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minix/servers/vfs/select.c
Thomas Veerman 958b25be50 - Introduce support for sticky bit. 
- Revise VFS-FS protocol and update VFS/MFS/ISOFS accordingly.
- Clean up MFS by removing old, dead code (backwards compatibility is broken by
  the new VFS-FS protocol, anyway) and rewrite other parts. Also, make sure all
  functions have proper banners and prototypes.
- VFS should always provide a (syntactically) valid path to the FS; no need for
  the FS to do sanity checks when leaving/entering mount points.
- Fix several bugs in MFS:
  - Several path lookup bugs in MFS.
  - A link can be too big for the path buffer.
  - A mountpoint can become inaccessible when the creation of a new inode
    fails, because the inode already exists and is a mountpoint.
- Introduce support for supplemental groups.
- Add test 46 to test supplemental group functionality (and removed obsolete
  suppl. tests from test 2).
- Clean up VFS (not everything is done yet).
- ISOFS now opens device read-only. This makes the -r flag in the mount command
  unnecessary (but will still report to be mounted read-write).
- Introduce PipeFS. PipeFS is a new FS that handles all anonymous and
  named pipes. However, named pipes still reside on the (M)FS, as they are part
  of the file system on disk. To make this work VFS now has a concept of
  'mapped' inodes, which causes read, write, truncate and stat requests to be
  redirected to the mapped FS, and all other requests to the original FS.
2009-12-20 20:27:14 +00:00

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/* Implement entry point to select system call.
*
* The entry points into this file are
* do_select: perform the SELECT system call
* select_callback: notify select system of possible fd operation
* select_notified: low-level entry for device notifying select
* select_unsuspend_by_endpt: cancel a blocking select on exiting driver
*/
#define DEBUG_SELECT 0
#include "fs.h"
#include "select.h"
#include "file.h"
#include "vnode.h"
#include <sys/time.h>
#include <sys/select.h>
#include <minix/com.h>
#include <minix/u64.h>
#include <string.h>
/* max. number of simultaneously pending select() calls */
#define MAXSELECTS 25
#define FROM_PROC 0
#define TO_PROC 1
PRIVATE struct selectentry {
struct fproc *requestor; /* slot is free iff this is NULL */
int req_endpt;
fd_set readfds, writefds, errorfds;
fd_set ready_readfds, ready_writefds, ready_errorfds;
fd_set *vir_readfds, *vir_writefds, *vir_errorfds;
struct filp *filps[OPEN_MAX];
int type[OPEN_MAX];
int deferred; /* awaiting initial reply from driver */
int deferred_fd; /* fd awaiting initial reply from driver */
int nfds, nreadyfds;
char block;
clock_t expiry;
timer_t timer; /* if expiry > 0 */
} selecttab[MAXSELECTS];
FORWARD _PROTOTYPE(int copy_fdsets, (struct selectentry *se, int nfds,
int direction) );
FORWARD _PROTOTYPE(void filp_status, (struct filp *fp, int status) );
FORWARD _PROTOTYPE(void restart_proc, (int slot) );
FORWARD _PROTOTYPE(void ops2tab, (int ops, int fd, struct selectentry *e));
FORWARD _PROTOTYPE(int select_reevaluate, (struct filp *fp) );
FORWARD _PROTOTYPE(int select_request_file, (struct filp *f, int *ops,
int block) );
FORWARD _PROTOTYPE(int select_match_file, (struct filp *f) );
FORWARD _PROTOTYPE(int select_request_general, (struct filp *f, int *ops,
int block) );
FORWARD _PROTOTYPE(int select_request_asynch, (struct filp *f, int *ops,
int block) );
FORWARD _PROTOTYPE(int select_major_match, (int match_major,
struct filp *file) );
FORWARD _PROTOTYPE(void select_cancel_all, (struct selectentry *e) );
FORWARD _PROTOTYPE(void select_wakeup, (struct selectentry *e, int r) );
FORWARD _PROTOTYPE(void select_return, (struct selectentry *, int) );
FORWARD _PROTOTYPE(void sel_restart_dev, (void) );
FORWARD _PROTOTYPE(int tab2ops, (int fd, struct selectentry *e) );
FORWARD _PROTOTYPE(void wipe_select, (struct selectentry *s) );
PRIVATE struct fdtype {
int (*select_request)(struct filp *, int *ops, int block);
