syscall_unix_test.go

Documentation: syscall

		 1  // Copyright 2013 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  //go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
		 6  // +build aix darwin dragonfly freebsd linux netbsd openbsd solaris
		 7  
		 8  package syscall_test
		 9  
		10  import (
		11  	"flag"
		12  	"fmt"
		13  	"internal/testenv"
		14  	"io"
		15  	"net"
		16  	"os"
		17  	"os/exec"
		18  	"path/filepath"
		19  	"runtime"
		20  	"strconv"
		21  	"syscall"
		22  	"testing"
		23  	"time"
		24  )
		25  
		26  // Tests that below functions, structures and constants are consistent
		27  // on all Unix-like systems.
		28  func _() {
		29  	// program scheduling priority functions and constants
		30  	var (
		31  		_ func(int, int, int) error	 = syscall.Setpriority
		32  		_ func(int, int) (int, error) = syscall.Getpriority
		33  	)
		34  	const (
		35  		_ int = syscall.PRIO_USER
		36  		_ int = syscall.PRIO_PROCESS
		37  		_ int = syscall.PRIO_PGRP
		38  	)
		39  
		40  	// termios constants
		41  	const (
		42  		_ int = syscall.TCIFLUSH
		43  		_ int = syscall.TCIOFLUSH
		44  		_ int = syscall.TCOFLUSH
		45  	)
		46  
		47  	// fcntl file locking structure and constants
		48  	var (
		49  		_ = syscall.Flock_t{
		50  			Type:	 int16(0),
		51  			Whence: int16(0),
		52  			Start:	int64(0),
		53  			Len:		int64(0),
		54  			Pid:		int32(0),
		55  		}
		56  	)
		57  	const (
		58  		_ = syscall.F_GETLK
		59  		_ = syscall.F_SETLK
		60  		_ = syscall.F_SETLKW
		61  	)
		62  }
		63  
		64  // TestFcntlFlock tests whether the file locking structure matches
		65  // the calling convention of each kernel.
		66  // On some Linux systems, glibc uses another set of values for the
		67  // commands and translates them to the correct value that the kernel
		68  // expects just before the actual fcntl syscall. As Go uses raw
		69  // syscalls directly, it must use the real value, not the glibc value.
		70  // Thus this test also verifies that the Flock_t structure can be
		71  // roundtripped with F_SETLK and F_GETLK.
		72  func TestFcntlFlock(t *testing.T) {
		73  	if runtime.GOOS == "ios" {
		74  		t.Skip("skipping; no child processes allowed on iOS")
		75  	}
		76  	flock := syscall.Flock_t{
		77  		Type:	syscall.F_WRLCK,
		78  		Start: 31415, Len: 271828, Whence: 1,
		79  	}
		80  	if os.Getenv("GO_WANT_HELPER_PROCESS") == "" {
		81  		// parent
		82  		tempDir := t.TempDir()
		83  		name := filepath.Join(tempDir, "TestFcntlFlock")
		84  		fd, err := syscall.Open(name, syscall.O_CREAT|syscall.O_RDWR|syscall.O_CLOEXEC, 0)
		85  		if err != nil {
		86  			t.Fatalf("Open failed: %v", err)
		87  		}
		88  		defer syscall.Close(fd)
		89  		if err := syscall.Ftruncate(fd, 1<<20); err != nil {
		90  			t.Fatalf("Ftruncate(1<<20) failed: %v", err)
		91  		}
		92  		if err := syscall.FcntlFlock(uintptr(fd), syscall.F_SETLK, &flock); err != nil {
		93  			t.Fatalf("FcntlFlock(F_SETLK) failed: %v", err)
		94  		}
		95  		cmd := exec.Command(os.Args[0], "-test.run=^TestFcntlFlock$")
		96  		cmd.Env = append(os.Environ(), "GO_WANT_HELPER_PROCESS=1")
		97  		cmd.ExtraFiles = []*os.File{os.NewFile(uintptr(fd), name)}
		98  		out, err := cmd.CombinedOutput()
		99  		if len(out) > 0 || err != nil {
	 100  			t.Fatalf("child process: %q, %v", out, err)
	 101  		}
	 102  	} else {
	 103  		// child
	 104  		got := flock
	 105  		// make sure the child lock is conflicting with the parent lock
	 106  		got.Start--
	 107  		got.Len++
	 108  		if err := syscall.FcntlFlock(3, syscall.F_GETLK, &got); err != nil {
	 109  			t.Fatalf("FcntlFlock(F_GETLK) failed: %v", err)
	 110  		}
	 111  		flock.Pid = int32(syscall.Getppid())
	 112  		// Linux kernel always set Whence to 0
	 113  		flock.Whence = 0
	 114  		if got.Type == flock.Type && got.Start == flock.Start && got.Len == flock.Len && got.Pid == flock.Pid && got.Whence == flock.Whence {
	 115  			os.Exit(0)
	 116  		}
	 117  		t.Fatalf("FcntlFlock got %v, want %v", got, flock)
	 118  	}
	 119  }
	 120  
	 121  // TestPassFD tests passing a file descriptor over a Unix socket.
