binutils-gdb/gdb/ser-tcp.c

451 lines
11 KiB
C

/* Serial interface for raw TCP connections on Un*x like systems.
Copyright (C) 1992-2018 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 "filestuff.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 "gdb_sys_time.h"
#ifdef USE_WIN32API
#include <winsock2.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 "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 int tcp_auto_retry = 1;
/* 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 SCB is non-null, 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 (struct serial *scb, 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 (scb)
{
fd_set rset, wset, eset;
FD_ZERO (&rset);
FD_SET (scb->fd, &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 (scb->fd + 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 = gdb_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;
}
/* Open a tcp socket. */
int
net_open (struct serial *scb, const char *name)
{
char hostname[100];
const char *port_str;
int n, port, tmp;
int use_udp;
struct hostent *hostent;
struct sockaddr_in sockaddr;
#ifdef USE_WIN32API
u_long ioarg;
#else
int ioarg;
#endif
unsigned int polls = 0;
use_udp = 0;
if (startswith (name, "udp:"))
{
use_udp = 1;
name = name + 4;
}
else if (startswith (name, "tcp:"))
name = name + 4;
port_str = strchr (name, ':');
if (!port_str)
error (_("net_open: No colon in host name!")); /* Shouldn't ever
happen. */
tmp = std::min (port_str - name, (ptrdiff_t) sizeof hostname - 1);
strncpy (hostname, name, tmp); /* Don't want colon. */
hostname[tmp] = '\000'; /* Tie off host name. */
port = atoi (port_str + 1);
/* Default hostname is localhost. */
if (!hostname[0])
strcpy (hostname, "localhost");
hostent = gethostbyname (hostname);
if (!hostent)
{
fprintf_unfiltered (gdb_stderr, "%s: unknown host\n", hostname);
errno = ENOENT;
return -1;
}
sockaddr.sin_family = PF_INET;
sockaddr.sin_port = htons (port);
memcpy (&sockaddr.sin_addr.s_addr, hostent->h_addr,
sizeof (struct in_addr));
retry:
if (use_udp)
scb->fd = gdb_socket_cloexec (PF_INET, SOCK_DGRAM, 0);
else
scb->fd = gdb_socket_cloexec (PF_INET, SOCK_STREAM, 0);
if (scb->fd == -1)
return -1;
/* Set socket nonblocking. */
ioarg = 1;
ioctl (scb->fd, FIONBIO, &ioarg);
/* Use Non-blocking connect. connect() will return 0 if connected
already. */
n = connect (scb->fd, (struct sockaddr *) &sockaddr, sizeof (sockaddr));
if (n < 0)
{
#ifdef USE_WIN32API
int err = WSAGetLastError();
#else
int err = errno;
#endif
/* Maybe we're waiting for the remote target to become ready to
accept connections. */
if (tcp_auto_retry
#ifdef USE_WIN32API
&& err == WSAECONNREFUSED
#else
&& err == ECONNREFUSED
#endif
&& wait_for_connect (NULL, &polls) >= 0)
{
close (scb->fd);
goto retry;
}
if (
#ifdef USE_WIN32API
/* Under Windows, calling "connect" with a non-blocking socket
results in WSAEWOULDBLOCK, not WSAEINPROGRESS. */
err != WSAEWOULDBLOCK
#else
err != EINPROGRESS
#endif
)
{
errno = err;
net_close (scb);
return -1;
}
/* Looks like we need to wait for the connect. */
do
{
n = wait_for_connect (scb, &polls);
}
while (n == 0);
if (n < 0)
{
net_close (scb);
return -1;
}
}
/* Got something. Is it an error? */
{
int res, err;
socklen_t len;
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 *". */
res = getsockopt (scb->fd, SOL_SOCKET, SO_ERROR, (char *) &err, &len);
if (res < 0 || err)
{
/* Maybe the target still isn't ready to accept the connection. */
if (tcp_auto_retry
#ifdef USE_WIN32API
&& err == WSAECONNREFUSED
#else
&& err == ECONNREFUSED
#endif
&& wait_for_connect (NULL, &polls) >= 0)
{
close (scb->fd);
goto retry;
}
if (err)
errno = err;
net_close (scb);
return -1;
}
}
/* Turn off nonblocking. */
ioarg = 0;
ioctl (scb->fd, FIONBIO, &ioarg);
if (use_udp == 0)
{
/* Disable Nagle algorithm. Needed in some cases. */
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));
}
/* Support for "set tcp" and "show tcp" commands. */
static void
set_tcp_cmd (const char *args, int from_tty)
{
help_list (tcp_set_cmdlist, "set tcp ", all_commands, gdb_stdout);
}
static void
show_tcp_cmd (const char *args, int from_tty)
{
help_list (tcp_show_cmdlist, "show tcp ", all_commands, gdb_stdout);
}
#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)
{
#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_prefix_cmd ("tcp", class_maintenance, set_tcp_cmd, _("\
TCP protocol specific variables\n\
Configure variables specific to remote TCP connections"),
&tcp_set_cmdlist, "set tcp ",
0 /* allow-unknown */, &setlist);
add_prefix_cmd ("tcp", class_maintenance, show_tcp_cmd, _("\
TCP protocol specific variables\n\
Configure variables specific to remote TCP connections"),
&tcp_show_cmdlist, "show tcp ",
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);
}