syscall: always use prlimit for getrlimit/setrlimit on Linux

Linux added the prlimit system call in version 2.6.36.
As our minimum Linux kernel version is now 3.2,
simplify the various getrlimit/setlrimit implementations
to just always use prlimit.

For #67001

Change-Id: I2512c21c947d0bc83f8f9077c143163fd8d83be3
Reviewed-on: https://go-review.googlesource.com/c/go/+/609178
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/syscall/syscall_linux.go b/src/syscall/syscall_linux.go
index 032936398b..1fe422d691 100644
--- a/src/syscall/syscall_linux.go
+++ b/src/syscall/syscall_linux.go
@@ -1288,6 +1288,17 @@ func Munmap(b []byte) (err error) {
 //sys	Mlockall(flags int) (err error)
 //sys	Munlockall() (err error)
 
+func Getrlimit(resource int, rlim *Rlimit) (err error) {
+	// prlimit1 is the same as prlimit when newlimit == nil
+	return prlimit1(0, resource, nil, rlim)
+}
+
+// setrlimit sets a resource limit.
+// The Setrlimit function is in rlimit.go, and calls this one.
+func setrlimit(resource int, rlim *Rlimit) (err error) {
+	return prlimit(0, resource, rlim, nil)
+}
+
 // prlimit changes a resource limit. We use a single definition so that
 // we can tell StartProcess to not restore the original NOFILE limit.
 //