gdb/ser-tcp.c - gdb

Global variables defined

Data types defined

Functions defined

Macros defined

Source code

  1. /* Serial interface for raw TCP connections on Un*x like systems.

  3.    Copyright (C) 1992-2015 Free Software Foundation, Inc.

  5.    This file is part of GDB.

  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.

  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.

  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/>.  */

  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"

  29. #include <sys/types.h>

  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

  38. #include <sys/time.h>

  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

  55. #include <signal.h>
  56. #include "gdb_select.h"

  58. #ifndef HAVE_SOCKLEN_T
  59. ‌typedef int socklen_t;
  60. #endif

  62. void _initialize_ser_tcp (void);

  64. /* For "set tcp" and "show tcp".  */

  66. ‌static struct cmd_list_element *tcp_set_cmdlist;
  67. ‌static struct cmd_list_element *tcp_show_cmdlist;

  69. /* Whether to auto-retry refused connections.  */

  71. ‌static int tcp_auto_retry = 1;

  73. /* Timeout period for connections, in seconds.  */

  75. ‌static unsigned int tcp_retry_limit = 15;

  77. /* How many times per second to poll deprecated_ui_loop_hook.  */

  79. ‌#define POLL_INTERVAL 5

  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.  */

  85. static int
  86. ‌wait_for_connect (struct serial *scb, unsigned int *polls)
  87. {
  88.   struct timeval t;
  89.   int n;

  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.     }

  100.   /* Check for timeout.  */
  101.   if (*polls > tcp_retry_limit * POLL_INTERVAL)
  102.     {
  103.       errno = ETIMEDOUT;
  104.       return -1;
  105.     }

  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.     }

  120.   if (scb)
  121.     {
  122.       fd_set rset, wset, eset;

  124.       FD_ZERO (&rset);
  125.       FD_SET (scb->fd, &rset);
  126.       wset = rset;
  127.       eset = rset;

  129.       /* POSIX systems return connection success or failure by signalling
  130.          wset.  Windows systems return success in wset and failure in
  131.          eset.

  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);

  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;

  150.   return n;
  151. }

  153. /* Open a tcp socket.  */

  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;

  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;

  179.   port_str = strchr (name, ':');

  181.   if (!port_str)
  182.     error (_("net_open: No colon in host name!"));  /* Shouldn't ever
  183.                                                        happen.  */

  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);

  190.   /* Default hostname is localhost.  */
  191.   if (!hostname[0])
  192.     strcpy (hostname, "localhost");

  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.     }

  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));

  207. retry:

  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);

  214.   if (scb->fd == -1)
  215.     return -1;

  217.   /* Set socket nonblocking.  */
  218.   ioarg = 1;
  219.   ioctl (scb->fd, FIONBIO, &ioarg);

  221.   /* Use Non-blocking connect.  connect() will return 0 if connected
  222.      already.  */
  223.   n = connect (scb->fd, (struct sockaddr *) &sockaddr, sizeof (sockaddr));

  225.   if (n < 0)
  226.     {
  227. #ifdef USE_WIN32API
  228.       int err = WSAGetLastError();
  229. #else
  230.       int err = errno;
  231. #endif

  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.         }

  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.         }

  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.     }

  275.   /* Got something.  Is it an error?  */
  276.   {
  277.     int res, err;
  278.     socklen_t len;

  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.   }

  307.   /* Turn off nonblocking.  */
  308.   ioarg = 0;
  309.   ioctl (scb->fd, FIONBIO, &ioarg);

  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.     }

  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

  325.   return 0;
  326. }

  328. void
  329. ‌net_close (struct serial *scb)
  330. {
  331.   if (scb->fd == -1)
  332.     return;

  334.   close (scb->fd);
  335.   scb->fd = -1;
  336. }

  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. }

  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. }

  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. }

  360. /* Support for "set tcp" and "show tcp" commands.  */

  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. }

  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. }

  374. #ifndef USE_WIN32API

  376. /* The TCP ops.  */

  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. };

  403. #endif /* USE_WIN32API */

  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 */

  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);

  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);

  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. }