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 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 happen */
 182
 183   tmp = min (port_str - name, (int) sizeof hostname - 1);
 184   strncpy (hostname, name, tmp);        /* Don't want colon */
 185   hostname[tmp] = '\000';       /* Tie off host name */
 186   port = atoi (port_str + 1);
 187
 188   /* default hostname is localhost */
 189   if (!hostname[0])
 190     strcpy (hostname, "localhost");
 191
 192   hostent = gethostbyname (hostname);
 193   if (!hostent)
 194     {
 195       fprintf_unfiltered (gdb_stderr, "%s: unknown host\n", hostname);
 196       errno = ENOENT;
 197       return -1;
 198     }
 199
 200   sockaddr.sin_family = PF_INET;
 201   sockaddr.sin_port = htons (port);
 202   memcpy (&sockaddr.sin_addr.s_addr, hostent->h_addr,
 203           sizeof (struct in_addr));
 204
 205  retry:
 206
 207   if (use_udp)
 208     scb->fd = socket (PF_INET, SOCK_DGRAM, 0);
 209   else
 210     scb->fd = socket (PF_INET, SOCK_STREAM, 0);
 211
 212   if (scb->fd == -1)
 213     return -1;
 214
 215   /* set socket nonblocking */
 216   ioarg = 1;
 217   ioctl (scb->fd, FIONBIO, &ioarg);
 218
 219   /* Use Non-blocking connect.  connect() will return 0 if connected already. */
 220   n = connect (scb->fd, (struct sockaddr *) &sockaddr, sizeof (sockaddr));
 221
 222   if (n < 0)
 223     {
 224 #ifdef USE_WIN32API
 225       int err = WSAGetLastError();
 226 #else
 227       int err = errno;
 228 #endif
 229
 230       /* Maybe we're waiting for the remote target to become ready to
 231          accept connections.  */
 232       if (tcp_auto_retry
 233 #ifdef USE_WIN32API
 234           && err == WSAECONNREFUSED
 235 #else
 236           && err == ECONNREFUSED
 237 #endif
 238           && wait_for_connect (NULL, &polls) >= 0)
 239         {
 240           close (scb->fd);
 241           goto retry;
 242         }
 243
 244       if (
 245 #ifdef USE_WIN32API
 246           /* Under Windows, calling "connect" with a non-blocking socket
 247              results in WSAEWOULDBLOCK, not WSAEINPROGRESS.  */
 248           err != WSAEWOULDBLOCK
 249 #else
 250           err != EINPROGRESS
 251 #endif
 252           )
 253         {
 254           errno = err;
 255           net_close (scb);
 256           return -1;
 257         }
 258
 259       /* looks like we need to wait for the connect */
 260       do
 261         {
 262           n = wait_for_connect (scb, &polls);
 263         }
 264       while (n == 0);
 265       if (n < 0)
 266         {
 267           net_close (scb);
 268           return -1;
 269         }
 270     }
 271
 272   /* Got something.  Is it an error? */
 273   {
 274     int res, err;
 275     socklen_t len;
 276
 277     len = sizeof (err);
 278     /* On Windows, the fourth parameter to getsockopt is a "char *";
 279        on UNIX systems it is generally "void *".  The cast to "void *"
 280        is OK everywhere, since in C "void *" can be implicitly
 281        converted to any pointer type.  */
 282     res = getsockopt (scb->fd, SOL_SOCKET, SO_ERROR, (void *) &err, &len);
 283     if (res < 0 || err)
 284       {
 285         /* Maybe the target still isn't ready to accept the connection.  */
 286         if (tcp_auto_retry
 287 #ifdef USE_WIN32API
 288             && err == WSAECONNREFUSED
 289 #else
 290             && err == ECONNREFUSED
 291 #endif
 292             && wait_for_connect (NULL, &polls) >= 0)
 293           {
 294             close (scb->fd);
 295             goto retry;
 296           }
 297         if (err)
 298           errno = err;
 299         net_close (scb);
 300         return -1;
 301       }
 302   }
 303
 304   /* turn off nonblocking */
 305   ioarg = 0;
 306   ioctl (scb->fd, FIONBIO, &ioarg);
 307
 308   if (use_udp == 0)
 309     {
