When accept returns EMFILE or ENFILE,
    it also drops a  pending connection.
    You may argue that is corner case, but still
    it can be avoided by code adjustment.

    The example program is attached.

--- linux-2.6.9/net/socket.c    Mon Oct 18 14:53:50 2004
+++ linux/net/socket.c          Mon Nov 15 16:09:37 2004
@@ -362,7 +362,7 @@
  *     but we take care of internal coherence yet.
  */

-int sock_map_fd(struct socket *sock)
+int sock_create_fd(struct socket *sock, struct file **filep)
 {
        int fd;
        struct qstr this;
@@ -372,6 +372,7 @@
         *      Find a file descriptor suitable for return to the user.
         */

+       *filep = NULL;
        fd = get_unused_fd();
        if (fd >= 0) {
                struct file *file = get_empty_filp();
@@ -404,13 +405,36 @@
                file->f_mode = FMODE_READ | FMODE_WRITE;
                file->f_flags = O_RDWR;
                file->f_pos = 0;
-               fd_install(fd, file);
+               *filep = file;
        }

 out:
        return fd;
 }

+static inline void sock_install_fd(struct sock *sock, int fd, struct
file *file)
+{
+       fd_install(fd, file);
+}
+
+static inline void sock_release_fd(struct sock *sock, int fd, struct
file *file)
+{
+       fput(file);
+       put_unused_fd(fd);
+}
+
+int sock_map_fd(struct sock *sock)
+{
+       int fd;
+       struct file *file;
+
+       fd = sock_create_fd(sock, &file);
+       if (fd >= 0)
+               sock_install_fd(sock, fd, file);
+
+       return fd;
+}
+
 /**
  *     sockfd_lookup   -       Go from a file number to its socket slot

  *     @fd: file handle
@@ -1349,6 +1373,8 @@
        struct socket *sock, *newsock;
        int err, len;
        char address[MAX_SOCK_ADDR];
+       int newfd;
+       struct file *newfile;

        sock = sockfd_lookup(fd, &err);
        if (!sock)
@@ -1371,24 +1397,29 @@
         */
        __module_get(newsock->ops->owner);

+       newfd = sock_create_fd(newsock, &newfile);
+       if (newfd < 0) {
+               err = newfd;
+               goto out_release;
+       }
+
        err = sock->ops->accept(sock, newsock, sock->file->f_flags);
        if (err < 0)
-               goto out_release;
+               goto out_fd;

        if (upeer_sockaddr) {
                if(newsock->ops->getname(newsock, (struct sockaddr
*)address, &len, 2)<0) {
                        err = -ECONNABORTED;
-                       goto out_release;
+                       goto out_fd;
                }
                err = move_addr_to_user(address, len, upeer_sockaddr,
upeer_addrlen);
                if (err < 0)
-                       goto out_release;
+                       goto out_fd;
        }

        /* File flags are not inherited via accept() unlike another
OSes. */

-       if ((err = sock_map_fd(newsock)) < 0)
-               goto out_release;
+       sock_install_fd(newsock, newfd, newfile);

        security_socket_post_accept(sock, newsock);

@@ -1396,6 +1427,8 @@
        sockfd_put(sock);
 out:
        return err;
+out_fd:
+       sock_release_fd(newsock, newfd, newfile);
 out_release:
        sock_release(newsock);
        goto out_put;