prevent a crash when sysfs and proc are not readableHEADmaster

The program used to return an empty list of devices.
Nevertheless, the method printTraffic of TrafficWindow does not handle
empty lists.

Fixed by throwing an exception whenever proc and sysfs are both
unaccessible.

Signed-off-by: Olivier Gayot <duskcoder@gmail.com>

2 files changed, 16 insertions, 3 deletions

diff --git a/src/devreader-linux.cpp b/src/devreader-linux.cpp
index 5b6e9eb..85824cd 100644
--- a/src/devreader-linux.cpp
+++ b/src/devreader-linux.cpp
@@ -14,6 +14,8 @@
 #include <string>
 #include <list>
 
+#include <stdexcept>
+
 using namespace std;
 
 bool DevReaderLinux::isAvailable()
@@ -28,6 +30,6 @@ list<string> DevReaderLinux::findAllDevices()
     else if(DevReaderLinuxProc::isAvailable())
         return DevReaderLinuxProc::findAllDevices();
     else
-        return list<string>();
+        throw std::runtime_error("neither sysfs nor proc is available");
 }
 
diff --git a/src/main.cpp b/src/main.cpp
index c53e142..5b32183 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -48,6 +48,8 @@
 #include <string>
 #include <vector>
 
+#include <stdexcept>
+
 #include <ctype.h>
 #include <time.h>
 #include <curses.h>
@@ -352,8 +354,17 @@ int main(int argc, char *argv[])
         }
     }
 
-    // auto-detect network devices
-    DevReaderFactory::findAllDevices();
+    try
+    {
+        // auto-detect network devices
+        DevReaderFactory::findAllDevices();
+    }
+    catch (std::runtime_error e)
+    {
+        cerr << "Cannot find any device: " << e.what() << endl;
+        return -1;
+    };
+
     const map<string, DevReader*>& deviceReaders = DevReaderFactory::getAllDevReaders();
 
     // create one instance of the Device class per device