Sat Mar 24 23:26:00 2007

Asterisk developer's documentation


app_zapras.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2005, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  *
00021  * \brief Execute an ISDN RAS
00022  * 
00023  * \ingroup applications
00024  */
00025 
00026 #include <sys/ioctl.h>
00027 #include <sys/wait.h>
00028 #ifdef __linux__
00029 #include <sys/signal.h>
00030 #else
00031 #include <signal.h>
00032 #endif /* __linux__ */
00033 
00034 #include <stdlib.h>
00035 #include <unistd.h>
00036 #include <string.h>
00037 #include <stdlib.h>
00038 #include <errno.h>
00039 #include <stdio.h>
00040 #include <fcntl.h>
00041 
00042 /* Need some zaptel help here */
00043 #ifdef __linux__
00044 #include <linux/zaptel.h>
00045 #else
00046 #include <zaptel.h>
00047 #endif /* __linux__ */
00048 
00049 #include "asterisk.h"
00050 
00051 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 7221 $")
00052 
00053 #include "asterisk/lock.h"
00054 #include "asterisk/file.h"
00055 #include "asterisk/logger.h"
00056 #include "asterisk/channel.h"
00057 #include "asterisk/pbx.h"
00058 #include "asterisk/module.h"
00059 #include "asterisk/options.h"
00060 
00061 static char *tdesc = "Zap RAS Application";
00062 
00063 static char *app = "ZapRAS";
00064 
00065 static char *synopsis = "Executes Zaptel ISDN RAS application";
00066 
00067 static char *descrip =
00068 "  ZapRAS(args): Executes a RAS server using pppd on the given channel.\n"
00069 "The channel must be a clear channel (i.e. PRI source) and a Zaptel\n"
00070 "channel to be able to use this function (No modem emulation is included).\n"
00071 "Your pppd must be patched to be zaptel aware. Arguments should be\n"
00072 "separated by | characters.\n";
00073 
00074 STANDARD_LOCAL_USER;
00075 
00076 LOCAL_USER_DECL;
00077 
00078 #define PPP_MAX_ARGS 32
00079 #define PPP_EXEC  "/usr/sbin/pppd"
00080 
00081 static pid_t spawn_ras(struct ast_channel *chan, char *args)
00082 {
00083    pid_t pid;
00084    int x;   
00085    char *c;
00086 
00087    char *argv[PPP_MAX_ARGS];
00088    int argc = 0;
00089    char *stringp=NULL;
00090 
00091    /* Start by forking */
00092    pid = fork();
00093    if (pid)
00094       return pid;
00095 
00096    /* Execute RAS on File handles */
00097    dup2(chan->fds[0], STDIN_FILENO);
00098 
00099    /* Close other file descriptors */
00100    for (x=STDERR_FILENO + 1;x<1024;x++) 
00101       close(x);
00102 
00103    /* Restore original signal handlers */
00104    for (x=0;x<NSIG;x++)
00105       signal(x, SIG_DFL);
00106 
00107    /* Reset all arguments */
00108    memset(argv, 0, sizeof(argv));
00109 
00110    /* First argument is executable, followed by standard
00111       arguments for zaptel PPP */
00112    argv[argc++] = PPP_EXEC;
00113    argv[argc++] = "nodetach";
00114 
00115    /* And all the other arguments */
00116    stringp=args;
00117    c = strsep(&stringp, "|");
00118    while(c && strlen(c) && (argc < (PPP_MAX_ARGS - 4))) {
00119       argv[argc++] = c;
00120       c = strsep(&stringp, "|");
00121    }
00122 
00123    argv[argc++] = "plugin";
00124    argv[argc++] = "zaptel.so";
00125    argv[argc++] = "stdin";
00126 
00127 #if 0
00128    for (x=0;x<argc;x++) {
00129       fprintf(stderr, "Arg %d: %s\n", x, argv[x]);
00130    }
00131 #endif
00132 
00133    /* Finally launch PPP */
00134    execv(PPP_EXEC, argv);
00135    fprintf(stderr, "Failed to exec PPPD!\n");
00136    exit(1);
00137 }
00138 
00139 static void run_ras(struct ast_channel *chan, char *args)
00140 {
00141    pid_t pid;
00142    int status;
00143    int res;
00144    int signalled = 0;
00145    struct zt_bufferinfo savebi;
00146    int x;
00147    
00148    res = ioctl(chan->fds[0], ZT_GET_BUFINFO, &savebi);
00149    if(res) {
00150       ast_log(LOG_WARNING, "Unable to check buffer policy on channel %s\n", chan->name);
00151       return;
00152    }
00153 
00154    pid = spawn_ras(chan, args);
00155    if (pid < 0) {
00156       ast_log(LOG_WARNING, "Failed to spawn RAS\n");
