[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, 34 insertions, 31 deletions

diff --git a/pkg/sentry/fsimpl/verity/BUILD b/pkg/sentry/fsimpl/verity/BUILD
index d473a922d..1d855234c 100644
--- a/pkg/sentry/fsimpl/verity/BUILD
+++ b/pkg/sentry/fsimpl/verity/BUILD
@@ -13,6 +13,7 @@ go_library(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/errors/linuxerr",
         "//pkg/fspath",
         "//pkg/hostarch",
         "//pkg/marshal/primitive",
@@ -41,6 +42,7 @@ go_test(
     deps = [
         "//pkg/abi/linux",
         "//pkg/context",
+        "//pkg/errors/linuxerr",
         "//pkg/fspath",
         "//pkg/sentry/arch",
         "//pkg/sentry/fsimpl/testutil",
@@ -48,7 +50,6 @@ go_test(
         "//pkg/sentry/kernel",
         "//pkg/sentry/kernel/auth",
         "//pkg/sentry/vfs",
-        "//pkg/syserror",
         "//pkg/usermem",
     ],
 )
diff --git a/pkg/sentry/fsimpl/verity/filesystem.go b/pkg/sentry/fsimpl/verity/filesystem.go
index 3582d14c9..e84452421 100644
--- a/pkg/sentry/fsimpl/verity/filesystem.go
+++ b/pkg/sentry/fsimpl/verity/filesystem.go
@@ -25,6 +25,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/errors/linuxerr"
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/merkletree"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
@@ -195,7 +196,7 @@ func (fs *filesystem) verifyChildLocked(ctx context.Context, parent *dentry, chi
 	// The Merkle tree file for the child should have been created and
 	// contains the expected xattrs. If the file or the xattr does not
 	// exist, it indicates unexpected modifications to the file system.
-	if err == syserror.ENOENT || err == syserror.ENODATA {
+	if linuxerr.Equals(linuxerr.ENOENT, err) || linuxerr.Equals(linuxerr.ENODATA, err) {
 		return nil, fs.alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s for %s: %v", merkleOffsetInParentXattr, childPath, err))
 	}
 	if err != nil {
@@ -218,7 +219,7 @@ func (fs *filesystem) verifyChildLocked(ctx context.Context, parent *dentry, chi
 
 	// The parent Merkle tree file should have been created. If it's
 	// missing, it indicates an unexpected modification to the file system.
-	if err == syserror.ENOENT {
+	if linuxerr.Equals(linuxerr.ENOENT, err) {
 		return nil, fs.alertIntegrityViolation(fmt.Sprintf("Failed to open parent Merkle file for %s: %v", childPath, err))
 	}
 	if err != nil {
@@ -238,7 +239,7 @@ func (fs *filesystem) verifyChildLocked(ctx context.Context, parent *dentry, chi
 	// The Merkle tree file for the child should have been created and
 	// contains the expected xattrs. If the file or the xattr does not
 	// exist, it indicates unexpected modifications to the file system.
-	if err == syserror.ENOENT || err == syserror.ENODATA {
+	if linuxerr.Equals(linuxerr.ENOENT, err) || linuxerr.Equals(linuxerr.ENODATA, err) {
 		return nil, fs.alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s for %s: %v", merkleSizeXattr, childPath, err))
 	}
 	if err != nil {
@@ -261,7 +262,7 @@ func (fs *filesystem) verifyChildLocked(ctx context.Context, parent *dentry, chi
 		Root:  parent.lowerVD,
 		Start: parent.lowerVD,
 	}, &vfs.StatOptions{})
-	if err == syserror.ENOENT {
+	if linuxerr.Equals(linuxerr.ENOENT, err) {
 		return nil, fs.alertIntegrityViolation(fmt.Sprintf("Failed to get parent stat for %s: %v", childPath, err))
 	}
 	if err != nil {
@@ -327,7 +328,7 @@ func (fs *filesystem) verifyStatAndChildrenLocked(ctx context.Context, d *dentry
 	}, &vfs.OpenOptions{
 		Flags: linux.O_RDONLY,
 	})
-	if err == syserror.ENOENT {
+	if linuxerr.Equals(linuxerr.ENOENT, err) {
 		return fs.alertIntegrityViolation(fmt.Sprintf("Failed to open merkle file for %s: %v", childPath, err))
 	}
 	if err != nil {
@@ -341,7 +342,7 @@ func (fs *filesystem) verifyStatAndChildrenLocked(ctx context.Context, d *dentry
 		Size: sizeOfStringInt32,
 	})
 
