io/fdpass: new module for async fd passing.

[ccan] / ccan / io / fdpass / _info

diff --git a/ccan/io/fdpass/_info b/ccan/io/fdpass/_info
new file mode 100644 (file)
index 0000000..406b2f5
--- /dev/null
+++ b/ccan/io/fdpass/_info
@@ -0,0 +1,95 @@
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+
+/**
+ * io/fdpass - IO helper for passing file descriptors across local sockets
+ *
+ * This code adds the ability to pass file descriptors to ccan/io.
+ *
+ * License: LGPL (v2.1 or any later version)
+ * Author: Rusty Russell <rusty@rustcorp.com.au>
+ *
+ * Example:
+ *     // Given "hello" outputs hello
+ *     #include <ccan/io/fdpass/fdpass.h>
+ *     #include <sys/types.h>
+ *     #include <sys/socket.h>
+ *     #include <sys/un.h>
+ *     #include <stdio.h>
+ *     #include <stdlib.h>
+ *     #include <unistd.h>
+ *
+ *     // Child reads stdin into the buffer, prints it out.
+ *     struct buf {
+ *             size_t used;
+ *             char c[100];
+ *     };
+ *     static struct io_plan *read_more(struct io_conn *conn, struct buf *buf)
+ *     {
+ *             printf("%.*s", (int)buf->used, buf->c);
+ *             return io_read_partial(conn, buf->c, sizeof(buf->c), &buf->used,
+ *                                     read_more, buf);
+ *     }
+ *
+ *     // Child has received fd, start reading loop.
+ *     static struct io_plan *got_infd(struct io_conn *conn, int *infd)
+ *     {
+ *             struct buf *buf = calloc(1, sizeof(*buf));
+ *
+ *             io_new_conn(NULL, *infd, read_more, buf);
+ *             return io_close(conn);
+ *     }
+ *     // Child is receiving the fd to read into. 
+ *     static struct io_plan *recv_infd(struct io_conn *conn, int *infd)
+ *     {
+ *             return io_recv_fd(conn, infd, got_infd, infd);
+ *     }
+ *
+ *     // Gets passed fd (stdin), which it reads from.
+ *     static void child(int sockfd)
+ *     {
+ *             int infd;
+ *
+ *             io_new_conn(NULL, sockfd, recv_infd, &infd);
+ *             io_loop(NULL, NULL);
+ *             exit(0);
+ *     }
+ *
+ *     static struct io_plan *send_stdin(struct io_conn *conn, void *unused)
+ *     {
+ *             return io_send_fd(conn, STDIN_FILENO, io_close_cb, NULL);
+ *     }
+ *
+ *     static void parent(int sockfd)
+ *     {
+ *             io_new_conn(NULL, sockfd, send_stdin, NULL);
+ *             io_loop(NULL, NULL);
+ *             exit(0);
+ *     }
+ *     
+ *     int main(void)
+ *     {
+ *             int sv[2];
+ *     
+ *             socketpair(AF_UNIX, SOCK_STREAM, 0, sv);
+ *             if (fork() == 0)
+ *                     child(sv[0]);
+ *             else
+ *                     parent(sv[1]);
+ *     }
+ */
+int main(int argc, char *argv[])
+{
+       /* Expect exactly one argument */
+       if (argc != 2)
+               return 1;
+
+       if (strcmp(argv[1], "depends") == 0) {
+               printf("ccan/fdpass\n");
+               printf("ccan/io\n");
+               return 0;
+       }
+
+       return 1;
+}