From 9b43f1d5f4220f9bf0b1a167296ba2a8dd9f83f5 Mon Sep 17 00:00:00 2001
From: Jon Siwek <jsiwek@corelight.com>
Date: Thu, 24 Jan 2019 14:54:39 -0600
Subject: [PATCH] GH-167: improve error message for unclosed function at EOF

---
 src/parse.y                                   | 31 +++++++++++++------
 src/scan.l                                    |  9 +++++-
 .../language.eof-parse-errors/output1         |  1 +
 .../language.eof-parse-errors/output2         |  1 +
 testing/btest/language/eof-parse-errors.bro   | 21 +++++++++++++
 5 files changed, 52 insertions(+), 11 deletions(-)
 create mode 100644 testing/btest/Baseline/language.eof-parse-errors/output1
 create mode 100644 testing/btest/Baseline/language.eof-parse-errors/output2
 create mode 100644 testing/btest/language/eof-parse-errors.bro

diff --git a/src/parse.y b/src/parse.y
index a9f8d4b260..db7e0f846f 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -94,6 +94,9 @@
 #include <string>
 
 extern const char* filename;  // Absolute path of file currently being parsed.
+extern const char* last_filename; // Absolute path of last file parsed.
+extern const char* last_tok_filename;
+extern const char* last_last_tok_filename;
 
 YYLTYPE GetCurrentLocation();
 extern int yyerror(const char[]);
@@ -1723,19 +1726,27 @@ opt_deprecated:
 
 int yyerror(const char msg[])
 	{
-	char* msgbuf = new char[strlen(msg) + strlen(last_tok) + 128];
-
-	if ( last_tok[0] == '\n' )
-		sprintf(msgbuf, "%s, on previous line", msg);
-	else if ( last_tok[0] == '\0' )
-		sprintf(msgbuf, "%s, at end of file", msg);
-	else
-		sprintf(msgbuf, "%s, at or near \"%s\"", msg, last_tok);
-
 	if ( in_debug )
 		g_curr_debug_error = copy_string(msg);
 
-	reporter->Error("%s", msgbuf);
+	if ( last_tok[0] == '\n' )
+		reporter->Error("%s, on previous line", msg);
+	else if ( last_tok[0] == '\0' )
+		{
+		if ( last_filename )
+			reporter->Error("%s, at end of file %s", msg, last_filename);
+		else
+			reporter->Error("%s, at end of file", msg);
+		}
+	else
+		{
+		if ( last_last_tok_filename && last_tok_filename &&
+		     ! streq(last_last_tok_filename, last_tok_filename) )
+			reporter->Error("%s, at or near \"%s\" or end of file %s",
+			                msg, last_tok, last_last_tok_filename);
+		else
+			reporter->Error("%s, at or near \"%s\"", msg, last_tok);
+		}
 
 	return 0;
 	}
diff --git a/src/scan.l b/src/scan.l
index 763ee2d86d..c2be426044 100644
--- a/src/scan.l
+++ b/src/scan.l
@@ -43,11 +43,16 @@ int_list if_stack;
 
 int line_number = 1;
 const char* filename = 0; // Absolute path of file currently being parsed.
+const char* last_filename = 0; // Absolute path of last file parsed.
 static const char* last_id_tok = 0;
 
+const char* last_tok_filename = 0;
+const char* last_last_tok_filename = 0;
 char last_tok[128];
 
-#define YY_USER_ACTION	strncpy(last_tok, yytext, sizeof(last_tok) - 1);
+#define YY_USER_ACTION	strncpy(last_tok, yytext, sizeof(last_tok) - 1); \
+                        last_last_tok_filename = last_tok_filename; \
+                        last_tok_filename = ::filename;
 #define YY_USER_INIT	last_tok[0] = '\0';
 
 // We define our own YY_INPUT because we want to trap the case where
@@ -899,6 +904,8 @@ void add_to_name_list(char* s, char delim, name_list& nl)
 
 int yywrap()
 	{
+	last_filename = ::filename;
+
 	if ( reporter->Errors() > 0 )
 		return 1;
 
diff --git a/testing/btest/Baseline/language.eof-parse-errors/output1 b/testing/btest/Baseline/language.eof-parse-errors/output1
new file mode 100644
index 0000000000..47a1c328e3
--- /dev/null
+++ b/testing/btest/Baseline/language.eof-parse-errors/output1
@@ -0,0 +1 @@
+error: syntax error, at end of file ./a.bro
diff --git a/testing/btest/Baseline/language.eof-parse-errors/output2 b/testing/btest/Baseline/language.eof-parse-errors/output2
new file mode 100644
index 0000000000..6f382c2a12
--- /dev/null
+++ b/testing/btest/Baseline/language.eof-parse-errors/output2
@@ -0,0 +1 @@
+error in ./b.bro, line 1: syntax error, at or near "module" or end of file ./a.bro
diff --git a/testing/btest/language/eof-parse-errors.bro b/testing/btest/language/eof-parse-errors.bro
new file mode 100644
index 0000000000..a2c6edc66d
--- /dev/null
+++ b/testing/btest/language/eof-parse-errors.bro
@@ -0,0 +1,21 @@
+# @TEST-EXEC-FAIL: bro -b a.bro >output1 2>&1
+# @TEST-EXEC-FAIL: bro -b a.bro b.bro >output2 2>&1
+# @TEST-EXEC: btest-diff output1
+# @TEST-EXEC: btest-diff output2
+
+@TEST-START-FILE a.bro
+module A;
+
+event bro_init()
+	{
+	print "a";
+@TEST-END-FILE
+
+@TEST-START-FILE b.bro
+module B;
+
+event bro_init()
+	{
+	print "b";
+	}
+@TEST-END-FILE