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emacs/emacs-24-0014-ELF-unexec-_OBJC_-symbols-in-bss-sections.patch
2016-02-13 15:52:25 +00:00

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From af11708e83ab826202593ab1b9c22601c46a5056 Mon Sep 17 00:00:00 2001
From: Alan Modra <amodra@gmail.com>
Date: Sun, 8 Nov 2015 09:29:00 -0800
Subject: ELF unexec: _OBJC_ symbols in bss sections
Emacs should build on ppc64el. A problem with the bss has been fixed.
This upstream patch has been added [5/10]:
ELF unexec: _OBJC_ symbols in bss sections
This code assumed that there was only one bss section. Rather than
checking for a particular index, check the section type. Also, handle
the possibility that the section was SHT_NOBITS originally and is
unchanged, in which case no clearing is needed (and sh_offset isn't
necessarily valid, which can lead to a wild memset).
* unexelf.c (unexec): Properly handle _OBJC_ symbols in bss sections.
Origin: upstream, commit: 3ff9fc0e8d738be5004c65c3be314af9aca68148
Bug: http://debbugs.gnu.org/20614
Bug-Debian: http://bugs.debian.org/808347
Added-by: Rob Browning <rlb@defaultvalue.org>
---
src/unexelf.c | 31 ++++++++++++++++++-------------
1 file changed, 18 insertions(+), 13 deletions(-)
diff --git a/src/unexelf.c b/src/unexelf.c
index 010ecd3..58f0ad0 100644
--- a/src/unexelf.c
+++ b/src/unexelf.c
@@ -1177,20 +1177,25 @@ temacs:
"_OBJC_", sizeof ("_OBJC_") - 1) == 0)
{
ElfW (Shdr) *new_shdr = &NEW_SECTION_H (symp->st_shndx);
- ptrdiff_t reladdr = symp->st_value - new_shdr->sh_addr;
- ptrdiff_t newoff = reladdr + new_shdr->sh_offset;
-
- /* "Unpatch" index. */
- nn = symp->st_shndx;
- if (nn > old_bss_index)
- nn--;
- if (nn == old_bss_index)
- memset (new_base + newoff, 0, symp->st_size);
- else
+ if (new_shdr->sh_type != SHT_NOBITS)
{
- ElfW (Shdr) *old_shdr = &OLD_SECTION_H (nn);
- ptrdiff_t oldoff = reladdr + old_shdr->sh_offset;
- memcpy (new_base + newoff, old_base + oldoff, symp->st_size);
+ ElfW (Shdr) *old_shdr;
+ ptrdiff_t reladdr = symp->st_value - new_shdr->sh_addr;
+ ptrdiff_t newoff = reladdr + new_shdr->sh_offset;
+
+ /* "Unpatch" index. */
+ nn = symp->st_shndx;
+ if (nn > old_bss_index)
+ nn--;
+ old_shdr = &OLD_SECTION_H (nn);
+ if (old_shdr->sh_type == SHT_NOBITS)
+ memset (new_base + newoff, 0, symp->st_size);
+ else
+ {
+ ptrdiff_t oldoff = reladdr + old_shdr->sh_offset;
+ memcpy (new_base + newoff, old_base + oldoff,
+ symp->st_size);
+ }
}
}
#endif