- select_request_async() returns no ops by default - wantops in do_select() always set correctly, do_select() does not need a special case for SUSPEND (and ugly code)
1060 lines
32 KiB
C
1060 lines
32 KiB
C
/* Implement entry point to select system call.
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*
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* The entry points into this file are
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* do_select: perform the SELECT system call
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* select_callback: notify select system of possible fd operation
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* select_unsuspend_by_endpt: cancel a blocking select on exiting driver
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*/
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#include "fs.h"
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#include <sys/time.h>
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#include <sys/select.h>
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#include <minix/com.h>
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#include <minix/u64.h>
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#include <string.h>
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#include <assert.h>
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#include "file.h"
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#include "fproc.h"
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#include "dmap.h"
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#include "vnode.h"
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/* max. number of simultaneously pending select() calls */
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#define MAXSELECTS 25
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#define FROM_PROC 0
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#define TO_PROC 1
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PRIVATE struct selectentry {
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struct fproc *requestor; /* slot is free iff this is NULL */
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endpoint_t req_endpt;
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fd_set readfds, writefds, errorfds;
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fd_set ready_readfds, ready_writefds, ready_errorfds;
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fd_set *vir_readfds, *vir_writefds, *vir_errorfds;
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struct filp *filps[OPEN_MAX];
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int type[OPEN_MAX];
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int nfds, nreadyfds;
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int error;
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char block;
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clock_t expiry;
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timer_t timer; /* if expiry > 0 */
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} selecttab[MAXSELECTS];
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FORWARD _PROTOTYPE(int copy_fdsets, (struct selectentry *se, int nfds,
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int direction) );
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FORWARD _PROTOTYPE(int do_select_request, (struct selectentry *se, int fd,
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int *ops) );
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FORWARD _PROTOTYPE(void filp_status, (struct filp *fp, int status) );
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FORWARD _PROTOTYPE(int is_deferred, (struct selectentry *se) );
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FORWARD _PROTOTYPE(void restart_proc, (struct selectentry *se) );
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FORWARD _PROTOTYPE(void ops2tab, (int ops, int fd, struct selectentry *e));
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FORWARD _PROTOTYPE(int is_regular_file, (struct filp *f) );
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FORWARD _PROTOTYPE(int is_pipe, (struct filp *f) );
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FORWARD _PROTOTYPE(int is_supported_major, (struct filp *f) );
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FORWARD _PROTOTYPE(void select_lock_filp, (struct filp *f, int ops) );
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FORWARD _PROTOTYPE(int select_request_async, (struct filp *f, int *ops,
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int block) );
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FORWARD _PROTOTYPE(int select_request_file, (struct filp *f, int *ops,
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int block) );
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FORWARD _PROTOTYPE(int select_request_major, (struct filp *f, int *ops,
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int block) );
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FORWARD _PROTOTYPE(int select_request_pipe, (struct filp *f, int *ops,
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int block) );
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FORWARD _PROTOTYPE(int select_request_sync, (struct filp *f, int *ops,
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int block) );
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FORWARD _PROTOTYPE(void select_cancel_all, (struct selectentry *e) );
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FORWARD _PROTOTYPE(void select_cancel_filp, (struct filp *f) );
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FORWARD _PROTOTYPE(void select_return, (struct selectentry *) );
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FORWARD _PROTOTYPE(void select_restart_filps, (void) );
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FORWARD _PROTOTYPE(int tab2ops, (int fd, struct selectentry *e) );
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FORWARD _PROTOTYPE(void wipe_select, (struct selectentry *s) );
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PRIVATE struct fdtype {
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int (*select_request)(struct filp *, int *ops, int block);
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int (*type_match)(struct filp *f);
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} fdtypes[] = {
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{ select_request_major, is_supported_major },
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{ select_request_file, is_regular_file },
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{ select_request_pipe, is_pipe },
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};
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#define SEL_FDS (sizeof(fdtypes) / sizeof(fdtypes[0]))
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PRIVATE int select_majors[] = { /* List of majors that support selecting on */
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TTY_MAJOR,
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INET_MAJOR,
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UDS_MAJOR,
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LOG_MAJOR,
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};
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#define SEL_MAJORS (sizeof(select_majors) / sizeof(select_majors[0]))
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/*===========================================================================*
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* do_select *
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*===========================================================================*/
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PUBLIC int do_select(void)
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{
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/* Implement the select(nfds, readfds, writefds, errorfds, timeout) system
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* call. First we copy the arguments and verify their sanity. Then we check
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* whether there are file descriptors that satisfy the select call right of the
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* bat. If so, or if there are no ready file descriptors but the process
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* requested to return immediately, we return the result. Otherwise we set a
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* timeout and wait for either the file descriptors to become ready or the
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* timer to go off. If no timeout value was provided, we wait indefinitely. */
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int r, nfds, do_timeout = 0, fd, s;
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struct timeval timeout;
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struct selectentry *se;
