eal: cleanup strerror function

When compiled on Ubuntu with extra warnings enabled, the rte_strerror()
function triggered a warning about an unused return value from
strerror_r(). Rather than always have this warning disabled, we fix this,
and in the process do some cleanup of the code so as to reduce the
complexity of the fix, e.g. not having the #ifdef macros inside the
snprintf call.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Harry van Haaren <harry.van.haaren@intel.com>

diff --git a/lib/librte_eal/common/eal_common_errno.c b/lib/librte_eal/common/eal_common_errno.c
index de48d8e..dc5b7c0 100644 (file)
--- a/lib/librte_eal/common/eal_common_errno.c
+++ b/lib/librte_eal/common/eal_common_errno.c
@@ -46,18 +46,20 @@ RTE_DEFINE_PER_LCORE(int, _rte_errno);
 const char *
 rte_strerror(int errnum)
 {
+       /* BSD puts a colon in the "unknown error" messages, Linux doesn't */
+#ifdef RTE_EXEC_ENV_BSDAPP
+       static const char *sep = ":";
+#else
+       static const char *sep = "";
+#endif
 #define RETVAL_SZ 256
        static RTE_DEFINE_PER_LCORE(char[RETVAL_SZ], retval);
+       char *ret = RTE_PER_LCORE(retval);
 
        /* since some implementations of strerror_r throw an error
         * themselves if errnum is too big, we handle that case here */
-       if (errnum > RTE_MAX_ERRNO)
-               snprintf(RTE_PER_LCORE(retval), RETVAL_SZ,
-#ifdef RTE_EXEC_ENV_BSDAPP
-                               "Unknown error: %d", errnum);
-#else
-                               "Unknown error %d", errnum);
-#endif
+       if (errnum >= RTE_MAX_ERRNO)
+               snprintf(ret, RETVAL_SZ, "Unknown error%s %d", sep, errnum);
        else
                switch (errnum){
                case E_RTE_SECONDARY:
@@ -65,8 +67,10 @@ rte_strerror(int errnum)
                case E_RTE_NO_CONFIG:
                        return "Missing rte_config structure";
                default:
-                       strerror_r(errnum, RTE_PER_LCORE(retval), RETVAL_SZ);
+                       if (strerror_r(errnum, ret, RETVAL_SZ) != 0)
+                               snprintf(ret, RETVAL_SZ, "Unknown error%s %d",
+                                               sep, errnum);
                }
 
-       return RTE_PER_LCORE(retval);
+       return ret;
 }