test/runtime: set the NOFILE soft rlimit to 32K

The python:test_subprocess enumerates all possible file descriptors and fails
by timeout if the limit is too high.

There is a know thing about docker that it sets this limit to 1M by default,
but on native linux, this limit will be between 1K to 32K.

PiperOrigin-RevId: 338197239

2 files changed, 28 insertions, 1 deletions

diff --git a/test/runtimes/exclude/python3.7.3.csv b/test/runtimes/exclude/python3.7.3.csv
index 8760f8951..911f22855 100644
--- a/test/runtimes/exclude/python3.7.3.csv
+++ b/test/runtimes/exclude/python3.7.3.csv
@@ -18,4 +18,3 @@ test_selectors,b/76116849,OSError not raised with epoll
 test_smtplib,b/162980434,unclosed sockets
 test_signal,,Flaky - signal: alarm clock
 test_socket,b/75983380,
-test_subprocess,b/162980831,
diff --git a/test/runtimes/proctor/main.go b/test/runtimes/proctor/main.go
index e5607ac92..81cb68381 100644
--- a/test/runtimes/proctor/main.go
+++ b/test/runtimes/proctor/main.go
@@ -22,6 +22,7 @@ import (
 	"log"
 	"os"
 	"strings"
+	"syscall"
 
 	"gvisor.dev/gvisor/test/runtimes/proctor/lib"
 )
@@ -33,6 +34,29 @@ var (
 	pause     = flag.Bool("pause", false, "cause container to pause indefinitely, reaping any zombie children")
 )
 
+// setNumFilesLimit changes the NOFILE soft rlimit if it is too high.
+func setNumFilesLimit() error {
+	// In docker containers, the default value of the NOFILE limit is
+	// 1048576. A few runtime tests (e.g. python:test_subprocess)
+	// enumerates all possible file descriptors and these tests can fail by
+	// timeout if the NOFILE limit is too high. On gVisor, syscalls are
+	// slower so these tests will need even more time to pass.
+	const nofile = 32768
+	rLimit := syscall.Rlimit{}
+	err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rLimit)
+	if err != nil {
+		return fmt.Errorf("failed to get RLIMIT_NOFILE: %v", err)
+	}
+	if rLimit.Cur > nofile {
+		rLimit.Cur = nofile
+		err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rLimit)
+		if err != nil {
+			return fmt.Errorf("failed to set RLIMIT_NOFILE: %v", err)
+		}
+	}
+	return nil
+}
+
 func main() {
 	flag.Parse()
 
@@ -74,6 +98,10 @@ func main() {
 		tests = strings.Split(*testNames, ",")
 	}
 
+	if err := setNumFilesLimit(); err != nil {
+		log.Fatalf("%v", err)
+	}
+
 	// Run tests.
 	cmds := tr.TestCmds(tests)
 	for _, cmd := range cmds {