1 /* Serial interface for raw TCP connections on Un*x like systems.
3 Copyright (C) 1992-2019 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
25 #include "cli/cli-decode.h"
26 #include "cli/cli-setshow.h"
27 #include "common/filestuff.h"
28 #include "common/netstuff.h"
30 #include <sys/types.h>
32 #ifdef HAVE_SYS_FILIO_H
33 #include <sys/filio.h> /* For FIONBIO. */
35 #ifdef HAVE_SYS_IOCTL_H
36 #include <sys/ioctl.h> /* For FIONBIO. */
39 #include "common/gdb_sys_time.h"
42 #if _WIN32_WINNT < 0x0501
44 # define _WIN32_WINNT 0x0501
48 #define ETIMEDOUT WSAETIMEDOUT
50 /* Gnulib defines close too, but gnulib's replacement
51 doesn't call closesocket unless we import the
54 #define close(fd) closesocket (fd)
55 #define ioctl ioctlsocket
57 #include <netinet/in.h>
58 #include <arpa/inet.h>
60 #include <sys/socket.h>
61 #include <netinet/tcp.h>
65 #include "gdb_select.h"
68 #ifndef HAVE_SOCKLEN_T
69 typedef int socklen_t
;
72 /* For "set tcp" and "show tcp". */
74 static struct cmd_list_element
*tcp_set_cmdlist
;
75 static struct cmd_list_element
*tcp_show_cmdlist
;
77 /* Whether to auto-retry refused connections. */
79 static int tcp_auto_retry
= 1;
81 /* Timeout period for connections, in seconds. */
83 static unsigned int tcp_retry_limit
= 15;
85 /* How many times per second to poll deprecated_ui_loop_hook. */
87 #define POLL_INTERVAL 5
89 /* Helper function to wait a while. If SOCK is not -1, wait on its
90 file descriptor. Otherwise just wait on a timeout, updating
91 *POLLS. Returns -1 on timeout or interrupt, otherwise the value of
95 wait_for_connect (int sock
, unsigned int *polls
)
100 /* While we wait for the connect to complete,
101 poll the UI so it can update or the user can
103 if (deprecated_ui_loop_hook
&& deprecated_ui_loop_hook (0))
109 /* Check for timeout. */
110 if (*polls
> tcp_retry_limit
* POLL_INTERVAL
)
116 /* Back off to polling once per second after the first POLL_INTERVAL
118 if (*polls
< POLL_INTERVAL
)
121 t
.tv_usec
= 1000000 / POLL_INTERVAL
;
131 fd_set rset
, wset
, eset
;
134 FD_SET (sock
, &rset
);
138 /* POSIX systems return connection success or failure by signalling
139 wset. Windows systems return success in wset and failure in
142 We must call select here, rather than gdb_select, because
143 the serial structure has not yet been initialized - the
144 MinGW select wrapper will not know that this FD refers
146 n
= select (sock
+ 1, &rset
, &wset
, &eset
, &t
);
149 /* Use gdb_select here, since we have no file descriptors, and on
150 Windows, plain select doesn't work in that case. */
151 n
= gdb_select (0, NULL
, NULL
, NULL
, &t
);
153 /* If we didn't time out, only count it as one poll. */
154 if (n
> 0 || *polls
< POLL_INTERVAL
)
157 (*polls
) += POLL_INTERVAL
;
162 /* Try to connect to the host represented by AINFO. If the connection
163 succeeds, return its socket. Otherwise, return -1 and set ERRNO
164 accordingly. POLLS is used when 'connect' returns EINPROGRESS, and
165 we need to invoke 'wait_for_connect' to obtain the status. */
168 try_connect (const struct addrinfo
*ainfo
, unsigned int *polls
)
170 int sock
= gdb_socket_cloexec (ainfo
->ai_family
, ainfo
->ai_socktype
,
176 /* Set socket nonblocking. */
183 ioctl (sock
, FIONBIO
, &ioarg
