From 0de7316751e94c29aeb4b75731ac6e8c9eba77e6 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Mon, 16 Nov 2015 17:48:08 -0800 Subject: ELF unexec: align section header MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Emacs should build on ppc64el. A problem with the bss has been fixed. This upstream patch has been added [10/10]: ELF unexec: align section header This ports the recent unexelf.c changes to Fedora x86-64 when configured with GCC’s -fsanitize=undefined option. * src/unexelf.c (unexec): Align new_data2_size to a multiple of ElfW (Shdr)’s alignment, so that NEW_SECTION_H returns a pointer aligned appropriately for its type. Origin: upstream, commit: c9fd597a4cffcae873b25381ee8cc755f0debe95 Bug: http://debbugs.gnu.org/20614 Bug-Debian: http://bugs.debian.org/808347 Added-by: Rob Browning --- src/unexelf.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) Index: emacs-24.5/src/unexelf.c =================================================================== --- emacs-24.5.orig/src/unexelf.c +++ emacs-24.5/src/unexelf.c @@ -247,7 +247,7 @@ unexec (const char *new_name, const char ElfW (Phdr) *old_bss_seg, *new_bss_seg; ElfW (Addr) old_bss_addr, new_bss_addr; - ElfW (Word) old_bss_size, new_data2_size; + ElfW (Word) old_bss_size, bss_size_growth, new_data2_size; ElfW (Off) old_bss_offset, new_data2_offset; ptrdiff_t n; @@ -332,7 +332,11 @@ unexec (const char *new_name, const char new_break = sbrk (0); new_bss_addr = (ElfW (Addr)) new_break; - new_data2_size = new_bss_addr - old_bss_addr; + bss_size_growth = new_bss_addr - old_bss_addr; + new_data2_size = bss_size_growth; + new_data2_size += alignof (ElfW (Shdr)) - 1; + new_data2_size -= new_data2_size % alignof (ElfW (Shdr)); + new_data2_offset = old_bss_offset; #ifdef UNEXELF_DEBUG @@ -400,7 +404,8 @@ unexec (const char *new_name, const char new_bss_seg->p_memsz = new_bss_seg->p_filesz; /* Copy over what we have in memory now for the bss area. */ - memcpy (new_base + new_data2_offset, (caddr_t) old_bss_addr, new_data2_size); + memcpy (new_base + new_data2_offset, (caddr_t) old_bss_addr, + bss_size_growth); /* Walk through all section headers, copying data and updating. */ for (n = 1; n < old_file_h->e_shnum; n++)