[3669] Added some more commentary in various places.

src/lib/dhcpsrv/memfile_lease_mgr.cc

@@ -809,9 +809,9 @@ void Memfile_LeaseMgr::lfcExecute(boost::shared_ptr<LeaseFileType>& lease_file)
     // This string will hold a reason for the failure to rote the lease files.
     std::string error_string = "(no details)";
     // Check if the copy of the lease file exists already. If it does, it
-    // is an indication that another LFC instance may be in progress, in
-    // which case we don't want to rotate the current lease file to avoid
-    // overriding the contents of the existing file.
+    // is an indication that another LFC instance may be in progress or
+    // may be stalled. In that case we don't want to rotate the current
+    // lease file to avoid overriding the contents of the existing file.
     CSVFile lease_file_copy(appendSuffix(lease_file->getFilename(), FILE_INPUT));
     if (!lease_file_copy.exists()) {
         // Close the current file so as we can move it to the copy file.
@@ -849,8 +849,8 @@ void Memfile_LeaseMgr::lfcExecute(boost::shared_ptr<LeaseFileType>& lease_file)
             error_string = ex.what();
         }
     }
-    // Once we have rotated files as needed, start the new kea-lfc process
-    // to perform a cleanup.
+    // Once the files have been rotated, or untouched if another LFC had
+    // not finished, a new process is started.
     if (do_lfc) {
         lfc_setup_->execute();
 

src/lib/dhcpsrv/memfile_lease_mgr.h

@@ -339,12 +339,12 @@ public:
     /// This enumeration is used by a method which appends the appropriate
     /// suffix to the lease file name.
     enum LFCFileType {
-        FILE_CURRENT,
-        FILE_INPUT,
-        FILE_PREVIOUS,
-        FILE_OUTPUT,
-        FILE_FINISH,
-        FILE_PID
+        FILE_CURRENT,  ///< %Lease File
+        FILE_INPUT,    ///< %Lease File Copy
+        FILE_PREVIOUS, ///< Previous %Lease File
+        FILE_OUTPUT,   ///< LFC Output File
+        FILE_FINISH,   ///< LFC Finish File
+        FILE_PID       ///< PID File
     };
 
     /// @brief Appends appropriate suffix to the file name.

src/lib/dhcpsrv/tests/lease_file_io.h

@@ -1,4 +1,4 @@
-// Copyright (C) 2014 Internet Systems Consortium, Inc. ("ISC")
+// Copyright (C) 2014-2015 Internet Systems Consortium, Inc. ("ISC")
 //
 // Permission to use, copy, modify, and/or distribute this software for any
 // purpose with or without fee is hereby granted, provided that the above

src/lib/util/process_spawn.cc

@@ -48,11 +48,11 @@ public:
 
     /// @brief Spawn the new process.
     ///
-    /// This method forks the current process and execues the specified
+    /// This method forks the current process and executes the specified
     /// binary with arguments within the child process.
     ///
     /// The child process will return EXIT_FAILURE if the method was unable
-    /// to start the exuctable, e.g. as a result of insufficient permissions
+    /// to start the executable, e.g. as a result of insufficient permissions
     /// or when the executable does not exist. If the process ends successfully
     /// the EXIT_SUCCESS is returned.
     ///
@@ -131,7 +131,7 @@ ProcessSpawnImpl::ProcessSpawnImpl(const std::string& executable,
                                    const ProcessArgs& args)
     : signals_(new SignalSet(SIGCHLD)), process_status_(),
       executable_(executable), args_(new char*[args.size() + 2]) {
-    // Set the handler which is invoked immediatelly when the signal
+    // Set the handler which is invoked immediately when the signal
     // is received.
     signals_->setOnReceiptHandler(boost::bind(&ProcessSpawnImpl::waitForProcess,
                                               this, _1));
@@ -199,7 +199,7 @@ bool
 ProcessSpawnImpl::isRunning(const pid_t pid) const {
     if (process_status_.find(pid) == process_status_.end()) {
         isc_throw(BadValue, "the process with the pid '" << pid
-                  << "' hasn't been spawned and it status cannnot be"
+                  << "' hasn't been spawned and it status cannot be"
                   " returned");
     }
     return ((pid != 0) && (kill(pid, 0) == 0));

src/lib/util/tests/process_spawn_app.sh

@@ -14,6 +14,24 @@
 # OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 # PERFORMANCE OF THIS SOFTWARE.
 
+
+# This script is used for testing the ProcessSpawn utility class. This
+# class is used to fork and execute a new process. It also allows for
+# checking the exit code returned when the process terminates.
+# The unit tests execute this script via ProcessSpawn class with
+# different command line parameters to test the class functionality.
+#
+# In particular, they check if the class correctly records the exit code
+# returned. The exit code returned is controlled by the caller. It is
+# possible to explictily specify the exit code to be returned using
+# the command line options. It is also possible to specify that the
+# exit code is "unique" for the process, so as the test can check
+# that two distinct processes spawned by the same ProcessSpawn
+# object may return different status code. The command line of this
+# script also allows for forcing the process to sleep so as the
+# test has much enough time to verify that the convenience methods
+# checking the state of the process, i.e. process running or not.
+
 exit_code=
 
 while [ ! -z "${1}" ]
@@ -29,6 +47,10 @@ do
             shift
             exit_code=${1}
             ;;
+        -s)
+            shift
+            sleep ${1}
+            ;;
         *)
             exit 123
             ;;
@@ -36,6 +58,8 @@ do
     shift
 done
 
+# The exit code of 32 is returned when no args specified or
+# when only the -s arg has been specified.
 if [ -z "${exit_code}" ]; then
     exit 32;
 fi

src/lib/util/tests/process_spawn_unittest.cc

@@ -150,4 +150,23 @@ TEST(ProcessSpawn, getCommandLine) {
     }
 }
 
+// This test verifies that it is possible to check if the process is
+// running.
+TEST(ProcessSpawn, isRunning) {
+    // Run the process which sleeps for 10 seconds, so as we have
+    // enough time to check if it is running.
+    std::vector<std::string> args;
+    args.push_back("-s");
+    args.push_back("10");
+    ProcessSpawn process(getApp(), args);
+    pid_t pid = 0;
+    ASSERT_NO_THROW(pid = process.spawn());
+    EXPECT_TRUE(process.isRunning(pid));
+
+    // Kill the process.
+    ASSERT_EQ(0, kill(pid, SIGKILL));
+    // And make sure if died.
+    ASSERT_TRUE(waitForProcess(process, pid, 2));
+}
+
 } // end of anonymous namespace