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[4];
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 		if(loginshell){
50 			argv[2] = "-l";
51 			argv[3] = 0;
52 			argc = 3;
53 		}
54 	}
55 	cmd = argv[0];
56 	if(loginshell){
57 		argv[0] = malloc(strlen(cmd)+2);
58 		strcpy(argv[0]+1, cmd);
59 		argv[0][0] = '-';
60 	}
61 
62 	/*
63 	 * fd0 is slave (tty), fd1 is master (pty)
64 	 */
65 	fd[0] = fd[1] = -1;
66 	if(getpts(fd, slave) < 0){
67 		exit(3);
68 		sysfatal("getpts: %r\n");
69 	}
70 	/*
71 	 * notedisable("sys: window size change");
72 	 *
73 	 * Can't disable because will be inherited by other programs
74 	 * like if you run an xterm from the prompt, and then xterm's
75 	 * resizes won't get handled right.  Sigh.
76 	 *
77 	 * Can't not disable because when we stty below we'll get a
78 	 * signal, which will drop us into the thread library note handler,
79 	 * which will get all confused because we just forked and thus
80 	 * have an unknown pid.
81 	 *
82 	 * So disable it internally.  ARGH!
83 	 */
84 	notifyoff("sys: window size change");
85 
86 	// This used to be TERM=9term but we don't know of anything that cares.
87 	// Worse, various cc have started assuming that TERM != dumb implies
88 	// the ability to understand ANSI escape codes. 9term will squelch them
89 	// but acme win does not.
90 	putenv("TERM", "dumb");
91 
92 	// Set $termprog to 9term or win for those who care about what kind of
93 	// dumb terminal this is.
94 	putenv("termprog", (char*)termprog);
95 	putenv("TERM_PROGRAM", (char*)termprog);
96 
97 	pid = fork();
98 	switch(pid){
99 	case 0:
100 		sfd = childpty(fd, slave);
101 		dup(sfd, 0);
102 		dup(sfd, 1);
103 		dup(sfd, 2);
104 		sys("stty tabs -onlcr icanon echo erase '^h' intr '^?'", 0);
105 		sys("stty onocr", 1);	/* not available on mac */
106 		for(i=3; i<100; i++)
107 			close(i);
108 		signal(SIGINT, SIG_DFL);
109 		signal(SIGHUP, SIG_DFL);
110 		signal(SIGTERM, SIG_DFL);
111 		execvp(cmd, argv);
112 		fprint(2, "exec %s failed: %r\n", argv[0]);
113 		_exit(2);
114 		break;
115 	case -1:
116 		sysfatal("proc failed: %r");
117 		break;
118 	}
119 	*pfd = fd[1];
120 	close(fd[0]);
121 	if(tfd){
122 		if((*tfd = open(slave, OREAD)) < 0)
123 			sysfatal("parent open %s: %r", slave);
124 	}
125 	return pid;
126 }
127 
128 struct {
129 	Lock l;
130 	char buf[1<<20];
131 	int r, w;
132 } echo;
133 
134 void
135 echoed(char *p, int n)
136 {
137 	lock(&echo.l);
138 	if(echo.r > 0) {
139 		memmove(echo.buf, echo.buf+echo.r, echo.w-echo.r);
140 		echo.w -= echo.r;
141 		echo.r = 0;
142 	}
143 	if(echo.w+n > sizeof echo.buf)
144 		echo.r = echo.w = 0;
145 	if(echo.w+n > sizeof echo.buf)
146 		n = 0;
147 	memmove(echo.buf+echo.w, p, n);
148 	echo.w += n;
149 	unlock(&echo.l);
150 }
151 
152 int
153 echocancel(char *p, int n)
154 {
155 	int i;
156 
157 	lock(&echo.l);
158 	for(i=0; i<n; i++) {
159 		if(echo.r < echo.w) {
160 			if(echo.buf[echo.r] == p[i]) {
161 				echo.r++;
162 				continue;
163 			}
164 			if(echo.buf[echo.r] == '\n' && p[i] == '\r')
165 				continue;
166 			if(p[i] == 0x08) {
167 				if(i+2 <= n && p[i+1] == ' ' && p[i+2] == 0x08)
168 					i += 2;
169 				continue;
170 			}
171 		}
172 		echo.r = echo.w;
173 		break;
174 	}
175 	unlock(&echo.l);
176 	if(i > 0)
177 		memmove(p, p+i, n-i);
178 	return n-i;
179 }
180 
181 int
182 dropcrnl(char *p, int n)
183 {
184 	char *r, *w;
185 
186 	for(r=w=p; r<p+n; r++) {
187 		if(r+1<p+n && *r == '\r' && *(r+1) == '\n')
188 			continue;
189 		if(*r == 0x08) {
190 			if(r+2<=p+n && *(r+1) == ' ' && *(r+2) == 0x08)
191 				r += 2;
192 			continue;
193 		}
194 		*w++ = *r;
195 	}
196 	return w-p;
197 }