mirror of https://github.com/ceph/go-ceph
cephfs: implement file IO functions for open/close/read/write/seek
Implement core file I/O functions based on a file handle wrapper. Signed-off-by: John Mulligan <jmulligan@redhat.com>
This commit is contained in:
John Mulligan
Niels de Vos
parent
fb2736dd0a
commit
854a834b1c
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@ -38,4 +38,6 @@ func getError(e C.int) error {
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const (
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errNameTooLong = CephFSError(-C.ENAMETOOLONG)
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errInvalid = CephFSError(-C.EINVAL)
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)
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@ -0,0 +1,133 @@
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package cephfs
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/*
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#cgo LDFLAGS: -lcephfs
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#cgo CPPFLAGS: -D_FILE_OFFSET_BITS=64
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#include <stdlib.h>
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#include <cephfs/libcephfs.h>
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*/
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import "C"
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import (
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"unsafe"
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)
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const (
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// SeekSet is used with Seek to set the absolute position in the file.
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SeekSet = int(C.SEEK_SET)
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// SeekCur is used with Seek to position the file relative to the current
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// position.
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SeekCur = int(C.SEEK_CUR)
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// SeekEnd is used with Seek to position the file relative to the end.
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SeekEnd = int(C.SEEK_END)
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)
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// File represents an open file descriptor in cephfs.
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type File struct {
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mount *MountInfo
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fd C.int
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}
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// Open a file at the given path. The flags are the same os flags as
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// a local open call. Mode is the same mode bits as a local open call.
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//
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// Implements:
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// int ceph_open(struct ceph_mount_info *cmount, const char *path, int flags, mode_t mode);
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func (mount *MountInfo) Open(path string, flags int, mode uint32) (*File, error) {
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cPath := C.CString(path)
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defer C.free(unsafe.Pointer(cPath))
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ret := C.ceph_open(mount.mount, cPath, C.int(flags), C.mode_t(mode))
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if ret < 0 {
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return nil, getError(ret)
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}
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return &File{mount: mount, fd: ret}, nil
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}
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// Close the file.
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//
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// Implements:
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// int ceph_close(struct ceph_mount_info *cmount, int fd);
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func (f *File) Close() error {
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return getError(C.ceph_close(f.mount.mount, f.fd))
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}
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// read directly wraps the ceph_read call. Because read is such a common
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// operation we deviate from the ceph naming and expose Read and ReadAt
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// wrappers for external callers of the library.
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//
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// Implements:
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// int ceph_read(struct ceph_mount_info *cmount, int fd, char *buf, int64_t size, int64_t offset);
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func (f *File) read(buf []byte, offset int64) (int, error) {
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bufptr := (*C.char)(unsafe.Pointer(&buf[0]))
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ret := C.ceph_read(
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f.mount.mount, f.fd, bufptr, C.int64_t(len(buf)), C.int64_t(offset))
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if ret < 0 {
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return int(ret), getError(ret)
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}
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return int(ret), nil
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}
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// Read data from file. Up to len(buf) bytes will be read from the file.
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// The number of bytes read will be returned.
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func (f *File) Read(buf []byte) (int, error) {
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// to-consider: should we mimic Go's behavior of returning an
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// io.ErrShortWrite error if write length < buf size?
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return f.read(buf, -1)
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}
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// ReadAt will read data from the file starting at the given offset.
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// Up to len(buf) bytes will be read from the file.
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// The number of bytes read will be returned.
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func (f *File) ReadAt(buf []byte, offset int64) (int, error) {
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return f.read(buf, offset)
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}
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// write directly wraps the ceph_write call. Because write is such a common
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// operation we deviate from the ceph naming and expose Write and WriteAt
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// wrappers for external callers of the library.
