blob: 2519caa505c0512768a51eea0052d4127b334598 [file] [log] [blame]
/* Serial interface for raw TCP connections on Un*x like systems.
Copyright (C) 1992-2021 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "serial.h"
#include "ser-base.h"
#include "ser-tcp.h"
#include "gdbcmd.h"
#include "cli/cli-decode.h"
#include "cli/cli-setshow.h"
#include "gdbsupport/filestuff.h"
#include "gdbsupport/netstuff.h"
#include <sys/types.h>
#ifdef HAVE_SYS_FILIO_H
#include <sys/filio.h> /* For FIONBIO. */
#endif
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h> /* For FIONBIO. */
#endif
#include "gdbsupport/gdb_sys_time.h"
#ifdef USE_WIN32API
#include <ws2tcpip.h>
#ifndef ETIMEDOUT
#define ETIMEDOUT WSAETIMEDOUT
#endif
/* Gnulib defines close too, but gnulib's replacement
doesn't call closesocket unless we import the
socketlib module. */
#undef close
#define close(fd) closesocket (fd)
#define ioctl ioctlsocket
#else
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/tcp.h>
#endif
#include <signal.h>
#include "gdbsupport/gdb_select.h"
#include <algorithm>
#ifndef HAVE_SOCKLEN_T
typedef int socklen_t;
#endif
/* For "set tcp" and "show tcp". */
static struct cmd_list_element *tcp_set_cmdlist;
static struct cmd_list_element *tcp_show_cmdlist;
/* Whether to auto-retry refused connections. */
static bool tcp_auto_retry = true;
/* Timeout period for connections, in seconds. */
static unsigned int tcp_retry_limit = 15;
/* How many times per second to poll deprecated_ui_loop_hook. */
#define POLL_INTERVAL 5
/* Helper function to wait a while. If SOCK is not -1, wait on its
file descriptor. Otherwise just wait on a timeout, updating
*POLLS. Returns -1 on timeout or interrupt, otherwise the value of
select. */
static int
wait_for_connect (int sock, unsigned int *polls)
{
struct timeval t;
int n;
/* While we wait for the connect to complete,
poll the UI so it can update or the user can
interrupt. */
if (deprecated_ui_loop_hook && deprecated_ui_loop_hook (0))
{
errno = EINTR;
return -1;
}
/* Check for timeout. */
if (*polls > tcp_retry_limit * POLL_INTERVAL)
{
errno = ETIMEDOUT;
return -1;
}
/* Back off to polling once per second after the first POLL_INTERVAL
polls. */
if (*polls < POLL_INTERVAL)
{
t.tv_sec = 0;
t.tv_usec = 1000000 / POLL_INTERVAL;
}
else
{
t.tv_sec = 1;
t.tv_usec = 0;
}
if (sock >= 0)
{
fd_set rset, wset, eset;
FD_ZERO (&rset);
FD_SET (sock, &rset);
wset = rset;
eset = rset;
/* POSIX systems return connection success or failure by signalling
wset. Windows systems return success in wset and failure in
eset.
