Add a new GDB_LIBEXEC option to install gdb and kgdb to /usr/libexec.

When this option is enabled, only gdb and kgdb are installed to
/usr/libexec for use by crashinfo(8). Other bits of GDB such as
gdbserver and gdbtui are not installed. For this option to be
effective, GDB must be enabled.

Rework r317094 to re-enable GDB on all platforms but enable
GDB_LIBEXEC on platforms for which the GDB in ports is a superset of
functionality.

Reviewed by:	emaste, kib
Suggested by:	kib
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D10449

gnu/usr.bin/gdb/Makefile

@@ -1,9 +1,15 @@
 # $FreeBSD$
 
-SUBDIR=	libgdb gdb gdbtui kgdb
+.include <src.opts.mk>
+
+SUBDIR=	libgdb gdb kgdb
+
+.if ${MK_GDB_LIBEXEC} == "no"
+SUBDIR+= gdbtui
 
 .if exists(${.CURDIR}/gdbserver/reg-${MACHINE_CPUARCH}.c)
 SUBDIR+=gdbserver
 .endif
+.endif
 
 .include <bsd.subdir.mk>

gnu/usr.bin/gdb/Makefile.inc

@@ -1,5 +1,7 @@
 # $FreeBSD$
 
+.include <src.opts.mk>
+
 VERSION= "6.1.1 [FreeBSD]"
 VENDOR= marcel
 
@@ -53,6 +55,9 @@ GENSRCS+= nm.h tm.h
 CFLAGS+= -DCROSS_DEBUGGER -I${BMAKE_ROOT:H:H}
 GDB_SUFFIX= -${TARGET_ARCH}
 MAN=
+.elif ${MK_GDB_LIBEXEC} != "no"
+BINDIR?=	/usr/libexec
+MAN=
 .endif
 
 .include "${TARGET_SUBDIR}/Makefile"

share/mk/src.opts.mk

@@ -97,6 +97,7 @@ __DEFAULT_YES_OPTIONS = \
     FTP \
     GAMES \
     GCOV \
+    GDB \
     GNU_DIFF \
     GNU_GREP \
     GPIO \
@@ -267,9 +268,9 @@ BROKEN_OPTIONS+=LLDB
 # does not yet contain kernel support for arm, and sparc64 kernel support
 # has not been tested.
 .if ${__T:Marm*} != "" || ${__T} == "sparc64"
-__DEFAULT_YES_OPTIONS+=GDB
+__DEFAULT_NO_OPTIONS+=GDB_LIBEXEC
 .else
-__DEFAULT_NO_OPTIONS+=GDB
+__DEFAULT_YES_OPTIONS+=GDB_LIBEXEC
 .endif
 # Only doing soft float API stuff on armv6
 .if ${__T} != "armv6"

tools/build/mk/OptionalObsoleteFiles.inc

@@ -2431,7 +2431,7 @@ OLD_FILES+=usr/bin/gcov
 OLD_FILES+=usr/share/man/man1/gcov.1.gz
 .endif
 
-.if ${MK_GDB} == no
+.if ${MK_GDB} == no || ${MK_GDB_LIBEXEC} == yes
 OLD_FILES+=usr/bin/gdb
 OLD_FILES+=usr/bin/gdbserver
 OLD_FILES+=usr/bin/gdbtui
@@ -2441,6 +2441,11 @@ OLD_FILES+=usr/share/man/man1/gdbserver.1.gz
 OLD_FILES+=usr/share/man/man1/kgdb.1.gz
 .endif
 
+.if ${MK_GDB} == no || ${MK_GDB_LIBEXEC} == no
+OLD_FILES+=usr/libexec/gdb
+OLD_FILES+=usr/libexec/kgdb
+.endif
+
 .if ${MK_GPIO} == no
 OLD_FILES+=usr/include/libgpio.h
 OLD_FILES+=usr/lib/libgpio.a

tools/build/options/WITHOUT_GDB_LIBEXEC

@@ -0,0 +1,5 @@
+.\" $FreeBSD$
+Set to install
+.Xr gdb 1
+into
+.Pa /usr/bin .

tools/build/options/WITH_GDB_LIBEXEC

@@ -0,0 +1,10 @@
+.\" $FreeBSD$
+Set to install
+.Xr gdb 1
+into
+.Pa /usr/libexec .
+This permits
+.Xr gdb 1
+to be used as a fallback for
+.Xr crashinfo 8
+if a newer version is not installed.

usr.sbin/crashinfo/crashinfo.sh

@@ -35,6 +35,19 @@ usage()
 	exit 1
 }
 
+# Find a gdb binary to use and save the value in GDB.
+find_gdb()
+{
+	local binary
+
+	for binary in /usr/local/bin/gdb /usr/libexec/gdb /usr/bin/gdb; do
+		if [ -x ${binary} ]; then
+			GDB=${binary}
+			return
+		fi
+	done
+}
+
 # Run a single gdb command against a kernel file in batch mode.
 # The kernel file is specified as the first argument and the command
 # is given in the remaining arguments.
@@ -44,10 +57,10 @@ gdb_command()
 
 	k=$1 ; shift
 
-	if [ -x /usr/local/bin/gdb ]; then
-		/usr/local/bin/gdb -batch -ex "$@" $k
+	if [ ${GDB} = /usr/local/bin/gdb ]; then
+		${GDB} -batch -ex "$@" $k
 	else
-		echo -e "$@" | /usr/bin/gdb -x /dev/stdin -batch $k
+		echo -e "$@" | ${GDB} -x /dev/stdin -batch $k
 	fi
 }
 
@@ -140,6 +153,12 @@ INFO=$CRASHDIR/info.$DUMPNR
 FILE=$CRASHDIR/core.txt.$DUMPNR
 HOSTNAME=`hostname`
 
+find_gdb
+if [ -z "$GDB" ]; then
+	echo "Unable to find a kernel debugger."
+	exit 1
+fi
+
 if [ ! -e $VMCORE ]; then
 	echo "$VMCORE not found"
 	exit 1
@@ -189,11 +208,7 @@ file=`mktemp /tmp/crashinfo.XXXXXX`
 if [ $? -eq 0 ]; then
 	echo "bt" >> $file
 	echo "quit" >> $file
-	if [ -x /usr/local/bin/kgdb ]; then
-		/usr/local/bin/kgdb $KERNEL $VMCORE < $file
-	else
-		kgdb $KERNEL $VMCORE < $file
-	fi
+	${GDB%gdb}kgdb $KERNEL $VMCORE < $file
 	rm -f $file
 	echo
 fi