diff options
Diffstat (limited to 'lib/libsys/kqueue.2')
| -rw-r--r-- | lib/libsys/kqueue.2 | 89 |
1 files changed, 87 insertions, 2 deletions
diff --git a/lib/libsys/kqueue.2 b/lib/libsys/kqueue.2 index d6e949baa24c..a8ebabf02cf7 100644 --- a/lib/libsys/kqueue.2 +++ b/lib/libsys/kqueue.2 @@ -22,7 +22,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd March 26, 2023 +.Dd September 12, 2025 .Dt KQUEUE 2 .Os .Sh NAME @@ -97,10 +97,37 @@ system call also creates a new kernel event queue, and additionally takes a .Fa flags argument, which is a bitwise-inclusive OR of the following flags: -.Bl -tag -width "KQUEUE_CLOEXEC" +.Bl -tag -width "KQUEUE_CPONFORK" .It Dv KQUEUE_CLOEXEC The returned file descriptor is automatically closed on .Xr execve 2 +.It Dv KQUEUE_CPONFORK +When this flag is set, the created kqueue is copied into +the child process on +.Xr fork 2 +calls. +The kqueue descriptor index of the new kqueue will be inherited by the child, +that is, the numeric value of the descriptor will remain the same. +.Pp +Copying is deep, that is, each registered event in the original kqueue is +copied (and not shared) into the new kqueue. +This is contrary to how other descriptor types are handled upon +.Xr fork 2 , +where the copied file descriptor references the same file object +as the source descriptor (shallow copy). +.Pp +By default, in other words, when the flag is not set, kqueues from +the parent are not copied on fork to the child process. +The corresponding file descriptor indeces are unused in the child. +.Pp +Registered events that reference file descriptors which are not +duplicated on fork, are not copied into the new kqueue. +For instance, if the event references a file descriptor opened with the +.Dv O_CLOEXEC +flag set, it is not copied. +Similarly, if event references a kqueue opened without the +.Dv KQUEUE_CPONFORK +flag, the event is not copied. .El .Pp The @@ -593,6 +620,64 @@ returns the number of times the signal has occurred since the last call to This filter automatically sets the .Dv EV_CLEAR flag internally. +.It Dv EVFILT_JAIL +Takes the jail ID to monitor as the identifier and the events to watch for +in +.Va fflags , +and returns when the jail performs one or more of the requested events. +If a process can normally see a jail, it can attach an event to it. +An identifier of zero will watch the process's own jail. +The events to monitor are: +.Bl -tag -width "Dv NOTE_JAIL_ATTACH" +.It Dv NOTE_JAIL_SET +The jail has been changed via +.Xr jail_set 2 . +.It Dv NOTE_JAIL_ATTACH +A process has attached to the jail via +.Xr jail_attach 2 +or a similar call. +The process ID will be stored in +.Va data . +If more than one process has attached since the last call to +.Fn kevent , +.Va data +will be zero. +.It Dv NOTE_JAIL_REMOVE +The jail has been removed. +.It Dv NOTE_JAIL_CHILD +A child of the watched jail has been created. +Its jail ID will be stored in +.Va data . +If more than one jail has been created since the last call to +.Fn kevent , +.Va data +will be zero. +.El +.Pp +On return, +.Va fflags +contains the events which triggered the filter. +It will also contain +.Dv NOTE_JAIL_MULTI +if more than one +.Dv NOTE_JAIL_ATTACH +or +.Dv NOTE_JAIL_CHILD +event has been received since the last call to +.Fn kevent . +.It Dv EVFILT_JAILDESC +Takes a jail descriptor returned by +.Xr jail_set 2 +or +.Xr jail_get 2 +as the identifier and the events to watch for in +.Va fflags , +and returns when the jail performs one or more of the requested events. +The events to monitor and the resulting +.Va fflags +are the same as those listed in +.Dv EVFILT_JAIL , +above. .It Dv EVFILT_TIMER Establishes an arbitrary timer identified by .Va ident . |