feat: implement mremap

runtime/experiments/applications/imageresize/by_resolution/run.sh

@@ -28,35 +28,30 @@ for ((i = 0; i < total_count; i++)); do
   ext="$RANDOM"
 
   curl -H 'Expect:' -H "Content-Type: image/jpg" --data-binary "@shrinking_man_small.jpg" --output "result_${ext}_small.png" localhost:10000 2>/dev/null 1>/dev/null
-  pixel_differences="$(compare -identify -metric AE "result_${ext}_small.png" expected_result.png null: 2>&1 >/dev/null)"
-  if [[ "$pixel_differences" == "0" ]]; then
-    success_count=$((success_count + 1))
-  else
+  pixel_differences="$(compare -identify -metric AE "result_${ext}_small.png" expected_result_small.png null: 2>&1 >/dev/null)"
+  if [[ "$pixel_differences" != "0" ]]; then
     echo "Small FAIL"
     echo "$pixel_differences pixel differences detected"
     exit
   fi
 
   curl -H 'Expect:' -H "Content-Type: image/jpg" --data-binary "@shrinking_man_medium.jpg" --output "result_${ext}_medium.png" localhost:10001 2>/dev/null 1>/dev/null
-  pixel_differences="$(compare -identify -metric AE "result_${ext}_medium.png" expected_result.png null: 2>&1 >/dev/null)"
-  if [[ "$pixel_differences" == "0" ]]; then
-    success_count=$((success_count + 1))
-  else
-    echo "Medium FAIL"
+  pixel_differences="$(compare -identify -metric AE "result_${ext}_medium.png" expected_result_medium.png null: 2>&1 >/dev/null)"
+  if [[ "$pixel_differences" != "0" ]]; then
+    echo "Small FAIL"
     echo "$pixel_differences pixel differences detected"
     exit
   fi
 
   curl -H 'Expect:' -H "Content-Type: image/jpg" --data-binary "@shrinking_man_large.jpg" --output "result_${ext}_large.png" localhost:10002 2>/dev/null 1>/dev/null
-  pixel_differences="$(compare -identify -metric AE "result_${ext}_large.png" expected_result.png null: 2>&1 >/dev/null)"
-
-  if [[ "$pixel_differences" == "0" ]]; then
-    success_count=$((success_count + 1))
-  else
-    echo "Large FAIL"
+  pixel_differences="$(compare -identify -metric AE "result_${ext}_large.png" expected_result_large.png null: 2>&1 >/dev/null)"
+  if [[ "$pixel_differences" != "0" ]]; then
+    echo "Small FAIL"
     echo "$pixel_differences pixel differences detected"
     exit
   fi
+
+  success_count=$((success_count + 1))
 done
 
 echo "$success_count / $total_count"

runtime/experiments/applications/imageresize/by_resolution/spec.json

@@ -35,8 +35,8 @@
   "argsize": 1,
   "http-req-headers": [],
   "http-req-content-type": "image/jpeg",
-  "http-req-size": 1024000,
+  "http-req-size": 1524000,
   "http-resp-headers": [],
-  "http-resp-size": 1024000,
+  "http-resp-size": 1524000,
   "http-resp-content-type": "image/png"
 }

runtime/src/libc/syscall.c

@@ -515,19 +515,44 @@ int32_t
 wasm_mremap(int32_t offset, int32_t old_size, int32_t new_size, int32_t flags)
 {
 	/* Should fit within the 32-bit linear address space */
-	/* TODO: Improve with errno */
-	assert(offset + old_size < INT32_MAX);
-	assert(new_size < INT32_MAX);
+	/* TODO: Improve with errno and handle flags properly */
+	// debuglog("Offset: %d, Old Size: %d, New Size: %d, May Move: %s, Fixed: %s\n", offset, old_size, new_size,
+	//          (flags & MREMAP_MAYMOVE) == MREMAP_MAYMOVE ? "true" : "false",
+	//          (flags & MREMAP_FIXED) == MREMAP_FIXED ? "true" : "false");
 
-	/* Not really implemented, so dump out usage to understand requirements */
-	debuglog("Offset: %d, Old Size: %d, New Size: %d, May Move: %s, Fixed: %s\n", offset, old_size, new_size,
-	         (flags & MREMAP_MAYMOVE) == MREMAP_MAYMOVE ? "true" : "false",
-	         (flags & MREMAP_FIXED) == MREMAP_FIXED ? "true" : "false");
+	assert(offset >= 0);
+	assert(offset + old_size <= INT32_MAX);
+
+	// We do not implement compaction yet, so just return immediately if shrinking
+	if (new_size <= old_size) return offset;
+
+	// If at end of linear memory, just expand and return same address
+	if (offset + old_size == local_sandbox_context_cache.linear_memory_size) {
+		int32_t amount_to_expand  = new_size - old_size;
+		int32_t pages_to_allocate = amount_to_expand / WASM_PAGE_SIZE;
+		if (amount_to_expand % WASM_PAGE_SIZE > 0) pages_to_allocate++;
+		for (int i = 0; i < pages_to_allocate; i++) expand_memory();
 
-	/* Return the current offset, hoping for the best */
 		return offset;
 	}
 
+	// Otherwise allocate at end of address space and copy
+	int32_t pages_to_allocate = new_size / WASM_PAGE_SIZE;
+	if (new_size % WASM_PAGE_SIZE > 0) pages_to_allocate++;
+	int32_t new_offset = local_sandbox_context_cache.linear_memory_size;
+	for (int i = 0; i < pages_to_allocate; i++) expand_memory();
+
+	// Get pointer of old offset and pointer of new offset
+	char *linear_mem = local_sandbox_context_cache.linear_memory_start;
+	char *src        = &linear_mem[offset];
+	char *dest       = &linear_mem[new_offset];
+
+	// Copy Values. We can use memcpy because we don't overlap
+	memcpy((void *)dest, (void *)src, old_size);
+
+	return new_offset;
+}
+
 #define SYS_MADVISE 28
 
 #define SYS_GETPID 39