[metrics] Changed the extension from cpp to cc.

- Fix date of CMakeLists.txt.
- Initialization of the used variables in the cpu usage calculation.

lib/include/srslte/system/sys_metrics.h

@@ -24,7 +24,7 @@
 
 namespace srslte {
 
-/// Metrics that will be returned in the system.
+/// Metrics of cpu usage, memory consumption and number of thread used by the process.
 struct sys_metrics_t {
   unsigned process_realmem_kB    = 0;
   unsigned process_virtualmem_kB = 0;

lib/include/srslte/system/sys_metrics_processor.h

@@ -35,12 +35,18 @@ class sys_metrics_processor
   struct proc_stats_info {
     proc_stats_info();
 
+    // Initialize the variables that will be used.
+    int long      num_threads = 0;
+    unsigned long utime       = 0;
+    unsigned long stime       = 0;
+
+    // Rest of the information of the stats file.
     int           pid, ppid, pgrp, session, tty_nr, tpgid, exit_signal, processor, exit_code;
     unsigned      flags, rt_priority, policy;
-    unsigned long minflt, cminflt, majflt, cmajflt, utime, stime, vsize, rsslim, startcode, endcode, startstack,
-        kstkesp, kstkeip, signal, blocked, sigignore, sigcatch, wchan, nswap, cnswap, guest_time, start_data, end_data,
-        start_brk, arg_start, arg_end, env_start, env_end;
-    int long           cutime, cstime, priority, nice, num_threads, itrealvalue, rss, cguest_time;
+    unsigned long minflt, cminflt, majflt, cmajflt, vsize, rsslim, startcode, endcode, startstack, kstkesp, kstkeip,
+        signal, blocked, sigignore, sigcatch, wchan, nswap, cnswap, guest_time, start_data, end_data, start_brk,
+        arg_start, arg_end, env_start, env_end;
+    int long           cutime, cstime, priority, nice, itrealvalue, rss, cguest_time;
     unsigned long long starttime, delaycct_blkio_ticks;
     char               state;
     std::string        comm;

lib/src/system/CMakeLists.txt

@@ -1,5 +1,5 @@
 #
-# Copyright 2013-2020 Software Radio Systems Limited
+# Copyright 2013-2021 Software Radio Systems Limited
 #
 # By using this file, you agree to the terms and conditions set
 # forth in the LICENSE file which can be found at the top level of
@@ -7,7 +7,7 @@
 #
 
 set(SOURCES
-    sys_metrics_processor.cpp)
+        sys_metrics_processor.cc)
 
 find_package(Threads REQUIRED)
 

lib/src/system/sys_metrics_processor.cc

@@ -32,6 +32,10 @@ sys_metrics_processor::proc_stats_info::proc_stats_info()
   std::string line;
   {
     std::ifstream file("/proc/self/stat");
+    if (!file) {
+      return;
+    }
+
     std::getline(file, line);
   }