fix(kernel): finish Posix -1/errno for file ops and open EACCES (#567)

Map UnauthorizedAccess on open to PERMISSION_DENIED and route Posix lseek/pread/pwrite/rename/etc failures through PosixFailure so libc-style callers get RAX=-1 plus TLS errno, matching open/read/write.
2026-07-30 22:49:53 +08:00 · 2026-07-23 15:32:56 +03:00
parent d7bd814fb9
commit 956da769a3
3 changed files with 185 additions and 13 deletions
@@ -125,6 +125,125 @@ public sealed class KernelMemoryCompatExportsTests
        Assert.Equal(ulong.MaxValue, context[CpuRegister.Rax]);
    }

+    // FreeBSD/PS4 EBADF; PosixFailure maps ORBIS NOT_FOUND on fd calls to this.
+    private const int Ebadf = 9;
+    // FreeBSD/PS4 EACCES; PosixFailure maps ORBIS PERMISSION_DENIED to this.
+    private const int Eacces = 13;
+    // TLS slot used by KernelRuntimeCompatExports.TrySetErrno (FsBase + 0x40).
+    private const ulong TlsErrnoOffset = 0x40;
+
+    [Fact]
+    public void PosixLseek_BadDescriptorReturnsMinusOneWithEbadf()
+    {
+        const ulong memoryBase = 0x1_0000_0000;
+        const ulong fsBase = memoryBase + 0x100;
+        var memory = new FakeCpuMemory(memoryBase, 0x1000);
+        var context = new CpuContext(memory, Generation.Gen5)
+        {
+            FsBase = fsBase,
+        };
+        context[CpuRegister.Rdi] = 0x80020002; // never-opened / sentinel fd
+        context[CpuRegister.Rsi] = 0;
+        context[CpuRegister.Rdx] = 0; // SEEK_SET
+
+        var result = KernelMemoryCompatExports.PosixLseek(context);
+
+        Assert.Equal(-1, result);
+        Assert.Equal(ulong.MaxValue, context[CpuRegister.Rax]);
+        Assert.Equal(Ebadf, ReadErrno(memory, fsBase));
+    }
+
+    [Fact]
+    public void PosixPread_BadDescriptorReturnsMinusOneWithEbadf()
+    {
+        const ulong memoryBase = 0x1_0000_0000;
+        const ulong bufferAddress = memoryBase + 0x200;
+        const ulong fsBase = memoryBase + 0x100;
+        var memory = new FakeCpuMemory(memoryBase, 0x1000);
+        var context = new CpuContext(memory, Generation.Gen5)
+        {
+            FsBase = fsBase,
+        };
+        context[CpuRegister.Rdi] = 0x80020002; // never-opened / sentinel fd
+        context[CpuRegister.Rsi] = bufferAddress;
+        context[CpuRegister.Rdx] = 0x40;
+        context[CpuRegister.Rcx] = 0; // offset
+
+        var result = KernelMemoryCompatExports.PosixPread(context);
+
+        Assert.Equal(-1, result);
+        Assert.Equal(ulong.MaxValue, context[CpuRegister.Rax]);
+        Assert.Equal(Ebadf, ReadErrno(memory, fsBase));
+    }
+
+    [Fact]
+    public void KernelPread_BadDescriptorStillReturnsOrbisNotFound()
+    {
+        // sceKernel* entry points keep the raw Orbis ABI; only Posix* maps to -1/errno.
+        const ulong memoryBase = 0x1_0000_0000;
+        const ulong bufferAddress = memoryBase + 0x200;
+        var memory = new FakeCpuMemory(memoryBase, 0x1000);
+        var context = new CpuContext(memory, Generation.Gen5);
+        context[CpuRegister.Rdi] = 0x80020002;
+        context[CpuRegister.Rsi] = bufferAddress;
+        context[CpuRegister.Rdx] = 0x40;
+        context[CpuRegister.Rcx] = 0;
+
+        var result = KernelMemoryCompatExports.KernelPread(context);
+
+        Assert.Equal((int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND, result);
+    }
+
+    [Fact]
+    public void PosixOpen_MutatingApp0ReturnsMinusOneWithEacces()
+    {
+        // /app0 is read-only for mutating opens (retail semantics). That path
+        // returns PERMISSION_DENIED which PosixFailure maps to EACCES - the same
+        // errno UnauthorizedAccessException open failures now produce.
+        var tempRoot = Path.Combine(
+            Path.GetTempPath(),
+            $"sharpemu-posix-open-eacces-{Guid.NewGuid():N}");
+        var app0Root = Path.Combine(tempRoot, "app0");
+        Directory.CreateDirectory(app0Root);
+        KernelMemoryCompatExports.RegisterGuestPathMount("/app0", app0Root);
+
+        try
+        {
+            const ulong memoryBase = 0x1_0000_0000;
+            const ulong pathAddress = memoryBase + 0x200;
+            const ulong fsBase = memoryBase + 0x100;
+            var memory = new FakeCpuMemory(memoryBase, 0x1000);
+            var context = new CpuContext(memory, Generation.Gen5)
+            {
+                FsBase = fsBase,
+            };
+            memory.WriteCString(pathAddress, "/app0/readonly-create.bin");
+            context[CpuRegister.Rdi] = pathAddress;
+            context[CpuRegister.Rsi] = 0x0201; // O_WRONLY | O_CREAT
+
+            var result = KernelMemoryCompatExports.PosixOpen(context);
+
+            Assert.Equal(-1, result);
+            Assert.Equal(ulong.MaxValue, context[CpuRegister.Rax]);
+            Assert.Equal(Eacces, ReadErrno(memory, fsBase));
+        }
+        finally
+        {
+            KernelMemoryCompatExports.UnregisterGuestPathMount("/app0");
+            if (Directory.Exists(tempRoot))
+            {
+                Directory.Delete(tempRoot, recursive: true);
+            }
+        }
+    }
+
+    private static int ReadErrno(FakeCpuMemory memory, ulong fsBase)
+    {
+        Span<byte> bytes = stackalloc byte[sizeof(int)];
+        Assert.True(memory.TryRead(fsBase + TlsErrnoOffset, bytes));
+        return BitConverter.ToInt32(bytes);
+    }
+
    [Fact]
    public void Sprintf_ReadsVariadicDoubleFromXmmRegister()
    {