514 lines
12 KiB
C
514 lines
12 KiB
C
/* Serial interface for raw TCP connections on Un*x like systems.
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Copyright (C) 1992-2019 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "serial.h"
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#include "ser-base.h"
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#include "ser-tcp.h"
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#include "gdbcmd.h"
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#include "cli/cli-decode.h"
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#include "cli/cli-setshow.h"
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#include "common/filestuff.h"
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#include "common/netstuff.h"
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#include <sys/types.h>
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#ifdef HAVE_SYS_FILIO_H
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#include <sys/filio.h> /* For FIONBIO. */
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#endif
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#ifdef HAVE_SYS_IOCTL_H
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#include <sys/ioctl.h> /* For FIONBIO. */
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#endif
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#include "common/gdb_sys_time.h"
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#ifdef USE_WIN32API
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#if _WIN32_WINNT < 0x0501
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# undef _WIN32_WINNT
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# define _WIN32_WINNT 0x0501
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#endif
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#include <ws2tcpip.h>
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#ifndef ETIMEDOUT
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#define ETIMEDOUT WSAETIMEDOUT
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#endif
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/* Gnulib defines close too, but gnulib's replacement
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doesn't call closesocket unless we import the
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socketlib module. */
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#undef close
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#define close(fd) closesocket (fd)
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#define ioctl ioctlsocket
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#else
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <sys/socket.h>
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#include <netinet/tcp.h>
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#endif
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#include <signal.h>
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#include "gdb_select.h"
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#include <algorithm>
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#ifndef HAVE_SOCKLEN_T
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typedef int socklen_t;
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#endif
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/* For "set tcp" and "show tcp". */
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static struct cmd_list_element *tcp_set_cmdlist;
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static struct cmd_list_element *tcp_show_cmdlist;
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/* Whether to auto-retry refused connections. */
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static int tcp_auto_retry = 1;
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/* Timeout period for connections, in seconds. */
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static unsigned int tcp_retry_limit = 15;
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/* How many times per second to poll deprecated_ui_loop_hook. */
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#define POLL_INTERVAL 5
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/* Helper function to wait a while. If SOCK is not -1, wait on its
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file descriptor. Otherwise just wait on a timeout, updating
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*POLLS. Returns -1 on timeout or interrupt, otherwise the value of
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select. */
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static int
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wait_for_connect (int sock, unsigned int *polls)
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{
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struct timeval t;
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int n;
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/* While we wait for the connect to complete,
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poll the UI so it can update or the user can
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interrupt. */
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if (deprecated_ui_loop_hook && deprecated_ui_loop_hook (0))
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{
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errno = EINTR;
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return -1;
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}
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/* Check for timeout. */
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if (*polls > tcp_retry_limit * POLL_INTERVAL)
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{
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errno = ETIMEDOUT;
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return -1;
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}
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/* Back off to polling once per second after the first POLL_INTERVAL
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polls. */
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if (*polls < POLL_INTERVAL)
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{
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t.tv_sec = 0;
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t.tv_usec = 1000000 / POLL_INTERVAL;
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}
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else
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{
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t.tv_sec = 1;
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t.tv_usec = 0;
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}
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if (sock >= 0)
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{
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fd_set rset, wset, eset;
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FD_ZERO (&rset);
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FD_SET (sock, &rset);
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wset = rset;
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eset = rset;
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/* POSIX systems return connection success or failure by signalling
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wset. Windows systems return success in wset and failure in
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eset.
