resources: Fix zero-length buffer being passed to readHooked

1 files changed, 35 insertions, 6 deletions

diff --git a/src/lib/resources.zig b/src/lib/resources.zig
index 0c87ede..004b82a 100644
--- a/src/lib/resources.zig
+++ b/src/lib/resources.zig
@@ -101,8 +101,6 @@ const processfs = struct {
         var buffer = std.ArrayListAligned(u8, paging.page_size).init(allocator);
         defer buffer.clearAndFree();
 
-        try buffer.ensureUnusedCapacity(4096);
-
         const ctx = try allocator.create(CreationContext);
         defer allocator.destroy(ctx);
 
@@ -115,10 +113,26 @@ const processfs = struct {
         paging.setUserMemoryAccess(false);
 
         defer proc.allowResume();
-        while (try rd.readHooked(proc, ctx.buffer.items, .{
+
+        try ctx.buffer.ensureUnusedCapacity(4096);
+
+        var unused_capacity = ctx.buffer.allocatedSlice()[ctx.buffer.items.len..];
+        var n = try rd.readHooked(proc, unused_capacity, .{
             .hookFn = loadExe,
             .context = ctx,
-        }) > 0) {}
+        });
+        while (n > 0) {
+            try buffer.ensureUnusedCapacity(4096);
+
+            unused_capacity = ctx.buffer.allocatedSlice()[ctx.buffer.items.len..];
+            n = try rd.readHooked(proc, unused_capacity, .{
+                .hookFn = loadExe,
+                .context = ctx,
+            });
+
+            ctx.buffer.items.len += n;
+        }
+
         const new_proc = try process.create(allocator, ctx.buffer.items);
         return new_proc.id;
     }
@@ -159,12 +173,27 @@ const processfs = struct {
             return;
         }
 
+        ctx.buffer.items.len += n;
+
         try ctx.buffer.ensureUnusedCapacity(4096);
 
-        while (try ctx.rd.readHooked(ctx.proc, ctx.buffer.items[ctx.buffer.items.len..], .{
+        var unused_capacity = ctx.buffer.allocatedSlice()[ctx.buffer.items.len..];
+        var n2 = try ctx.rd.readHooked(ctx.proc, unused_capacity, .{
             .hookFn = loadExe,
             .context = ctx,
-        }) > 0) {}
+        });
+        while (n2 > 0) {
+            try ctx.buffer.ensureUnusedCapacity(4096);
+
+            unused_capacity = ctx.buffer.allocatedSlice()[ctx.buffer.items.len..];
+            n2 = try ctx.rd.readHooked(ctx.proc, unused_capacity, .{
+                .hookFn = loadExe,
+                .context = ctx,
+            });
+
+            ctx.buffer.items.len += n2;
+        }
+
         const new_proc = try process.create(allocator, ctx.buffer.items);
         sysexchange.frameReturn(null, &ctx.proc.trap_frame, new_proc.id);
     }