ProcStats: Attempt to reconnection to process proc stat when information appeats corrupted

GaudiAud/src/ProcStats.cpp

@@ -30,10 +30,6 @@
 #  endif // __linux__
 #  include <cstdio>
 
-using std::cerr;
-using std::cout;
-using std::endl;
-
 /* Format of the Linux proc/stat (man 5 proc, kernel 2.6.35):
  pid %d      The process ID.
 
@@ -245,17 +241,19 @@ ProcStats* ProcStats::instance() {
   return &inst;
 }
 
-ProcStats::ProcStats() {
+void ProcStats::open_ufd() {
+  m_valid = false;
 #if defined( __linux__ ) or defined( __APPLE__ )
+  m_ufd.close();
   m_pg_size        = sysconf( _SC_PAGESIZE ); // getpagesize();
   const auto fname = "/proc/" + std::to_string( getpid() ) + "/stat";
   m_ufd.open( fname.c_str(), O_RDONLY );
   if ( !m_ufd ) {
-    cerr << "Failed to open " << fname << endl;
-    return;
+    std::cerr << "ProcStats : Failed to open " << fname << std::endl;
+  } else {
+    m_valid = true;
   }
 #endif // __linux__ or __APPLE__
-  m_valid = true;
 }
 
 bool ProcStats::fetch( procInfo& f ) {
@@ -273,7 +271,7 @@ bool ProcStats::fetch( procInfo& f ) {
   m_ufd.lseek( 0, SEEK_SET );
 
   if ( ( cnt = m_ufd.read( buf, sizeof( buf ) ) ) < 0 ) {
-    cout << "LINUX Read of Proc file failed:" << endl;
+    std::cerr << "ProcStats : LINUX Read of Proc file failed:" << std::endl;
     return false;
   }
 
@@ -298,6 +296,11 @@ bool ProcStats::fetch( procInfo& f ) {
 
     f.vsize = pr_size / ( 1024 * 1024 );
     f.rss   = pr_rssize * m_pg_size / ( 1024 * 1024 );
+
+    if ( 0 == pinfo.vsize ) {
+      std::cerr << "ProcStats : 0==vsize -> Will try reopening process proc stats" << std::endl;
+      open_ufd();
+    }
   }
 
 #else

GaudiAud/src/ProcStats.h

@@ -51,41 +51,49 @@ struct procInfo {
 };
 
 class ProcStats {
+
 public:
-  static ProcStats* instance();
+  ProcStats() { open_ufd(); }
+
+private:
+  void open_ufd();
 
-  bool fetch( procInfo& fill_me );
-  auto pageSize() const noexcept { return m_pg_size; }
-  ProcStats();
+public:
+  static ProcStats* instance();
+  bool              fetch( procInfo& fill_me );
+  auto              pageSize() const noexcept { return m_pg_size; }
 
 private:
   class unique_fd {
 
   private:
     int m_fd{ -1 };
+
+  private:
     unique_fd( const unique_fd& ) = delete;
     unique_fd& operator=( const unique_fd& ) = delete;
 
   public:
-    unique_fd( int fd = -1 ) : m_fd( fd ) {}
+    unique_fd( const int fd = -1 ) : m_fd( fd ) {}
     unique_fd( unique_fd&& other ) {
       m_fd       = other.m_fd;
       other.m_fd = -1;
     }
-    ~unique_fd() {
-      if ( m_fd != -1 ) { ::close( m_fd ); }
-    }
+    ~unique_fd() { close(); }
 
+  public:
     explicit operator bool() const { return m_fd != -1; }
     template <typename... Args>
     unique_fd& open( Args&&... args ) {
       m_fd = ::open( std::forward<Args>( args )... );
       return *this;
     }
-
     int close() {
-      auto r = ::close( m_fd );
-      m_fd   = -1;
+      int r = 0;
+      if ( m_fd != -1 ) {
+        r    = ::close( m_fd );
+        m_fd = -1;
+      }
       return r;
     }