We must call select here, rather than gdb_select, because
the serial structure has not yet been initialized - the
MinGW select wrapper will not know that this FD refers
to a socket. */
n = select (sock + 1, &rset, &wset, &eset, &t);
}
else
/* Use gdb_select here, since we have no file descriptors, and on
Windows, plain select doesn't work in that case. */
n = interruptible_select (0, NULL, NULL, NULL, &t);
/* If we didn't time out, only count it as one poll. */
if (n > 0 || *polls < POLL_INTERVAL)
(*polls)++;
else
(*polls) += POLL_INTERVAL;
return n;
}
/* Try to connect to the host represented by AINFO. If the connection
succeeds, return its socket. Otherwise, return -1 and set ERRNO
accordingly. POLLS is used when 'connect' returns EINPROGRESS, and
we need to invoke 'wait_for_connect' to obtain the status. */
static int
try_connect (const struct addrinfo *ainfo, unsigned int *polls)
{
int sock = gdb_socket_cloexec (ainfo->ai_family, ainfo->ai_socktype,
ainfo->ai_protocol);
if (sock < 0)
return -1;
/* Set socket nonblocking. */
#ifdef USE_WIN32API
u_long ioarg = 1;
#else
int ioarg = 1;
#endif
ioctl (sock, FIONBIO, &ioarg);
/* Use Non-blocking connect. connect() will return 0 if connected
already. */
if (connect (sock, ainfo->ai_addr, ainfo->ai_addrlen) < 0)
{
#ifdef USE_WIN32API
int err = WSAGetLastError();
#else
int err = errno;
#endif
/* If we've got a "connection refused" error, just return
-1. The caller will know what to do. */
if (
#ifdef USE_WIN32API
err == WSAECONNREFUSED
#else
err == ECONNREFUSED
#endif
)
{
close (sock);
errno = err;
return -1;
}
if (
/* Any other error (except EINPROGRESS) will be "swallowed"
here. We return without specifying a return value, and
set errno if the caller wants to inspect what
happened. */
#ifdef USE_WIN32API
/* Under Windows, calling "connect" with a non-blocking socket
results in WSAEWOULDBLOCK, not WSAEINPROGRESS. */
err != WSAEWOULDBLOCK
#else
err != EINPROGRESS
#endif
)
{
close (sock);
errno = err;
return -1;
}
/* Looks like we need to wait for the connect. */
int n;
do
n = wait_for_connect (sock, polls);
while (n == 0);
if (n < 0)
{
int saved_errno = errno;
/* A negative value here means that we either timed out or
got interrupted by the user. Just return. */
close (sock);
errno = saved_errno;
return -1;
}
}
/* Got something. Is it an error? */
int err;
socklen_t len = sizeof (err);
/* On Windows, the fourth parameter to getsockopt is a "char *";
on UNIX systems it is generally "void *". The cast to "char *"
is OK everywhere, since in C++ any data pointer type can be
implicitly converted to "void *". */
int ret = getsockopt (sock, SOL_SOCKET, SO_ERROR, (char *) &err, &len);
if (ret < 0)
{
int saved_errno = errno;
close (sock);
errno = saved_errno;
return -1;
}
else if (ret == 0 && err != 0)
{
close (sock);
errno = err;
return -1;
}
/* The connection succeeded. Return the socket. */
return sock;
}
/* Open a tcp socket. */
int
net_open (struct serial *scb, const char *name)
{
struct addrinfo hint;
struct addrinfo *ainfo;
memset (&hint, 0, sizeof (hint));
/* Assume no prefix will be passed, therefore we should use
AF_UNSPEC. */
hint.ai_family = AF_UNSPEC;
hint.ai_socktype = SOCK_STREAM;
hint.ai_protocol = IPPROTO_TCP;
parsed_connection_spec parsed = parse_connection_spec (name, &hint);
if (parsed.port_str.empty ())
error (_("Missing port on hostname '%s'"), name);
int r = getaddrinfo (parsed.host_str.c_str (),
parsed.port_str.c_str (),
&hint, &ainfo);
if (r != 0)
{
fprintf_unfiltered (gdb_stderr, _("%s: cannot resolve name: %s\n"),
name, gai_strerror (r));
errno = ENOENT;
return -1;
}
scoped_free_addrinfo free_ainfo (ainfo);
/* Flag to indicate whether we've got a connection refused. It will
be true if any of the connections tried was refused. */
bool got_connrefused;
/* If a connection succeeds, SUCCESS_AINFO will point to the
'struct addrinfo' that succeed. */
struct addrinfo *success_ainfo = NULL;
unsigned int polls = 0;
/* Assume the worst. */
scb->fd = -1;
