Merge release-20210806.0-29-gce58d71fd (automated)

1 files changed, 120 insertions, 0 deletions

diff --git a/pkg/errors/linuxerr/internal.go b/pkg/errors/linuxerr/internal.go
new file mode 100644
index 000000000..127bba0df
--- /dev/null
+++ b/pkg/errors/linuxerr/internal.go
@@ -0,0 +1,120 @@
+// Copyright 2021 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License"),;
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package linuxerr
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux/errno"
+	"gvisor.dev/gvisor/pkg/errors"
+)
+
+var (
+	// ErrWouldBlock is an internal error used to indicate that an operation
+	// cannot be satisfied immediately, and should be retried at a later
+	// time, possibly when the caller has received a notification that the
+	// operation may be able to complete. It is used by implementations of
+	// the kio.File interface.
+	ErrWouldBlock = errors.New(errno.EWOULDBLOCK, "request would block")
+
+	// ErrInterrupted is returned if a request is interrupted before it can
+	// complete.
+	ErrInterrupted = errors.New(errno.EINTR, "request was interrupted")
+
+	// ErrExceedsFileSizeLimit is returned if a request would exceed the
+	// file's size limit.
+	ErrExceedsFileSizeLimit = errors.New(errno.E2BIG, "exceeds file size limit")
+)
+
+var errorMap = map[error]*errors.Error{
+	ErrWouldBlock:           EWOULDBLOCK,
+	ErrInterrupted:          EINTR,
+	ErrExceedsFileSizeLimit: EFBIG,
+}
+
+// errorUnwrappers is an array of unwrap functions to extract typed errors.
+var errorUnwrappers = []func(error) (*errors.Error, bool){}
+
+// AddErrorUnwrapper registers an unwrap method that can extract a concrete error
+// from a typed, but not initialized, error.
+func AddErrorUnwrapper(unwrap func(e error) (*errors.Error, bool)) {
+	errorUnwrappers = append(errorUnwrappers, unwrap)
+}
+
+// TranslateError translates errors to errnos, it will return false if
+// the error was not registered.
+func TranslateError(from error) (*errors.Error, bool) {
+	if err, ok := errorMap[from]; ok {
+		return err, true
+	}
+	// Try to unwrap the error if we couldn't match an error
+	// exactly.  This might mean that a package has its own
+	// error type.
+	for _, unwrap := range errorUnwrappers {
+		if err, ok := unwrap(from); ok {
+			return err, true
+		}
+	}
+	return nil, false
+}
+
+// These errors are significant because ptrace syscall exit tracing can
+// observe them.
+//
+// For all of the following errors, if the syscall is not interrupted by a
+// signal delivered to a user handler, the syscall is restarted.
+var (
+	// ERESTARTSYS is returned by an interrupted syscall to indicate that it
+	// should be converted to EINTR if interrupted by a signal delivered to a
+	// user handler without SA_RESTART set, and restarted otherwise.
+	ERESTARTSYS = errors.New(errno.ERESTARTSYS, "to be restarted if SA_RESTART is set")
+
+	// ERESTARTNOINTR is returned by an interrupted syscall to indicate that it
+	// should always be restarted.
+	ERESTARTNOINTR = errors.New(errno.ERESTARTNOINTR, "to be restarted")
+
+	// ERESTARTNOHAND is returned by an interrupted syscall to indicate that it
+	// should be converted to EINTR if interrupted by a signal delivered to a
+	// user handler, and restarted otherwise.
+	ERESTARTNOHAND = errors.New(errno.ERESTARTNOHAND, "to be restarted if no handler")
+
+	// ERESTART_RESTARTBLOCK is returned by an interrupted syscall to indicate
+	// that it should be restarted using a custom function. The interrupted
+	// syscall must register a custom restart function by calling
+	// Task.SetRestartSyscallFn.
+	ERESTART_RESTARTBLOCK = errors.New(errno.ERESTART_RESTARTBLOCK, "interrupted by signal")
+)
+
+var restartMap = map[int]*errors.Error{
+	-int(errno.ERESTARTSYS):           ERESTARTSYS,
+	-int(errno.ERESTARTNOINTR):        ERESTARTNOINTR,
+	-int(errno.ERESTARTNOHAND):        ERESTARTNOHAND,
+	-int(errno.ERESTART_RESTARTBLOCK): ERESTART_RESTARTBLOCK,
+}
+
+// IsRestartError checks if a given error is a restart error.
+func IsRestartError(err error) bool {
+	switch err {
+	case ERESTARTSYS, ERESTARTNOINTR, ERESTARTNOHAND, ERESTART_RESTARTBLOCK:
+		return true
+	default:
+		return false
+	}
+}
+
+// SyscallRestartErrorFromReturn returns the SyscallRestartErrno represented by
+// rv, the value in a syscall return register.
+func SyscallRestartErrorFromReturn(rv uintptr) (*errors.Error, bool) {
+	err, ok := restartMap[int(rv)]
+	return err, ok
+}