int (*select_match)(struct filp *);
int select_major;
} fdtypes[] = {
{ select_request_file, select_match_file, 0 },
{ select_request_general, NULL, TTY_MAJOR },
{ select_request_general, NULL, INET_MAJOR },
{ select_request_pipe, select_match_pipe, 0 },
{ select_request_asynch, NULL, LOG_MAJOR },
};
#define SEL_FDS (sizeof(fdtypes) / sizeof(fdtypes[0]))
/*===========================================================================*
* do_select *
*===========================================================================*/
PUBLIC int do_select(void)
{
/* Implement the select(nfds, readfds, writefds, errorfds, timeout) system
* call. First we copy the arguments and verify their sanity. Then we check
* whether there are file descriptors that satisfy the select call right of the
* bat. If so, or if there are no ready file descriptors but the process
* requested to return immediately, we return the result. Otherwise we set a
* timeout and wait for either the file descriptors to become ready or the
* timer to go off. If no timeout value was provided, we wait indefinitely. */
int r, nfds, do_timeout = 0, nonzero_timeout = 0, fd, s, fd_setsize;
struct timeval timeout;
struct selectentry *se;
nfds = m_in.SEL_NFDS;
/* Sane amount of file descriptors? */
if (nfds < 0 || nfds > OPEN_MAX) return(EINVAL);
fd_setsize = _FDSETWORDS(nfds) * _FDSETBITSPERWORD/8;
/* Find a slot to store this select request */
for (s = 0; s < MAXSELECTS; s++)
if (selecttab[s].requestor == NULL) /* Unused slot */
break;
if (s >= MAXSELECTS) return(ENOSPC);
se = &selecttab[s];
wipe_select(se); /* Clear results of previous usage.*/
se->req_endpt = who_e;
se->vir_readfds = (fd_set *) m_in.SEL_READFDS;
se->vir_writefds = (fd_set *) m_in.SEL_WRITEFDS;
se->vir_errorfds = (fd_set *) m_in.SEL_ERRORFDS;
/* Copy fdsets from the process */
if ((r = copy_fdsets(se, nfds, FROM_PROC)) != OK) return(r);
/* Did the process set a timeout value? If so, retrieve it. */
if (m_in.SEL_TIMEOUT != NULL) {
do_timeout = 1;
r = sys_vircopy(who_e, D, (vir_bytes) m_in.SEL_TIMEOUT, SELF, D,
(vir_bytes) &timeout, sizeof(timeout));
if (r != OK) return(r);
}
/* No nonsense in the timeval. */
if(do_timeout && (timeout.tv_sec < 0 || timeout.tv_usec < 0)) return(EINVAL);
/* If there is no timeout, we block forever. Otherwise, we block up to the
* specified time interval.
*/
if(!do_timeout) /* No timeout value set */
se->block = 1;
else if (do_timeout && (timeout.tv_sec > 0 || timeout.tv_usec > 0))
se->block = 1;
else /* timeout set as (0,0) - this effects a poll */
se->block = 0;
se->expiry = 0; /* no timer set (yet) */
/* Check all file descriptors in the set whether one is 'ready' now. */
for (fd = 0; fd < nfds; fd++) {
int ops, t, type = -1, r;
struct filp *filp;
if (!(ops = tab2ops(fd, se)))
continue; /* No operations set; nothing to do for this fd */
/* Get filp belonging to this fd */
filp = se->filps[fd] = get_filp(fd);
if (filp == NIL_FILP) {
if (err_code == EBADF) {
select_cancel_all(se);
return(EBADF);
}
/* File descriptor is 'ready' to return EIO */
printf("VFS do_select: EIO after driver failure\n");
ops2tab(SEL_RD|SEL_WR|SEL_ERR, fd, se);
continue;
}
/* Figure out what type of file we're dealing with */
for(t = 0; t < SEL_FDS; t++) {
if (fdtypes[t].select_match) {
if (fdtypes[t].select_match(filp)) {
type = t;
}
} else if (select_major_match(fdtypes[t].select_major, filp)) {
type = t;
}
}
if (type == -1) return(EBADF);
se->type[fd] = type;
/* Test filp for select operations if not already done so. e.g., files
* sharing a filp and both doing a select on that filp. */
if ((se->filps[fd]->filp_select_ops & ops) != ops) {
int wantops;
wantops = (se->filps[fd]->filp_select_ops |= ops);
r = fdtypes[type].select_request(filp, &wantops, se->block);
if (r != SEL_OK) {
if (r == SEL_DEFERRED) {
se->deferred = TRUE;
se->deferred_fd = 0;
continue;
}
/* Error or bogus return code; cancel select. */
select_cancel_all(se);
return(EINVAL);
}
/* The select request above might have turned on/off some
* operations because they were 'ready' or not meaningful.
