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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build linux && cgo
// +build linux,cgo
package cgotest
import (
"fmt"
"os"
"runtime"
"sort"
"strings"
"syscall"
"testing"
)
// #include <stdio.h>
// #include <stdlib.h>
// #include <pthread.h>
// #include <unistd.h>
// #include <sys/types.h>
//
// pthread_t *t = NULL;
// pthread_mutex_t mu;
// int nts = 0;
// int all_done = 0;
//
// static void *aFn(void *vargp) {
// int done = 0;
// while (!done) {
// usleep(100);
// pthread_mutex_lock(&mu);
// done = all_done;
// pthread_mutex_unlock(&mu);
// }
// return NULL;
// }
//
// void trial(int argc) {
// int i;
// nts = argc;
// t = calloc(nts, sizeof(pthread_t));
// pthread_mutex_init(&mu, NULL);
// for (i = 0; i < nts; i++) {
// pthread_create(&t[i], NULL, aFn, NULL);
// }
// }
//
// void cleanup(void) {
// int i;
// pthread_mutex_lock(&mu);
// all_done = 1;
// pthread_mutex_unlock(&mu);
// for (i = 0; i < nts; i++) {
// pthread_join(t[i], NULL);
// }
// pthread_mutex_destroy(&mu);
// free(t);
// }
import "C"
// compareStatus is used to confirm the contents of the thread
// specific status files match expectations.
func compareStatus(filter, expect string) error {
expected := filter + expect
pid := syscall.Getpid()
fs, err := os.ReadDir(fmt.Sprintf("/proc/%d/task", pid))
if err != nil {
return fmt.Errorf("unable to find %d tasks: %v", pid, err)
}
expectedProc := fmt.Sprintf("Pid:\t%d", pid)
foundAThread := false
for _, f := range fs {
tf := fmt.Sprintf("/proc/%s/status", f.Name())
d, err := os.ReadFile(tf)
if err != nil {
// There are a surprising number of ways this
// can error out on linux. We've seen all of
// the following, so treat any error here as
// equivalent to the "process is gone":
// os.IsNotExist(err),
// "... : no such process",
// "... : bad file descriptor.
continue
}
lines := strings.Split(string(d), "\n")
for _, line := range lines {
// Different kernel vintages pad differently.
line = strings.TrimSpace(line)
if strings.HasPrefix(line, "Pid:\t") {
// On loaded systems, it is possible
// for a TID to be reused really
// quickly. As such, we need to
// validate that the thread status
// info we just read is a task of the
// same process PID as we are
// currently running, and not a
// recently terminated thread
// resurfaced in a different process.
if line != expectedProc {
break
}
// Fall through in the unlikely case
// that filter at some point is
// "Pid:\t".
}
if strings.HasPrefix(line, filter) {
if line == expected {
foundAThread = true
break
}
if filter == "Groups:" && strings.HasPrefix(line, "Groups:\t") {
// https://github.com/golang/go/issues/46145
// Containers don't reliably output this line in sorted order so manually sort and compare that.
a := strings.Split(line[8:], " ")
sort.Strings(a)
got := strings.Join(a, " ")
if got == expected[8:] {
foundAThread = true
break
}
}
return fmt.Errorf("%q got:%q want:%q (bad) [pid=%d file:'%s' %v]\n", tf, line, expected, pid, string(d), expectedProc)
}
}
}
if !foundAThread {
return fmt.Errorf("found no thread /proc/<TID>/status files for process %q", expectedProc)
}
return nil
}
// test1435 test 9 glibc implemented setuid/gid syscall functions are
// mapped. This test is a slightly more expansive test than that of
// src/syscall/syscall_linux_test.go:TestSetuidEtc() insofar as it
// launches concurrent threads from C code via CGo and validates that
// they are subject to the system calls being tested. For the actual
// Go functionality being tested here, the syscall_linux_test version
// is considered authoritative, but non-trivial improvements to that
// should be mirrored here.
func test1435(t *testing.T) {
if syscall.Getuid() != 0 {
t.Skip("skipping root only test")
}
if runtime.GOOS == "linux" {
if _, err := os.Stat("/etc/alpine-release"); err == nil {
t.Skip("skipping failing test on alpine - go.dev/issue/19938")
}
}
// Launch some threads in C.
