Address review comments:

[collectd.git] / src / daemon / meta_data.c

diff --git a/src/daemon/meta_data.c b/src/daemon/meta_data.c
index b3f892a..d26570e 100644 (file)
--- a/src/daemon/meta_data.c
+++ b/src/daemon/meta_data.c
@@ -25,10 +25,12 @@
  **/
 
 #include "collectd.h"
+
+#include "common.h"
 #include "plugin.h"
 #include "meta_data.h"
 
-#include <pthread.h>
+#define MD_MAX_NONSTRING_CHARS 128
 
 /*
  * Data types
@@ -285,6 +287,17 @@ static meta_entry_t *md_entry_lookup (meta_data_t *md, /* {{{ */
 } /* }}} meta_entry_t *md_entry_lookup */
 
 /*
+ * Each value_list_t*, as it is going through the system, is handled by exactly
+ * one thread. Plugins which pass a value_list_t* to another thread, e.g. the
+ * rrdtool plugin, must create a copy first. The meta data within a
+ * value_list_t* is not thread safe and doesn't need to be.
+ *
+ * The meta data associated with cache entries are a different story. There, we
+ * need to ensure exclusive locking to prevent leaks and other funky business.
+ * This is ensured by the uc_meta_data_get_*() functions.
+ */
+
+/*
  * Public functions
  */
 meta_data_t *meta_data_create (void) /* {{{ */
@@ -323,8 +336,6 @@ meta_data_t *meta_data_clone (meta_data_t *orig) /* {{{ */
 
 int meta_data_clone_merge (meta_data_t **dest, meta_data_t *orig) /* {{{ */
 {
-  meta_entry_t *e;
-
   if (orig == NULL)
     return (0);
 
@@ -334,7 +345,7 @@ int meta_data_clone_merge (meta_data_t **dest, meta_data_t *orig) /* {{{ */
   }
 
   pthread_mutex_lock (&orig->lock);
-  for (e=orig->head; e != NULL; e = e->next)
+  for (meta_entry_t *e=orig->head; e != NULL; e = e->next)
   {
     md_entry_insert_clone((*dest), e);
   }
@@ -355,14 +366,12 @@ void meta_data_destroy (meta_data_t *md) /* {{{ */
 
 int meta_data_exists (meta_data_t *md, const char *key) /* {{{ */
 {
-  meta_entry_t *e;
-
   if ((md == NULL) || (key == NULL))
     return (-EINVAL);
 
   pthread_mutex_lock (&md->lock);
 
-  for (e = md->head; e != NULL; e = e->next)
+  for (meta_entry_t *e = md->head; e != NULL; e = e->next)
   {
     if (strcasecmp (key, e->key) == 0)
     {
@@ -377,14 +386,12 @@ int meta_data_exists (meta_data_t *md, const char *key) /* {{{ */
 
 int meta_data_type (meta_data_t *md, const char *key) /* {{{ */
 {
-  meta_entry_t *e;
-
   if ((md == NULL) || (key == NULL))
     return -EINVAL;
 
   pthread_mutex_lock (&md->lock);
 
-  for (e = md->head; e != NULL; e = e->next)
+  for (meta_entry_t *e = md->head; e != NULL; e = e->next)
   {
     if (strcasecmp (key, e->key) == 0)
     {
@@ -400,14 +407,13 @@ int meta_data_type (meta_data_t *md, const char *key) /* {{{ */
 int meta_data_toc (meta_data_t *md, char ***toc) /* {{{ */
 {
   int i = 0, count = 0;
-  meta_entry_t *e;
 
   if ((md == NULL) || (toc == NULL))
     return -EINVAL;
 
   pthread_mutex_lock (&md->lock);
 
-  for (e = md->head; e != NULL; e = e->next)
+  for (meta_entry_t *e = md->head; e != NULL; e = e->next)
     ++count;
 
   if (count == 0)
@@ -417,7 +423,7 @@ int meta_data_toc (meta_data_t *md, char ***toc) /* {{{ */
   }
 
   *toc = calloc(count, sizeof(**toc));
-  for (e = md->head; e != NULL; e = e->next)
+  for (meta_entry_t *e = md->head; e != NULL; e = e->next)
     (*toc)[i++] = strdup(e->key);
 
   pthread_mutex_unlock (&md->lock);
@@ -726,4 +732,66 @@ int meta_data_get_boolean (meta_data_t *md, /* {{{ */
   return (0);
 } /* }}} int meta_data_get_boolean */
 
+int meta_data_as_string (meta_data_t *md, /* {{{ */
+    const char *key, char **value)
+{
+  meta_entry_t *e;
+  char *actual;
+  char buffer[MD_MAX_NONSTRING_CHARS];  /* For non-string types. */
+  char *temp;
+
+  if ((md == NULL) || (key == NULL) || (value == NULL))
+    return (-EINVAL);
+
+  pthread_mutex_lock (&md->lock);
+
+  e = md_entry_lookup (md, key);
+  if (e == NULL)
+  {
+    pthread_mutex_unlock (&md->lock);
+    return (-ENOENT);
+  }
+
+  switch (e->type)
+  {
+    case MD_TYPE_STRING:
+      actual = e->value.mv_string;
+      break;
+    case MD_TYPE_SIGNED_INT:
+      ssnprintf (buffer, sizeof (buffer), "%"PRIi64, e->value.mv_signed_int);
+      actual = buffer;
+      break;
+    case MD_TYPE_UNSIGNED_INT:
+      ssnprintf (buffer, sizeof (buffer), "%"PRIu64, e->value.mv_unsigned_int);
+      actual = buffer;
+      break;
+    case MD_TYPE_DOUBLE:
+      ssnprintf (buffer, sizeof (buffer), GAUGE_FORMAT, e->value.mv_double);
+      actual = buffer;
+      break;
+    case MD_TYPE_BOOLEAN:
+      actual = e->value.mv_boolean ? "true" : "false";
+      break;
+    default:
+      pthread_mutex_unlock (&md->lock);
+      ERROR ("meta_data_as_string: unknown type %d for key `%s'",
+          e->type, e->key);
+      return (-ENOENT);
+  }
+
+  temp = md_strdup (actual);
+  if (temp == NULL)
+  {
+    pthread_mutex_unlock (&md->lock);
+    ERROR ("meta_data_as_string: md_strdup failed for key `%s'.", e->key);
+    return (-ENOMEM);
+  }
+
+  pthread_mutex_unlock (&md->lock);
+
+  *value = temp;
+
+  return (0);
+} /* }}} int meta_data_as_string */
+
 /* vim: set sw=2 sts=2 et fdm=marker : */