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We must call select here, rather than gdb_select, because
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the serial structure has not yet been initialized - the
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MinGW select wrapper will not know that this FD refers
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to a socket. */
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n = select (sock + 1, &rset, &wset, &eset, &t);
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}
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else
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/* Use gdb_select here, since we have no file descriptors, and on
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Windows, plain select doesn't work in that case. */
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n = gdb_select (0, NULL, NULL, NULL, &t);
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/* If we didn't time out, only count it as one poll. */
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if (n > 0 || *polls < POLL_INTERVAL)
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(*polls)++;
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else
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(*polls) += POLL_INTERVAL;
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return n;
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}
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/* Try to connect to the host represented by AINFO. If the connection
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succeeds, return its socket. Otherwise, return -1 and set ERRNO
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accordingly. POLLS is used when 'connect' returns EINPROGRESS, and
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we need to invoke 'wait_for_connect' to obtain the status. */
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static int
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try_connect (const struct addrinfo *ainfo, unsigned int *polls)
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{
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int sock = gdb_socket_cloexec (ainfo->ai_family, ainfo->ai_socktype,
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ainfo->ai_protocol);
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if (sock < 0)
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return -1;
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/* Set socket nonblocking. */
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#ifdef USE_WIN32API
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u_long ioarg = 1;
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#else
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int ioarg = 1;
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#endif
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ioctl (sock, FIONBIO, &ioarg);
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/* Use Non-blocking connect. connect() will return 0 if connected
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already. */
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if (connect (sock, ainfo->ai_addr, ainfo->ai_addrlen) < 0)
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{
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#ifdef USE_WIN32API
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int err = WSAGetLastError();
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#else
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int err = errno;
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#endif
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/* If we've got a "connection refused" error, just return
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-1. The caller will know what to do. */
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if (
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#ifdef USE_WIN32API
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err == WSAECONNREFUSED
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#else
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err == ECONNREFUSED
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#endif
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)
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{
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close (sock);
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errno = err;
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return -1;
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}
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if (
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/* Any other error (except EINPROGRESS) will be "swallowed"
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here. We return without specifying a return value, and
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set errno if the caller wants to inspect what
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happened. */
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#ifdef USE_WIN32API
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/* Under Windows, calling "connect" with a non-blocking socket
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results in WSAEWOULDBLOCK, not WSAEINPROGRESS. */
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err != WSAEWOULDBLOCK
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#else
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err != EINPROGRESS
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#endif
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)
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{
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close (sock);
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errno = err;
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return -1;
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}
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/* Looks like we need to wait for the connect. */
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int n;
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do
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n = wait_for_connect (sock, polls);
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while (n == 0);
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if (n < 0)
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{
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int saved_errno = errno;
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/* A negative value here means that we either timed out or
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got interrupted by the user. Just return. */
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close (sock);
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errno = saved_errno;
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return -1;
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}
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}
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/* Got something. Is it an error? */
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int err;
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socklen_t len = sizeof (err);
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/* On Windows, the fourth parameter to getsockopt is a "char *";
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on UNIX systems it is generally "void *". The cast to "char *"
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is OK everywhere, since in C++ any data pointer type can be
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implicitly converted to "void *". */
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int ret = getsockopt (sock, SOL_SOCKET, SO_ERROR, (char *) &err, &len);
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if (ret < 0)
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{
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int saved_errno = errno;
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close (sock);
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errno = saved_errno;
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return -1;
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}
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else if (ret == 0 && err != 0)
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{
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close (sock);
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errno = err;
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return -1;
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}
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/* The connection succeeded. Return the socket. */
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return sock;
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}
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/* Open a tcp socket. */
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int
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net_open (struct serial *scb, const char *name)
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{
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struct addrinfo hint;
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struct addrinfo *ainfo;
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memset (&hint, 0, sizeof (hint));
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/* Assume no prefix will be passed, therefore we should use
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AF_UNSPEC. */
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hint.ai_family = AF_UNSPEC;
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hint.ai_socktype = SOCK_STREAM;
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hint.ai_protocol = IPPROTO_TCP;
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parsed_connection_spec parsed = parse_connection_spec (name, &hint);
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if (parsed.port_str.empty ())
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error (_("Missing port on hostname '%s'"), name);
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int r = getaddrinfo (parsed.host_str.c_str (),
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parsed.port_str.c_str (),
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&hint, &ainfo);
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if (r != 0)
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{
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fprintf_unfiltered (gdb_stderr, _("%s: cannot resolve name: %s\n"),
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name, gai_strerror (r));
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errno = ENOENT;
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return -1;
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}
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scoped_free_addrinfo free_ainfo (ainfo);
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/* Flag to indicate whether we've got a connection refused. It will
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be true if any of the connections tried was refused. */
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bool got_connrefused;
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/* If a connection succeeeds, SUCCESS_AINFO will point to the
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'struct addrinfo' that succeed. */
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struct addrinfo *success_ainfo = NULL;
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unsigned int polls = 0;
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/* Assume the worst. */
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scb->fd = -1;
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do
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{
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got_connrefused = false;
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for (struct addrinfo *iter = ainfo; iter != NULL; iter = iter->ai_next)
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{
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/* Iterate over the list of possible addresses to connect
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to. For each, we'll try to connect and see if it
