access_vector_t string_to_av_perm(security_class_t tclass, const char *s)
{
struct discover_class_node *node;
security_class_t kclass = unmap_class(tclass);
node = get_class_cache_entry_value(kclass);
if (node != NULL) {
size_t i;
for (i=0; i<MAXVECTORS && node->perms[i] != NULL; i++)
if (strcmp(node->perms[i],s) == 0)
return map_perm(tclass, 1<<i);
}
errno = EINVAL;
return 0;
}
/*
* fchmod()
* Change mode of open file
*
* Our mapping of POSIXese to VSTa is as follows:
* "Other" affects the default protection granted
* "Group" affects all intermediate protections
* "User" affects the final, most specific match
*/
int
fchmod(int fd, int mode)
{
char *prot, buf[PERMLEN*8];
uchar prots[PERMLEN+1];
uint nprot, x;
/*
* Get current protections
*/
prot = rstat(__fd_port(fd), "acc");
if (prot == 0) {
return(__seterr(EINVAL));
}
/*
* Explode out to prots[]
*/
nprot = 0;
while ((nprot < (PERMLEN + 1)) && *prot && (*prot != '\n')) {
prots[nprot++] = atoi(prot);
prot = strchr(prot, '/');
if (!prot) {
break;
}
prot += 1;
}
/*
* Now mung up the protections based on a mapping of POSIX
* protection concepts.
*/
/*
* "User". Apllies to the most specific.
*/
map_perm(&prots[nprot-1], mode);
/*
* "Group". Applies to all of the rest except the most specific.
*/
mode <<= 3;
for (x = 1; x < (nprot-1); ++x) {
map_perm(&prots[x], mode);
}
/*
* "Other". Affects first (default) protection slot
*/
mode <<= 3;
map_perm(&prots[0], mode);
/*
* Build a "acc=X" to reflect potentially changed protection
*/
strcpy(buf, "acc=");
for (x = 0; x < nprot; ++x) {
sprintf(buf + strlen(buf), "%s%d",
x ? "/" : "",
prots[x]);
}
strcat(buf, "\n");
/*
* Send it back
*/
return(wstat(__fd_port(fd), buf));
}