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nfds = m_in.SEL_NFDS;
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/* Sane amount of file descriptors? */
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if (nfds < 0 || nfds > OPEN_MAX) return(EINVAL);
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/* Find a slot to store this select request */
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for (s = 0; s < MAXSELECTS; s++)
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if (selecttab[s].requestor == NULL) /* Unused slot */
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break;
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if (s >= MAXSELECTS) return(ENOSPC);
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se = &selecttab[s];
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wipe_select(se); /* Clear results of previous usage */
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se->req_endpt = who_e;
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se->vir_readfds = (fd_set *) m_in.SEL_READFDS;
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se->vir_writefds = (fd_set *) m_in.SEL_WRITEFDS;
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se->vir_errorfds = (fd_set *) m_in.SEL_ERRORFDS;
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/* Copy fdsets from the process */
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if ((r = copy_fdsets(se, nfds, FROM_PROC)) != OK) return(r);
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/* Did the process set a timeout value? If so, retrieve it. */
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if (m_in.SEL_TIMEOUT != NULL) {
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do_timeout = 1;
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r = sys_vircopy(who_e, D, (vir_bytes) m_in.SEL_TIMEOUT, SELF, D,
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(vir_bytes) &timeout, sizeof(timeout));
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if (r != OK) return(r);
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}
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/* No nonsense in the timeval */
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if (do_timeout && (timeout.tv_sec < 0 || timeout.tv_usec < 0))
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return(EINVAL);
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/* If there is no timeout, we block forever. Otherwise, we block up to the
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* specified time interval.
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*/
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if (!do_timeout) /* No timeout value set */
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se->block = 1;
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else if (do_timeout && (timeout.tv_sec > 0 || timeout.tv_usec > 0))
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se->block = 1;
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else /* timeout set as (0,0) - this effects a poll */
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se->block = 0;
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se->expiry = 0; /* no timer set (yet) */
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/* Verify that file descriptors are okay to select on */
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for (fd = 0; fd < nfds; fd++) {
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struct filp *f;
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int type, ops;
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/* Because the select() interface implicitly includes file descriptors
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* you might not want to select on, we have to figure out whether we're
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* interested in them. Typically, these file descriptors include fd's
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* inherited from the parent proc and file descriptors that have been
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* close()d, but had a lower fd than one in the current set.
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*/
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if (!(ops = tab2ops(fd, se)))
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continue; /* No operations set; nothing to do for this fd */
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/* Get filp belonging to this fd */
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f = se->filps[fd] = get_filp(fd, VNODE_READ);
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if (f == NULL) {
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if (err_code == EBADF)
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r = err_code;
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else /* File descriptor is 'ready' to return EIO */
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r = EINTR;
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return(r);
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}
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/* Check file types. According to POSIX 2008:
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* "The pselect() and select() functions shall support regular files,
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* terminal and pseudo-terminal devices, FIFOs, pipes, and sockets. The
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* behavior of pselect() and select() on file descriptors that refer to
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* other types of file is unspecified."
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*
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* In our case, terminal and pseudo-terminal devices are handled by the
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* TTY major and sockets by either INET major (socket type AF_INET) or
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* PFS major (socket type AF_UNIX). PFS acts as an FS when it handles
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* pipes and as a driver when it handles sockets. Additionally, we
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* support select on the LOG major to handle kernel logging, which is
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* beyond the POSIX spec. */
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se->type[fd] = -1;
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for (type = 0; type < SEL_FDS; type++) {
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if (fdtypes[type].type_match(f)) {
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se->type[fd] = type;
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se->nfds = fd+1;
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se->filps[fd]->filp_selectors++;
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break;
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}
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}
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unlock_filp(f);
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if (se->type[fd] == -1) /* Type not found */
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return(EBADF);
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}
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/* Check all file descriptors in the set whether one is 'ready' now */
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for (fd = 0; fd < nfds; fd++) {
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int ops, r;
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struct filp *f;
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/* Again, check for involuntarily selected fd's */
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if (!(ops = tab2ops(fd, se)))
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continue; /* No operations set; nothing to do for this fd */
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/* Test filp for select operations if not already done so. e.g.,
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* processes sharing a filp and both doing a select on that filp. */
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f = se->filps[fd];
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if ((f->filp_select_ops & ops) != ops) {
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int wantops;
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wantops = (f->filp_select_ops |= ops);
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r = do_select_request(se, fd, &wantops);
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if (r != OK && r != SUSPEND)
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break; /* Error or bogus return code; abort */
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/* The select request above might have turned on/off some
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* operations because they were 'ready' or not meaningful.
