1 #include <u.h>
2 #include <signal.h>
3 #include <libc.h>
4 #include "term.h"
5 
6 int loginshell;
7 
8 static void
9 sys(char *buf, int devnull)
10 {
11 	char buf2[100];
12 	char *f[20];
13 	int nf, pid;
14 
15 	notedisable("sys: child");
16 	strcpy(buf2, buf);
17 	nf = tokenize(buf2, f, nelem(f));
18 	f[nf] = nil;
19 	switch(pid = fork()){
20 	case 0:
21 		close(1);
22 		open("/dev/null", OREAD);
23 		close(2);
24 		open("/dev/null", OREAD);
25 		execvp(f[0], f);
26 		_exit(2);
27 	default:
28 		waitpid();
29 		noteenable("sys: child");
30 	}
31 }
32 
33 int
34 rcstart(int argc, char **argv, int *pfd, int *tfd)
35 {
36 	int fd[2], i, pid;
37 	char *cmd, *xargv[3];
38 	char slave[256];
39 	int sfd;
40 
41 	if(argc == 0){
42 		argc = 2;
43 		argv = xargv;
44 		argv[0] = getenv("SHELL");
45 		if(argv[0] == 0)
46 			argv[0] = "rc";
47 		argv[1] = "-i";
48 		argv[2] = 0;
49 	}
50 	cmd = argv[0];
51 	if(loginshell){
52 		argv[0] = malloc(strlen(cmd)+2);
53 		strcpy(argv[0]+1, cmd);
54 		argv[0][0] = '-';
55 	}
56 
57 	/*
58 	 * fd0 is slave (tty), fd1 is master (pty)
59 	 */
60 	fd[0] = fd[1] = -1;
61 	if(getpts(fd, slave) < 0){
62 		exit(3);
63 		sysfatal("getpts: %r\n");
64 	}
65 	/*
66 	 * notedisable("sys: window size change");
67 	 * 
68 	 * Can't disable because will be inherited by other programs
69 	 * like if you run an xterm from the prompt, and then xterm's
70 	 * resizes won't get handled right.  Sigh.  
71 	 *
72 	 * Can't not disable because when we stty below we'll get a
73 	 * signal, which will drop us into the thread library note handler,
74 	 * which will get all confused because we just forked and thus
75 	 * have an unknown pid. 
76 	 *
77 	 * So disable it internally.  ARGH!
78 	 */
79 	notifyoff("sys: window size change");
80 
81 	// This used to be TERM=9term but we don't know of anything that cares.
82 	// Worse, various cc have started assuming that TERM != dumb implies
83 	// the ability to understand ANSI escape codes. 9term will squelch them
84 	// but acme win does not.
85 	putenv("TERM", "dumb");
86 
87 	// Set $termprog to 9term or win for those who care about what kind of
88 	// dumb terminal this is.
89 	putenv("termprog", (char*)termprog);
90 
91 	pid = fork();
92 	switch(pid){
93 	case 0:
94 		sfd = childpty(fd, slave);
95 		dup(sfd, 0);
96 		dup(sfd, 1);
97 		dup(sfd, 2);
98 		sys("stty tabs -onlcr icanon echo erase '^h' intr '^?'", 0);
99 		sys("stty onocr", 1);	/* not available on mac */
100 		for(i=3; i<100; i++)
101 			close(i);
102 		signal(SIGINT, SIG_DFL);
103 		signal(SIGHUP, SIG_DFL);
104 		signal(SIGTERM, SIG_DFL);
105 		execvp(cmd, argv);
106 		fprint(2, "exec %s failed: %r\n", argv[0]);
107 		_exit(2);
108 		break;
109 	case -1:
110 		sysfatal("proc failed: %r");
111 		break;
112 	}
113 	*pfd = fd[1];
114 	close(fd[0]);
115 	if(tfd){
116 		if((*tfd = open(slave, OREAD)) < 0)
117 			sysfatal("parent open %s: %r", slave);
118 	}
119 	return pid;
120 }
121 
122 struct {
123 	Lock l;
124 	char buf[1<<20];
125 	int r, w;
126 } echo;
127 
128 void
129 echoed(char *p, int n)
130 {
131 	lock(&echo.l);
132 	if(echo.r > 0) {
133 		memmove(echo.buf, echo.buf+echo.r, echo.w-echo.r);
134 		echo.w -= echo.r;
135 		echo.r = 0;
136 	}
137 	if(echo.w+n > sizeof echo.buf)
138 		echo.r = echo.w = 0;
139 	if(echo.w+n > sizeof echo.buf)
140 		n = 0;
141 	memmove(echo.buf+echo.w, p, n);
142 	echo.w += n;	
143 	unlock(&echo.l);
144 }
145 
146 int
147 echocancel(char *p, int n)
148 {
149 	int i;
150 
151 	lock(&echo.l);
152 	for(i=0; i<n; i++) {
153 		if(echo.r < echo.w) {
154 			if(echo.buf[echo.r] == p[i]) {
155 				echo.r++;
156 				continue;
157 			}
158 			if(echo.buf[echo.r] == '\n' && p[i] == '\r')
159 				continue;
160 			if(p[i] == 0x08) {
161 				if(i+2 <= n && p[i+1] == ' ' && p[i+2] == 0x08)
162 					i += 2;
163 				continue;
164 			}
165 		}
166 		echo.r = echo.w;
167 		break;
168 	}
169 	unlock(&echo.l);
170 	if(i > 0)
171 		memmove(p, p+i, n-i);
172 	return n-i;
173 }
174 
175 int
176 dropcrnl(char *p, int n)
177 {
178 	char *r, *w;
179 
180 	for(r=w=p; r<p+n; r++) {
181 		if(r+1<p+n && *r == '\r' && *(r+1) == '\n')
182 			continue;
183 		if(*r == 0x08) {
184 			if(r+2<=p+n && *(r+1) == ' ' && *(r+2) == 0x08)
185 				r += 2;
186 			continue;
187 		}
188 		*w++ = *r;
189 	}
190 	return w-p;
191 }