UserspaceEmulator: Support the name argument in mmap for file backed mappings

DevTools/UserspaceEmulator/Emulator.cpp

@@ -874,11 +874,27 @@ u32 Emulator::virt$mmap(u32 params_addr)
 
     u32 final_size = round_up_to_power_of_two(params.size, PAGE_SIZE);
     u32 final_address = allocate_vm(final_size, params.alignment);
+    if (params.addr != 0) {
+        // NOTE: We currently do not support allocating VM at a requeted address in the emulator.
+        // The loader needs this functionality to load .data just after .text.
+        // Luckily, since the loader calls mmap for .data right after it calls mmap for .text,
+        // the emulator will allocate a chunk of memory that is just after what we allocated for .text
+        // becuase of the way we currently allocate VM.
+        ASSERT(params.addr == final_address);
+    }
 
     if (params.flags & MAP_ANONYMOUS)
         mmu().add_region(MmapRegion::create_anonymous(final_address, final_size, params.prot));
-    else
-        mmu().add_region(MmapRegion::create_file_backed(final_address, final_size, params.prot, params.flags, params.fd, params.offset));
+    else {
+        dbgln("chars: {:p}, len: {}", params.name.characters, params.name.length);
+        String name_str;
+        if (params.name.characters) {
+            auto name = ByteBuffer::create_uninitialized(params.name.length);
+            mmu().copy_from_vm(name.data(), (FlatPtr)params.name.characters, params.name.length);
+            name_str = { name.data(), name.size() };
+        }
+        mmu().add_region(MmapRegion::create_file_backed(final_address, final_size, params.prot, params.flags, params.fd, params.offset, name_str));
+    }
 
     return final_address;
 }

DevTools/UserspaceEmulator/MmapRegion.cpp

@@ -39,11 +39,16 @@ NonnullOwnPtr<MmapRegion> MmapRegion::create_anonymous(u32 base, u32 size, u32 p
     return region;
 }
 
-NonnullOwnPtr<MmapRegion> MmapRegion::create_file_backed(u32 base, u32 size, u32 prot, int flags, int fd, off_t offset)
+NonnullOwnPtr<MmapRegion> MmapRegion::create_file_backed(u32 base, u32 size, u32 prot, int flags, int fd, off_t offset, String name)
 {
     auto region = adopt_own(*new MmapRegion(base, size, prot));
     region->m_file_backed = true;
-    region->m_data = (u8*)mmap(nullptr, size, prot, flags, fd, offset);
+    if (!name.is_empty()) {
+        dbgln("name is not empty");
+        name = String::format("%s (Emulated)", name.characters());
+        region->m_name = name;
+    }
+    region->m_data = (u8*)mmap_with_name(nullptr, size, prot, flags, fd, offset, name.is_empty() ? nullptr : name.characters());
     ASSERT(region->m_data != MAP_FAILED);
     return region;
 }

DevTools/UserspaceEmulator/MmapRegion.h

@@ -37,7 +37,7 @@ class MallocTracer;
 class MmapRegion final : public Region {
 public:
     static NonnullOwnPtr<MmapRegion> create_anonymous(u32 base, u32 size, u32 prot);
-    static NonnullOwnPtr<MmapRegion> create_file_backed(u32 base, u32 size, u32 prot, int flags, int fd, off_t offset);
+    static NonnullOwnPtr<MmapRegion> create_file_backed(u32 base, u32 size, u32 prot, int flags, int fd, off_t offset, String name = {});
     virtual ~MmapRegion() override;
 
     virtual ValueWithShadow<u8> read8(u32 offset) override;
@@ -71,6 +71,7 @@ private:
     bool m_malloc { false };
 
     OwnPtr<MallocRegionMetadata> m_malloc_metadata;
+    String m_name;
 };
 
 }