On Thu, Sep 14, 2023 at 01:12:22PM +0300, Vitaliy Makkoveev wrote:
> `log_mtx' mutex(9) already used for message buffer protection, so use it
> to protect `logread_filtops' too.
>
> ok?
OK bluhm@
> Index: sys/kern/subr_log.c
> ===================================================================
> RCS file: /cvs/src/sys/kern/subr_log.c,v
> retrieving revision 1.77
> diff -u -p -r1.77 subr_log.c
> --- sys/kern/subr_log.c 14 Jul 2023 07:07:08 -0000 1.77
> +++ sys/kern/subr_log.c 14 Sep 2023 10:04:41 -0000
> @@ -50,6 +50,7 @@
> #include <sys/filedesc.h>
> #include <sys/socket.h>
> #include <sys/socketvar.h>
> +#include <sys/event.h>
> #include <sys/fcntl.h>
> #include <sys/mutex.h>
> #include <sys/timeout.h>
> @@ -75,7 +76,7 @@
> */
> struct logsoftc {
> int sc_state; /* [L] see above for possibilities */
> - struct selinfo sc_selp; /* process waiting on select call */
> + struct klist sc_klist; /* process waiting on kevent call */
> struct sigio_ref sc_sigio; /* async I/O registration */
> int sc_need_wakeup; /* if set, wake up waiters */
> struct timeout sc_tick; /* wakeup poll timeout */
> @@ -99,12 +100,16 @@ struct mutex log_mtx =
>
> void filt_logrdetach(struct knote *kn);
> int filt_logread(struct knote *kn, long hint);
> +int filt_logmodify(struct kevent *, struct knote *);
> +int filt_logprocess(struct knote *, struct kevent *);
>
> const struct filterops logread_filtops = {
> - .f_flags = FILTEROP_ISFD,
> + .f_flags = FILTEROP_ISFD | FILTEROP_MPSAFE,
> .f_attach = NULL,
> .f_detach = filt_logrdetach,
> .f_event = filt_logread,
> + .f_modify = filt_logmodify,
> + .f_process = filt_logprocess,
> };
>
> int dosendsyslog(struct proc *, const char *, size_t, int, enum uio_seg);
> @@ -191,11 +196,9 @@ msgbuf_getlen(struct msgbuf *mbp)
> {
> long len;
>
> - mtx_enter(&log_mtx);
> len = mbp->msg_bufx - mbp->msg_bufr;
> if (len < 0)
> len += mbp->msg_bufs;
> - mtx_leave(&log_mtx);
> return (len);
> }
>
> @@ -205,6 +208,7 @@ logopen(dev_t dev, int flags, int mode,
> if (log_open)
> return (EBUSY);
> log_open = 1;
> + klist_init_mutex(&logsoftc.sc_klist, &log_mtx);
> sigio_init(&logsoftc.sc_sigio);
> timeout_set(&logsoftc.sc_tick, logtick, NULL);
> timeout_add_msec(&logsoftc.sc_tick, LOG_TICK);
> @@ -225,6 +229,10 @@ logclose(dev_t dev, int flag, int mode,
> FRELE(fp, p);
> log_open = 0;
> timeout_del(&logsoftc.sc_tick);
> +
> + klist_invalidate(&logsoftc.sc_klist);
> + klist_free(&logsoftc.sc_klist);
> +
> logsoftc.sc_state = 0;
> sigio_free(&logsoftc.sc_sigio);
> return (0);
> @@ -301,11 +309,10 @@ int
> logkqfilter(dev_t dev, struct knote *kn)
> {
> struct klist *klist;
> - int s;
>
> switch (kn->kn_filter) {
> case EVFILT_READ:
> - klist = &logsoftc.sc_selp.si_note;
> + klist = &logsoftc.sc_klist;
> kn->kn_fop = &logread_filtops;
> break;
> default:
> @@ -313,10 +320,7 @@ logkqfilter(dev_t dev, struct knote *kn)
> }
>
> kn->kn_hook = (void *)msgbufp;
> -
> - s = splhigh();
> - klist_insert_locked(klist, kn);
> - splx(s);
> + klist_insert(klist, kn);
>
> return (0);
> }
> @@ -324,11 +328,7 @@ logkqfilter(dev_t dev, struct knote *kn)
> void
> filt_logrdetach(struct knote *kn)
> {
> - int s;
> -
> - s = splhigh();
> - klist_remove_locked(&logsoftc.sc_selp.si_note, kn);
> - splx(s);
> + klist_remove(&logsoftc.sc_klist, kn);
> }
>
> int
> @@ -340,6 +340,30 @@ filt_logread(struct knote *kn, long hint
> return (kn->kn_data != 0);
> }
>
> +int
> +filt_logmodify(struct kevent *kev, struct knote *kn)
> +{
> + int active;
> +
> + mtx_enter(&log_mtx);
> + active = knote_modify(kev, kn);
> + mtx_leave(&log_mtx);
> +
> + return (active);
> +}
> +
> +int
> +filt_logprocess(struct knote *kn, struct kevent *kev)
> +{
> + int active;
> +
> + mtx_enter(&log_mtx);
> + active = knote_process(kn, kev);
> + mtx_leave(&log_mtx);
> +
> + return (active);
> +}
> +
> void
> logwakeup(void)
> {
> @@ -380,9 +404,9 @@ logtick(void *arg)
> state = logsoftc.sc_state;
> if (logsoftc.sc_state & LOG_RDWAIT)
> logsoftc.sc_state &= ~LOG_RDWAIT;
> + knote_locked(&logsoftc.sc_klist, 0);
> mtx_leave(&log_mtx);
>
> - selwakeup(&logsoftc.sc_selp);
> if (state & LOG_ASYNC)
> pgsigio(&logsoftc.sc_sigio, SIGIO, 0);
> if (state & LOG_RDWAIT)
> @@ -401,7 +425,9 @@ logioctl(dev_t dev, u_long com, caddr_t
>
> /* return number of characters immediately available */
> case FIONREAD:
> + mtx_enter(&log_mtx);
> *(int *)data = (int)msgbuf_getlen(msgbufp);
> + mtx_leave(&log_mtx);
> break;
>
> case FIONBIO:
