plt.c revision 2a61d19bd244dadcde5009f1632cf14b95623e3d 
1#include <gelf.h>
2#include "common.h"
3
4GElf_Addr
5arch_plt_sym_val(struct ltelf *lte, size_t ndx, GElf_Rela * rela) {
6	return rela->r_offset;
7}
8
9void *
10sym2addr(Process *proc, struct library_symbol *sym) {
11	void *addr = sym->enter_addr;
12	long pt_ret;
13
14	debug(3, 0);
15
16	if (sym->plt_type != LS_TOPLT_POINT) {
17		return addr;
18	}
19
20	if (proc->pid == 0) {
21		return 0;
22	}
23
24	if (options.debug >= 3) {
25		xinfdump(proc->pid, (void *)(((long)addr-32)&0xfffffff0),
26			 sizeof(void*)*8);
27	}
28
29	// On a PowerPC-64 system, a plt is three 64-bit words: the first is the
30	// 64-bit address of the routine.  Before the PLT has been initialized,
31	// this will be 0x0. In fact, the symbol table won't have the plt's
32	// address even.  Ater the PLT has been initialized, but before it has
33	// been resolved, the first word will be the address of the function in
34	// the dynamic linker that will reslove the PLT.  After the PLT is
35	// resolved, this will will be the address of the routine whose symbol
36	// is in the symbol table.
37
38	// On a PowerPC-32 system, there are two types of PLTs: secure (new) and
39	// non-secure (old).  For the secure case, the PLT is simply a pointer
40	// and we can treat it much as we do for the PowerPC-64 case.  For the
41	// non-secure case, the PLT is executable code and we can put the
42	// break-point right in the PLT.
43
44	pt_ret = ptrace(PTRACE_PEEKTEXT, proc->pid, addr, 0);
45
46	if (proc->mask_32bit) {
47		// Assume big-endian.
48		addr = (void *)((pt_ret >> 32) & 0xffffffff);
49	} else {
50		addr = (void *)pt_ret;
51	}
52
53	return addr;
54}
55