devtools: alert on new calls to exit from libs

This patch adds a new function that is called
per every checked patch,
and alerts for new instances of rte_panic/rte_exit.
The check excludes comments, and alerts in the case
of a positive balance between additions and removals.

Signed-off-by: Arnon Warshavsky <arnon@qwilt.com>
Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
Tested-by: Kevin Traynor <ktraynor@redhat.com>

devtools/checkpatches.sh

@@ -43,6 +43,88 @@ print_usage () {
 	END_OF_HELP
 }
 
+check_forbidden_additions() {
+    # This awk script receives a list of expressions to monitor
+    # and a list of folders to search these expressions in
+    # - No search is done inside comments
+    # - Both additions and removals of the expressions are checked
+    #   A positive balance of additions fails the check
+	read -d '' awk_script << 'EOF'
+	BEGIN {
+		split(FOLDERS,deny_folders," ");
+		split(EXPRESSIONS,deny_expr," ");
+		in_file=0;
+		in_comment=0;
+		count=0;
+		comment_start="/*"
+		comment_end="*/"
+	}
+	# search for add/remove instances in current file
+	# state machine assumes the comments structure is enforced by
+	# checkpatches.pl
+	(in_file) {
+		# comment start
+		if (index($0,comment_start) > 0) {
+			in_comment = 1
+		}
+		# non comment code
+		if (in_comment == 0) {
+			for (i in deny_expr) {
+				forbidden_added = "^\+.*" deny_expr[i];
+				forbidden_removed="^-.*" deny_expr[i];
+				current = expressions[deny_expr[i]]
+				if ($0 ~ forbidden_added) {
+					count = count + 1;
+					expressions[deny_expr[i]] = current + 1
+				}
+				if ($0 ~ forbidden_removed) {
+					count = count - 1;
+					expressions[deny_expr[i]] = current - 1
+				}
+			}
+		}
+		# comment end
+		if (index($0,comment_end) > 0) {
+			in_comment = 0
+		}
+	}
+	# switch to next file , check if the balance of add/remove
+	# of previous filehad new additions
+	($0 ~ "^\+\+\+ b/") {
+		in_file = 0;
+		if (count > 0) {
+			exit;
+		}
+		for (i in deny_folders) {
+			re = "^\+\+\+ b/" deny_folders[i];
+			if ($0 ~ deny_folders[i]) {
+				in_file = 1
+				last_file = $0
+			}
+		}
+	}
+	END {
+		if (count > 0) {
+			print "Warning in " substr(last_file,6) ":"
+			print "are you sure you want to add the following:"
+			for (key in expressions) {
+				if (expressions[key] > 0) {
+					print key
+				}
+			}
+			exit RET_ON_FAIL
+		}
+	}
+EOF
+	# ---------------------------------
+	# refrain from new additions of rte_panic() and rte_exit()
+	# multiple folders and expressions are separated by spaces
+	awk -v FOLDERS="lib drivers" \
+		-v EXPRESSIONS="rte_panic\\\( rte_exit\\\(" \
+		-v RET_ON_FAIL=1 \
+		"$awk_script" -
+}
+
 number=0
 quiet=false
 verbose=false
@@ -97,6 +179,13 @@ check () { # <patch> <commit> <title>
 		ret=1
 	fi
 
+	! $verbose || printf '\nChecking forbidden tokens additions:\n'
+	report=$(check_forbidden_additions <"$tmpinput")
+	if [ $? -ne 0 ] ; then
+		printf '%s\n' "$report"
+		ret=1
+	fi
+
 	clean_tmp_files
 	[ $ret -eq 0 ] && return 0