gdb/ser-tcp.c

   1 /* Serial interface for raw TCP connections on Un*x like systems.
   2
   3    Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2001, 2005, 2006,
   4    2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "serial.h"
  23 #include "ser-base.h"
  24 #include "ser-tcp.h"
  25 #include "gdbcmd.h"
  26 #include "cli/cli-decode.h"
  27 #include "cli/cli-setshow.h"
  28
  29 #include <sys/types.h>
  30
  31 #ifdef HAVE_SYS_FILIO_H
  32 #include <sys/filio.h>  /* For FIONBIO.  */
  33 #endif
  34 #ifdef HAVE_SYS_IOCTL_H
  35 #include <sys/ioctl.h>  /* For FIONBIO.  */
  36 #endif
  37
  38 #include <sys/time.h>
  39
  40 #ifdef USE_WIN32API
  41 #include <winsock2.h>
  42 #define ETIMEDOUT WSAETIMEDOUT
  43 #define close(fd) closesocket (fd)
  44 #define ioctl ioctlsocket
  45 #else
  46 #include <netinet/in.h>
  47 #include <arpa/inet.h>
  48 #include <netdb.h>
  49 #include <sys/socket.h>
  50 #include <netinet/tcp.h>
  51 #endif
  52
  53 #include <signal.h>
  54 #include "gdb_string.h"
  55 #include "gdb_select.h"
  56
  57 #ifndef HAVE_SOCKLEN_T
  58 typedef int socklen_t;
  59 #endif
  60
  61 void _initialize_ser_tcp (void);
  62
  63 /* For "set tcp" and "show tcp".  */
  64
  65 static struct cmd_list_element *tcp_set_cmdlist;
  66 static struct cmd_list_element *tcp_show_cmdlist;
  67
  68 /* Whether to auto-retry refused connections.  */
  69
  70 static int tcp_auto_retry = 1;
  71
  72 /* Timeout period for connections, in seconds.  */
  73
  74 static int tcp_retry_limit = 15;
  75
  76 /* How many times per second to poll deprecated_ui_loop_hook.  */
  77
  78 #define POLL_INTERVAL 5
  79
  80 /* Helper function to wait a while.  If SCB is non-null, wait on its
  81    file descriptor.  Otherwise just wait on a timeout, updating *POLLS.
  82    Returns -1 on timeout or interrupt, otherwise the value of select.  */
  83
  84 static int
  85 wait_for_connect (struct serial *scb, int *polls)
  86 {
  87   struct timeval t;
  88   int n;
  89
  90   /* While we wait for the connect to complete,
  91      poll the UI so it can update or the user can
  92      interrupt.  */
  93   if (deprecated_ui_loop_hook && deprecated_ui_loop_hook (0))
  94     {
  95       errno = EINTR;
  96       return -1;
  97     }
  98
  99   /* Check for timeout.  */
 100   if (*polls > tcp_retry_limit * POLL_INTERVAL)
 101     {
 102       errno = ETIMEDOUT;
 103       return -1;
 104     }
 105
 106   /* Back off to polling once per second after the first POLL_INTERVAL
 107      polls.  */
 108   if (*polls < POLL_INTERVAL)
 109     {
 110       t.tv_sec = 0;
 111       t.tv_usec = 1000000 / POLL_INTERVAL;
 112     }
 113   else
 114     {
 115       t.tv_sec = 1;
 116       t.tv_usec = 0;
 117     }
 118
 119   if (scb)
 120     {
 121       fd_set rset, wset, eset;
 122
 123       FD_ZERO (&rset);
 124       FD_SET (scb->fd, &rset);
 125       wset = rset;
 126       eset = rset;
 127
 128       /* POSIX systems return connection success or failure by signalling
 129          wset.  Windows systems return success in wset and failure in
 130          eset.
