1 #include <u.h>
2 #include <libc.h>
3 #include <ctype.h>
4 
5 /*
6  * Absent other hints, it works reasonably well to use
7  * the X11 display name as the name space identifier.
8  * This is how sam's B has worked since the early days.
9  * Since most programs using name spaces are also using X,
10  * this still seems reasonable.  Terminal-only sessions
11  * can set $NAMESPACE.
12  */
13 static char*
14 nsfromdisplay(void)
15 {
16 	int fd;
17 	Dir *d;
18 	char *disp, *p;
19 
20 	if((disp = getenv("DISPLAY")) == nil){
21 		werrstr("$DISPLAY not set");
22 		return nil;
23 	}
24 
25 	/* canonicalize: xxx:0.0 => xxx:0 */
26 	p = strrchr(disp, ':');
27 	if(p){
28 		p++;
29 		while(isdigit((uchar)*p))
30 			p++;
31 		if(strcmp(p, ".0") == 0)
32 			*p = 0;
33 	}
34 
35 	p = smprint("/tmp/ns.%s.%s", getuser(), disp);
36 	free(disp);
37 	if(p == nil){
38 		werrstr("out of memory");
39 		return p;
40 	}
41 	if((fd=create(p, OREAD, DMDIR|0700)) >= 0){
42 		close(fd);
43 		return p;
44 	}
45 	if((d = dirstat(p)) == nil){
46 		free(d);
47 		werrstr("stat %s: %r", p);
48 		free(p);
49 		return nil;
50 	}
51 	if((d->mode&0777) != 0700 || strcmp(d->uid, getuser()) != 0){
52 		werrstr("bad name space dir %s", p);
53 		free(p);
54 		free(d);
55 		return nil;
56 	}
57 	free(d);
58 	return p;
59 }
60 
61 char*
62 getns(void)
63 {
64 	char *ns;
65 
66 	ns = getenv("NAMESPACE");
67 	if(ns == nil)
68 		ns = nsfromdisplay();
69 	if(ns == nil){
70 		werrstr("$NAMESPACE not set, %r");
71 		return nil;
72 	}
73 	return ns;
74 }