[syserror] Add conversions to linuxerr with temporary Equals method.

Add Equals method to compare syserror and unix.Errno errors to linuxerr errors.
This will facilitate removal of syserror definitions in a followup, and
finding needed conversions from unix.Errno to linuxerr.

PiperOrigin-RevId: 380909667

4 files changed, 7 insertions, 4 deletions

diff --git a/pkg/sentry/fs/host/BUILD b/pkg/sentry/fs/host/BUILD
index 3c45f6cc5..52de3875d 100644
--- a/pkg/sentry/fs/host/BUILD
+++ b/pkg/sentry/fs/host/BUILD
@@ -28,6 +28,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/errors/linuxerr",
         "//pkg/fd",
         "//pkg/fdnotifier",
         "//pkg/iovec",
diff --git a/pkg/sentry/fs/host/socket.go b/pkg/sentry/fs/host/socket.go
index 46a2dc47d..225244868 100644
--- a/pkg/sentry/fs/host/socket.go
+++ b/pkg/sentry/fs/host/socket.go
@@ -21,6 +21,7 @@ import (
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/errors/linuxerr"
 	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/fdnotifier"
 	"gvisor.dev/gvisor/pkg/refs"
@@ -213,7 +214,7 @@ func (c *ConnectedEndpoint) Send(ctx context.Context, data [][]byte, controlMess
 		// block (and only for stream sockets).
 		err = syserror.EAGAIN
 	}
-	if n > 0 && err != syserror.EAGAIN {
+	if n > 0 && !linuxerr.Equals(linuxerr.EAGAIN, err) {
 		// The caller may need to block to send more data, but
 		// otherwise there isn't anything that can be done about an
 		// error with a partial write.
diff --git a/pkg/sentry/fs/host/tty.go b/pkg/sentry/fs/host/tty.go
index 1183727ab..77613bfd5 100644
--- a/pkg/sentry/fs/host/tty.go
+++ b/pkg/sentry/fs/host/tty.go
@@ -17,6 +17,7 @@ package host
 import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/errors/linuxerr"
 	"gvisor.dev/gvisor/pkg/marshal/primitive"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -191,7 +192,7 @@ func (t *TTYFileOperations) Ioctl(ctx context.Context, _ *fs.File, io usermem.IO
 		if err := t.checkChange(ctx, linux.SIGTTOU); err != nil {
 			// drivers/tty/tty_io.c:tiocspgrp() converts -EIO from
 			// tty_check_change() to -ENOTTY.
-			if err == syserror.EIO {
+			if linuxerr.Equals(linuxerr.EIO, err) {
 				return 0, syserror.ENOTTY
 			}
 			return 0, err
diff --git a/pkg/sentry/fs/host/util.go b/pkg/sentry/fs/host/util.go
index ab74724a3..e7db79189 100644
--- a/pkg/sentry/fs/host/util.go
+++ b/pkg/sentry/fs/host/util.go
@@ -19,12 +19,12 @@ import (
 
 	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/errors/linuxerr"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/device"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
-	"gvisor.dev/gvisor/pkg/syserror"
 )
 
 func nodeType(s *unix.Stat_t) fs.InodeType {
@@ -98,7 +98,7 @@ type dirInfo struct {
 // isBlockError unwraps os errors and checks if they are caused by EAGAIN or
 // EWOULDBLOCK. This is so they can be transformed into syserror.ErrWouldBlock.
 func isBlockError(err error) bool {
-	if err == syserror.EAGAIN || err == syserror.EWOULDBLOCK {
+	if linuxerr.Equals(linuxerr.EAGAIN, err) || linuxerr.Equals(linuxerr.EWOULDBLOCK, err) {
 		return true
 	}
 	if pe, ok := err.(*os.PathError); ok {