lvm update: Check for the CAP_SYS_ADMIN capability.

Fixes: #2426

diff --git a/src/lvm.c b/src/lvm.c
index 6310727..4bb1c34 100644 (file)
--- a/src/lvm.c
+++ b/src/lvm.c
@@ -21,13 +21,17 @@
  *   Benjamin Gilbert <bgilbert at backtick.net>
  **/
 
-#include <lvm2app.h>
-
 #include "collectd.h"
 
 #include "common.h"
 #include "plugin.h"
 
+#include <lvm2app.h>
+
+#ifdef HAVE_SYS_CAPABILITY_H
+#include <sys/capability.h>
+#endif /* HAVE_SYS_CAPABILITY_H */
+
 #define NO_VALUE UINT64_MAX
 #define PERCENT_SCALE_FACTOR 1e-8
 
@@ -183,6 +187,24 @@ static int lvm_read(void) {
   return 0;
 } /*lvm_read */
 
+static int lvm_init(void) {
+#if defined(HAVE_SYS_CAPABILITY_H) && defined(CAP_SYS_ADMIN)
+  if (check_capability(CAP_SYS_ADMIN) != 0) {
+    if (getuid() == 0)
+      WARNING("smart plugin: Running collectd as root, but the "
+              "CAP_SYS_ADMIN capability is missing. The plugin's read "
+              "function will probably fail. Is your init system dropping "
+              "capabilities?");
+    else
+      WARNING("smart plugin: collectd doesn't have the CAP_SYS_ADMIN "
+              "capability. If you don't want to run collectd as root, try "
+              "running \"setcap cap_sys_admin=ep\" on the collectd binary.");
+  }
+#endif
+  return 0;
+}
+
 void module_register(void) {
+  plugin_register_init("lvm", lvm_init);
   plugin_register_read("lvm", lvm_read);
 } /* void module_register */