Simplify FD handling for container start/exec

VFS1 and VFS2 host FDs have different dupping behavior,
making error prone to code for both. Change the contract
so that FDs are released as they are used, so the caller
can simple defer a block that closes all remaining files.
This also addresses handling of partial failures.

With this fix, more VFS2 tests can be enabled.

Updates #1487

PiperOrigin-RevId: 330112266

1 files changed, 9 insertions, 19 deletions

diff --git a/pkg/sentry/control/proc.go b/pkg/sentry/control/proc.go
index dfa936563..668f47802 100644
--- a/pkg/sentry/control/proc.go
+++ b/pkg/sentry/control/proc.go
@@ -23,8 +23,8 @@ import (
 	"text/tabwriter"
 	"time"
 
-	"golang.org/x/sys/unix"
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/sentry/fdimport"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	"gvisor.dev/gvisor/pkg/sentry/fs/host"
@@ -203,27 +203,17 @@ func (proc *Proc) execAsync(args *ExecArgs) (*kernel.ThreadGroup, kernel.ThreadI
 	}
 	initArgs.Filename = resolved
 
-	fds := make([]int, len(args.FilePayload.Files))
-	for i, file := range args.FilePayload.Files {
-		if kernel.VFS2Enabled {
-			// Need to dup to remove ownership from os.File.
-			dup, err := unix.Dup(int(file.Fd()))
-			if err != nil {
-				return nil, 0, nil, nil, fmt.Errorf("duplicating payload files: %w", err)
-			}
-			fds[i] = dup
-		} else {
-			// VFS1 dups the file on import.
-			fds[i] = int(file.Fd())
-		}
+	fds, err := fd.NewFromFiles(args.Files)
+	if err != nil {
+		return nil, 0, nil, nil, fmt.Errorf("duplicating payload files: %w", err)
 	}
+	defer func() {
+		for _, fd := range fds {
+			_ = fd.Close()
+		}
+	}()
 	ttyFile, ttyFileVFS2, err := fdimport.Import(ctx, fdTable, args.StdioIsPty, fds)
 	if err != nil {
-		if kernel.VFS2Enabled {
-			for _, fd := range fds {
-				unix.Close(fd)
-			}
-		}
 		return nil, 0, nil, nil, err
 	}