log: enhance syslog logging using CEE format

This patch enables to use syslog as log target in addition to the
default.  The logs are sent in CEE format (http://cee.mitre.org/).
This logging can be disabled using compile time option by

./configure --disable-syslog
(or)
rpmbuild glusterfs.tar.gz --without syslog

The framework provides two api

void gf_openlog (const char *ident, int option, int facility);
void gf_syslog (int error_code, int facility_priority, char *format, ...);

consumers need to call gf_openlog() prior to gf_syslog() like the way
traditional syslog function calls.  error_code is mandatory when using
gf_syslog().  For example,

gf_openlog (NULL, -1, -1);
gf_syslog (GF_ERR_DEV, LOG_ERR, "error reading configuration file");

Using syslog, admin is free to configure logger to
* reduce repeated log messages
* forward logs to remote logger
* execute a command on certain log pattern
* alert people for certain log pattern by email, snmp etc
* and many more

Change-Id: Ibacbcbbc547192893fc4a46b387496b622e4811f
BUG: 928648
Signed-off-by: Bala.FA <barumuga@redhat.com>
Reviewed-on: http://review.gluster.org/4915
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

3 files changed, 231 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index 896c2415a6f..94e0878113d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -658,6 +658,20 @@ fi
 AC_SUBST(CFLAGS)
 # end enable debug section
 
+# syslog section
+AC_ARG_ENABLE([syslog],
+	      AC_HELP_STRING([--disable-syslog],
+			     [Disable syslog for logging]))
+
+USE_SYSLOG="yes"
+if test "x$enable_syslog" != "xno"; then
+  AC_DEFINE(GF_USE_SYSLOG, 1, [Use syslog for logging])
+else
+  USE_SYSLOG="no"
+fi
+AM_CONDITIONAL([ENABLE_SYSLOG], [test x$USE_SYSLOG = xyes])
+#end syslog section
+
 BUILD_READLINE=no
 AC_CHECK_LIB([readline -lcurses],[readline],[RLLIBS="-lreadline -lcurses"])
 AC_CHECK_LIB([readline -ltermcap],[readline],[RLLIBS="-lreadline -ltermcap"])
@@ -768,4 +782,5 @@ echo "Enable Debug         : $BUILD_DEBUG"
 echo "systemtap            : $BUILD_SYSTEMTAP"
 echo "Block Device backend : $BUILD_BD_XLATOR"
 echo "glupy                : $BUILD_GLUPY"
+echo "Use syslog           : $USE_SYSLOG"
 echo
diff --git a/glusterfs.spec.in b/glusterfs.spec.in
index 85c656d7277..96918fac3a2 100644
--- a/glusterfs.spec.in
+++ b/glusterfs.spec.in
@@ -31,6 +31,10 @@
 # rpmbuild -ta @PACKAGE_NAME@-@PACKAGE_VERSION@.tar.gz --without ocf
 %{?_without_ocf:%global _without_ocf --without-ocf}
 
+# if you wish to build rpms without syslog logging, compile like this
+# rpmbuild -ta @PACKAGE_NAME@-@PACKAGE_VERSION@tar.gz --without syslog
+%{?_without_syslog:%global _without_syslog --disable-syslog}
+
 %if ( 0%{?fedora} && 0%{?fedora} > 16 ) || ( 0%{?rhel} && 0%{?rhel} > 6 )
 %global           _with_systemd true
 %endif
@@ -323,7 +327,7 @@ This package provides the api include files.
 