 310       /* Disable Nagle algorithm. Needed in some cases. */
 311       tmp = 1;
 312       setsockopt (scb->fd, IPPROTO_TCP, TCP_NODELAY,
 313                   (char *)&tmp, sizeof (tmp));
 314     }
 315
 316 #ifdef SIGPIPE
 317   /* If we don't do this, then GDB simply exits
 318      when the remote side dies.  */
 319   signal (SIGPIPE, SIG_IGN);
 320 #endif
 321
 322   return 0;
 323 }
 324
 325 void
 326 net_close (struct serial *scb)
 327 {
 328   if (scb->fd == -1)
 329     return;
 330
 331   close (scb->fd);
 332   scb->fd = -1;
 333 }
 334
 335 int
 336 net_read_prim (struct serial *scb, size_t count)
 337 {
 338   return recv (scb->fd, scb->buf, count, 0);
 339 }
 340
 341 int
 342 net_write_prim (struct serial *scb, const void *buf, size_t count)
 343 {
 344   return send (scb->fd, buf, count, 0);
 345 }
 346
 347 int
 348 ser_tcp_send_break (struct serial *scb)
 349 {
 350   /* Send telnet IAC and BREAK characters. */
 351   return (serial_write (scb, "\377\363", 2));
 352 }
 353
 354 /* Support for "set tcp" and "show tcp" commands.  */
 355
 356 static void
 357 set_tcp_cmd (char *args, int from_tty)
 358 {
 359   help_list (tcp_set_cmdlist, "set tcp ", -1, gdb_stdout);
 360 }
 361
 362 static void
 363 show_tcp_cmd (char *args, int from_tty)
 364 {
 365   help_list (tcp_show_cmdlist, "show tcp ", -1, gdb_stdout);
 366 }
 367
 368
 369 void
 370 _initialize_ser_tcp (void)
 371 {
 372 #ifdef USE_WIN32API
 373   /* Do nothing; the TCP serial operations will be initialized in
 374      ser-mingw.c.  */
 375 #else
 376   struct serial_ops *ops;
 377
 378   ops = XMALLOC (struct serial_ops);
 379   memset (ops, 0, sizeof (struct serial_ops));
 380   ops->name = "tcp";
 381   ops->next = 0;
 382   ops->open = net_open;
 383   ops->close = net_close;
 384   ops->readchar = ser_base_readchar;
 385   ops->write = ser_base_write;
 386   ops->flush_output = ser_base_flush_output;
 387   ops->flush_input = ser_base_flush_input;
 388   ops->send_break = ser_tcp_send_break;
 389   ops->go_raw = ser_base_raw;
 390   ops->get_tty_state = ser_base_get_tty_state;
 391   ops->set_tty_state = ser_base_set_tty_state;
 392   ops->print_tty_state = ser_base_print_tty_state;
 393   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 394   ops->setbaudrate = ser_base_setbaudrate;
 395   ops->setstopbits = ser_base_setstopbits;
 396   ops->drain_output = ser_base_drain_output;
 397   ops->async = ser_base_async;
 398   ops->read_prim = net_read_prim;
 399   ops->write_prim = net_write_prim;
 400   serial_add_interface (ops);
 401 #endif /* USE_WIN32API */
 402
 403   add_prefix_cmd ("tcp", class_maintenance, set_tcp_cmd, _("\
 404 TCP protocol specific variables\n\
 405 Configure variables specific to remote TCP connections"),
 406                   &tcp_set_cmdlist, "set tcp ",
 407                   0 /* allow-unknown */, &setlist);
 408   add_prefix_cmd ("tcp", class_maintenance, show_tcp_cmd, _("\
 409 TCP protocol specific variables\n\
 410 Configure variables specific to remote TCP connections"),
 411                   &tcp_show_cmdlist, "show tcp ",
 412                   0 /* allow-unknown */, &showlist);
 413
 414   add_setshow_boolean_cmd ("auto-retry", class_obscure,
 415                            &tcp_auto_retry, _("\
 416 Set auto-retry on socket connect"), _("\
 417 Show auto-retry on socket connect"),
 418                            NULL, NULL, NULL,
 419                            &tcp_set_cmdlist, &tcp_show_cmdlist);
 420
 421   add_setshow_uinteger_cmd ("connect-timeout", class_obscure,
 422                             &tcp_retry_limit, _("\
 423 Set timeout limit for socket connection"), _("\
 424 Show timeout limit for socket connection"),
 425                            NULL, NULL, NULL,
 426                            &tcp_set_cmdlist, &tcp_show_cmdlist);
 427 }