00157    } else {
00158       for (;;) {
00159          res = wait4(pid, &status, WNOHANG, NULL);
00160          if (!res) {
00161             /* Check for hangup */
00162             if (chan->_softhangup && !signalled) {
00163                ast_log(LOG_DEBUG, "Channel '%s' hungup.  Signalling RAS at %d to die...\n", chan->name, pid);
00164                kill(pid, SIGTERM);
00165                signalled=1;
00166             }
00167             /* Try again */
00168             sleep(1);
00169             continue;
00170          }
00171          if (res < 0) {
00172             ast_log(LOG_WARNING, "wait4 returned %d: %s\n", res, strerror(errno));
00173          }
00174          if (option_verbose > 2) {
00175             if (WIFEXITED(status)) {
00176                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated with status %d\n", chan->name, WEXITSTATUS(status));
00177             } else if (WIFSIGNALED(status)) {
00178                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated with signal %d\n", 
00179                    chan->name, WTERMSIG(status));
00180             } else {
00181                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated weirdly.\n", chan->name);
00182             }
00183          }
00184          /* Throw back into audio mode */
00185          x = 1;
00186          ioctl(chan->fds[0], ZT_AUDIOMODE, &x);
00187 
00188          /* Restore saved values */
00189          res = ioctl(chan->fds[0], ZT_SET_BUFINFO, &savebi);
00190          if (res < 0) {
00191             ast_log(LOG_WARNING, "Unable to set buffer policy on channel %s\n", chan->name);
00192          }
00193          break;
00194       }
00195    }
00196 }
00197 
00198 static int zapras_exec(struct ast_channel *chan, void *data)
00199 {
00200    int res=-1;
00201    char *args;
00202    struct localuser *u;
00203    ZT_PARAMS ztp;
00204 
00205    if (!data) 
00206       data = "";
00207 
00208    LOCAL_USER_ADD(u);
00209 
00210    args = ast_strdupa(data);
00211    if (!args) {
00212       ast_log(LOG_ERROR, "Out of memory\n");
00213       LOCAL_USER_REMOVE(u);
00214       return -1;
00215    }
00216    
00217    /* Answer the channel if it's not up */
00218    if (chan->_state != AST_STATE_UP)
00219       ast_answer(chan);
00220    if (strcasecmp(chan->type, "Zap")) {
00221       /* If it's not a zap channel, we're done.  Wait a couple of
00222          seconds and then hangup... */
00223       if (option_verbose > 1)
00224          ast_verbose(VERBOSE_PREFIX_2 "Channel %s is not a Zap channel\n", chan->name);
00225       sleep(2);
00226    } else {
00227       memset(&ztp, 0, sizeof(ztp));
00228       if (ioctl(chan->fds[0], ZT_GET_PARAMS, &ztp)) {
00229          ast_log(LOG_WARNING, "Unable to get zaptel parameters\n");
00230       } else if (ztp.sigtype != ZT_SIG_CLEAR) {
00231          if (option_verbose > 1)
00232             ast_verbose(VERBOSE_PREFIX_2 "Channel %s is not a clear channel\n", chan->name);
00233       } else {
00234          /* Everything should be okay.  Run PPP. */
00235          if (option_verbose > 2)
00236             ast_verbose(VERBOSE_PREFIX_3 "Starting RAS on %s\n", chan->name);
00237          /* Execute RAS */
00238          run_ras(chan, args);
00239       }
00240    }
00241    LOCAL_USER_REMOVE(u);
00242    return res;
00243 }
00244 
00245 int unload_module(void)
00246 {
00247    int res;
00248 
00249    res = ast_unregister_application(app);
00250    
00251    STANDARD_HANGUP_LOCALUSERS;
00252 
00253    return res;
00254 }
00255 
00256 int load_module(void)
00257 {
00258    return ast_register_application(app, zapras_exec, synopsis, descrip);
00259 }
00260 
00261 char *description(void)
00262 {
00263    return tdesc;
00264 }
00265 
00266 int usecount(void)
00267 {
00268    int res;
00269    STANDARD_USECOUNT(res);
00270    return res;
00271 }
00272 
00273 char *key()
00274 {
00275    return ASTERISK_GPL_KEY;
00276 }

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