posix: add signalfd wrappers

core/posix.hh

@@ -13,6 +13,8 @@
 #include <sys/ioctl.h>
 #include <sys/eventfd.h>
 #include <sys/timerfd.h>
+#include <sys/signalfd.h>
+#include <signal.h>
 #include <boost/optional.hpp>
 
 inline void throw_system_error_on(bool condition);
@@ -70,6 +72,11 @@ public:
         throw_system_error_on(fd == -1);
         return file_desc(fd);
     }
+    static file_desc signalfd(const sigset_t& mask, int flags) {
+        int fd = ::signalfd(-1, &mask, flags);
+        throw_system_error_on(fd == -1);
+        return file_desc(fd);
+    }
     file_desc accept(sockaddr& sa, socklen_t& sl, int flags = 0) {
         auto ret = ::accept4(_fd, &sa, &sl, flags);
         throw_system_error_on(ret == -1);
@@ -178,4 +185,12 @@ void throw_kernel_error(T r) {
     }
 }
 
+inline
+sigset_t make_sigset_mask(int signo) {
+    sigset_t set;
+    sigemptyset(&set);
+    sigaddset(&set, signo);
+    return set;
+}
+
 #endif /* FILE_DESC_HH_ */