1 /* Serial interface for raw TCP connections on Un*x like systems.
3 Copyright (C) 1992-2024 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 "gdbsupport/filestuff.h"
28 #include "gdbsupport/netstuff.h"
30 #include <sys/types.h>
32 #ifdef HAVE_SYS_FILIO_H
33 #include <sys/filio.h>
35 #ifdef HAVE_SYS_IOCTL_H
36 #include <sys/ioctl.h>
39 #include "gdbsupport/gdb_sys_time.h"
44 #define ETIMEDOUT WSAETIMEDOUT
46 /* Gnulib defines close too, but gnulib's replacement
47 doesn't call closesocket unless we import the
50 #define close(fd) closesocket (fd)
51 #define ioctl ioctlsocket
53 #include <netinet/in.h>
54 #include <arpa/inet.h>
56 #include <sys/socket.h>
57 #include <netinet/tcp.h>
61 #include "gdbsupport/gdb_select.h"
64 #ifndef HAVE_SOCKLEN_T
65 typedef int socklen_t
;
68 /* For "set tcp" and "show tcp". */
70 static struct cmd_list_element
*tcp_set_cmdlist
;
71 static struct cmd_list_element
*tcp_show_cmdlist
;
73 /* Whether to auto-retry refused connections. */
75 static bool tcp_auto_retry
= true;
77 /* Timeout period for connections, in seconds. */
79 static unsigned int tcp_retry_limit
= 15;
81 /* How many times per second to poll deprecated_ui_loop_hook. */
83 #define POLL_INTERVAL 5
85 /* Helper function to wait a while. If SOCK is not -1, wait on its
86 file descriptor. Otherwise just wait on a timeout, updating
87 *POLLS. Returns -1 on timeout or interrupt and set OUT_ERROR,
88 otherwise the value of select. */
91 wait_for_connect (int sock
, unsigned int *polls
, ULONGEST
*out_error
)
96 /* While we wait for the connect to complete,
97 poll the UI so it can update or the user can
99 if (deprecated_ui_loop_hook
&& deprecated_ui_loop_hook (0))
105 /* Check for timeout. */
106 if (*polls
> tcp_retry_limit
* POLL_INTERVAL
)
108 *out_error
= ETIMEDOUT
;
112 /* Back off to polling once per second after the first POLL_INTERVAL
114 if (*polls
< POLL_INTERVAL
)
117 t
.tv_usec
= 1000000 / POLL_INTERVAL
;
127 fd_set rset
, wset
, eset
;
130 FD_SET (sock
, &rset
);
134 /* POSIX systems return connection success or failure by signalling
135 wset. Windows systems return success in wset and failure in
138 We must call select here, rather than gdb_select, because
139 the serial structure has not yet been initialized - the
140 MinGW select wrapper will not know that this FD refers
142 n
= select (sock
+ 1, &rset
, &wset
, &eset
, &t
);
145 /* Use gdb_select here, since we have no file descriptors, and on
146 Windows, plain select doesn't work in that case. */
147 n
= interruptible_select (0, NULL
, NULL
, NULL
, &t
);
149 /* If we didn't time out, only count it as one poll. */
150 if (n
> 0 || *polls
< POLL_INTERVAL
)
153 (*polls
) += POLL_INTERVAL
;
158 /* A helper to get the error number for either Windows or POSIX. */
163 return WSAGetLastError ();
169 /* Try to connect to the host represented by AINFO. If the connection
170 succeeds, return its socket. Otherwise, return -1 and set OUT_ERROR
171 accordingly. POLLS is used when 'connect' returns EINPROGRESS, and
172 we need to invoke 'wait_for_connect' to obtain the status. */
175 try_connect (const struct addrinfo
*ainfo
, unsigned int *polls
,
178 int sock
= gdb_socket_cloexec (ainfo
->ai_family
, ainfo
->ai_socktype
,
183 *out_error
= get_error ();
