ccan/io: check for all idle.

It's probably a bug if we're waiting for nothing.

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

diff --git a/ccan/io/poll.c b/ccan/io/poll.c
index fdff271c64f26e09f060b9e52e468dcf80d97696..7ceb8a7eec8bc6fd3f3de65c0c22e27a2e20e43e 100644 (file)
--- a/ccan/io/poll.c
+++ b/ccan/io/poll.c
@@ -7,7 +7,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 
-static size_t num_fds = 0, max_fds = 0, num_next = 0, num_finished = 0;
+static size_t num_fds = 0, max_fds = 0, num_next = 0, num_finished = 0, num_waiting = 0;
 static struct pollfd *pollfds = NULL;
 static struct fd **fds = NULL;
 
@@ -65,7 +65,10 @@ static void del_fd(struct fd *fd)
 
 bool add_listener(struct io_listener *l)
 {
-       return add_fd(&l->fd, POLLIN);
+       if (!add_fd(&l->fd, POLLIN))
+               return false;
+       num_waiting++;
+       return true;
 }
 
 bool add_conn(struct io_conn *c)
@@ -123,6 +126,9 @@ void backend_set_state(struct io_conn *conn, struct io_op *op)
        enum io_state state = from_ioop(op);
        struct pollfd *pfd = &pollfds[conn->fd.backend_info];
 
+       if (pfd->events)
+               num_waiting--;
+
        pfd->events = pollmask(state);
        if (conn->duplex) {
                int mask = pollmask(conn->duplex->state);
@@ -130,6 +136,8 @@ void backend_set_state(struct io_conn *conn, struct io_op *op)
                assert(!mask || pfd->events != mask);
                pfd->events |= mask;
        }
+       if (pfd->events)
+               num_waiting++;
 
        if (state == NEXT)
                num_next++;
@@ -206,6 +214,9 @@ void *io_loop(void)
                if (num_fds == 0)
                        break;
 
+               /* You can't tell them all to go to sleep! */
+               assert(num_waiting);
+
                r = poll(pollfds, num_fds, -1);
                if (r < 0)
                        break;

diff --git a/ccan/io/test/run-13-all-idle.c b/ccan/io/test/run-13-all-idle.c
new file mode 100644 (file)
index 0000000..b6a52a5
--- /dev/null
+++ b/ccan/io/test/run-13-all-idle.c
@@ -0,0 +1,36 @@
+#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>
+#include <signal.h>
+
+static struct io_op *start(struct io_conn *conn, void *unused)
+{
+       return io_idle(conn);
+}
+
+int main(void)
+{
+       int status;
+
+       plan_tests(3);
+
+       if (fork() == 0) {
+               int fds[2];
+
+               ok1(pipe(fds) == 0);
+               io_new_conn(fds[0], start, NULL, NULL);
+               io_loop();
+               exit(1);
+       }
+
+       ok1(wait(&status) != -1);
+       ok1(WIFSIGNALED(status));
+       ok1(WTERMSIG(status) == SIGABRT);
+
+       /* This exits depending on whether all tests passed */
+       return exit_status();
+}