log: Add support for journal logging

This logging is available if the software was build with the configure
option --with-systemd-journal.

It will be enabled by default if libsystemd is found.

The runtime parameter --log-journal enables to output of log messages
to the systemd journal.

Please note that the journal priority field has the same value as the
syslog level so no conversion is required here.

configure.ac

@@ -242,6 +242,40 @@ esac
 
 AM_CONDITIONAL(SUSPEND_RESUME_SYSTEMD, test "x$with_suspend_resume" = "xsystemd")
 
+dnl-----------------------------------------------------------------------------
+dnl systemd journal support
+dnl
+
+AC_ARG_WITH(systemd-journal,
+            AS_HELP_STRING([--with-systemd-journal=no|yes|auto],
+                           [Enable systemd journal support [[default=auto]]]),,
+            [with_systemd_journal=auto])
+
+if test "x$with_systemd_journal" = "xauto"; then
+    if test "x$have_libsystemd" = "xyes"; then
+        with_systemd_journal=yes
+    else
+        with_systemd_journal=no
+    fi
+fi
+
+case $with_systemd_journal in
+    no)
+        AC_DEFINE(WITH_SYSTEMD_JOURNAL, 0, [Define if you want systemd journal support])
+        ;;
+    yes)
+        if test "x$have_libsystemd" = "xno"; then
+            AC_MSG_ERROR(libsystemd development headers are required)
+	fi
+        AC_DEFINE(WITH_SYSTEMD_JOURNAL, 1, [Define if you want systemd journal support])
+        ;;
+    *)
+        AC_MSG_ERROR([Wrong value for --with-systemd-journal: $with_systemd_journal])
+        ;;
+esac
+
+AM_CONDITIONAL(WITH_SYSTEMD_JOURNAL, test "x$with_systemd_journal" = "xyes")
+
 dnl-----------------------------------------------------------------------------
 dnl PolicyKit
 dnl
@@ -425,6 +459,7 @@ echo "
       mbim support:            ${with_mbim}
       qmi support:             ${with_qmi}
       suspend/resume support:  ${with_suspend_resume}
+      systemd journal support: ${with_systemd_journal}
 
     Miscellaneous:
       gobject introspection:   ${found_introspection}

docs/man/ModemManager.8

@@ -50,6 +50,9 @@ messages are logged. Given level must be one of "ERR", "WARN", "INFO" or "DEBUG"
 Specify location of the file where ModemManager will dump its log messages,
 instead of syslog.
 .TP
+.B \-\-log\-journal
+Output log message to the systemd journal.
+.TP
 .B \-\-log\-timestamps
 Include absolute timestamps in the log output.
 .TP

src/Makefile.am

@@ -46,6 +46,11 @@ AM_CFLAGS  += $(POLKIT_CFLAGS)
 AM_LDFLAGS += $(POLKIT_LIBS)
 endif
 
+if WITH_SYSTEMD_JOURNAL
+AM_CFLAGS += $(LIBSYSTEMD_CFLAGS)
+AM_LDFLAGS += $(LIBSYSTEMD_LIBS)
+endif
+
 ################################################################################
 # generic udev rules
 ################################################################################

src/main.c

@@ -141,6 +141,7 @@ main (int argc, char *argv[])
 
     if (!mm_log_setup (mm_context_get_log_level (),
                        mm_context_get_log_file (),
+                       mm_context_get_log_journal (),
                        mm_context_get_log_timestamps (),
                        mm_context_get_log_relative_timestamps (),
                        &err)) {

src/mm-context.c

@@ -89,6 +89,7 @@ mm_context_get_no_auto_scan (void)
 
 static const gchar *log_level;
 static const gchar *log_file;
+static gboolean     log_journal;
 static gboolean     log_show_ts;
 static gboolean     log_rel_ts;
 
