gdb/ser-tcp.c

   1 /* Serial interface for raw TCP connections on Un*x like systems.
   2
   3    Copyright (C) 1992-2013 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   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.
  11
  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.
  16
  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/>.  */
  19
  20 #include "defs.h"
  21 #include "serial.h"
  22 #include "ser-base.h"
  23 #include "ser-tcp.h"
  24 #include "gdbcmd.h"
  25 #include "cli/cli-decode.h"
  26 #include "cli/cli-setshow.h"
  27
  28 #include <sys/types.h>
  29
  30 #ifdef HAVE_SYS_FILIO_H
  31 #include <sys/filio.h>  /* For FIONBIO.  */
  32 #endif
  33 #ifdef HAVE_SYS_IOCTL_H
  34 #include <sys/ioctl.h>  /* For FIONBIO.  */
  35 #endif
  36
  37 #include <sys/time.h>
  38
  39 #ifdef USE_WIN32API
  40 #include <winsock2.h>
  41 #ifndef ETIMEDOUT
  42 #define ETIMEDOUT WSAETIMEDOUT
  43 #endif
  44 #define close(fd) closesocket (fd)
  45 #define ioctl ioctlsocket
  46 #else
  47 #include <netinet/in.h>
  48 #include <arpa/inet.h>
  49 #include <netdb.h>
  50 #include <sys/socket.h>
  51 #include <netinet/tcp.h>
  52 #endif
  53
  54 #include <signal.h>
  55 #include "gdb_string.h"
  56 #include "gdb_select.h"
  57
  58 #ifndef HAVE_SOCKLEN_T
  59 typedef int socklen_t;
  60 #endif
  61
  62 void _initialize_ser_tcp (void);
  63
  64 /* For "set tcp" and "show tcp".  */
  65
  66 static struct cmd_list_element *tcp_set_cmdlist;
  67 static struct cmd_list_element *tcp_show_cmdlist;
  68
  69 /* Whether to auto-retry refused connections.  */
  70
  71 static int tcp_auto_retry = 1;
  72
  73 /* Timeout period for connections, in seconds.  */
  74
  75 static unsigned int tcp_retry_limit = 15;
  76
  77 /* How many times per second to poll deprecated_ui_loop_hook.  */
  78
  79 #define POLL_INTERVAL 5
  80
  81 /* Helper function to wait a while.  If SCB is non-null, wait on its
  82    file descriptor.  Otherwise just wait on a timeout, updating *POLLS.
  83    Returns -1 on timeout or interrupt, otherwise the value of select.  */
  84
  85 static int
  86 wait_for_connect (struct serial *scb, unsigned int *polls)
  87 {
  88   struct timeval t;
  89   int n;
  90
  91   /* While we wait for the connect to complete,
  92      poll the UI so it can update or the user can
  93      interrupt.  */
  94   if (deprecated_ui_loop_hook && deprecated_ui_loop_hook (0))
  95     {
  96       errno = EINTR;
  97       return -1;
  98     }
  99
 100   /* Check for timeout.  */
 101   if (*polls > tcp_retry_limit * POLL_INTERVAL)
 102     {
 103       errno = ETIMEDOUT;
 104       return -1;
 105     }
 106
 107   /* Back off to polling once per second after the first POLL_INTERVAL
 108      polls.  */
 109   if (*polls < POLL_INTERVAL)
 110     {
 111       t.tv_sec = 0;
 112       t.tv_usec = 1000000 / POLL_INTERVAL;
 113     }
 114   else
 115     {
 116       t.tv_sec = 1;
 117       t.tv_usec = 0;
 118     }
 119
 120   if (scb)
 121     {
 122       fd_set rset, wset, eset;
 123
 124       FD_ZERO (&rset);
 125       FD_SET (scb->fd, &rset);
 126       wset = rset;
 127       eset = rset;
 128
 129       /* POSIX systems return connection success or failure by signalling
 130          wset.  Windows systems return success in wset and failure in
 131          eset.
