1 #include <u.h>
2 #include <libc.h>
3 
4 /*
5  * Search $PATH for an executable with the given name.
6  * Like in rc, mid-name slashes do not disable search.
7  * Should probably handle escaped colons,
8  * but I don't know what the syntax is.
9  */
10 char*
11 searchpath(char *name)
12 {
13 	char *path, *p, *next;
14 	char *s, *ss;
15 	int ns, l;
16 
17 	s = nil;
18 	ns = 0;
19 	if((name[0] == '.' && name[1] == '/')
20 	|| (name[0] == '.' && name[1] == '.' && name[2] == '/')
21 	|| (name[0] == '/')){
22 		if(access(name, AEXEC) >= 0)
23 			return strdup(name);
24 		return nil;
25 	}
26 
27 	path = getenv("PATH");
28 	for(p=path; p && *p; p=next){
29 		if((next = strchr(p, ':')) != nil)
30 			*next++ = 0;
31 		if(*p == 0){
32 			if(access(name, AEXEC) >= 0){
33 				free(s);
34 				free(path);
35 				return strdup(name);
36 			}
37 		}else{
38 			l = strlen(p)+1+strlen(name)+1;
39 			if(l > ns){
40 				ss = realloc(s, l);
41 				if(ss == nil){
42 					free(s);
43 					free(path);
44 					return nil;
45 				}
46 				s = ss;
47 				ns = l;
48 			}
49 			strcpy(s, p);
50 			strcat(s, "/");
51 			strcat(s, name);
52 			if(access(s, AEXEC) >= 0){
53 				free(path);
54 				return s;
55 			}
56 		}
57 	}
58 	free(s);
59 	free(path);
60 	return nil;
61 }