/* A Linux-based Telephone Answering Machine * Copyright:     Bob Smith, 2005 * Warranty:      No warranty expressed or implied. USE AT YOUR OWN RISK! * License:       GNU General Public License, version 2 *                See http://www.gnu.org/copyleft/gpl.html for full text * Documentation: http://www.linuxtoys.org/answer/answering_machine.html * Version:       1.0.0 2005-Sep-20, Initial release * REQUIREMENTS: *  - Intel 537 based softmodem *  - A PCI slot that does not share interrupts *  - Linux 2.6 with gcc and sox installed * INSTALLATION: *  1) Install the zaptel drivers from Asterisk *  2) Install the Zapata library from Asterisk *  3) Record a greeting asking the caller to press 1 to *     leave a message.  Convert the WAV file to mu-law using: *     sox leave_a_msg.wav leave_a_msg.ul *  4) Compile the program using: *     gcc -lzap -o answering_machine answering_machine.c * USAGE: *  There are no command line options.  Invoke the program with: *     ./answering_machine *  Voice mail files can be heard using the 'play' utility from *  the sox package.  For example: *     play 2005_09_22_14_37_03.ul * By-the-way: *  The zap_xxx() calls in this program are well documented in * zap.c in the Zapata source directory. */#include <stdio.h>#include <zap.h>#include <errno.h>#include <time.h>        /* The number of rings to wait before answering */#define RINGS   (4)        /* DTMF digit you ask the caller to press to leave a msg */#define PLEASE_ENTER '1'        /* The time (ms) to wait for a "1" from the caller */#define TM_OUT  (9000)        /* The maximum size of a string in this program */#define STRMX   (65)        /* A generic error collection subroutine */void err_if(int, char, int, int);        /* The handle to the open telephone interface */ZAP     *zp;main(){  int        result;            /* return code from Zapata call */  char      *pDigits;           /* points to entered DTMF digits */  char       cidnumber[STRMX];  /* Caller-ID phone number */  char       cidname[STRMX];    /* Caller-ID name */  char       date_time[STRMX];  /* date and time from strftime() */  struct tm *ptm;               /* date and time in tm structure */  time_t     now;               /* Current time in seconds */  zp = zap_open("/dev/zap/1", 0);  if (!zp) {    printf("Unable to open /dev/zap/1.  Please verify that the\n");    printf("zaptel and wcfxo modules are installed, and that your\n");    printf("hardware is installed and working correctly.\n");    exit(1);  }  while (1) {    /* Wait for a ring and get caller ID info */    result = zap_clid(zp, cidnumber, cidname);    err_if(result, '=', -1, __LINE__);   /* error if -1 */    if (result == -2) {                  /* internal error getting CLID */      cidnumber[0] = (char) 0;           /* happens on quick user pick-up */      strncpy(cidname, "(invalid caller ID)", STRMX-1);    }    /* Print date, time, and caller ID info */    date_time[0] = (char) 0;    now = time((time_t *) 0);    ptm = localtime(&now);    err_if((int)ptm, '=', 0, __LINE__);  /* error if zero */    (void) strftime(date_time, 63, "%T", ptm);    printf("%s  %s %s  ", date_time, cidnumber, cidname);    fflush(stdout);    /* Wait for an additional RINGS-1 rings before answering */    result = zap_waitcall(zp, (RINGS - 1), ZAP_OFFHOOK, (TM_OUT/1000));    if (result == -1 && errno == EINTR) {      printf("\n");                      /* local user picked-up */      continue;    }    err_if(result, '!', 0, __LINE__);    /* error if not zero */    /* Init the digit buffer and tell Zapata that we want DTMF digits */    (void) zap_clrdtmfn(zp);    result = zap_digitmode(zp, ZAP_DTMF) && zap_clrdtmf(zp);    err_if(result, '!', 0, __LINE__);    /* error if not zero */    /* Play our outgoing message.  Abort on DTMF or hang-up. */    result = zap_playf(zp, "leave_a_msg.ul", ZAP_DTMFINT | ZAP_HOOKEXIT);    err_if(result, '=', -1, __LINE__);   /* error if -1 */    if (result == -2) {                  /* == -2 on caller hang-up */      printf("\n");      zap_sethook(zp, ZAP_ONHOOK);      continue;    }    /* Wait up to TM_OUT ms for the caller to enter a DTMF digit */    result = zap_getdtmf(zp, 1, (char *)0, 0, 0, TM_OUT, ZAP_HOOKEXIT);    err_if(result, '=', -1, __LINE__);   /* error if -1 */    /* Hang-up if time-out and no DTMF digit.  (Bulk dialer?) */    if (result != 1) {      printf("\n");      zap_sethook(zp, ZAP_ONHOOK);      err_if(result, '=', -1, __LINE__); /* error if -1 */      continue;    }    /* Get the DTMF digit the caller entered.  Hang-up if wrong digit */    pDigits = zap_dtmfbuf(zp);    if ((!pDigits) || (*pDigits != PLEASE_ENTER)) {      printf("\n");      zap_sethook(zp, ZAP_ONHOOK);      err_if(result, '=', -1, __LINE__); /* error if -1 */      continue;    }    printf("************\n");  /* Tell local user of voice mail */    /* Create voice mail file: YYYY_MM_DD_HH_mm_SS.ul */    (void) strftime(date_time, 63, "%G_%m_%d_%H_%M_%S.ul", ptm);    result = zap_recf(zp, date_time, 0,               ZAP_BEEPTONE | ZAP_HOOKEXIT | ZAP_SILENCEINT);    err_if(result, '=', -1, __LINE__);   /* error if -1 */    /* Done with message.  Hang-up and wait for next call. */    result = zap_sethook(zp, ZAP_ONHOOK);    err_if(result, '=', -1, __LINE__);   /* error if -1 */  }  exit(0);  /* not reached */}/* err_if() -- Exit the program if the result is not correct. * Inputs are the result, the comparison operator, the value * to match, and the line number */void err_if(int result, char operator, int errval, int linenum){  if (((operator == '=') && (result == errval)) ||      ((operator == '!') && (result != errval))) {    printf("Error code %d at line = %d, with errno = %d.   Bye...\n",           result, linenum, errno);    (void) zap_sethook(zp, ZAP_ONHOOK);    exit(1);  }}