-	if err == syserror.ENODATA {
+	if linuxerr.Equals(linuxerr.ENODATA, err) {
 		return fs.alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s for merkle file of %s: %v", merkleSizeXattr, childPath, err))
 	}
 	if err != nil {
@@ -359,7 +360,7 @@ func (fs *filesystem) verifyStatAndChildrenLocked(ctx context.Context, d *dentry
 			Size: sizeOfStringInt32,
 		})
 
-		if err == syserror.ENODATA {
+		if linuxerr.Equals(linuxerr.ENODATA, err) {
 			return fs.alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s for merkle file of %s: %v", childrenOffsetXattr, childPath, err))
 		}
 		if err != nil {
@@ -375,7 +376,7 @@ func (fs *filesystem) verifyStatAndChildrenLocked(ctx context.Context, d *dentry
 			Size: sizeOfStringInt32,
 		})
 
-		if err == syserror.ENODATA {
+		if linuxerr.Equals(linuxerr.ENODATA, err) {
 			return fs.alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s for merkle file of %s: %v", childrenSizeXattr, childPath, err))
 		}
 		if err != nil {
@@ -465,7 +466,7 @@ func (fs *filesystem) getChildLocked(ctx context.Context, parent *dentry, name s
 			}
 
 			childVD, err := parent.getLowerAt(ctx, vfsObj, name)
-			if err == syserror.ENOENT {
+			if linuxerr.Equals(linuxerr.ENOENT, err) {
 				// The file was previously accessed. If the
 				// file does not exist now, it indicates an
 				// unexpected modification to the file system.
@@ -480,7 +481,7 @@ func (fs *filesystem) getChildLocked(ctx context.Context, parent *dentry, name s
 			// The Merkle tree file was previous accessed. If it
 			// does not exist now, it indicates an unexpected
 			// modification to the file system.
-			if err == syserror.ENOENT {
+			if linuxerr.Equals(linuxerr.ENOENT, err) {
 				return nil, fs.alertIntegrityViolation(fmt.Sprintf("Expected Merkle file for target %s but none found", path))
 			}
 			if err != nil {
@@ -551,7 +552,7 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry,
 	}
 
 	childVD, err := parent.getLowerAt(ctx, vfsObj, name)
-	if parent.verityEnabled() && err == syserror.ENOENT {
+	if parent.verityEnabled() && linuxerr.Equals(linuxerr.ENOENT, err) {
 		return nil, fs.alertIntegrityViolation(fmt.Sprintf("file %s expected but not found", parentPath+"/"+name))
 	}
 	if err != nil {
@@ -564,7 +565,7 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry,
 
