From 959343899a38dd5bf2b2efb8de41eba15e078e22 Mon Sep 17 00:00:00 2001
From: Sapan Bhatia <sapanb@cs.princeton.edu>
Date: Fri, 3 Apr 2009 02:27:06 +0000
Subject: [PATCH] Looking like I forgot to add this.
---
lib/fdpass.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++
lib/fdpass.h | 5 +++
2 files changed, 98 insertions(+)
create mode 100644 lib/fdpass.c
create mode 100644 lib/fdpass.h
diff --git a/lib/fdpass.c b/lib/fdpass.c
new file mode 100644
index 0000000..5548064
--- /dev/null
+++ b/lib/fdpass.c
@@ -0,0 +1,93 @@
+// Modified version of library functions in FUSE
+//
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mount.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+int send_fd(int sock_fd, int fd)
+{
+ int retval;
+ struct msghdr msg;
+ struct cmsghdr *p_cmsg;
+ struct iovec vec;
+ size_t cmsgbuf[CMSG_SPACE(sizeof(fd)) / sizeof(size_t)];
+ int *p_fds;
+ char sendchar = 0;
+
+ msg.msg_control = cmsgbuf;
+ msg.msg_controllen = sizeof(cmsgbuf);
+ p_cmsg = CMSG_FIRSTHDR(&msg);
+ p_cmsg->cmsg_level = SOL_SOCKET;
+ p_cmsg->cmsg_type = SCM_RIGHTS;
+ p_cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
+ p_fds = (int *) CMSG_DATA(p_cmsg);
+ *p_fds = fd;
+ msg.msg_controllen = p_cmsg->cmsg_len;
+ msg.msg_name = NULL;
+ msg.msg_namelen = 0;
+ msg.msg_iov = &vec;
+ msg.msg_iovlen = 1;
+ msg.msg_flags = 0;
+ /* "To pass file descriptors or credentials you need to send/read at
+ * least one byte" (man 7 unix) */
+ vec.iov_base = &sendchar;
+ vec.iov_len = sizeof(sendchar);
+ while ((retval = sendmsg(sock_fd, &msg, 0)) == -1 && errno == EINTR);
+ if (retval != 1) {
+ perror("sending file descriptor");
+ return -1;
+ }
+ return 0;
+}
+
+
+/* return value:
+ * >= 0 => fd
+ * -1 => error
+ */
+int receive_fd(int fd)
+{
+ struct msghdr msg;
+ struct iovec iov;
+ char buf[1];
+ int rv;
+ size_t ccmsg[CMSG_SPACE(sizeof(int)) / sizeof(size_t)];
+ struct cmsghdr *cmsg;
+
+ iov.iov_base = buf;
+ iov.iov_len = 1;
+
+ msg.msg_name = 0;
+ msg.msg_namelen = 0;
+ msg.msg_iov = &iov;
+ msg.msg_iovlen = 1;
+ /* old BSD implementations should use msg_accrights instead of
+ * msg_control; the interface is different. */
+ msg.msg_control = ccmsg;
+ msg.msg_controllen = sizeof(ccmsg);
+
+ while(((rv = recvmsg(fd, &msg, 0)) == -1) && errno == EINTR);
+ if (rv == -1) {
+ perror("recvmsg");
+ return -1;
+ }
+ if(!rv) {
+ /* EOF */
+ return -1;
+ }
+
+ cmsg = CMSG_FIRSTHDR(&msg);
+ if (!cmsg->cmsg_type == SCM_RIGHTS) {
+ fprintf(stderr, "got control message of unknown type %d\n",
+ cmsg->cmsg_type);
+ return -1;
+ }
+ return *(int*)CMSG_DATA(cmsg);
+}
+
diff --git a/lib/fdpass.h b/lib/fdpass.h
new file mode 100644
index 0000000..f00a6fb
--- /dev/null
+++ b/lib/fdpass.h
@@ -0,0 +1,5 @@
+// Modified version of library functions in FUSE
+//
+int send_fd(int sock_fd, int fd);
+int receive_fd(int fd);
+
--
2.47.0