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glibc  2.9
Functions
setuid.c File Reference
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <hurd.h>
#include <hurd/id.h>
#include <string.h>

Go to the source code of this file.

Functions

int __setuid (uid_t uid)

Function Documentation

int __setuid ( uid_t  uid)

Definition at line 31 of file setuid.c.

{
  auth_t newauth;
  error_t err;

  HURD_CRITICAL_BEGIN;
  __mutex_lock (&_hurd_id.lock);
  err = _hurd_check_ids ();

  if (!err)
    {
      /* Make a new auth handle which has UID as the real uid,
        and as the first element in the list of effective uids.  */

      uid_t *newgen, *newaux, auxbuf[2];
      size_t ngen, naux;

      newaux = _hurd_id.aux.uids;
      naux = _hurd_id.aux.nuids;
      if (_hurd_id.gen.nuids == 0)
       {
         /* No effective uids now.  The new set will be just UID.  */
         newgen = &uid;
         ngen = 1;
       }
      else if (_hurd_id.gen.uids[0] == 0)
       {
         /* We are root; set the effective, real, and saved to UID.  */
         _hurd_id.gen.uids[0] = uid;
         _hurd_id.valid = 0;
         newgen = _hurd_id.gen.uids;
         ngen = _hurd_id.gen.nuids;
         if (_hurd_id.aux.nuids < 2)
           {
             newaux = auxbuf;
             naux = 2;
           }
         newaux[0] = newaux[1] = uid;
       }
      else
       {
         /* We are not root; just change the effective UID.  */
         /* XXX that implies an unprivileged setuid(0) will give
            the caller root, no questions asked! */
         _hurd_id.gen.uids[0] = uid;
         _hurd_id.valid = 0;
         newgen = _hurd_id.gen.uids;
         ngen = _hurd_id.gen.nuids;
       }

      err = __USEPORT (AUTH, __auth_makeauth
                     (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,
                     newgen, ngen, newaux, naux,
                     _hurd_id.gen.gids, _hurd_id.gen.ngids,
                     _hurd_id.aux.gids, _hurd_id.aux.ngids,
                     &newauth));
    }
  __mutex_unlock (&_hurd_id.lock);
  HURD_CRITICAL_END;

  if (err)
    return __hurd_fail (err);

  /* Install the new handle and reauthenticate everything.  */
  err = __setauth (newauth);
  __mach_port_deallocate (__mach_task_self (), newauth);
  return err;
}

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