diff options
Diffstat (limited to 'runsc/fsgofer/fsgofer.go')
| -rw-r--r-- | runsc/fsgofer/fsgofer.go | 70 |
1 files changed, 54 insertions, 16 deletions
diff --git a/runsc/fsgofer/fsgofer.go b/runsc/fsgofer/fsgofer.go index ed8b02cf0..b59e1a70e 100644 --- a/runsc/fsgofer/fsgofer.go +++ b/runsc/fsgofer/fsgofer.go @@ -199,6 +199,7 @@ func (a *attachPoint) makeQID(stat syscall.Stat_t) p9.QID { // The reason that the file is not opened initially as read-write is for better // performance with 'overlay2' storage driver. overlay2 eagerly copies the // entire file up when it's opened in write mode, and would perform badly when +// multiple files are only being opened for read (esp. startup). type localFile struct { p9.DefaultWalkGetAttr @@ -265,10 +266,10 @@ func openAnyFileFromParent(parent *localFile, name string) (*fd.FD, string, erro // actual file open and is customizable by the caller. func openAnyFile(path string, fn func(mode int) (*fd.FD, error)) (*fd.FD, error) { // Attempt to open file in the following mode in order: - // 1. RDONLY | NONBLOCK: for all files, works for directories and ro mounts too. - // Use non-blocking to prevent getting stuck inside open(2) for FIFOs. This option - // has no effect on regular files. - // 2. PATH: for symlinks + // 1. RDONLY | NONBLOCK: for all files, directories, ro mounts, FIFOs. + // Use non-blocking to prevent getting stuck inside open(2) for + // FIFOs. This option has no effect on regular files. + // 2. PATH: for symlinks, sockets. modes := []int{syscall.O_RDONLY | syscall.O_NONBLOCK, unix.O_PATH} var err error @@ -366,23 +367,24 @@ func fchown(fd int, uid p9.UID, gid p9.GID) error { } // Open implements p9.File. -func (l *localFile) Open(mode p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) { +func (l *localFile) Open(flags p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) { if l.isOpen() { panic(fmt.Sprintf("attempting to open already opened file: %q", l.hostPath)) } // Check if control file can be used or if a new open must be created. var newFile *fd.FD - if mode == p9.ReadOnly { - log.Debugf("Open reusing control file, mode: %v, %q", mode, l.hostPath) + if flags == p9.ReadOnly { + log.Debugf("Open reusing control file, flags: %v, %q", flags, l.hostPath) newFile = l.file } else { // Ideally reopen would call name_to_handle_at (with empty name) and // open_by_handle_at to reopen the file without using 'hostPath'. However, // name_to_handle_at and open_by_handle_at aren't supported by overlay2. - log.Debugf("Open reopening file, mode: %v, %q", mode, l.hostPath) + log.Debugf("Open reopening file, flags: %v, %q", flags, l.hostPath) var err error - newFile, err = reopenProcFd(l.file, openFlags|mode.OSFlags()) + // Constrain open flags to the open mode and O_TRUNC. + newFile, err = reopenProcFd(l.file, openFlags|(flags.OSFlags()&(syscall.O_ACCMODE|syscall.O_TRUNC))) if err != nil { return nil, p9.QID{}, 0, extractErrno(err) } @@ -409,7 +411,7 @@ func (l *localFile) Open(mode p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) { } l.file = newFile } - l.mode = mode + l.mode = flags & p9.OpenFlagsModeMask return fd, l.attachPoint.makeQID(stat), 0, nil } @@ -601,7 +603,7 @@ func (l *localFile) GetAttr(_ p9.AttrMask) (p9.QID, p9.AttrMask, p9.Attr, error) Mode: p9.FileMode(stat.Mode), UID: p9.UID(stat.Uid), GID: p9.GID(stat.Gid), - NLink: stat.Nlink, + NLink: uint64(stat.Nlink), RDev: stat.Rdev, Size: uint64(stat.Size), BlockSize: uint64(stat.Blksize), @@ -955,14 +957,14 @@ func (l *localFile) Readdir(offset uint64, count uint32) ([]p9.Dirent, error) { } func (l *localFile) readDirent(f int, offset uint64, count uint32, skip uint64) ([]p9.Dirent, error) { + var dirents []p9.Dirent + // Limit 'count' to cap the slice size that is returned. const maxCount = 100000 if count > maxCount { count = maxCount } - dirents := make([]p9.Dirent, 0, count) - // Pre-allocate buffers that will be reused to get partial results. direntsBuf := make([]byte, 8192) names := make([]string, 0, 100) @@ -1032,12 +1034,48 @@ func (l *localFile) Flush() error { } // Connect implements p9.File. -func (l *localFile) Connect(p9.ConnectFlags) (*fd.FD, error) { - // Check to see if the CLI option has been set to allow the UDS mount. +func (l *localFile) Connect(flags p9.ConnectFlags) (*fd.FD, error) { if !l.attachPoint.conf.HostUDS { return nil, syscall.ECONNREFUSED } - return fd.DialUnix(l.hostPath) + + // TODO(gvisor.dev/issue/1003): Due to different app vs replacement + // mappings, the app path may have fit in the sockaddr, but we can't + // fit f.path in our sockaddr. We'd need to redirect through a shorter + // path in order to actually connect to this socket. + if len(l.hostPath) > linux.UnixPathMax { + return nil, syscall.ECONNREFUSED + } + + var stype int + switch flags { + case p9.StreamSocket: + stype = syscall.SOCK_STREAM + case p9.DgramSocket: + stype = syscall.SOCK_DGRAM + case p9.SeqpacketSocket: + stype = syscall.SOCK_SEQPACKET + default: + return nil, syscall.ENXIO + } + + f, err := syscall.Socket(syscall.AF_UNIX, stype, 0) + if err != nil { + return nil, err + } + + if err := syscall.SetNonblock(f, true); err != nil { + syscall.Close(f) + return nil, err + } + + sa := syscall.SockaddrUnix{Name: l.hostPath} + if err := syscall.Connect(f, &sa); err != nil { + syscall.Close(f) + return nil, err + } + + return fd.New(f), nil } // Close implements p9.File. |