From f413e4b11794cd71cc3b2b64c8f6861f5394a3f1 Mon Sep 17 00:00:00 2001
From: Fabricio Voznika <fvoznika@google.com>
Date: Thu, 11 Oct 2018 11:55:45 -0700
Subject: Add bare bones unsupported syscall logging

This change introduces a new flags to create/run called
--user-log. Logs to this files are visible to users and
are meant to help debugging problems with their images
and containers.

For now only unsupported syscalls are sent to this log,
and only minimum support was added. We can build more
infrastructure around it as needed.

PiperOrigin-RevId: 216735977
Change-Id: I54427ca194604991c407d49943ab3680470de2d0
---
 runsc/container/test_app.go | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

(limited to 'runsc/container/test_app.go')

diff --git a/runsc/container/test_app.go b/runsc/container/test_app.go
index f69cfdf83..9e4b5326d 100644
--- a/runsc/container/test_app.go
+++ b/runsc/container/test_app.go
@@ -24,6 +24,7 @@ import (
 	"os"
 	"os/exec"
 	"strconv"
+	sys "syscall"
 	"time"
 
 	"flag"
@@ -38,6 +39,7 @@ func main() {
 	subcommands.Register(new(taskTree), "")
 	subcommands.Register(new(forkBomb), "")
 	subcommands.Register(new(reaper), "")
+	subcommands.Register(new(syscall), "")
 
 	flag.Parse()
 
@@ -241,3 +243,37 @@ func (c *reaper) Execute(ctx context.Context, f *flag.FlagSet, args ...interface
 	defer stop()
 	select {}
 }
+
+type syscall struct {
+	sysno uint64
+}
+
+// Name implements subcommands.Command.
+func (*syscall) Name() string {
+	return "syscall"
+}
+
+// Synopsis implements subcommands.Command.
+func (*syscall) Synopsis() string {
+	return "syscall makes a syscall"
+}
+
+// Usage implements subcommands.Command.
+func (*syscall) Usage() string {
+	return "syscall <flags>"
+}
+
+// SetFlags implements subcommands.Command.
+func (s *syscall) SetFlags(f *flag.FlagSet) {
+	f.Uint64Var(&s.sysno, "syscall", 0, "syscall to call")
+}
+
+// Execute implements subcommands.Command.
+func (s *syscall) Execute(ctx context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus {
+	if _, _, errno := sys.Syscall(uintptr(s.sysno), 0, 0, 0); errno != 0 {
+		fmt.Printf("syscall(%d, 0, 0...) failed: %v\n", s.sysno, errno)
+	} else {
+		fmt.Printf("syscall(%d, 0, 0...) success\n", s.sysno)
+	}
+	return subcommands.ExitSuccess
+}
-- 
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