 131
 132          We must call select here, rather than gdb_select, because
 133          the serial structure has not yet been initialized - the
 134          MinGW select wrapper will not know that this FD refers
 135          to a socket.  */
 136       n = select (scb->fd + 1, &rset, &wset, &eset, &t);
 137     }
 138   else
 139     /* Use gdb_select here, since we have no file descriptors, and on
 140        Windows, plain select doesn't work in that case.  */
 141     n = gdb_select (0, NULL, NULL, NULL, &t);
 142
 143   /* If we didn't time out, only count it as one poll.  */
 144   if (n > 0 || *polls < POLL_INTERVAL)
 145     (*polls)++;
 146   else
 147     (*polls) += POLL_INTERVAL;
 148
 149   return n;
 150 }
 151
 152 /* Open a tcp socket.  */
 153
 154 int
 155 net_open (struct serial *scb, const char *name)
 156 {
 157   char *port_str, hostname[100];
 158   int n, port, tmp;
 159   int use_udp;
 160   struct hostent *hostent;
 161   struct sockaddr_in sockaddr;
 162 #ifdef USE_WIN32API
 163   u_long ioarg;
 164 #else
 165   int ioarg;
 166 #endif
 167   int polls = 0;
 168
 169   use_udp = 0;
 170   if (strncmp (name, "udp:", 4) == 0)
 171     {
 172       use_udp = 1;
 173       name = name + 4;
 174     }
 175   else if (strncmp (name, "tcp:", 4) == 0)
 176     name = name + 4;
 177
 178   port_str = strchr (name, ':');
 179
 180   if (!port_str)
 181     error (_("net_open: No colon in host name!"));  /* Shouldn't ever
 182                                                        happen.  */
 183
 184   tmp = min (port_str - name, (int) sizeof hostname - 1);
 185   strncpy (hostname, name, tmp);        /* Don't want colon.  */
 186   hostname[tmp] = '\000';       /* Tie off host name.  */
 187   port = atoi (port_str + 1);
 188
 189   /* Default hostname is localhost.  */
 190   if (!hostname[0])
 191     strcpy (hostname, "localhost");
 192
 193   hostent = gethostbyname (hostname);
 194   if (!hostent)
 195     {
 196       fprintf_unfiltered (gdb_stderr, "%s: unknown host\n", hostname);
 197       errno = ENOENT;
 198       return -1;
 199     }
 200
 201   sockaddr.sin_family = PF_INET;
 202   sockaddr.sin_port = htons (port);
 203   memcpy (&sockaddr.sin_addr.s_addr, hostent->h_addr,
 204           sizeof (struct in_addr));
 205
 206  retry:
 207
 208   if (use_udp)
 209     scb->fd = socket (PF_INET, SOCK_DGRAM, 0);
 210   else
 211     scb->fd = socket (PF_INET, SOCK_STREAM, 0);
 212
 213   if (scb->fd == -1)
 214     return -1;
 215
 216   /* Set socket nonblocking.  */
 217   ioarg = 1;
 218   ioctl (scb->fd, FIONBIO, &ioarg);
 219
 220   /* Use Non-blocking connect.  connect() will return 0 if connected
 221      already.  */
 222   n = connect (scb->fd, (struct sockaddr *) &sockaddr, sizeof (sockaddr));
 223
 224   if (n < 0)
 225     {
 226 #ifdef USE_WIN32API
 227       int err = WSAGetLastError();
 228 #else
 229       int err = errno;
 230 #endif
 231
 232       /* Maybe we're waiting for the remote target to become ready to
 233          accept connections.  */
 234       if (tcp_auto_retry
 235 #ifdef USE_WIN32API
 236           && err == WSAECONNREFUSED
 237 #else
 238           && err == ECONNREFUSED
 239 #endif
 240           && wait_for_connect (NULL, &polls) >= 0)
 241         {
 242           close (scb->fd);
 243           goto retry;
 244         }
 245
 246       if (
 247 #ifdef USE_WIN32API
 248           /* Under Windows, calling "connect" with a non-blocking socket
 249              results in WSAEWOULDBLOCK, not WSAEINPROGRESS.  */
 250           err != WSAEWOULDBLOCK
 251 #else
 252           err != EINPROGRESS
 253 #endif
 254           )
 255         {
 256           errno = err;
 257           net_close (scb);
 258           return -1;
 259         }
 260
 261       /* Looks like we need to wait for the connect.  */
 262       do
 263         {
 264           n = wait_for_connect (scb, &polls);
 265         }
 266       while (n == 0);
 267       if (n < 0)
 268         {
 269           net_close (scb);
 270           return -1;
 271         }
 272     }
 273
 274   /* Got something.  Is it an error?  */
 275   {
 276     int res, err;
 277     socklen_t len;
 278
 279     len = sizeof (err);
 280     /* On Windows, the fourth parameter to getsockopt is a "char *";
 281        on UNIX systems it is generally "void *".  The cast to "void *"
 282        is OK everywhere, since in C "void *" can be implicitly
 283        converted to any pointer type.  */
 284     res = getsockopt (scb->fd, SOL_SOCKET, SO_ERROR, (void *) &err, &len);
