fuse integration: add POSIX compliance test suite

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

test/fuse_integration/fallocate_darwin.go

@@ -0,0 +1,79 @@
+//go:build darwin
+
+package fuse
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// File allocation support for macOS using fcntl
+
+const (
+	// macOS doesn't have fallocate, but we can use fcntl with F_PREALLOCATE
+	F_ALLOCATECONTIG = 0x02
+	F_ALLOCATEALL    = 0x04
+
+	// Dummy flags for compatibility
+	FALLOC_FL_KEEP_SIZE      = 0x01
+	FALLOC_FL_PUNCH_HOLE     = 0x02
+	FALLOC_FL_NO_HIDE_STALE  = 0x04
+	FALLOC_FL_COLLAPSE_RANGE = 0x08
+	FALLOC_FL_ZERO_RANGE     = 0x10
+	FALLOC_FL_INSERT_RANGE   = 0x20
+	FALLOC_FL_UNSHARE_RANGE  = 0x40
+)
+
+// fstore_t structure for F_PREALLOCATE
+type fstore struct {
+	flags      uint32
+	posmode    int16
+	offset     int64
+	length     int64
+	bytesalloc int64
+}
+
+func fallocateFile(fd int, mode int, offset int64, length int64) error {
+	// Check for unsupported modes on macOS
+	unsupportedModes := FALLOC_FL_PUNCH_HOLE | FALLOC_FL_NO_HIDE_STALE | FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | FALLOC_FL_INSERT_RANGE | FALLOC_FL_UNSHARE_RANGE
+	if mode&unsupportedModes != 0 {
+		return syscall.ENOTSUP // Operation not supported
+	}
+
+	// On macOS, we use fcntl with F_PREALLOCATE
+	store := fstore{
+		flags:   F_ALLOCATECONTIG,
+		posmode: syscall.F_PEOFPOSMODE, // Allocate from EOF
+		offset:  0,
+		length:  length,
+	}
+
+	_, _, errno := syscall.Syscall(syscall.SYS_FCNTL,
+		uintptr(fd),
+		syscall.F_PREALLOCATE,
+		uintptr(unsafe.Pointer(&store)))
+
+	if errno != 0 {
+		// If contiguous allocation fails, try non-contiguous
+		store.flags = F_ALLOCATEALL
+		_, _, errno = syscall.Syscall(syscall.SYS_FCNTL,
+			uintptr(fd),
+			syscall.F_PREALLOCATE,
+			uintptr(unsafe.Pointer(&store)))
+
+		if errno != 0 {
+			return errno
+		}
+	}
+
+	// Set file size if not keeping size
+	if mode&FALLOC_FL_KEEP_SIZE == 0 {
+		return syscall.Ftruncate(fd, offset+length)
+	}
+
+	return nil
+}
+
+func isFallocateSupported() bool {
+	return true
+}