X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Fdaemon%2Fmeta_data.c;h=9e4fd07ecfdf99716a11e64532a8ccb6d5654041;hb=5523a080010dcb7a61dc0dccc3969a2a048e52f9;hp=f87e35e41c78607d1eb3609688d6982c02d341c8;hpb=3dc0454f7bee3e852171d1f6944891693364ee01;p=collectd.git

diff --git a/src/daemon/meta_data.c b/src/daemon/meta_data.c
index f87e35e4..9e4fd07e 100644
--- a/src/daemon/meta_data.c
+++ b/src/daemon/meta_data.c
@@ -25,11 +25,10 @@
  **/
 
 #include "collectd.h"
+
 #include "plugin.h"
 #include "meta_data.h"
 
-#include <pthread.h>
-
 /*
  * Data types
  */
@@ -105,12 +104,15 @@ static meta_entry_t *md_entry_alloc (const char *key) /* {{{ */
   return (e);
 } /* }}} meta_entry_t *md_entry_alloc */
 
-static meta_entry_t *md_entry_clone (const meta_entry_t *orig) /* {{{ */
+/* XXX: The lock on md must be held while calling this function! */
+static meta_entry_t *md_entry_clone_contents (const meta_entry_t *orig) /* {{{ */
 {
   meta_entry_t *copy;
 
-  if (orig == NULL)
-    return (NULL);
+  /* WARNINGS :
+   *  - we do not check that orig != NULL here. You should have done it before.
+   *  - we do not set copy->next. DO NOT FORGET TO SET copy->next IN YOUR FUNCTION
+   */
 
   copy = md_entry_alloc (orig->key);
   if (copy == NULL)
@@ -121,6 +123,18 @@ static meta_entry_t *md_entry_clone (const meta_entry_t *orig) /* {{{ */
   else
     copy->value = orig->value;
 
+  return (copy);
+} /* }}} meta_entry_t *md_entry_clone_contents */
+
+static meta_entry_t *md_entry_clone (const meta_entry_t *orig) /* {{{ */
+{
+  meta_entry_t *copy;
+
+  if (orig == NULL)
+    return (NULL);
+
+  copy = md_entry_clone_contents(orig);
+
   copy->next = md_entry_clone (orig->next);
   return (copy);
 } /* }}} meta_entry_t *md_entry_clone */
@@ -197,6 +211,63 @@ static int md_entry_insert (meta_data_t *md, meta_entry_t *e) /* {{{ */
 } /* }}} int md_entry_insert */
 
 /* XXX: The lock on md must be held while calling this function! */
+static int md_entry_insert_clone (meta_data_t *md, meta_entry_t *orig) /* {{{ */
+{
+  meta_entry_t *e;
+  meta_entry_t *this;
+  meta_entry_t *prev;
+
+  /* WARNINGS :
+   *  - we do not check that md and e != NULL here. You should have done it before.
+   *  - we do not use the lock. You should have set it before.
+   */
+
+  e = md_entry_clone_contents(orig);
+
+  prev = NULL;
+  this = md->head;
+  while (this != NULL)
+  {
+    if (strcasecmp (e->key, this->key) == 0)
+      break;
+
+    prev = this;
+    this = this->next;
+  }
+
+  if (this == NULL)
+  {
+    /* This key does not exist yet. */
+    if (md->head == NULL)
+      md->head = e;
+    else
+    {
+      assert (prev != NULL);
+      prev->next = e;
+    }
+
+    e->next = NULL;
+  }
+  else /* (this != NULL) */
+  {
+    if (prev == NULL)
+      md->head = e;
+    else
+      prev->next = e;
+
+    e->next = this->next;
+  }
+
+  if (this != NULL)
+  {
+    this->next = NULL;
+    md_entry_free (this);
+  }
+
+  return (0);
+} /* }}} int md_entry_insert_clone */
+
+/* XXX: The lock on md must be held while calling this function! */
 static meta_entry_t *md_entry_lookup (meta_data_t *md, /* {{{ */
     const char *key)
 {
@@ -213,6 +284,17 @@ 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) /* {{{ */
@@ -249,6 +331,26 @@ meta_data_t *meta_data_clone (meta_data_t *orig) /* {{{ */
   return (copy);
 } /* }}} meta_data_t *meta_data_clone */
 
+int meta_data_clone_merge (meta_data_t **dest, meta_data_t *orig) /* {{{ */
+{
+  if (orig == NULL)
+    return (0);
+
+  if (*dest == NULL) {
+    *dest = meta_data_clone(orig);
+    return(0);
+  }
+
+  pthread_mutex_lock (&orig->lock);
+  for (meta_entry_t *e=orig->head; e != NULL; e = e->next)
+  {
+    md_entry_insert_clone((*dest), e);
+  }
+  pthread_mutex_unlock (&orig->lock);
+
+  return (0);
+} /* }}} int meta_data_clone_merge */
+
 void meta_data_destroy (meta_data_t *md) /* {{{ */
 {
   if (md == NULL)
@@ -261,14 +363,12 @@ 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)
     {
@@ -283,14 +383,12 @@ 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)
     {
@@ -306,14 +404,13 @@ 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)
@@ -323,7 +420,7 @@ 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);