* Either way, we might have a result and we need to store them
* in the select table entry. */
if (wantops & ops) ops2tab(wantops, fd, se);
}
se->nfds = fd+1;
se->filps[fd]->filp_selectors++;
}
if (se->nreadyfds > 0 || (!se->block && !se->deferred)) {
/* fd's were found that were ready to go right away, and/or
* we were instructed not to block at all. Must return
* immediately.
*/
r = copy_fdsets(se, se->nfds, TO_PROC);
select_cancel_all(se);
se->requestor = NULL;
if (r != OK) return(r);
else return(se->nreadyfds);
}
/* Convert timeval to ticks and set the timer. If it fails, undo
* all, return error.
*/
if (do_timeout) {
int ticks;
/* Open Group:
* "If the requested timeout interval requires a finer
* granularity than the implementation supports, the
* actual timeout interval shall be rounded up to the next
* supported value."
*/
#define USECPERSEC 1000000
while(timeout.tv_usec >= USECPERSEC) {
/* this is to avoid overflow with *system_hz below */
timeout.tv_usec -= USECPERSEC;
timeout.tv_sec++;
}
ticks = timeout.tv_sec * system_hz +
(timeout.tv_usec * system_hz + USECPERSEC-1) / USECPERSEC;
se->expiry = ticks;
fs_set_timer(&se->timer, ticks, select_timeout_check, s);
}
/* if we're blocking, the table entry is now valid. */
se->requestor = fp;
/* process now blocked */
suspend(FP_BLOCKED_ON_SELECT);
return(SUSPEND);
}
/*===========================================================================*
* select_request_file *
*===========================================================================*/
PRIVATE int select_request_file(struct filp *f, int *ops, int block)
{
/* output *ops is input *ops */
return(SEL_OK);
}
/*===========================================================================*
* select_match_file *
*===========================================================================*/
PRIVATE int select_match_file(struct filp *file)
{
return(file && file->filp_vno && (file->filp_vno->v_mode & I_REGULAR));
}
/*===========================================================================*
* select_request_general *
*===========================================================================*/
PRIVATE int select_request_general(struct filp *f, int *ops, int block)
{
int rops = *ops;
if (block) rops |= SEL_NOTIFY;
*ops = dev_io(VFS_DEV_SELECT, f->filp_vno->v_sdev, rops, NULL,
cvu64(0), 0, 0, FALSE);
if (*ops < 0)
return(SEL_ERR);
return(SEL_OK);
}
/*===========================================================================*
* select_request_asynch *
*===========================================================================*/
PRIVATE int select_request_asynch(struct filp *f, int *ops, int block)
{
int r, rops;
struct dmap *dp;
rops = *ops;
f->filp_select_flags |= FSF_UPDATE;
if (block) {
rops |= SEL_NOTIFY;
f->filp_select_flags |= FSF_BLOCK;
}
if (f->filp_select_flags & FSF_BUSY)
return(SEL_DEFERRED);
dp = &dmap[((f->filp_vno->v_sdev) >> MAJOR) & BYTE];
if (dp->dmap_sel_filp)
return(SEL_DEFERRED);
f->filp_select_flags &= ~FSF_UPDATE;
r = dev_io(VFS_DEV_SELECT, f->filp_vno->v_sdev, rops, NULL,
cvu64(0), 0, 0, FALSE);
if (r < 0 && r != SUSPEND)
return(SEL_ERR);
if (r != SUSPEND)
panic(__FILE__, "select_request_asynch: expected SUSPEND got", r);
f->filp_count++;
dp->dmap_sel_filp = f;
f->filp_select_flags |= FSF_BUSY;
return(SEL_DEFERRED);
}
/*===========================================================================*
* select_major_match *
*===========================================================================*/
PRIVATE int select_major_match(int match_major, struct filp *file)
{
int major;
if (!(file && file->filp_vno &&
(file->filp_vno->v_mode & I_TYPE) == I_CHAR_SPECIAL))
return(0);
major = (file->filp_vno->v_sdev >> MAJOR) & BYTE;
if (major == match_major) return 1;
return 0;
}
/*===========================================================================*
* tab2ops *
*===========================================================================*/
PRIVATE int tab2ops(int fd, struct selectentry *e)
{
int ops = 0;
if (FD_ISSET(fd, &e->readfds)) ops |= SEL_RD;
if (FD_ISSET(fd, &e->writefds)) ops |= SEL_WR;
