From f25b015e5b668028c34974bbb22faa4105c26690 Mon Sep 17 00:00:00 2001
From: Xavier Del Campo Romero <xavi.dcr@tutanota.com>
Date: Sun, 26 Nov 2023 22:43:30 +0100
Subject: First commit

---
 src/section/memory.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 src/section/memory.c

(limited to 'src/section/memory.c')

diff --git a/src/section/memory.c b/src/section/memory.c
new file mode 100644
index 0000000..0de5b4c
--- /dev/null
+++ b/src/section/memory.c
@@ -0,0 +1,102 @@
+/*
+ * nanowasm, a tiny WebAssembly/Wasm interpreter
+ * Copyright (C) 2023-2024  Xavier Del Campo Romero
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#include <nw/log.h>
+#include <nw/sections.h>
+#include <nanowasm/nw.h>
+#include <nw/types.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+static int check_memory_type(FILE *const f, struct resizable_limits *const r)
+{
+    return check_resizable_limits(f, r);
+}
+
+static int check(FILE *const f, const unsigned long len,
+    struct resizable_limits *const r)
+{
+    const long start = ftell(f);
+
+    if (start < 0)
+    {
+        LOG("%s: ftell(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+
+    varuint32 count;
+
+    if (varuint32_read(f, &count))
+    {
+        LOG("%s: varuint32_read failed\n", __func__);
+        return 1;
+    }
+    else if (count > 1)
+    {
+        LOG("%s: only 1 memory allowed\n", __func__);
+        return 1;
+    }
+
+    for (varuint32 i = 0; i < count; i++)
+        if (check_memory_type(f, r))
+        {
+            LOG("%s: check_memory_type failed\n", __func__);
+            return -1;
+        }
+
+    const long end = ftell(f);
+
+    if (end < 0)
+    {
+        LOG("%s: ftell(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+
+    const unsigned long size = end - start;
+
+    if (size != len)
+    {
+        LOG("%s: size exceeded (%lu expected, got %lu)\n",
+                __func__, len, size);
+        return -1;
+    }
+
+    return 0;
+}
+
+int section_memory_check(const struct section *const s, struct nw_mod *const m,
+    const unsigned long len)
+{
+    FILE *const f = s->f;
+
+    if (m->sections.memory)
+    {
+        LOG("%s: ignoring duplicate section\n", __func__);
+        return fseek(f, len, SEEK_CUR);
+    }
+
+    const long offset = ftell(f);
+    struct resizable_limits r;
+
+    if (offset < 0)
+    {
+        LOG("%s: ftell(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+    else if (check(f, len, &r))
+    {
+        LOG("%s: check failed\n", __func__);
+        return -1;
+    }
+
+    m->heap_len = r.sz;
+    m->sections.memory = offset;
+    return 0;
+}
-- 
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