src/server/tcl_server.c

   1 /***************************************************************************
   2  *   Copyright (C) 2010 Øyvind Harboe                                      *
   3  *   oyvind.harboe@zylin.com                                               *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  19  ***************************************************************************/
  20
  21 #ifdef HAVE_CONFIG_H
  22 #include "config.h"
  23 #endif
  24
  25 #include "tcl_server.h"
  26
  27
  28 #define TCL_SERVER_VERSION      "TCL Server 0.1"
  29 #define TCL_MAX_LINE            (4096)
  30
  31 struct tcl_connection {
  32         int tc_linedrop;
  33         int tc_lineoffset;
  34         char tc_line[TCL_MAX_LINE];
  35         int tc_outerror; /* flag an output error */
  36 };
  37
  38 static unsigned short tcl_port = 6666;
  39
  40 /* handlers */
  41 static int tcl_new_connection(struct connection *connection);
  42 static int tcl_input(struct connection *connection);
  43 static int tcl_output(struct connection *connection, const void *buf, ssize_t len);
  44 static int tcl_closed(struct connection *connection);
  45
  46 /* write data out to a socket.
  47  *
  48  * this is a blocking write, so the return value must equal the length, if
  49  * that is not the case then flag the connection with an output error.
  50  */
  51 int tcl_output(struct connection *connection, const void *data, ssize_t len)
  52 {
  53         ssize_t wlen;
  54         struct tcl_connection *tclc;
  55
  56         tclc = connection->priv;
  57         if (tclc->tc_outerror)
  58                 return ERROR_SERVER_REMOTE_CLOSED;
  59
  60         wlen = write_socket(connection->fd, data, len);
  61
  62         if (wlen == len)
  63                 return ERROR_OK;
  64
  65         LOG_ERROR("error during write: %d != %d", (int)wlen, (int)len);
  66         tclc->tc_outerror = 1;
  67         return ERROR_SERVER_REMOTE_CLOSED;
  68 }
  69
  70 /* connections */
  71 static int tcl_new_connection(struct connection *connection)
  72 {
  73         struct tcl_connection *tclc;
  74
  75         tclc = malloc(sizeof(struct tcl_connection));
  76         if (tclc == NULL)
  77                 return ERROR_CONNECTION_REJECTED;
  78
  79         memset(tclc, 0, sizeof(struct tcl_connection));
  80         connection->priv = tclc;
  81         return ERROR_OK;
  82 }
  83
  84 static int tcl_input(struct connection *connection)
  85 {
  86         Jim_Interp *interp = (Jim_Interp *)connection->cmd_ctx->interp;
  87         int retval;
  88         int i;
  89         ssize_t rlen;
  90         const char *result;
  91         int reslen;
  92         struct tcl_connection *tclc;
  93         unsigned char in[256];
  94
  95         rlen = read_socket(connection->fd, &in, sizeof(in));
  96         if (rlen <= 0) {
  97                 if (rlen < 0)
  98                         LOG_ERROR("error during read: %s", strerror(errno));
  99                 return ERROR_SERVER_REMOTE_CLOSED;
 100         }
 101
 102         tclc = connection->priv;
 103         if (tclc == NULL)
 104                 return ERROR_CONNECTION_REJECTED;
 105
 106         /* push as much data into the line as possible */
 107         for (i = 0; i < rlen; i++)
 108         {
 109                 /* buffer the data */
 110                 tclc->tc_line[tclc->tc_lineoffset] = in[i];
 111                 if (tclc->tc_lineoffset < TCL_MAX_LINE)
 112                         tclc->tc_lineoffset++;
 113                 else
 114                         tclc->tc_linedrop = 1;
 115
 116                 /* ctrl-z is end of command. When testing from telnet, just
 117                  * press ctrl-z a couple of times first to put telnet into the
 118                  * mode where it will send 0x1a in response to pressing ctrl-z
 119                  */
 120                 if (in[i] != '\x1a')
 121                         continue;
 122
 123                 /* process the line */
 124                 if (tclc->tc_linedrop) {
 125 #define ESTR "line too long\n"
 126                         retval = tcl_output(connection, ESTR, sizeof(ESTR));
 127                         if (retval != ERROR_OK)
 128                                 return retval;
 129 #undef ESTR
 130                 }
 131                 else {
 132                         tclc->tc_line[tclc->tc_lineoffset-1] = '\0';
 133                         LOG_DEBUG("Executing script:\n %s", tclc->tc_line);
 134                         retval = Jim_Eval_Named(interp, tclc->tc_line, "remote:connection",1);
 135                         LOG_DEBUG("Result: %d\n %s", retval, Jim_GetString(Jim_GetResult(interp), &reslen));
 136                         result = Jim_GetString(Jim_GetResult(interp), &reslen);
 137                         retval = tcl_output(connection, result, reslen);
 138                         if (retval != ERROR_OK)
 139                                 return retval;
 140                         /* Always output ctrl-d as end of line to allow multiline results */
 141                         tcl_output(connection, "\x1a", 1);
 142                 }
 143
 144                 tclc->tc_lineoffset = 0;
 145                 tclc->tc_linedrop = 0;
 146         }
 147
 148         return ERROR_OK;
 149 }
 150
 151 static int tcl_closed(struct connection *connection)
 152 {
 153         /* cleanup connection context */
 154         if (connection->priv) {
 155                 free(connection->priv);
 156                 connection->priv = NULL;
 157         }
 158         return ERROR_OK;
 159 }
 160
 161 int tcl_init(void)
 162 {
 163         int retval;
 164
 165         if (tcl_port == 0)
 166         {
 167                 LOG_INFO("tcl port disabled");
 168                 return ERROR_OK;
 169         }
 170
 171         retval = add_service("tcl", CONNECTION_TCP, tcl_port, 1,
 172                         &tcl_new_connection, &tcl_input,
 173                         &tcl_closed, NULL);
 174         return retval;
 175 }
 176
 177 COMMAND_HANDLER(handle_tcl_port_command)
 178 {
 179         return CALL_COMMAND_HANDLER(server_port_command, &tcl_port);
 180 }
 181
 182 static const struct command_registration tcl_command_handlers[] = {
 183         {
 184                 .name = "tcl_port",
 185                 .handler = handle_tcl_port_command,
 186                 .mode = COMMAND_CONFIG,
 187                 .help = "Specify port on which to listen "
 188                         "for incoming Tcl syntax.  "
 189                         "No arguments reports Tcl port; zero disables.",
 190                 .usage = "[port_num]",
 191         },
 192         COMMAND_REGISTRATION_DONE
 193 };
 194
 195 int tcl_register_commands(struct command_context *cmd_ctx)
 196 {
 197         return register_commands(cmd_ctx, NULL, tcl_command_handlers);
 198 }