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* Either way, we might have a result and we need to store them
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* in the select table entry. */
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if (wantops & ops) ops2tab(wantops, fd, se);
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}
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}
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if ((se->nreadyfds > 0 || !se->block) && !is_deferred(se)) {
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/* fd's were found that were ready to go right away, and/or
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* we were instructed not to block at all. Must return
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* immediately.
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*/
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r = copy_fdsets(se, se->nfds, TO_PROC);
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select_cancel_all(se);
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if (r != OK)
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return(r);
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else if (se->error != OK)
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return(se->error);
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return(se->nreadyfds);
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}
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/* Convert timeval to ticks and set the timer. If it fails, undo
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* all, return error.
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*/
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if (do_timeout) {
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int ticks;
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/* Open Group:
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* "If the requested timeout interval requires a finer
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* granularity than the implementation supports, the
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* actual timeout interval shall be rounded up to the next
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* supported value."
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*/
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#define USECPERSEC 1000000
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while(timeout.tv_usec >= USECPERSEC) {
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/* this is to avoid overflow with *system_hz below */
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timeout.tv_usec -= USECPERSEC;
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timeout.tv_sec++;
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}
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ticks = timeout.tv_sec * system_hz +
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(timeout.tv_usec * system_hz + USECPERSEC-1) / USECPERSEC;
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se->expiry = ticks;
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set_timer(&se->timer, ticks, select_timeout_check, s);
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}
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/* If we're blocking, the table entry is now valid */
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se->requestor = fp;
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/* process now blocked */
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suspend(FP_BLOCKED_ON_SELECT);
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return(SUSPEND);
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}
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/*===========================================================================*
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* is_deferred *
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*===========================================================================*/
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PRIVATE int is_deferred(struct selectentry *se)
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{
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/* Find out whether this select has pending initial replies */
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int fd;
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struct filp *f;
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for (fd = 0; fd < se->nfds; fd++) {
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if ((f = se->filps[fd]) == NULL) continue;
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if (f->filp_select_flags & (FSF_UPDATE|FSF_BUSY)) return(TRUE);
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}
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return(FALSE);
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}
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/*===========================================================================*
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* is_regular_file *
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*===========================================================================*/
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PRIVATE int is_regular_file(struct filp *f)
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{
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return(f && f->filp_vno && (f->filp_vno->v_mode & I_TYPE) == I_REGULAR);
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}
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/*===========================================================================*
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* is_pipe *
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*===========================================================================*/
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PRIVATE int is_pipe(struct filp *f)
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{
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/* Recognize either anonymous pipe or named pipe (FIFO) */
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return(f && f->filp_vno && (f->filp_vno->v_mode & I_TYPE) == I_NAMED_PIPE);
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}
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/*===========================================================================*
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* is_supported_major *
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*===========================================================================*/
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PRIVATE int is_supported_major(struct filp *f)
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{
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/* See if this filp is a handle on a device on which we support select() */
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int m;
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if (!(f && f->filp_vno)) return(FALSE);
