1 #include <u.h>
2 #include <libc.h>
3 
4 /*
5  * /adm/users is
6  *	id:user/group:head member:other members
7  *
8  * /etc/{passwd,group}
9  *	name:x:nn:other stuff
10  */
11 
12 static int isnumber(char *s);
13 
14 sniff(Biobuf *b)
15 {
16 	read first line of file into p;
17 
18 	nf = getfields(p, f, nelem(f), ":");
19 	if(nf < 4)
20 		return nil;
21 
22 	if(isnumber(f[0]) && !isnumber(f[2]))
23 		return _plan9;
24 
25 	if(!isnumber(f[0]) && isnumber(f[2]))
26 		return _unix;
27 
28 	return nil;
29 }
30 
31 
32 int
33 isnumber(char *s)
34 {
35 	char *q;
36 
37 	strtol(s, &q, 10);
38 	return *q == '\0';
39 }
40 
41 /* EOF */