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.

src/SharpEmu.Libs/Kernel/KernelFileExtendedExports.cs

@@ -46,7 +46,13 @@ public static partial class KernelMemoryCompatExports
 
     [SysAbiExport(Nid = "ezv-RSBNKqI", ExportName = "pread",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
-    public static int PosixPread(CpuContext ctx) => KernelPreadCore(ctx);
+    public static int PosixPread(CpuContext ctx)
+    {
+        var result = KernelPreadCore(ctx);
+        return result == (int)OrbisGen2Result.ORBIS_GEN2_OK
+            ? 0
+            : PosixFailure(ctx, result, notFoundErrno: Ebadf);
+    }
 
     [SysAbiExport(Nid = "+r3rMFwItV4", ExportName = "sceKernelPread",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
@@ -97,7 +103,13 @@ public static partial class KernelMemoryCompatExports
 
     [SysAbiExport(Nid = "C2kJ-byS5rM", ExportName = "pwrite",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
-    public static int PosixPwrite(CpuContext ctx) => KernelPwriteCore(ctx);
+    public static int PosixPwrite(CpuContext ctx)
+    {
+        var result = KernelPwriteCore(ctx);
+        return result == (int)OrbisGen2Result.ORBIS_GEN2_OK
+            ? 0
+            : PosixFailure(ctx, result, notFoundErrno: Ebadf);
+    }
 
     [SysAbiExport(Nid = "nKWi-N2HBV4", ExportName = "sceKernelPwrite",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
@@ -149,7 +161,13 @@ public static partial class KernelMemoryCompatExports
 
     [SysAbiExport(Nid = "juWbTNM+8hw", ExportName = "fsync",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
-    public static int PosixFsync(CpuContext ctx) => KernelFsyncCore(ctx);
+    public static int PosixFsync(CpuContext ctx)
+    {
+        var result = KernelFsyncCore(ctx);
+        return result == (int)OrbisGen2Result.ORBIS_GEN2_OK
+            ? 0
+            : PosixFailure(ctx, result, notFoundErrno: Ebadf);
+    }
 
     [SysAbiExport(Nid = "fTx66l5iWIA", ExportName = "sceKernelFsync",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
@@ -157,7 +175,13 @@ public static partial class KernelMemoryCompatExports
 
     [SysAbiExport(Nid = "KIbJFQ0I1Cg", ExportName = "fdatasync",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
-    public static int PosixFdatasync(CpuContext ctx) => KernelFsyncCore(ctx);
+    public static int PosixFdatasync(CpuContext ctx)
+    {
+        var result = KernelFsyncCore(ctx);
+        return result == (int)OrbisGen2Result.ORBIS_GEN2_OK
+            ? 0
+            : PosixFailure(ctx, result, notFoundErrno: Ebadf);
+    }
 
     [SysAbiExport(Nid = "30Rh4ixbKy4", ExportName = "sceKernelFdatasync",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
@@ -210,7 +234,13 @@ public static partial class KernelMemoryCompatExports
 
     [SysAbiExport(Nid = "ih4CD9-gghM", ExportName = "ftruncate",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
-    public static int PosixFtruncate(CpuContext ctx) => KernelFtruncateCore(ctx);
+    public static int PosixFtruncate(CpuContext ctx)
+    {
+        var result = KernelFtruncateCore(ctx);
+        return result == (int)OrbisGen2Result.ORBIS_GEN2_OK
+            ? 0
+            : PosixFailure(ctx, result, notFoundErrno: Ebadf);
+    }
 
     [SysAbiExport(Nid = "VW3TVZiM4-E", ExportName = "sceKernelFtruncate",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
@@ -246,7 +276,13 @@ public static partial class KernelMemoryCompatExports
 
