gdb/ser-tcp.c

   1 /* Serial interface for raw TCP connections on Un*x like systems.
   2
   3    Copyright (C) 1992-2015 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 #include "filestuff.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 "gdb_sys_time.h"
  39
  40 #ifdef USE_WIN32API
  41 #include <winsock2.h>
  42 #ifndef ETIMEDOUT
  43 #define ETIMEDOUT WSAETIMEDOUT
  44 #endif
  45 #define close(fd) closesocket (fd)
  46 #define ioctl ioctlsocket
  47 #else
  48 #include <netinet/in.h>
  49 #include <arpa/inet.h>
  50 #include <netdb.h>
  51 #include <sys/socket.h>
  52 #include <netinet/tcp.h>
  53 #endif
  54
  55 #include <signal.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 hostname[100];
 159   const char *port_str;
 160   int n, port, tmp;
 161   int use_udp;
 162   struct hostent *hostent;
 163   struct sockaddr_in sockaddr;
 164 #ifdef USE_WIN32API
 165   u_long ioarg;
 166 #else
 167   int ioarg;
 168 #endif
 169   unsigned int polls = 0;
 170
 171   use_udp = 0;
 172   if (startswith (name, "udp:"))
 173     {
 174       use_udp = 1;
 175       name = name + 4;
 176     }
 177   else if (startswith (name, "tcp:"))
 178     name = name + 4;
 179
 180   port_str = strchr (name, ':');
 181
 182   if (!port_str)
 183     error (_("net_open: No colon in host name!"));  /* Shouldn't ever
 184                                                        happen.  */
 185
 186   tmp = min (port_str - name, (int) sizeof hostname - 1);
 187   strncpy (hostname, name, tmp);        /* Don't want colon.  */
 188   hostname[tmp] = '\000';       /* Tie off host name.  */
 189   port = atoi (port_str + 1);
 190
 191   /* Default hostname is localhost.  */
 192   if (!hostname[0])
 193     strcpy (hostname, "localhost");
 194
 195   hostent = gethostbyname (hostname);
 196   if (!hostent)
 197     {
 198       fprintf_unfiltered (gdb_stderr, "%s: unknown host\n", hostname);
 199       errno = ENOENT;
 200       return -1;
 201     }
 202
 203   sockaddr.sin_family = PF_INET;
 204   sockaddr.sin_port = htons (port);
 205   memcpy (&sockaddr.sin_addr.s_addr, hostent->h_addr,
 206           sizeof (struct in_addr));
 207
 208  retry:
 209
 210   if (use_udp)
 211     scb->fd = gdb_socket_cloexec (PF_INET, SOCK_DGRAM, 0);
 212   else
 213     scb->fd = gdb_socket_cloexec (PF_INET, SOCK_STREAM, 0);
 214
 215   if (scb->fd == -1)
 216     return -1;
 217
 218   /* Set socket nonblocking.  */
 219   ioarg = 1;
 220   ioctl (scb->fd, FIONBIO, &ioarg);
 221
 222   /* Use Non-blocking connect.  connect() will return 0 if connected
 223      already.  */
 224   n = connect (scb->fd, (struct sockaddr *) &sockaddr, sizeof (sockaddr));
 225
 226   if (n < 0)
 227     {
 228 #ifdef USE_WIN32API
 229       int err = WSAGetLastError();
 230 #else
 231       int err = errno;
 232 #endif
 233
 234       /* Maybe we're waiting for the remote target to become ready to
 235          accept connections.  */
 236       if (tcp_auto_retry
 237 #ifdef USE_WIN32API
 238           && err == WSAECONNREFUSED
 239 #else
 240           && err == ECONNREFUSED
 241 #endif
 242           && wait_for_connect (NULL, &polls) >= 0)
 243         {
 244           close (scb->fd);
 245           goto retry;
 246         }
 247
 248       if (
 249 #ifdef USE_WIN32API
 250           /* Under Windows, calling "connect" with a non-blocking socket
 251              results in WSAEWOULDBLOCK, not WSAEINPROGRESS.  */
 252           err != WSAEWOULDBLOCK
 253 #else
 254           err != EINPROGRESS
 255 #endif
 256           )
 257         {
 258           errno = err;
 259           net_close (scb);
 260           return -1;
 261         }
 262
 263       /* Looks like we need to wait for the connect.  */
 264       do
 265         {
 266           n = wait_for_connect (scb, &polls);
 267         }
 268       while (n == 0);
 269       if (n < 0)
 270         {
 271           net_close (scb);
 272           return -1;
 273         }
 274     }
 275
 276   /* Got something.  Is it an error?  */
 277   {
 278     int res, err;
 279     socklen_t len;
 280
 281     len = sizeof (err);
 282     /* On Windows, the fourth parameter to getsockopt is a "char *";
 283        on UNIX systems it is generally "void *".  The cast to "void *"
 284        is OK everywhere, since in C "void *" can be implicitly
 285        converted to any pointer type.  */
 286     res = getsockopt (scb->fd, SOL_SOCKET, SO_ERROR, (void *) &err, &len);
 287     if (res < 0 || err)
 288       {
 289         /* Maybe the target still isn't ready to accept the connection.  */
