[src/trunk]: src/libexec/ld.elf_so Revert to version 1.55 of map_object.c. Th...

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

details:   https://anonhg.NetBSD.org/src/rev/ca6249ee1fd0
branches:  trunk
changeset: 352009:ca6249ee1fd0
user:      maya <maya%NetBSD.org@localhost>
date:      Fri Mar 10 09:13:49 2017 +0000

description:
Revert to version 1.55 of map_object.c. This reverts:

"really unmap the gap between the text and data rather than just removing
all access with mprotect().  the latter results in the kernel having to
keep track of that range separately since the permissions are different.
avoid calling mmap() with a size of zero."

As per toolchain/52054: src/libexec/ld.elf_so update breaks everything,
this commit is very broken for some people (but not others). chs mentioned
he has a fix, but best not to leave -current broken in the meantime.

diffstat:

 libexec/ld.elf_so/map_object.c |  16 ++++++----------
 1 files changed, 6 insertions(+), 10 deletions(-)

diffs (60 lines):

diff -r 4c145c49a7fd -r ca6249ee1fd0 libexec/ld.elf_so/map_object.c
--- a/libexec/ld.elf_so/map_object.c    Fri Mar 10 09:12:46 2017 +0000
+++ b/libexec/ld.elf_so/map_object.c    Fri Mar 10 09:13:49 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: map_object.c,v 1.56 2017/03/09 00:43:50 chs Exp $       */
+/*     $NetBSD: map_object.c,v 1.57 2017/03/10 09:13:49 maya Exp $      */
 
 /*
  * Copyright 1996 John D. Polstra.
@@ -34,7 +34,7 @@
 
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: map_object.c,v 1.56 2017/03/09 00:43:50 chs Exp $");
+__RCSID("$NetBSD: map_object.c,v 1.57 2017/03/10 09:13:49 maya Exp $");
 #endif /* not lint */
 
 #include <errno.h>
@@ -88,10 +88,8 @@
        Elf_Off          data_offset;
        Elf_Addr         data_vaddr;
        Elf_Addr         data_vlimit;
-       size_t           data_size;
        int              data_flags;
        caddr_t          data_addr;
-       size_t           bss_size;
 #if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
        Elf_Addr         tls_vaddr = 0; /* Noise GCC */
 #endif
@@ -363,8 +361,7 @@
 
        /* Overlay the data segment onto the proper region. */
        data_addr = mapbase + (data_vaddr - base_vaddr);
-       data_size = data_vlimit - data_vaddr;
-       if (data_size != 0 && mmap(data_addr, data_size, data_flags,
+       if (mmap(data_addr, data_vlimit - data_vaddr, data_flags,
            MAP_FILE | MAP_PRIVATE | MAP_FIXED, fd, data_offset) ==
            MAP_FAILED) {
                _rtld_error("mmap of data failed: %s", xstrerror(errno));
@@ -372,8 +369,7 @@
        }
 
        /* Overlay the bss segment onto the proper region. */
-       bss_size = base_vlimit - data_vlimit;
-       if (bss_size != 0 && mmap(mapbase + data_vlimit - base_vaddr, bss_size,
+       if (mmap(mapbase + data_vlimit - base_vaddr, base_vlimit - data_vlimit,
            data_flags, MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0) ==
            MAP_FAILED) {
                _rtld_error("mmap of bss failed: %s", xstrerror(errno));
@@ -383,8 +379,8 @@
        /* Unmap the gap between the text and data. */
        gap_addr = mapbase + round_up(text_vlimit - base_vaddr);
        gap_size = data_addr - gap_addr;
-       if (gap_size != 0 && munmap(gap_addr, gap_size) == -1) {
-               _rtld_error("munmap of text -> data gap failed: %s",
+       if (gap_size != 0 && mprotect(gap_addr, gap_size, PROT_NONE) == -1) {
+               _rtld_error("mprotect of text -> data gap failed: %s",
                    xstrerror(errno));
                goto bad;
        }