.\" Copyright (c) 2018 Mariusz Zaborski <oshogbo@FreeBSD.org>
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.Dd May 5, 2020
.Dt CAP_SYSLOG 3
.Os
.Sh NAME
.Nm cap_syslog
.Nm cap_vsyslog
.Nm cap_openlog
.Nm cap_closelog
.Nm cap_setlogmask
.Nd "library for syslog in capability mode"
.Sh LIBRARY
.Lb libcap_syslog
.Sh SYNOPSIS
.In libcasper.h
.In casper/cap_syslog.h
.Ft void
.Fn cap_syslog "cap_channel_t *chan" "int pri" "const char *fmt" "..."
.Ft void
.Fn cap_vsyslog "cap_channel_t *chan" "int priority" "const char *fmt" "va_list ap"
.Ft void
.Fn cap_openlog "cap_channel_t *chan" "const char *ident" "int logopt" "int facility"
.Ft void
.Fn cap_closelog "cap_channel_t *chan"
.Ft int
.Fn cap_setlogmask "cap_channel_t *chan" "int maskpri"
.Sh DESCRIPTION
The functions
.Fn cap_syslog
.Fn cap_vsyslog
.Fn cap_openlog
.Fn cap_closelog
.Fn cap_setlogmask
are respectively equivalent to
.Xr syslog 3 ,
.Xr vsyslog 3 ,
.Xr openlog 3 ,
.Xr closelog 3 ,
.Xr setlogmask 3
except that the connection to the
.Nm system.syslog
service needs to be provided.
.Sh EXAMPLES
The following example first opens a capability to casper and then uses this
capability to create the
.Nm system.syslog
casper service to log messages.
.Bd -literal
cap_channel_t *capcas, *capsyslog;

/* Open capability to Casper. */
capcas = cap_init();
if (capcas == NULL)
	err(1, "Unable to contact Casper");

/* Enter capability mode sandbox. */
if (cap_enter() < 0 && errno != ENOSYS)
	err(1, "Unable to enter capability mode");

/* Use Casper capability to create capability to the system.syslog service. */
capsyslog = cap_service_open(capcas, "system.syslog");
if (capsyslog == NULL)
	err(1, "Unable to open system.syslog service");

/* Close Casper capability, we don't need it anymore. */
cap_close(capcas);

/* Let's log something. */
cap_syslog(capsyslog, LOG_NOTICE, "System logs from capability mode.");
.Ed
.Sh SEE ALSO
.Xr cap_enter 2 ,
.Xr closelog 3 ,
.Xr err 3 ,
.Xr openlog 3 ,
.Xr setlogmask 3
.Xr syslog 3 ,
.Xr vsyslog 3 ,
.Xr capsicum 4 ,
.Xr nv 9
.Sh HISTORY
The
.Nm cap_syslog
service first appeared in
.Fx 10.3 .
.Sh AUTHORS
.An Mariusz Zaborski Aq Mt oshogbo@FreeBSD.org