	 122  //
	 123  // This test involved both a parent and child process. The parent
	 124  // process is invoked as a normal test, with "go test", which then
	 125  // runs the child process by running the current test binary with args
	 126  // "-test.run=^TestPassFD$" and an environment variable used to signal
	 127  // that the test should become the child process instead.
	 128  func TestPassFD(t *testing.T) {
	 129  	testenv.MustHaveExec(t)
	 130  
	 131  	if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
	 132  		passFDChild()
	 133  		return
	 134  	}
	 135  
	 136  	if runtime.GOOS == "aix" {
	 137  		// Unix network isn't properly working on AIX 7.2 with Technical Level < 2
	 138  		out, err := exec.Command("oslevel", "-s").Output()
	 139  		if err != nil {
	 140  			t.Skipf("skipping on AIX because oslevel -s failed: %v", err)
	 141  		}
	 142  		if len(out) < len("7200-XX-ZZ-YYMM") { // AIX 7.2, Tech Level XX, Service Pack ZZ, date YYMM
	 143  			t.Skip("skipping on AIX because oslevel -s hasn't the right length")
	 144  		}
	 145  		aixVer := string(out[:4])
	 146  		tl, err := strconv.Atoi(string(out[5:7]))
	 147  		if err != nil {
	 148  			t.Skipf("skipping on AIX because oslevel -s output cannot be parsed: %v", err)
	 149  		}
	 150  		if aixVer < "7200" || (aixVer == "7200" && tl < 2) {
	 151  			t.Skip("skipped on AIX versions previous to 7.2 TL 2")
	 152  		}
	 153  
	 154  	}
	 155  
	 156  	tempDir := t.TempDir()
	 157  
	 158  	fds, err := syscall.Socketpair(syscall.AF_LOCAL, syscall.SOCK_STREAM, 0)
	 159  	if err != nil {
	 160  		t.Fatalf("Socketpair: %v", err)
	 161  	}
	 162  	writeFile := os.NewFile(uintptr(fds[0]), "child-writes")
	 163  	readFile := os.NewFile(uintptr(fds[1]), "parent-reads")
	 164  	defer writeFile.Close()
	 165  	defer readFile.Close()
	 166  
	 167  	cmd := exec.Command(os.Args[0], "-test.run=^TestPassFD$", "--", tempDir)
	 168  	cmd.Env = append(os.Environ(), "GO_WANT_HELPER_PROCESS=1")
	 169  	cmd.ExtraFiles = []*os.File{writeFile}
	 170  
	 171  	out, err := cmd.CombinedOutput()
	 172  	if len(out) > 0 || err != nil {
	 173  		t.Fatalf("child process: %q, %v", out, err)
	 174  	}
	 175  
	 176  	c, err := net.FileConn(readFile)
	 177  	if err != nil {
	 178  		t.Fatalf("FileConn: %v", err)
	 179  	}
	 180  	defer c.Close()
	 181  
	 182  	uc, ok := c.(*net.UnixConn)
	 183  	if !ok {
	 184  		t.Fatalf("unexpected FileConn type; expected UnixConn, got %T", c)
	 185  	}
	 186  
	 187  	buf := make([]byte, 32) // expect 1 byte
	 188  	oob := make([]byte, 32) // expect 24 bytes
	 189  	closeUnix := time.AfterFunc(5*time.Second, func() {
	 190  		t.Logf("timeout reading from unix socket")
	 191  		uc.Close()
	 192  	})
	 193  	_, oobn, _, _, err := uc.ReadMsgUnix(buf, oob)
	 194  	if err != nil {
	 195  		t.Fatalf("ReadMsgUnix: %v", err)
	 196  	}
	 197  	closeUnix.Stop()
	 198  
	 199  	scms, err := syscall.ParseSocketControlMessage(oob[:oobn])