 	childMerkleVD, err := parent.getLowerAt(ctx, vfsObj, merklePrefix+name)
 	if err != nil {
-		if err == syserror.ENOENT {
+		if linuxerr.Equals(linuxerr.ENOENT, err) {
 			if parent.verityEnabled() {
 				return nil, fs.alertIntegrityViolation(fmt.Sprintf("Merkle file for %s expected but not found", parentPath+"/"+name))
 			}
@@ -854,7 +855,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
 	// The file should exist, as we succeeded in finding its dentry. If it's
 	// missing, it indicates an unexpected modification to the file system.
 	if err != nil {
-		if err == syserror.ENOENT {
+		if linuxerr.Equals(linuxerr.ENOENT, err) {
 			return nil, d.fs.alertIntegrityViolation(fmt.Sprintf("File %s expected but not found", path))
 		}
 		return nil, err
@@ -877,7 +878,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
 	// dentry. If it's missing, it indicates an unexpected modification to
 	// the file system.
 	if err != nil {
-		if err == syserror.ENOENT {
+		if linuxerr.Equals(linuxerr.ENOENT, err) {
 			return nil, d.fs.alertIntegrityViolation(fmt.Sprintf("Merkle file for %s expected but not found", path))
 		}
 		return nil, err
@@ -902,7 +903,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
 			Flags: linux.O_WRONLY | linux.O_APPEND,
 		})
 		if err != nil {
-			if err == syserror.ENOENT {
+			if linuxerr.Equals(linuxerr.ENOENT, err) {
 				return nil, d.fs.alertIntegrityViolation(fmt.Sprintf("Merkle file for %s expected but not found", path))
 			}
 			return nil, err
@@ -919,7 +920,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
 				Flags: linux.O_WRONLY | linux.O_APPEND,
 			})
 			if err != nil {
-				if err == syserror.ENOENT {
+				if linuxerr.Equals(linuxerr.ENOENT, err) {
 					parentPath, _ := d.fs.vfsfs.VirtualFilesystem().PathnameWithDeleted(ctx, d.fs.rootDentry.lowerVD, d.parent.lowerVD)
 					return nil, d.fs.alertIntegrityViolation(fmt.Sprintf("Merkle file for %s expected but not found", parentPath))
 				}
diff --git a/pkg/sentry/fsimpl/verity/verity.go b/pkg/sentry/fsimpl/verity/verity.go
index 969003613..c5f59d851 100644
--- a/pkg/sentry/fsimpl/verity/verity.go
+++ b/pkg/sentry/fsimpl/verity/verity.go
@@ -45,6 +45,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/errors/linuxerr"
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/marshal/primitive"
@@ -358,7 +359,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 
 	// If runtime enable is allowed, the root merkle tree may be absent. We
 	// should create the tree file.
-	if err == syserror.ENOENT && fs.allowRuntimeEnable {
+	if linuxerr.Equals(linuxerr.ENOENT, err) && fs.allowRuntimeEnable {
 		lowerMerkleFD, err := vfsObj.OpenAt(ctx, fs.creds, &vfs.PathOperation{
 			Root:  lowerVD,
 			Start: lowerVD,
@@ -451,7 +452,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 			Name: childrenOffsetXattr,
 			Size: sizeOfStringInt32,
 		})
-		if err == syserror.ENOENT || err == syserror.ENODATA {
+		if linuxerr.Equals(linuxerr.ENOENT, err) || linuxerr.Equals(linuxerr.ENODATA, err) {
 			return nil, nil, fs.alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s: %v", childrenOffsetXattr, err))
 		}
 		if err != nil {
@@ -470,7 +471,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 			Name: childrenSizeXattr,
 			Size: sizeOfStringInt32,
 		})
-		if err == syserror.ENOENT || err == syserror.ENODATA {
+		if linuxerr.Equals(linuxerr.ENOENT, err) || linuxerr.Equals(linuxerr.ENODATA, err) {
 			return nil, nil, fs.alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s: %v", childrenSizeXattr, err))
 		}
 		if err != nil {
@@ -487,7 +488,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 		}, &vfs.OpenOptions{
 			Flags: linux.O_RDONLY,
 		})
-		if err == syserror.ENOENT {
+		if linuxerr.Equals(linuxerr.ENOENT, err) {
 			return nil, nil, fs.alertIntegrityViolation(fmt.Sprintf("Failed to open root Merkle file: %v", err))
 		}
 		if err != nil {
@@ -1227,7 +1228,7 @@ func (fd *fileDescription) PRead(ctx context.Context, dst usermem.IOSequence, of
 	// The Merkle tree file for the child should have been created and
 	// contains the expected xattrs. If the xattr does not exist, it
 	// indicates unexpected modifications to the file system.
-	if err == syserror.ENODATA {
+	if linuxerr.Equals(linuxerr.ENODATA, err) {
 		return 0, fd.d.fs.alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s: %v", merkleSizeXattr, err))
 	}
 	if err != nil {
@@ -1349,7 +1350,7 @@ func (fd *fileDescription) Translate(ctx context.Context, required, optional mem
 	// The Merkle tree file for the child should have been created and
 	// contains the expected xattrs. If the xattr does not exist, it
 	// indicates unexpected modifications to the file system.
-	if err == syserror.ENODATA {
+	if linuxerr.Equals(linuxerr.ENODATA, err) {
 		return nil, fd.d.fs.alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s: %v", merkleSizeXattr, err))
 	}
 	if err != nil {
diff --git a/pkg/sentry/fsimpl/verity/verity_test.go b/pkg/sentry/fsimpl/verity/verity_test.go
index 5c78a0019..65465b814 100644
--- a/pkg/sentry/fsimpl/verity/verity_test.go
+++ b/pkg/sentry/fsimpl/verity/verity_test.go
@@ -24,6 +24,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/errors/linuxerr"
 	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/testutil"
@@ -31,7 +32,6 @@ 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/pkg/usermem"
 )
 
