From 13f0f6069af4d49e236cbee4f0284c190784db37 Mon Sep 17 00:00:00 2001 From: Ian Gudger Date: Thu, 5 Dec 2019 17:27:15 -0800 Subject: Implement F_GETOWN_EX and F_SETOWN_EX. Some versions of glibc will convert F_GETOWN fcntl(2) calls into F_GETOWN_EX in some cases. PiperOrigin-RevId: 284089373 --- pkg/abi/linux/fcntl.go | 41 ++++++++++++++++++++++++++++------------- 1 file changed, 28 insertions(+), 13 deletions(-) (limited to 'pkg/abi/linux/fcntl.go') diff --git a/pkg/abi/linux/fcntl.go b/pkg/abi/linux/fcntl.go index f78315ebf..6663a199c 100644 --- a/pkg/abi/linux/fcntl.go +++ b/pkg/abi/linux/fcntl.go @@ -16,15 +16,17 @@ package linux // Commands from linux/fcntl.h. const ( - F_DUPFD = 0x0 - F_GETFD = 0x1 - F_SETFD = 0x2 - F_GETFL = 0x3 - F_SETFL = 0x4 - F_SETLK = 0x6 - F_SETLKW = 0x7 - F_SETOWN = 0x8 - F_GETOWN = 0x9 + F_DUPFD = 0 + F_GETFD = 1 + F_SETFD = 2 + F_GETFL = 3 + F_SETFL = 4 + F_SETLK = 6 + F_SETLKW = 7 + F_SETOWN = 8 + F_GETOWN = 9 + F_SETOWN_EX = 15 + F_GETOWN_EX = 16 F_DUPFD_CLOEXEC = 1024 + 6 F_SETPIPE_SZ = 1024 + 7 F_GETPIPE_SZ = 1024 + 8 @@ -32,9 +34,9 @@ const ( // Commands for F_SETLK. const ( - F_RDLCK = 0x0 - F_WRLCK = 0x1 - F_UNLCK = 0x2 + F_RDLCK = 0 + F_WRLCK = 1 + F_UNLCK = 2 ) // Flags for fcntl. @@ -42,7 +44,7 @@ const ( FD_CLOEXEC = 00000001 ) -// Lock structure for F_SETLK. +// Flock is the lock structure for F_SETLK. type Flock struct { Type int16 Whence int16 @@ -52,3 +54,16 @@ type Flock struct { Pid int32 _ [4]byte } + +// Flags for F_SETOWN_EX and F_GETOWN_EX. +const ( + F_OWNER_TID = 0 + F_OWNER_PID = 1 + F_OWNER_PGRP = 2 +) + +// FOwnerEx is the owner structure for F_SETOWN_EX and F_GETOWN_EX. +type FOwnerEx struct { + Type int32 + PID int32 +} -- cgit v1.2.3 From e8f1a5c1f652ba7abb8c4bd842d6afdcab03865a Mon Sep 17 00:00:00 2001 From: Dean Deng Date: Sat, 27 Jun 2020 21:32:16 -0700 Subject: Port GETOWN, SETOWN fcntls to vfs2. Also make some fixes to vfs1's F_SETOWN. The fcntl test now entirely passes on vfs2. Fixes #2920. PiperOrigin-RevId: 318669529 --- pkg/abi/linux/fcntl.go | 2 +- pkg/sentry/kernel/fasync/BUILD | 1 + pkg/sentry/kernel/fasync/fasync.go | 8 +- pkg/sentry/syscalls/linux/sys_file.go | 15 ++-- pkg/sentry/syscalls/linux/vfs2/BUILD | 1 + pkg/sentry/syscalls/linux/vfs2/fd.go | 93 ++++++++++++++++++++++ pkg/sentry/vfs/file_description.go | 74 ++++++++++++++++-- test/syscalls/linux/BUILD | 1 + test/syscalls/linux/fcntl.cc | 140 ++++++++++++++++++++++++++++++---- 9 files changed, 308 insertions(+), 27 deletions(-) (limited to 'pkg/abi/linux/fcntl.go') diff --git a/pkg/abi/linux/fcntl.go b/pkg/abi/linux/fcntl.go index 6663a199c..9242e80a5 100644 --- a/pkg/abi/linux/fcntl.go +++ b/pkg/abi/linux/fcntl.go @@ -55,7 +55,7 @@ type Flock struct { _ [4]byte } -// Flags for F_SETOWN_EX and F_GETOWN_EX. +// Owner types for F_SETOWN_EX and F_GETOWN_EX. const ( F_OWNER_TID = 0 F_OWNER_PID = 1 diff --git