if (FD_ISSET(fd, &e->errorfds)) ops |= SEL_ERR;
return(ops);
}
/*===========================================================================*
* ops2tab *
*===========================================================================*/
PRIVATE void ops2tab(int ops, int fd, struct selectentry *e)
{
if ((ops & SEL_RD) && e->vir_readfds && FD_ISSET(fd, &e->readfds) &&
!FD_ISSET(fd, &e->ready_readfds)) {
FD_SET(fd, &e->ready_readfds);
e->nreadyfds++;
}
if ((ops & SEL_WR) && e->vir_writefds && FD_ISSET(fd, &e->writefds) &&
!FD_ISSET(fd, &e->ready_writefds)) {
FD_SET(fd, &e->ready_writefds);
e->nreadyfds++;
}
if ((ops & SEL_ERR) && e->vir_errorfds && FD_ISSET(fd, &e->errorfds) &&
!FD_ISSET(fd, &e->ready_errorfds)) {
FD_SET(fd, &e->ready_errorfds);
e->nreadyfds++;
}
}
/*===========================================================================*
* copy_fdsets *
*===========================================================================*/
PRIVATE int copy_fdsets(struct selectentry *se, int nfds, int direction)
{
int fd_setsize, r;
endpoint_t src_e, dst_e;
fd_set *src_fds, *dst_fds;
if(nfds < 0 || nfds > OPEN_MAX)
panic(__FILE__, "select copy_fdsets: nfds wrong", nfds);
/* Only copy back as many bits as the user expects. */
fd_setsize = _FDSETWORDS(nfds) * _FDSETBITSPERWORD/8;
/* Set source and destination endpoints */
src_e = (direction == FROM_PROC) ? se->req_endpt : SELF;
dst_e = (direction == FROM_PROC) ? SELF : se->req_endpt;
/* read set */
src_fds = (direction == FROM_PROC) ? se->vir_readfds : &se->ready_readfds;
dst_fds = (direction == FROM_PROC) ? &se->readfds : se->vir_readfds;
if (se->vir_readfds) {
r = sys_vircopy(src_e, D, (vir_bytes) src_fds, dst_e, D,
(vir_bytes) dst_fds, fd_setsize);
if (r != OK) return(r);
}
/* write set */
src_fds = (direction == FROM_PROC) ? se->vir_writefds : &se->ready_writefds;
dst_fds = (direction == FROM_PROC) ? &se->writefds : se->vir_writefds;
if (se->vir_writefds) {
r = sys_vircopy(src_e, D, (vir_bytes) src_fds, dst_e, D,
(vir_bytes) dst_fds, fd_setsize);
if (r != OK) return(r);
}
/* error set */
src_fds = (direction == FROM_PROC) ? se->vir_errorfds : &se->ready_errorfds;
dst_fds = (direction == FROM_PROC) ? &se->errorfds : se->vir_errorfds;
if (se->vir_errorfds) {
r = sys_vircopy(src_e, D, (vir_bytes) src_fds, dst_e, D,
(vir_bytes) dst_fds, fd_setsize);
if (r != OK) return(r);
}
return(OK);
}
/*===========================================================================*
* select_cancel_all *
*===========================================================================*/
PRIVATE void select_cancel_all(struct selectentry *e)
{
int fd;
for(fd = 0; fd < e->nfds; fd++) {
struct filp *fp;
fp = e->filps[fd];
if (!fp) {
#if DEBUG_SELECT
printf("[ fd %d/%d NULL ] ", fd, e->nfds);
#endif
continue;
}
if (fp->filp_selectors < 1) {
#if DEBUG_SELECT
printf("select: %d selectors?!\n", fp->filp_selectors);
#endif
continue;
}
fp->filp_selectors--;
e->filps[fd] = NULL;
select_reevaluate(fp);
}
if (e->expiry > 0) {
#if DEBUG_SELECT
printf("cancelling timer %d\n", e - selecttab);
#endif
fs_cancel_timer(&e->timer);
e->expiry = 0;
}
return;
}
/*===========================================================================*
* select_wakeup *
*===========================================================================*/
PRIVATE void select_wakeup(struct selectentry *e, int r)
{
revive(e->req_endpt, r);
}
/*===========================================================================*
* select_reevaluate *
*===========================================================================*/
PRIVATE int select_reevaluate(struct filp *fp)
{
int s, remain_ops = 0, fd, type = -1;
if (!fp) {
printf("fs: select: reevalute NULL fp\n");
return 0;
}
for(s = 0; s < MAXSELECTS; s++) {
if (selecttab[s].requestor != NULL) continue;
for(fd = 0; fd < selecttab[s].nfds; fd++)
if (fp == selecttab[s].filps[fd]) {
remain_ops |= tab2ops(fd, &selecttab[s]);
type = selecttab[s].type[fd];
}
}
/* If there are any select()s open that want any operations on
* this fd that haven't been satisfied by this callback, then we're
* still in the market for it.
