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metrics: use SYS_OPENAT

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New systems like arm64 don't even have SYS_OPEN.
This commit is contained in:
Brad Fitzpatrick 2021-09-02 15:28:19 -07:00
parent 159d88aae7
commit d1cb7a2639
2 changed files with 7 additions and 4 deletions
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8
metrics/fds_linux.go
View File

@ -9,6 +9,8 @@ import (
"log"
"syscall"
"unsafe"
"golang.org/x/sys/unix"
)
func currentFDs() int {
@ -81,10 +83,10 @@ func parseDirEnt(dirent *syscall.Dirent, buf []byte) (consumed int, name []byte)
var procSelfFDName = []byte("/proc/self/fd\x00")
func openProcSelfFD() (fd int, err error) {
var dirfd int = unix.AT_FDCWD
for {
r0, _, e1 := syscall.Syscall(syscall.SYS_OPEN,
uintptr(unsafe.Pointer(&procSelfFDName[0])),
0, 0)
r0, _, e1 := syscall.Syscall(unix.SYS_OPENAT, uintptr(dirfd),
uintptr(unsafe.Pointer(&procSelfFDName[0])), 0)
if e1 == 0 {
return int(r0), nil
}

3
metrics/metrics_test.go
View File

@ -34,10 +34,11 @@ func TestCurrentFileDescriptors(t *testing.T) {
t.Fatal(err)
}
defer f.Close()
t.Logf("fds for #%v = %v", i, CurrentFDs())
}
n2 := CurrentFDs()
if n2 != n+extra {
if n2 < n+extra {
t.Errorf("fds changed from %v => %v, want to %v", n, n2, n+extra)
}
}