405 lines
11 KiB
C
405 lines
11 KiB
C
/****************************************************************************
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* netutils/telnetd/telnetd_daemon.c
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*
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* Copyright (C) 2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name Gregory Nutt nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <semaphore.h>
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#include <sched.h>
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#include <errno.h>
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#include <debug.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <apps/netutils/telnetd.h>
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#include <apps/netutils/netlib.h>
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#include "telnetd.h"
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Public Data
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****************************************************************************/
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/* This structure is used to passed information to telnet daemon when it
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* started.
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*/
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struct telnetd_common_s g_telnetdcommon;
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: telnetd_daemon
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*
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* Description:
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* This function is the Telnet daemon. It does not return (unless an
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* error occurs).
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*
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* Parameters:
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* Standard task start up arguments.
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*
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* Return:
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* Does not return unless an error occurs.
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*
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****************************************************************************/
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static int telnetd_daemon(int argc, char *argv[])
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{
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FAR struct telnetd_s *daemon;
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struct sockaddr_in myaddr;
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#ifdef CONFIG_NET_SOLINGER
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struct linger ling;
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#endif
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#ifdef CONFIG_SCHED_HAVE_PARENT
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struct sigaction sa;
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sigset_t blockset;
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#endif
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socklen_t addrlen;
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FAR char *devpath;
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pid_t pid;
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int listensd;
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int acceptsd;
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int drvrfd;
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#ifdef CONFIG_NET_HAVE_REUSEADDR
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int optval;
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#endif
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/* Get daemon startup info */
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daemon = g_telnetdcommon.daemon;
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g_telnetdcommon.daemon = NULL;
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sem_post(&g_telnetdcommon.startsem);
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DEBUGASSERT(daemon != NULL);
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#ifdef CONFIG_SCHED_HAVE_PARENT
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/* Call sigaction with the SA_NOCLDWAIT flag so that we do not transform
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* children into "zombies" when they terminate: Child exit status will
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* not be retained.
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*
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* NOTE: If the SA_NOCLDWAIT flag is set when establishing a handler for
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* SIGCHLD, POSIX.1 leaves it unspecified whether a SIGCHLD signal is
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* generated when a child process terminates. On both Linux and NuttX, a
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* SIGCHLD signal will be generated in this case.
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*/
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sa.sa_handler = SIG_IGN;
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sa.sa_flags = SA_NOCLDWAIT;
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if (sigaction(SIGCHLD, &sa, NULL) < 0)
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{
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int errval = errno;
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ndbg("ERROR: sigaction failed: %d\n", errval);
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return -errval;
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}
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/* Block receipt of the SIGCHLD signal */
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sigemptyset(&blockset);
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sigaddset(&blockset, SIGCHLD);
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if (sigprocmask(SIG_BLOCK, &blockset, NULL) < 0)
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{
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int errval = errno;
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ndbg("ERROR: sigprocmask failed: %d\n", errval);
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return -errval;
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}
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#endif /* CONFIG_SCHED_HAVE_PARENT */
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/* Create a new TCP socket to use to listen for connections */
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listensd = socket(PF_INET, SOCK_STREAM, 0);
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if (listensd < 0)
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{
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int errval = errno;
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ndbg("ERROR: socket failure: %d\n", errval);
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return -errval;
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}
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/* Set socket to reuse address */
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#ifdef CONFIG_NET_HAVE_REUSEADDR
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optval = 1;
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if (setsockopt(listensd, SOL_SOCKET, SO_REUSEADDR, (void*)&optval, sizeof(int)) < 0)
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{
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ndbg("ERROR: setsockopt SO_REUSEADDR failure: %d\n", errno);
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goto errout_with_socket;
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}
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#endif
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/* Bind the socket to a local address */
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myaddr.sin_family = AF_INET;
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myaddr.sin_port = daemon->port;
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myaddr.sin_addr.s_addr = INADDR_ANY;
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if (bind(listensd, (struct sockaddr*)&myaddr, sizeof(struct sockaddr_in)) < 0)
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{
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ndbg("ERROR: bind failure: %d\n", errno);
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goto errout_with_socket;
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}
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/* Listen for connections on the bound TCP socket */
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if (listen(listensd, 5) < 0)
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{
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ndbg("ERROR: listen failure %d\n", errno);
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goto errout_with_socket;
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}
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/* Now go silent. Only the lldbg family of debug functions should
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* be used after this point because these do not depend on stdout
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* being available.
