.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.\" Copyright (c) 2026 Mateusz Piotrowski <0mp@FreeBSD.org>
.\"
.Dd May 7, 2026
.Dt DTRACE_SYSCALL 4
.Os
.Sh NAME
.Nm dtrace_syscall
.Nd a DTrace provider for system calls
.Sh SYNOPSIS
.Nm syscall Ns Cm \&: Ns Ar abi Ns Cm \&: Ns Ar syscall Ns Cm :entry
.Nm syscall Ns Cm \&: Ns Ar abi Ns Cm \&: Ns Ar syscall Ns Cm :return
.Sh DESCRIPTION
The
.Nm syscall
provider provides entry and return probes for system calls.
.Pp
The module in the probe's description is
.Ar abi ,
which indicates what system call ABI a
.Ar syscall
belongs to.
.Nm
supports the following system call ABIs:
.Pp
.Bl -tag -offset indent -width freebsd32 -compact
.It Cm freebsd
Native ABI.
.It Cm freebsd32
Non-native, 32-bit ABI.
.It Cm linux
Refer to
.Xr linux 4 .
.It Cm linux32
Refer to
.Xr linux 4 .
.El
.Pp
The arguments to the
.Cm entry
probes are the arguments passed to the system call.
.Pp
The
.Cm return
probe stores the system call's return value in both
.Fa arg0
and
.Fa arg1 .
.Pp
Inspect the
.Xr d 7 Ap s
.Va errno
variable to check if a system call failed.
.Sh EXAMPLES
.Ss Example 1 : Count Up System Calls
The following script traces all system calls and counts them for every process
on the system.
.Bd -literal -offset 2n
syscall:::entry {
    @[execname, pid] = count();
}
.Ed
.Sh SEE ALSO
.Xr dtrace 1 ,
.Xr intro 2 ,
.Xr tracing 7
.Rs
.%B The illumos Dynamic Tracing Guide
.%O Chapter syscall Provider
.%D 2008
.%U https://illumos.org/books/dtrace/chp-syscall.html
.Re
.Rs
.%A Brendan Gregg
.%A Jim Mauro
.%B DTrace: Dynamic Tracing in Oracle Solaris, Mac OS X and FreeBSD
.%I Prentice Hall
.%O Chapter Syscall Provider
.%P pp. 315\(en327
.%D 2011
.%U https://www.brendangregg.com/dtracebook/
.Re
.Sh AUTHORS
This manual page was written by
.An Mateusz Piotrowski Aq Mt 0mp@FreeBSD.org .