more on integration tests

1 files changed, 1098 insertions, 24 deletions

diff --git a/integrationtests/cmd/ioworkload/scenarios.go b/integrationtests/cmd/ioworkload/scenarios.go
index 41563d8..bf1561c 100644
--- a/integrationtests/cmd/ioworkload/scenarios.go
+++ b/integrationtests/cmd/ioworkload/scenarios.go
@@ -4,22 +4,50 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"runtime"
 	"syscall"
+	"unsafe"
 )
 
 // scenarios maps scenario names to their execution functions.
 var scenarios = map[string]func() error{
-	"open-basic":      openBasic,
-	"open-creat":      openCreat,
-	"readwrite-basic": readwriteBasic,
+	"open-basic":          openBasic,
+	"open-creat":          openCreat,
+	"open-by-handle-at":   openByHandleAt,
+	"readwrite-basic":   readwriteBasic,
+	"readwrite-pread":   readwritePread,
+	"readwrite-pwrite":  readwritePwrite,
+	"readwrite-readv":   readwriteReadv,
+	"readwrite-writev":  readwriteWritev,
 	"close-basic":     closeBasic,
+	"close-range":     closeRange,
 	"dup-basic":       dupBasic,
-	"fcntl-dupfd":     fcntlDupfd,
-	"rename-basic":    renameBasic,
+	"dup-dup2":        dupDup2,
+	"dup-dup3":        dupDup3,
+	"fcntl-dupfd":          fcntlDupfd,
+	"fcntl-setfl":          fcntlSetfl,
+	"fcntl-dupfd-cloexec":  fcntlDupfdCloexec,
+	"rename-basic":         renameBasic,
+	"rename-renameat":      renameRenameat,
+	"rename-renameat2":     renameRenameat2,
 	"link-basic":      linkBasic,
+	"link-linkat":     linkLinkat,
+	"link-symlinkat":  linkSymlinkat,
+	"link-readlinkat": linkReadlinkat,
 	"unlink-basic":    unlinkBasic,
+	"unlink-unlinkat": unlinkUnlinkat,
+	"unlink-rmdir":    unlinkRmdir,
 	"dir-basic":       dirBasic,
+	"dir-mkdirat":     dirMkdirat,
+	"dir-chdir":       dirChdir,
+	"dir-getdents":    dirGetdents,
 	"stat-basic":      statBasic,
+	"stat-fstat":      statFstat,
+	"stat-lstat":      statLstat,
+	"stat-newfstatat": statNewfstatat,
+	"stat-statx":      statStatx,
+	"stat-access":     statAccess,
+	"stat-faccessat":  statFaccessat,
 	"sync-basic":      syncBasic,
 	"truncate-basic":  truncateBasic,
 }
@@ -95,6 +123,122 @@ func readwriteBasic() error {
 	return nil
 }
 
+// readwritePread opens a file, writes data, then reads it back via pread64.
+func readwritePread() error {
+	dir, cleanup, err := makeTempDir("readwrite-pread")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "preadfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	data := []byte("pread test data")
+	if _, err := syscall.Write(fd, data); err != nil {
+		return fmt.Errorf("write: %w", err)
+	}
+
+	buf := make([]byte, len(data))
+	if _, err := syscall.Pread(fd, buf, 0); err != nil {
+		return fmt.Errorf("pread: %w", err)
+	}
+	return nil
+}
+
+// readwritePwrite opens a file and writes data via pwrite64.
+func readwritePwrite() error {
+	dir, cleanup, err := makeTempDir("readwrite-pwrite")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "pwritefile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	if _, err := syscall.Pwrite(fd, []byte("pwrite test data"), 0); err != nil {
+		return fmt.Errorf("pwrite: %w", err)
+	}
+	return nil
+}
+
+// readwriteReadv opens a file, writes data, then reads it back via readv.
+func readwriteReadv() error {
+	dir, cleanup, err := makeTempDir("readwrite-readv")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "readvfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	data := []byte("readv test data here")
+	if _, err := syscall.Write(fd, data); err != nil {
+		return fmt.Errorf("write: %w", err)
+	}
+	if _, err := syscall.Seek(fd, 0, 0); err != nil {
+		return fmt.Errorf("seek: %w", err)
+	}
+
+	buf1 := make([]byte, 5)
+	buf2 := make([]byte, 15)
+	iovs := []syscall.Iovec{
+		{Base: &buf1[0], Len: uint64(len(buf1))},
+		{Base: &buf2[0], Len: uint64(len(buf2))},
+	}
+	_, _, errno := syscall.Syscall(syscall.SYS_READV, uintptr(fd), uintptr(unsafe.Pointer(&iovs[0])), uintptr(len(iovs)))
+	runtime.KeepAlive(buf1)
+	runtime.KeepAlive(buf2)
+	if errno != 0 {
+		return fmt.Errorf("readv: %w", errno)
+	}
+	return nil
+}
+
+// readwriteWritev opens a file and writes data via writev.
+func readwriteWritev() error {
+	dir, cleanup, err := makeTempDir("readwrite-writev")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "writevfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	buf1 := []byte("writev ")
+	buf2 := []byte("test data")
+	iovs := []syscall.Iovec{
+		{Base: &buf1[0], Len: uint64(len(buf1))},
+		{Base: &buf2[0], Len: uint64(len(buf2))},
+	}
+	_, _, errno := syscall.Syscall(syscall.SYS_WRITEV, uintptr(fd), uintptr(unsafe.Pointer(&iovs[0])), uintptr(len(iovs)))
+	runtime.KeepAlive(buf1)
+	runtime.KeepAlive(buf2)
+	if errno != 0 {
+		return fmt.Errorf("writev: %w", errno)
+	}
+	return nil
+}
+
 // closeBasic opens multiple files and closes them.
 func closeBasic() error {
 	dir, cleanup, err := makeTempDir("close-basic")
@@ -120,6 +264,39 @@ func closeBasic() error {
 	return nil
 }
 
