From b4582f3209a4916ffaa54baa716ab27a87bb961a Mon Sep 17 00:00:00 2001
From: Jonas Gunz <himself@jonasgunz.de>
Date: Thu, 27 Jun 2019 23:08:01 +0200
Subject: can accept incoming calls

---
 src/modem.c | 147 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 147 insertions(+)
 create mode 100644 src/modem.c

(limited to 'src/modem.c')

diff --git a/src/modem.c b/src/modem.c
new file mode 100644
index 0000000..b2e7dbd
--- /dev/null
+++ b/src/modem.c
@@ -0,0 +1,147 @@
+/*
+ * 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;
+
+	write(fd, _AT_ECHO_OFF, strlen(_AT_ECHO_OFF) );
+
+	int ok = 0;
+	while(1) {
+		ret = poll(&fds, 1, 1000);
+		if (ret)
+			cnt = read(fd, buff, 128); //Dummy read from _AT_ECHO_OFF, should say OK
+		else 
+			break;
+
+
+		if( strstr(buff, "OK") )
+			ok = 1;
+	}
+
+	if(! ok )
+		return 3;
+
+	printf("Modem OK\n");
+
+	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");
+
+	write (fd, _AT_ANSWER, strlen(_AT_ANSWER)); //Accept incoming call
+	ret = poll(&fds, 1, 30000);
+	if(ret) {
+		cnt = read (fd, buff, 128);
+		if(strstr(buff, "CONNECT"))
+			return 0;
+		else
+			return 4;
+	}
+
+	return 5;
+}
+
+int modem_hang(int fd)
+{
+}
+
+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);
+		
+		printf("EXEC ERROR\n\n");
+		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;
+
+		while(1)
+		{
+			int ret = poll (fds, 2, 100);
+
+			if ( fds[0].revents & POLLIN ) {
+				int cnt = read (out[0], buff, buffsize);
+				if(cnt) {
+					while(1) { //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) {
+					while(1) { //search for modem error message
+						char *str = strstr(buff, "NO CARRIER");
+						if(str) { //Exit if message found
+							return 0;
+						}
+					}
+
+					write(in[1], buff, cnt);
+				}
+			}
+
+			if(kill(pid,0)) //Check if child is still alive, if not return.
+				return 0;
+		}
+	}
+
+}
-- 
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