-Wstringop-truncation warnings

This patch is aimed at silencing gcc8 -Wstringop-truncation warnings.

Unfortunately adding  __attribute__ ((__nonstring)) doesn't work in a
number of the places patched here, (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85643) so if you have
recent glibc headers installed you'll need to configure binutils with
--disable-werror to compile using gcc8 or gcc9.

include/
	* ansidecl.h: Import from gcc.
	* coff/internal.h (struct internal_scnhdr): Add ATTRIBUTE_NONSTRING
	to s_name.
	(struct internal_syment): Add ATTRIBUTE_NONSTRING to _n_name.
bfd/
	* elf-linux-core.h (struct elf_external_linux_prpsinfo32_ugid32),
	(struct elf_external_linux_prpsinfo32_ugid16),
	(struct elf_external_linux_prpsinfo64_ugid32),
	(struct elf_external_linux_prpsinfo64_ugid16): Add ATTRIBUTE_NONSTRING
	to pr_fname and pr_psargs fields.  Remove GCC diagnostic pragmas.
	Move comment to..
	* elf.c (elfcore_write_prpsinfo): ..here.  Indent nested preprocessor
	directives.
	* elf32-arm.c (elf32_arm_nabi_write_core_note): Add ATTRIBUTE_NONSTRING
	to data.
	* elf32-ppc.c (ppc_elf_write_core_note): Likewise.
	* elf32-s390.c (elf_s390_write_core_note): Likewise.
	* elf64-s390.c (elf_s390_write_core_note): Likewise.
	* elfxx-aarch64.c (_bfd_aarch64_elf_write_core_note): Likewise.
	* elf64-x86-64.c (elf_x86_64_write_core_note): Add GCC diagnostic
	pragmas.
	* peXXigen.c (_bfd_XXi_swap_scnhdr_out): Use strnlen to avoid
	false positive gcc-8 warning.
gas/
	* config/obj-evax.c (shorten_identifier): Use memcpy in place
	of strncpy.
	* config/obj-macho.c (obj_mach_o_make_or_get_sect): Ensure
	segname and sectname fields are NUL terminated.

3 files changed, 18 insertions, 9 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index d7575ad..a46492b 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,10 @@
+2018-05-04  Alan Modra  <amodra@gmail.com>
+
+	* config/obj-evax.c (shorten_identifier): Use memcpy in place
+	of strncpy.
+	* config/obj-macho.c (obj_mach_o_make_or_get_sect): Ensure
+	segname and sectname fields are NUL terminated.
+
 2018-05-01  Nick Clifton  <nickc@redhat.com>
 
 	* po/es.po: Updated Spanish translation.
diff --git a/gas/config/obj-evax.c b/gas/config/obj-evax.c
index 642025f..07a7067 100644
--- a/gas/config/obj-evax.c
+++ b/gas/config/obj-evax.c
@@ -470,13 +470,13 @@ shorten_identifier (char *name)
   newname [MAX_LABEL_LENGTH] = 0;
   /* Now append the suffix of the original identifier, if any.  */
   if (suffix_length)
-  strncpy (newname + MAX_LABEL_LENGTH - suffix_length,
-	   name + len - suffix_length,
-	   suffix_length);
-  strncpy (newname + final_len, "_h", 2);
-  strncpy (newname + final_len + 2 , crc_chars, 5);
-  strncpy (newname + final_len + 2 + 5, encode_16 (len), 3);
-  strncpy (newname + final_len + 2 + 5 + 3, encode_16 (sum), 3);
+    strncpy (newname + MAX_LABEL_LENGTH - suffix_length,
+	     name + len - suffix_length,
+	     suffix_length);
+  memcpy (newname + final_len, "_h", 2);
+  memcpy (newname + final_len + 2 , crc_chars, 5);
+  memcpy (newname + final_len + 2 + 5, encode_16 (len), 3);
+  memcpy (newname + final_len + 2 + 5 + 3, encode_16 (sum), 3);
   if (!is_truncated_identifier (newname))
     abort ();
   return newname;
diff --git a/gas/config/obj-macho.c b/gas/config/obj-macho.c
index 4911907..3ee98b9 100644
--- a/gas/config/obj-macho.c
+++ b/gas/config/obj-macho.c
@@ -250,8 +250,10 @@ obj_mach_o_make_or_get_sect (char * segname, char * sectname,
 		 bfd_section_name (stdoutput, sec),
 		 bfd_errmsg (bfd_get_error ()));
 
-      strncpy (msect->segname, segname, sizeof (msect->segname));
-      strncpy (msect->sectname, sectname, sizeof (msect->sectname));
+      strncpy (msect->segname, segname, BFD_MACH_O_SEGNAME_SIZE);
+      msect->segname[BFD_MACH_O_SEGNAME_SIZE] = 0;
+      strncpy (msect->sectname, sectname, BFD_MACH_O_SECTNAME_SIZE);
+      msect->sectname[BFD_MACH_O_SECTNAME_SIZE] = 0;
 
       msect->align = secalign;
       msect->flags = sectype | secattr;