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succeeds. */
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int sock = try_connect (iter, &polls);
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if (sock >= 0)
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{
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/* We've gotten a successful connection. Save its
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'struct addrinfo', the socket, and break. */
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success_ainfo = iter;
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scb->fd = sock;
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break;
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}
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else if (
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#ifdef USE_WIN32API
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errno == WSAECONNREFUSED
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#else
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errno == ECONNREFUSED
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#endif
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)
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got_connrefused = true;
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}
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}
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/* Just retry if:
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- tcp_auto_retry is true, and
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- We haven't gotten a connection yet, and
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- Any of our connection attempts returned with ECONNREFUSED, and
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- wait_for_connect signals that we can keep going. */
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while (tcp_auto_retry
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&& success_ainfo == NULL
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&& got_connrefused
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&& wait_for_connect (-1, &polls) >= 0);
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if (success_ainfo == NULL)
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{
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net_close (scb);
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return -1;
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}
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/* Turn off nonblocking. */
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#ifdef USE_WIN32API
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u_long ioarg = 0;
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#else
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int ioarg = 0;
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#endif
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ioctl (scb->fd, FIONBIO, &ioarg);
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if (success_ainfo->ai_protocol == IPPROTO_TCP)
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{
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/* Disable Nagle algorithm. Needed in some cases. */
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int tmp = 1;
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setsockopt (scb->fd, IPPROTO_TCP, TCP_NODELAY,
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(char *) &tmp, sizeof (tmp));
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}
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#ifdef SIGPIPE
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/* If we don't do this, then GDB simply exits
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when the remote side dies. */
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signal (SIGPIPE, SIG_IGN);
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#endif
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return 0;
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}
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void
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net_close (struct serial *scb)
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{
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if (scb->fd == -1)
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return;
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close (scb->fd);
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scb->fd = -1;
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}
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int
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net_read_prim (struct serial *scb, size_t count)
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{
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/* Need to cast to silence -Wpointer-sign on MinGW, as Winsock's
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'recv' takes 'char *' as second argument, while 'scb->buf' is
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'unsigned char *'. */
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return recv (scb->fd, (char *) scb->buf, count, 0);
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}
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int
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net_write_prim (struct serial *scb, const void *buf, size_t count)
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{
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/* On Windows, the second parameter to send is a "const char *"; on
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UNIX systems it is generally "const void *". The cast to "const
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char *" is OK everywhere, since in C++ any data pointer type can
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be implicitly converted to "const void *". */
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return send (scb->fd, (const char *) buf, count, 0);
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}
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int
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ser_tcp_send_break (struct serial *scb)
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{
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/* Send telnet IAC and BREAK characters. */
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return (serial_write (scb, "\377\363", 2));
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}
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/* Support for "set tcp" and "show tcp" commands. */
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static void
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set_tcp_cmd (const char *args, int from_tty)
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{
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help_list (tcp_set_cmdlist, "set tcp ", all_commands, gdb_stdout);
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}
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static void
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show_tcp_cmd (const char *args, int from_tty)
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{
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help_list (tcp_show_cmdlist, "show tcp ", all_commands, gdb_stdout);
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}
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#ifndef USE_WIN32API
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/* The TCP ops. */
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static const struct serial_ops tcp_ops =
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{
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"tcp",
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net_open,
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net_close,
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NULL,
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ser_base_readchar,
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ser_base_write,
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ser_base_flush_output,
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ser_base_flush_input,
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ser_tcp_send_break,
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ser_base_raw,
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ser_base_get_tty_state,
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ser_base_copy_tty_state,
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ser_base_set_tty_state,
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ser_base_print_tty_state,
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ser_base_setbaudrate,
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ser_base_setstopbits,
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ser_base_setparity,
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ser_base_drain_output,
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ser_base_async,
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net_read_prim,
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net_write_prim
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};
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#endif /* USE_WIN32API */
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void
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_initialize_ser_tcp (void)
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{
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#ifdef USE_WIN32API
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/* Do nothing; the TCP serial operations will be initialized in
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ser-mingw.c. */
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#else
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serial_add_interface (&tcp_ops);
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#endif /* USE_WIN32API */
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add_prefix_cmd ("tcp", class_maintenance, set_tcp_cmd, _("\
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TCP protocol specific variables\n\
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Configure variables specific to remote TCP connections"),
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&tcp_set_cmdlist, "set tcp ",
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0 /* allow-unknown */, &setlist);
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add_prefix_cmd ("tcp", class_maintenance, show_tcp_cmd, _("\
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TCP protocol specific variables\n\
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Configure variables specific to remote TCP connections"),
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&tcp_show_cmdlist, "show tcp ",
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0 /* allow-unknown */, &showlist);
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add_setshow_boolean_cmd ("auto-retry", class_obscure,
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&tcp_auto_retry, _("\
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Set auto-retry on socket connect"), _("\
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Show auto-retry on socket connect"),
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NULL, NULL, NULL,
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&tcp_set_cmdlist, &tcp_show_cmdlist);
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add_setshow_uinteger_cmd ("connect-timeout", class_obscure,
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&tcp_retry_limit, _("\
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Set timeout limit in seconds for socket connection"), _("\
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Show timeout limit in seconds for socket connection"), _("\
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If set to \"unlimited\", GDB will keep attempting to establish a\n\
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connection forever, unless interrupted with Ctrl-c.\n\
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The default is 15 seconds."),
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NULL, NULL,
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&tcp_set_cmdlist, &tcp_show_cmdlist);
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}
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