minix/kernel/system/do_exit.c
Ben Gras 41e9fedf87 Mostly bugfixes of bugs triggered by the test set.
bugfixes:
 SYSTEM:
 . removed
        rc->p_priv->s_flags = 0;
   for the priv struct shared by all user processes in get_priv(). this
   should only be done once. doing a SYS_PRIV_USER in sys_privctl()
   caused the flags of all user processes to be reset, so they were no
   longer PREEMPTIBLE. this happened when RS executed a policy script.
   (this broke test1 in the test set)

 VFS/MFS:
 . chown can change the mode of a file, and chmod arguments are only
   part of the full file mode so the full filemode is slightly magic.
   changed these calls so that the final modes are returned to VFS, so
   that the vnode can be kept up-to-date.
   (this broke test11 in the test set)

 MFS:
 . lookup() checked for sizeof(string) instead of sizeof(user_path),
   truncating long path names
   (caught by test 23)
 . truncate functions neglected to update ctime
   (this broke test16)

 VFS:
 . corner case of an empty filename lookup caused fields of a request
   not to be filled in in the lookup functions, not making it clear
   that the lookup had failed, causing messages to garbage processes,
   causing strange failures.
   (caught by test 30)
 . trust v_size in vnode when doing reads or writes on non-special
   files, truncating i/o where necessary; this is necessary for pipes,
   as MFS can't tell when a pipe has been truncated without it being
   told explicitly each time.
   when the last reader/writer on a pipe closes, tell FS about
   the new size using truncate_vn().
   (this broke test 25, among others)
 . permission check for chdir() had disappeared; added a
   forbidden() call
   (caught by test 23)

new code, shouldn't change anything:
 . introduced RTS_SET, RTS_UNSET, and RTS_ISSET macro's, and their
   LOCK variants. These macros set and clear the p_rts_flags field,
   causing a lot of duplicated logic like

       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_enqueue(rp);

   to change into the simpler

       RTS_LOCK_UNSET(rp, NO_PRIV);

   so the macros take care of calling dequeue() and enqueue() (or lock_*()),
   as the case may be). This makes the code a bit more readable and a
   bit less fragile.
 . removed return code from do_clocktick in CLOCK as it currently
   never replies
 . removed some debug code from VFS
 . fixed grant debug message in device.c
 
preemptive checks, tests, changes:
 . added return code checks of receive() to SYSTEM and CLOCK
 . O_TRUNC should never arrive at MFS (added sanity check and removed
   O_TRUNC code)
 . user_path declared with PATH_MAX+1 to let it be null-terminated
 . checks in MFS to see if strings passed by VFS are null-terminated
 
 IS:
 . static irq name table thrown out
2007-02-01 17:50:02 +00:00

92 lines
3 KiB
C

/* The kernel call implemented in this file:
* m_type: SYS_EXIT
*
* The parameters for this kernel call are:
* m1_i1: PR_ENDPT (slot number of exiting process)
*/
#include "../system.h"
#include <minix/endpoint.h>
#if USE_EXIT
FORWARD _PROTOTYPE( void clear_proc, (register struct proc *rc));
/*===========================================================================*
* do_exit *
*===========================================================================*/
PUBLIC int do_exit(m_ptr)
message *m_ptr; /* pointer to request message */
{
/* Handle sys_exit. A user process has exited or a system process requests
* to exit. Only the PM can request other process slots to be cleared.
* The routine to clean up a process table slot cancels outstanding timers,
* possibly removes the process from the message queues, and resets certain
* process table fields to the default values.
*/
int exit_e;
/* Determine what process exited. User processes are handled here. */
if (PM_PROC_NR == who_p) {
if (m_ptr->PR_ENDPT != SELF) { /* PM tries to exit self */
if(!isokendpt(m_ptr->PR_ENDPT, &exit_e)) /* get exiting process */
return EINVAL;
clear_proc(proc_addr(exit_e)); /* exit a user process */
return(OK); /* report back to PM */
}
}
/* The PM or some other system process requested to be exited. */
clear_proc(proc_addr(who_p));
return(EDONTREPLY);
}
/*===========================================================================*
* clear_proc *
*===========================================================================*/
PRIVATE void clear_proc(rc)
register struct proc *rc; /* slot of process to clean up */
{
register struct proc *rp; /* iterate over process table */
register struct proc **xpp; /* iterate over caller queue */
int i;
int sys_id;
/* Don't clear if already cleared. */
if(isemptyp(rc)) return;
/* Remove the process' ability to send and receive messages */
clear_endpoint(rc);
/* Turn off any alarm timers at the clock. */
reset_timer(&priv(rc)->s_alarm_timer);
/* Make sure that the exiting process is no longer scheduled,
* and mark slot as FREE.
*/
RTS_LOCK_SETFLAGS(rc, SLOT_FREE);
/* Check the table with IRQ hooks to see if hooks should be released. */
for (i=0; i < NR_IRQ_HOOKS; i++) {
int proc;
if (rc->p_endpoint == irq_hooks[i].proc_nr_e) {
rm_irq_handler(&irq_hooks[i]); /* remove interrupt handler */
irq_hooks[i].proc_nr_e = NONE; /* mark hook as free */
}
}
/* Release the process table slot. If this is a system process, also
* release its privilege structure. Further cleanup is not needed at
* this point. All important fields are reinitialized when the
* slots are assigned to another, new process.
*/
if (priv(rc)->s_flags & SYS_PROC) priv(rc)->s_proc_nr = NONE;
/* Clean up virtual memory */
if (rc->p_misc_flags & MF_VM)
vm_map_default(rc);
}
#endif /* USE_EXIT */