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//
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// Implements:
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// int ceph_write(struct ceph_mount_info *cmount, int fd, const char *buf,
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// int64_t size, int64_t offset);
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func (f *File) write(buf []byte, offset int64) (int, error) {
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bufptr := (*C.char)(unsafe.Pointer(&buf[0]))
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ret := C.ceph_write(
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f.mount.mount, f.fd, bufptr, C.int64_t(len(buf)), C.int64_t(offset))
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if ret < 0 {
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return 0, getError(ret)
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}
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return int(ret), nil
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}
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// Write data from buf to the file.
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// The number of bytes written is returned.
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func (f *File) Write(buf []byte) (int, error) {
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return f.write(buf, -1)
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}
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// WriteAt writes data from buf to the file at the specified offset.
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// The number of bytes written is returned.
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func (f *File) WriteAt(buf []byte, offset int64) (int, error) {
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return f.write(buf, offset)
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}
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// Seek will reposition the file stream based on the given offset.
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//
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// Implements:
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// int64_t ceph_lseek(struct ceph_mount_info *cmount, int fd, int64_t offset, int whence);
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func (f *File) Seek(offset int64, whence int) (int64, error) {
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// validate the seek whence value in case the caller skews
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// from the seek values we technically support from C as documented.
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// TODO: need to support seek-(hole|data) in mimic and later.
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switch whence {
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case SeekSet, SeekCur, SeekEnd:
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default:
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return 0, errInvalid
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}
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ret := C.ceph_lseek(f.mount.mount, f.fd, C.int64_t(offset), C.int(whence))
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if ret < 0 {
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return 0, getError(C.int(ret))
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}
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return int64(ret), nil
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}
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@ -0,0 +1,216 @@
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package cephfs
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import (
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"io"
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"os"
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"path"
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"testing"
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"github.com/stretchr/testify/assert"
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)
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func TestFileOpen(t *testing.T) {
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mount := fsConnect(t)
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defer fsDisconnect(t, mount)
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fname := "TestFileOpen.txt"
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// idempotent open for read and write
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t.Run("create", func(t *testing.T) {
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f1, err := mount.Open(fname, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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assert.NotNil(t, f1)
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err = f1.Close()
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assert.NoError(t, err)
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// TODO: clean up file
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})
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t.Run("errorMissing", func(t *testing.T) {
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// try to open a file we know should not exist
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f2, err := mount.Open(".nope", os.O_RDONLY, 0666)
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assert.Error(t, err)
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assert.Nil(t, f2)
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})
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t.Run("existsInMount", func(t *testing.T) {
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useMount(t)
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f1, err := mount.Open(fname, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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assert.NotNil(t, f1)
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err = f1.Close()
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assert.NoError(t, err)
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s, err := os.Stat(path.Join(CephMountDir, fname))
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assert.NoError(t, err)
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assert.EqualValues(t, 0, s.Size())
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})
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}
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func TestFileReadWrite(t *testing.T) {
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mount := fsConnect(t)
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defer fsDisconnect(t, mount)
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fname := "TestFileReadWrite.txt"
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t.Run("writeAndRead", func(t *testing.T) {
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// idempotent open for read and write
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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n, err := f1.Write([]byte("yello world!"))
