It turns out that truss also used kdump's mkioctls script, and expected

ioctlname() to return a pointer to the name rather than print it.  This did
not show up in testing because truss had its own prototype for ioctlname(),
so it would build fine and run fine as long as the program being traced did
not issue an ioctl.

Teach mkioctls to generate different versions of ioctlname() based on its
first command-line argument.

Pointed out by:	Garrett Cooper <yanegomi@gmail.com>

usr.bin/kdump/Makefile

@@ -22,7 +22,7 @@ CLEANFILES=	ioctl.c kdump_subr.c kdump_subr.h linux_syscalls.c
 
 ioctl.c: mkioctls
 	env MACHINE=${MACHINE} \
-	    sh ${.CURDIR}/mkioctls ${DESTDIR}/usr/include > ${.TARGET}
+	    sh ${.CURDIR}/mkioctls print ${DESTDIR}/usr/include > ${.TARGET}
 
 kdump_subr.h: mksubr
 	sh ${.CURDIR}/mksubr ${DESTDIR}/usr/include | \

usr.bin/kdump/mkioctls

@@ -1,20 +1,26 @@
 #!/bin/sh
 #
 # $FreeBSD$
+#
+# When editing this script, keep in mind that truss also uses it.
+#
 
 set -e
 
-if [ -z "$1" ]; then
-	echo "usage: sh $0 include-dir"
+if [ $# -ne 2 -o \( $1 != "print" -a $1 != "return" \) ]; then
+	echo "usage: sh $0 print|return include-dir"
 	exit 1
 fi
 
+style="$1"
+includedir="$2"
+
 LC_ALL=C; export LC_ALL
 
 # Build a list of headers that have ioctls in them.
 # XXX should we use an ANSI cpp?
 ioctl_includes=$(
-	cd $1
+	cd $includedir
 	find -H -s * -name '*.h' | grep -v '.*disk.*\.h' | \
 		xargs egrep -l \
 '^#[ 	]*define[ 	]+[A-Za-z_][A-Za-z0-9_]*[ 	]+_IO[^a-z0-9_]' |
@@ -33,7 +39,7 @@ esac
 
 awk -v x="$ioctl_includes" 'BEGIN {print x}' |
 	gcc -E -I$1 -dM -DCOMPAT_43TTY - |
-	awk -v ioctl_includes="$ioctl_includes" '
+	awk -v ioctl_includes="$ioctl_includes" -v style="$style" '
 BEGIN {
 	print "/* XXX obnoxious prerequisites. */"
 	print "#define COMPAT_43"
@@ -58,12 +64,19 @@ BEGIN {
 	print "#include <stdio.h>"
 	print "#include <cam/cam.h>"
 	print ""
-	print "void ioctlname(unsigned long val, int decimal);"
-	print ""
 	print ioctl_includes
 	print ""
-	print "void"
-	print "ioctlname(unsigned long val, int decimal)"
+	if (style == "print") {
+		print "void ioctlname(unsigned long val, int decimal);"
+		print ""
+		print "void"
+		print "ioctlname(unsigned long val, int decimal)"
+	} else {
+		print "const char *ioctlname(unsigned long val);"
+		print ""
+		print "const char *"
+		print "ioctlname(unsigned long val)"
+	}
 	print "{"
 	print "\tconst char *str = NULL;"
 	print ""
@@ -77,20 +90,24 @@ BEGIN {
 			break;
 	++i;
 	#
-	print("\t");
+	printf("\t");
 	if (n++ > 0)
-		print("else ");
+		printf("else ");
 	printf("if (val == %s)\n", $i);
 	printf("\t\tstr = \"%s\";\n", $i);
 }
 END {
-	print "\n"
-	print "\tif (str != NULL)\n"
-	print "\t\tprintf(\"%s\", str);\n"
-	print "\telse if (decimal)\n"
-	print "\t\tprintf(\"%lu\", val);\n"
-	print "\telse\n"
-	print "\t\tprintf(\"%#lx\", val);\n"
+	print ""
+	if (style == "print") {
+		print "\tif (str != NULL)"
+		print "\t\tprintf(\"%s\", str);"
+		print "\telse if (decimal)"
+		print "\t\tprintf(\"%lu\", val);"
+		print "\telse"
+		print "\t\tprintf(\"%#lx\", val);"
+	} else {
+		print "\treturn (str);"
+	}
 	print "}"
 }
 '

usr.bin/truss/Makefile

@@ -23,7 +23,8 @@ syscalls.h:	syscalls.master
 		${.CURDIR}/i386.conf
 
 ioctl.c: ${.CURDIR}/../kdump/mkioctls
-	sh ${.CURDIR}/../kdump/mkioctls ${DESTDIR}/usr/include > ${.TARGET}
+	env MACHINE=${MACHINE} \
+		/bin/sh ${.CURDIR}/../kdump/mkioctls return ${DESTDIR}/usr/include > ${.TARGET}
 
 .if ${MACHINE_CPUARCH} == "i386"
 SRCS+=	i386-linux.c linux_syscalls.h

usr.bin/truss/extern.h

@@ -35,7 +35,7 @@ extern int setup_and_wait(char **);
 extern int start_tracing(int);
 extern void restore_proc(int);
 extern void waitevent(struct trussinfo *);
-extern const char *ioctlname(register_t val);
+extern const char *ioctlname(unsigned long val);
 extern char *strsig(int sig);
 #ifdef __amd64__
 extern void amd64_syscall_entry(struct trussinfo *, int);