*/
fp->filp_select_ops = remain_ops;
#if DEBUG_SELECT
printf("remaining operations on fp are %d\n", fp->filp_select_ops);
#endif
return remain_ops;
}
/*===========================================================================*
* select_return *
*===========================================================================*/
PRIVATE void select_return(struct selectentry *se, int r)
{
select_cancel_all(se);
copy_fdsets(se, se->nfds, TO_PROC); /* FIXME, return error status */
select_wakeup(se, r ? r : se->nreadyfds);
se->requestor = NULL;
}
/*===========================================================================*
* select_callback *
*===========================================================================*/
PUBLIC int select_callback(struct filp *fp, int ops)
{
int s, fd, want_ops, type;
/* We are being notified that file pointer fp is available for
* operations 'ops'. We must re-register the select for
* operations that we are still interested in, if any.
*/
want_ops = 0;
type = -1;
for(s = 0; s < MAXSELECTS; s++) {
int wakehim = 0;
if (selecttab[s].requestor == NULL) continue;
for(fd = 0; fd < selecttab[s].nfds; fd++) {
if (!selecttab[s].filps[fd])
continue;
if (selecttab[s].filps[fd] == fp) {
int this_want_ops;
this_want_ops = tab2ops(fd, &selecttab[s]);
want_ops |= this_want_ops;
if (this_want_ops & ops) {
/* this select() has been satisfied. */
ops2tab(ops, fd, &selecttab[s]);
wakehim = 1;
}
type = selecttab[s].type[fd];
}
}
if (wakehim)
select_return(&selecttab[s], 0);
}
return 0;
}
/*===========================================================================*
* select_notified *
*===========================================================================*/
PUBLIC int select_notified(int major, int minor, int selected_ops)
{
int s, f, t;
#if DEBUG_SELECT
printf("select callback: %d, %d: %d\n", major, minor, selected_ops);
#endif
for(t = 0; t < SEL_FDS; t++)
if (!fdtypes[t].select_match && fdtypes[t].select_major == major)
break;
if (t >= SEL_FDS) {
#if DEBUG_SELECT
printf("select callback: no fdtype found for device %d\n", major);
#endif
return OK;
}
/* We have a select callback from major device no.
* d, which corresponds to our select type t.
*/
for(s = 0; s < MAXSELECTS; s++) {
int s_minor, ops;
if (selecttab[s].requestor == NULL) continue;
for(f = 0; f < selecttab[s].nfds; f++) {
if (!selecttab[s].filps[f] ||
!select_major_match(major, selecttab[s].filps[f]))
continue;
ops = tab2ops(f, &selecttab[s]);
s_minor =
(selecttab[s].filps[f]->filp_vno->v_sdev >> MINOR)
& BYTE;
if ((s_minor == minor) &&
(selected_ops & ops)) {
select_callback(selecttab[s].filps[f], (selected_ops & ops));
}
}
}
return OK;
}
/*===========================================================================*
* init_select *
*===========================================================================*/
PUBLIC void init_select(void)
{
int s;
for(s = 0; s < MAXSELECTS; s++)
fs_init_timer(&selecttab[s].timer);
}
/*===========================================================================*
* select_forget *
*===========================================================================*/
PUBLIC void select_forget(int proc_e)
{
/* something has happened (e.g. signal delivered that interrupts
* select()). totally forget about the select().