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if ((f->filp_vno->v_mode & I_TYPE) != I_CHAR_SPECIAL) return(FALSE);
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for (m = 0; m < SEL_MAJORS; m++)
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if (major(f->filp_vno->v_sdev) == select_majors[m])
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return(TRUE);
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return(FALSE);
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}
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/*===========================================================================*
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* select_request_async *
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*===========================================================================*/
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PRIVATE int select_request_async(struct filp *f, int *ops, int block)
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{
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int r, rops, major;
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struct dmap *dp;
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rops = *ops;
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/* By default, nothing to do */
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*ops = 0;
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if (!block && (f->filp_select_flags & FSF_BLOCKED)) {
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/* This filp is blocked waiting for a reply, but we don't want to
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* block ourselves. Unless we're awaiting the initial reply, these
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* operations won't be ready */
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if (!(f->filp_select_flags & FSF_BUSY)) {
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if ((rops & SEL_RD) && (f->filp_select_flags & FSF_RD_BLOCK))
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rops &= ~SEL_RD;
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if ((rops & SEL_WR) && (f->filp_select_flags & FSF_WR_BLOCK))
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rops &= ~SEL_WR;
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if ((rops & SEL_ERR) && (f->filp_select_flags & FSF_ERR_BLOCK))
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rops &= ~SEL_ERR;
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if (!(rops & (SEL_RD|SEL_WR|SEL_ERR)))
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return(OK);
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}
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}
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f->filp_select_flags |= FSF_UPDATE;
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if (block) {
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rops |= SEL_NOTIFY;
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if (rops & SEL_RD) f->filp_select_flags |= FSF_RD_BLOCK;
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if (rops & SEL_WR) f->filp_select_flags |= FSF_WR_BLOCK;
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if (rops & SEL_ERR) f->filp_select_flags |= FSF_ERR_BLOCK;
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}
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if (f->filp_select_flags & FSF_BUSY)
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return(SUSPEND);
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major = major(f->filp_vno->v_sdev);
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if (major < 0 || major >= NR_DEVICES) return(ENXIO);
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dp = &dmap[major];
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if (dp->dmap_sel_filp)
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return(SUSPEND);
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f->filp_select_flags &= ~FSF_UPDATE;
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r = dev_io(VFS_DEV_SELECT, f->filp_vno->v_sdev, rops, NULL,
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cvu64(0), 0, 0, FALSE);
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if (r < 0 && r != SUSPEND)
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return(r);
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if (r != SUSPEND)
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panic("select_request_asynch: expected SUSPEND got: %d", r);
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dp->dmap_sel_filp = f;
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f->filp_select_flags |= FSF_BUSY;
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return(SUSPEND);
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}
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/*===========================================================================*
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* select_request_file *
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*===========================================================================*/
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PRIVATE int select_request_file(struct filp *UNUSED(f), int *UNUSED(ops),
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int UNUSED(block))
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{
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/* Files are always ready, so output *ops is input *ops */
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return(OK);
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}
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/*===========================================================================*
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* select_request_major *
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*===========================================================================*/
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PRIVATE int select_request_major(struct filp *f, int *ops, int block)
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{
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int major, r;
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major = major(f->filp_vno->v_sdev);
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if (major < 0 || major >= NR_DEVICES) return(ENXIO);
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if (dmap[major].dmap_style == STYLE_DEVA ||
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dmap[major].dmap_style == STYLE_CLONE_A)
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r = select_request_async(f, ops, block);
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else
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r = select_request_sync(f, ops, block);
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return(r);
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}
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|
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/*===========================================================================*
