First steps in make signals more abstract from the underlying mechanism; replace epoll with poll.

We now don't assume that a signal equals a single fd (eventfd on Linux).
The next step would be to create a version of signal.c that uses a pipe
internally, so it can be used on other platforms, like *BSD.

This is also the reason epoll was replaced with poll in uplink.c

1 files changed, 20 insertions, 11 deletions

diff --git a/src/shared/signal.h b/src/shared/signal.h
index 6fd2765..3eea6fb 100644
--- a/src/shared/signal.h
+++ b/src/shared/signal.h
@@ -5,23 +5,25 @@
 #define SIGNAL_TIMEOUT (-2)
 #define SIGNAL_ERROR (-1)
 
+typedef struct _dnbd3_signal dnbd3_signal_t;
+
 /**
- * Create a new signal fd (eventfd), nonblocking.
- * @return >= 0 on success, which is the fd; < 0 on error
+ * Create a new signal, nonblocking.
+ * @return NULL on error, pointer to dnbd3_signal_t on success.
  */
-int signal_new();
+dnbd3_signal_t* signal_new();
 
 /**
- * Create a new signal fd (eventfd), blocking.
- * @return >= 0 on success, which is the fd; < 0 on error
+ * Create a new signal, blocking.
+ * @return NULL on error, pointer to dnbd3_signal_t on success.
  */
-int signal_newBlocking();
+dnbd3_signal_t* signal_newBlocking();
 
 /**
  * Trigger the given signal, so a wait or clear call will succeed.
  * @return SIGNAL_OK on success, SIGNAL_ERROR on error
  */
-int signal_call(int signalFd);
+int signal_call(const dnbd3_signal_t* const signal);
 
 /**
  * Wait for given signal, with an optional timeout.
@@ -31,18 +33,25 @@ int signal_call(int signalFd);
  *    SIGNAL_TIMEOUT if the timeout was reached,
  *    SIGNAL_ERROR if some error occured
  */
-int signal_wait(int signalFd, int timeoutMs);
+int signal_wait(const dnbd3_signal_t* const signal, int timeoutMs);
 
 /**
- * Clears any pending signals on this signal fd.
+ * Clears any pending signals on this signal.
  * @return number of signals that were pending,
  *    SIGNAL_ERROR if some error occured
  */
-int signal_clear(int signalFd);
+int signal_clear(const dnbd3_signal_t* const signal);
 
 /**
  * Close the given signal.
  */
-void signal_close(int signalFd);
+void signal_close(const dnbd3_signal_t* const signal);
+
+/**
+ * Get a file descriptor for the given signal that can be
+ * waited on using poll or similar.
+ * @return -1 if the signal is invalid
+ */
+int signal_getWaitFd(const dnbd3_signal_t* const signal);
 
 #endif