/**
* @file include/gnunet_helper_lib.h
- * @brief API for dealing with (SUID) helper processes that communicate via GNUNET_MessageHeaders on stdin/stdout
+ * @brief API for dealing with (SUID) helper processes that communicate via
+ * GNUNET_MessageHeaders on stdin/stdout
* @author Philipp Toelke
* @author Christian Grothoff
*/
+
#ifndef GNUNET_HELPER_LIB_H
#define GNUNET_HELPER_LIB_H
/**
- * @brief Starts a helper and begins reading from it
+ * Callback that will be called when the helper process dies. This is not called
+ * when the helper process is stoped using GNUNET_HELPER_stop()
+ *
+ * @param cls the closure from GNUNET_HELPER_start()
+ */
+typedef void (*GNUNET_HELPER_ExceptionCallback) (void *cls);
+
+
+/**
+ * Starts a helper and begins reading from it. The helper process is
+ * restarted when it dies except when it is stopped using GNUNET_HELPER_stop()
+ * or when the exp_cb callback is not NULL.
*
+ * @param with_control_pipe does the helper support the use of a control pipe for signalling?
* @param binary_name name of the binary to run
* @param binary_argv NULL-terminated list of arguments to give when starting the binary (this
* argument must not be modified by the client for
* the lifetime of the helper handle)
* @param cb function to call if we get messages from the helper
- * @param cb_cls Closure for the callback
+ * @param exp_cb the exception callback to call. Set this to NULL if the helper
+ * process has to be restarted automatically when it dies/crashes
+ * @param cb_cls closure for the above callbacks
* @return the new Handle, NULL on error
*/
struct GNUNET_HELPER_Handle *
-GNUNET_HELPER_start (const char *binary_name,
+GNUNET_HELPER_start (int with_control_pipe,
+ const char *binary_name,
char *const binary_argv[],
- GNUNET_SERVER_MessageTokenizerCallback cb, void *cb_cls);
+ GNUNET_SERVER_MessageTokenizerCallback cb,
+ GNUNET_HELPER_ExceptionCallback exp_cb,
+ void *cb_cls);
/**
- * @brief Kills the helper, closes the pipe and frees the handle
+ * Sends termination signal to the helper process. The helper process is not
+ * reaped; call GNUNET_HELPER_wait() for reaping the dead helper process.
+ *
+ * @param h the helper handle
+ * @param soft_kill if #GNUNET_YES, signals termination by closing the helper's
+ * stdin; #GNUNET_NO to signal termination by sending SIGTERM to helper
+ * @return #GNUNET_OK on success; #GNUNET_SYSERR on error
+ */
+int
+GNUNET_HELPER_kill (struct GNUNET_HELPER_Handle *h, int soft_kill);
+
+
+/**
+ * Reap the helper process. This call is blocking (!). The helper process
+ * should either be sent a termination signal before or should be dead before
+ * calling this function
+ *
+ * @param h the helper handle
+ * @return #GNUNET_OK on success; #GNUNET_SYSERR on error
+ */
+int
+GNUNET_HELPER_wait (struct GNUNET_HELPER_Handle *h);
+
+
+/**
+ * Free's the resources occupied by the helper handle
+ *
+ * @param h the helper handle to free
+ */
+void
+GNUNET_HELPER_destroy (struct GNUNET_HELPER_Handle *h);
+
+
+/**
+ * Kills the helper, closes the pipe, frees the handle and calls wait() on the
+ * helper process
*
* @param h handle to helper to stop
+ * @param soft_kill if #GNUNET_YES, signals termination by closing the helper's
+ * stdin; #GNUNET_NO to signal termination by sending SIGTERM to helper
*/
void
-GNUNET_HELPER_stop (struct GNUNET_HELPER_Handle *h);
+GNUNET_HELPER_stop (struct GNUNET_HELPER_Handle *h, int soft_kill);
/**
* Continuation function.
- *
+ *
* @param cls closure
- * @param result GNUNET_OK on success,
- * GNUNET_NO if helper process died
- * GNUNET_SYSERR during GNUNET_HELPER_stop
+ * @param result #GNUNET_OK on success,
+ * #GNUNET_NO if helper process died
+ * #GNUNET_SYSERR during GNUNET_HELPER_destroy
*/
typedef void (*GNUNET_HELPER_Continuation)(void *cls,
int result);
* @param h helper to send message to
* @param msg message to send
* @param can_drop can the message be dropped if there is already one in the queue?
- * @param cont continuation to run once the message is out
- * @param cont_cls closure for 'cont'
- * @return NULL if the message was dropped,
- * otherwise handle to cancel *cont* (actual transmission may
+ * @param cont continuation to run once the message is out (#GNUNET_OK on succees, #GNUNET_NO
+ * if the helper process died, #GNUNET_SYSERR during #GNUNET_HELPER_destroy).
+ * @param cont_cls closure for @a cont
+ * @return NULL if the message was dropped,
+ * otherwise handle to cancel @a cont (actual transmission may
* not be abortable)
*/
struct GNUNET_HELPER_SendHandle *
-GNUNET_HELPER_send (struct GNUNET_HELPER_Handle *h,
+GNUNET_HELPER_send (struct GNUNET_HELPER_Handle *h,
const struct GNUNET_MessageHeader *msg,
int can_drop,
GNUNET_HELPER_Continuation cont,
/**
- * Cancel a 'send' operation. If possible, transmitting the
- * message is also aborted, but at least 'cont' won't be
- * called.
+ * Cancel a #GNUNET_HELPER_send operation. If possible, transmitting
+ * the message is also aborted, but at least 'cont' won't be called.
*
* @param sh operation to cancel
*/
void
GNUNET_HELPER_send_cancel (struct GNUNET_HELPER_SendHandle *sh);
-#endif /* end of include guard: GNUNET_HELPER_LIB_H */
+#endif
+/* end of include guard: GNUNET_HELPER_LIB_H */
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