a/pkg/sentry/kernel/fasync/BUILD b/pkg/sentry/kernel/fasync/BUILD index b9126e946..2b3955598 100644 --- a/pkg/sentry/kernel/fasync/BUILD +++ b/pkg/sentry/kernel/fasync/BUILD @@ -11,6 +11,7 @@ go_library( "//pkg/sentry/fs", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", + "//pkg/sentry/vfs", "//pkg/sync", "//pkg/waiter", ], diff --git a/pkg/sentry/kernel/fasync/fasync.go b/pkg/sentry/kernel/fasync/fasync.go index d32c3e90a..323f1dfa5 100644 --- a/pkg/sentry/kernel/fasync/fasync.go +++ b/pkg/sentry/kernel/fasync/fasync.go @@ -20,15 +20,21 @@ import ( "gvisor.dev/gvisor/pkg/sentry/fs" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/auth" + "gvisor.dev/gvisor/pkg/sentry/vfs" "gvisor.dev/gvisor/pkg/sync" "gvisor.dev/gvisor/pkg/waiter" ) -// New creates a new FileAsync. +// New creates a new fs.FileAsync. func New() fs.FileAsync { return &FileAsync{} } +// NewVFS2 creates a new vfs.FileAsync. +func NewVFS2() vfs.FileAsync { + return &FileAsync{} +} + // FileAsync sends signals when the registered file is ready for IO. // // +stateify savable diff --git a/pkg/sentry/syscalls/linux/sys_file.go b/pkg/sentry/syscalls/linux/sys_file.go index 35eba20c5..2797c6a72 100644 --- a/pkg/sentry/syscalls/linux/sys_file.go +++ b/pkg/sentry/syscalls/linux/sys_file.go @@ -900,14 +900,20 @@ func fGetOwn(t *kernel.Task, file *fs.File) int32 { // // If who is positive, it represents a PID. If negative, it represents a PGID. // If the PID or PGID is invalid, the owner is silently unset. -func fSetOwn(t *kernel.Task, file *fs.File, who int32) { +func fSetOwn(t *kernel.Task, file *fs.File, who int32) error { a := file.Async(fasync.New).(*fasync.FileAsync) if who < 0 { + // Check for overflow before flipping the sign. + if who-1 > who { + return syserror.EINVAL + } pg := t.PIDNamespace().ProcessGroupWithID(kernel.ProcessGroupID(-who)) a.SetOwnerProcessGroup(t, pg) + } else { + tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(who)) + a.SetOwnerThreadGroup(t, tg) } - tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(who)) - a.SetOwnerThreadGroup(t, tg) + return nil } // Fcntl implements linux syscall fcntl(2). @@ -1042,8 +1048,7 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall case linux.F_GETOWN: return uintptr(fGetOwn(t, file)), nil, nil case linux.F_SETOWN: - fSetOwn(t, file, args[2].Int()) - return 0, nil, nil + return 0, nil, fSetOwn(t, file, args[2].Int()) case linux.F_GETOWN_EX: addr := args[2].Pointer() owner := fGetOwnEx(t, file) diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD index c301a0991..0c740335b 100644 --- a/pkg/sentry/syscalls/linux/vfs2/BUILD +++ b/pkg/sentry/syscalls/linux/vfs2/BUILD @@ -54,6 +54,7 @@ go_library( "//pkg/sentry/fsimpl/tmpfs", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", + "//pkg/sentry/kernel/fasync", "//pkg/sentry/kernel/pipe", "//pkg/sentry/kernel/time", "//pkg/sentry/limits", diff --git