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* select_request_sync *
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*===========================================================================*/
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PRIVATE int select_request_sync(struct filp *f, int *ops, int block)
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{
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int rops;
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rops = *ops;
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if (block) rops |= SEL_NOTIFY;
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*ops = dev_io(VFS_DEV_SELECT, f->filp_vno->v_sdev, rops, NULL,
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cvu64(0), 0, 0, FALSE);
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if (*ops < 0)
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return(*ops);
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return(OK);
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}
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|
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/*===========================================================================*
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* select_request_pipe *
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*===========================================================================*/
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PRIVATE int select_request_pipe(struct filp *f, int *ops, int block)
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{
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int orig_ops, r = 0, err;
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orig_ops = *ops;
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if ((*ops & (SEL_RD|SEL_ERR))) {
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err = pipe_check(f->filp_vno, READING, 0, 1, f->filp_pos, 1);
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if (err != SUSPEND)
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r |= SEL_RD;
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if (err < 0 && err != SUSPEND)
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r |= SEL_ERR;
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if (err == SUSPEND && !(f->filp_mode & R_BIT)) {
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/* A "meaningless" read select, therefore ready
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* for reading and no error set. */
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r |= SEL_RD;
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r &= ~SEL_ERR;
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}
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}
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if ((*ops & (SEL_WR|SEL_ERR))) {
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err = pipe_check(f->filp_vno, WRITING, 0, 1, f->filp_pos, 1);
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if (err != SUSPEND)
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r |= SEL_WR;
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if (err < 0 && err != SUSPEND)
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r |= SEL_ERR;
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if (err == SUSPEND && !(f->filp_mode & W_BIT)) {
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/* A "meaningless" write select, therefore ready
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for writing and no error set. */
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r |= SEL_WR;
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r &= ~SEL_ERR;
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}
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}
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/* Some options we collected might not be requested. */
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|
*ops = r & orig_ops;
|
|
|
|
if (!*ops && block)
|
|
f->filp_pipe_select_ops |= orig_ops;
|
|
|
|
return(OK);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* 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 r;
|
|
size_t fd_setsize;
|
|
endpoint_t src_e, dst_e;
|
|
fd_set *src_fds, *dst_fds;
|
|
|
|
if (nfds < 0 || nfds > OPEN_MAX)
|
|
panic("select copy_fdsets: nfds wrong: %d", nfds);
|
|
|
|
/* Only copy back as many bits as the user expects. */
|
|
#ifdef __NBSD_LIBC
|
|
fd_setsize = (size_t) (howmany(nfds, __NFDBITS) * sizeof(__fd_mask));
|
|
#else
|
|
fd_setsize = (size_t) (_FDSETWORDS(nfds) * _FDSETBITSPERWORD/8);
|
|
#endif
|
|
|
|
/* 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 *se)
|
|
{
|
|
/* Cancel select. Decrease select usage and cancel timer */
|
|
|
|
int fd;
|
|
struct filp *f;
|
|
|
|
for (fd = 0; fd < se->nfds; fd++) {
|
|
if ((f = se->filps[fd]) == NULL) continue;
|
|
se->filps[fd] = NULL;
|
|
select_cancel_filp(f);
|
|
}
|
|
|
|
if (se->expiry > 0) {
|
|
cancel_timer(&se->timer);
|
|
se->expiry = 0;
|
|
}
|
|
|
|
se->requestor = NULL;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* select_cancel_filp *
|
|
*===========================================================================*/
|
|
PRIVATE void select_cancel_filp(struct filp *f)
|
|
{
|
|
/* Reduce number of select users of this filp */
|
|
|
|
assert(f);
|
|
assert(f->filp_selectors >= 0);
|
|
if (f->filp_selectors == 0) return;
|
|
if (f->filp_count == 0) return;
|
|
|
|
select_lock_filp(f, f->filp_select_ops);
|
|
|
|
f->filp_selectors--;
|
|
if (f->filp_selectors == 0) {
|
|
/* No one selecting on this filp anymore, forget about select state */
|
|
f->filp_select_ops = 0;
|
|
f->filp_select_flags = 0;
|
|
f->filp_pipe_select_ops = 0;
|
|
}
|
|
|
|
unlock_filp(f);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* select_return *
|
|
*===========================================================================*/
|
|
PRIVATE void select_return(struct selectentry *se)
|
|
{
|
|
int r, r1;
|
|
|
|
assert(!is_deferred(se)); /* Not done yet, first wait for async reply */
|
|
|
|
select_cancel_all(se);
|
|
|
|
r1 = copy_fdsets(se, se->nfds, TO_PROC);
|
|
if (r1 != OK)
|
|
r = r1;
|
|
else if (se->error != OK)
|
|
r = se->error;
|
|
else
|
|
r = se->nreadyfds;
|
|
|
|
revive(se->req_endpt, r);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* select_callback *
|
|
*===========================================================================*/
|
|
PUBLIC void select_callback(struct filp *f, int status)
|
|
{
|
|
filp_status(f, status);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* init_select *
|
|
*===========================================================================*/
|
|
PUBLIC void init_select(void)
|
|
{
|
|
int s;
|
|
|
|
for (s = 0; s < MAXSELECTS; s++)
|
|
init_timer(&selecttab[s].timer);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* select_forget *
|
|
*===========================================================================*/
|
|
PUBLIC void select_forget(endpoint_t proc_e)
|
|
{
|
|
/* Something has happened (e.g. signal delivered that interrupts select()).
