xref: /csrg-svn/lib/libc/gen/devname.c (revision 40258)
1*40258Smarc #include <sys/types.h>
2*40258Smarc #include <sys/dir.h>
3*40258Smarc #include <sys/stat.h>
4*40258Smarc #include "pathnames.h"
5*40258Smarc #include <stdio.h>
6*40258Smarc 
7*40258Smarc struct devs {
8*40258Smarc 	dev_t	dev;
9*40258Smarc 	char	name[MAXNAMLEN+1];
10*40258Smarc 	struct	devs *next;
11*40258Smarc };
12*40258Smarc 
13*40258Smarc struct devs *devhash[minor(~0)];
14*40258Smarc 
15*40258Smarc int devinit;
16*40258Smarc 
17*40258Smarc /* TODO - use a database file stored in /dev, - just check mod time on /dev
18*40258Smarc 	hide data structures
19*40258Smarc */
20*40258Smarc 
21*40258Smarc char *
22*40258Smarc devname(dev)
23*40258Smarc 	dev_t dev;
24*40258Smarc {
25*40258Smarc 	struct devs *devp;
26*40258Smarc 
27*40258Smarc 	if (devinit == 0) {
28*40258Smarc 		DIR *dp = opendir(_PATH_DEV);
29*40258Smarc 		struct direct *entry;
30*40258Smarc 		struct stat sb;
31*40258Smarc 		struct devs *devpp;
32*40258Smarc 
33*40258Smarc 		/* XXX XXX - can't chdir as a library routine (add flag?) */
34*40258Smarc 		if (dp == NULL || chdir(_PATH_DEV) == -1)
35*40258Smarc 			return (NULL);
36*40258Smarc 		while ((entry = readdir(dp)) != NULL) {
37*40258Smarc 			if (stat(entry->d_name, &sb) == -1)
38*40258Smarc 				continue;
39*40258Smarc 			if ((sb.st_mode&S_IFMT) != S_IFCHR)
40*40258Smarc 				continue;
41*40258Smarc 			devp = (struct devs *)malloc(sizeof (struct devs));
42*40258Smarc 			if (devp == NULL)
43*40258Smarc 				return (NULL);
44*40258Smarc 			devp->dev = sb.st_rdev;
45*40258Smarc 			strcpy(devp->name, entry->d_name);
46*40258Smarc 			devp->next = NULL;
47*40258Smarc 			if ((devpp = devhash[minor(sb.st_rdev)]) == NULL)
48*40258Smarc 				devhash[minor(sb.st_rdev)] = devp;
49*40258Smarc 			else {
50*40258Smarc 				for (;devpp->next != NULL; devpp = devpp->next)
51*40258Smarc 					;
52*40258Smarc 				devpp->next = devp;
53*40258Smarc 			}
54*40258Smarc 		}
55*40258Smarc 		devinit = 1; 	/* XXX - should have way to invalidate cache ?*/
56*40258Smarc 	}
57*40258Smarc 	for (devp = devhash[minor(dev)]; devp != NULL; devp = devp->next)
58*40258Smarc 		if (dev == devp->dev)
59*40258Smarc 			return(devp->name);
60*40258Smarc 
61*40258Smarc 	return (NULL);
62*40258Smarc }
63*40258Smarc 
64*40258Smarc #ifdef TEST
65*40258Smarc main() {
66*40258Smarc 	printf(" %s \n", devname(0));
67*40258Smarc }
68*40258Smarc #endif
69