From 52c18e60929b64285d4bb333f87482d954c9b2e0 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 | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 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..aba461a
--- /dev/null
+++ b/src/section/memory.c
@@ -0,0 +1,81 @@
+#include <sections.h>
+#include <wasm_types.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+static int check_memory_type(FILE *const f)
+{
+    return check_resizable_limits(f);
+}
+
+static int check(FILE *const f, const unsigned long len)
+{
+    const long start = ftell(f);
+
+    if (start < 0)
+    {
+        fprintf(stderr, "%s: ftell(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+
+    varuint32 count;
+
+    if (varuint32_read(f, &count))
+    {
+        fprintf(stderr, "%s: varuint32_read failed\n", __func__);
+        return -1;
+    }
+
+    for (varuint32 i = 0; i < count; i++)
+        if (check_memory_type(f))
+        {
+            fprintf(stderr, "%s: check_memory_type failed\n", __func__);
+            return -1;
+        }
+
+    const long end = ftell(f);
+
+    if (end < 0)
+    {
+        fprintf(stderr, "%s: ftell(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+
+    const unsigned long size = end - start;
+
+    if (size != len)
+    {
+        fprintf(stderr, "%s: size exceeded (%lu expected, got %lu)\n",
+                __func__, len, size);
+        return -1;
+    }
+
+    return 0;
+}
+
+int section_memory(struct wasmfs *const w, FILE *const f,
+    const unsigned long len)
+{
+    if (w->sections.memory)
+    {
+        fprintf(stderr, "%s: ignoring duplicate section\n", __func__);
+        return 0;
+    }
+
+    const long offset = ftell(f);
+
+    if (offset < 0)
+    {
+        fprintf(stderr, "%s: ftell(3): %s\n", __func__, strerror(errno));
+        return -1;
+    }
+    else if (check(f, len))
+    {
+        fprintf(stderr, "%s: check failed\n", __func__);
+        return -1;
+    }
+
+    w->sections.memory = offset;
+    return 0;
+}
-- 
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