do
{
got_connrefused = false;
for (addrinfo *iter = ainfo; iter != NULL; iter = iter->ai_next)
{
/* Iterate over the list of possible addresses to connect
to. For each, we'll try to connect and see if it
succeeds. */
int sock = try_connect (iter, &polls);
if (sock >= 0)
{
/* We've gotten a successful connection. Save its
'struct addrinfo', the socket, and break. */
success_ainfo = iter;
scb->fd = sock;
break;
}
else if (
#ifdef USE_WIN32API
errno == WSAECONNREFUSED
#else
errno == ECONNREFUSED
#endif
)
got_connrefused = true;
}
}
/* Just retry if:
- tcp_auto_retry is true, and
- We haven't gotten a connection yet, and
- Any of our connection attempts returned with ECONNREFUSED, and
- wait_for_connect signals that we can keep going. */
while (tcp_auto_retry
&& success_ainfo == NULL
&& got_connrefused
&& wait_for_connect (-1, &polls) >= 0);
if (success_ainfo == NULL)
{
net_close (scb);
return -1;
}
/* Turn off nonblocking. */
#ifdef USE_WIN32API
u_long ioarg = 0;
#else
int ioarg = 0;
#endif
ioctl (scb->fd, FIONBIO, &ioarg);
if (success_ainfo->ai_protocol == IPPROTO_TCP)
{
/* Disable Nagle algorithm. Needed in some cases. */
int tmp = 1;
setsockopt (scb->fd, IPPROTO_TCP, TCP_NODELAY,
(char *) &tmp, sizeof (tmp));
}
#ifdef SIGPIPE
/* If we don't do this, then GDB simply exits
when the remote side dies. */
signal (SIGPIPE, SIG_IGN);
#endif
return 0;
}
void
net_close (struct serial *scb)
{
if (scb->fd == -1)
return;
close (scb->fd);
scb->fd = -1;
}
int
net_read_prim (struct serial *scb, size_t count)
{
/* Need to cast to silence -Wpointer-sign on MinGW, as Winsock's
'recv' takes 'char *' as second argument, while 'scb->buf' is
'unsigned char *'. */
return recv (scb->fd, (char *) scb->buf, count, 0);
}
int
net_write_prim (struct serial *scb, const void *buf, size_t count)
{
/* On Windows, the second parameter to send is a "const char *"; on
UNIX systems it is generally "const void *". The cast to "const
char *" is OK everywhere, since in C++ any data pointer type can
be implicitly converted to "const void *". */
return send (scb->fd, (const char *) buf, count, 0);
}
int
ser_tcp_send_break (struct serial *scb)
{
/* Send telnet IAC and BREAK characters. */
return (serial_write (scb, "\377\363", 2));
}
#ifndef USE_WIN32API
/* The TCP ops. */
static const struct serial_ops tcp_ops =
{
"tcp",
net_open,
net_close,
NULL,
ser_base_readchar,
ser_base_write,
ser_base_flush_output,
ser_base_flush_input,
ser_tcp_send_break,
ser_base_raw,
ser_base_get_tty_state,
ser_base_copy_tty_state,
ser_base_set_tty_state,
ser_base_print_tty_state,
ser_base_setbaudrate,
ser_base_setstopbits,
ser_base_setparity,
ser_base_drain_output,
ser_base_async,
net_read_prim,
net_write_prim
};
#endif /* USE_WIN32API */
void _initialize_ser_tcp ();
void
_initialize_ser_tcp ()
{
#ifdef USE_WIN32API
/* Do nothing; the TCP serial operations will be initialized in
ser-mingw.c. */
#else
serial_add_interface (&tcp_ops);
#endif /* USE_WIN32API */
add_basic_prefix_cmd ("tcp", class_maintenance, _("\
TCP protocol specific variables.\n\
Configure variables specific to remote TCP connections."),
&tcp_set_cmdlist,
0 /* allow-unknown */, &setlist);
add_show_prefix_cmd ("tcp", class_maintenance, _("\
TCP protocol specific variables.\n\
Configure variables specific to remote TCP connections."),
&tcp_show_cmdlist,
0 /* allow-unknown */, &showlist);
add_setshow_boolean_cmd ("auto-retry", class_obscure,
&tcp_auto_retry, _("\
Set auto-retry on socket connect."), _("\
Show auto-retry on socket connect."),
NULL, NULL, NULL,
&tcp_set_cmdlist, &tcp_show_cmdlist);
add_setshow_uinteger_cmd ("connect-timeout", class_obscure,
&tcp_retry_limit, _("\
Set timeout limit in seconds for socket connection."), _("\
Show timeout limit in seconds for socket connection."), _("\
If set to \"unlimited\", GDB will keep attempting to establish a\n\
connection forever, unless interrupted with Ctrl-c.\n\
The default is 15 seconds."),
NULL, NULL,
&tcp_set_cmdlist, &tcp_show_cmdlist);
}