+// closeRange opens multiple files and closes a range of them via close_range(2).
+func closeRange() error {
+	dir, cleanup, err := makeTempDir("close-range")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	var fds []int
+	for i := range 3 {
+		path := filepath.Join(dir, fmt.Sprintf("closerangefile-%d.txt", i))
+		fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+		if err != nil {
+			return fmt.Errorf("open %d: %w", i, err)
+		}
+		fds = append(fds, fd)
+	}
+
+	if fds[2]-fds[0] != 2 {
+		return fmt.Errorf("fds not contiguous: %v", fds)
+	}
+
+	first := uintptr(fds[0])
+	last := uintptr(fds[len(fds)-1])
+	_, _, errno := syscall.Syscall(sysCloseRange, first, last, 0)
+	if errno != 0 {
+		return fmt.Errorf("close_range: %w", errno)
+	}
+	return nil
+}
+
+const sysCloseRange = 436
+
 // dupBasic opens a file, dups the fd, writes via the dup, closes both.
 func dupBasic() error {
 	dir, cleanup, err := makeTempDir("dup-basic")
@@ -147,6 +324,63 @@ func dupBasic() error {
 	return nil
 }
 
+// dupDup2 opens a file and duplicates the fd onto a specific target fd via dup2.
+func dupDup2() error {
+	dir, cleanup, err := makeTempDir("dup-dup2")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "dup2file.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	// Use a high fd number to avoid collisions.
+	targetFd := 500
+	if err := syscall.Dup2(fd, targetFd); err != nil {
+		return fmt.Errorf("dup2: %w", err)
+	}
+	defer syscall.Close(targetFd)
+
+	if _, err := syscall.Write(targetFd, []byte("via dup2")); err != nil {
+		return fmt.Errorf("write via dup2: %w", err)
+	}
+	return nil
+}
+
+// dupDup3 opens a file and duplicates the fd onto a specific target fd via dup3
+// with O_CLOEXEC flag.
+func dupDup3() error {
+	dir, cleanup, err := makeTempDir("dup-dup3")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "dup3file.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	// Use a high fd number to avoid collisions.
+	targetFd := 501
+	if err := syscall.Dup3(fd, targetFd, syscall.O_CLOEXEC); err != nil {
+		return fmt.Errorf("dup3: %w", err)
+	}
+	defer syscall.Close(targetFd)
+
+	if _, err := syscall.Write(targetFd, []byte("via dup3")); err != nil {
+		return fmt.Errorf("write via dup3: %w", err)
+	}
+	return nil
+}
+
 // fcntlDupfd uses fcntl F_DUPFD to duplicate a file descriptor.
 func fcntlDupfd() error {
 	dir, cleanup, err := makeTempDir("fcntl-dupfd")
@@ -174,7 +408,67 @@ func fcntlDupfd() error {
 	return nil
 }
 
-// renameBasic creates a file and renames it.
+// fcntlSetfl uses fcntl F_GETFL/F_SETFL to read and modify file status flags.
+func fcntlSetfl() error {
+	dir, cleanup, err := makeTempDir("fcntl-setfl")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "fcntlsetflfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	flags, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_GETFL, 0)
+	if errno != 0 {
+		return fmt.Errorf("fcntl F_GETFL: %w", errno)
+	}
+
+	_, _, errno = syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_SETFL, flags|syscall.O_APPEND)
+	if errno != 0 {
+		return fmt.Errorf("fcntl F_SETFL: %w", errno)
+	}
+
+	if _, err := syscall.Write(fd, []byte("appended via fcntl setfl")); err != nil {
+		return fmt.Errorf("write: %w", err)
+	}
+	return nil
+}
+
+// fcntlDupfdCloexec uses fcntl F_DUPFD_CLOEXEC to duplicate a file descriptor
+// with the close-on-exec flag set.
+func fcntlDupfdCloexec() error {
+	dir, cleanup, err := makeTempDir("fcntl-dupfd-cloexec")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "fcntlcloexecfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	newFd, _, errno := syscall.Syscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_DUPFD_CLOEXEC, 0)
+	if errno != 0 {
+		return fmt.Errorf("fcntl F_DUPFD_CLOEXEC: %w", errno)
+	}
+	defer syscall.Close(int(newFd))
+
+	if _, err := syscall.Write(int(newFd), []byte("via fcntl dupfd cloexec")); err != nil {
+		return fmt.Errorf("write via fcntl dup cloexec: %w", err)
+	}
+	return nil
+}
+
+// renameBasic creates a file and renames it via rename(2).
+// Uses raw SYS_RENAME because Go's syscall.Rename wraps renameat on amd64.
 func renameBasic() error {
 	dir, cleanup, err := makeTempDir("rename-basic")
 	if err != nil {
@@ -193,10 +487,138 @@ func renameBasic() error {
 		return fmt.Errorf("close: %w", err)
 	}
 