|
|
* Totally forget about the select(). */
|
|
|
|
int slot;
|
|
struct selectentry *se;
|
|
|
|
for (slot = 0; slot < MAXSELECTS; slot++) {
|
|
se = &selecttab[slot];
|
|
if (se->requestor != NULL && se->req_endpt == proc_e)
|
|
break;
|
|
}
|
|
|
|
if (slot >= MAXSELECTS) return; /* Entry not found */
|
|
se->error = EINTR;
|
|
if (is_deferred(se)) return; /* Still awaiting initial reply */
|
|
|
|
select_cancel_all(se);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* 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) return; /* Entry does not exist */
|
|
|
|
se = &selecttab[s];
|
|
if (se->requestor == NULL) return;
|
|
fp = se->requestor;
|
|
if (se->expiry <= 0) return; /* Strange, did we even ask for a timeout? */
|
|
se->expiry = 0;
|
|
if (is_deferred(se)) return; /* Wait for initial replies to DEV_SELECT */
|
|
select_return(se);
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* select_unsuspend_by_endpt *
|
|
*===========================================================================*/
|
|
PUBLIC void select_unsuspend_by_endpt(endpoint_t proc_e)
|
|
{
|
|
/* Revive blocked processes when a driver has disappeared */
|
|
|
|
int fd, s, major;
|
|
struct selectentry *se;
|
|
struct filp *f;
|
|
|
|
for (s = 0; s < MAXSELECTS; s++) {
|
|
int wakehim = 0;
|
|
se = &selecttab[s];
|
|
if (se->requestor == NULL) continue;
|
|
if (se->requestor->fp_endpoint == proc_e) {
|
|
assert(se->requestor->fp_flags & FP_EXITING);
|
|
select_cancel_all(se);
|
|
continue;
|
|
}
|
|
|
|
for (fd = 0; fd < se->nfds; fd++) {
|
|
if ((f = se->filps[fd]) == NULL || f->filp_vno == NULL)
|
|
continue;
|
|
|
|
major = major(f->filp_vno->v_sdev);
|
|
if (dmap_driver_match(proc_e, major)) {
|
|
se->filps[fd] = NULL;
|
|
se->error = EINTR;
|
|
select_cancel_filp(f);
|
|
wakehim = 1;
|
|
}
|
|
}
|
|
|
|
if (wakehim && !is_deferred(se))
|
|
select_return(se);
|
|
}
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* select_reply1 *
|
|
*===========================================================================*/
|
|
PUBLIC void select_reply1(driver_e, minor, status)
|
|
endpoint_t driver_e;
|
|
int minor;
|
|
int status;
|
|
{
|
|
/* Handle reply to DEV_SELECT request */
|
|
|
|
int major;
|
|
dev_t dev;
|
|
struct filp *f;
|
|
struct dmap *dp;
|
|
struct vnode *vp;
|
|
|
|
/* Figure out which device is replying */
|
|
if ((dp = get_dmap(driver_e)) == NULL) return;
|
|
|
|
major = dp-dmap;
|
|
dev = makedev(major, minor);
|
|
|
|
/* Get filp belonging to character special file */
|
|
if ((f = dp->dmap_sel_filp) == NULL) {
|
|
printf("VFS (%s:%d): major %d was not expecting a DEV_SELECT reply\n",
|
|
__FILE__, __LINE__, major);
|
|
return;
|
|
}
|
|
|
|
/* Is the filp still in use and busy waiting for a reply? The owner might
|
|
* have vanished before the driver was able to reply. */
|
|
if (f->filp_count >= 1 && (f->filp_select_flags & FSF_BUSY)) {
|
|
/* Find vnode and check we got a reply from the device we expected */
|
|
vp = f->filp_vno;
|
|
assert(vp != NULL);
|
|
assert((vp->v_mode & I_TYPE) == I_CHAR_SPECIAL); /* Must be char. special */
|
|
if (vp->v_sdev != dev) {
|
|
printf("VFS (%s:%d): expected reply from dev %d not %d\n",
|
|
__FILE__, __LINE__, vp->v_sdev, dev);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* No longer waiting for a reply from this device */
|
|
dp->dmap_sel_filp = NULL;
|
|
|
|
/* Process select result only if requestor is still around. That is, the
|
|
* corresponding filp is still in use.
|
|
*/
|
|
if (f->filp_count >= 1) {
|
|
select_lock_filp(f, f->filp_select_ops);
|
|
f->filp_select_flags &= ~FSF_BUSY;
|
|
|
|
/* The select call is done now, except when
|
|
* - another process started a select on the same filp with possibly a
|
|
* different set of operations.
|
|
* - a process does a select on the same filp but using different file
|
|
* descriptors.
|
|
* - the select has a timeout. Upon receiving this reply the operations
|
|
* might not be ready yet, so we want to wait for that to ultimately
|
|
* happen.
|
|
* Therefore we need to keep remembering what the operations are.
