[binutils-gdb] [GOLD] gcc-11 stringop-overflow warning

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=cd8d2039b01382a49054f2e3e0c9196e2dba5c0c

commit cd8d2039b01382a49054f2e3e0c9196e2dba5c0c
Author: Alan Modra <amodra@gmail.com>
Date:   Mon Dec 7 17:16:46 2020 +1030

    [GOLD] gcc-11 stringop-overflow warning
    
    I'm unsure why this is deserving of a warning.  Not writing the most
    efficient code surely can't be a real problem, but that is what
    https://gcc.gnu.org/bugzilla//show_bug.cgi?id=88059#c1 seems to say.
    
    plugin.cc:528:10: error: 'char* strncpy(char*, const char*, size_t)' specified bound depends on the length of the source argument [-Werror=stringop-overflow=]
      528 |   strncpy(tempdir, dir_template, len);
          |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
    plugin.cc:526:22: note: length computed here
      526 |   size_t len = strlen(dir_template) + 1;
          |                ~~~~~~^~~~~~~~~~~~~~
    
            * plugin.cc (Plugin_recorder::init): Replace strncpy with memcpy.

Diff:
---
 gold/ChangeLog | 4 ++++
 gold/plugin.cc | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/gold/ChangeLog b/gold/ChangeLog
index 05a6f26d8fb..e152e1ed698 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,7 @@
+2020-12-07  Alan Modra  <amodra@gmail.com>
+
+	* plugin.cc (Plugin_recorder::init): Replace strncpy with memcpy.
+
 2020-12-03  Alan Modra  <amodra@gmail.com>
 
 	* testsuite/Makefile.am (pr26936a.o): Pass -mx86-used-note=yes.
diff --git a/gold/plugin.cc b/gold/plugin.cc
index 729ddca9f31..fd37957e73c 100644
--- a/gold/plugin.cc
+++ b/gold/plugin.cc
@@ -525,7 +525,7 @@ Plugin_recorder::init()
 
   size_t len = strlen(dir_template) + 1;
   char* tempdir = new char[len];
-  strncpy(tempdir, dir_template, len);
+  memcpy(tempdir, dir_template, len);
 
   // Create the log file.
   std::string logname(tempdir);