plt.c revision f13505251e6402460f6cc7ec84e0d8ca91607b4f 
1#include <gelf.h>
2#include "ltrace.h"
3#include "elf.h"
4#include "debug.h"
5#include "ptrace.h"
6#include "options.h"
7
8GElf_Addr
9arch_plt_sym_val(struct ltelf *lte, size_t ndx, GElf_Rela * rela) {
10	return rela->r_offset;
11}
12
13void *
14sym2addr(struct process *proc, struct library_symbol *sym) {
15	void *addr = sym->enter_addr;
16	long pt_ret;
17
18	debug(3, 0);
19
20	if (sym->plt_type != LS_TOPLT_POINT) {
21		return addr;
22	}
23
24	if (proc->pid == 0) {
25		return 0;
26	}
27
28	if (opt_d >= 3) {
29		xinfdump(proc->pid, (void *)(((long)addr-32)&0xfffffff0),
30			 sizeof(void*)*8);
31	}
32
33	// On a PowerPC-64 system, a plt is three 64-bit words: the first is the
34	// 64-bit address of the routine.  Before the PLT has been initialized,
35	// this will be 0x0. In fact, the symbol table won't have the plt's
36	// address even.  Ater the PLT has been initialized, but before it has
37	// been resolved, the first word will be the address of the function in
38	// the dynamic linker that will reslove the PLT.  After the PLT is
39	// resolved, this will will be the address of the routine whose symbol
40	// is in the symbol table.
41
42	// On a PowerPC-32 system, there are two types of PLTs: secure (new) and
43	// non-secure (old).  For the secure case, the PLT is simply a pointer
44	// and we can treat it much as we do for the PowerPC-64 case.  For the
45	// non-secure case, the PLT is executable code and we can put the
46	// break-point right in the PLT.
47
48	pt_ret = ptrace(PTRACE_PEEKTEXT, proc->pid, addr, 0);
49
50	if (proc->mask_32bit) {
51		// Assume big-endian.
52		addr = (void *)((pt_ret >> 32) & 0xffffffff);
53	} else {
54		addr = (void *)pt_ret;
55	}
56
57	return addr;
58}
59