disk: Add udev-based device renaming on Linux

[collectd.git] / src / disk.c

diff --git a/src/disk.c b/src/disk.c
index 36d0a0c..cdf2816 100644 (file)
--- a/src/disk.c
+++ b/src/disk.c
@@ -128,11 +128,19 @@ static int pnumdisk;
 # error "No applicable input method."
 #endif
 
+#if HAVE_LIBUDEV
+#include <libudev.h>
+
+static char *conf_udev_name_attr = NULL;
+static struct udev *handle_udev;
+#endif
+
 static const char *config_keys[] =
 {
        "Disk",
        "UseBSDName",
-       "IgnoreSelected"
+       "IgnoreSelected",
+       "UdevNameAttr"
 };
 static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
 
@@ -165,6 +173,21 @@ static int disk_config (const char *key, const char *value)
         "on Mach / Mac OS X and will be ignored.");
 #endif
   }
+  else if (strcasecmp ("UdevNameAttr", key) == 0)
+  {
+#if HAVE_LIBUDEV
+    if (conf_udev_name_attr != NULL)
+    {
+      free (conf_udev_name_attr);
+      conf_udev_name_attr = NULL;
+    }
+    if ((conf_udev_name_attr = strdup (value)) == NULL)
+      return (1);
+#else
+    WARNING ("disk plugin: The \"UdevNameAttr\" option is only supported "
+        "if collectd is built with libudev support");
+#endif
+  }
   else
   {
     return (-1);
@@ -259,6 +282,34 @@ static counter_t disk_calc_time_incr (counter_t delta_time, counter_t delta_ops)
 }
 #endif
 
+#if HAVE_LIBUDEV
+/**
+ * Attempt to provide an rename disk instance from an assigned udev attribute.
+ *
+ * On success, it returns a strduped char* to the desired attribute value.
+ * Otherwise it returns NULL.
+ */
+
+static char *disk_udev_attr_name (struct udev *udev, char *disk_name, const char *attr)
+{
+       struct udev_device *dev;
+       const char *prop;
+       char *output = NULL;
+
+       dev = udev_device_new_from_subsystem_sysname (udev, "block", disk_name);
+       if (dev != NULL)
+       {
+               prop = udev_device_get_property_value (dev, attr);
+               if (prop) {
+                       output = strdup (prop);
+                       DEBUG ("disk plugin: renaming %s => %s", disk_name, output);
+               }
+               udev_device_unref (dev);
+       }
+       return output;
+}
+#endif
+
 #if HAVE_IOKIT_IOKITLIB_H
 static signed long long dict_get_value (CFDictionaryRef dict, const char *key)
 {
@@ -505,9 +556,15 @@ static int disk_read (void)
                fieldshift = 1;
        }
 
+#if HAVE_LIBUDEV
+       handle_udev = udev_new();
+#endif
+
        while (fgets (buffer, sizeof (buffer), fh) != NULL)
        {
                char *disk_name;
+               char *output_name;
+               char *alt_name;
 
                numfields = strsplit (buffer, fields, 32);
 
@@ -659,25 +716,43 @@ static int disk_read (void)
                        continue;
                }
 
+               output_name = disk_name;
+
+#if HAVE_LIBUDEV
+               alt_name = disk_udev_attr_name (handle_udev, disk_name,
+                               conf_udev_name_attr);
+#else
+               alt_name = NULL;
+#endif
+               if (alt_name != NULL)
+                       output_name = alt_name;
+
                if ((ds->read_bytes != 0) || (ds->write_bytes != 0))
-                       disk_submit (disk_name, "disk_octets",
+                       disk_submit (output_name, "disk_octets",
                                        ds->read_bytes, ds->write_bytes);
 
                if ((ds->read_ops != 0) || (ds->write_ops != 0))
-                       disk_submit (disk_name, "disk_ops",
+                       disk_submit (output_name, "disk_ops",
                                        read_ops, write_ops);
 
                if ((ds->avg_read_time != 0) || (ds->avg_write_time != 0))
-                       disk_submit (disk_name, "disk_time",
+                       disk_submit (output_name, "disk_time",
                                        ds->avg_read_time, ds->avg_write_time);
 
                if (is_disk)
                {
-                       disk_submit (disk_name, "disk_merged",
+                       disk_submit (output_name, "disk_merged",
                                        read_merged, write_merged);
                } /* if (is_disk) */
+
+               /* release udev-based alternate name, if allocated */
+               free(alt_name);
        } /* while (fgets (buffer, sizeof (buffer), fh) != NULL) */
 
+#if HAVE_LIBUDEV
+       udev_unref(handle_udev);
+#endif
+
        fclose (fh);
 /* #endif defined(KERNEL_LINUX) */