*/
int s;
for(s = 0; s < MAXSELECTS; s++) {
if (selecttab[s].requestor != NULL &&
selecttab[s].req_endpt == proc_e) {
break;
}
}
if (s >= MAXSELECTS) {
#if DEBUG_SELECT
printf("select: cancelled select() not found");
#endif
return;
}
select_cancel_all(&selecttab[s]);
selecttab[s].requestor = NULL;
return;
}
/*===========================================================================*
* select_timeout_check *
*===========================================================================*/
PUBLIC void select_timeout_check(timer_t *timer)
{
int s;
struct selectentry *se;
s = tmr_arg(timer)->ta_int;
if (s < 0 || s >= MAXSELECTS) {
#if DEBUG_SELECT
printf("select: bogus slot arg to watchdog %d\n", s);
#endif
return;
}
se = &selecttab[s]; /* Point to select table entry */
if (se->requestor == NULL) {
#if DEBUG_SELECT
printf("select: no requestor in watchdog\n");
#endif
return;
}
if (se->expiry <= 0) {
#if DEBUG_SELECT
printf("select: strange expiry value in watchdog\n", s);
#endif
return;
}
se->expiry = 0;
select_return(se, 0);
}
/*===========================================================================*
* select_unsuspend_by_endpt *
*===========================================================================*/
PUBLIC void select_unsuspend_by_endpt(endpoint_t proc_e)
{
int fd, s, maj;
for(s = 0; s < MAXSELECTS; s++) {
if (selecttab[s].requestor == NULL) continue;
for(fd = 0; fd < selecttab[s].nfds; fd++) {
if (selecttab[s].filps[fd] == NIL_FILP ||
selecttab[s].filps[fd]->filp_vno == NIL_VNODE) {
continue;
}
maj = (selecttab[s].filps[fd]->filp_vno->v_sdev >> MAJOR)&BYTE;
if (dmap_driver_match(proc_e, maj))
select_return(&selecttab[s], EAGAIN);
}
}
}
/*===========================================================================*
* select_reply1 *
*===========================================================================*/
PUBLIC void select_reply1()
{
int i, s, minor, status;
endpoint_t driver_e;
dev_t dev;
struct filp *fp;
struct dmap *dp;
struct vnode *vp;
driver_e= m_in.m_source;
minor= m_in.DEV_MINOR;
status= m_in.DEV_SEL_OPS;
/* Locate dmap entry */
for (i= 0, dp= dmap; i<NR_DEVICES; i++, dp++)
{
if (dp->dmap_driver == driver_e)
break;
}
if (i >= NR_DEVICES)
{
printf("select_reply1: proc %d is not a recoqnized driver\n",
driver_e);
return;
}
dev= (i << MAJOR) | (minor & BYTE);
fp= dp->dmap_sel_filp;
if (!fp)
{
printf("select_reply1: strange, no dmap_sel_filp\n");
return;
}
if (!(fp->filp_select_flags & FSF_BUSY))
panic(__FILE__, "select_reply1: strange, not FSF_BUSY", NO_NUM);
vp= fp->filp_vno;
if (!vp)
panic(__FILE__, "select_reply1: FSF_BUSY but no vp", NO_NUM);
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL)
{
panic(__FILE__, "select_reply1: FSF_BUSY but not char special",
NO_NUM);
}
if (vp->v_sdev != dev)
{
printf("select_reply1: strange, reply from wrong dev\n");
return;
}
dp->dmap_sel_filp= NULL;
fp->filp_select_flags &= ~FSF_BUSY;
if (!(fp->filp_select_flags & (FSF_UPDATE|FSF_BLOCK)))
fp->filp_select_ops= 0;
if (status != 0)
{
if (status > 0)
{
/* Clear the replied bits from the request mask unless
* FSF_UPDATE is set.