-	return syscall.Rename(oldPath, newPath)
+	oldBytes, err := syscall.BytePtrFromString(oldPath)
+	if err != nil {
+		return fmt.Errorf("old path bytes: %w", err)
+	}
+	newBytes, err := syscall.BytePtrFromString(newPath)
+	if err != nil {
+		return fmt.Errorf("new path bytes: %w", err)
+	}
+
+	_, _, errno := syscall.Syscall(
+		syscall.SYS_RENAME,
+		uintptr(unsafe.Pointer(oldBytes)),
+		uintptr(unsafe.Pointer(newBytes)),
+		0,
+	)
+	runtime.KeepAlive(oldBytes)
+	runtime.KeepAlive(newBytes)
+	if errno != 0 {
+		return fmt.Errorf("rename: %w", errno)
+	}
+	return nil
+}
+
+// renameRenameat creates a file and renames it via renameat(2).
+func renameRenameat() error {
+	dir, cleanup, err := makeTempDir("rename-renameat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	oldName := "renameat-old.txt"
+	newName := "renameat-new.txt"
+	path := filepath.Join(dir, oldName)
+
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	if err := syscall.Close(fd); err != nil {
+		return fmt.Errorf("close: %w", err)
+	}
+
+	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
+	if err != nil {
+		return fmt.Errorf("open dir: %w", err)
+	}
+	defer syscall.Close(dirFD)
+
+	oldBytes, err := syscall.BytePtrFromString(oldName)
+	if err != nil {
+		return fmt.Errorf("old name bytes: %w", err)
+	}
+	newBytes, err := syscall.BytePtrFromString(newName)
+	if err != nil {
+		return fmt.Errorf("new name bytes: %w", err)
+	}
+
+	_, _, errno := syscall.Syscall6(
+		syscall.SYS_RENAMEAT,
+		uintptr(dirFD),
+		uintptr(unsafe.Pointer(oldBytes)),
+		uintptr(dirFD),
+		uintptr(unsafe.Pointer(newBytes)),
+		0, 0,
+	)
+	runtime.KeepAlive(oldBytes)
+	runtime.KeepAlive(newBytes)
+	if errno != 0 {
+		return fmt.Errorf("renameat: %w", errno)
+	}
+	return nil
+}
+
+const sysRenameat2 = 316 // SYS_RENAMEAT2 on amd64
+
+// renameRenameat2 creates a file and renames it via renameat2(2) with no flags.
+func renameRenameat2() error {
+	dir, cleanup, err := makeTempDir("rename-renameat2")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	oldName := "renameat2-old.txt"
+	newName := "renameat2-new.txt"
+	path := filepath.Join(dir, oldName)
+
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	if err := syscall.Close(fd); err != nil {
+		return fmt.Errorf("close: %w", err)
+	}
+
+	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
+	if err != nil {
+		return fmt.Errorf("open dir: %w", err)
+	}
+	defer syscall.Close(dirFD)
+
+	oldBytes, err := syscall.BytePtrFromString(oldName)
+	if err != nil {
+		return fmt.Errorf("old name bytes: %w", err)
+	}
+	newBytes, err := syscall.BytePtrFromString(newName)
+	if err != nil {
+		return fmt.Errorf("new name bytes: %w", err)
+	}
+
+	_, _, errno := syscall.Syscall6(
+		sysRenameat2,
+		uintptr(dirFD),
+		uintptr(unsafe.Pointer(oldBytes)),
+		uintptr(dirFD),
+		uintptr(unsafe.Pointer(newBytes)),
+		0, // flags=0: plain rename
+		0,
+	)
+	runtime.KeepAlive(oldBytes)
+	runtime.KeepAlive(newBytes)
+	if errno != 0 {
+		return fmt.Errorf("renameat2: %w", errno)
+	}
+	return nil
 }
 
