[review] Use strerror_r in safe_strerror if available

["Christian Biesinger (Code Review)" <gerrit@gnutoolchain-gerrit.osci.io>]

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/474
......................................................................

Use strerror_r in safe_strerror if available

Also stores the result in a thread-local static variable.

This is already important because Guile creates threads and
Python can create threads, but with the patch series here:
https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/176
GDB itself will create threads, too.

gdb/ChangeLog:

2019-10-31  Christian Biesinger  <cbiesinger@google.com>

	* configure: Regenerate.
	* configure.ac: Check for strerror_r.
	* gdbsupport/posix-strerror.c (safe_strerror): Make buf
	thread_local and call strerror_r, if available.

Change-Id: I81048fbaf148035c221c528727f7efe58ba528eb
---
M gdb/configure
M gdb/configure.ac
M gdb/gdbsupport/posix-strerror.c
3 files changed, 15 insertions(+), 5 deletions(-)



diff --git a/gdb/configure b/gdb/configure
index e805903..018cc4b 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -13073,7 +13073,7 @@
 		sigaction sigsetmask socketpair \
 		ttrace wborder wresize setlocale iconvlist libiconvlist btowc \
 		setrlimit getrlimit posix_madvise waitpid \
-		ptrace64 sigaltstack setns use_default_colors
+		ptrace64 sigaltstack setns use_default_colors strerror_r
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 354bb7b..987507a 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1318,7 +1318,7 @@
 		sigaction sigsetmask socketpair \
 		ttrace wborder wresize setlocale iconvlist libiconvlist btowc \
 		setrlimit getrlimit posix_madvise waitpid \
-		ptrace64 sigaltstack setns use_default_colors])
+		ptrace64 sigaltstack setns use_default_colors strerror_r])
 AM_LANGINFO_CODESET
 GDB_AC_COMMON
 
diff --git a/gdb/gdbsupport/posix-strerror.c b/gdb/gdbsupport/posix-strerror.c
index a8651b7..727eb7b 100644
--- a/gdb/gdbsupport/posix-strerror.c
+++ b/gdb/gdbsupport/posix-strerror.c
@@ -24,12 +24,22 @@
 char *
 safe_strerror (int errnum)
 {
-  char *msg;
+  static thread_local char buf[1024];
 
+  char *msg = nullptr;
+#ifdef HAVE_STRERROR_R
+#if !__GLIBC__ || ((_POSIX_C_SOURCE >= 200112L) && !  _GNU_SOURCE)
+  /* Glibc has two different, incompatible versions of strerror_r.  */
+  if (strerror_r (errnum, buf, sizeof (buf)) == 0)
+    msg = buf;
+#else
+  msg = strerror_r (errnum, buf, sizeof (buf));
+#endif
+#else
   msg = strerror (errnum);
-  if (msg == NULL)
+#endif
+  if (msg == nullptr)
     {
-      static char buf[32];
 
       xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum);
       msg = buf;

-- 
Gerrit-Project: binutils-gdb
Gerrit-Branch: master
Gerrit-Change-Id: I81048fbaf148035c221c528727f7efe58ba528eb
Gerrit-Change-Number: 474
Gerrit-PatchSet: 1
Gerrit-Owner: Christian Biesinger <cbiesinger@google.com>
Gerrit-MessageType: newchange