From: Érico Rolim <erico....@gmail.com>
Some C libraries don't provide the GNU version of strerror_r, only the
XSI-compliant one. We use the GNU version when available, since it fits
the code better, and otherwise use the XSI-compliant one.
Signed-off-by: Érico Rolim <erico....@gmail.com>
---
If possible, I'd like to get this patch in before the release, otherwise
it's an easy one to carry locally.
ChangeLog | 4 ++++
configure.ac | 12 ++++++++++++
libdwfl/ChangeLog | 4 ++++
libdwfl/dwfl_error.c | 17 ++++++++++++++++-
4 files changed, 36 insertions(+), 1 deletion(-)
diff --git a/ChangeLog b/ChangeLog
index 142caa27..c8f921a5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2021-02-01 Érico Nogueira <eric...@disroot.org>
+
+ * configure.ac: Check for GNU strerror_r.
+
2021-01-12 Dmitry V. Levin <l...@altlinux.org>
* configure.ac [--enable-gcov]: Check for gcov, lcov, and genhtml.
diff --git a/configure.ac b/configure.ac
index 346ab800..baf6faf5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -428,6 +428,18 @@ AC_CHECK_DECLS([mempcpy],[],[],
AC_CHECK_FUNCS([process_vm_readv])
+AC_CACHE_CHECK([whether C library provides GNU strerror_r],
ac_cv_gnu_strerror_r, [dnl
+old_CFLAGS="$CFLAGS"
+CFLAGS="$CFLAGS -Werror"
+AC_COMPILE_IFELSE([AC_LANG_SOURCE([dnl
+#define _GNU_SOURCE
+#include <string.h>
+char * (*s)(int, char*, size_t) = strerror_r;
+])], ac_cv_gnu_strerror_r=yes, ac_cv_gnu_strerror_r=no)
+CFLAGS="$old_CFLAGS"])
+AS_IF([test "x$ac_cv_gnu_strerror_r" = "xyes"],
+ [AC_DEFINE([HAVE_GNU_STRERROR_R], [1], [Defined if libc has GNU style
strerror_r])])
+
AC_CHECK_LIB([stdc++], [__cxa_demangle], [dnl
AC_DEFINE([USE_DEMANGLE], [1], [Defined if demangling is enabled])])
AM_CONDITIONAL(DEMANGLE, test "x$ac_cv_lib_stdcpp___cxa_demangle" = "xyes")
diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 5058f5f8..d107e78f 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,7 @@
+2021-02-01 Érico Nogueira <eric...@disroot.org>
+
+ * dwfl_error.c (strerror_r): Only use the GNU version when available.
+
2021-01-08 Timm Bäder <tbae...@redhat.com>
* elf-from-memory.c (elf_from_remote_memory): Add for loop over
diff --git a/libdwfl/dwfl_error.c b/libdwfl/dwfl_error.c
index 7bcf61cc..ef2834b2 100644
--- a/libdwfl/dwfl_error.c
+++ b/libdwfl/dwfl_error.c
@@ -137,6 +137,21 @@ __libdwfl_seterrno (Dwfl_Error error)
}
+static const char *
+errnomsg(int error)
+{
+ /* Won't be changed by strerror_r, but not const so compiler doesn't throw
warning */
+ static char unknown[] = "unknown error";
+
+#ifdef HAVE_GNU_STRERROR_R
+ return strerror_r (error, unknown, 0);
+#else
+ /* To store the error message from strerror_r in a thread-safe manner */
+ static __thread char msg[128];
+ return strerror_r (error, msg, sizeof (msg)) ? unknown : msg;
+#endif
+}
+
const char *
dwfl_errmsg (int error)
{
@@ -154,7 +169,7 @@ dwfl_errmsg (int error)
switch (error &~ 0xffff)
{
case OTHER_ERROR (ERRNO):
- return strerror_r (error & 0xffff, "bad", 0);
+ return errnomsg (error & 0xffff);
case OTHER_ERROR (LIBELF):
return elf_errmsg (error & 0xffff);
case OTHER_ERROR (LIBDW):
--
2.30.0
