[src/trunk]: src/lib/libexecinfo make this work with pie binaries (subtract d...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3447959691ea
branches:  trunk
changeset: 344697:3447959691ea
user:      christos <christos%NetBSD.org@localhost>
date:      Mon Apr 11 15:30:18 2016 +0000

description:
make this work with pie binaries (subtract dli_fbase from addresses).

diffstat:

 lib/libexecinfo/symtab.c |  30 +++++++++++++++++++++++++-----
 1 files changed, 25 insertions(+), 5 deletions(-)

diffs (77 lines):

diff -r e548c1c59fac -r 3447959691ea lib/libexecinfo/symtab.c
--- a/lib/libexecinfo/symtab.c  Mon Apr 11 14:15:30 2016 +0000
+++ b/lib/libexecinfo/symtab.c  Mon Apr 11 15:30:18 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: symtab.c,v 1.3 2013/09/03 08:44:45 christos Exp $      */
+/*     $NetBSD: symtab.c,v 1.4 2016/04/11 15:30:18 christos Exp $      */
 
 /*-
  * Copyright (c) 2012 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__RCSID("$NetBSD: symtab.c,v 1.3 2013/09/03 08:44:45 christos Exp $");
+__RCSID("$NetBSD: symtab.c,v 1.4 2016/04/11 15:30:18 christos Exp $");
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -47,7 +47,6 @@
 #define ELF_ST_TYPE(x)          (((unsigned int)x) & 0xf)
 #endif
 
-
 #include "symtab.h"
 
 struct symbol {
@@ -127,6 +126,13 @@
                        GElf_Sym sym;
                         gelf_getsym(edata, (int)i, &sym);
 
+#ifdef SYMTAB_DEBUG
+                       fprintf(stderr, "%s: %s@%#jx=%d,%d\n", __func__,
+                           elf_strptr(elf, shdr.sh_link, sym.st_name),
+                           (uintmax_t)sym.st_value, ELF_ST_BIND(sym.st_info),
+                           ELF_ST_TYPE(sym.st_info));
+#endif
+                       
                        if (bind != -1 &&
                            (unsigned)bind != ELF_ST_BIND(sym.st_info))
                                continue;
@@ -170,8 +176,13 @@
        size_t hi = ns;
        size_t lo = 0;
        size_t mid = ns / 2;
-       uintptr_t dd, sd, me = (uintptr_t)p;
+       uintptr_t dd, sd, me = (uintptr_t)p - (uintptr_t)dli->dli_fbase;
+       uintptr_t ad = (uintptr_t)dli->dli_saddr - (uintptr_t)dli->dli_fbase;
 
+#ifdef SYMTAB_DEBUG
+       fprintf(stderr, "%s: [fbase=%p, saddr=%p, me=%#jx]\n", __func__,
+           dli->dli_fbase, dli->dli_saddr, (uintmax_t)me);
+#endif
        for (;;) {
                if (s[mid].st_value < me)
                        lo = mid;
@@ -185,11 +196,20 @@
                }
                mid = (hi + lo) / 2;
        }
-       dd = me - (uintptr_t)dli->dli_saddr;
+       dd = me - ad;
        sd = me - s[mid].st_value;
        if (dd > sd) {
                dli->dli_saddr = (void *)s[mid].st_value;
                dli->dli_sname = s[mid].st_name;
+#ifdef SYMTAB_DEBUG
+               fprintf(stderr, "%s: %p -> [%p, %s]\n", __func__,
+                   p, dli->dli_saddr, dli->dli_sname);
+#endif
        }
+#ifdef SYMTAB_DEBUG
+       else
+               fprintf(stderr, "%s: %p -> [%p, ***]\n", __func__,
+                   p, dli->dli_saddr);
+#endif
        return 1;
 }