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*/
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#ifndef CONFIG_DEBUG
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close(0);
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close(1);
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close(2);
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#endif
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/* Begin accepting connections */
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for (;;)
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{
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nllvdbg("Accepting connections on port %d\n", ntohs(daemon->port));
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addrlen = sizeof(struct sockaddr_in);
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acceptsd = accept(listensd, (struct sockaddr*)&myaddr, &addrlen);
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if (acceptsd < 0)
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{
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/* Accept failed */
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int errval = errno;
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/* Just continue if a signal was received */
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if (errval == EINTR)
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{
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continue;
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}
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else
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{
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nlldbg("ERROR: accept failed: %d\n", errval);
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goto errout_with_socket;
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}
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}
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/* Configure to "linger" until all data is sent when the socket is closed */
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#ifdef CONFIG_NET_SOLINGER
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ling.l_onoff = 1;
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ling.l_linger = 30; /* timeout is seconds */
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if (setsockopt(acceptsd, SOL_SOCKET, SO_LINGER, &ling, sizeof(struct linger)) < 0)
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{
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nlldbg("ERROR: setsockopt failed: %d\n", errno);
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goto errout_with_acceptsd;
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}
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#endif
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/* Create a character device to "wrap" the accepted socket descriptor */
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nllvdbg("Creating the telnet driver\n");
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devpath = telnetd_driver(acceptsd, daemon);
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if (devpath < 0)
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{
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nlldbg("ERROR: telnetd_driver failed\n");
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goto errout_with_acceptsd;
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}
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/* Open the driver */
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nllvdbg("Opening the telnet driver\n");
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drvrfd = open(devpath, O_RDWR);
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if (drvrfd < 0)
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{
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nlldbg("ERROR: Failed to open %s: %d\n", devpath, errno);
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goto errout_with_acceptsd;
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}
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/* We can now free the driver string */
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free(devpath);
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/* Use this driver as stdin, stdout, and stderror */
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(void)dup2(drvrfd, 0);
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(void)dup2(drvrfd, 1);
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(void)dup2(drvrfd, 2);
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/* And we can close our original driver fd */
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if (drvrfd > 2)
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{
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close(drvrfd);
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}
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/* Create a task to handle the connection. The created task
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* will inherit the new stdin, stdout, and stderr.
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*/
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nllvdbg("Starting the telnet session\n");
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pid = task_create("Telnet session", daemon->priority, daemon->stacksize,
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daemon->entry, NULL);
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if (pid < 0)
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{
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nlldbg("ERROR: Failed start the telnet session: %d\n", errno);
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goto errout_with_acceptsd;
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}
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/* Forget about the connection. */
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close(0);
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close(1);
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close(2);
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}
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errout_with_acceptsd:
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close(acceptsd);
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errout_with_socket:
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close(listensd);
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free(daemon);
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return 1;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: telnetd_start
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*
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* Description:
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* Start the telnet daemon.
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*
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* Parameters:
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* config A pointer to a configuration structure that characterizes the
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* telnet daemon. This configuration structure may be defined
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* on the caller's stack because it is not retained by the
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* daemon.
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*
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* Return:
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* The process ID (pid) of the new telnet daemon is returned on
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* success; A negated errno is returned if the daemon was not successfully
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* started.
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*
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****************************************************************************/
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int telnetd_start(FAR struct telnetd_config_s *config)
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{
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FAR struct telnetd_s *daemon;
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pid_t pid;
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int ret;
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/* Allocate a state structure for the new daemon */
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daemon = (FAR struct telnetd_s *)malloc(sizeof(struct telnetd_s));
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if (!daemon)
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{
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return -ENOMEM;
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}
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/* Initialize the daemon structure */
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daemon->port = config->d_port;
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daemon->priority = config->t_priority;
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daemon->stacksize = config->t_stacksize;
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daemon->entry = config->t_entry;
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/* Initialize the common structure if this is the first daemon */
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if (g_telnetdcommon.ndaemons < 1)
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{
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sem_init(&g_telnetdcommon.startsem, 0, 0);
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sem_init(&g_telnetdcommon.exclsem, 0, 1);
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g_telnetdcommon.minor = 0;
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}
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/* Then start the new daemon */
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g_telnetdcommon.daemon = daemon;
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pid = task_create("Telnet daemon", config->d_priority, config->d_stacksize,
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telnetd_daemon, NULL);
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if (pid < 0)
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{
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int errval = errno;
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free(daemon);
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ndbg("ERROR: Failed to start the telnet daemon: %d\n", errval);
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return -errval;
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}
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/* Then wait for the daemon to start and complete the handshake */
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do
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{
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ret = sem_wait(&g_telnetdcommon.startsem);
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/* The only expected error condition is for sem_wait to be awakened by
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* a receipt of a signal.
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*/
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if (ret < 0)
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{
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DEBUGASSERT(errno == -EINTR);
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}
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}
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while (ret < 0);
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/* Return success */
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return pid;
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}
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