Sat Sep 16 05:47:41 2006

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: 37419 $")
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    /* Drop high priority */
00100    if (option_highpriority)
00101       ast_set_priority(0);
00102 
00103    /* Close other file descriptors */
00104    for (x=STDERR_FILENO + 1;x<1024;x++) 
00105       close(x);
00106 
00107    /* Restore original signal handlers */
00108    for (x=0;x<NSIG;x++)
00109       signal(x, SIG_DFL);
00110 
00111    /* Reset all arguments */
00112    memset(argv, 0, sizeof(argv));
00113 
00114    /* First argument is executable, followed by standard
00115       arguments for zaptel PPP */
00116    argv[argc++] = PPP_EXEC;
00117    argv[argc++] = "nodetach";
00118 
00119    /* And all the other arguments */
00120    stringp=args;
00121    c = strsep(&stringp, "|");
00122    while(c && strlen(c) && (argc < (PPP_MAX_ARGS - 4))) {
00123       argv[argc++] = c;
00124       c = strsep(&stringp, "|");
00125    }
00126 
00127    argv[argc++] = "plugin";
00128    argv[argc++] = "zaptel.so";
00129    argv[argc++] = "stdin";
00130 
00131    /* Finally launch PPP */
00132    execv(PPP_EXEC, argv);
00133    fprintf(stderr, "Failed to exec PPPD!\n");
00134    exit(1);
00135 }
00136 
00137 static void run_ras(struct ast_channel *chan, char *args)
00138 {
00139    pid_t pid;
00140    int status;
00141    int res;
00142    int signalled = 0;
00143    struct zt_bufferinfo savebi;
00144    int x;
00145    
00146    res = ioctl(chan->fds[0], ZT_GET_BUFINFO, &savebi);
00147    if(res) {
00148       ast_log(LOG_WARNING, "Unable to check buffer policy on channel %s\n", chan->name);
00149       return;
00150    }
00151 
00152    pid = spawn_ras(chan, args);
00153    if (pid < 0) {
00154       ast_log(LOG_WARNING, "Failed to spawn RAS\n");
00155    } else {
00156       for (;;) {
00157          res = wait4(pid, &status, WNOHANG, NULL);
00158          if (!res) {
00159             /* Check for hangup */
00160             if (chan->_softhangup && !signalled) {
00161                ast_log(LOG_DEBUG, "Channel '%s' hungup.  Signalling RAS at %d to die...\n", chan->name, pid);
00162                kill(pid, SIGTERM);
00163                signalled=1;
00164             }
00165             /* Try again */
00166             sleep(1);
00167             continue;
00168          }
00169          if (res < 0) {
00170             ast_log(LOG_WARNING, "wait4 returned %d: %s\n", res, strerror(errno));
00171          }
00172          if (option_verbose > 2) {
00173             if (WIFEXITED(status)) {
00174                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated with status %d\n", chan->name, WEXITSTATUS(status));
00175             } else if (WIFSIGNALED(status)) {
00176                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated with signal %d\n", 
00177                    chan->name, WTERMSIG(status));
00178             } else {
00179                ast_verbose(VERBOSE_PREFIX_3 "RAS on %s terminated weirdly.\n", chan->name);
00180             }
00181          }
00182          /* Throw back into audio mode */
00183          x = 1;
00184          ioctl(chan->fds[0], ZT_AUDIOMODE, &x);
00185 
00186          /* Restore saved values */
00187          res = ioctl(chan->fds[0], ZT_SET_BUFINFO, &savebi);
00188          if (res < 0) {
00189             ast_log(LOG_WARNING, "Unable to set buffer policy on channel %s\n", chan->name);
00190          }
00191          break;
00192       }
00193    }
00194 }
00195 
00196 static int zapras_exec(struct ast_channel *chan, void *data)
00197 {
00198    int res=-1;
00199    char *args;
00200    struct localuser *u;
00201    ZT_PARAMS ztp;
00202 
00203    if (!data) 
00204       data = "";
00205 
00206    LOCAL_USER_ADD(u);
00207 
00208    args = ast_strdupa(data);
00209    if (!args) {
00210       ast_log(LOG_ERROR, "Out of memory\n");
00211       LOCAL_USER_REMOVE(u);
00212       return -1;
00213    }
00214    
00215    /* Answer the channel if it's not up */
00216    if (chan->_state != AST_STATE_UP)
00217       ast_answer(chan);
00218    if (strcasecmp(chan->type, "Zap")) {
00219       /* If it's not a zap channel, we're done.  Wait a couple of
00220          seconds and then hangup... */
00221       if (option_verbose > 1)
00222          ast_verbose(VERBOSE_PREFIX_2 "Channel %s is not a Zap channel\n", chan->name);
00223       sleep(2);
00224    } else {
00225       memset(&ztp, 0, sizeof(ztp));
00226       if (ioctl(chan->fds[0], ZT_GET_PARAMS, &ztp)) {
00227          ast_log(LOG_WARNING, "Unable to get zaptel parameters\n");
00228       } else if (ztp.sigtype != ZT_SIG_CLEAR) {
00229          if (option_verbose > 1)
00230             ast_verbose(VERBOSE_PREFIX_2 "Channel %s is not a clear channel\n", chan->name);
00231       } else {
00232          /* Everything should be okay.  Run PPP. */
00233          if (option_verbose > 2)
00234             ast_verbose(VERBOSE_PREFIX_3 "Starting RAS on %s\n", chan->name);
00235          /* Execute RAS */
00236          run_ras(chan, args);
00237       }
00238    }
00239    LOCAL_USER_REMOVE(u);
00240    return res;
00241 }
00242 
00243 int unload_module(void)
00244 {
00245    int res;
00246 
00247    res = ast_unregister_application(app);
00248    
00249    STANDARD_HANGUP_LOCALUSERS;
00250 
00251    return res;
00252 }
00253 
00254 int load_module(void)
00255 {
00256    return ast_register_application(app, zapras_exec, synopsis, descrip);
00257 }
00258 
00259 char *description(void)
00260 {
00261    return tdesc;
00262 }
00263 
00264 int usecount(void)
00265 {
00266    int res;
00267    STANDARD_USECOUNT(res);
00268    return res;
00269 }
00270 
00271 char *key()
00272 {
00273    return ASTERISK_GPL_KEY;
00274 }

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