-// linkBasic creates a file, hard links it, and symlinks it.
+// linkBasic creates a file, hard links it via link(2), symlinks it via
+// symlink(2), and reads the symlink via readlink(2).
+// Uses raw SYS_LINK, SYS_SYMLINK, SYS_READLINK because Go's syscall wrappers
+// delegate to linkat/symlinkat/readlinkat on amd64.
 func linkBasic() error {
 	dir, cleanup, err := makeTempDir("link-basic")
 	if err != nil {
@@ -213,24 +635,238 @@ func linkBasic() error {
 		return fmt.Errorf("close: %w", err)
 	}
 
+	// Hard link via raw SYS_LINK.
 	hardPath := filepath.Join(dir, "hardlink.txt")
-	if err := syscall.Link(origPath, hardPath); err != nil {
-		return fmt.Errorf("link: %w", err)
+	origBytes, err := syscall.BytePtrFromString(origPath)
+	if err != nil {
+		return fmt.Errorf("orig path bytes: %w", err)
+	}
+	hardBytes, err := syscall.BytePtrFromString(hardPath)
+	if err != nil {
+		return fmt.Errorf("hard path bytes: %w", err)
+	}
+	_, _, errno := syscall.Syscall(
+		syscall.SYS_LINK,
+		uintptr(unsafe.Pointer(origBytes)),
+		uintptr(unsafe.Pointer(hardBytes)),
+		0,
+	)
+	runtime.KeepAlive(origBytes)
+	runtime.KeepAlive(hardBytes)
+	if errno != 0 {
+		return fmt.Errorf("link: %w", errno)
 	}
 
+	// Symlink via raw SYS_SYMLINK.
 	symPath := filepath.Join(dir, "symlink.txt")
-	if err := syscall.Symlink(origPath, symPath); err != nil {
-		return fmt.Errorf("symlink: %w", err)
+	targetBytes, err := syscall.BytePtrFromString(origPath)
+	if err != nil {
+		return fmt.Errorf("target path bytes: %w", err)
+	}
+	symBytes, err := syscall.BytePtrFromString(symPath)
+	if err != nil {
+		return fmt.Errorf("sym path bytes: %w", err)
+	}
+	_, _, errno = syscall.Syscall(
+		syscall.SYS_SYMLINK,
+		uintptr(unsafe.Pointer(targetBytes)),
+		uintptr(unsafe.Pointer(symBytes)),
+		0,
+	)
+	runtime.KeepAlive(targetBytes)
+	runtime.KeepAlive(symBytes)
+	if errno != 0 {
+		return fmt.Errorf("symlink: %w", errno)
+	}
+
+	// Readlink via raw SYS_READLINK.
+	symBytes2, err := syscall.BytePtrFromString(symPath)
+	if err != nil {
+		return fmt.Errorf("sym path bytes: %w", err)
+	}
+	buf := make([]byte, 256)
+	_, _, errno = syscall.Syscall(
+		syscall.SYS_READLINK,
+		uintptr(unsafe.Pointer(symBytes2)),
+		uintptr(unsafe.Pointer(&buf[0])),
+		uintptr(len(buf)),
+	)
+	runtime.KeepAlive(symBytes2)
+	runtime.KeepAlive(buf)
+	if errno != 0 {
+		return fmt.Errorf("readlink: %w", errno)
+	}
+	return nil
+}
+
+// linkLinkat creates a file and hard links it via linkat(2).
+func linkLinkat() error {
+	dir, cleanup, err := makeTempDir("link-linkat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	origName := "linkat-original.txt"
+	origPath := filepath.Join(dir, origName)
+	fd, err := syscall.Open(origPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	if err := syscall.Close(fd); err != nil {
+		return fmt.Errorf("close: %w", err)
+	}
+
+	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
+	if err != nil {
+		return fmt.Errorf("open dir: %w", err)
+	}
+	defer syscall.Close(dirFD)
+
+	hardName := "linkat-hard.txt"
+	oldBytes, err := syscall.BytePtrFromString(origName)
+	if err != nil {
+		return fmt.Errorf("old name bytes: %w", err)
+	}
+	newBytes, err := syscall.BytePtrFromString(hardName)
+	if err != nil {
+		return fmt.Errorf("new name bytes: %w", err)
+	}
+
+	_, _, errno := syscall.Syscall6(
+		syscall.SYS_LINKAT,
+		uintptr(dirFD),
+		uintptr(unsafe.Pointer(oldBytes)),
+		uintptr(dirFD),
+		uintptr(unsafe.Pointer(newBytes)),
+		0, // flags
+		0,
+	)
+	runtime.KeepAlive(oldBytes)
+	runtime.KeepAlive(newBytes)
+	if errno != 0 {
+		return fmt.Errorf("linkat: %w", errno)
+	}
+	return nil
+}
+
+// linkSymlinkat creates a symlink via symlinkat(2).
+func linkSymlinkat() error {
+	dir, cleanup, err := makeTempDir("link-symlinkat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	origPath := filepath.Join(dir, "symlinkat-original.txt")
+	fd, err := syscall.Open(origPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	if err := syscall.Close(fd); err != nil {
+		return fmt.Errorf("close: %w", err)
+	}
+
+	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
+	if err != nil {
+		return fmt.Errorf("open dir: %w", err)
+	}
+	defer syscall.Close(dirFD)
+
+	targetBytes, err := syscall.BytePtrFromString(origPath)
+	if err != nil {
+		return fmt.Errorf("target bytes: %w", err)
+	}
+	linkName := "symlinkat-link.txt"
+	linkBytes, err := syscall.BytePtrFromString(linkName)
+	if err != nil {
+		return fmt.Errorf("link name bytes: %w", err)
+	}
+
+	_, _, errno := syscall.Syscall(
+		syscall.SYS_SYMLINKAT,
+		uintptr(unsafe.Pointer(targetBytes)),
+		uintptr(dirFD),
+		uintptr(unsafe.Pointer(linkBytes)),
+	)
+	runtime.KeepAlive(targetBytes)
+	runtime.KeepAlive(linkBytes)
+	if errno != 0 {
+		return fmt.Errorf("symlinkat: %w", errno)
+	}
+	return nil
+}
+
+// linkReadlinkat creates a symlink, then reads it via readlinkat(2).
+func linkReadlinkat() error {
+	dir, cleanup, err := makeTempDir("link-readlinkat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	origPath := filepath.Join(dir, "readlinkat-original.txt")
+	fd, err := syscall.Open(origPath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	if err := syscall.Close(fd); err != nil {
+		return fmt.Errorf("close: %w", err)
+	}
+
+	// Create symlink using raw SYS_SYMLINK so we don't mix tracepoints.
+	linkPath := filepath.Join(dir, "readlinkat-link.txt")
+	targetBytes, err := syscall.BytePtrFromString(origPath)
+	if err != nil {
+		return fmt.Errorf("target bytes: %w", err)
+	}
+	linkPathBytes, err := syscall.BytePtrFromString(linkPath)
+	if err != nil {
+		return fmt.Errorf("link path bytes: %w", err)
+	}
+	_, _, errno := syscall.Syscall(
+		syscall.SYS_SYMLINK,
+		uintptr(unsafe.Pointer(targetBytes)),
+		uintptr(unsafe.Pointer(linkPathBytes)),
+		0,
+	)
+	runtime.KeepAlive(targetBytes)
+	runtime.KeepAlive(linkPathBytes)
+	if errno != 0 {
+		return fmt.Errorf("symlink: %w", errno)
 	}
 
