minix/kernel/system/do_privctl.c
2005-08-05 09:41:15 +00:00

87 lines
3 KiB
C

/* The system call implemented in this file:
* m_type: SYS_PRIVCTL
*
* The parameters for this system call are:
* m1_i1: PR_PROC_NR (process number of caller)
*
* Changes:
* Jul 13, 2005 created to dynamically start services (Jorrit N. Herder)
*/
#include "../system.h"
#include "../ipc.h"
#include <signal.h>
#if USE_PRIVCTL
#define FILLED_MASK (~0)
/*===========================================================================*
* do_privctl *
*===========================================================================*/
PUBLIC int do_privctl(m_ptr)
message *m_ptr; /* pointer to request message */
{
/* Handle sys_privctl(). Update a process' privileges. If the process is not
* yet a system process, make sure it gets its own privilege structure.
*/
register struct proc *caller_ptr;
register struct proc *rp;
register struct priv *sp;
int proc_nr;
int priv_id;
int old_flags;
int i;
/* Check whether caller is allowed to make this call. Privileged proceses
* can only update the privileges of processes that are inhibited from
* running by the NO_PRIV flag. This flag is set when a privileged process
* forks.
*/
caller_ptr = proc_addr(m_ptr->m_source);
if (! (priv(caller_ptr)->s_flags & SYS_PROC)) return(EPERM);
proc_nr = m_ptr->PR_PROC_NR;
if (! isokprocn(proc_nr)) return(EINVAL);
rp = proc_addr(proc_nr);
if (! (rp->p_rts_flags & NO_PRIV)) return(EPERM);
/* Make sure this process has its own privileges structure. This may fail,
* since there are only a limited number of system processes. Then copy the
* privileges from the caller and restore some defaults.
*/
if ((i=get_priv(rp, SYS_PROC)) != OK) return(i);
priv_id = priv(rp)->s_id; /* backup privilege id */
*priv(rp) = *priv(caller_ptr); /* copy from caller */
priv(rp)->s_id = priv_id; /* restore privilege id */
priv(rp)->s_proc_nr = proc_nr; /* reassociate process nr */
for (i=0; i< BITMAP_CHUNKS(NR_SYS_PROCS); i++) /* remove pending: */
priv(rp)->s_notify_pending.chunk[i] = 0; /* - notifications */
priv(rp)->s_int_pending = 0; /* - interrupts */
sigemptyset(&priv(rp)->s_sig_pending); /* - signals */
/* Now update the process' privileges as requested. */
rp->p_priv->s_trap_mask = FILLED_MASK;
for (i=0; i<BITMAP_CHUNKS(NR_SYS_PROCS); i++) {
rp->p_priv->s_ipc_to.chunk[i] = FILLED_MASK;
}
unset_sys_bit(rp->p_priv->s_ipc_to, USER_PRIV_ID);
/* All process that this process can send to must be able to reply.
* Therefore, their send masks should be updated as well.
*/
for (i=0; i<NR_SYS_PROCS; i++) {
if (get_sys_bit(rp->p_priv->s_ipc_to, i)) {
set_sys_bit(priv_addr(i)->s_ipc_to, priv_id(rp));
}
}
/* Done. Privileges have been set. Allow process to run again. */
old_flags = rp->p_rts_flags; /* save value of the flags */
rp->p_rts_flags &= ~NO_PRIV;
if (old_flags != 0 && rp->p_rts_flags == 0) lock_ready(rp);
return(OK);
}
#endif /* USE_PRIVCTL */