debug: Add infrastructure for supporting multiple backends

Signed-off-by: Christof Schmitt <cs@samba.org>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>

diff --git a/lib/util/debug.c b/lib/util/debug.c
index 351a88c5c478e12262b6513e468f9977ca062d87..9eba5b823bd5ac4f68ae3abad6df60631082e99f 100644 (file)
--- a/lib/util/debug.c
+++ b/lib/util/debug.c
@@ -126,6 +126,152 @@ static int debug_level_to_priority(int level)
 }
 #endif
 
+/* -------------------------------------------------------------------------- **
+ * Debug backends. When logging to DEBUG_FILE, send the log entries to
+ * all active backends.
+ */
+
+static struct debug_backend {
+       const char *name;
+       int log_level;
+       int new_log_level;
+       void (*reload)(bool enabled, bool prev_enabled, const char *prog_name);
+       void (*log)(int msg_level, const char *msg, const char *msg_no_nl);
+} debug_backends[] = {
+};
+
+static struct debug_backend *debug_find_backend(const char *name)
+{
+       int i;
+
+       for (i = 0; i < ARRAY_SIZE(debug_backends); i++) {
+               if (strcmp(name, debug_backends[i].name) == 0) {
+                       return &debug_backends[i];
+               }
+       }
+
+       return NULL;
+}
+
+/*
+ * parse "backend[:option][@loglevel]
+ */
+static void debug_backend_parse_token(char *tok)
+{
+       char *backend_name_option, *backend_name,*backend_level, *saveptr;
+       struct debug_backend *b;
+
+       /*
+        * First parse into backend[:option] and loglevel
+        */
+       backend_name_option = strtok_r(tok, "@\0", &saveptr);
+       if (backend_name_option == NULL) {
+               return;
+       }
+
+       backend_level = strtok_r(NULL, "\0", &saveptr);
+
+       /*
+        * Now parse backend[:option]
+        */
+       backend_name = strtok_r(backend_name_option, ":\0", &saveptr);
+       if (backend_name == NULL) {
+               return;
+       }
+
+       /*
+        * No backend is using the option yet.
+        */
+#if 0
+       backend_option = strtok_r(NULL, "\0", &saveptr);
+#endif
+
+       /*
+        * Find and update backend
+        */
+       b = debug_find_backend(backend_name);
+       if (b == NULL) {
+               return;
+       }
+
+       if (backend_level == NULL) {
+               b->new_log_level = MAX_DEBUG_LEVEL;
+       } else {
+               b->new_log_level = atoi(backend_level);
+       }
+}
+
+/*
+ * parse "backend1[:option1][@loglevel1] backend2[option2][@loglevel2] ... "
+ * and enable/disable backends accordingly
+ */
+static void debug_set_backends(const char *param)
+{
+       size_t str_len = strlen(param);
+       char str[str_len+1];
+       char *tok, *saveptr;
+       int i;
+
+       /*
+        * initialize new_log_level to detect backends that have been
+        * disabled
+        */
+       for (i = 0; i < ARRAY_SIZE(debug_backends); i++) {
+               debug_backends[i].new_log_level = -1;
+       }
+
+       memcpy(str, param, str_len + 1);
+
+       tok = strtok_r(str, LIST_SEP, &saveptr);
+       if (tok == NULL) {
+               return;
+       }
+
+       while (tok != NULL) {
+               debug_backend_parse_token(tok);
+               tok = strtok_r(NULL, LIST_SEP, &saveptr);
+       }
+
+       /*
+        * Let backends react to config changes
+        */
+       for (i = 0; i < ARRAY_SIZE(debug_backends); i++) {
+               struct debug_backend *b = &debug_backends[i];
+
+               if (b->reload) {
+                       bool enabled = b->new_log_level > -1;
+                       bool previously_enabled = b->log_level > -1;
+
+                       b->reload(enabled, previously_enabled, state.prog_name);
+               }
+               b->log_level = b->new_log_level;
+       }
+}
+
+static void debug_backends_log(const char *msg, int msg_level)
+{
+       char msg_no_nl[FORMAT_BUFR_SIZE];
+       int i, len;
+
+       /*
+        * Some backends already add an extra newline, so also provide
+        * a buffer without the newline character.
+        */
+       len = MIN(strlen(msg), FORMAT_BUFR_SIZE - 1);
+       if (msg[len - 1] == '\n') {
+               len--;
+       }
+
+       memcpy(msg_no_nl, msg, len);
+       msg_no_nl[len] = '\0';
+
+       for (i = 0; i < ARRAY_SIZE(debug_backends); i++) {
+               if (msg_level <= debug_backends[i].log_level) {
+                       debug_backends[i].log(msg_level, msg, msg_no_nl);
+               }
+       }
+}
+
 /* -------------------------------------------------------------------------- **
  * External variables.
  */
@@ -464,6 +610,7 @@ Init debugging (one time stuff)
 
 static void debug_init(void)
 {
+       int i;
        const char **p;
 
        if (state.initialized)
@@ -476,6 +623,11 @@ static void debug_init(void)
        for(p = default_classname_table; *p; p++) {
                debug_add_class(*p);
        }
+
+       for (i = 0; i < ARRAY_SIZE(debug_backends); i++) {
+               debug_backends[i].log_level = -1;
+               debug_backends[i].new_log_level = -1;
+       }
 }
 
 /* This forces in some smb.conf derived values into the debug system.