Mon Jul 14 17:24:50 2008

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  * \author Mark Spencer <markster@digium.com>
00024  * 
00025  * \ingroup applications
00026  */
00027 
00028 /*** MODULEINFO
00029    <depend>zaptel</depend>
00030  ***/
00031 
00032 #include "asterisk.h"
00033 
00034 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 48375 $")
00035 
00036 #include <sys/ioctl.h>
00037 #include <sys/wait.h>
00038 #ifdef __linux__
00039 #include <sys/signal.h>
00040 #else
00041 #include <signal.h>
00042 #endif /* __linux__ */
00043 
00044 #include <stdlib.h>
00045 #include <unistd.h>
00046 #include <string.h>
00047 #include <stdlib.h>
00048 #include <errno.h>
00049 #include <stdio.h>
00050 #include <fcntl.h>
00051 #include <zaptel/zaptel.h>
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 *app = "ZapRAS";
00062 
00063 static char *synopsis = "Executes Zaptel ISDN RAS application";
00064 
00065 static char *descrip =
00066 "  ZapRAS(args): Executes a RAS server using pppd on the given channel.\n"
00067 "The channel must be a clear channel (i.e. PRI source) and a Zaptel\n"
00068 "channel to be able to use this function (No modem emulation is included).\n"
00069 "Your pppd must be patched to be zaptel aware. Arguments should be\n"
00070 "separated by | characters.\n";
00071 
00072 
00073 #define PPP_MAX_ARGS 32
00074 #define PPP_EXEC  "/usr/sbin/pppd"
00075 
00076 static pid_t spawn_ras(struct ast_channel *chan, char *args)
00077 {
00078    pid_t pid;
00079    int x;   
00080    char *c;
00081 
00082    char *argv[PPP_MAX_ARGS];
00083    int argc = 0;
00084    char *stringp=NULL;
00085    sigset_t fullset, oldset;
00086 
00087    sigfillset(&fullset);
00088    pthread_sigmask(SIG_BLOCK, &fullset, &oldset);
00089 
00090    /* Start by forking */
00091    pid = fork();
00092    if (pid) {
00093       pthread_sigmask(SIG_SETMASK, &oldset, NULL);
00094       return pid;
00095    }
00096 
00097    /* Restore original signal handlers */
00098    for (x=0;x<NSIG;x++)
00099       signal(x, SIG_DFL);
00100 
00101    pthread_sigmask(SIG_UNBLOCK, &fullset, NULL);
00102 
00103    /* Execute RAS on File handles */
00104    dup2(chan->fds[0], STDIN_FILENO);
00105 
00106    /* Drop high priority */
00107    if (ast_opt_high_priority)
00108       ast_set_priority(0);
00109 
00110    /* Close other file descriptors */
00111    for (x=STDERR_FILENO + 1;x<1024;x++) 
00112       close(x);
00113 
00114    /* Reset all arguments */
00115    memset(argv, 0, sizeof(argv));
00116 
00117    /* First argument is executable, followed by standard
00118       arguments for zaptel PPP */
00119    argv[argc++] = PPP_EXEC;
00120    argv[argc++] = "nodetach";
00121 
00122    /* And all the other arguments */
00123    stringp=args;
00124    c = strsep(&stringp, "|");
00125    while(c && strlen(c) && (argc < (PPP_MAX_ARGS - 4))) {
00126       argv[argc++] = c;
00127       c = strsep(&stringp, "|");
00128    }
00129 
00130    argv[argc++] = "plugin";
00131    argv[argc++] = "zaptel.so";
00132    argv[argc++] = "stdin";
00133 
00134    /* Finally launch PPP */
00135    execv(PPP_EXEC, argv);
00136    fprintf(stderr, "Failed to exec PPPD!\n");
00137    exit(1);
00138 }
00139 
00140 static void run_ras(struct ast_channel *chan, char *args)
00141 {
00142    pid_t pid;
00143    int status;
00144    int res;
00145    int signalled = 0;
00146    struct zt_bufferinfo savebi;
00147    int x;
00148    
00149    res = ioctl(chan->fds[0], ZT_GET_BUFINFO, &savebi);
00150    if(res) {
00151       ast_log(LOG_WARNING, "Unable to check buffer policy on channel %s\n", chan->name);
00152       return;
00153    }
00154 
00155    pid = spawn_ras(chan, args);
00156    if (pid < 0) {
00157       ast_log(LOG_WARNING, "Failed to spawn RAS\n");