187 /* Set socket nonblocking. */
194 ioctl (sock
, FIONBIO
, &ioarg
);
196 /* Use Non-blocking connect. connect() will return 0 if connected
198 if (connect (sock
, ainfo
->ai_addr
, ainfo
->ai_addrlen
) < 0)
200 ULONGEST err
= get_error ();
202 /* If we've got a "connection refused" error, just return
203 -1. The caller will know what to do. */
206 err
== WSAECONNREFUSED
218 /* Any other error (except EINPROGRESS) will be "swallowed"
219 here. We return without specifying a return value, and
220 set errno if the caller wants to inspect what
223 /* Under Windows, calling "connect" with a non-blocking socket
224 results in WSAEWOULDBLOCK, not WSAEINPROGRESS. */
225 err
!= WSAEWOULDBLOCK
236 /* Looks like we need to wait for the connect. */
240 n
= wait_for_connect (sock
, polls
, out_error
);
245 /* A negative value here means that we either timed out or
246 got interrupted by the user. Just return. */
248 /* OUT_ERROR was set by wait_for_connect, above. */
253 /* Got something. Is it an error? */
255 socklen_t len
= sizeof (err
);
257 /* On Windows, the fourth parameter to getsockopt is a "char *";
258 on UNIX systems it is generally "void *". The cast to "char *"
259 is OK everywhere, since in C++ any data pointer type can be
260 implicitly converted to "void *". */
261 int ret
= getsockopt (sock
, SOL_SOCKET
, SO_ERROR
, (char *) &err
, &len
);
265 *out_error
= get_error ();
269 else if (ret
== 0 && err
!= 0)
276 /* The connection succeeded. Return the socket. */
280 /* Open a tcp socket. */
283 net_open (struct serial
*scb
, const char *name
)
285 struct addrinfo hint
;
286 struct addrinfo
*ainfo
;
288 memset (&hint
, 0, sizeof (hint
));
289 /* Assume no prefix will be passed, therefore we should use
291 hint
.ai_family
= AF_UNSPEC
;
292 hint
.ai_socktype
= SOCK_STREAM
;
293 hint
.ai_protocol
= IPPROTO_TCP
;
295 parsed_connection_spec parsed
= parse_connection_spec (name
, &hint
);
297 if (parsed
.port_str
.empty ())
298 error (_("Missing port on hostname '%s'"), name
);
300 int r
= getaddrinfo (parsed
.host_str
.c_str (),
301 parsed
.port_str
.c_str (),
305 error (_("%s: cannot resolve name: %s\n"), name
, gai_strerror (r
));
307 scoped_free_addrinfo
free_ainfo (ainfo
);
309 /* Flag to indicate whether we've got a connection refused. It will
310 be true if any of the connections tried was refused. */
311 bool got_connrefused
;
312 /* If a connection succeeds, SUCCESS_AINFO will point to the
313 'struct addrinfo' that succeed. */
314 struct addrinfo
*success_ainfo
= NULL
;
315 unsigned int polls
= 0;
316 ULONGEST last_error
= 0;
318 /* Assume the worst. */
323 got_connrefused
= false;
325 for (addrinfo
*iter
= ainfo
; iter
!= NULL
; iter
= iter
->ai_next
)
327 /* Iterate over the list of possible addresses to connect
328 to. For each, we'll try to connect and see if it
330 int sock
= try_connect (iter
, &polls
, &last_error
);
334 /* We've gotten a successful connection. Save its
335 'struct addrinfo', the socket, and break. */
336 success_ainfo
= iter
;
342 last_error
== WSAECONNREFUSED
344 last_error
== ECONNREFUSED
347 got_connrefused
= true;
352 - tcp_auto_retry is true, and
353 - We haven't gotten a connection yet, and
354 - Any of our connection attempts returned with ECONNREFUSED, and