 132
 133          We must call select here, rather than gdb_select, because
 134          the serial structure has not yet been initialized - the
 135          MinGW select wrapper will not know that this FD refers
 136          to a socket.  */
 137       n = select (scb->fd + 1, &rset, &wset, &eset, &t);
 138     }
 139   else
 140     /* Use gdb_select here, since we have no file descriptors, and on
 141        Windows, plain select doesn't work in that case.  */
 142     n = gdb_select (0, NULL, NULL, NULL, &t);
 143
 144   /* If we didn't time out, only count it as one poll.  */
 145   if (n > 0 || *polls < POLL_INTERVAL)
 146     (*polls)++;
 147   else
 148     (*polls) += POLL_INTERVAL;
 149
 150   return n;
 151 }
 152
 153 /* Open a tcp socket.  */
 154
 155 int
 156 net_open (struct serial *scb, const char *name)
 157 {
 158   char *port_str, hostname[100];
 159   int n, port, tmp;
 160   int use_udp;
 161   struct hostent *hostent;
 162   struct sockaddr_in sockaddr;
 163 #ifdef USE_WIN32API
 164   u_long ioarg;
 165 #else
 166   int ioarg;
 167 #endif
 168   unsigned int polls = 0;
 169
 170   use_udp = 0;
 171   if (strncmp (name, "udp:", 4) == 0)
 172     {
 173       use_udp = 1;
 174       name = name + 4;
 175     }
 176   else if (strncmp (name, "tcp:", 4) == 0)
 177     name = name + 4;
 178
 179   port_str = strchr (name, ':');
 180
 181   if (!port_str)
 182     error (_("net_open: No colon in host name!"));  /* Shouldn't ever
 183                                                        happen.  */
 184
 185   tmp = min (port_str - name, (int) sizeof hostname - 1);
 186   strncpy (hostname, name, tmp);        /* Don't want colon.  */
 187   hostname[tmp] = '\000';       /* Tie off host name.  */
 188   port = atoi (port_str + 1);
 189
 190   /* Default hostname is localhost.  */
 191   if (!hostname[0])
 192     strcpy (hostname, "localhost");
 193
 194   hostent = gethostbyname (hostname);
 195   if (!hostent)
 196     {
 197       fprintf_unfiltered (gdb_stderr, "%s: unknown host\n", hostname);
 198       errno = ENOENT;
 199       return -1;
 200     }
 201
 202   sockaddr.sin_family = PF_INET;
 203   sockaddr.sin_port = htons (port);
 204   memcpy (&sockaddr.sin_addr.s_addr, hostent->h_addr,
 205           sizeof (struct in_addr));
 206
 207  retry:
 208
 209   if (use_udp)
 210     scb->fd = socket (PF_INET, SOCK_DGRAM, 0);
 211   else
 212     scb->fd = socket (PF_INET, SOCK_STREAM, 0);
 213
 214   if (scb->fd == -1)
 215     return -1;
 216
 217   /* Set socket nonblocking.  */
 218   ioarg = 1;
 219   ioctl (scb->fd, FIONBIO, &ioarg);
 220
 221   /* Use Non-blocking connect.  connect() will return 0 if connected
 222      already.  */
 223   n = connect (scb->fd, (struct sockaddr *) &sockaddr, sizeof (sockaddr));
 224
 225   if (n < 0)
 226     {
 227 #ifdef USE_WIN32API
 228       int err = WSAGetLastError();
 229 #else
 230       int err = errno;
 231 #endif
 232
 233       /* Maybe we're waiting for the remote target to become ready to
 234          accept connections.  */
 235       if (tcp_auto_retry
 236 #ifdef USE_WIN32API
 237           && err == WSAECONNREFUSED
 238 #else
 239           && err == ECONNREFUSED
 240 #endif
 241           && wait_for_connect (NULL, &polls) >= 0)
 242         {
 243           close (scb->fd);
 244           goto retry;
 245         }
 246
 247       if (
 248 #ifdef USE_WIN32API
 249           /* Under Windows, calling "connect" with a non-blocking socket
 250              results in WSAEWOULDBLOCK, not WSAEINPROGRESS.  */
 251           err != WSAEWOULDBLOCK
 252 #else
 253           err != EINPROGRESS
 254 #endif
 255           )
 256         {
 257           errno = err;
 258           net_close (scb);
 259           return -1;
 260         }
 261
 262       /* Looks like we need to wait for the connect.  */
 263       do
 264         {
 265           n = wait_for_connect (scb, &polls);
 266         }
 267       while (n == 0);
 268       if (n < 0)
 269         {
 270           net_close (scb);
 271           return -1;
 272         }
 273     }
 274
 275   /* Got something.  Is it an error?  */
 276   {
 277     int res, err;
 278     socklen_t len;
 279
 280     len = sizeof (err);
 281     /* On Windows, the fourth parameter to getsockopt is a "char *";
 282        on UNIX systems it is generally "void *".  The cast to "void *"
 283        is OK everywhere, since in C "void *" can be implicitly
 284        converted to any pointer type.  */
 285     res = getsockopt (scb->fd, SOL_SOCKET, SO_ERROR, (void *) &err, &len);
 286     if (res < 0 || err)