);
185 /* Use Non-blocking connect. connect() will return 0 if connected
187 if (connect (sock
, ainfo
->ai_addr
, ainfo
->ai_addrlen
) < 0)
190 int err
= WSAGetLastError();
195 /* If we've got a "connection refused" error, just return
196 -1. The caller will know what to do. */
199 err
== WSAECONNREFUSED
211 /* Any other error (except EINPROGRESS) will be "swallowed"
212 here. We return without specifying a return value, and
213 set errno if the caller wants to inspect what
216 /* Under Windows, calling "connect" with a non-blocking socket
217 results in WSAEWOULDBLOCK, not WSAEINPROGRESS. */
218 err
!= WSAEWOULDBLOCK
229 /* Looks like we need to wait for the connect. */
233 n
= wait_for_connect (sock
, polls
);
238 int saved_errno
= errno
;
240 /* A negative value here means that we either timed out or
241 got interrupted by the user. Just return. */
248 /* Got something. Is it an error? */
250 socklen_t len
= sizeof (err
);
252 /* On Windows, the fourth parameter to getsockopt is a "char *";
253 on UNIX systems it is generally "void *". The cast to "char *"
254 is OK everywhere, since in C++ any data pointer type can be
255 implicitly converted to "void *". */
256 int ret
= getsockopt (sock
, SOL_SOCKET
, SO_ERROR
, (char *) &err
, &len
);
260 int saved_errno
= errno
;
266 else if (ret
== 0 && err
!= 0)
273 /* The connection succeeded. Return the socket. */
277 /* Open a tcp socket. */
280 net_open (struct serial
*scb
, const char *name
)
282 struct addrinfo hint
;
283 struct addrinfo
*ainfo
;
285 memset (&hint
, 0, sizeof (hint
));
286 /* Assume no prefix will be passed, therefore we should use
288 hint
.ai_family
= AF_UNSPEC
;
289 hint
.ai_socktype
= SOCK_STREAM
;
290 hint
.ai_protocol
= IPPROTO_TCP
;
292 parsed_connection_spec parsed
= parse_connection_spec (name
, &hint
);
294 if (parsed
.port_str
.empty ())
295 error (_("Missing port on hostname '%s'"), name
);
297 int r
= getaddrinfo (parsed
.host_str
.c_str (),
298 parsed
.port_str
.c_str (),
303 fprintf_unfiltered (gdb_stderr
, _("%s: cannot resolve name: %s\n"),
304 name
, gai_strerror (r
));
309 scoped_free_addrinfo
free_ainfo (ainfo
);
311 /* Flag to indicate whether we've got a connection refused. It will
312 be true if any of the connections tried was refused. */
313 bool got_connrefused
;
314 /* If a connection succeeeds, SUCCESS_AINFO will point to the
315 'struct addrinfo' that succeed. */
316 struct addrinfo
*success_ainfo
= NULL
;
317 unsigned int polls
= 0;
319 /* Assume the worst. */
324 got_connrefused
= false;
326 for (struct addrinfo
*iter
= ainfo
; iter
!= NULL
; iter
= iter
->ai_next
)
328 /* Iterate over the list of possible addresses to connect
329 to. For each, we'll try to connect and see if it
331 int sock
= try_connect (iter
, &polls
);
335 /* We've gotten a successful connection. Save its
336 'struct addrinfo', the socket, and break. */
337 success_ainfo
= iter
;
343 errno
== WSAECONNREFUSED
345 errno
== ECONNREFUSED
348 got_connrefused
= true;
353 - tcp_auto_retry is true, and
354 - We haven't gotten a connection yet, and
355 - Any of our connection attempts returned with ECONNREFUSED, and
356 - wait_for_connect signals that we can keep going. */
357 while (tcp_auto_retry
358 && success_ainfo
== NULL
