Merge pull request #1411 from edenhill/safe_strerror

Thread-safe rd_strerror() (#1410)

configure.librdkafka

@@ -146,6 +146,17 @@ int foo (void) {
    return strndup(\"hi\", 2) ? 0 : 1;
 }"
 
+    # Check if strerror_r() is available.
+    # The check for GNU vs XSI is done in rdposix.h since
+    # we can't rely on all defines to be set here (_GNU_SOURCE).
+    mkl_compile_check "strerror_r" "HAVE_STRERROR_R" disable CC "" \
+"#include <string.h>
+const char *foo (void) {
+   static char buf[64];
+   strerror_r(1, buf, sizeof(buf));
+   return buf;
+}"
+
     # Check if dlopen() is available
     mkl_lib_check "libdl" "WITH_LIBDL" disable CC "-ldl" \
 "

src/rdposix.h

@@ -90,7 +90,27 @@
 /**
  * Errors
  */
+#if HAVE_STRERROR_R
+static RD_INLINE RD_UNUSED const char *rd_strerror(int err) {
+        static RD_TLS char ret[128];
+
+#if defined(__linux__) && defined(_GNU_SOURCE)
+        return strerror_r(err, ret, sizeof(ret));
+#else /* XSI version */
+        int r;
+        /* The r assignment is to catch the case where
+         * _GNU_SOURCE is not defined but the GNU version is
+         * picked up anyway. */
+        r = strerror_r(err, ret, sizeof(ret));
+        if (unlikely(r))
+                rd_snprintf(ret, sizeof(ret),
+                            "strerror_r(%d) failed (ret %d)", err, r);
+        return ret;
+#endif
+}
+#else
 #define rd_strerror(err) strerror(err)
+#endif
 
 
 /**