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/*
* modem.c
* (c) 2019, Jonas Gunz, jonasgunz.de
* <Description>
* <License>
*/
#include "modem.h"
int modem_accept_wait(int fd)
{
if(!fd)
return 1;
int buffsize = 128;
char buff[ buffsize + 1];
buff[buffsize] = '\0';
int ret; //for retturn values
struct pollfd fds; //poll struct
int cnt = 0; //read byte counter
fds.fd = fd;
fds.events = POLLIN;
modem_command(fd, _AT_ECHO_OFF, 1000);
modem_command(fd, _AT_MUTE, 1000);
modem_command(fd, _AT_RESET_ON_DTR, 1000);
#ifdef _MODEM_WAIT_RING
while ( 1 ) { //wait for RING
ret = poll(&fds, 1, 2000); //poll in 2s interval
usleep(5000);
if(ret) {
cnt = read ( fd, buff, 128 );
if(strstr(buff, "RING"))
break;
}
}
#else
#warning "Wait for RING disabled"
#endif
printf("Modem RINGING\n");
int ok = 5;
int timeout = 60000;
write (fd, _AT_ANSWER, strlen(_AT_ANSWER)); //Accept incoming call
cnt = 0;
while(1)
{
ret = poll(&fds, 1, timeout); //Connection timeout 1 minute
usleep(5000); //Wait for data
if(!ret)
break;
if(cnt >= 128)
break;
cnt += read (fd, &buff[cnt - 1], 128 - cnt + 1);
printf("%s\n", buff);
if(strstr(buff, "CONNECT")){
ok = 0;
break;
}
else if(strstr(buff, "NO CARRIER")) //Don't timeout on error
break;
}
if(poll(&fds, 1, 1)) //empty the buffer
read(fd, &buff, 128);
return ok;
}
int modem_command(int fd, char* cmd, int timeout_ms)
{
int buffsize = 128;
char buff[ buffsize + 1];
buff[buffsize] = '\0';
int ret; //for retturn values
struct pollfd fds; //poll struct
int cnt = 0; //read byte counter
fds.fd = fd;
fds.events = POLLIN;
write(fd, cmd, strlen(cmd) );
int ok = 1;
while(1) {
ret = poll(&fds, 1, timeout_ms);
usleep(5000); //Wait for data to fully come in
if (ret)
cnt += read(fd, &buff[cnt - 1], 128 - cnt + 1);
else
break;
if(cnt >= 128)
break;
if( strstr(buff, "OK") ) {
ok = 0;
break;
}
}
if(poll(&fds, 1, 1)) //Empty the buffer
read(fd, &buff, 128);
printf("Command %s: %s\n", cmd, ok ? "FAIL" : "OK");
return ok;
}
int modem_run(int fd, int argc, char* argv[])
{
int in[2];
int out[2];
//1: write, 0: read
if(pipe(in) == -1)
return 1;
if(pipe(out) == -1)
return 1;
pid_t pid = fork_run(in[0], out[1], out[1], argc, argv);//fork();
if (pid < 0) {//error
return 2;
}
int buffsize = 128;
char buff[ buffsize + 1];
buff[buffsize] = '\0';
close (in[0]);
close (out[1]);
//setup poll to listen for input
struct pollfd fds[2];
fds[0].fd = out[0];
fds[0].events = POLLIN;
fds[1].fd = fd;
fds[1].events = POLLIN;
printf("Forked with PID %i\n", pid);
while(1)
{
int ret = poll (fds, 2, 100);
usleep(5000); //Wait for data to fully come in, helps prevent truncation of status returns which helps with parsing
if ( fds[0].revents & POLLIN ) {
int cnt = read (out[0], buff, buffsize);
if(cnt) {
//replace +++ to not trigger modem command mode
char *str = strstr(buff, "+++");
if(str)
str[1] = '*';
if(try_write(fd, buff, cnt, 100)) {
printf("Consecutive write errors while writing to serial device.\n");
break;
}
}
}
if ( fds[1].revents & POLLIN ) {
int cnt = read (fd, buff, buffsize);
if(cnt) {
//search for modem error message
char *str = strstr(buff, "NO CARRIER");
if(str){ //Exit if message found
kill(pid,SIGTERM);
break;
}
if(try_write(in[1], buff, cnt, 100)) {
printf("Consecutive write errors while writing to STDIN.\n");
break;
}
}
}
if(ret < 0)
break;
if(kill(pid,0)) //Check if child is still alive, if not return.
break;
}
printf("Connection closed.\n");
close(fd); //Auto closes connection
return 0;
}
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