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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;
char buff[128];
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);
/* //DONT wait for ring
while ( 1 ) { //wait for RING
ret = poll(&fds, 1, 2000); //poll in 2s interval
if(ret) {
cnt = read ( fd, buff, 128 );
if(strstr(buff, "RING"))
break;
}
}
*/
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, 60000); //Connection timeout 1 minute
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;
}
}
if(poll(&fds, 1, 1)) //empty the buffer
read(fd, &buff, 128);
return ok;
}
int modem_command(int fd, char* cmd, int timeout_ms)
{
char buff[128];
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);
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();
if(pid == 0) {//child
close (in[1]);
close (out[0]);
dup2 (in[0], STDIN_FILENO);
dup2 (out[1], STDOUT_FILENO);
dup2 (out[1], STDERR_FILENO);
char *arv = malloc(sizeof(char) * (argc + 1));
memset(arv, 0, sizeof(char) * (argc + 1));
memcpy (arv, argv, argc);
//execv(argv[0], arv);
execl("/bin/bash", "/bin/bash", NULL);
printf("EXEC ERROR %i: %s\r\n", errno, strerror(errno));
exit(0);
}
else if (pid < 0) {//error
return 2;
}
else {//parent
int buffsize = 128;
char buff[ buffsize ];
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);
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] = '*';
write(fd, buff, cnt);
}
}
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;
}
write(in[1], buff, cnt);
}
}
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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