[PATCH 02/19] perf jvmti: improve error message in Makefile

From: Arnaldo Carvalho de Melo
Date: Fri Feb 26 2016 - 18:23:09 EST

From: Stephane Eranian <eranian@xxxxxxxxxx>

This patch improves the error message given by jvmti Makefile when the
alternatives command cannot be found. It now suggests the user locates
the root of their Java installation and pass it with JDIR=

Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1456378056-18812-1-git-send-email-eranian@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
tools/perf/jvmti/Makefile | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/tools/perf/jvmti/Makefile b/tools/perf/jvmti/Makefile
index 0277a64b391b..5ce61a1bda9c 100644
--- a/tools/perf/jvmti/Makefile
+++ b/tools/perf/jvmti/Makefile
@@ -35,12 +35,21 @@ SOLIBEXT=so

# The following works at least on fedora 23, you may need the next
# line for other distros.
-ifeq (,$(wildcard /usr/sbin/update-java-alternatives))
-JDIR=$(shell alternatives --display java | tail -1 | cut -d' ' -f 5 | sed 's%/jre/bin/java.%%g')
+ifneq (,$(wildcard /usr/sbin/update-java-alternatives))
JDIR=$(shell /usr/sbin/update-java-alternatives -l | head -1 | cut -d ' ' -f 3)
+ ifneq (,$(wildcard /usr/sbin/alternatives))
+ JDIR=$(shell alternatives --display java | tail -1 | cut -d' ' -f 5 | sed 's%/jre/bin/java.%%g')
+ endif
+ifndef JDIR
+$(error Could not find alternatives command, you need to set JDIR= to point to the root of your Java directory)
+ ifeq (,$(wildcard $(JDIR)/include/jvmti.h))
+ $(error the openjdk development package appears to me missing, install and try again)
+ endif
+$(info Using Java from $(JDIR))
# -lrt required in 32-bit mode for clock_gettime()
LIBS=-lelf -lrt
INCDIR=-I $(JDIR)/include -I $(JDIR)/include/linux