1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
|
/*
* 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);
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
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;
}
}
|