+	// Read via readlinkat(2).
+	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
+	if err != nil {
+		return fmt.Errorf("open dir: %w", err)
+	}
+	defer syscall.Close(dirFD)
+
+	linkName := "readlinkat-link.txt"
+	nameBytes, err := syscall.BytePtrFromString(linkName)
+	if err != nil {
+		return fmt.Errorf("link name bytes: %w", err)
+	}
 	buf := make([]byte, 256)
-	if _, err := syscall.Readlink(symPath, buf); err != nil {
-		return fmt.Errorf("readlink: %w", err)
+	_, _, errno = syscall.Syscall6(
+		syscall.SYS_READLINKAT,
+		uintptr(dirFD),
+		uintptr(unsafe.Pointer(nameBytes)),
+		uintptr(unsafe.Pointer(&buf[0])),
+		uintptr(len(buf)),
+		0, 0,
+	)
+	runtime.KeepAlive(nameBytes)
+	runtime.KeepAlive(buf)
+	if errno != 0 {
+		return fmt.Errorf("readlinkat: %w", errno)
 	}
 	return nil
 }
 
-// unlinkBasic creates a file and unlinks it.
+// unlinkBasic creates a file and unlinks it via raw SYS_UNLINK.
+// We use the raw syscall because Go's syscall.Unlink wraps unlinkat on amd64.
 func unlinkBasic() error {
 	dir, cleanup, err := makeTempDir("unlink-basic")
 	if err != nil {
@@ -247,10 +883,82 @@ func unlinkBasic() error {
 		return fmt.Errorf("close: %w", err)
 	}
 
-	return syscall.Unlink(path)
+	pathBytes, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return fmt.Errorf("path bytes: %w", err)
+	}
+	_, _, errno := syscall.Syscall(syscall.SYS_UNLINK, uintptr(unsafe.Pointer(pathBytes)), 0, 0)
+	runtime.KeepAlive(pathBytes)
+	if errno != 0 {
+		return fmt.Errorf("unlink: %w", errno)
+	}
+	return nil
 }
 
