clang-analyzer: adding clang static analysis support

clang static analyzer is a source code analysis tool that
finds bugs in C, C++.

This patch automates clang analyzes part by integrating
it with 'make clang-check'

clang-checker.sh: runs clang analyzer with and without the
HEAD commit, and shows the bugs introduced by HEAD commit (if any)

sample report:

$[ glusterfs ]: make clang-check

================ Clang analyzer in progress ================
...

BASELINE BUGS LIST (before applying patch):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Out of bound array access --> 3
Memory leak --> 1
Unix API --> 24
Dead increment --> 5
Dereference of null pointer --> 1995
Uninitialized argument value --> 2
All Bugs --> 2872
Called function pointer is null null dereference --> 4
Dead initialization --> 49
Dead assignment --> 691
Undefined allocation of 0 bytes CERT MEM0 C CWE --> 5
Argument with nonnull attribute passed null --> 84
Result of operation is garbage or undefined --> 9

TARGET BUGS LIST (after applying patch):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Out of bound array access --> 3
Memory leak --> 1
Unix API --> 24
Dead increment --> 5
Dereference of null pointer --> 1995
Uninitialized argument value --> 2
All Bugs --> 2875
Called function pointer is null null
dereference --> 4
Dead initialization --> 49
Dead assignment --> 694
Undefined allocation of 0 bytes CERT MEM0 C CWE --> 5
Argument with nonnull attribute passed null --> 84
Result of operation is garbage or undefined --> 9

SUMMARY OF CLANG-ANALYZER:
~~~~~~~~~~~~~~~~~~~~~~~~~~
Extra 3 Bug[s] Introduced in: Dead assignment

Patch Value given by Clang analyzer '-1'

Explore complete results at
/home/user/work/glusterfs/baseline/results/index.html
/home/user/work/glusterfs/target/results/index.html

================= Done with Clang Analysis =================

Change-Id: I512e33cfc02885a111152fbc1832144261dda1da
BUG: 1228142
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
Reviewed-on: http://review.gluster.org/11083
Tested-by: Prasanna Kumar Kalever <pkalever@redhat.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Smoke: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra Talur <rtalur@redhat.com>
Reviewed-by: Kaleb KEITHLEY <kkeithle@redhat.com>

3 files changed, 306 insertions, 2 deletions

diff --git a/Makefile.am b/Makefile.am
index d36f53055ea..180f149e328 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -47,7 +47,10 @@ dist-hook: gen-VERSION gen-ChangeLog
 	-cp -f $(top_srcdir)/build-aux/config.sub.dist $(distdir)/config.sub
 	-cp -f $(top_srcdir)/build-aux/config.guess.dist $(distdir)/config.guess
 
-.PHONY: gen-VERSION gen-ChangeLog
+.PHONY: gen-VERSION gen-ChangeLog clang-check
+
+clang-check:
+	@$(top_srcdir)/extras/clang-checker.sh
 
 gen-ChangeLog:
 	(cd $(srcdir) && git diff && echo ===== git log ==== && git log) > $(distdir)/ChangeLog
diff --git a/extras/Makefile.am b/extras/Makefile.am
index 609d497f5b8..91c25c65fe6 100644
--- a/extras/Makefile.am
+++ b/extras/Makefile.am
@@ -22,7 +22,7 @@ EXTRA_DIST = $(conf_DATA) specgen.scm glusterfs-mode.el glusterfs.vim \
 	disk_usage_sync.sh clear_xattrs.sh glusterd-sysconfig glusterd.vol \
 	post-upgrade-script-for-quota.sh pre-upgrade-script-for-quota.sh \
 	command-completion/gluster.bash command-completion/Makefile \
-	command-completion/README stop-all-gluster-processes.sh
+	command-completion/README stop-all-gluster-processes.sh clang-checker.sh
 
 install-data-local:
 	if [ -n "$(tmpfilesdir)" ]; then \
diff --git a/extras/clang-checker.sh b/extras/clang-checker.sh
new file mode 100755
index 00000000000..4909d3adfcd
--- /dev/null
+++ b/extras/clang-checker.sh
@@ -0,0 +1,301 @@
+#!/usr/bin/env bash
+#*******************************************************************************
+#                                                                              *
+#  Copyright (c) 2016 Red Hat, Inc. <http://www.redhat.com>                    *
+#  This file is part of GlusterFS.                                             *
+#                                                                              *
+#  This file is licensed to you under your choice of the GNU Lesser            *
+#  General Public License, version 3 or any later version (LGPLv3 or           *
+#  later), or the GNU General Public License, version 2 (GPLv2), in all        *
+#  cases as published by the Free Software Foundation.                         *
+#------------------------------------------------------------------------------*
+#                                                                              *
+# clang-checker.sh:  This script runs clang static analyzer using 'scan-build' *
+#                    a perl wrapper. After you commit your patch i.e. right    *
+#                    before executing rfc.sh in order to push the patch to     *
+#                    repository, it is recommended that you execute            *
+#                    clang-checker.sh to perform static analysis inorder to    *
+#                    check if there are any possible bugs in the code.         *
+#                                                                              *
+#                    This script performs the static analysis with and      *
+#                    without HEAD commit, it runs the analyzer only in the     *
+#                    directory where changes have been made and finally diff's *
+#                    the number of bugs using both cases (i.e. with and        *
+#                    without your commit) and gives a summary, which explain's *
+#                    about the eligibility of your patch.                      *
+#                                                                              *
+# Usage:             $ cd $PATH_TO_GLUSTERFS                                   *
+#                    $ extras/clang-checker.sh (or) $ make clang-check         *
+#                                                                              *
+# Author:            Prasanna Kumar Kalever <prasanna.kalever@redhat.com>      *
+#                                                                              *
+#*******************************************************************************
+
+REPORTS_DIR=$(pwd)
+BASELINE_DIR=${REPORTS_DIR}/baseline
+BRESULTS_DIR=${BASELINE_DIR}/results
+BBACKUP_DIR=${BASELINE_DIR}/backup
+TARGET_DIR=${REPORTS_DIR}/target
+TRESULTS_DIR=${TARGET_DIR}/results
+TBACKUP_DIR=${TARGET_DIR}/backup
+
+declare -A DICT_B
+declare -A DICT_T
+declare -A ARR
+declare -A FILES
+
+function identify_changes () {
+    MODIFIED_DATA=$(git show --name-status --oneline | tail -n +2)
+    FLAG=0
+    for i in ${MODIFIED_DATA}; do
+        if [ $FLAG -eq 1 ]; then
+            ARR+="$(dirname $i) ";
+            FLAG=0;
+        fi
+        if [ $i = 'M' ] || [ $i = 'A' ]; then
+            FLAG=1;
+        fi
+    done
+
+    MODIFIED_DIR=$(echo "${ARR[@]}" | tr ' ' '\n' | sort -u | tr '\n' ' ')
+    for i in $MODIFIED_DIR; do
+        # run only in directories which has Makefile
+        if [ $(find ./$i -iname "makefile*" | wc -c) -gt 0 ]; then
+            # skip 'doc' and '.'(top) directory
+            if [ "xx$i" != "xxdoc" ] && [ "xx$i" != "xx." ]; then
+                FILES+="$i "
+            fi
+        fi
+    done
+    if [ -z $FILES ]; then
+        echo "Probably no changes made to 'c' files"
+        exit;
+    fi
+}
+
+function check_prerequisites () {
+    if ! type "clang" 2> /dev/null; then
+        echo -e "\ntry after installing clang and scan-build..."
+        echo    "useful info at http://clang-analyzer.llvm.org/installation.html\n"
+        echo -e "hint: 'dnf -y install clang-analyzer.noarch'\n"
+        exit 1;
+    elif ! type "scan-build" 2> /dev/null; then
+        echo -e "\ntry after installing scan-build..."
+        echo    "useful info at http://clang-analyzer.llvm.org/installation.html"
+        echo -e "hint: 'dnf -y install clang-analyzer.noarch'\n"
+        exit 1;
+    fi
+}
+
+function force_terminate () {
+    echo -e "\nreceived a signal to force terminate ..\n"
+    git am --abort 2> /dev/null
+    git am ${PATCH_NAME}
+    rm -f ${REPORTS_DIR}/${PATCH_NAME}
+    exit 1;
+}
+
+function run_scanbuild () {
+    local CLANG=$(which clang)
+    local SCAN_BUILD=$(which scan-build)
+    local ORIG_COMMIT=$(git rev-parse --verify HEAD^)
+    PATCH_NAME=$(git format-patch $ORIG_COMMIT)
+
+    echo -e "\n| Performing clang analysis on:" \
+            "$(git log --pretty=format:"%h - '%s' by %an" -1) ... |\n"
+    echo -e "Changes are identified in '${FILES[@]}' directorie[s]\n"
+
+    if [ -d "${BRESULTS_DIR}" ]; then
+        mkdir -p ${BBACKUP_DIR} ${TBACKUP_DIR}
+        mv ${BRESULTS_DIR} \
+           ${BBACKUP_DIR}/results_$(ls -l ${BBACKUP_DIR} | wc -l)
+        mv ${TRESULTS_DIR} \
+           ${TBACKUP_DIR}/results_$(ls -l ${TBACKUP_DIR} | wc -l)
+    fi
+    for DIR in ${FILES[@]}; do
+        mkdir -p ${BRESULTS_DIR}/$(echo ${DIR} | sed 's/\//_/g')
+        mkdir -p ${TRESULTS_DIR}/$(echo ${DIR} | sed 's/\//_/g')
+    done
+    # get nproc info
+    case $(uname -s) in
+    'Linux')
+        local NPROC=$(getconf _NPROCESSORS_ONLN)
+        ;;
+    'NetBSD')
+        local NPROC=$(getconf NPROCESSORS_ONLN)
+        ;;
+    esac
+
+    trap force_terminate INT TERM QUIT EXIT
+
+    git reset --hard HEAD^
+
+    # build complete source code for sake of dependencies
+    echo -e "\n# make -j${NPROC} ..."
+    make -j${NPROC} 1>/dev/null
+
+    for DIR in ${FILES[@]}; do
+        if [ $(find ./$i -iname "makefile*" | wc -c) -gt 0 ]; then
+            make clean -C ${DIR} 1>/dev/null
+            echo -e "\n| Analyzing ${DIR} without commit ... |\n"
+            # run only in directory where changes are made
+            ${SCAN_BUILD} -o ${BRESULTS_DIR}/$(echo ${DIR} | sed 's/\//_/g') \
+                          --use-analyzer=${CLANG} make -j${NPROC} -C ${DIR}
+        fi
+    done
+
+    echo -e "\n| Analyzing without commit complete ... |\n"
+
+    git am ${PATCH_NAME}
+    trap - INT TERM QUIT EXIT
+
+    # In case commit has changes to configure stuff ?
+    echo -e "\n# make clean ..."
+    make clean 1>/dev/null
+    echo -e "\n# ./autogen.sh && ./configure --with-previous-options ..."
+    ${REPORTS_DIR}/autogen.sh 2>/dev/null
+    ${REPORTS_DIR}/configure  --with-previous-options 1>/dev/null
+    echo -e "\n# make -j${NPROC} ..."
+    make -j${NPROC} 1>/dev/null
+
+    for DIR in ${FILES[@]}; do
+        if [ $(find ./$i -iname "makefile*" | wc -c) -gt 0 ]; then
+            make clean -C ${DIR} 1>/dev/null
+            echo -e "\n| Analyzing ${DIR} with commit ... |\n"
+            # run only in directory where changes are made
+            ${SCAN_BUILD} -o ${TRESULTS_DIR}/$(echo ${DIR} | sed 's/\//_/g') \
+                          --use-analyzer=${CLANG} make -j${NPROC} -C ${DIR}
+        fi
+    done
+
+    echo -e "\n| Analyzing with commit complete ... |\n"
+
+    rm -f ${REPORTS_DIR}/${PATCH_NAME}
+}
+
+function count_for_baseline () {
+    for DIR in ${FILES[@]}; do
+        HTMLS_DIR=${BRESULTS_DIR}/$(echo ${DIR} |
+                    sed 's/\//_/g')/$(ls ${BRESULTS_DIR}/$(echo ${DIR} |
+                    sed 's/\//_/g')/);
+
+        local NAMES_OF_BUGS_B=$(grep -n "SUMM_DESC" ${HTMLS_DIR}/index.html |
+                                cut -d"<" -f3 | cut -d">" -f2 |
+                                sed 's/[^a-zA-Z0]/_/g' | tr '\n' ' ')
+        local NO_OF_BUGS_B=$(grep -n "SUMM_DESC" ${HTMLS_DIR}/index.html |
+                             cut -d"<" -f5 | cut -d">" -f2 | tr '\n' ' ')
+        local count_B=0;
+
+        read -a BUG_NAME_B <<<$NAMES_OF_BUGS_B
+        read -a BUG_COUNT_B <<<$NO_OF_BUGS_B
+        for i in ${BUG_NAME_B[@]};
+        do
+            if [ ! -z ${DICT_B[$i]} ]; then
+                DICT_B[$i]=$(expr ${BUG_COUNT_B[count_B]} + ${DICT_B[$i]});
+            else
+                DICT_B+=([$i]=${BUG_COUNT_B[count_B]});
+            fi
+            count_B=$(expr $count_B + 1)
+        done
+    done
+
+    echo -e "\nBASELINE BUGS LIST (before applying patch):"
+    echo "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"
+    for key_B in ${!DICT_B[@]}; do
+        echo "${key_B} --> ${DICT_B[${key_B}]}" | sed 's/_/ /g' | tr -s ' '
+    done
+}
+
+function count_for_target () {
+    for DIR in ${FILES[@]}; do
+        HTMLS_DIR=${TRESULTS_DIR}/$(echo ${DIR} |
+                    sed 's/\//_/g')/$(ls ${TRESULTS_DIR}/$(echo ${DIR} |
+                    sed 's/\//_/g')/);
+
+        local NAME_OF_BUGS_T=$(grep -n "SUMM_DESC" ${HTMLS_DIR}/index.html |
+                              cut -d"<" -f3 | cut -d">" -f2 |
+                              sed 's/[^a-zA-Z0]/_/g'| tr '\n' ' ')
+        local NO_OF_BUGS_T=$(grep -n "SUMM_DESC" ${HTMLS_DIR}/index.html |
+                             cut -d"<" -f5 | cut -d">" -f2 | tr '\n' ' ')
+        local count_T=0;
+
+        read -a BUG_NAME_T <<<$NAME_OF_BUGS_T
+        read -a BUG_COUNT_T <<<$NO_OF_BUGS_T
+
+        for i in ${BUG_NAME_T[@]};
+        do
+            if [ ! -z ${DICT_T[$i]} ]; then
+                DICT_T[$i]=$(expr ${BUG_COUNT_T[count_T]} + ${DICT_T[$i]});
+            else
+                DICT_T+=([$i]=${BUG_COUNT_T[count_T]});
+            fi
+            count_T=$(expr $count_T + 1)
+        done
+    done
+
+    echo -e "\nTARGET BUGS LIST (after applying patch):"
+    echo "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~"
+    for key_T in ${!DICT_T[@]}; do
+        echo "${key_T} --> ${DICT_T[${key_T}]}" | sed 's/_/ /g' | tr -s ' '
+    done
+}
+
+function array_contains () {
+    local SEEKING=$1; shift
+    local IN=1
+    for ELEMENT; do
+        if [[ $ELEMENT == $SEEKING ]]; then
+            IN=0
+            break
+        fi
+    done
+    return $IN
+}
+
+function main () {
+    echo -e "\n================ Clang analyzer in progress ================\n"
+    check_prerequisites
+    identify_changes
+    run_scanbuild
+    clear
+    count_for_baseline
+    count_for_target
+    echo -e "\nSUMMARY OF CLANG-ANALYZER:"
+    echo "~~~~~~~~~~~~~~~~~~~~~~~~~~"
+
+    FLAG=0
+    for BUG in ${!DICT_T[@]}; do
+        array_contains $BUG "${!DICT_B[@]}"
+        if [ $? -eq 1 ]; then
+            echo "New ${DICT_T[${BUG}]} Bug[s] introduced: $(echo $BUG |
+                                                            sed 's/_/ /g' |
+                                                            tr -s ' ')"
+            FLAG=1
+        else
+            if [ ${BUG} != "All_Bugs" ]; then
+                if [ ${DICT_B[${BUG}]} -lt            \
+                    ${DICT_T[${BUG}]} ]; then
+                    echo "Extra $(expr ${DICT_T[${BUG}]} - \
+                          ${DICT_B[${BUG}]}) Bug[s] Introduced in: $(echo $BUG |
+                          sed 's/_/ /g' | tr -s ' ')"
+                    FLAG=1
+                fi
+            fi
+        fi
+    done
+
+    echo
+    if [ $FLAG -eq 0 ]; then
+        echo -e "Patch Value given by Clang analyzer '+1'\n"
+    else
+        echo -e "Patch Value given by Clang analyzer '-1'\n"
+    fi
+    echo -e "\nExplore complete results at:"
+    find ${BRESULTS_DIR}/ -iname "index.html"
+    find ${TRESULTS_DIR}/ -iname "index.html"
+    echo -e "\n================= Done with Clang Analysis =================\n"
+
+    exit ${FLAG}
+}
+
+main