First commitfirst-step

1 files changed, 96 insertions, 0 deletions

diff --git a/src/section/table.c b/src/section/table.c
new file mode 100644
index 0000000..9f793c7
--- /dev/null
+++ b/src/section/table.c
@@ -0,0 +1,96 @@
+#include <sections.h>
+#include <wasm_types.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+static int check_table_type(FILE *const f)
+{
+    enum {ANYFUNC = 0x70};
+    varint7 elem_type;
+
+    if (varint7_read(f, &elem_type))
+    {
+        fprintf(stderr, "%s: varint7_read failed\n", __func__);
+        return -1;
+    }
+    else if (elem_type != ANYFUNC)
+    {
+        fprintf(stderr, "%s: expected %x, got %x", __func__, ANYFUNC,
+            (int)elem_type);
+        return -1;
+    }
+
+    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_table_type(f))
+        {
+            fprintf(stderr, "%s: check_table_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_table(struct wasmfs *const w, FILE *const f,
+    const unsigned long len)
+{
+    if (w->sections.table)
+    {
+        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.table = offset;
+    return 0;
+}