xref: /freebsd/share/man/man9/SYSCALL_MODULE.9 (revision a7623790fb345e6dc986dfd31df0ace115e6f2e4)
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29.\" $FreeBSD$
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31.Dd January 24, 2015
32.Dt SYSCALL_MODULE 9
33.Os
34.Sh NAME
35.Nm SYSCALL_MODULE
36.Nd syscall kernel module declaration macro
37.Sh SYNOPSIS
38.In sys/param.h
39.In sys/kernel.h
40.In sys/proc.h
41.In sys/module.h
42.In sys/sysent.h
43.Fn SYSCALL_MODULE name "int *offset" "struct sysent *new_sysent" "modeventhand_t evh" "void *arg"
44.Sh DESCRIPTION
45The
46.Fn SYSCALL_MODULE
47macro declares a new syscall.
48.Fn SYSCALL_MODULE
49expands into a kernel module declaration with name
50.Ql sys/ Ns Fa name .
51.Pp
52The rest of the arguments expected by this macro are:
53.Bl -tag -width ".Fa new_sysent"
54.It Fa offset
55A pointer to an
56.Vt int
57which saves the offset in
58.Vt "struct sysent"
59where the syscall is allocated.
60If the location pointed to by
61.Fa offset
62holds a non 0 number it will be used if possible.
63If it holds 0 then one will be assigned.
64.It Fa new_sysent
65is a pointer to a structure that specifies the function implementing
66the syscall and the number of arguments this function needs (see
67.In sys/sysent.h ) .
68.It Fa evh
69A pointer to the kernel module event handler function with the argument
70.Fa arg .
71Please refer to
72.Xr module 9
73for more information.
74.It Fa arg
75The argument passed to the callback functions of the
76.Fa evh
77event handler when it is called.
78.El
79.Pp
80The syscall number assigned to the module can be retrieved using the
81.Xr modstat 3
82and
83.Xr modfind 3
84library functions in libc.
85The MACRO
86.Fn SYSCALL_MODULE_HELPER
87includes
88.Fn SYSCALL_MODULE
89and much of its boilerplate code.
90.Sh EXAMPLES
91A minimal example for a syscall module can be found in
92.Pa /usr/share/examples/kld/syscall/module/syscall.c .
93.Sh SEE ALSO
94.Xr module 9
95.Pp
96.Pa /usr/share/examples/kld/syscall/module/syscall.c
97.Sh AUTHORS
98This manual page was written by
99.An Alexander Langer Aq Mt alex@FreeBSD.org .
100