const cts = 5
C.trial(cts)
defer C.cleanup()
vs := []struct {
call string
fn func() error
filter, expect string
}{
{call: "Setegid(1)", fn: func() error { return syscall.Setegid(1) }, filter: "Gid:", expect: "\t0\t1\t0\t1"},
{call: "Setegid(0)", fn: func() error { return syscall.Setegid(0) }, filter: "Gid:", expect: "\t0\t0\t0\t0"},
{call: "Seteuid(1)", fn: func() error { return syscall.Seteuid(1) }, filter: "Uid:", expect: "\t0\t1\t0\t1"},
{call: "Setuid(0)", fn: func() error { return syscall.Setuid(0) }, filter: "Uid:", expect: "\t0\t0\t0\t0"},
{call: "Setgid(1)", fn: func() error { return syscall.Setgid(1) }, filter: "Gid:", expect: "\t1\t1\t1\t1"},
{call: "Setgid(0)", fn: func() error { return syscall.Setgid(0) }, filter: "Gid:", expect: "\t0\t0\t0\t0"},
{call: "Setgroups([]int{0,1,2,3})", fn: func() error { return syscall.Setgroups([]int{0, 1, 2, 3}) }, filter: "Groups:", expect: "\t0 1 2 3"},
{call: "Setgroups(nil)", fn: func() error { return syscall.Setgroups(nil) }, filter: "Groups:", expect: ""},
{call: "Setgroups([]int{0})", fn: func() error { return syscall.Setgroups([]int{0}) }, filter: "Groups:", expect: "\t0"},
{call: "Setregid(101,0)", fn: func() error { return syscall.Setregid(101, 0) }, filter: "Gid:", expect: "\t101\t0\t0\t0"},
{call: "Setregid(0,102)", fn: func() error { return syscall.Setregid(0, 102) }, filter: "Gid:", expect: "\t0\t102\t102\t102"},
{call: "Setregid(0,0)", fn: func() error { return syscall.Setregid(0, 0) }, filter: "Gid:", expect: "\t0\t0\t0\t0"},
{call: "Setreuid(1,0)", fn: func() error { return syscall.Setreuid(1, 0) }, filter: "Uid:", expect: "\t1\t0\t0\t0"},
{call: "Setreuid(0,2)", fn: func() error { return syscall.Setreuid(0, 2) }, filter: "Uid:", expect: "\t0\t2\t2\t2"},
{call: "Setreuid(0,0)", fn: func() error { return syscall.Setreuid(0, 0) }, filter: "Uid:", expect: "\t0\t0\t0\t0"},
{call: "Setresgid(101,0,102)", fn: func() error { return syscall.Setresgid(101, 0, 102) }, filter: "Gid:", expect: "\t101\t0\t102\t0"},
{call: "Setresgid(0,102,101)", fn: func() error { return syscall.Setresgid(0, 102, 101) }, filter: "Gid:", expect: "\t0\t102\t101\t102"},
{call: "Setresgid(0,0,0)", fn: func() error { return syscall.Setresgid(0, 0, 0) }, filter: "Gid:", expect: "\t0\t0\t0\t0"},
{call: "Setresuid(1,0,2)", fn: func() error { return syscall.Setresuid(1, 0, 2) }, filter: "Uid:", expect: "\t1\t0\t2\t0"},
{call: "Setresuid(0,2,1)", fn: func() error { return syscall.Setresuid(0, 2, 1) }, filter: "Uid:", expect: "\t0\t2\t1\t2"},
{call: "Setresuid(0,0,0)", fn: func() error { return syscall.Setresuid(0, 0, 0) }, filter: "Uid:", expect: "\t0\t0\t0\t0"},
}
for i, v := range vs {
if err := v.fn(); err != nil {
t.Errorf("[%d] %q failed: %v", i, v.call, err)
continue
}
if err := compareStatus(v.filter, v.expect); err != nil {
t.Errorf("[%d] %q comparison: %v", i, v.call, err)
}
}
}
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