 287       {
 288         /* Maybe the target still isn't ready to accept the connection.  */
 289         if (tcp_auto_retry
 290 #ifdef USE_WIN32API
 291             && err == WSAECONNREFUSED
 292 #else
 293             && err == ECONNREFUSED
 294 #endif
 295             && wait_for_connect (NULL, &polls) >= 0)
 296           {
 297             close (scb->fd);
 298             goto retry;
 299           }
 300         if (err)
 301           errno = err;
 302         net_close (scb);
 303         return -1;
 304       }
 305   }
 306
 307   /* Turn off nonblocking.  */
 308   ioarg = 0;
 309   ioctl (scb->fd, FIONBIO, &ioarg);
 310
 311   if (use_udp == 0)
 312     {
 313       /* Disable Nagle algorithm.  Needed in some cases.  */
 314       tmp = 1;
 315       setsockopt (scb->fd, IPPROTO_TCP, TCP_NODELAY,
 316                   (char *)&tmp, sizeof (tmp));
 317     }
 318
 319 #ifdef SIGPIPE
 320   /* If we don't do this, then GDB simply exits
 321      when the remote side dies.  */
 322   signal (SIGPIPE, SIG_IGN);
 323 #endif
 324
 325   return 0;
 326 }
 327
 328 void
 329 net_close (struct serial *scb)
 330 {
 331   if (scb->fd == -1)
 332     return;
 333
 334   close (scb->fd);
 335   scb->fd = -1;
 336 }
 337
 338 int
 339 net_read_prim (struct serial *scb, size_t count)
 340 {
 341   return recv (scb->fd, scb->buf, count, 0);
 342 }
 343
 344 int
 345 net_write_prim (struct serial *scb, const void *buf, size_t count)
 346 {
 347   return send (scb->fd, buf, count, 0);
 348 }
 349
 350 int
 351 ser_tcp_send_break (struct serial *scb)
 352 {
 353   /* Send telnet IAC and BREAK characters.  */
 354   return (serial_write (scb, "\377\363", 2));
 355 }
 356
 357 /* Support for "set tcp" and "show tcp" commands.  */
 358
 359 static void
 360 set_tcp_cmd (char *args, int from_tty)
 361 {
 362   help_list (tcp_set_cmdlist, "set tcp ", -1, gdb_stdout);
 363 }
 364
 365 static void
 366 show_tcp_cmd (char *args, int from_tty)
 367 {
 368   help_list (tcp_show_cmdlist, "show tcp ", -1, gdb_stdout);
 369 }
 370
 371
 372 void
 373 _initialize_ser_tcp (void)
 374 {
 375 #ifdef USE_WIN32API
 376   /* Do nothing; the TCP serial operations will be initialized in
 377      ser-mingw.c.  */
 378 #else
 379   struct serial_ops *ops;
 380
 381   ops = XMALLOC (struct serial_ops);
 382   memset (ops, 0, sizeof (struct serial_ops));
 383   ops->name = "tcp";
 384   ops->next = 0;
 385   ops->open = net_open;
 386   ops->close = net_close;
 387   ops->readchar = ser_base_readchar;
 388   ops->write = ser_base_write;
 389   ops->flush_output = ser_base_flush_output;
 390   ops->flush_input = ser_base_flush_input;
 391   ops->send_break = ser_tcp_send_break;
 392   ops->go_raw = ser_base_raw;
 393   ops->get_tty_state = ser_base_get_tty_state;
 394   ops->copy_tty_state = ser_base_copy_tty_state;
 395   ops->set_tty_state = ser_base_set_tty_state;
 396   ops->print_tty_state = ser_base_print_tty_state;
 397   ops->noflush_set_tty_state = ser_base_noflush_set_tty_state;
 398   ops->setbaudrate = ser_base_setbaudrate;
 399   ops->setstopbits = ser_base_setstopbits;
 400   ops->drain_output = ser_base_drain_output;
 401   ops->async = ser_base_async;
 402   ops->read_prim = net_read_prim;
 403   ops->write_prim = net_write_prim;
 404   serial_add_interface (ops);
 405 #endif /* USE_WIN32API */
 406
 407   add_prefix_cmd ("tcp", class_maintenance, set_tcp_cmd, _("\
 408 TCP protocol specific variables\n\
 409 Configure variables specific to remote TCP connections"),
 410                   &tcp_set_cmdlist, "set tcp ",
 411                   0 /* allow-unknown */, &setlist);
 412   add_prefix_cmd ("tcp", class_maintenance, show_tcp_cmd, _("\
 413 TCP protocol specific variables\n\
 414 Configure variables specific to remote TCP connections"),
 415                   &tcp_show_cmdlist, "show tcp ",
 416                   0 /* allow-unknown */, &showlist);
 417
 418   add_setshow_boolean_cmd ("auto-retry", class_obscure,
 419                            &tcp_auto_retry, _("\
 420 Set auto-retry on socket connect"), _("\
 421 Show auto-retry on socket connect"),
 422                            NULL, NULL, NULL,
 423                            &tcp_set_cmdlist, &tcp_show_cmdlist);
 424
 425   add_setshow_uinteger_cmd ("connect-timeout", class_obscure,
 426                             &tcp_retry_limit, _("\
 427 Set timeout limit for socket connection"), _("\
 428 Show timeout limit for socket connection"),
 429                            NULL, NULL, NULL,
 430                            &tcp_set_cmdlist, &tcp_show_cmdlist);
 431 }