The branch stable/15 has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=2002e07123202a0b86f7220a78786eec71c61070
commit 2002e07123202a0b86f7220a78786eec71c61070 Author: Konstantin Belousov <[email protected]> AuthorDate: 2025-08-19 04:34:04 +0000 Commit: Konstantin Belousov <[email protected]> CommitDate: 2025-11-01 00:43:14 +0000 kqueuex(2): add KQUEUE_CPONFORK (cherry picked from commit b11289f87123f8ae06fc70bc70d26a25d4356a65) --- sys/compat/linux/linux_event.c | 2 +- sys/kern/kern_event.c | 174 ++++++++++++++++++++++++++++++++++++++--- sys/sys/event.h | 2 + sys/sys/eventvar.h | 2 + sys/sys/syscallsubr.h | 3 +- 5 files changed, 168 insertions(+), 15 deletions(-) diff --git a/sys/compat/linux/linux_event.c b/sys/compat/linux/linux_event.c index e88791659f1f..fc3ef7c3e90a 100644 --- a/sys/compat/linux/linux_event.c +++ b/sys/compat/linux/linux_event.c @@ -104,7 +104,7 @@ static int epoll_create_common(struct thread *td, int flags) { - return (kern_kqueue(td, flags, NULL)); + return (kern_kqueue(td, flags, false, NULL)); } #ifdef LINUX_LEGACY_SYSCALLS diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c index 59d3e39aef93..7a6c395df86f 100644 --- a/sys/kern/kern_event.c +++ b/sys/kern/kern_event.c @@ -134,6 +134,7 @@ static fo_kqfilter_t kqueue_kqfilter; static fo_stat_t kqueue_stat; static fo_close_t kqueue_close; static fo_fill_kinfo_t kqueue_fill_kinfo; +static fo_fork_t kqueue_fork; static const struct fileops kqueueops = { .fo_read = invfo_rdwr, @@ -148,7 +149,9 @@ static const struct fileops kqueueops = { .fo_chown = invfo_chown, .fo_sendfile = invfo_sendfile, .fo_cmp = file_kcmp_generic, + .fo_fork = kqueue_fork, .fo_fill_kinfo = kqueue_fill_kinfo, + .fo_flags = DFLAG_FORK, }; static int knote_attach(struct knote *kn, struct kqueue *kq); @@ -1151,7 +1154,7 @@ int sys_kqueue(struct thread *td, struct kqueue_args *uap) { - return (kern_kqueue(td, 0, NULL)); + return (kern_kqueue(td, 0, false, NULL)); } int @@ -1159,27 +1162,30 @@ sys_kqueuex(struct thread *td, struct kqueuex_args *uap) { int flags; - if ((uap->flags & ~(KQUEUE_CLOEXEC)) != 0) + if ((uap->flags & ~(KQUEUE_CLOEXEC | KQUEUE_CPONFORK)) != 0) return (EINVAL); flags = 0; if ((uap->flags & KQUEUE_CLOEXEC) != 0) flags |= O_CLOEXEC; - return (kern_kqueue(td, flags, NULL)); + return (kern_kqueue(td, flags, (uap->flags & KQUEUE_CPONFORK) != 0, + NULL)); } static void -kqueue_init(struct kqueue *kq) +kqueue_init(struct kqueue *kq, bool cponfork) { mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK); TAILQ_INIT(&kq->kq_head); knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); + if (cponfork) + kq->kq_state |= KQ_CPONFORK; } static int kern_kqueue_alloc(struct thread *td, struct filedesc *fdp, int *fdip, - struct file **fpp, int flags, struct filecaps *fcaps, + struct file **fpp, int flags, struct filecaps *fcaps, bool cponfork, struct kqueue **kqp) { struct ucred *cred; @@ -1191,7 +1197,7 @@ kern_kqueue_alloc(struct thread *td, struct filedesc *fdp, int *fdip, return (ENOMEM); error = fdip != NULL ? falloc_caps(td, fpp, fdip, flags, fcaps) : - _falloc_noinstall(td, fpp, 2); + _falloc_noinstall(td, fpp, 1); if (error != 0) { chgkqcnt(cred->cr_ruidinfo, -1, 0); return (error); @@ -1199,31 +1205,33 @@ kern_kqueue_alloc(struct thread *td, struct filedesc *fdp, int *fdip, /* An extra