1 files changed, 80 insertions, 0 deletions
diff --git a/src/section/function.c b/src/section/function.c
new file mode 100644
index 0000000..f03971c
--- /dev/null
+++ b/src/section/function.c
@@ -0,0 +1,80 @@
+#include <sections.h>
+#include <wasm_types.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+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 count failed\n", __func__);
+        return -1;
+    }
+
+    for (varuint32 i = 0; i < count; i++)
+    {
+        varuint32 type;
+
+        if (varuint32_read(f, &type))
+        {
+            fprintf(stderr, "%s: varuint32_read 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_function(struct wasmfs *const w, FILE *const f,
+    const unsigned long len)
+{
+    if (w->sections.function)
+    {
+        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.function = offset;
+    return 0;
+}