helpers_test.go RawHistoryFolder

1//go:build integration
2
3package integration
4
5import (
6	"fmt"
7	"os"
8	"strings"
9	"syscall"
10	"time"
11	"unsafe"
12)
13
14type pollFd struct {
15	fd      int32
16	events  int16
17	revents int16
18}
19
20const pollIn = 0x1
21
22// pollPFD and pollTS are package-level because syscall.Syscall6 forces
23// pointer arguments passed through uintptr(unsafe.Pointer(&x)) to the heap.
24// Only the test goroutine (locked to its thread) uses them.
25var (
26	pollPFD pollFd
27	pollTS  syscall.Timespec
28)
29
30// waitReadable waits up to timeout for fd to become readable (or for a
31// signal). It does not allocate, so it can sit inside testing.AllocsPerRun.
32func waitReadable(fd int, timeout time.Duration) {
33	pollPFD = pollFd{fd: int32(fd), events: pollIn}
34	pollTS = syscall.Timespec{Sec: int64(timeout / time.Second), Nsec: int64(timeout % time.Second)}
35	_, _, _ = syscall.Syscall6(syscall.SYS_PPOLL, uintptr(unsafe.Pointer(&pollPFD)), 1, uintptr(unsafe.Pointer(&pollTS)), 0, 0, 0)
36}
37
38// isMapped reports whether the address of p lies inside a mapping listed in
39// /proc/self/maps.
40func isMapped(p *byte) bool {
41	addr := uint64(uintptr(unsafe.Pointer(p)))
42	b, err := os.ReadFile("/proc/self/maps")
43	if err != nil {
44		return true
45	}
46	for _, line := range strings.Split(string(b), "\n") {
47		var lo, hi uint64
48		if _, err := fmt.Sscanf(line, "%x-%x", &lo, &hi); err == nil && addr >= lo && addr < hi {
49			return true
50		}
51	}
52	return false
53}