360 && wait_for_connect (-1, &polls
) >= 0);
362 if (success_ainfo
== NULL
)
368 /* Turn off nonblocking. */
375 ioctl (scb
->fd
, FIONBIO
, &ioarg
);
377 if (success_ainfo
->ai_protocol
== IPPROTO_TCP
)
379 /* Disable Nagle algorithm. Needed in some cases. */
382 setsockopt (scb
->fd
, IPPROTO_TCP
, TCP_NODELAY
,
383 (char *) &tmp
, sizeof (tmp
));
387 /* If we don't do this, then GDB simply exits
388 when the remote side dies. */
389 signal (SIGPIPE
, SIG_IGN
);
396 net_close (struct serial
*scb
)
406 net_read_prim (struct serial
*scb
, size_t count
)
408 /* Need to cast to silence -Wpointer-sign on MinGW, as Winsock's
409 'recv' takes 'char *' as second argument, while 'scb->buf' is
410 'unsigned char *'. */
411 return recv (scb
->fd
, (char *) scb
->buf
, count
, 0);
415 net_write_prim (struct serial
*scb
, const void *buf
, size_t count
)
417 /* On Windows, the second parameter to send is a "const char *"; on
418 UNIX systems it is generally "const void *". The cast to "const
419 char *" is OK everywhere, since in C++ any data pointer type can
420 be implicitly converted to "const void *". */
421 return send (scb
->fd
, (const char *) buf
, count
, 0);
425 ser_tcp_send_break (struct serial
*scb
)
427 /* Send telnet IAC and BREAK characters. */
428 return (serial_write (scb
, "\377\363", 2));
431 /* Support for "set tcp" and "show tcp" commands. */
434 set_tcp_cmd (const char *args
, int from_tty
)
436 help_list (tcp_set_cmdlist
, "set tcp ", all_commands
, gdb_stdout
);
440 show_tcp_cmd (const char *args
, int from_tty
)
442 help_list (tcp_show_cmdlist
, "show tcp ", all_commands
, gdb_stdout
);
449 static const struct serial_ops tcp_ops
=
457 ser_base_flush_output
,
458 ser_base_flush_input
,
461 ser_base_get_tty_state
,
462 ser_base_copy_tty_state
,
463 ser_base_set_tty_state
,
464 ser_base_print_tty_state
,
465 ser_base_setbaudrate
,
466 ser_base_setstopbits
,
468 ser_base_drain_output
,
474 #endif /* USE_WIN32API */
477 _initialize_ser_tcp (void)
480 /* Do nothing; the TCP serial operations will be initialized in
483 serial_add_interface (&tcp_ops
);
484 #endif /* USE_WIN32API */
486 add_prefix_cmd ("tcp", class_maintenance
, set_tcp_cmd
, _("\
487 TCP protocol specific variables\n\
488 Configure variables specific to remote TCP connections"),
489 &tcp_set_cmdlist
, "set tcp ",
490 0 /* allow-unknown */, &setlist
);
491 add_prefix_cmd ("tcp", class_maintenance
, show_tcp_cmd
, _("\
492 TCP protocol specific variables\n\
493 Configure variables specific to remote TCP connections"),
494 &tcp_show_cmdlist
, "show tcp ",
495 0 /* allow-unknown */, &showlist
);
497 add_setshow_boolean_cmd ("auto-retry", class_obscure
,
498 &tcp_auto_retry
, _("\
499 Set auto-retry on socket connect"), _("\
500 Show auto-retry on socket connect"),
502 &tcp_set_cmdlist
, &tcp_show_cmdlist
);
504 add_setshow_uinteger_cmd ("connect-timeout", class_obscure
,
505 &tcp_retry_limit
, _("\
506 Set timeout limit in seconds for socket connection"), _("\
507 Show timeout limit in seconds for socket connection"), _("\
508 If set to \"unlimited\", GDB will keep attempting to establish a\n\
509 connection forever, unless interrupted with Ctrl-c.\n\
510 The default is 15 seconds."),
512 &tcp_set_cmdlist
, &tcp_show_cmdlist
);