@@ -476,7 +476,7 @@ func TestOpenNonexistentFile(t *testing.T) {
 
 	// Ensure open an unexpected file in the parent directory fails with
 	// ENOENT rather than verification failure.
-	if _, err = openVerityAt(ctx, vfsObj, root, filename+"abc", linux.O_RDONLY, linux.ModeRegular); err != syserror.ENOENT {
+	if _, err = openVerityAt(ctx, vfsObj, root, filename+"abc", linux.O_RDONLY, linux.ModeRegular); !linuxerr.Equals(linuxerr.ENOENT, err) {
 		t.Errorf("OpenAt unexpected error: %v", err)
 	}
 }
@@ -767,7 +767,7 @@ func TestOpenDeletedFileFails(t *testing.T) {
 			}
 
 			// Ensure reopening the verity enabled file fails.
-			if _, err = openVerityAt(ctx, vfsObj, root, filename, linux.O_RDONLY, linux.ModeRegular); err != syserror.EIO {
+			if _, err = openVerityAt(ctx, vfsObj, root, filename, linux.O_RDONLY, linux.ModeRegular); !linuxerr.Equals(linuxerr.EIO, err) {
 				t.Errorf("got OpenAt error: %v, expected EIO", err)
 			}
 		})
@@ -829,7 +829,7 @@ func TestOpenRenamedFileFails(t *testing.T) {
 			}
 
 			// Ensure reopening the verity enabled file fails.
-			if _, err = openVerityAt(ctx, vfsObj, root, filename, linux.O_RDONLY, linux.ModeRegular); err != syserror.EIO {
+			if _, err = openVerityAt(ctx, vfsObj, root, filename, linux.O_RDONLY, linux.ModeRegular); !linuxerr.Equals(linuxerr.EIO, err) {
 				t.Errorf("got OpenAt error: %v, expected EIO", err)
 			}
 		})
@@ -1063,14 +1063,14 @@ func TestDeletedSymlinkFileReadFails(t *testing.T) {
 				Root:  root,
 				Start: root,
 				Path:  fspath.Parse(symlink),
-			}); err != syserror.EIO {
+			}); !linuxerr.Equals(linuxerr.EIO, err) {
 				t.Fatalf("ReadlinkAt succeeded with modified symlink: %v", err)
 			}
 
 			if tc.testWalk {
 				fileInSymlinkDirectory := symlink + "/verity-test-file"
 				// Ensure opening the verity enabled file in the symlink directory fails.
-				if _, err := openVerityAt(ctx, vfsObj, root, fileInSymlinkDirectory, linux.O_RDONLY, linux.ModeRegular); err != syserror.EIO {
+				if _, err := openVerityAt(ctx, vfsObj, root, fileInSymlinkDirectory, linux.O_RDONLY, linux.ModeRegular); !linuxerr.Equals(linuxerr.EIO, err) {
 					t.Errorf("Open succeeded with modified symlink: %v", err)
 				}
 			}
@@ -1195,14 +1195,14 @@ func TestModifiedSymlinkFileReadFails(t *testing.T) {
 				Root:  root,
 				Start: root,
 				Path:  fspath.Parse(symlink),
-			}); err != syserror.EIO {
+			}); !linuxerr.Equals(linuxerr.EIO, err) {
 				t.Fatalf("ReadlinkAt succeeded with modified symlink: %v", err)
 			}
 
 			if tc.testWalk {
 				fileInSymlinkDirectory := symlink + "/verity-test-file"
 				// Ensure opening the verity enabled file in the symlink directory fails.
-				if _, err := openVerityAt(ctx, vfsObj, root, fileInSymlinkDirectory, linux.O_RDONLY, linux.ModeRegular); err != syserror.EIO {
+				if _, err := openVerityAt(ctx, vfsObj, root, fileInSymlinkDirectory, linux.O_RDONLY, linux.ModeRegular); !linuxerr.Equals(linuxerr.EIO, err) {
 					t.Errorf("Open succeeded with modified symlink: %v", err)
 				}
 			}