reference on `fp' has been held for us by falloc(). */ kq = malloc(sizeof(*kq), M_KQUEUE, M_WAITOK | M_ZERO); - kqueue_init(kq); + kqueue_init(kq, cponfork); kq->kq_fdp = fdp; kq->kq_cred = crhold(cred); - FILEDESC_XLOCK(fdp); + if (fdip != NULL) + FILEDESC_XLOCK(fdp); TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); - FILEDESC_XUNLOCK(fdp); + if (fdip != NULL) + FILEDESC_XUNLOCK(fdp); + finit(*fpp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); *kqp = kq; return (0); } int -kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps) +kern_kqueue(struct thread *td, int flags, bool cponfork, struct filecaps *fcaps) { struct kqueue *kq; struct file *fp; int fd, error; error = kern_kqueue_alloc(td, td->td_proc->p_fd, &fd, &fp, flags, - fcaps, &kq); + fcaps, cponfork, &kq); if (error != 0) return (error); - finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); fdrop(fp, td); td->td_retval[0] = fd; @@ -1504,7 +1512,7 @@ kern_kevent_anonymous(struct thread *td, int nevents, struct kqueue kq = {}; int error; - kqueue_init(&kq); + kqueue_init(&kq, false); kq.kq_refcnt = 1; error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); kqueue_drain(&kq, td); @@ -2958,6 +2966,146 @@ noacquire: return (error); } +static int +kqueue_fork_alloc(struct filedesc *fdp, struct file *fp, struct file **fp1, + struct thread *td) +{ + struct kqueue *kq, *kq1; + int error; + + MPASS(fp->f_type == DTYPE_KQUEUE); + kq = fp->f_data; + if ((kq->kq_state & KQ_CPONFORK) == 0) + return (EOPNOTSUPP); + error = kqueue_acquire_ref(kq); + if (error != 0) + return (error); + error = kern_kqueue_alloc(td, fdp, NULL, fp1, 0, NULL, true, &kq1); + if (error == 0) { + kq1->kq_forksrc = kq; + (*fp1)->f_flag = fp->f_flag & (FREAD | FWRITE | FEXEC | + O_CLOEXEC | O_CLOFORK); + } else { + kqueue_release(kq, 0); + } + return (error); +} + +static void +kqueue_fork_copy_knote(struct kqueue *kq1, struct knote *kn, struct proc *p1, + struct filedesc *fdp) +{ + struct knote *kn1; + const struct filterops *fop; + int error; + + fop = kn->kn_fop; + if (fop->f_copy == NULL || (fop->f_isfd && + fdp->fd_files->fdt_ofiles[kn->kn_kevent.ident].fde_file == NULL)) + return; + error = kqueue_expand(kq1, fop, kn->kn_kevent.ident, M_WAITOK); + if (error != 0) + return; + + kn1 = knote_alloc(M_WAITOK); + *kn1 = *kn; + kn1->kn_status |= KN_DETACHED; + kn1->kn_status &= ~KN_QUEUED; + kn1->kn_kq = kq1; + error = fop->f_copy(kn1, p1); + if (error != 0) { + knote_free(kn1); + return; + } + (void)kqueue_fo_find(kn->kn_kevent.filter); + if (fop->f_isfd && !fhold(kn1->kn_fp)) { + fop->f_detach(kn1); + kqueue_fo_release(kn->kn_kevent.filter); + knote_free(kn1); + return; + } + if (kn->kn_knlist != NULL) + knlist_add(kn->kn_knlist, kn1, 0); + KQ_LOCK(kq1); + knote_attach(kn1, kq1); + kn1->kn_influx = 0; + if ((kn->kn_status & KN_QUEUED) != 0) + knote_enqueue(kn1); + KQ_UNLOCK(kq1); +} + +static void +kqueue_fork_copy_list(struct klist *knlist, struct knote *marker, + struct kqueue *kq, struct kqueue *kq1, struct proc *p1, + struct filedesc *fdp) +{ + struct knote *kn; + + KQ_OWNED(kq); + kn = SLIST_FIRST(knlist); + while (kn != NULL) { + if ((kn->kn_status & KN_DETACHED) != 0 || + (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0)) { + kn = SLIST_NEXT(kn, kn_link); + continue; + } + kn_enter_flux(kn); + SLIST_INSERT_AFTER(kn, marker, kn_link); + KQ_UNLOCK(kq); + kqueue_fork_copy_knote(kq1, kn, p1, fdp); + KQ_LOCK(kq); + kn_leave_flux(kn); + kn = SLIST_NEXT(marker, kn_link); + /* XXXKIB switch kn_link to LIST? */ + SLIST_REMOVE(knlist, marker, knote, kn_link); + } +} + +static int +kqueue_fork_copy(struct filedesc *fdp, struct file *fp, struct file *fp1, + struct proc *p1, struct thread *td) +{ + struct kqueue *kq, *kq1; + struct knote *marker; + int error, i; + + error = 0; + MPASS(fp == NULL); + MPASS(fp1->f_type == DTYPE_KQUEUE); + + kq1 = fp1->f_data; + kq = kq1->kq_forksrc; + marker = knote_alloc(M_WAITOK); + marker->kn_status = KN_MARKER; + + KQ_LOCK(kq); + for (i = 0; i < kq->kq_knlistsize; i++) { + kqueue_fork_copy_list(&kq->kq_knlist[i], marker, kq, kq1, + p1, fdp); + } + if (kq->kq_knhashmask != 0) { + for (i = 0; i <= kq->kq_knhashmask; i++) { + kqueue_fork_copy_list(&kq->kq_knhash[i], marker, kq, + kq1, p1, fdp); + } + } + kqueue_release(kq, 1); + kq1->kq_forksrc = NULL; + KQ_UNLOCK(kq); + + knote_free(marker); + return (error); +} + +static int +kqueue_fork(struct filedesc *fdp, struct file *fp, struct file **fp1, + struct proc *p1, struct thread *td) +{ + if (*fp1 == NULL) + return (kqueue_fork_alloc(fdp, fp, fp1, td)); + return (kqueue_fork_copy(fdp, fp, *fp1, p1, td)); +} + struct knote_status_export_bit { int kn_status_bit; int knt_status_bit; diff --git a/sys/sys/event.h b/sys/sys/event.h index 084eaafcbdc0..6e71445f03b0 100644 --- a/sys/sys/event.h +++ b/sys/sys/event.h @@ -228,6 +228,7 @@ struct freebsd11_kevent32 { /* Flags for kqueuex(2) */ #define KQUEUE_CLOEXEC 0x00000001 /* close on exec */ +#define KQUEUE_CPONFORK 0x00000002 /* copy on fork */ struct knote; SLIST_HEAD(klist, knote); @@ -283,6 +284,7 @@ struct filterops { void (*f_touch)(struct knote *kn, struct kevent *kev, u_long type); int (*f_userdump)(struct proc *p, struct knote *kn, struct kinfo_knote *kin); + int (*f_copy)(struct knote *kn, struct proc *p1); }; /* diff --git a/sys/sys/eventvar.h b/sys/sys/eventvar.h index 7fec444447f9..7cb3269f1fdf 100644 --- a/sys/sys/eventvar.h +++ b/sys/sys/eventvar.h @@ -55,12 +55,14 @@ struct kqueue { #define KQ_CLOSING 0x10 #define KQ_TASKSCHED 0x20 /* task scheduled */ #define KQ_TASKDRAIN 0x40 /* waiting for task to drain */ +#define KQ_CPONFORK 0x80 int kq_knlistsize; /* size of knlist */ struct klist *kq_knlist; /* list of knotes */ u_long kq_knhashmask; /* size of knhash */ struct klist *kq_knhash; /* hash table for knotes */ struct task kq_task; struct ucred *kq_cred; + struct kqueue *kq_forksrc; }; #endif /* !_SYS_EVENTVAR_H_ */ diff --git a/sys/sys/syscallsubr.h b/sys/sys/syscallsubr.h index 8237165b84ce..d32690634059 100644 --- a/sys/sys/syscallsubr.h +++ b/sys/sys/syscallsubr.h @@ -211,7 +211,8 @@ int kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, struct kevent_copyops *k_ops, const struct timespec *timeout); int kern_kill(struct thread *td, pid_t pid, int signum); -int kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps); +int kern_kqueue(struct thread *td, int flags, bool cponfork, + struct filecaps *fcaps); int kern_kldload(struct thread *td, const char *file, int *fileid); int kern_kldstat(struct thread *td, int fileid, struct kld_file_stat *stat); int kern_kldunload(struct thread *td, int fileid, int flags);
