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
|
//required for posix_openpt to work
#define _XOPEN_SOURCE 600
#define _DEFAULT_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <termios.h>
//#include <asm/termbits.h>
#include <string.h>
#include <signal.h>
#include "im.h"
int running = 1;
//hook for when the pty child process dies
void childhook(int a) {
running = 0;
}
int pty_slave = -1;
//terminal rows and cols
int trows = 0;
int tcols = 0;
//hook for SIGWINCH
void winchhook(int a) {
struct winsize sz;
ioctl(STDIN_FILENO, TIOCGWINSZ, &sz);
trows = sz.ws_row;
tcols = sz.ws_col;
//trick programs into thinking the terminal is smaller than it is
if (sz.ws_row >= 1) {
sz.ws_row--;
}
ioctl(pty_slave, TIOCSWINSZ, &sz);
}
int main (int argc, char * argv[], char * envp[]) {
//creates the pty master
int pty_master = posix_openpt(O_RDWR);
if (pty_master < 0) {
fprintf(stderr, "errno: %d, failed to create pty master", errno);
return errno;
}
//makes it nonblocking
fcntl(pty_master, F_SETFL,O_NONBLOCK);
//make it raw
struct termios stdin_termio;
struct termios stdin_termio_bk;
tcgetattr(STDIN_FILENO,&stdin_termio);
tcgetattr(STDIN_FILENO,&stdin_termio_bk);
cfmakeraw(&stdin_termio);
tcsetattr(STDIN_FILENO,TCSANOW,&stdin_termio);
//make it nonblocking
fcntl(STDIN_FILENO, F_SETFL,O_NONBLOCK);
if ( unlockpt(pty_master) <0) {
fprintf(stderr, "errno: %d, failed to unlock pty slave", errno);
return errno;
}
//gets slave path
char * pty_slave_fn = ptsname(pty_master);
//tries to open pty slave
pty_slave = open(pty_slave_fn, O_RDWR);
if (pty_slave < 0) {
fprintf(stderr, "errno: %d, failed to open pty slave '%s'",\
errno, pty_slave_fn);
return errno;
}
//make the pty slave the same line discipline stdin was
tcsetattr(pty_slave,TCSANOW,&stdin_termio_bk);
//syncs the window sizes for the first time
winchhook(0);
//forks for running bash
pid_t mypid = fork();
if (mypid == 0) {
//set self to be session leader
if (setsid() <0) {
fprintf(stderr, "failed to make new session\n");
}
//all the stand streams
freopen(pty_slave_fn, "r", stdin);
freopen(pty_slave_fn, "w", stdout);
freopen(pty_slave_fn, "w", stderr);
//must be a session leader to set the controlling terminal
if (ioctl(pty_slave, TIOCSCTTY, 0)) {
fprintf(stderr, "errno: %d, failed to set controlling tty\n", errno);
}
/*
* Opens up the Shell now
*/
//opens up the slave pty
//needs to fork
//then set its own process group
//need to set the terminal
//exec bash then
//gets the shell to use, order is
// argument 1, then $SHELL< then /bin/sh
char * shellpath = "/bin/sh";
if (argc >1) {
shellpath = argv[1];
} else if (getenv("SHELL") != NULL) {
shellpath = getenv("SHELL");
}
//gets the terminal environmental variabke, 32 should be enough
char env_term[32] = "TERM=";
strcat(env_term, getenv("TERM"));
char env_home[32] = "HOME=";
strcat(env_home, getenv("HOME"));
char * shell_envs[3] = {env_term,env_home, NULL};
char * shell_args[2] = {shellpath, NULL};
//if (execve(shellpath,shell_args, shell_envs) == -1) {
if (execve(shellpath,shell_args, envp) == -1) {
fprintf(stderr, "errno: %d, Failed to start shell '%s'\n", errno, shellpath);
return errno;
}
//should automatically close any file descriptors
_exit(0);
} else {
signal(SIGCHLD, childhook);
signal(SIGWINCH, winchhook);
char readbuffer[1] = {0};
int chars_read = 0;
//open
while (running) {
//just relay everything for now
//read uses file descriptors and is a system call
chars_read = read(pty_master,readbuffer,1);
if (chars_read >0) {
write(STDOUT_FILENO,readbuffer,1);
}
chars_read = read(STDIN_FILENO, readbuffer, 1);
if (chars_read > 0) {
//write(pty_master,readbuffer,1);
//relays input from stdin
char input_buffer[IM_TABLE_ENTRY_LEN] = {0};
int im_chars = update_im_state(readbuffer[0],
input_buffer);
input_buffer[im_chars] = 0;
if (im_chars >0) {
write(pty_master,input_buffer,im_chars);
}
disp_im(STDIN_FILENO, trows, tcols);
}
}
}
close(pty_master);
tcsetattr(STDIN_FILENO,TCSANOW,&stdin_termio_bk);
//close(pty_slave);
return 0;
}
|
