <_GLOBAL_OFFSET_TABLE_+0x18>
+ * 400426: 68 00 00 00 00 pushq $0x0
+ * 40042b: e9 e0 ff ff ff jmpq 400410 <_init+0x18>
+ *
+ * On i386, the argument to push is an offset of relocation to
+ * use. The first PLT slot has an offset of 0x0, the second
+ * 0x8, etc. On x86_64, it's directly the index that we are
+ * looking for.
+ */
+
+ /* Here we scan the PLT table and initialize a map of
+ * relocation->slot number in lte->arch.plt_map. */
+
+ size_t i;
+ for (i = 0; i < vect_size(<e->plt_relocs); ++i) {
+
+ GElf_Addr offset = x86_plt_offset(i);
+ uint32_t reloc_arg = 0;
+
+ uint8_t byte;
+ if (elf_read_next_u8(lte->plt_data, &offset, &byte) < 0
+ || byte != 0xff
+ || elf_read_next_u8(lte->plt_data, &offset, &byte) < 0
+ || (byte != 0xa3 && byte != 0x25))
+ goto next;
+
+ /* Skip immediate argument in the instruction. */
+ offset += 4;
+
+ if (elf_read_next_u8(lte->plt_data, &offset, &byte) < 0
+ || byte != 0x68
+ || elf_read_next_u32(lte->plt_data,
+ &offset, &reloc_arg) < 0) {
+ reloc_arg = 0;
+ goto next;
+ }
+
+ if (lte->ehdr.e_machine == EM_386) {
+ if (reloc_arg % 8 != 0) {
+ reloc_arg = 0;
+ goto next;
+ }
+ reloc_arg /= 8;
+ }
+
+ next:
+ if (VECT_PUSHBACK(<e->arch.plt_map, &reloc_arg) < 0) {
+ arch_elf_destroy(lte);
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+void
+arch_elf_destroy(struct ltelf *lte)
+{
+ VECT_DESTROY(<e->arch.plt_map, uint32_t, NULL, NULL);
+}