[src/trunk]: src/lib/libc/dlfcn Compute relocbase correctly for static PIE. A...

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

details:   https://anonhg.NetBSD.org/src/rev/1053e7c0c3ff
branches:  trunk
changeset: 324632:1053e7c0c3ff
user:      joerg <joerg%NetBSD.org@localhost>
date:      Fri Jul 13 19:49:47 2018 +0000

description:
Compute relocbase correctly for static PIE. AT_BASE is not usable in
this case.

diffstat:

 lib/libc/dlfcn/dlfcn_elf.c |  15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diffs (36 lines):

diff -r b1e730ad1c1a -r 1053e7c0c3ff lib/libc/dlfcn/dlfcn_elf.c
--- a/lib/libc/dlfcn/dlfcn_elf.c        Fri Jul 13 19:44:08 2018 +0000
+++ b/lib/libc/dlfcn/dlfcn_elf.c        Fri Jul 13 19:49:47 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: dlfcn_elf.c,v 1.15 2018/01/05 19:29:44 kamil Exp $     */
+/*     $NetBSD: dlfcn_elf.c,v 1.16 2018/07/13 19:49:47 joerg Exp $     */
 
 /*
  * Copyright (c) 2000 Takuya SHIOZAKI
@@ -27,7 +27,7 @@
 
 #include <sys/cdefs.h>
 #if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: dlfcn_elf.c,v 1.15 2018/01/05 19:29:44 kamil Exp $");
+__RCSID("$NetBSD: dlfcn_elf.c,v 1.16 2018/07/13 19:49:47 joerg Exp $");
 #endif /* LIBC_SCCS and not lint */
 
 #include "namespace.h"
@@ -176,6 +176,17 @@
                        break;
                }
        }
+
+       if (!dlpi_phdr)
+               return;
+
+       const Elf_Phdr *phdr = (const Elf_Phdr *)dlpi_phdr;
+       const Elf_Phdr *phlimit = phdr + dlpi_phnum;
+
+       for (; phdr < phlimit; ++phdr) {
+               if (phdr->p_type == PT_PHDR)
+                       dlpi_addr = (uintptr_t)phdr - phdr->p_vaddr;
+       }
 }
 
 /*ARGSUSED*/