-// dirBasic creates a directory, checks access, then removes it.
+// unlinkUnlinkat creates a file and unlinks it via unlinkat(2).
+func unlinkUnlinkat() error {
+	dir, cleanup, err := makeTempDir("unlink-unlinkat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "unlinkat-file.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	if err := syscall.Close(fd); err != nil {
+		return fmt.Errorf("close: %w", err)
+	}
+
+	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
+	if err != nil {
+		return fmt.Errorf("open dir: %w", err)
+	}
+	defer syscall.Close(dirFD)
+
+	nameBytes, err := syscall.BytePtrFromString("unlinkat-file.txt")
+	if err != nil {
+		return fmt.Errorf("name bytes: %w", err)
+	}
+	_, _, errno := syscall.Syscall(syscall.SYS_UNLINKAT, uintptr(dirFD), uintptr(unsafe.Pointer(nameBytes)), 0)
+	runtime.KeepAlive(nameBytes)
+	if errno != 0 {
+		return fmt.Errorf("unlinkat: %w", errno)
+	}
+	return nil
+}
+
+// unlinkRmdir creates a directory and removes it via raw SYS_RMDIR.
+// We use the raw syscall because Go's syscall.Rmdir wraps unlinkat on amd64.
+func unlinkRmdir() error {
+	dir, cleanup, err := makeTempDir("unlink-rmdir")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	subDir := filepath.Join(dir, "rmdir-me")
+	if err := syscall.Mkdir(subDir, 0o755); err != nil {
+		return fmt.Errorf("mkdir: %w", err)
+	}
+
+	pathBytes, err := syscall.BytePtrFromString(subDir)
+	if err != nil {
+		return fmt.Errorf("path bytes: %w", err)
+	}
+	_, _, errno := syscall.Syscall(syscall.SYS_RMDIR, uintptr(unsafe.Pointer(pathBytes)), 0, 0)
+	runtime.KeepAlive(pathBytes)
+	if errno != 0 {
+		return fmt.Errorf("rmdir: %w", errno)
+	}
+	return nil
+}
+
+// dirBasic creates a directory via raw SYS_MKDIR, checks access, then removes it
+// via raw SYS_RMDIR. We use raw syscalls because Go's syscall.Mkdir wraps mkdirat
+// and syscall.Rmdir wraps unlinkat on amd64.
 func dirBasic() error {
 	dir, cleanup, err := makeTempDir("dir-basic")
 	if err != nil {
@@ -259,16 +967,102 @@ func dirBasic() error {
 	defer cleanup()
 
 	subDir := filepath.Join(dir, "subdir")
-	if err := syscall.Mkdir(subDir, 0o755); err != nil {
-		return fmt.Errorf("mkdir: %w", err)
+	pathBytes, err := syscall.BytePtrFromString(subDir)
+	if err != nil {
+		return fmt.Errorf("path bytes: %w", err)
 	}
+	_, _, errno := syscall.Syscall(syscall.SYS_MKDIR, uintptr(unsafe.Pointer(pathBytes)), 0o755, 0)
+	runtime.KeepAlive(pathBytes)
+	if errno != 0 {
+		return fmt.Errorf("mkdir: %w", errno)
+	}
+
 	if err := syscall.Access(subDir, syscall.F_OK); err != nil {
 		return fmt.Errorf("access: %w", err)
 	}
-	return syscall.Rmdir(subDir)
+
+	pathBytes2, err := syscall.BytePtrFromString(subDir)
+	if err != nil {
+		return fmt.Errorf("path bytes: %w", err)
+	}
+	_, _, errno = syscall.Syscall(syscall.SYS_RMDIR, uintptr(unsafe.Pointer(pathBytes2)), 0, 0)
+	runtime.KeepAlive(pathBytes2)
+	if errno != 0 {
+		return fmt.Errorf("rmdir: %w", errno)
+	}
+	return nil
 }
 
