string: Add strerrorname_np and strerrordesc_np

The strerrorname_np returns error number name (e.g. "EINVAL" for EINVAL)
while strerrordesc_np returns string describing error number (e.g
"Invalid argument" for EINVAL).  Different than strerror,
strerrordesc_np does not attempt to translate the return description,
both functions return NULL for an invalid error number.

They should be used instead of sys_errlist and sys_nerr, both are
thread and async-signal safe.  These functions are GNU extensions.

Checked on x86-64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
and s390x-linux-gnu.

Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>

5 files changed, 61 insertions, 1 deletions

diff --git a/string/Makefile b/string/Makefile
index 8fe7e17..f8d3104 100644
--- a/string/Makefile
+++ b/string/Makefile
@@ -45,7 +45,8 @@ routines	:= strcat strchr strcmp strcoll strcpy strcspn		\
 		   envz basename					\
 		   strcoll_l strxfrm_l string-inlines memrchr		\
 		   xpg-strerror strerror_l explicit_bzero		\
-		   sigdescr_np sigabbrev_np
+		   sigdescr_np sigabbrev_np strerrorname_np		\
+		   strerrordesc_np
 
 strop-tests	:= memchr memcmp memcpy memmove mempcpy memset memccpy	\
 		   stpcpy stpncpy strcat strchr strcmp strcpy strcspn	\
diff --git a/string/Versions b/string/Versions
index 6f8dd2d..298ecd4 100644
--- a/string/Versions
+++ b/string/Versions
@@ -87,5 +87,6 @@ libc {
   }
   GLIBC_2.32 {
     sigdescr_np; sigabbrev_np;
+    strerrordesc_np; strerrorname_np;
   }
 }
diff --git a/string/strerrordesc_np.c b/string/strerrordesc_np.c
new file mode 100644
index 0000000..cdaf3a7
--- /dev/null
+++ b/string/strerrordesc_np.c
@@ -0,0 +1,26 @@
+/* Return string describing error number.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+
+const char *
+__strerrordesc_np (int errnum)
+{
+  return __get_errlist (errnum);
+}
+weak_alias (__strerrordesc_np, strerrordesc_np)
diff --git a/string/strerrorname_np.c b/string/strerrorname_np.c
new file mode 100644
index 0000000..bc337d2
--- /dev/null
+++ b/string/strerrorname_np.c
@@ -0,0 +1,25 @@
+/* Return string describing errno name.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+
+const char *
+strerrorname_np (int errnum)
+{
+  return __get_errname (errnum);
+}
diff --git a/string/string.h b/string/string.h
index 0119d7f..b0be00c 100644
--- a/string/string.h
+++ b/string/string.h
@@ -428,6 +428,13 @@ extern int __xpg_strerror_r (int __errnum, char *__buf, size_t __buflen)
 extern char *strerror_r (int __errnum, char *__buf, size_t __buflen)
      __THROW __nonnull ((2)) __wur  __attr_access ((__write_only__, 2, 3));
 # endif
+
+# ifdef __USE_GNU
+/* Return a string describing the meaning of tthe error in ERR.  */
+extern const char *strerrordesc_np (int __err) __THROW;
+/* Return a string with the error name in ERR.  */
+extern const char *strerrorname_np (int __err) __THROW;
+# endif
 #endif
 
 #ifdef __USE_XOPEN2K8