1 #include <u.h>
2 #include <libc.h>
3 #include <ctype.h>
4 
5 static int
6 isme(char *uid)
7 {
8 	int n;
9 	char *p;
10 
11 	n = strtol(uid, &p, 10);
12 	if(*p == 0 && p > uid)
13 		return n == getuid();
14 	return strcmp(getuser(), uid) == 0;
15 }
16 /*
17  * Absent other hints, it works reasonably well to use
18  * the X11 display name as the name space identifier.
19  * This is how sam's B has worked since the early days.
20  * Since most programs using name spaces are also using X,
21  * this still seems reasonable.  Terminal-only sessions
22  * can set $NAMESPACE.
23  */
24 static char*
25 nsfromdisplay(void)
26 {
27 	int fd;
28 	Dir *d;
29 	char *disp, *p;
30 
31 	if((disp = getenv("DISPLAY")) == nil){
32 #ifdef __APPLE__
33 		// Might be running native GUI on OS X.
34 		disp = strdup(":0.0");
35 		if(disp == nil)
36 			return nil;
37 #else
38 		werrstr("$DISPLAY not set");
39 		return nil;
40 #endif
41 	}
42 
43 	/* canonicalize: xxx:0.0 => xxx:0 */
44 	p = strrchr(disp, ':');
45 	if(p){
46 		p++;
47 		while(isdigit((uchar)*p))
48 			p++;
49 		if(strcmp(p, ".0") == 0)
50 			*p = 0;
51 	}
52 
53 	/* turn /tmp/launch/:0 into _tmp_launch_:0 (OS X 10.5) */
54 	for(p=disp; *p; p++)
55 		if(*p == '/')
56 			*p = '_';
57 
58 	p = smprint("/tmp/ns.%s.%s", getuser(), disp);
59 	free(disp);
60 	if(p == nil){
61 		werrstr("out of memory");
62 		return p;
63 	}
64 	if((fd=create(p, OREAD, DMDIR|0700)) >= 0){
65 		close(fd);
66 		return p;
67 	}
68 	if((d = dirstat(p)) == nil){
69 		free(d);
70 		werrstr("stat %s: %r", p);
71 		free(p);
72 		return nil;
73 	}
74 	if((d->mode&0777) != 0700 || !isme(d->uid)){
75 		werrstr("bad name space dir %s", p);
76 		free(p);
77 		free(d);
78 		return nil;
79 	}
80 	free(d);
81 	return p;
82 }
83 
84 char*
85 getns(void)
86 {
87 	char *ns;
88 
89 	ns = getenv("NAMESPACE");
90 	if(ns == nil)
91 		ns = nsfromdisplay();
92 	if(ns == nil){
93 		werrstr("$NAMESPACE not set, %r");
94 		return nil;
95 	}
96 	return ns;
97 }