include/net/scm.h

   1 #ifndef __LINUX_NET_SCM_H
   2 #define __LINUX_NET_SCM_H
   3
   4 #include <linux/limits.h>
   5 #include <linux/net.h>
   6
   7 /* Well, we should have at least one descriptor open
   8  * to accept passed FDs 8)
   9  */
  10 #define SCM_MAX_FD      (OPEN_MAX-1)
  11
  12 struct scm_fp_list
  13 {
  14         int             count;
  15         struct file     *fp[SCM_MAX_FD];
  16 };
  17
  18 struct scm_cookie
  19 {
  20         struct ucred            creds;          /* Skb credentials      */
  21         struct scm_fp_list      *fp;            /* Passed files         */
  22         unsigned long           seq;            /* Connection seqno     */
  23 };
  24
  25 extern void scm_detach_fds(struct msghdr *msg, struct scm_cookie *scm);
  26 extern void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm);
  27 extern int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *scm);
  28 extern void __scm_destroy(struct scm_cookie *scm);
  29 extern struct scm_fp_list * scm_fp_dup(struct scm_fp_list *fpl);
  30
  31 static __inline__ void scm_destroy(struct scm_cookie *scm)
  32 {
  33         if (scm && scm->fp)
  34                 __scm_destroy(scm);
  35 }
  36
  37 static __inline__ int scm_send(struct socket *sock, struct msghdr *msg,
  38                                struct scm_cookie *scm)
  39 {
  40         struct task_struct *p = current;
  41         scm->creds.uid = p->uid;
  42         scm->creds.gid = p->gid;
  43         scm->creds.pid = p->tgid;
  44         scm->fp = NULL;
  45         scm->seq = 0;
  46         if (msg->msg_controllen <= 0)
  47                 return 0;
  48         return __scm_send(sock, msg, scm);
  49 }
  50
  51 static __inline__ void scm_recv(struct socket *sock, struct msghdr *msg,
  52                                 struct scm_cookie *scm, int flags)
  53 {
  54         if (!msg->msg_control)
  55         {
  56                 if (test_bit(SOCK_PASSCRED, &sock->flags) || scm->fp)
  57                         msg->msg_flags |= MSG_CTRUNC;
  58                 scm_destroy(scm);
  59                 return;
  60         }
  61
  62         if (test_bit(SOCK_PASSCRED, &sock->flags))
  63                 put_cmsg(msg, SOL_SOCKET, SCM_CREDENTIALS, sizeof(scm->creds), &scm->creds);
  64
  65         if (!scm->fp)
  66                 return;
  67
  68         scm_detach_fds(msg, scm);
  69 }
  70
  71
  72 #endif /* __LINUX_NET_SCM_H */
  73