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         if (wlen == len)
  62                 return ERROR_OK;
  63
  64         LOG_ERROR("error during write: %d != %d", (int)wlen, (int)len);
  65         tclc->tc_outerror = 1;
  66         return ERROR_SERVER_REMOTE_CLOSED;
  67 }
  68
  69 /* connections */
  70 static int tcl_new_connection(struct connection *connection)
  71 {
  72         struct tcl_connection *tclc;
  73
  74         tclc = malloc(sizeof(struct tcl_connection));
  75         if (tclc == NULL)
  76                 return ERROR_CONNECTION_REJECTED;
  77
  78         memset(tclc, 0, sizeof(struct tcl_connection));
  79         connection->priv = tclc;
  80         return ERROR_OK;
  81 }
  82
  83 static int tcl_input(struct connection *connection)
  84 {
  85         Jim_Interp *interp = (Jim_Interp *)connection->cmd_ctx->interp;
  86         int retval;
  87         int i;
  88         ssize_t rlen;
  89         const char *result;
  90         int reslen;
  91         struct tcl_connection *tclc;
  92         unsigned char in[256];
  93
  94         rlen = read_socket(connection->fd, &in, sizeof(in));
  95         if (rlen <= 0) {
  96                 if (rlen < 0)
  97                         LOG_ERROR("error during read: %s", strerror(errno));
  98                 return ERROR_SERVER_REMOTE_CLOSED;
  99         }
 100
 101         tclc = connection->priv;
 102         if (tclc == NULL)
 103                 return ERROR_CONNECTION_REJECTED;
 104
 105         /* push as much data into the line as possible */
 106         for (i = 0; i < rlen; i++)
 107         {
 108                 /* buffer the data */
 109                 tclc->tc_line[tclc->tc_lineoffset] = in[i];
 110                 if (tclc->tc_lineoffset < TCL_MAX_LINE)
 111                         tclc->tc_lineoffset++;
 112                 else
 113                         tclc->tc_linedrop = 1;
 114
 115                 /* ctrl-z is end of command. When testing from telnet, just
 116                  * press ctrl-z a couple of times first to put telnet into the
 117                  * mode where it will send 0x1a in response to pressing ctrl-z
 118                  */
 119                 if (in[i] != '\x1a')
 120                         continue;
 121
 122                 /* process the line */
 123                 if (tclc->tc_linedrop) {
 124 #define ESTR "line too long\n"
 125                         retval = tcl_output(connection, ESTR, sizeof(ESTR));
 126                         if (retval != ERROR_OK)
 127                                 return retval;
 128 #undef ESTR
 129                 }
 130                 else {
 131                         tclc->tc_line[tclc->tc_lineoffset-1] = '\0';
 132                         LOG_DEBUG("Executing script:\n %s", tclc->tc_line);
 133                         retval = Jim_Eval_Named(interp, tclc->tc_line, "remote:connection",1);
 134                         LOG_DEBUG("Result: %d\n %s", retval, Jim_GetString(Jim_GetResult(interp), &reslen));
 135                         result = Jim_GetString(Jim_GetResult(interp), &reslen);
 136                         retval = tcl_output(connection, result, reslen);
 137                         if (retval != ERROR_OK)
 138                                 return retval;
 139                         /* Always output ctrl-d as end of line to allow multiline results */
 140                         tcl_output(connection, "\x1a", 1);
 141                 }
 142
 143                 tclc->tc_lineoffset = 0;
 144                 tclc->tc_linedrop = 0;
 145         }
 146
 147         return ERROR_OK;
 148 }
 149
 150 static int tcl_closed(struct connection *connection)
 151 {
 152         /* cleanup connection context */
 153         if (connection->priv) {
 154                 free(connection->priv);
 155                 connection->priv = NULL;
 156         }
 157         return ERROR_OK;
 158 }
 159
 160 int tcl_init(void)
 161 {
 162         int retval;
 163
 164         if (tcl_port == 0)
 165         {
 166                 LOG_INFO("tcl port disabled");
 167                 return ERROR_OK;
 168         }
 169
 170         retval = add_service("tcl", CONNECTION_TCP, tcl_port, 1,
 171                         &tcl_new_connection, &tcl_input,
 172                         &tcl_closed, NULL);
 173         return retval;
 174 }
 175
 176 COMMAND_HANDLER(handle_tcl_port_command)
 177 {
 178         return CALL_COMMAND_HANDLER(server_port_command, &tcl_port);
 179 }
 180
 181 static const struct command_registration tcl_command_handlers[] = {
 182         {
 183                 .name = "tcl_port",
 184                 .handler = handle_tcl_port_command,
 185                 .mode = COMMAND_CONFIG,
 186                 .help = "Specify port on which to listen "
 187                         "for incoming Tcl syntax.  "
 188                         "No arguments reports Tcl port; zero disables.",
 189                 .usage = "[port_num]",
 190         },
 191         COMMAND_REGISTRATION_DONE
 192 };
 193
 194 int tcl_register_commands(struct command_context *cmd_ctx)
 195 {
 196         return register_commands(cmd_ctx, NULL, tcl_command_handlers);
 197 }