355 - wait_for_connect signals that we can keep going. */
356 while (tcp_auto_retry
357 && success_ainfo
== NULL
359 && wait_for_connect (-1, &polls
, &last_error
) >= 0);
361 if (success_ainfo
== NULL
)
365 throw_winerror_with_name (_("could not connect"), last_error
);
367 perror_with_name (_("could not connect"), last_error
);
371 /* Turn off nonblocking. */
378 ioctl (scb
->fd
, FIONBIO
, &ioarg
);
380 if (success_ainfo
->ai_protocol
== IPPROTO_TCP
)
382 /* Disable Nagle algorithm. Needed in some cases. */
385 setsockopt (scb
->fd
, IPPROTO_TCP
, TCP_NODELAY
,
386 (char *) &tmp
, sizeof (tmp
));
390 /* If we don't do this, then GDB simply exits
391 when the remote side dies. */
392 signal (SIGPIPE
, SIG_IGN
);
397 net_close (struct serial
*scb
)
407 net_read_prim (struct serial
*scb
, size_t count
)
409 /* Need to cast to silence -Wpointer-sign on MinGW, as Winsock's
410 'recv' takes 'char *' as second argument, while 'scb->buf' is
411 'unsigned char *'. */
412 int result
= recv (scb
->fd
, (char *) scb
->buf
, count
, 0);
413 if (result
== -1 && errno
!= EINTR
)
414 perror_with_name ("error while reading");
419 net_write_prim (struct serial
*scb
, const void *buf
, size_t count
)
421 /* On Windows, the second parameter to send is a "const char *"; on
422 UNIX systems it is generally "const void *". The cast to "const
423 char *" is OK everywhere, since in C++ any data pointer type can
424 be implicitly converted to "const void *". */
425 int result
= send (scb
->fd
, (const char *) buf
, count
, 0);
426 if (result
== -1 && errno
!= EINTR
)
427 perror_with_name ("error while writing");
432 ser_tcp_send_break (struct serial
*scb
)
434 /* Send telnet IAC and BREAK characters. */
435 serial_write (scb
, "\377\363", 2);
442 static const struct serial_ops tcp_ops
=
450 ser_base_flush_output
,
451 ser_base_flush_input
,
454 ser_base_get_tty_state
,
455 ser_base_copy_tty_state
,
456 ser_base_set_tty_state
,
457 ser_base_print_tty_state
,
458 ser_base_setbaudrate
,
459 ser_base_setstopbits
,
461 ser_base_drain_output
,
467 #endif /* USE_WIN32API */
469 void _initialize_ser_tcp ();
471 _initialize_ser_tcp ()
474 /* Do nothing; the TCP serial operations will be initialized in
477 serial_add_interface (&tcp_ops
);
478 #endif /* USE_WIN32API */
480 add_setshow_prefix_cmd ("tcp", class_maintenance
,
482 TCP protocol specific variables.\n\
483 Configure variables specific to remote TCP connections."),
485 TCP protocol specific variables.\n\
486 Configure variables specific to remote TCP connections."),
487 &tcp_set_cmdlist
, &tcp_show_cmdlist
,
488 &setlist
, &showlist
);
490 add_setshow_boolean_cmd ("auto-retry", class_obscure
,
491 &tcp_auto_retry
, _("\
492 Set auto-retry on socket connect."), _("\
493 Show auto-retry on socket connect."),
495 &tcp_set_cmdlist
, &tcp_show_cmdlist
);
497 add_setshow_uinteger_cmd ("connect-timeout", class_obscure
,
498 &tcp_retry_limit
, _("\
499 Set timeout limit in seconds for socket connection."), _("\
500 Show timeout limit in seconds for socket connection."), _("\
501 If set to \"unlimited\", GDB will keep attempting to establish a\n\
502 connection forever, unless interrupted with Ctrl-c.\n\
503 The default is 15 seconds."),
505 &tcp_set_cmdlist
, &tcp_show_cmdlist
);