|
|
*/
|
|
if (!(f->filp_select_flags & (FSF_UPDATE|FSF_BLOCKED)))
|
|
f->filp_select_ops = 0; /* done selecting */
|
|
else if (!(f->filp_select_flags & FSF_UPDATE))
|
|
/* there may be operations pending */
|
|
f->filp_select_ops &= ~status;
|
|
|
|
/* Record new filp status */
|
|
if (!(status == 0 && (f->filp_select_flags & FSF_BLOCKED))) {
|
|
if (status > 0) { /* operations ready */
|
|
if (status & SEL_RD)
|
|
f->filp_select_flags &= ~FSF_RD_BLOCK;
|
|
if (status & SEL_WR)
|
|
f->filp_select_flags &= ~FSF_WR_BLOCK;
|
|
if (status & SEL_ERR)
|
|
f->filp_select_flags &= ~FSF_ERR_BLOCK;
|
|
} else if (status < 0) { /* error */
|
|
/* Always unblock upon error */
|
|
f->filp_select_flags &= ~FSF_BLOCKED;
|
|
}
|
|
}
|
|
|
|
unlock_filp(f);
|
|
filp_status(f, status); /* Tell filp owners about the results */
|
|
}
|
|
|
|
select_restart_filps();
|
|
}
|
|
|
|
|
|
/*===========================================================================*
|
|
* select_reply2 *
|
|
*===========================================================================*/
|
|
PUBLIC void select_reply2(driver_e, minor, status)
|
|
endpoint_t driver_e;
|
|
int minor;
|
|
int status;
|
|
{
|
|
/* Handle secondary reply to DEV_SELECT request. A secondary reply occurs when
|
|
* the select request is 'blocking' until an operation becomes ready. */
|
|
int major, slot, fd;
|
|
dev_t dev;
|
|
struct filp *f;
|
|
struct dmap *dp;
|
|
struct vnode *vp;
|
|
struct selectentry *se;
|
|
|
|
if (status == 0) {
|
|
printf("VFS (%s:%d): weird status (%d) to report\n",
|
|
__FILE__, __LINE__, status);
|
|
return;
|
|
}
|
|
|
|
/* Figure out which device is replying */
|
|
if ((dp = get_dmap(driver_e)) == NULL) {
|
|
printf("VFS (%s:%d): endpoint %d is not a known driver endpoint\n",
|
|
__FILE__, __LINE__, driver_e);
|
|
return;
|
|
}
|
|
major = dp-dmap;
|
|
dev = makedev(major, minor);
|
|
|
|
/* Find all file descriptors selecting for this device */
|
|
for (slot = 0; slot < MAXSELECTS; slot++) {
|
|
se = &selecttab[slot];
|
|
if (se->requestor == NULL) continue; /* empty slot */
|
|
|
|
for (fd = 0; fd < se->nfds; fd++) {
|
|
if ((f = se->filps[fd]) == NULL) continue;
|
|
if ((vp = f->filp_vno) == NULL) continue;
|
|
if ((vp->v_mode & I_TYPE) != I_CHAR_SPECIAL) continue;
|
|
if (vp->v_sdev != dev) continue;
|
|
|
|
select_lock_filp(f, f->filp_select_ops);
|
|
if (status > 0) { /* Operations ready */
|
|
/* Clear the replied bits from the request
|
|
* mask unless FSF_UPDATE is set.
|
|
*/
|
|
if (!(f->filp_select_flags & FSF_UPDATE))
|
|
f->filp_select_ops &= ~status;
|
|
if (status & SEL_RD)
|
|
f->filp_select_flags &= ~FSF_RD_BLOCK;
|
|
if (status & SEL_WR)
|
|
f->filp_select_flags &= ~FSF_WR_BLOCK;
|
|
if (status & SEL_ERR)
|
|
f->filp_select_flags &= ~FSF_ERR_BLOCK;
|
|
|
|
ops2tab(status, fd, se);
|
|
} else {
|
|
f->filp_select_flags &= ~FSF_BLOCKED;
|
|
ops2tab(SEL_RD|SEL_WR|SEL_ERR, fd, se);
|
|
}
|
|
unlock_filp(f);
|
|
if (se->nreadyfds > 0) restart_proc(se);
|
|
}
|
|
}
|
|
|
|
select_restart_filps();
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* select_restart_filps *
|
|
*===========================================================================*/
|
|
PRIVATE void select_restart_filps()
|
|
{
|
|
int fd, slot;
|
|
struct filp *f;
|
|
struct vnode *vp;
|
|
struct selectentry *se;
|
|
|
|
/* Locate filps that can be restarted */
|
|
for (slot = 0; slot < MAXSELECTS; slot++) {
|
|
se = &selecttab[slot];
|
|
if (se->requestor == NULL) continue; /* empty slot */
|
|
|
|
/* Only 'deferred' processes are eligible to restart */
|
|
if (!is_deferred(se)) continue;
|
|
|
|
/* Find filps that are not waiting for a reply, but have an updated
|
|
* status (i.e., another select on the same filp with possibly a
|
|
* different set of operations is to be done), and thus requires the
|
|
* select request to be sent again).
