plt.c revision 7bd88f51d4305f093ec45f557a0bde69ce5a7d11 
1#include <gelf.h>
2
3#include "proc.h"
4#include "common.h"
5#include "library.h"
6
7/* A bundle is 128 bits */
8#define BUNDLE_SIZE 16
9
10/*
11
12  The PLT has
13
14  ] 3 bundles as a header
15
16  ] The special reserved entry
17
18  ] Following that, each PLT entry has it's initial code that the GOT entry
19    points to.  Each PLT entry has one bundle allocated.
20
21  ] Following that, each PLT entry has two bundles of actual PLT code,
22    i.e. load up the address from the GOT and jump to it.  This is the
23    point we want to insert the breakpoint, as this will be captured
24    every time we jump to the PLT entry in the code.
25
26*/
27
28GElf_Addr
29arch_plt_sym_val(struct ltelf *lte, size_t ndx, GElf_Rela * rela) {
30	/* Find number of entires by removing header and special
31	 * entry, dividing total size by three, since each PLT entry
32	 * will have 3 bundles (1 for inital entry and two for the PLT
33	 * code). */
34	int entries = (lte->plt_size - 4 * BUNDLE_SIZE) / (3 * BUNDLE_SIZE);
35
36	/* Now the point we want to break on is the PLT entry after
37	 * all the header stuff */
38	unsigned long addr =
39	    lte->plt_addr + (4 * BUNDLE_SIZE) + (BUNDLE_SIZE * entries) +
40	    (2 * ndx * BUNDLE_SIZE);
41	debug(3, "Found PLT %zd entry at %lx\n", ndx, addr);
42
43	return addr;
44}
45
46void *
47sym2addr(Process *proc, struct library_symbol *sym) {
48	return sym->enter_addr;
49}
50