-// statBasic creates a file and stats it.
+// dirMkdirat creates a directory via mkdirat(2) using Go's syscall.Mkdir
+// which wraps mkdirat with AT_FDCWD on amd64.
+func dirMkdirat() error {
+	dir, cleanup, err := makeTempDir("dir-mkdirat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	subDir := filepath.Join(dir, "mkdirat-subdir")
+	if err := syscall.Mkdir(subDir, 0o755); err != nil {
+		return fmt.Errorf("mkdirat: %w", err)
+	}
+	return nil
+}
+
+// dirChdir creates a temp directory, then changes to it via chdir(2).
+// Restores the original working directory afterward.
+func dirChdir() error {
+	origDir, err := os.Getwd()
+	if err != nil {
+		return fmt.Errorf("getwd: %w", err)
+	}
+
+	dir, cleanup, err := makeTempDir("dir-chdir")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+	defer syscall.Chdir(origDir)
+
+	if err := syscall.Chdir(dir); err != nil {
+		return fmt.Errorf("chdir: %w", err)
+	}
+	return nil
+}
+
+// dirGetdents opens a directory and reads its entries via getdents64(2).
+func dirGetdents() error {
+	dir, cleanup, err := makeTempDir("dir-getdents")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	// Create a file so getdents has something to return.
+	filePath := filepath.Join(dir, "getdents-file.txt")
+	fd, err := syscall.Open(filePath, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open file: %w", err)
+	}
+	syscall.Close(fd)
+
+	dirFD, err := syscall.Open(dir, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
+	if err != nil {
+		return fmt.Errorf("open dir: %w", err)
+	}
+	defer syscall.Close(dirFD)
+
+	buf := make([]byte, 4096)
+	_, _, errno := syscall.Syscall(syscall.SYS_GETDENTS64, uintptr(dirFD), uintptr(unsafe.Pointer(&buf[0])), uintptr(len(buf)))
+	runtime.KeepAlive(buf)
+	if errno != 0 {
+		return fmt.Errorf("getdents64: %w", errno)
+	}
+	return nil
+}
+
+// statBasic creates a file and stats it via raw SYS_STAT (newstat).
+// We use the raw syscall because Go's syscall.Stat wraps newfstatat on amd64.
 func statBasic() error {
 	dir, cleanup, err := makeTempDir("stat-basic")
 	if err != nil {
@@ -281,14 +1075,191 @@ func statBasic() error {
 	if err != nil {
 		return fmt.Errorf("open: %w", err)
 	}
+	syscall.Close(fd)
+
+	var stat syscall.Stat_t
+	pathBytes, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return fmt.Errorf("path bytes: %w", err)
+	}
+	_, _, errno := syscall.Syscall(syscall.SYS_STAT, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(&stat)), 0)
+	runtime.KeepAlive(pathBytes)
+	runtime.KeepAlive(&stat)
+	if errno != 0 {
+		return fmt.Errorf("stat: %w", errno)
+	}
+	return nil
+}
+
+// statFstat creates a file and stats it via raw SYS_FSTAT (newfstat).
+// This is an fd_event, so ior resolves the path via its fd lookup table.
+func statFstat() error {
+	dir, cleanup, err := makeTempDir("stat-fstat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "fstatfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
 	defer syscall.Close(fd)
 
