check and warn about capabilities misconfiguration

[collectd.git] / src / iptables.c

diff --git a/src/iptables.c b/src/iptables.c
index 7ff59c1..a2ed4c7 100644 (file)
--- a/src/iptables.c
+++ b/src/iptables.c
@@ -30,6 +30,10 @@
 #include "plugin.h"
 #include "configfile.h"
 
+#ifdef HAVE_SYS_CAPABILITY_H
+# include <sys/capability.h>
+#endif
+
 #include <libiptc/libiptc.h>
 #include <libiptc/libip6tc.h>
 
@@ -420,12 +424,11 @@ static void submit_chain (iptc_handle_t *handle, ip_chain_t *chain)
 
 static int iptables_read (void)
 {
-    int i;
     int num_failures = 0;
     ip_chain_t *chain;
 
     /* Init the iptc handle structure and query the correct table */
-    for (i = 0; i < chain_num; i++)
+    for (int i = 0; i < chain_num; i++)
     {
         chain = chain_list[i];
 
@@ -489,9 +492,7 @@ static int iptables_read (void)
 
 static int iptables_shutdown (void)
 {
-    int i;
-
-    for (i = 0; i < chain_num; i++)
+    for (int i = 0; i < chain_num; i++)
     {
         if ((chain_list[i] != NULL) && (chain_list[i]->rule_type == RTYPE_COMMENT))
             sfree (chain_list[i]->rule.comment);
@@ -502,10 +503,30 @@ static int iptables_shutdown (void)
     return (0);
 } /* int iptables_shutdown */
 
+static int iptables_init (void)
+{
+#ifdef HAVE_SYS_CAPABILITY_H
+    if (check_capability (CAP_NET_ADMIN) != 0)
+    {
+        if (getuid () == 0)
+            WARNING ("iptables plugin: Running collectd as root, but the "
+                  "CAP_NET_ADMIN capability is missing. The plugin's read "
+                  "function will probably fail. Is your init system dropping "
+                  "capabilities ?");
+        else
+            WARNING ("iptables plugin: collectd doesn't have the CAP_NET_ADMIN "
+                  "capability. If you don't want to run collectd as root, try "
+                  "running \"setcap cap_net_admin=ep\" on the collectd binary.");
+    }
+#endif
+    return (0);
+} /* int iptables_init */
+
 void module_register (void)
 {
     plugin_register_config ("iptables", iptables_config,
                              config_keys, config_keys_num);
+    plugin_register_init ("iptables", iptables_init);
     plugin_register_read ("iptables", iptables_read);
     plugin_register_shutdown ("iptables", iptables_shutdown);
 } /* void module_register */