Add SSSD specific error codes and definitions

This code adds a new range of error codes specific to SSSD,
It also provides helper functions to print out error defintions
like you can do with system error messages and the strerror() function.

The sss_strerror() function can accept both the new sssd errors and
system errno_t errors falling back to the system strerror() if the error
code provide is not a valid SSSD error code.

4 files changed, 120 insertions, 8 deletions

diff --git a/Makefile.am b/Makefile.am
index 4ff02b8e7..79e6e571c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -363,6 +363,7 @@ dist_noinst_HEADERS = \
     src/util/crypto/sss_crypto.h \
     src/util/dlinklist.h \
     src/util/util.h \
+    src/util/util_errors.h \
     src/util/strtonum.h \
     src/util/sss_nss.h \
     src/util/sss_ldap.h \
@@ -524,7 +525,8 @@ libsss_util_la_SOURCES = \
     src/util/authtok.c \
     src/util/sss_selinux.c \
     src/util/domain_info_utils.c \
-    src/util/util_lock.c
+    src/util/util_lock.c \
+    src/util/util_errors.c
 libsss_util_la_LIBADD = \
     $(SSSD_LIBS) \
     $(UNICODE_LIBS) \
diff --git a/src/util/util.h b/src/util/util.h
index 7026f0b93..9657826e2 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -44,11 +44,7 @@
 #include <dhash.h>
 
 #include "util/atomic_io.h"
-
-#ifndef HAVE_ERRNO_T
-#define HAVE_ERRNO_T
-typedef int errno_t;
-#endif
+#include "util/util_errors.h"
 
 #define _(STRING) gettext (STRING)
 
@@ -221,8 +217,6 @@ errno_t set_debug_file_from_fd(const int fd);
 
 #define ZERO_STRUCT(x) memset((char *)&(x), 0, sizeof(x))
 
-#define EOK 0
-
 #define SSSD_MAIN_OPTS SSSD_DEBUG_OPTS
 
 #define FLAGS_NONE 0x0000
diff --git a/src/util/util_errors.c b/src/util/util_errors.c
new file mode 100644
index 000000000..92dced3c5
--- /dev/null
+++ b/src/util/util_errors.c
@@ -0,0 +1,41 @@
+/*
+    Copyright (C) 2012 Red Hat
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+    Authors:
+        Simo Sorce <ssorce@redhat.com>
+*/
+
+#include "util/util.h"
+
+struct err_string {
+    const char *msg;
+};
+
+struct err_string error_to_str[] = {
+    { "Invalid Error" },        /* ERR_INVALID */
+    { "Internal Error" },       /* ERR_INTERNAL */
+};
+
+
+const char *sss_strerror(errno_t error)
+{
+    if (IS_SSSD_ERROR(error)) {
+        return error_to_str[SSSD_ERR_IDX(error)].msg;
+    }
+
+    return strerror(error);
+}
+
diff --git a/src/util/util_errors.h b/src/util/util_errors.h
new file mode 100644
index 000000000..eb0df77e6
--- /dev/null
+++ b/src/util/util_errors.h
@@ -0,0 +1,75 @@
+/*
+    Copyright (C) 2012 Red Hat
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+    Authors:
+        Simo Sorce <ssorce@redhat.com>
+*/
+
+#ifndef __SSSD_UTIL_ERRORS_H__
+#define __SSSD_UTIL_ERRORS_H__
+
+#ifndef HAVE_ERRNO_T
+#define HAVE_ERRNO_T
+typedef int errno_t;
+#endif
+
+/*
+ * We define a specific number space so that we do not overlap with other
+ * generic errors returned by various libraries. This will make it easy
+ * to have functions that double check that what was returned was a SSSD
+ * specific error where it matters. For example we may want to ensure some
+ * particularly sensitive paths only return SSSD sepcific errors as that
+ * will insure all error conditions have been explicitly dealt with,
+ * and are not the result of assigning the wrong return result.
+ *
+ * Basic system errno errors can still be used, but when an error condition
+ * does not properly map to a system error we should use a SSSD specific one
+ */
+
+#define ERR_BASE    0x555D0000
+#define ERR_MASK    0x0000FFFF
+
+/* never use ERR_INVALID, it is used for catching and returning
+ * information on invalid error numbers */
+/* never use ERR_LAST, this represent the maximum error value available
+ * and is used to validate error codes */
+enum sssd_errors {
+    ERR_INVALID = ERR_BASE + 0,
+    ERR_INTERNAL,
+    ERR_LAST            /* ALWAYS LAST */
+};
+
+#define SSSD_ERR_IDX(err) ((err) & ERR_MASK)
+#define IS_SSSD_ERROR(err) \
+    ((((err) & ERR_BASE) == ERR_BASE) && \
+     SSSD_ERR_IDX(err) < ERR_LAST)
+
+#define ERR_OK      0
+/* Backwards compat */
+#ifndef EOK
+#define EOK ERR_OK
+#endif
+
+/**
+ * @brief return a string descriing the error number like strerror()
+ *
+ * @param error     An errno_t number, can be a SSSD error or a system error
+ *
+ * @return A statically allocated string.
+ */
+const char *sss_strerror(errno_t error);
+
+#endif /* __SSSD_UTIL_ERRORS_H__ */