*/
if (!(fp->filp_select_flags & FSF_UPDATE))
fp->filp_select_ops &= ~status;
}
filp_status(fp, status);
}
if (fp->filp_count > 1)
fp->filp_count--;
else
{
if (fp->filp_count != 1)
{
panic(__FILE__, "select_reply1: bad filp_count",
fp->filp_count);
}
close_filp(fp);
}
sel_restart_dev();
}
/*===========================================================================*
* select_reply2 *
*===========================================================================*/
PUBLIC void select_reply2()
{
int i, s, minor, status;
endpoint_t driver_e;
dev_t dev;
struct filp *fp;
struct dmap *dp;
struct vnode *vp;
driver_e= m_in.m_source;
minor= m_in.DEV_MINOR;
status= m_in.DEV_SEL_OPS;
/* Locate dmap entry */
for (i= 0, dp= dmap; i<NR_DEVICES; i++, dp++)
{
if (dp->dmap_driver == driver_e)
break;
}
if (i >= NR_DEVICES)
{
printf("select_reply2: proc %d is not a recognized driver\n",
driver_e);
return;
}
dev= (i << MAJOR) | (minor & BYTE);
/* Find filedescriptors for this device */
for (s= 0; s<MAXSELECTS; s++)
{
if (selecttab[s].requestor == NULL)
continue; /* empty slot */
for (i= 0; i<OPEN_MAX; i++)
{
fp= selecttab[s].filps[i];
if (!fp)
continue;
vp= fp->filp_vno;
if (!vp)
continue;
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL)
continue;
if (vp->v_sdev != dev)
continue;
if (status < 0)
{
printf("select_reply2: should handle error\n");
}
else
{
/* Clear the replied bits from the request
* mask unless FSF_UPDATE is set.
*/
if (!(fp->filp_select_flags & FSF_UPDATE))
fp->filp_select_ops &= ~status;
ops2tab(status, i, &selecttab[s]);
}
}
if (selecttab[s].nreadyfds > 0)
restart_proc(s);
}
}
PRIVATE void sel_restart_dev()
{
int i, s;
struct filp *fp;
struct vnode *vp;
struct dmap *dp;
/* Locate filps that can be restarted */
for (s= 0; s<MAXSELECTS; s++)
{
if (selecttab[s].requestor == NULL)
continue; /* empty slot */
if (!selecttab[s].deferred)
continue; /* process is not waiting for an
* initial reply.
*/
for (i= 0; i<OPEN_MAX; i++)
{
fp= selecttab[s].filps[i];
if (!fp)
continue;
if (fp->filp_select_flags & FSF_BUSY)
continue;
if (!(fp->filp_select_flags & FSF_UPDATE))
continue;
vp= fp->filp_vno;
if (!vp)
{
panic(__FILE__,
"sel_restart_dev: FSF_UPDATE but no vp",
NO_NUM);
}
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL)
{
panic(__FILE__,
"sel_restart_dev: FSF_UPDATE but not char special",
NO_NUM);
}
dp = &dmap[((vp->v_sdev) >> MAJOR) & BYTE];
if (dp->dmap_sel_filp)
continue;
printf(
"sel_restart_dev: should consider fd %d in slot %d\n",
i, s);
}
}
}
PRIVATE void filp_status(fp, status)
struct filp *fp;
int status;
{
int i, s;
/* Locate processes that need to know about this result */
for (s= 0; s<MAXSELECTS; s++)
{
if (selecttab[s].requestor == NULL) continue; /* empty slot */
for (i= 0; i<OPEN_MAX; i++)
{
if (selecttab[s].filps[i] != fp)
continue;
if (status < 0)
{
printf("filp_status: should handle error\n");
}
else
ops2tab(status, i, &selecttab[s]);
restart_proc(s);
}
}
}
PRIVATE void restart_proc(slot)
int slot;
{
int fd;
struct selectentry *se;
struct filp *fp;
se= &selecttab[slot];
if (se->deferred)
{
for (fd= se->deferred_fd; fd < OPEN_MAX; fd++)
{
fp= se->filps[fd];
if (!fp)
continue;
if (fp->filp_select_flags & (FSF_UPDATE|FSF_BUSY))
break;
}
if (fd < OPEN_MAX)
{
se->deferred_fd= fd;
return;
}
se->deferred= FALSE;
}
if (se->nreadyfds > 0 || !se->block) {
copy_fdsets(se, se->nfds, TO_PROC); /* FIXME, return error */
select_wakeup(se, se->nreadyfds);
se->requestor = NULL;
}
}
/*===========================================================================*
* wipe_select *
*===========================================================================*/
PRIVATE void wipe_select(struct selectentry *se)
{
se->deferred = FALSE;
se->nfds = 0;
se->nreadyfds = 0;
/* memset(se->filps, 0, OPEN_MAX * sizeof(struct filp *)); */
memset(se->filps, 0, sizeof(se->filps));
FD_ZERO(&se->readfds);
FD_ZERO(&se->writefds);
FD_ZERO(&se->errorfds);
FD_ZERO(&se->ready_readfds);
FD_ZERO(&se->ready_writefds);
FD_ZERO(&se->ready_errorfds);
}
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