 	var stat syscall.Stat_t
-	if err := syscall.Fstat(fd, &stat); err != nil {
-		return fmt.Errorf("fstat: %w", err)
+	_, _, errno := syscall.Syscall(syscall.SYS_FSTAT, uintptr(fd), uintptr(unsafe.Pointer(&stat)), 0)
+	runtime.KeepAlive(&stat)
+	if errno != 0 {
+		return fmt.Errorf("fstat: %w", errno)
+	}
+	return nil
+}
+
+// statLstat creates a file and stats it via raw SYS_LSTAT (newlstat).
+// We use the raw syscall because Go's syscall.Lstat wraps newfstatat on amd64.
+func statLstat() error {
+	dir, cleanup, err := makeTempDir("stat-lstat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "lstatfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	syscall.Close(fd)
+
+	var stat syscall.Stat_t
+	pathBytes, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return fmt.Errorf("path bytes: %w", err)
+	}
+	_, _, errno := syscall.Syscall(syscall.SYS_LSTAT, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(&stat)), 0)
+	runtime.KeepAlive(pathBytes)
+	runtime.KeepAlive(&stat)
+	if errno != 0 {
+		return fmt.Errorf("lstat: %w", errno)
 	}
+	return nil
+}
+
+// statNewfstatat creates a file and stats it via Go's syscall.Stat, which
+// wraps SYS_NEWFSTATAT (fstatat with AT_FDCWD) on amd64.
+func statNewfstatat() error {
+	dir, cleanup, err := makeTempDir("stat-newfstatat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "fstatatfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	syscall.Close(fd)
+
+	var stat syscall.Stat_t
 	if err := syscall.Stat(path, &stat); err != nil {
-		return fmt.Errorf("stat: %w", err)
+		return fmt.Errorf("newfstatat: %w", err)
+	}
+	return nil
+}
+
+const (
+	sysStatx       = 332
+	rOK            = 0x4   // R_OK
+	statxBasicMask = 0x07ff // STATX_BASIC_STATS
+)
+
+const atFDCwd = -100 // AT_FDCWD
+
+// statStatx creates a file and stats it via raw statx(2) syscall.
+func statStatx() error {
+	dir, cleanup, err := makeTempDir("stat-statx")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "statxfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	syscall.Close(fd)
+
+	pathBytes, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return fmt.Errorf("path bytes: %w", err)
+	}
+	var buf [256]byte // statx struct is ~256 bytes
+	_, _, errno := syscall.Syscall6(
+		sysStatx,
+		^uintptr(99), // AT_FDCWD (-100)
+		uintptr(unsafe.Pointer(pathBytes)),
+		0,
+		statxBasicMask,
+		uintptr(unsafe.Pointer(&buf[0])),
+		0,
+	)
+	runtime.KeepAlive(pathBytes)
+	runtime.KeepAlive(buf)
+	if errno != 0 {
+		return fmt.Errorf("statx: %w", errno)
+	}
+	return nil
+}
+
+// statAccess creates a file and checks access via raw SYS_ACCESS.
+// We use the raw syscall because Go's syscall.Access wraps faccessat on amd64.
+func statAccess() error {
+	dir, cleanup, err := makeTempDir("stat-access")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "accessfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	syscall.Close(fd)
+
+	pathBytes, err := syscall.BytePtrFromString(path)
+	if err != nil {
+		return fmt.Errorf("path bytes: %w", err)
+	}
+	_, _, errno := syscall.Syscall(syscall.SYS_ACCESS, uintptr(unsafe.Pointer(pathBytes)), rOK, 0)
+	runtime.KeepAlive(pathBytes)
+	if errno != 0 {
+		return fmt.Errorf("access: %w", errno)
+	}
+	return nil
+}
+
+// statFaccessat creates a file and checks access via faccessat(2).
+// Go's syscall.Faccessat wraps SYS_FACCESSAT.
+func statFaccessat() error {
+	dir, cleanup, err := makeTempDir("stat-faccessat")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "faccessatfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	syscall.Close(fd)
+
+	if err := syscall.Faccessat(atFDCwd, path, uint32(rOK), 0); err != nil {
+		return fmt.Errorf("faccessat: %w", err)
 	}
 	return nil
 }
@@ -334,3 +1305,106 @@ func truncateBasic() error {
 	}
 	return syscall.Ftruncate(fd, 5)
 }
+
+// openByHandleAt creates a file, resolves its handle via name_to_handle_at,
+// then opens it via open_by_handle_at. Requires root (CAP_DAC_READ_SEARCH).
+// LockOSThread prevents goroutine migration between the two syscalls so that
+// ior sees the same TID for both and can correlate the path.
+func openByHandleAt() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	dir, cleanup, err := makeTempDir("open-by-handle-at")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "handlefile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	if err := syscall.Close(fd); err != nil {
+		return fmt.Errorf("close: %w", err)
+	}
+
+	handle, mountFD, err := nameToHandleAt(dir, "handlefile.txt")
+	if err != nil {
+		return fmt.Errorf("name_to_handle_at: %w", err)
+	}
+	defer syscall.Close(mountFD)
+
+	fd2, err := openByHandleAtSyscall(mountFD, handle, syscall.O_RDONLY)
+	if err != nil {
+		return fmt.Errorf("open_by_handle_at: %w", err)
+	}
+	return syscall.Close(fd2)
+}
+
+// fileHandle matches the kernel's struct file_handle layout.
+type fileHandle struct {
+	Size uint32
+	Type int32
+	// Handle bytes follow immediately after.
+}
+
+const (
+	sysNameToHandleAt = 303
+	sysOpenByHandleAt = 304
+)
+
+// nameToHandleAt calls name_to_handle_at(2) and returns the file handle
+// and the directory fd. The caller can pass this dirFD as the mount_fd
+// argument to open_by_handle_at since any fd on the same filesystem works.
+func nameToHandleAt(dirPath, name string) ([]byte, int, error) {
+	dirFD, err := syscall.Open(dirPath, syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
+	if err != nil {
+		return nil, 0, fmt.Errorf("open dir: %w", err)
+	}
+
+	nameBytes, err := syscall.BytePtrFromString(name)
+	if err != nil {
+		syscall.Close(dirFD)
+		return nil, 0, fmt.Errorf("name bytes: %w", err)
+	}
+
+	// Start with a buffer large enough for most handles.
+	buf := make([]byte, unsafe.Sizeof(fileHandle{})+128)
+	fh := (*fileHandle)(unsafe.Pointer(&buf[0]))
+	fh.Size = uint32(len(buf) - int(unsafe.Sizeof(fileHandle{})))
+
+	var mountID int32
+	_, _, errno := syscall.Syscall6(
+		sysNameToHandleAt,
+		uintptr(dirFD),
+		uintptr(unsafe.Pointer(nameBytes)),
+		uintptr(unsafe.Pointer(fh)),
+		uintptr(unsafe.Pointer(&mountID)),
+		0, 0,
+	)
+	if errno != 0 {
+		syscall.Close(dirFD)
+		return nil, 0, fmt.Errorf("syscall: %w", errno)
+	}
+
+	handleLen := int(unsafe.Sizeof(fileHandle{})) + int(fh.Size)
+	handle := make([]byte, handleLen)
+	copy(handle, buf[:handleLen])
+
+	return handle, dirFD, nil
+}
+
+// openByHandleAtSyscall calls open_by_handle_at(2).
+func openByHandleAtSyscall(mountFD int, handle []byte, flags int) (int, error) {
+	fd, _, errno := syscall.Syscall(
+		sysOpenByHandleAt,
+		uintptr(mountFD),
+		uintptr(unsafe.Pointer(&handle[0])),
+		uintptr(flags),
+	)
+	if errno != 0 {
+		return 0, fmt.Errorf("syscall: %w", errno)
+	}
+	return int(fd), nil
+}