Bug 967871 - net-snmp does not display correct lm_sensors sensor data / missing CPU cores

commit e886f5eb9701851ad6948583156bfd59fcb6110f
Author: Jan Safranek <jsafranek@users.sourceforge.net>
Date:   Wed Feb 25 09:30:24 2015 +0100

    CHANGES: snmpd: fixed lm_sensors not reporting sensors with duplicate names.
    
    Some systems report two or more sensors with the same name.
    This patch adds support for reporting of all these duplicate
    sensor names.
    
    Before the patch, these sensors were reported:
    > lmTempSensorsDevice.2 = STRING: Core 0
    
    After the patch, new sensors appear with a prefix:
    > lmTempSensorsDevice.2 = STRING: Core 0
    > lmTempSensorsDevice.6 = STRING: coretemp-isa-0004:Core 0
    
    This approach keeps backward compatibility (applications used to 'Core 0'
    will keep workig, while it adds new sensorscto the table (with a prefix).

diff --git a/agent/mibgroup/hardware/sensors/lmsensors_v3.c b/agent/mibgroup/hardware/sensors/lmsensors_v3.c
index 60af9e6..1de7c68 100644
--- a/agent/mibgroup/hardware/sensors/lmsensors_v3.c
+++ b/agent/mibgroup/hardware/sensors/lmsensors_v3.c
@@ -86,7 +86,28 @@ netsnmp_sensor_arch_load(netsnmp_cache *cache, void *vp) {
                  *  (inserting it in the appropriate sub-containers)
                  */
                 sp = sensor_by_name( label, type );
-                if ( sp ) {
+                if ( sp && sp->flags & NETSNMP_SENSOR_FLAG_ACTIVE) {
+                    /*
+                     * Some HW does not have unique sensors labels.
+                     * We already have a sensor with this label, thus
+                     * try to create unique label by adding chip-name prefix
+                     * and try again.
+                     */
+                    char chip_name[64];
+                    char new_label[128];
+                    int ret;
+                    DEBUGMSGTL(("sensors:arch:detail", "Already know label %s, adding prefix\n", label));
+                    ret = sensors_snprintf_chip_name(chip_name, sizeof(chip_name), chip);
+                    if (ret < 0) {
+                        DEBUGMSGTL(("sensors:arch:detail", "Can't get chip name for label %s\n", label));
+                        free(label);
+                        continue;
+                    }
+                    snprintf(new_label, sizeof(new_label), "%s:%s", chip_name, label);
+                    DEBUGMSGTL(("sensors:arch:detail", "New label: %s\n", new_label));
+                    sp = sensor_by_name( new_label, type );
+                }
+                if (sp) {
                     sp->value = val;
                     sp->flags|= NETSNMP_SENSOR_FLAG_ACTIVE;
                 }