 285     if (res < 0 || err)
 286       {
 287         /* Maybe the target still isn't ready to accept the connection.  */
 288         if (tcp_auto_retry
 289 #ifdef USE_WIN32API
 290             && err == WSAECONNREFUSED
 291 #else
 292             && err == ECONNREFUSED
 293 #endif
 294             && wait_for_connect (NULL, &polls) >= 0)
 295           {
 296             close (scb->fd);
 297             goto retry;
 298           }
 299         if (err)
 300           errno = err;
 301         net_close (scb);
 302         return -1;
 303       }
 304   }
 305
 306   /* Turn off nonblocking.  */
 307   ioarg = 0;
 308   ioctl (scb->fd, FIONBIO, &ioarg);
 309
 310   if (use_udp == 0)
 311     {
 312       /* Disable Nagle algorithm.  Needed in some cases.  */
 313       tmp = 1;
 314       setsockopt (scb->fd, IPPROTO_TCP, TCP_NODELAY,
 315                   (char *)&tmp, sizeof (tmp));
 316     }
 317
 318 #ifdef SIGPIPE
 319   /* If we don't do this, then GDB simply exits
 320      when the remote side dies.  */
 321   signal (SIGPIPE, SIG_IGN);
 322 #endif
 323
 324   return 0;
 325 }
 326
 327 void
 328 net_close (struct serial *scb)
 329 {
 330   if (scb->fd == -1)
 331     return;
 332
 333   close (scb->fd);
 334   scb->fd = -1;
 335 }
 336
 337 int
 338 net_read_prim (struct serial *scb, size_t count)
 339 {
 340   return recv (scb->fd, scb->buf, count, 0);
 341 }
 342
 343 int
 344 net_write_prim (struct serial *scb, const void *buf, size_t count)
 345 {
 346   return send (scb->fd, buf, count, 0);
 347 }
 348
 349 int
 350 ser_tcp_send_break (struct serial *scb)
 351 {
 352   /* Send telnet IAC and BREAK characters.  */
 353   return (serial_write (scb, "\377\363", 2));
 354 }
 355
 356 /* Support for "set tcp" and "show tcp" commands.  */
 357
 358 static void
 359 set_tcp_cmd (char *args, int from_tty)
 360 {
 361   help_list (tcp_set_cmdlist, "set tcp ", -1, gdb_stdout);
 362 }
 363
 364 static void
 365 show_tcp_cmd (char *args, int from_tty)
 366 {
 367   help_list (tcp_show_cmdlist, "show tcp ", -1, gdb_stdout);
 368 }
 369
 370
 371 void
 372 _initialize_ser_tcp (void)
 373 {
 374 #ifdef USE_WIN32API
 375   /* Do nothing; the TCP serial operations will be initialized in
 376      ser-mingw.c.  */
 377 #else
 378   struct serial_ops *ops;
 379
 380   ops = XMALLOC (struct serial_ops);
 381   memset (ops, 0, sizeof (struct serial_ops));
 382   ops->name = "tcp";
 383   ops->next = 0;
 384   ops->open = net_open;
 385   ops->close = net_close;
 386   ops->readchar = ser_base_readchar;
 387   ops->write = ser_base_write;
 388   ops->flush_output = ser_base_flush_output;
 389   ops->flush_input = ser_base_flush_input;
 390   ops->send_break = ser_tcp_send_break;
 391   ops->go_raw = ser_base_raw;
 392   ops->get_tty_state = ser_base_get_tty_state;
 393   ops->set_tty_state = ser_base_set_tty_state;
 394   ops->print_tty_state = ser_base_print_tty_state;
 395   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 396   ops->setbaudrate = ser_base_setbaudrate;
 397   ops->setstopbits = ser_base_setstopbits;
 398   ops->drain_output = ser_base_drain_output;
 399   ops->async = ser_base_async;
 400   ops->read_prim = net_read_prim;
 401   ops->write_prim = net_write_prim;
 402   serial_add_interface (ops);
 403 #endif /* USE_WIN32API */
 404
 405   add_prefix_cmd ("tcp", class_maintenance, set_tcp_cmd, _("\
 406 TCP protocol specific variables\n\
 407 Configure variables specific to remote TCP connections"),
 408                   &tcp_set_cmdlist, "set tcp ",
 409                   0 /* allow-unknown */, &setlist);
 410   add_prefix_cmd ("tcp", class_maintenance, show_tcp_cmd, _("\
 411 TCP protocol specific variables\n\
 412 Configure variables specific to remote TCP connections"),
 413                   &tcp_show_cmdlist, "show tcp ",
 414                   0 /* allow-unknown */, &showlist);
 415
 416   add_setshow_boolean_cmd ("auto-retry", class_obscure,
 417                            &tcp_auto_retry, _("\
 418 Set auto-retry on socket connect"), _("\
 419 Show auto-retry on socket connect"),
 420                            NULL, NULL, NULL,
 421                            &tcp_set_cmdlist, &tcp_show_cmdlist);
 422
 423   add_setshow_uinteger_cmd ("connect-timeout", class_obscure,
 424                             &tcp_retry_limit, _("\
 425 Set timeout limit for socket connection"), _("\
 426 Show timeout limit for socket connection"),
 427                            NULL, NULL, NULL,
 428                            &tcp_set_cmdlist, &tcp_show_cmdlist);
 429 }