io: allow overriding poll function.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/ccan/io/backend.h b/ccan/io/backend.h
index 3e158a3669174b60ad766b060fd85eb15294b4ab..c8ceb4e864397c5e54c54fe20c3ceddaae2c9e20 100644 (file)
--- a/ccan/io/backend.h
+++ b/ccan/io/backend.h
@@ -2,7 +2,6 @@
 #ifndef CCAN_IO_BACKEND_H
 #define CCAN_IO_BACKEND_H
 #include <stdbool.h>
-#include <poll.h>
 #include "io_plan.h"
 #include <ccan/list/list.h>
 

diff --git a/ccan/io/io.h b/ccan/io/io.h
index fe42b53736005c4459c3b56afbbaa87ffe46f04a..11eeade63f820c2be20a296c6c7583f771b002a3 100644 (file)
--- a/ccan/io/io.h
+++ b/ccan/io/io.h
@@ -4,6 +4,7 @@
 #include <ccan/tal/tal.h>
 #include <ccan/typesafe_cb/typesafe_cb.h>
 #include <stdbool.h>
+#include <poll.h>
 #include <unistd.h>
 
 struct timers;
@@ -701,4 +702,14 @@ bool io_flush_sync(struct io_conn *conn);
  */
 struct timemono (*io_time_override(struct timemono (*now)(void)))(void);
 
+/**
+ * io_poll_override - override the normal call for poll.
+ * @pollfn: the function to call.
+ *
+ * io usually uses poll() internally, but this forces it to use your
+ * function (eg. for debugging, suppressing fds, or polling on others unknown
+ * to ccan/io).  Returns the old one.
+ */
+int (*io_poll_override(int (*poll)(struct pollfd *fds, nfds_t nfds, int timeout)))(struct pollfd *, nfds_t, int);
+
 #endif /* CCAN_IO_H */

diff --git a/ccan/io/poll.c b/ccan/io/poll.c
index 043feff74046226e61c367ad68644f3aba3fb54e..a4e83ed761e77251767b01b3e3f5c5dd3492bfcd 100644 (file)
--- a/ccan/io/poll.c
+++ b/ccan/io/poll.c
@@ -17,6 +17,7 @@ static struct fd **fds = NULL;
 static LIST_HEAD(closing);
 static LIST_HEAD(always);
 static struct timemono (*nowfn)(void) = time_mono;
+static int (*pollfn)(struct pollfd *fds, nfds_t nfds, int timeout) = poll;
 
 struct timemono (*io_time_override(struct timemono (*now)(void)))(void)
 {
@@ -25,6 +26,13 @@ struct timemono (*io_time_override(struct timemono (*now)(void)))(void)
        return old;
 }
 
+int (*io_poll_override(int (*poll)(struct pollfd *fds, nfds_t nfds, int timeout)))(struct pollfd *, nfds_t, int)
+{
+       int (*old)(struct pollfd *fds, nfds_t nfds, int timeout) = pollfn;
+       pollfn = poll;
+       return old;
+}
+
 static bool add_fd(struct fd *fd, short events)
 {
        if (!max_fds) {
@@ -269,7 +277,7 @@ void *io_loop(struct timers *timers, struct timer **expired)
                        }
                }
 
-               r = poll(pollfds, num_fds, ms_timeout);
+               r = pollfn(pollfds, num_fds, ms_timeout);
                if (r < 0)
                        break;
 

diff --git a/ccan/io/test/run-41-io_poll_override.c b/ccan/io/test/run-41-io_poll_override.c
new file mode 100644 (file)
index 0000000..0a62e2d
--- /dev/null
+++ b/ccan/io/test/run-41-io_poll_override.c
@@ -0,0 +1,57 @@
+#include <ccan/io/io.h>
+/* Include the C files directly. */
+#include <ccan/io/poll.c>
+#include <ccan/io/io.c>
+#include <ccan/tap/tap.h>
+#include <sys/wait.h>
+#include <stdio.h>
+
+#define PORT "65020"
+
+/* Should be looking to read from one fd. */
+static int mypoll(struct pollfd *fds, nfds_t nfds, int timeout)
+{
+       ok1(nfds == 1);
+       ok1(fds[0].fd >= 0);
+       ok1(fds[0].events & POLLIN);
+       ok1(!(fds[0].events & POLLOUT));
+
+       /* Pretend it's readable. */
+       fds[0].revents = POLLIN;
+       return 1;
+}
+
+static int check_cant_read(int fd, struct io_plan_arg *arg)
+{
+       char c;
+       ssize_t ret = read(fd, &c, 1);
+
+       ok1(errno == EAGAIN || errno == EWOULDBLOCK);
+       ok1(ret == -1);
+
+       return 1;
+}
+
+static struct io_plan *setup_conn(struct io_conn *conn, void *unused)
+{
+       /* Need to get this to mark it IO_POLLING */
+       io_plan_arg(conn, IO_IN);
+       return io_set_plan(conn, IO_IN, check_cant_read, io_close_cb, NULL);
+}
+
+int main(void)
+{
+       int fds[2];
+
+       plan_tests(8);
+
+       pipe(fds);
+       ok1(io_poll_override(mypoll) == poll);
+
+       io_new_conn(NULL, fds[0], setup_conn, NULL);
+       ok1(io_loop(NULL, NULL) == NULL);
+       close(fds[1]);
+
+       /* This exits depending on whether all tests passed */
+       return exit_status();
+}