container/init: measure init behaviour

This used to be entirely done via integration tests, with almost no hope of error injection and coverage profile. These tests significantly increase confidence of future work in this area.

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/init.go

@@ -127,7 +127,7 @@ func initEntrypoint(k syscallDispatcher, prepareLogger func(prefix string), setV
 
 	// write uid/gid map here so parent does not need to set dumpable
 	if err := k.setDumpable(SUID_DUMP_USER); err != nil {
-		k.fatalf("cannot set SUID_DUMP_USER: %s", err)
+		k.fatalf("cannot set SUID_DUMP_USER: %v", err)
 	}
 	if err := k.writeFile(FHSProc+"self/uid_map",
 		append([]byte{}, strconv.Itoa(params.Uid)+" "+strconv.Itoa(params.HostUid)+" 1\n"...),
@@ -145,7 +145,7 @@ func initEntrypoint(k syscallDispatcher, prepareLogger func(prefix string), setV
 		k.fatalf("%v", err)
 	}
 	if err := k.setDumpable(SUID_DUMP_DISABLE); err != nil {
-		k.fatalf("cannot set SUID_DUMP_DISABLE: %s", err)
+		k.fatalf("cannot set SUID_DUMP_DISABLE: %v", err)
 	}
 
 	oldmask := k.umask(0)
@@ -178,7 +178,6 @@ func initEntrypoint(k syscallDispatcher, prepareLogger func(prefix string), setV
 				fmt.Sprintf("cannot prepare op at index %d:", i))
 			k.beforeExit()
 			k.exit(1)
-			return
 		}
 	}
 
@@ -219,7 +218,6 @@ func initEntrypoint(k syscallDispatcher, prepareLogger func(prefix string), setV
 				fmt.Sprintf("cannot apply op at index %d:", i))
 			k.beforeExit()
 			k.exit(1)
-			return
 		}
 	}
 
@@ -250,7 +248,7 @@ func initEntrypoint(k syscallDispatcher, prepareLogger func(prefix string), setV
 			k.fatalf("cannot re-enter intermediate root: %v", err)
 		}
 		if err := k.unmount(".", MNT_DETACH); err != nil {
-			k.fatalf("cannot unmount intemediate root: %v", err)
+			k.fatalf("cannot unmount intermediate root: %v", err)
 		}
 		if err := k.chdir(FHSRoot); err != nil {
 			k.fatalf("cannot enter root: %v", err)
@@ -389,7 +387,6 @@ func initEntrypoint(k syscallDispatcher, prepareLogger func(prefix string), setV
 			}
 			k.beforeExit()
 			k.exit(0)
-			return
 
 		case w := <-info:
 			if w.wpid == cmd.Process.Pid {
@@ -416,13 +413,11 @@ func initEntrypoint(k syscallDispatcher, prepareLogger func(prefix string), setV
 		case <-done:
 			k.beforeExit()
 			k.exit(r)
-			return
 
 		case <-timeout:
 			k.printf("timeout exceeded waiting for lingering processes")
 			k.beforeExit()
 			k.exit(r)
-			return
 		}
 	}
 }