vhost: add number of fds to vhost-user messages

As soon as some ancillary data (fds) are received, it is copied
without checking its length.

This patch adds the number of fds received to the message,
which is set in read_vhost_message().

This is preliminary work to support sending fds to Qemu.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
index d630317478dd855600dc9faa3b28c4b20722cde6..c278e9b5beb1af93d8c70400cbb0fd716b12fb81 100644 (file)
--- a/lib/librte_vhost/socket.c
+++ b/lib/librte_vhost/socket.c
@@ -94,18 +94,23 @@ static struct vhost_user vhost_user = {
        .mutex = PTHREAD_MUTEX_INITIALIZER,
 };
 
-/* return bytes# of read on success or negative val on failure. */
+/*
+ * return bytes# of read on success or negative val on failure. Update fdnum
+ * with number of fds read.
+ */
 int
-read_fd_message(int sockfd, char *buf, int buflen, int *fds, int fd_num)
+read_fd_message(int sockfd, char *buf, int buflen, int *fds, int max_fds,
+               int *fd_num)
 {
        struct iovec iov;
        struct msghdr msgh;
-       size_t fdsize = fd_num * sizeof(int);
-       char control[CMSG_SPACE(fdsize)];
+       char control[CMSG_SPACE(max_fds * sizeof(int))];
        struct cmsghdr *cmsg;
        int got_fds = 0;
        int ret;
 
+       *fd_num = 0;
+
        memset(&msgh, 0, sizeof(msgh));
        iov.iov_base = buf;
        iov.iov_len  = buflen;
@@ -131,13 +136,14 @@ read_fd_message(int sockfd, char *buf, int buflen, int *fds, int fd_num)
                if ((cmsg->cmsg_level == SOL_SOCKET) &&
                        (cmsg->cmsg_type == SCM_RIGHTS)) {
                        got_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+                       *fd_num = got_fds;
                        memcpy(fds, CMSG_DATA(cmsg), got_fds * sizeof(int));
                        break;
                }
        }
 
        /* Clear out unused file descriptors */
-       while (got_fds < fd_num)
+       while (got_fds < max_fds)
                fds[got_fds++] = -1;
 
        return ret;

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 83d3e632182245bcce2fd9f846a2fba9ce18902e..c1c5f35ff8ef6fbe90bf7db6481410891ca7cfe8 100644 (file)
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1509,7 +1509,7 @@ read_vhost_message(int sockfd, struct VhostUserMsg *msg)
        int ret;
 
        ret = read_fd_message(sockfd, (char *)msg, VHOST_USER_HDR_SIZE,
-               msg->fds, VHOST_MEMORY_MAX_NREGIONS);
+               msg->fds, VHOST_MEMORY_MAX_NREGIONS, &msg->fd_num);
        if (ret <= 0)
                return ret;
 

diff --git a/lib/librte_vhost/vhost_user.h b/lib/librte_vhost/vhost_user.h
index 42166adf23ee3d76b284a72632a505d8e093c4c4..dd0262f8f00e242d699965d0c5083f1c8bd82248 100644 (file)
--- a/lib/librte_vhost/vhost_user.h
+++ b/lib/librte_vhost/vhost_user.h
@@ -132,6 +132,7 @@ typedef struct VhostUserMsg {
                VhostUserVringArea area;
        } payload;
        int fds[VHOST_MEMORY_MAX_NREGIONS];
+       int fd_num;
 } __attribute((packed)) VhostUserMsg;
 
 #define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
@@ -146,7 +147,8 @@ int vhost_user_iotlb_miss(struct virtio_net *dev, uint64_t iova, uint8_t perm);
 int vhost_user_host_notifier_ctrl(int vid, bool enable);
 
 /* socket.c */
-int read_fd_message(int sockfd, char *buf, int buflen, int *fds, int fd_num);
+int read_fd_message(int sockfd, char *buf, int buflen, int *fds, int max_fds,
+               int *fd_num);
 int send_fd_message(int sockfd, char *buf, int buflen, int *fds, int fd_num);
 
 #endif