From a7f00a4e84f1db436017172dd96b8ea42abc2723 Mon Sep 17 00:00:00 2001
From: krangelov <kr.angelov@gmail.com>
Date: Sun, 12 Sep 2021 08:11:10 +0200
Subject: [PATCH] detect and report an attempt to load non .ngf file in readNGF

---
 src/runtime/c/pgf/db.cxx           | 13 +++++++++++++
 src/runtime/haskell/tests/basic.hs | 14 ++++++--------
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/runtime/c/pgf/db.cxx b/src/runtime/c/pgf/db.cxx
index 9c7f3ca7a..d96888e00 100644
--- a/src/runtime/c/pgf/db.cxx
+++ b/src/runtime/c/pgf/db.cxx
@@ -250,8 +250,16 @@ typedef struct mchunk mbin;
  */
 #define FASTBIN_CONSOLIDATION_THRESHOLD  (65536UL)
 
+static char slovo[5] = {'S','L','O','V','O'};
+
 struct PGF_INTERNAL_DECL malloc_state
 {
+    /* Each .ngf file starts with 'SLOVO' as in:
+     *    "V načaloto be slovoto" (In the beginning was the word)
+     * In this way we detect an attempt to read a non .ngf file.
+     */
+    char sign[5];
+
     /* Set if the fastbin chunks contain recently inserted free blocks.  */
     bool have_fastchunks;
     /* Fastbins */
@@ -320,6 +328,9 @@ PgfDB::PgfDB(const char* filepath, int flags, int mode) {
     if (is_new) {
         init_state(file_size);
     } else {
+        if (strncmp(ms->sign, slovo, sizeof(ms->sign)) != 0)
+            throw pgf_error("Invalid file content");
+
         // We must make sure that left-over transient revisions are
         // released. This may happen if a client process was killed
         // or if the garbadge collector has not managed to run
@@ -366,6 +377,8 @@ void PgfDB::set_revision(ref<PgfPGF> pgf)
 PGF_INTERNAL
 void PgfDB::init_state(size_t size)
 {
+    memcpy(ms->sign, slovo, sizeof(ms->sign));
+
     /* Init fastbins */
     ms->have_fastchunks = false;
     for (int i = 0; i < NFASTBINS; ++i) {
diff --git a/src/runtime/haskell/tests/basic.hs b/src/runtime/haskell/tests/basic.hs
index 0a5783e67..a2a28aaba 100644
--- a/src/runtime/haskell/tests/basic.hs
+++ b/src/runtime/haskell/tests/basic.hs
@@ -79,29 +79,27 @@ main = do
 
   rp1 <- testLoadFailure (readPGF "non-existing.pgf")
   rp2 <- testLoadFailure (readPGF "tests/basic.gf")
-  -- rp3 <- testLoadFailure (readPGF "tests/basic.ngf")
+  rp3 <- testLoadFailure (readPGF "tests/basic.ngf")
 
   bn1 <- testLoadFailure (bootNGF "non-existing.pgf" "non-existing.ngf")
   bn2 <- testLoadFailure (bootNGF "tests/basic.gf" "tests/basic.ngf")
   bn3 <- testLoadFailure (bootNGF "tests/basic.ngf" "tests/basic.pgf")
 
-  -- rn1 <- testLoadFailure (readNGF "non-existing.ngf")
-  -- rn2 <- testLoadFailure (readNGF "tests/basic.gf")
-  -- rn3 <- testLoadFailure (readNGF "tests/basic.pgf")
+  rn2 <- testLoadFailure (readNGF "tests/basic.gf")
+  rn3 <- testLoadFailure (readNGF "tests/basic.pgf")
 
   runTestTTAndExit $
     TestList $
       [TestCase (assertBool "missing file" rp1)
       ,TestCase (assertBool "wrong file format (GF)" rp2)
-      -- ,TestCase (assertBool "wrong file format (NGF)" rp3)
+      ,TestCase (assertBool "wrong file format (NGF)" rp3)
 
       ,TestCase (assertBool "missing file" bn1)
       ,TestCase (assertBool "wrong file format (GF)" bn2)
       ,TestCase (assertBool "wrong file format (NGF)" bn3)
 
-      -- ,TestCase (assertBool "missing file" rn1)
-      -- ,TestCase (assertBool "wrong file format (GF)" rn2)
-      -- ,TestCase (assertBool "wrong file format (PGF)" rn3)
+      ,TestCase (assertBool "wrong file format (GF)" rn2)
+      ,TestCase (assertBool "wrong file format (PGF)" rn3)
       ]
       ++ grammarTests gr1
       ++ grammarTests gr2