     [SysAbiExport(Nid = "ayrtszI7GBg", ExportName = "truncate",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
-    public static int PosixTruncate(CpuContext ctx) => KernelTruncateCore(ctx);
+    public static int PosixTruncate(CpuContext ctx)
+    {
+        var result = KernelTruncateCore(ctx);
+        return result == (int)OrbisGen2Result.ORBIS_GEN2_OK
+            ? 0
+            : PosixFailure(ctx, result);
+    }
 
     [SysAbiExport(Nid = "WlyEA-sLDf0", ExportName = "sceKernelTruncate",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
@@ -294,7 +330,13 @@ public static partial class KernelMemoryCompatExports
 
     [SysAbiExport(Nid = "NN01qLRhiqU", ExportName = "rename",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
-    public static int PosixRename(CpuContext ctx) => KernelRenameCore(ctx);
+    public static int PosixRename(CpuContext ctx)
+    {
+        var result = KernelRenameCore(ctx);
+        return result == (int)OrbisGen2Result.ORBIS_GEN2_OK
+            ? 0
+            : PosixFailure(ctx, result);
+    }
 
     [SysAbiExport(Nid = "52NcYU9+lEo", ExportName = "sceKernelRename",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
@@ -363,7 +405,10 @@ public static partial class KernelMemoryCompatExports
         {
             if (!_openFiles.TryGetValue(fd, out var stream))
             {
-                return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND;
+                return PosixFailure(
+                    ctx,
+                    (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND,
+                    notFoundErrno: Ebadf);
             }
 
             // POSIX dup shares the open file description (and offset), which is
@@ -386,7 +431,10 @@ public static partial class KernelMemoryCompatExports
         {
             if (!_openFiles.TryGetValue(oldFd, out var stream))
             {
-                return (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND;
+                return PosixFailure(
+                    ctx,
+                    (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND,
+                    notFoundErrno: Ebadf);
             }
 
             if (oldFd == newFd)
@@ -412,7 +460,13 @@ public static partial class KernelMemoryCompatExports
 
     [SysAbiExport(Nid = "8nY19bKoiZk", ExportName = "fcntl",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]
-    public static int PosixFcntl(CpuContext ctx) => KernelFcntlCore(ctx);
+    public static int PosixFcntl(CpuContext ctx)
+    {
+        var result = KernelFcntlCore(ctx);
+        return result == (int)OrbisGen2Result.ORBIS_GEN2_OK
+            ? 0
+            : PosixFailure(ctx, result, notFoundErrno: Ebadf);
+    }
 
     [SysAbiExport(Nid = "SoZkxZkCHaw", ExportName = "sceKernelFcntl",
         Target = Generation.Gen4 | Generation.Gen5, LibraryName = "libKernel")]

src/SharpEmu.Libs/Kernel/KernelMemoryCompatExports.cs

@@ -1558,7 +1558,7 @@ public static partial class KernelMemoryCompatExports
         {
             LogOpenTrace($"_open fail path='{guestPath}' host='{hostPath}' flags=0x{flags:X8} ex={ex.GetType().Name}: {ex.Message}");
             return ex is UnauthorizedAccessException
-                ? (int)OrbisGen2Result.ORBIS_GEN2_ERROR_INVALID_ARGUMENT
+                ? (int)OrbisGen2Result.ORBIS_GEN2_ERROR_PERMISSION_DENIED
                 : (int)OrbisGen2Result.ORBIS_GEN2_ERROR_NOT_FOUND;
         }
     }
@@ -2228,8 +2228,7 @@ public static partial class KernelMemoryCompatExports
 
         if (result != OrbisGen2Result.ORBIS_GEN2_OK)
         {
-            ctx[CpuRegister.Rax] = ulong.MaxValue;
-            return (int)OrbisGen2Result.ORBIS_GEN2_OK;
+            return PosixFailure(ctx, (int)result, notFoundErrno: Ebadf);
         }
 
         ctx[CpuRegister.Rax] = unchecked((ulong)position);

tests/SharpEmu.Libs.Tests/Kernel/KernelMemoryCompatExportsTests.cs

@@ -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()
     {