Display list of precompiled seccomp-bpf programs in debug logs.

See [this comment](https://github.com/freedomofpress/dangerzone/pull/590#issuecomment-2149642086) for context.

PiperOrigin-RevId: 643463161

pkg/seccomp/precompiledseccomp/precompiled_lib.tmpl.go

@@ -17,6 +17,8 @@
 package precompiled
 
 import (
+	"sort"
+
 	"gvisor.dev/gvisor/pkg/seccomp/precompiledseccomp"
 	"gvisor.dev/gvisor/pkg/sync"
 )
@@ -39,6 +41,17 @@ func GetPrecompiled(programName string) (precompiledseccomp.Program, bool) {
 	return program, ok
 }
 
+// ListPrecompiled returns a list of all registered program names.
+func ListPrecompiled() []string {
+	registerPrecompiledProgramsOnce.Do(registerPrograms)
+	programNames := make([]string, 0, len(precompiledPrograms))
+	for name := range precompiledPrograms {
+		programNames = append(programNames, name)
+	}
+	sort.Strings(programNames)
+	return programNames
+}
+
 // registerPrograms registers available programs inside `precompiledPrograms`.
 func registerPrograms() {
 	programs := make(map[string]precompiledseccomp.Program)

runsc/boot/filter/filter.go

@@ -56,6 +56,13 @@ func Install(opt Options) error {
 		seccompOpts.DefaultAction = linux.SECCOMP_RET_TRAP
 	} else {
 		log.Infof("No precompiled program found for config options %v, building seccomp program from scratch. This may slow down container startup.", key)
+		if log.IsLogging(log.Debug) {
+			precompiledKeys := ListPrecompiled()
+			log.Debugf("Precompiled seccomp-bpf program configuration option variants (%d):", len(precompiledKeys))
+			for k := range precompiledKeys {
+				log.Debugf("  %v", k)
+			}
+		}
 	}
 	rules, denyRules := config.Rules(opt)
 	return seccomp.Install(rules, denyRules, seccompOpts)