[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

3 files changed, 13 insertions, 11 deletions

diff --git a/runsc/boot/BUILD b/runsc/boot/BUILD
index a79afbdc4..c7b26746b 100644
--- a/runsc/boot/BUILD
+++ b/runsc/boot/BUILD
@@ -32,6 +32,7 @@ go_library(
         "//pkg/control/server",
         "//pkg/coverage",
         "//pkg/cpuid",
+        "//pkg/errors/linuxerr",
         "//pkg/eventchannel",
         "//pkg/fd",
         "//pkg/flipcall",
diff --git a/runsc/boot/fs.go b/runsc/boot/fs.go
index c4590aab1..7fce2b708 100644
--- a/runsc/boot/fs.go
+++ b/runsc/boot/fs.go
@@ -25,6 +25,7 @@ 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/log"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
@@ -41,7 +42,6 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
-	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/runsc/config"
 	"gvisor.dev/gvisor/runsc/specutils"
 
@@ -1039,8 +1039,8 @@ func (c *containerMounter) mountTmp(ctx context.Context, conf *config.Config, mn
 
 	maxTraversals := uint(0)
 	tmp, err := mns.FindInode(ctx, root, root, "tmp", &maxTraversals)
-	switch err {
-	case nil:
+	switch {
+	case err == nil:
 		// Found '/tmp' in filesystem, check if it's empty.
 		defer tmp.DecRef(ctx)
 		f, err := tmp.Inode.GetFile(ctx, tmp, fs.FileFlags{Read: true, Directory: true})
@@ -1061,7 +1061,7 @@ func (c *containerMounter) mountTmp(ctx context.Context, conf *config.Config, mn
 		log.Infof("Mounting internal tmpfs on top of empty %q", "/tmp")
 		fallthrough
 
-	case syserror.ENOENT:
+	case linuxerr.Equals(linuxerr.ENOENT, err):
 		// No '/tmp' found (or fallthrough from above). Safe to mount internal
 		// tmpfs.
 		tmpMount := specs.Mount{
diff --git a/runsc/boot/vfs.go b/runsc/boot/vfs.go
index 52aa33529..ca1a86e39 100644
--- a/runsc/boot/vfs.go
+++ b/runsc/boot/vfs.go
@@ -24,6 +24,7 @@ import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/cleanup"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/errors/linuxerr"
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/devices/memdev"
@@ -656,8 +657,8 @@ func (c *containerMounter) mountTmpVFS2(ctx context.Context, conf *config.Config
 		Path:  fspath.Parse("/tmp"),
 	}
 	fd, err := c.k.VFS().OpenAt(ctx, creds, &pop, &vfs.OpenOptions{Flags: linux.O_RDONLY | linux.O_DIRECTORY})
-	switch err {
-	case nil:
+	switch {
+	case err == nil:
 		defer fd.DecRef(ctx)
 
 		err := fd.IterDirents(ctx, vfs.IterDirentsCallbackFunc(func(dirent vfs.Dirent) error {
@@ -666,10 +667,10 @@ func (c *containerMounter) mountTmpVFS2(ctx context.Context, conf *config.Config
 			}
 			return nil
 		}))
-		switch err {
-		case nil:
+		switch {
+		case err == nil:
 			log.Infof(`Mounting internal tmpfs on top of empty "/tmp"`)
-		case syserror.ENOTEMPTY:
+		case linuxerr.Equals(linuxerr.ENOTEMPTY, err):
 			// If more than "." and ".." is found, skip internal tmpfs to prevent
 			// hiding existing files.
 			log.Infof(`Skipping internal tmpfs mount for "/tmp" because it's not empty`)
@@ -679,7 +680,7 @@ func (c *containerMounter) mountTmpVFS2(ctx context.Context, conf *config.Config
 		}
 		fallthrough
 
-	case syserror.ENOENT:
+	case linuxerr.Equals(linuxerr.ENOENT, err):
 		// No '/tmp' found (or fallthrough from above). It's safe to mount internal
 		// tmpfs.
 		tmpMount := specs.Mount{
@@ -692,7 +693,7 @@ func (c *containerMounter) mountTmpVFS2(ctx context.Context, conf *config.Config
 		_, err := c.mountSubmountVFS2(ctx, conf, mns, creds, &mountAndFD{mount: &tmpMount})
 		return err
 
-	case syserror.ENOTDIR:
+	case linuxerr.Equals(linuxerr.ENOTDIR, err):
 		// Not a dir?! Let it be.
 		return nil