Add a wrapper for signalfd
The wrapper blocks (and unblock) signals for the thread as well.
This will get tested by the wakeup for the IPC.
Change-Id: Ica701034e8890fc0689b8528b4d7448fd630ed64
diff --git a/aos/ipc_lib/signalfd.cc b/aos/ipc_lib/signalfd.cc
new file mode 100644
index 0000000..1679b46
--- /dev/null
+++ b/aos/ipc_lib/signalfd.cc
@@ -0,0 +1,47 @@
+#include "aos/ipc_lib/signalfd.h"
+
+#include <signal.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <initializer_list>
+
+#include "aos/logging/logging.h"
+
+namespace aos {
+namespace ipc_lib {
+
+SignalFd::SignalFd(::std::initializer_list<int> signals) {
+ // Build up the mask with the provided signals.
+ sigemptyset(&mask_);
+ for (int signal : signals) {
+ sigaddset(&mask_, signal);
+ }
+ // Then build a signalfd. Make it nonblocking so it works well with an epoll
+ // loop, and have it close on exec.
+ PCHECK(fd_ = signalfd(-1, &mask_, SFD_NONBLOCK | SFD_CLOEXEC));
+ // Now that we have a consumer of the signal, block the signals so the
+ // signalfd gets them.
+ pthread_sigmask(SIG_BLOCK, &mask_, nullptr);
+}
+
+SignalFd::~SignalFd() {
+ // Unwind the constructor. Unblock the signals and close the fd.
+ pthread_sigmask(SIG_UNBLOCK, &mask_, nullptr);
+ PCHECK(close(fd_));
+}
+
+signalfd_siginfo SignalFd::Read() {
+ signalfd_siginfo result;
+
+ const int ret =
+ read(fd_, static_cast<void *>(&result), sizeof(signalfd_siginfo));
+ // If we didn't get the right amount of data, signal that there was a problem
+ // by setting the signal number to 0.
+ if (ret != static_cast<int>(sizeof(signalfd_siginfo))) {
+ result.ssi_signo = 0;
+ }
+ return result;
+}
+
+} // namespace ipc_lib
+} // namespace aos