 %build
 ./autogen.sh
-%configure %{?_without_rdma} %{?_without_epoll} %{?_without_fusermount} %{?_without_georeplication} %{?_without_ocf}
+%configure %{?_without_rdma} %{?_without_epoll} %{?_without_fusermount} %{?_without_georeplication} %{?_without_ocf} %{?_without_syslog}
 
 # fix hardening and remove rpath in shlibs
 %if ( 0%{?fedora} && 0%{?fedora} > 17 ) || ( 0%{?rhel} && 0%{?rhel} > 6 )
diff --git a/libglusterfs/src/logging.c b/libglusterfs/src/logging.c
index 65613f9852c..b74a4866995 100644
--- a/libglusterfs/src/logging.c
+++ b/libglusterfs/src/logging.c
@@ -22,6 +22,16 @@
 #include <string.h>
 #include <stdlib.h>
 
+#ifdef GF_USE_SYSLOG
+#include <libintl.h>
+#include <syslog.h>
+#include "gf-error-codes.h"
+
+#define GF_JSON_MSG_LENGTH      8192
+#define GF_SYSLOG_CEE_FORMAT    \
+        "@cee: {\"msg\": \"%s\", \"gf_code\": \"%u\", \"gf_message\": \"%s\"}"
+#endif /* GF_USE_SYSLOG */
+
 #include "xlator.h"
 #include "logging.h"
 #include "defaults.h"
@@ -102,6 +112,207 @@ gf_log_fini (void)
 }
 