00158    } else {
00159       for (;;) {
00160          res = wait4(pid, &status, WNOHANG, NULL);
00161          if (!res) {
00162             /* Check for hangup */
00163             if (chan->_softhangup && !signalled) {
00164                ast_log(LOG_DEBUG, "Channel '%s' hungup.  Signalling RAS at %d to die...\n", chan->name, pid);
00165                kill(pid, SIGTERM);
00166                signalled=1;
00167             }
00168             /* Try again */
00169             sleep(1);
00170             continue;
00171          }
00172          if (res < 0) {
00173             ast_log(LOG_WARNING, "wait4 returned %d: %s\n", res, strerror(errno));
00174          }
00175          if (option_verbose > 2) {
00176             if (WIFEXITED(status)) {
00177                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated with status %d\n", chan->name, WEXITSTATUS(status));
00178             } else if (WIFSIGNALED(status)) {
00179                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated with signal %d\n", 
00180                    chan->name, WTERMSIG(status));
00181             } else {
00182                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated weirdly.\n", chan->name);
00183             }
00184          }
00185          /* Throw back into audio mode */
00186          x = 0;
00187          ioctl(chan->fds[0], ZT_AUDIOMODE, &x);
00188 
00189          /* Restore saved values */
00190          res = ioctl(chan->fds[0], ZT_SET_BUFINFO, &savebi);
00191          if (res < 0) {
00192             ast_log(LOG_WARNING, "Unable to set buffer policy on channel %s\n", chan->name);
00193          }
00194          break;
00195       }
00196    }
00197 }
00198 
00199 static int zapras_exec(struct ast_channel *chan, void *data)
00200 {
00201    int res=-1;
00202    char *args;
00203    struct ast_module_user *u;
00204    ZT_PARAMS ztp;
00205 
00206    if (!data) 
00207       data = "";
00208 
00209    u = ast_module_user_add(chan);
00210 
00211    args = ast_strdupa(data);
00212    
00213    /* Answer the channel if it's not up */
00214    if (chan->_state != AST_STATE_UP)
00215       ast_answer(chan);
00216    if (strcasecmp(chan->tech->type, "Zap")) {
00217       /* If it's not a zap channel, we're done.  Wait a couple of
00218          seconds and then hangup... */
00219       if (option_verbose > 1)
00220          ast_verbose(VERBOSE_PREFIX_2 "Channel %s is not a Zap channel\n", chan->name);
00221       sleep(2);
00222    } else {
00223       memset(&ztp, 0, sizeof(ztp));
00224       if (ioctl(chan->fds[0], ZT_GET_PARAMS, &ztp)) {
00225          ast_log(LOG_WARNING, "Unable to get zaptel parameters\n");
00226       } else if (ztp.sigtype != ZT_SIG_CLEAR) {
00227          if (option_verbose > 1)
00228             ast_verbose(VERBOSE_PREFIX_2 "Channel %s is not a clear channel\n", chan->name);
00229       } else {
00230          /* Everything should be okay.  Run PPP. */
00231          if (option_verbose > 2)
00232             ast_verbose(VERBOSE_PREFIX_3 "Starting RAS on %s\n", chan->name);
00233          /* Execute RAS */
00234          run_ras(chan, args);
00235       }
00236    }
00237    ast_module_user_remove(u);
00238    return res;
00239 }
00240 
00241 static int unload_module(void) 
00242 {
00243    int res;
00244 
00245    res = ast_unregister_application(app);
00246    
00247    ast_module_user_hangup_all();
00248 
00249    return res;
00250 }
00251 
00252 static int load_module(void)
00253 {
00254    return ast_register_application(app, zapras_exec, synopsis, descrip);
00255 }
00256 
00257 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Zap RAS Application");
00258 

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