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 <sys/time.h>
  39
  40 #include "gdb_socket.h"
  41
  42 #ifdef USE_WIN32API
  43 #include <winsock2.h>
  44 #ifndef ETIMEDOUT
  45 #define ETIMEDOUT WSAETIMEDOUT
  46 #endif
  47 #define close(fd) closesocket (fd)
  48 #define ioctl ioctlsocket
  49 #else
  50 #include <arpa/inet.h>
  51 #include <netdb.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 *port_str, hostname[100];
 159   int n, port, tmp;
 160   int use_udp;
 161   struct hostent *hostent;
 162   union gdb_sockaddr_u 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 (startswith (name, "udp:"))
 172     {
 173       use_udp = 1;
 174       name = name + 4;
 175     }
 176   else if (startswith (name, "tcp:"))
 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.sa_in.sin_family = PF_INET;
 203   sockaddr.sa_in.sin_port = htons (port);
 204   memcpy (&sockaddr.sa_in.sin_addr.s_addr, hostent->h_addr,
 205           sizeof (struct in_addr));
 206
 207  retry:
 208
 209   if (use_udp)
 210     scb->fd = gdb_socket_cloexec (PF_INET, SOCK_DGRAM, 0);
 211   else
 212     scb->fd = gdb_socket_cloexec (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, &sockaddr.sa, sizeof (sockaddr.sa_in));
 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   /* Need to cast to silence -Wpointer-sign on MinGW, as Winsock's
 342      'recv' takes 'char *' as second argument, while 'scb->buf' is
 343      'unsigned char *'.  */
 344   return recv (scb->fd, (void *) scb->buf, count, 0);
 345 }
 346
 347 int
 348 net_write_prim (struct serial *scb, const void *buf, size_t count)
 349 {
 350   return send (scb->fd, buf, count, 0);
 351 }
 352
 353 int
 354 ser_tcp_send_break (struct serial *scb)
 355 {
 356   /* Send telnet IAC and BREAK characters.  */
 357   return (serial_write (scb, "\377\363", 2));
 358 }
 359
 360 /* Support for "set tcp" and "show tcp" commands.  */
 361
 362 static void
 363 set_tcp_cmd (char *args, int from_tty)
 364 {
 365   help_list (tcp_set_cmdlist, "set tcp ", all_commands, gdb_stdout);
 366 }
 367
 368 static void
 369 show_tcp_cmd (char *args, int from_tty)
 370 {
 371   help_list (tcp_show_cmdlist, "show tcp ", all_commands, gdb_stdout);
 372 }
 373
 374 #ifndef USE_WIN32API
 375
 376 /* The TCP ops.  */
 377
 378 static const struct serial_ops tcp_ops =
 379 {
 380   "tcp",
 381   net_open,
 382   net_close,
 383   NULL,
 384   ser_base_readchar,
 385   ser_base_write,
 386   ser_base_flush_output,
 387   ser_base_flush_input,
 388   ser_tcp_send_break,
 389   ser_base_raw,
 390   ser_base_get_tty_state,
 391   ser_base_copy_tty_state,
 392   ser_base_set_tty_state,
 393   ser_base_print_tty_state,
 394   ser_base_noflush_set_tty_state,
 395   ser_base_setbaudrate,
 396   ser_base_setstopbits,
 397   ser_base_drain_output,
 398   ser_base_async,
 399   net_read_prim,
 400   net_write_prim
 401 };
 402
 403 #endif /* USE_WIN32API */
 404
 405 void
 406 _initialize_ser_tcp (void)
 407 {
 408 #ifdef USE_WIN32API
 409   /* Do nothing; the TCP serial operations will be initialized in
 410      ser-mingw.c.  */
 411 #else
 412   serial_add_interface (&tcp_ops);
 413 #endif /* USE_WIN32API */
 414
 415   add_prefix_cmd ("tcp", class_maintenance, set_tcp_cmd, _("\
 416 TCP protocol specific variables\n\
 417 Configure variables specific to remote TCP connections"),
 418                   &tcp_set_cmdlist, "set tcp ",
 419                   0 /* allow-unknown */, &setlist);
 420   add_prefix_cmd ("tcp", class_maintenance, show_tcp_cmd, _("\
 421 TCP protocol specific variables\n\
 422 Configure variables specific to remote TCP connections"),
 423                   &tcp_show_cmdlist, "show tcp ",
 424                   0 /* allow-unknown */, &showlist);
 425
 426   add_setshow_boolean_cmd ("auto-retry", class_obscure,
 427                            &tcp_auto_retry, _("\
 428 Set auto-retry on socket connect"), _("\
 429 Show auto-retry on socket connect"),
 430                            NULL, NULL, NULL,
 431                            &tcp_set_cmdlist, &tcp_show_cmdlist);
 432
 433   add_setshow_uinteger_cmd ("connect-timeout", class_obscure,
 434                             &tcp_retry_limit, _("\
 435 Set timeout limit in seconds for socket connection"), _("\
 436 Show timeout limit in seconds for socket connection"), _("\
 437 If set to \"unlimited\", GDB will keep attempting to establish a\n\
 438 connection forever, unless interrupted with Ctrl-c.\n\
 439 The default is 15 seconds."),
 440                             NULL, NULL,
 441                             &tcp_set_cmdlist, &tcp_show_cmdlist);
 442 }