minix/servers/ipc/utility.c

   1 #include "inc.h"
   2
   3 int
   4 check_perm(struct ipc_perm * req, endpoint_t who, int mode)
   5 {
   6         int req_mode;
   7         uid_t uid;
   8         gid_t gid;
   9
  10         uid = getnuid(who);
  11         gid = getngid(who);
  12         mode &= 0700;
  13
  14         /* Root is allowed to do anything. */
  15         if (uid == 0)
  16                 return TRUE;
  17
  18         if (uid == req->uid || uid == req->cuid) {
  19                 /* Same user. */
  20                 req_mode = req->mode & 0700;
  21         } else if (gid == req->gid || gid == req->cgid) {
  22                 /* Same group. */
  23                 req_mode = req->mode & 0070;
  24                 mode >>= 3;
  25         } else {
  26                 /* Other user and group. */
  27                 req_mode = req->mode & 0007;
  28                 mode >>= 6;
  29         }
  30
  31         return (mode && ((mode & req_mode) == mode));
  32 }
  33
  34 /*
  35  * Copy over an ipc_perm structure to an ipc_perm_sysctl structure.
  36  */
  37 void
  38 prepare_mib_perm(struct ipc_perm_sysctl * perms, const struct ipc_perm * perm)
  39 {
  40
  41         memset(perms, 0, sizeof(*perms));
  42         perms->_key = perm->_key;
  43         perms->uid = perm->uid;
  44         perms->gid = perm->gid;
  45         perms->cuid = perm->cuid;
  46         perms->cgid = perm->cgid;
  47         perms->mode = perm->mode;
  48         perms->_seq = perm->_seq;
  49 }