	 200  	if err != nil {
	 201  		t.Fatalf("ParseSocketControlMessage: %v", err)
	 202  	}
	 203  	if len(scms) != 1 {
	 204  		t.Fatalf("expected 1 SocketControlMessage; got scms = %#v", scms)
	 205  	}
	 206  	scm := scms[0]
	 207  	gotFds, err := syscall.ParseUnixRights(&scm)
	 208  	if err != nil {
	 209  		t.Fatalf("syscall.ParseUnixRights: %v", err)
	 210  	}
	 211  	if len(gotFds) != 1 {
	 212  		t.Fatalf("wanted 1 fd; got %#v", gotFds)
	 213  	}
	 214  
	 215  	f := os.NewFile(uintptr(gotFds[0]), "fd-from-child")
	 216  	defer f.Close()
	 217  
	 218  	got, err := io.ReadAll(f)
	 219  	want := "Hello from child process!\n"
	 220  	if string(got) != want {
	 221  		t.Errorf("child process ReadAll: %q, %v; want %q", got, err, want)
	 222  	}
	 223  }
	 224  
	 225  // passFDChild is the child process used by TestPassFD.
	 226  func passFDChild() {
	 227  	defer os.Exit(0)
	 228  
	 229  	// Look for our fd. It should be fd 3, but we work around an fd leak
	 230  	// bug here (https://golang.org/issue/2603) to let it be elsewhere.
	 231  	var uc *net.UnixConn
	 232  	for fd := uintptr(3); fd <= 10; fd++ {
	 233  		f := os.NewFile(fd, "unix-conn")
	 234  		var ok bool
	 235  		netc, _ := net.FileConn(f)
	 236  		uc, ok = netc.(*net.UnixConn)
	 237  		if ok {
	 238  			break
	 239  		}
	 240  	}
	 241  	if uc == nil {
	 242  		fmt.Println("failed to find unix fd")
	 243  		return
	 244  	}
	 245  
	 246  	// Make a file f to send to our parent process on uc.
	 247  	// We make it in tempDir, which our parent will clean up.
	 248  	flag.Parse()
	 249  	tempDir := flag.Arg(0)
	 250  	f, err := os.CreateTemp(tempDir, "")
	 251  	if err != nil {
	 252  		fmt.Printf("TempFile: %v", err)
	 253  		return
	 254  	}
	 255  
	 256  	f.Write([]byte("Hello from child process!\n"))
	 257  	f.Seek(0, io.SeekStart)
	 258  
	 259  	rights := syscall.UnixRights(int(f.Fd()))
	 260  	dummyByte := []byte("x")
	 261  	n, oobn, err := uc.WriteMsgUnix(dummyByte, rights, nil)
	 262  	if err != nil {
	 263  		fmt.Printf("WriteMsgUnix: %v", err)
	 264  		return
	 265  	}
	 266  	if n != 1 || oobn != len(rights) {
	 267  		fmt.Printf("WriteMsgUnix = %d, %d; want 1, %d", n, oobn, len(rights))
	 268  		return
	 269  	}
	 270  }
	 271  
	 272  // TestUnixRightsRoundtrip tests that UnixRights, ParseSocketControlMessage,
	 273  // and ParseUnixRights are able to successfully round-trip lists of file descriptors.
	 274  func TestUnixRightsRoundtrip(t *testing.T) {
	 275  	testCases := [...][][]int{
	 276  		{{42}},
	 277  		{{1, 2}},
	 278  		{{3, 4, 5}},
	 279  		{{}},
	 280  		{{1, 2}, {3, 4, 5}, {}, {7}},
	 281  	}
	 282  	for _, testCase := range testCases {
	 283  		b := []byte{}
	 284  		var n int
	 285  		for _, fds := range testCase {
	 286  			// Last assignment to n wins
	 287  			n = len(b) + syscall.CmsgLen(4*len(fds))
	 288  			b = append(b, syscall.UnixRights(fds...)...)
