Fix runsc syscall documentation generation.

We can register any number of tables with any number of architectures, and
need not limit the definitions to the architecture in question. This allows
runsc to generate documentation for all architectures simultaneously.

Similarly, this simplifies the VFSv2 patching process.

PiperOrigin-RevId: 310224827

1 files changed, 16 insertions, 7 deletions

diff --git a/runsc/cmd/syscalls.go b/runsc/cmd/syscalls.go
index 7072547be..a37d66139 100644
--- a/runsc/cmd/syscalls.go
+++ b/runsc/cmd/syscalls.go
@@ -32,9 +32,10 @@ import (
 
 // Syscalls implements subcommands.Command for the "syscalls" command.
 type Syscalls struct {
-	output string
-	os     string
-	arch   string
+	format   string
+	os       string
+	arch     string
+	filename string
 }
 
 // CompatibilityInfo is a map of system and architecture to compatibility doc.
@@ -95,16 +96,17 @@ func (*Syscalls) Usage() string {
 
 // SetFlags implements subcommands.Command.SetFlags.
 func (s *Syscalls) SetFlags(f *flag.FlagSet) {
-	f.StringVar(&s.output, "o", "table", "Output format (table, csv, json).")
+	f.StringVar(&s.format, "format", "table", "Output format (table, csv, json).")
 	f.StringVar(&s.os, "os", osAll, "The OS (e.g. linux)")
 	f.StringVar(&s.arch, "arch", archAll, "The CPU architecture (e.g. amd64).")
+	f.StringVar(&s.filename, "filename", "", "Output filename (otherwise stdout).")
 }
 
 // Execute implements subcommands.Command.Execute.
 func (s *Syscalls) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
-	out, ok := outputMap[s.output]
+	out, ok := outputMap[s.format]
 	if !ok {
-		Fatalf("Unsupported output format %q", s.output)
+		Fatalf("Unsupported output format %q", s.format)
 	}
 
 	// Build map of all supported architectures.
@@ -124,7 +126,14 @@ func (s *Syscalls) Execute(_ context.Context, f *flag.FlagSet, args ...interface
 		Fatalf("%v", err)
 	}
 
-	if err := out(os.Stdout, info); err != nil {
+	w := os.Stdout // Default.
+	if s.filename != "" {
+		w, err = os.OpenFile(s.filename, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
+		if err != nil {
+			Fatalf("Error opening %q: %v", s.filename, err)
+		}
+	}
+	if err := out(w, info); err != nil {
 		Fatalf("Error writing output: %v", err)
 	}