 290         if (tcp_auto_retry
 291 #ifdef USE_WIN32API
 292             && err == WSAECONNREFUSED
 293 #else
 294             && err == ECONNREFUSED
 295 #endif
 296             && wait_for_connect (NULL, &polls) >= 0)
 297           {
 298             close (scb->fd);
 299             goto retry;
 300           }
 301         if (err)
 302           errno = err;
 303         net_close (scb);
 304         return -1;
 305       }
 306   }
 307
 308   /* Turn off nonblocking.  */
 309   ioarg = 0;
 310   ioctl (scb->fd, FIONBIO, &ioarg);
 311
 312   if (use_udp == 0)
 313     {
 314       /* Disable Nagle algorithm.  Needed in some cases.  */
 315       tmp = 1;
 316       setsockopt (scb->fd, IPPROTO_TCP, TCP_NODELAY,
 317                   (char *)&tmp, sizeof (tmp));
 318     }
 319
 320 #ifdef SIGPIPE
 321   /* If we don't do this, then GDB simply exits
 322      when the remote side dies.  */
 323   signal (SIGPIPE, SIG_IGN);
 324 #endif
 325
 326   return 0;
 327 }
 328
 329 void
 330 net_close (struct serial *scb)
 331 {
 332   if (scb->fd == -1)
 333     return;
 334
 335   close (scb->fd);
 336   scb->fd = -1;
 337 }
 338
 339 int
 340 net_read_prim (struct serial *scb, size_t count)
 341 {
 342   /* Need to cast to silence -Wpointer-sign on MinGW, as Winsock's
 343      'recv' takes 'char *' as second argument, while 'scb->buf' is
 344      'unsigned char *'.  */
 345   return recv (scb->fd, (void *) scb->buf, count, 0);
 346 }
 347
 348 int
 349 net_write_prim (struct serial *scb, const void *buf, size_t count)
 350 {
 351   return send (scb->fd, buf, count, 0);
 352 }
 353
 354 int
 355 ser_tcp_send_break (struct serial *scb)
 356 {
 357   /* Send telnet IAC and BREAK characters.  */
 358   return (serial_write (scb, "\377\363", 2));
 359 }
 360
 361 /* Support for "set tcp" and "show tcp" commands.  */
 362
 363 static void
 364 set_tcp_cmd (char *args, int from_tty)
 365 {
 366   help_list (tcp_set_cmdlist, "set tcp ", all_commands, gdb_stdout);
 367 }
 368
 369 static void
 370 show_tcp_cmd (char *args, int from_tty)
 371 {
 372   help_list (tcp_show_cmdlist, "show tcp ", all_commands, gdb_stdout);
 373 }
 374
 375 #ifndef USE_WIN32API
 376
 377 /* The TCP ops.  */
 378
 379 static const struct serial_ops tcp_ops =
 380 {
 381   "tcp",
 382   net_open,
 383   net_close,
 384   NULL,
 385   ser_base_readchar,
 386   ser_base_write,
 387   ser_base_flush_output,
 388   ser_base_flush_input,
 389   ser_tcp_send_break,
 390   ser_base_raw,
 391   ser_base_get_tty_state,
 392   ser_base_copy_tty_state,
 393   ser_base_set_tty_state,
 394   ser_base_print_tty_state,
 395   ser_base_noflush_set_tty_state,
 396   ser_base_setbaudrate,
 397   ser_base_setstopbits,
 398   ser_base_setparity,
 399   ser_base_drain_output,
 400   ser_base_async,
 401   net_read_prim,
 402   net_write_prim
 403 };
 404
 405 #endif /* USE_WIN32API */
 406
 407 void
 408 _initialize_ser_tcp (void)
 409 {
 410 #ifdef USE_WIN32API
 411   /* Do nothing; the TCP serial operations will be initialized in
 412      ser-mingw.c.  */
 413 #else
 414   serial_add_interface (&tcp_ops);
 415 #endif /* USE_WIN32API */
 416
 417   add_prefix_cmd ("tcp", class_maintenance, set_tcp_cmd, _("\
 418 TCP protocol specific variables\n\
 419 Configure variables specific to remote TCP connections"),
 420                   &tcp_set_cmdlist, "set tcp ",
 421                   0 /* allow-unknown */, &setlist);
 422   add_prefix_cmd ("tcp", class_maintenance, show_tcp_cmd, _("\
 423 TCP protocol specific variables\n\
 424 Configure variables specific to remote TCP connections"),
 425                   &tcp_show_cmdlist, "show tcp ",
 426                   0 /* allow-unknown */, &showlist);
 427
 428   add_setshow_boolean_cmd ("auto-retry", class_obscure,
 429                            &tcp_auto_retry, _("\
 430 Set auto-retry on socket connect"), _("\
 431 Show auto-retry on socket connect"),
 432                            NULL, NULL, NULL,
 433                            &tcp_set_cmdlist, &tcp_show_cmdlist);
 434
 435   add_setshow_uinteger_cmd ("connect-timeout", class_obscure,
 436                             &tcp_retry_limit, _("\
 437 Set timeout limit in seconds for socket connection"), _("\
 438 Show timeout limit in seconds for socket connection"), _("\
 439 If set to \"unlimited\", GDB will keep attempting to establish a\n\
 440 connection forever, unless interrupted with Ctrl-c.\n\
 441 The default is 15 seconds."),
 442                             NULL, NULL,
 443                             &tcp_set_cmdlist, &tcp_show_cmdlist);
 444 }