	 289  		}
	 290  		// Truncate b
	 291  		b = b[:n]
	 292  
	 293  		scms, err := syscall.ParseSocketControlMessage(b)
	 294  		if err != nil {
	 295  			t.Fatalf("ParseSocketControlMessage: %v", err)
	 296  		}
	 297  		if len(scms) != len(testCase) {
	 298  			t.Fatalf("expected %v SocketControlMessage; got scms = %#v", len(testCase), scms)
	 299  		}
	 300  		for i, scm := range scms {
	 301  			gotFds, err := syscall.ParseUnixRights(&scm)
	 302  			if err != nil {
	 303  				t.Fatalf("ParseUnixRights: %v", err)
	 304  			}
	 305  			wantFds := testCase[i]
	 306  			if len(gotFds) != len(wantFds) {
	 307  				t.Fatalf("expected %v fds, got %#v", len(wantFds), gotFds)
	 308  			}
	 309  			for j, fd := range gotFds {
	 310  				if fd != wantFds[j] {
	 311  					t.Fatalf("expected fd %v, got %v", wantFds[j], fd)
	 312  				}
	 313  			}
	 314  		}
	 315  	}
	 316  }
	 317  
	 318  func TestRlimit(t *testing.T) {
	 319  	var rlimit, zero syscall.Rlimit
	 320  	err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rlimit)
	 321  	if err != nil {
	 322  		t.Fatalf("Getrlimit: save failed: %v", err)
	 323  	}
	 324  	if zero == rlimit {
	 325  		t.Fatalf("Getrlimit: save failed: got zero value %#v", rlimit)
	 326  	}
	 327  	set := rlimit
	 328  	set.Cur = set.Max - 1
	 329  	if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && set.Cur > 4096 {
	 330  		// rlim_min for RLIMIT_NOFILE should be equal to
	 331  		// or lower than kern.maxfilesperproc, which on
	 332  		// some machines are 4096. See #40564.
	 333  		set.Cur = 4096
	 334  	}
	 335  	err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &set)
	 336  	if err != nil {
	 337  		t.Fatalf("Setrlimit: set failed: %#v %v", set, err)
	 338  	}
	 339  	var get syscall.Rlimit
	 340  	err = syscall.Getrlimit(syscall.RLIMIT_NOFILE, &get)
	 341  	if err != nil {
	 342  		t.Fatalf("Getrlimit: get failed: %v", err)
	 343  	}
	 344  	set = rlimit
	 345  	set.Cur = set.Max - 1
	 346  	if (runtime.GOOS == "darwin" || runtime.GOOS == "ios") && set.Cur > 4096 {
	 347  		set.Cur = 4096
	 348  	}
	 349  	if set != get {
	 350  		t.Fatalf("Rlimit: change failed: wanted %#v got %#v", set, get)
	 351  	}
	 352  	err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rlimit)
	 353  	if err != nil {
	 354  		t.Fatalf("Setrlimit: restore failed: %#v %v", rlimit, err)
	 355  	}
	 356  }
	 357  
	 358  func TestSeekFailure(t *testing.T) {
	 359  	_, err := syscall.Seek(-1, 0, io.SeekStart)
	 360  	if err == nil {
	 361  		t.Fatalf("Seek(-1, 0, 0) did not fail")
	 362  	}
	 363  	str := err.Error() // used to crash on Linux
	 364  	t.Logf("Seek: %v", str)
	 365  	if str == "" {
	 366  		t.Fatalf("Seek(-1, 0, 0) return error with empty message")
	 367  	}
	 368  }
	 369  
	 370  func TestSetsockoptString(t *testing.T) {
	 371  	// should not panic on empty string, see issue #31277
	 372  	err := syscall.SetsockoptString(-1, 0, 0, "")
	 373  	if err == nil {
	 374  		t.Fatalf("SetsockoptString: did not fail")
	 375  	}
	 376  }
	 377  
	 378  func TestENFILETemporary(t *testing.T) {
	 379  	if !syscall.ENFILE.Temporary() {
	 380  		t.Error("ENFILE is not treated as a temporary error")
	 381  	}
	 382  }
	 383
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