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assert.NoError(t, err)
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assert.EqualValues(t, 12, n)
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err = f1.Close()
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assert.NoError(t, err)
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buf := make([]byte, 1024)
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f2, err := mount.Open(fname, os.O_RDONLY, 0)
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n, err = f2.Read(buf)
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assert.NoError(t, err)
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assert.EqualValues(t, 12, n)
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assert.Equal(t, "yello world!", string(buf[:n]))
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})
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t.Run("openForWriteOnly", func(t *testing.T) {
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buf := make([]byte, 32)
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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defer func() { assert.NoError(t, f1.Close()) }()
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_, err = f1.Read(buf)
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assert.Error(t, err)
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})
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t.Run("openForReadOnly", func(t *testing.T) {
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// "touch" the file
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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assert.NoError(t, f1.Close())
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f1, err = mount.Open(fname, os.O_RDONLY, 0666)
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assert.NoError(t, err)
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defer func() { assert.NoError(t, f1.Close()) }()
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_, err = f1.Write([]byte("yo"))
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assert.Error(t, err)
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})
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}
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func TestFileReadWriteAt(t *testing.T) {
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mount := fsConnect(t)
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defer fsDisconnect(t, mount)
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fname := "TestFileReadWriteAt.txt"
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t.Run("writeAtAndReadAt", func(t *testing.T) {
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// idempotent open for read and write
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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n, err := f1.WriteAt([]byte("foo"), 0)
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assert.NoError(t, err)
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assert.EqualValues(t, 3, n)
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n, err = f1.WriteAt([]byte("bar"), 6)
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assert.NoError(t, err)
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assert.EqualValues(t, 3, n)
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err = f1.Close()
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assert.NoError(t, err)
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buf := make([]byte, 4)
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f2, err := mount.Open(fname, os.O_RDONLY, 0)
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n, err = f2.ReadAt(buf, 0)
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assert.NoError(t, err)
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assert.EqualValues(t, 4, n)
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assert.Equal(t, "foo", string(buf[:3]))
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assert.EqualValues(t, 0, string(buf[3]))
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n, err = f2.ReadAt(buf, 6)
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assert.NoError(t, err)
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assert.EqualValues(t, 3, n)
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assert.Equal(t, "bar", string(buf[:3]))
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})
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t.Run("openForWriteOnly", func(t *testing.T) {
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buf := make([]byte, 32)
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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defer func() { assert.NoError(t, f1.Close()) }()
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_, err = f1.ReadAt(buf, 0)
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assert.Error(t, err)
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})
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t.Run("openForReadOnly", func(t *testing.T) {
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// "touch" the file
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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assert.NoError(t, f1.Close())
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f1, err = mount.Open(fname, os.O_RDONLY, 0666)
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assert.NoError(t, err)
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defer func() { assert.NoError(t, f1.Close()) }()
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_, err = f1.WriteAt([]byte("yo"), 0)
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assert.Error(t, err)
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})
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}
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func TestFileInterfaces(t *testing.T) {
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mount := fsConnect(t)
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defer fsDisconnect(t, mount)
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fname := "TestFileInterfaces.txt"
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t.Run("ioWriter", func(t *testing.T) {
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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defer func() { assert.NoError(t, f1.Close()) }()
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var w io.Writer = f1
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_, err = w.Write([]byte("foo"))
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assert.NoError(t, err)
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})
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t.Run("ioReader", func(t *testing.T) {
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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assert.NoError(t, f1.Close())
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f1, err = mount.Open(fname, os.O_RDONLY, 0666)
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assert.NoError(t, err)
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defer func() { assert.NoError(t, f1.Close()) }()
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var r io.Reader = f1
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buf := make([]byte, 32)
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_, err = r.Read(buf)
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assert.NoError(t, err)
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})
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}
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func TestFileSeek(t *testing.T) {
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mount := fsConnect(t)
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defer fsDisconnect(t, mount)
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fname := "TestFileSeek.txt"
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t.Run("validSeek", func(t *testing.T) {
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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defer func() { assert.NoError(t, f1.Close()) }()
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o, err := f1.Seek(8, SeekSet)
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assert.NoError(t, err)
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assert.EqualValues(t, 8, o)
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n, err := f1.Write([]byte("flimflam"))
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assert.NoError(t, err)
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assert.EqualValues(t, 8, n)
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})
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t.Run("invalidWhence", func(t *testing.T) {
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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defer func() { assert.NoError(t, f1.Close()) }()
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o, err := f1.Seek(8, 1776)
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assert.Error(t, err)
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assert.EqualValues(t, 0, o)
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})
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t.Run("invalidSeek", func(t *testing.T) {
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f1, err := mount.Open(fname, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
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assert.NoError(t, err)
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defer func() { assert.NoError(t, f1.Close()) }()
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o, err := f1.Seek(-22, SeekSet)
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assert.Error(t, err)
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assert.EqualValues(t, 0, o)
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})
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}
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