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