net/scm: cleanup scm_detach_fds

Factor out two helpes to keep the code tidy.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/scm.c b/net/core/scm.c
index abfdc85..168b006 100644 (file)
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -277,78 +277,86 @@ void put_cmsg_scm_timestamping(struct msghdr *msg, struct scm_timestamping_inter
 }
 EXPORT_SYMBOL(put_cmsg_scm_timestamping);
 
+static int __scm_install_fd(struct file *file, int __user *ufd, int o_flags)
+{
+       struct socket *sock;
+       int new_fd;
+       int error;
+
+       error = security_file_receive(file);
+       if (error)
+               return error;
+
+       new_fd = get_unused_fd_flags(o_flags);
+       if (new_fd < 0)
+               return new_fd;
+
+       error = put_user(new_fd, ufd);
+       if (error) {
+               put_unused_fd(new_fd);
+               return error;
+       }
+
+       /* Bump the usage count and install the file. */
+       sock = sock_from_file(file, &error);
+       if (sock) {
+               sock_update_netprioidx(&sock->sk->sk_cgrp_data);
+               sock_update_classid(&sock->sk->sk_cgrp_data);
+       }
+       fd_install(new_fd, get_file(file));
+       return error;
+}
+
+static int scm_max_fds(struct msghdr *msg)
+{
+       if (msg->msg_controllen <= sizeof(struct cmsghdr))
+               return 0;
+       return (msg->msg_controllen - sizeof(struct cmsghdr)) / sizeof(int);
+}
+
 void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm)
 {
        struct cmsghdr __user *cm
                = (__force struct cmsghdr __user*)msg->msg_control;
-
-       int fdmax = 0;
-       int fdnum = scm->fp->count;
-       struct file **fp = scm->fp->fp;
-       int __user *cmfptr;
+       int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
+       int fdmax = min_t(int, scm_max_fds(msg), scm->fp->count);
+       int __user *cmsg_data = CMSG_USER_DATA(cm);
        int err = 0, i;
 
-       if (MSG_CMSG_COMPAT & msg->msg_flags) {
+       if (msg->msg_flags & MSG_CMSG_COMPAT) {
                scm_detach_fds_compat(msg, scm);
                return;
        }
 
-       if (msg->msg_controllen > sizeof(struct cmsghdr))
-               fdmax = ((msg->msg_controllen - sizeof(struct cmsghdr))
-                        / sizeof(int));
-
-       if (fdnum < fdmax)
-               fdmax = fdnum;
-
-       for (i=0, cmfptr =(int __user *)CMSG_USER_DATA(cm); i<fdmax;
-            i++, cmfptr++)
-       {
-               struct socket *sock;
-               int new_fd;
-               err = security_file_receive(fp[i]);
+       for (i = 0; i < fdmax; i++) {
+               err = __scm_install_fd(scm->fp->fp[i], cmsg_data + i, o_flags);
                if (err)
                        break;
-               err = get_unused_fd_flags(MSG_CMSG_CLOEXEC & msg->msg_flags
-                                         ? O_CLOEXEC : 0);
-               if (err < 0)
-                       break;
-               new_fd = err;
-               err = put_user(new_fd, cmfptr);
-               if (err) {
-                       put_unused_fd(new_fd);
-                       break;
-               }
-               /* Bump the usage count and install the file. */
-               sock = sock_from_file(fp[i], &err);
-               if (sock) {
-                       sock_update_netprioidx(&sock->sk->sk_cgrp_data);
-                       sock_update_classid(&sock->sk->sk_cgrp_data);
-               }
-               fd_install(new_fd, get_file(fp[i]));
        }
 
-       if (i > 0)
-       {
-               int cmlen = CMSG_LEN(i*sizeof(int));
+       if (i > 0)  {
+               int cmlen = CMSG_LEN(i * sizeof(int));
+
                err = put_user(SOL_SOCKET, &cm->cmsg_level);
                if (!err)
                        err = put_user(SCM_RIGHTS, &cm->cmsg_type);
                if (!err)
                        err = put_user(cmlen, &cm->cmsg_len);
                if (!err) {
-                       cmlen = CMSG_SPACE(i*sizeof(int));
+                       cmlen = CMSG_SPACE(i * sizeof(int));
                        if (msg->msg_controllen < cmlen)
                                cmlen = msg->msg_controllen;
                        msg->msg_control += cmlen;
                        msg->msg_controllen -= cmlen;
                }
        }
-       if (i < fdnum || (fdnum && fdmax <= 0))
+
+       if (i < scm->fp->count || (scm->fp->count && fdmax <= 0))
                msg->msg_flags |= MSG_CTRUNC;
 
        /*
-        * All of the files that fit in the message have had their
-        * usage counts incremented, so we just free the list.
+        * All of the files that fit in the message have had their usage counts
+        * incremented, so we just free the list.
         */
        __scm_destroy(scm);
 }