diff options
| -rw-r--r-- | runsc/boot/loader.go | 45 |
1 files changed, 40 insertions, 5 deletions
diff --git a/runsc/boot/loader.go b/runsc/boot/loader.go index e7ca98134..654441f65 100644 --- a/runsc/boot/loader.go +++ b/runsc/boot/loader.go @@ -156,13 +156,17 @@ type Args struct { Spec *specs.Spec // Conf is the system configuration. Conf *Config - // ControllerFD is the FD to the URPC controller. + // ControllerFD is the FD to the URPC controller. The Loader takes ownership + // of this FD and may close it at any time. ControllerFD int - // Device is an optional argument that is passed to the platform. + // Device is an optional argument that is passed to the platform. The Loader + // takes ownership of this file and may close it at any time. Device *os.File - // GoferFDs is an array of FDs used to connect with the Gofer. + // GoferFDs is an array of FDs used to connect with the Gofer. The Loader + // takes ownership of these FDs and may close them at any time. GoferFDs []int - // StdioFDs is the stdio for the application. + // StdioFDs is the stdio for the application. The Loader takes ownership of + // these FDs and may close them at any time. StdioFDs []int // Console is set to true if using TTY. Console bool @@ -175,6 +179,9 @@ type Args struct { UserLogFD int } +// make sure stdioFDs are always the same on initial start and on restore +const startingStdioFD = 64 + // New initializes a new kernel loader configured by spec. // New also handles setting up a kernel for restoring a container. func New(args Args) (*Loader, error) { @@ -319,6 +326,24 @@ func New(args Args) (*Loader, error) { return nil, fmt.Errorf("creating pod mount hints: %v", err) } + // Make host FDs stable between invocations. Host FDs must map to the exact + // same number when the sandbox is restored. Otherwise the wrong FD will be + // used. + var stdioFDs []int + newfd := startingStdioFD + for _, fd := range args.StdioFDs { + err := syscall.Dup3(fd, newfd, syscall.O_CLOEXEC) + if err != nil { + return nil, fmt.Errorf("dup3 of stdioFDs failed: %v", err) + } + stdioFDs = append(stdioFDs, newfd) + err = syscall.Close(fd) + if err != nil { + return nil, fmt.Errorf("close original stdioFDs failed: %v", err) + } + newfd++ + } + eid := execID{cid: args.ID} l := &Loader{ k: k, @@ -327,7 +352,7 @@ func New(args Args) (*Loader, error) { watchdog: dog, spec: args.Spec, goferFDs: args.GoferFDs, - stdioFDs: args.StdioFDs, + stdioFDs: stdioFDs, rootProcArgs: procArgs, sandboxID: args.ID, processes: map[execID]*execProcess{eid: {}}, @@ -569,6 +594,16 @@ func (l *Loader) run() error { } }) + // l.stdioFDs are derived from dup() in boot.New() and they are now dup()ed again + // either in createFDTable() during initial start or in descriptor.initAfterLoad() + // during restore, we can release l.stdioFDs now. + for _, fd := range l.stdioFDs { + err := syscall.Close(fd) + if err != nil { + return fmt.Errorf("close dup()ed stdioFDs: %v", err) + } + } + log.Infof("Process should have started...") l.watchdog.Start() return l.k.Start() |