|
|
*/
|
|
for (fd = 0; fd < se->nfds; fd++) {
|
|
int r, wantops, ops;
|
|
if ((f = se->filps[fd]) == NULL) continue;
|
|
if (f->filp_select_flags & FSF_BUSY) /* Still waiting for */
|
|
continue; /* initial reply */
|
|
if (!(f->filp_select_flags & FSF_UPDATE)) /* Must be in */
|
|
continue; /* 'update' state */
|
|
|
|
wantops = ops = f->filp_select_ops;
|
|
vp = f->filp_vno;
|
|
assert((vp->v_mode & I_TYPE) == I_CHAR_SPECIAL);
|
|
r = do_select_request(se, fd, &wantops);
|
|
if (r != OK && r != SUSPEND)
|
|
break; /* Error or bogus return code; abort */
|
|
if (wantops & ops) ops2tab(wantops, fd, se);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* do_select_request *
|
|
*===========================================================================*/
|
|
PRIVATE int do_select_request(se, fd, ops)
|
|
struct selectentry *se;
|
|
int fd;
|
|
int *ops;
|
|
{
|
|
/* Perform actual select request for file descriptor fd */
|
|
|
|
int r, type;
|
|
struct filp *f;
|
|
|
|
type = se->type[fd];
|
|
f = se->filps[fd];
|
|
select_lock_filp(f, *ops);
|
|
r = fdtypes[type].select_request(f, ops, se->block);
|
|
unlock_filp(f);
|
|
if (r != OK && r != SUSPEND) {
|
|
se->error = EINTR;
|
|
se->block = 0; /* Stop blocking to return asap */
|
|
if (!is_deferred(se)) select_cancel_all(se);
|
|
}
|
|
|
|
return(r);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* filp_status *
|
|
*===========================================================================*/
|
|
PRIVATE void filp_status(f, status)
|
|
struct filp *f;
|
|
int status;
|
|
{
|
|
/* Tell processes that need to know about the status of this filp */
|
|
int fd, slot;
|
|
struct selectentry *se;
|
|
|
|
for (slot = 0; slot < MAXSELECTS; slot++) {
|
|
se = &selecttab[slot];
|
|
if (se->requestor == NULL) continue; /* empty slot */
|
|
|
|
for (fd = 0; fd < se->nfds; fd++) {
|
|
if (se->filps[fd] != f) continue;
|
|
if (status < 0)
|
|
ops2tab(SEL_RD|SEL_WR|SEL_ERR, fd, se);
|
|
else
|
|
ops2tab(status, fd, se);
|
|
restart_proc(se);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* restart_proc *
|
|
*===========================================================================*/
|
|
PRIVATE void restart_proc(se)
|
|
struct selectentry *se;
|
|
{
|
|
/* Tell process about select results (if any) unless there are still results
|
|
* pending. */
|
|
|
|
if ((se->nreadyfds > 0 || !se->block) && !is_deferred(se))
|
|
select_return(se);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* wipe_select *
|
|
*===========================================================================*/
|
|
PRIVATE void wipe_select(struct selectentry *se)
|
|
{
|
|
se->nfds = 0;
|
|
se->nreadyfds = 0;
|
|
se->error = OK;
|
|
se->block = 0;
|
|
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);
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* select_lock_filp *
|
|
*===========================================================================*/
|
|
PRIVATE void select_lock_filp(struct filp *f, int ops)
|
|
{
|
|
/* Lock a filp and vnode based on which operations are requested */
|
|
tll_access_t locktype;;
|
|
|
|
locktype = VNODE_READ; /* By default */
|
|
|
|
if (ops & (SEL_WR|SEL_ERR))
|
|
/* Selecting for error or writing requires exclusive access */
|
|
locktype = VNODE_WRITE;
|
|
|
|
lock_filp(f, locktype);
|
|
}
|