@@ -103,6 +104,13 @@ static const GOptionEntry log_entries[] = {
         "Path to log file",
         "[PATH]"
     },
+#if WITH_SYSTEMD_JOURNAL
+    {
+        "log-journal", 0, 0, G_OPTION_ARG_NONE, &log_journal,
+        "Log to systemd journal",
+        NULL
+    },
+#endif
     {
         "log-timestamps", 0, 0, G_OPTION_ARG_NONE, &log_show_ts,
         "Show timestamps in log output",
@@ -142,6 +150,12 @@ mm_context_get_log_file (void)
     return log_file;
 }
 
+gboolean
+mm_context_get_log_journal (void)
+{
+    return log_journal;
+}
+
 gboolean
 mm_context_get_log_timestamps (void)
 {

src/mm-context.h

@@ -33,6 +33,7 @@ gboolean     mm_context_get_no_auto_scan          (void);
 /* Logging support */
 const gchar *mm_context_get_log_level               (void);
 const gchar *mm_context_get_log_file                (void);
+gboolean     mm_context_get_log_journal             (void);
 gboolean     mm_context_get_log_timestamps          (void);
 gboolean     mm_context_get_log_relative_timestamps (void);
 

src/mm-log.c

@@ -35,6 +35,11 @@
 #include <libmbim-glib.h>
 #endif
 
+#if defined WITH_SYSTEMD_JOURNAL
+#define SD_JOURNAL_SUPPRESS_LOCATION
+#include <systemd/sd-journal.h>
+#endif
+
 #include "mm-log.h"
 
 enum {
@@ -148,6 +153,43 @@ log_backend_syslog (const char *loc,
     syslog (syslog_level, "%s", message);
 }
 
+#if defined WITH_SYSTEMD_JOURNAL
+static void
+log_backend_systemd_journal (const char *loc,
+                             const char *func,
+                             int syslog_level,
+                             const char *message,
+                             size_t length)
+{
+    const char *line;
+    size_t file_length;
+
+    if (loc == NULL) {
+        sd_journal_send ("MESSAGE=%s", message,
+                         "PRIORITY=%d", syslog_level,
+                         NULL);
+        return;
+    }
+
+    line = strstr (loc, ":");
+    if (line) {
+        file_length = line - loc;
+        line++;
+    } else {
+        /* This is not supposed to happen but we must be prepared for this */
+        line = loc;
+        file_length = 0;
+    }
+
+    sd_journal_send ("MESSAGE=%s", message,
+                     "PRIORITY=%d", syslog_level,
+                     "CODE_FUNC=%s", func,
+                     "CODE_FILE=%.*s", file_length, loc,
+                     "CODE_LINE=%s", line,
+                     NULL);
+}
+#endif
+
 void
 _mm_log (const char *loc,
          const char *func,
@@ -242,6 +284,7 @@ mm_log_set_level (const char *level, GError **error)
 gboolean
 mm_log_setup (const char *level,
               const char *log_file,
+              gboolean log_journal,
               gboolean show_timestamps,
               gboolean rel_timestamps,
               GError **error)
@@ -258,6 +301,12 @@ mm_log_setup (const char *level,
     /* Grab start time for relative timestamps */
     g_get_current_time (&rel_start);
 
+#if defined WITH_SYSTEMD_JOURNAL
+    if (log_journal) {
+        log_backend = log_backend_systemd_journal;
+        append_log_level_text = FALSE;
+    } else
+#endif
     if (log_file == NULL) {
         openlog (G_LOG_DOMAIN, LOG_CONS | LOG_PID | LOG_PERROR, LOG_DAEMON);
         log_backend = log_backend_syslog;

src/mm-log.h

@@ -51,6 +51,7 @@ gboolean mm_log_set_level (const char *level, GError **error);
 
 gboolean mm_log_setup (const char *level,
                        const char *log_file,
+                       gboolean log_journal,
                        gboolean show_ts,
                        gboolean rel_ts,
                        GError **error);