diff options
Diffstat (limited to 'src/unexelf.c')
| -rw-r--r-- | src/unexelf.c | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/src/unexelf.c b/src/unexelf.c index 7fad64fab17..756de5835ce 100644 --- a/src/unexelf.c +++ b/src/unexelf.c @@ -14,7 +14,7 @@ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License -along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ +along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */ /* In other words, you are welcome to use, share and improve this program. @@ -58,9 +58,11 @@ what you give them. Help stamp out software-hoarding! */ #include <sys/types.h> #include <unistd.h> -#if !defined (__NetBSD__) && !defined (__OpenBSD__) -#include <elf.h> -#endif /* not __NetBSD__ and not __OpenBSD__ */ +#ifdef __QNX__ +# include <sys/elf.h> +#elif !defined __NetBSD__ && !defined __OpenBSD__ +# include <elf.h> +#endif #include <sys/mman.h> #if defined (_SYSTYPE_SYSV) #include <sys/elf_mips.h> @@ -222,7 +224,6 @@ unexec (const char *new_name, const char *old_name) { int new_file, old_file; off_t new_file_size; - void *new_break; /* Pointers to the base of the image of the two files. */ caddr_t old_base, new_base; @@ -326,11 +327,13 @@ unexec (const char *new_name, const char *old_name) if (old_bss_index == -1) fatal ("no bss section found"); + void *no_break = (void *) (intptr_t) -1; + void *new_break = no_break; #ifdef HAVE_SBRK new_break = sbrk (0); -#else - new_break = (byte *) old_bss_addr + old_bss_size; #endif + if (new_break == no_break) + new_break = (byte *) old_bss_addr + old_bss_size; new_bss_addr = (ElfW (Addr)) new_break; bss_size_growth = new_bss_addr - old_bss_addr; new_data2_size = bss_size_growth; @@ -576,7 +579,17 @@ unexec (const char *new_name, const char *old_name) } /* This loop seeks out relocation sections for the data section, so - that it can undo relocations performed by the runtime loader. */ + that it can undo relocations performed by the runtime loader. + + The following approach does not work on x86 platforms that use + the GNU Gold linker, which can generate .rel.dyn relocation + sections containing R_386_32 entries that the following code does + not grok. Emacs works around this problem by avoiding C + constructs that generate such entries, which is horrible hack. + + FIXME: Presumably more problems like this will crop up as linkers + get fancier. We really need to stop assuming that Emacs can grok + arbitrary linker output. See Bug#27248. */ for (n = new_file_h->e_shnum; 0 < --n; ) { ElfW (Shdr) *rel_shdr = &NEW_SECTION_H (n); |