xref: /freebsd/cddl/usr.sbin/dwatch/libexec/rw (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)

# -*- tab-width: 4 -*- ;; Emacs
# vi: set filetype=sh tabstop=8 shiftwidth=8 noexpandtab :: Vi/ViM
############################################################ IDENT(1)
#
# $Title: dwatch(8) module for read(2), write(2), or similar entry $
# $Copyright: 2014-2018 Devin Teske. All rights reserved. $
#
############################################################ DESCRIPTION
#
# Display data sent/received when read(2)/write(2) occurs
#
############################################################ PROBE

case "$PROFILE" in
rw) : ${PROBE:=syscall::read:entry, syscall::write:entry} ;;
 *) : ${PROBE:=syscall::$PROFILE:entry}
esac

############################################################ ACTIONS

exec 9<<EOF
this size_t nbytes;
this string bufstr;
this string flow;
this void * buf;
this void * data;

$PROBE /* probe ID $ID */
{${TRACE:+
	printf("<$ID>");
}
	/*
	 * R/W
	 */
	this->flow = probefunc == "read" ? "<-" : "->";
	this->buf = (void *)arg1;
	this->nbytes = (size_t)arg2;

	/*
	 * Allocate temporary memory for, copy, and NUL-terminate the data
	 */
	this->data = alloca(this->nbytes + 1);
	copyinto((uintptr_t)this->buf, this->nbytes, this->data);
	bcopy("\0", (void *)((uintptr_t)this->data + this->nbytes), 1);

	/*
	 * Extract string from temporary memory
	 */
	this->bufstr = stringof(this->data);
}
EOF
ACTIONS=$( cat <&9 )
ID=$(( $ID + 1 ))

############################################################ EVENT DETAILS

if [ ! "$CUSTOM_DETAILS" ]; then
exec 9<<EOF
	/*
	 * Print read/write details
	 */
	printf("%s \"%s\" %d byte%s",
		this->flow,
		this->bufstr,
		this->nbytes,
		this->nbytes == 1 ? "" : "s");
EOF
EVENT_DETAILS=$( cat <&9 )
fi

################################################################################
# END
################################################################################