add tests for prlimit

Signed-off-by: lifubang <[email protected]>

src/syscall/syscall_linux_test.go

@@ -17,6 +17,7 @@ import (
  "strconv"
  "strings"
  "sync"
+ "sync/atomic"
  "syscall"
  "testing"
  "unsafe"
@@ -654,3 +655,56 @@ func TestAllThreadsSyscallBlockedSyscall(t *testing.T) {
  wr.Close()
  wg.Wait()
 }
+
+//go:linkname syscall_prlimit syscall.prlimit
+func syscall_prlimit(pid, resource int, newlimit, old *syscall.Rlimit) error
+
+//go:linkname syscall_origRlimitNofile syscall.origRlimitNofile
+var syscall_origRlimitNofile atomic.Pointer[syscall.Rlimit]
+
+func TestPrlimitSelf(t *testing.T) {
+ rlimOrig := syscall_origRlimitNofile.Load()
+
+ // Get the current nofile limit
+ var lim syscall.Rlimit
+ if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim); err != nil {
+ t.Fatalf("Failed to get the current nofile limit: %v", err)
+ }
+ // Set current process's nofile limit through prlimit
+ if err := syscall_prlimit(0, syscall.RLIMIT_NOFILE, &lim, nil); err != nil {
+ t.Fatalf("Prlimit self failed: %v", err)
+ }
+
+ rlimLater := syscall_origRlimitNofile.Load()
+ if rlimOrig != nil && rlimLater == rlimOrig {
+ t.Fatal("The nofile limit cache should be cleared after setting our own nofile limit through prlimit!")
+ }
+}
+
+func TestPrlimitOtherProcess(t *testing.T) {
+ rlimOrig := syscall_origRlimitNofile.Load()
+
+ // Get the current nofile limit
+ var lim syscall.Rlimit
+ if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim); err != nil {
+ t.Fatalf("Failed to get the current nofile limit: %v", err)
+ }
+
+ // Start a child process firstly,
+ // so we can use Prlimit to set it's nofile limit.
+ cmd := exec.Command("sleep", "infinity")
+ cmd.Start()
+
+ // Set child process's nofile rlimit through prlimit
+ if err := syscall_prlimit(cmd.Process.Pid, syscall.RLIMIT_NOFILE, &lim, nil); err != nil {
+ t.Fatalf("Prlimit(%d) failed: %v", cmd.Process.Pid, err)
+ }
+
+ cmd.Process.Kill()
+ cmd.Process.Wait()
+
+ rlimLater := syscall_origRlimitNofile.Load()
+ if rlimOrig != nil && rlimLater != rlimOrig {
+ t.Fatal("The nofile limit cache should not be cleared after setting other process's nofile limit through prlimit!")
+ }
+}