paraslash 0.7.3

[paraslash.git] / daemon.c

diff --git a/daemon.c b/daemon.c
index ddfe680cebc63dc1c7af89fde333c665873765eb..d8f598bef0c2eb1709fa46169c314e17a212d7b8 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -31,6 +31,12 @@ struct daemon {
        /** Used for colored log messages. */
        char log_colors[NUM_LOGLEVELS][COLOR_MAXLEN];
        char *old_cwd;
+       /*
+        * If these pointers are non-NULL, the functions are called from
+        * daemon_log() before and after writing each log message.
+        */
+       void (*pre_log_hook)(void);
+       void (*post_log_hook)(void);
 };
 
 static struct daemon the_daemon, *me = &the_daemon;
@@ -52,24 +58,30 @@ static void daemon_set_default_log_colors(void)
 }
 
 /**
- * Set the color for one loglevel.
+ * Set the color for log messages of the given severity level.
  *
- * \param arg Must be of the form "ll:[fg [bg]] [attr]".
+ * \param arg Must be of the form "severity:[fg [bg]] [attr]".
  */
 void daemon_set_log_color_or_die(const char *arg)
 {
+       unsigned ll;
+       const char * const sev[] = {SEVERITIES};
        char *p = strchr(arg, ':');
-       int ret, ll;
 
        if (!p)
                goto err;
-       ret = get_loglevel_by_name(arg);
-       if (ret < 0)
-               goto err;
-       ll = ret;
-       p++;
-       color_parse_or_die(p, me->log_colors[ll]);
-       return;
+       for (ll = 0; ll < NUM_LOGLEVELS; ll++) {
+               const char *name = sev[ll];
+               /*
+                * Parse only the first part of the string so that, for
+                * example, the argument "info:something_else" is recognized.
+                * Note that the string comparison is performed
+                * case-insensitively.
+                */
+               if (strncasecmp(arg, name, strlen(name)))
+                       continue;
+               return color_parse_or_die(p + 1, me->log_colors[ll]);
+       }
 err:
        PARA_EMERG_LOG("%s: invalid color argument\n", arg);
        exit(EXIT_FAILURE);
@@ -128,16 +140,51 @@ void daemon_set_logfile(const char *logfile_name)
 }
 
 /**
- * Suppress log messages with severity lower than the given loglevel.
+ * Control the verbosity for logging.
+ *
+ * This instructs the daemon to not log subsequent messages whose severity is
+ * lower than the given value.
+ *
+ * \param loglevel The new log level.
+ */
+void daemon_set_loglevel(int loglevel)
+{
+       assert(loglevel >= 0);
+       assert(loglevel < NUM_LOGLEVELS);
+       me->loglevel = loglevel;
+}
+
+/**
+ * Get the current log level of the daemon.
  *
- * \param loglevel The smallest level that should be logged.
+ * \return Greater or equal than zero and less than NUM_LOGLEVELS. This
+ * function never fails.
  */
-void daemon_set_loglevel(const char *loglevel)
+int daemon_get_loglevel(void)
 {
-       int ret = get_loglevel_by_name(loglevel);
+       return me->loglevel;
+}
 
-       assert(ret >= 0);
-       me->loglevel = ret;
+/**
+ * Register functions to be called before and after a message is logged.
+ *
+ * \param pre_log_hook Called before the message is logged.
+ * \param post_log_hook Called after the message is logged.
+ *
+ * The purpose of this function is to provide a primitive for multi-threaded
+ * applications to serialize the access to the log facility, preventing
+ * interleaving log messages. This can be achieved by having the pre-log hook
+ * acquire a lock which blocks the other threads on the attempt to log a
+ * message at the same time.  The post-log hook is responsible for releasing
+ * the lock.
+ *
+ * If these hooks are unnecessary, for example because the application is
+ * single-threaded, this function does not need to be called.
+ */
+void daemon_set_hooks(void (*pre_log_hook)(void), void (*post_log_hook)(void))
+{
+       me->pre_log_hook = pre_log_hook;
+       me->post_log_hook = post_log_hook;
 }
 
 /**
@@ -235,9 +282,9 @@ void daemon_close_log(void)
 }
 
 /**
- * fopen() the logfile in append mode.
+ * Open the logfile in append mode.
  *
- * \return Either succeeds or exits.
+ * This function either succeeds or exits.
  */
 void daemon_open_log_or_die(void)
 {
@@ -409,6 +456,8 @@ __printf_2_3 void daemon_log(int ll, const char* fmt,...)
                return;
 
        fp = me->logfile? me->logfile : stderr;
+       if (me->pre_log_hook)
+               me->pre_log_hook();
        color = daemon_test_flag(DF_COLOR_LOG)? me->log_colors[ll] : NULL;
        if (color)
                fprintf(fp, "%s", color);
@@ -441,4 +490,6 @@ __printf_2_3 void daemon_log(int ll, const char* fmt,...)
        va_end(argp);
        if (color)
                fprintf(fp, "%s", COLOR_RESET);
+       if (me->post_log_hook)
+               me->post_log_hook();
 }