 
+#ifdef GF_USE_SYSLOG
+/**
+ * gf_get_error_message -function to get error message for given error code
+ * @error_code: error code defined by log book
+ *
+ * @return: success: string
+ *          failure: NULL
+ */
+const char *
+gf_get_error_message (int error_code) {
+        return _gf_get_message (error_code);
+}
+
+
+/**
+ * gf_openlog -function to open syslog specific to gluster based on
+ *             existent of file /var/lib/glusterd/logger.conf
+ * @ident:    optional identification string similar to openlog()
+ * @option:   optional value to option to openlog().  Passing -1 uses
+ *            'LOG_PID | LOG_NDELAY' as default
+ * @facility: optional facility code similar to openlog().  Passing -1
+ *            uses LOG_DAEMON as default
+ *
+ * @return: void
+ */
+void
+gf_openlog (const char *ident, int option, int facility)
+{
+        int _option = option;
+        int _facility = facility;
+
+        if (-1 == _option) {
+                _option = LOG_PID | LOG_NDELAY;
+        }
+        if (-1 == _facility) {
+                _facility = LOG_LOCAL1;
+        }
+
+        setlocale(LC_ALL, "");
+        bindtextdomain("gluster", "/usr/share/locale");
+        textdomain("gluster");
+
+        openlog(ident, _option, _facility);
+}
+
+
+/**
+ * _json_escape -function to convert string to json encoded string
+ * @str: input string
+ * @buf: buffer to store encoded string
+ * @len: length of @buf
+ *
+ * @return: success: last unprocessed character position by pointer in @str
+ *          failure: NULL
+ *
+ * Internal function. Heavily inspired by _ul_str_escape() function in
+ * libumberlog
+ *
+ * Sample output:
+ * [1] str = "devel error"
+ *     buf = "devel error"
+ * [2] str = "devel	error"
+ *     buf = "devel\terror"
+ * [3] str = "I/O error on "/tmp/foo" file"
+ *     buf = "I/O error on \"/tmp/foo\" file"
+ * [4] str = "I/O erroron /tmp/bar file"
+ *     buf = "I/O error\u001bon /tmp/bar file"
+ *
+ */
+char *
+_json_escape(const char *str, char *buf, size_t len)
+{
+        static const unsigned char json_exceptions[UCHAR_MAX + 1] =
+                {
+                        [0x01] = 1, [0x02] = 1, [0x03] = 1, [0x04] = 1,
+                        [0x05] = 1, [0x06] = 1, [0x07] = 1, [0x08] = 1,
+                        [0x09] = 1, [0x0a] = 1, [0x0b] = 1, [0x0c] = 1,
+                        [0x0d] = 1, [0x0e] = 1, [0x0f] = 1, [0x10] = 1,
+                        [0x11] = 1, [0x12] = 1, [0x13] = 1, [0x14] = 1,
+                        [0x15] = 1, [0x16] = 1, [0x17] = 1, [0x18] = 1,
+                        [0x19] = 1, [0x1a] = 1, [0x1b] = 1, [0x1c] = 1,
+                        [0x1d] = 1, [0x1e] = 1, [0x1f] = 1,
+                        ['\\'] = 1, ['"'] = 1
+                };
+        static const char  json_hex_chars[16] = "0123456789abcdef";
+        unsigned char     *p = NULL;
+        size_t             pos = 0;
+
+        if (!str || !buf || len <= 0) {
+                return NULL;
+        }
+
+        for (p = (unsigned char *)str;
+             *p && (pos + 1) < len;
+             p++)
+        {
+                if (json_exceptions[*p] == 0) {
+                        buf[pos++] = *p;
+                        continue;
+                }
+
+                if ((pos + 2) >= len) {
+                        break;
+                }
+
+                switch (*p)
+                {
+                case '\b':
+                        buf[pos++] = '\\';
+                        buf[pos++] = 'b';
+                        break;
+                case '\n':
+                        buf[pos++] = '\\';
+                        buf[pos++] = 'n';
+                        break;
+                case '\r':
+                        buf[pos++] = '\\';
+                        buf[pos++] = 'r';
+                        break;
+                case '\t':
+                        buf[pos++] = '\\';
+                        buf[pos++] = 't';
+                        break;
+                case '\\':
+                        buf[pos++] = '\\';
+                        buf[pos++] = '\\';
+                        break;
+                case '"':
+                        buf[pos++] = '\\';
+                        buf[pos++] = '"';
+                        break;
+                default:
+                        if ((pos + 6) >= len) {
+                                buf[pos] = '\0';
+                                return (char *)p;
+                        }
+                        buf[pos++] = '\\';
+                        buf[pos++] = 'u';
+                        buf[pos++] = '0';
+                        buf[pos++] = '0';
+                        buf[pos++] = json_hex_chars[(*p) >> 4];
+                        buf[pos++] = json_hex_chars[(*p) & 0xf];
+                        break;
+                }
+        }
+
+        buf[pos] = '\0';
+        return (char *)p;
+}
+
+
+/**
+ * gf_syslog -function to submit message to syslog specific to gluster
+ * @error_code:        error code defined by log book
+ * @facility_priority: facility_priority of syslog()
+ * @format:            optional format string to syslog()
+ *
+ * @return: void
+ */
+void
+gf_syslog (int error_code, int facility_priority, char *format, ...)
+{
+        char       *msg = NULL;
+        char        json_msg[GF_JSON_MSG_LENGTH];
+        char       *p = NULL;
+        const char *error_message = NULL;
+        char        json_error_message[GF_JSON_MSG_LENGTH];
+        va_list     ap;
+
+        error_message = gf_get_error_message (error_code);
+
+        va_start (ap, format);
+        if (format) {
+                vasprintf (&msg, format, ap);
+                p = _json_escape (msg, json_msg, GF_JSON_MSG_LENGTH);
+                if (error_message) {
+                        p = _json_escape (error_message, json_error_message,
+                                          GF_JSON_MSG_LENGTH);
+                        syslog (facility_priority, GF_SYSLOG_CEE_FORMAT,
+                                json_msg, error_code, json_error_message);
+                } else {
+                        /* ignore the error code because no error message for it
+                           and use normal syslog */
+                        syslog (facility_priority, "%s", msg);
+                }
+                free (msg);
+        } else {
+                if (error_message) {
+                        /* no user message: treat error_message as msg */
+                        syslog (facility_priority, GF_SYSLOG_CEE_FORMAT,
+                                json_error_message, error_code,
+                                json_error_message);
+                } else {
+                        /* cannot produce log as neither error_message nor
+                           msg available */
+                }
+        }
+        va_end (ap);
+}
+#endif /* GF_USE_SYSLOG */
+
 void
 gf_log_globals_init (void *data)
 {