diff options
| author | Martin Pieuchot <mpi@cvs.openbsd.org> | 2020-08-13 11:26:40 +0000 |
|---|---|---|
| committer | Martin Pieuchot <mpi@cvs.openbsd.org> | 2020-08-13 11:26:40 +0000 |
| commit | bbaf42c1175df984baa58b30aabcee656f39d66c (patch) | |
| tree | 43aa8cfe6eff15e1df36a6c381286af05ac4a289 | |
| parent | 6e2b3bb17fd24dcdbf8b2011a9668299a05dd9a1 (diff) | |
Document ioctl interface.
| -rw-r--r-- | share/man/man4/dt.4 | 64 |
1 files changed, 60 insertions, 4 deletions
diff --git a/share/man/man4/dt.4 b/share/man/man4/dt.4 index fffc7758286..57423fdf7c0 100644 --- a/share/man/man4/dt.4 +++ b/share/man/man4/dt.4 @@ -1,4 +1,4 @@ -.\" $OpenBSD: dt.4,v 1.5 2020/05/18 07:03:44 jmc Exp $ +.\" $OpenBSD: dt.4,v 1.6 2020/08/13 11:26:39 mpi Exp $ .\" .\" Copyright (c) 2019 Martin Pieuchot <mpi@openbsd.org> .\" @@ -14,7 +14,7 @@ .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" -.Dd $Mdocdate: May 18 2020 $ +.Dd $Mdocdate: August 13 2020 $ .Dt DT 4 .Os .Sh NAME @@ -33,13 +33,69 @@ This device can only be opened when the .Va kern.allowdt .Xr sysctl 2 variable is set. -.\"Sh IOCTL INTERFACE -.\" +.Sh IOCTL INTERFACE +The +.Xr ioctl 2 +command codes below are defined in +.In dev/dt/dtvar.h . +.Bl -tag -width xxxxxx +.It Dv DTIOCGPLIST Fa "struct dtioc_probe *dtpr" +Get available probe entries. +.Bd -literal +struct dtioc_probe { + size_t dtpr_size; + struct dtioc_probe_info *dtpr_probes; +}; +.Ed +.Pp +If +.Va dtpr_size +is non-zero, as many probes as possible that can fit into this size +will be copied into the supplied buffer. +On exit, +.Va dtpr_size +is always set to the total size required to hold all probe entries +(i.e., it is set to +.Li sizeof(struct dtioc_probe_info) * dt_nprobes ) . +.It Dv DTIOCGSTATS Fa "struct dtioc_stat *dtst" +Get statistics for current recording. +.Bd -literal +struct dtioc_stat { + uint64_t dtst_readevt; + uint64_t dtst_dropevt; +}; +.Ed +.It Dv DTIOCRECORD Fa "int on" +Start or stop recording. +.It Dv DTIOCPRBENABLE Fa "struct dtioc_req *dtrq" +Enable the given probe for recording. +.Bd -literal +struct dtioc_req { + uint32_t dtrq_pbn; + struct dt_filter dtrq_filter; + uint32_t dtrq_rate; + uint64_t dtrq_evtflags; +}; +.Ed +.El .Sh FILES .Bl -tag -width /dev/dt -compact .It Pa /dev/dt dynamic tracing device. .El +.Sh ERRORS +An open of +.Pa /dev/dt +will fail if: +.Bl -tag -width Er +.It Bq Er EPERM +the +.Va kern.allowdt +.Xr sysctl 2 +variable wasn't set. +.It Bq Er ENOMEM +not enough memory space was available. +.El .Sh SEE ALSO .Xr ioctl 2 .\".Xr bt 5 , |