a/pkg/sentry/syscalls/linux/vfs2/fd.go b/pkg/sentry/syscalls/linux/vfs2/fd.go index e68b20bed..7e4c6a56e 100644 --- a/pkg/sentry/syscalls/linux/vfs2/fd.go +++ b/pkg/sentry/syscalls/linux/vfs2/fd.go @@ -20,6 +20,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/fs/lock" "gvisor.dev/gvisor/pkg/sentry/fsimpl/tmpfs" "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/fasync" "gvisor.dev/gvisor/pkg/sentry/kernel/pipe" slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux" "gvisor.dev/gvisor/pkg/sentry/vfs" @@ -154,6 +155,47 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return 0, nil, err } return uintptr(n), nil, nil + case linux.F_GETOWN: + a := file.AsyncHandler() + if a == nil { + return 0, nil, nil + } + owner := getAsyncOwner(t, a.(*fasync.FileAsync)) + if owner.Type == linux.F_OWNER_PGRP { + return uintptr(-owner.PID), nil, nil + } + return uintptr(owner.PID), nil, nil + case linux.F_SETOWN: + who := args[2].Int() + ownerType := int32(linux.F_OWNER_PID) + if who < 0 { + // Check for overflow before flipping the sign. + if who-1 > who { + return 0, nil, syserror.EINVAL + } + ownerType = linux.F_OWNER_PGRP + who = -who + } + a := file.SetAsyncHandler(fasync.NewVFS2).(*fasync.FileAsync) + return 0, nil, setAsyncOwner(t, a, ownerType, who) + case linux.F_GETOWN_EX: + a := file.AsyncHandler() + if a == nil { + return 0, nil, nil + } + addr := args[2].Pointer() + owner := getAsyncOwner(t, a.(*fasync.FileAsync)) + _, err := t.CopyOut(addr, &owner) + return 0, nil, err + case linux.F_SETOWN_EX: + addr := args[2].Pointer() + var owner linux.FOwnerEx + n, err := t.CopyIn(addr, &owner) + if err != nil { + return 0, nil, err + } + a := file.SetAsyncHandler(fasync.NewVFS2).(*fasync.FileAsync) + return uintptr(n), nil, setAsyncOwner(t, a, owner.Type, owner.PID) case linux.F_GETPIPE_SZ: pipefile, ok := file.Impl().(*pipe.VFSPipeFD) if !ok { @@ -177,6 +219,57 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall } } +func getAsyncOwner(t *kernel.Task, a *fasync.FileAsync) linux.FOwnerEx { + ot, otg, opg := a.Owner() + switch { + case ot != nil: + return linux.FOwnerEx{ + Type: linux.F_OWNER_TID, + PID: int32(t.PIDNamespace().IDOfTask(ot)), + } + case otg != nil: + return linux.FOwnerEx{ + Type: linux.F_OWNER_PID, + PID: int32(t.PIDNamespace().IDOfThreadGroup(otg)), + } + case opg != nil: + return linux.FOwnerEx{ + Type: linux.F_OWNER_PGRP, + PID: int32(t.PIDNamespace().IDOfProcessGroup(opg)), + } + default: + return linux.FOwnerEx{} + } +} + +func setAsyncOwner(t *kernel.Task, a *fasync.FileAsync, ownerType, pid int32) error { + switch ownerType { + case linux.F_OWNER_TID: + task := t.PIDNamespace().TaskWithID(kernel.ThreadID(pid)) + if task == nil { + return syserror.ESRCH + } + a.SetOwnerTask(t, task) + return nil + case linux.F_OWNER_PID: + tg := t.PIDNamespace().ThreadGroupWithID(kernel.ThreadID(pid)) + if tg == nil { + return syserror.ESRCH + } + a.SetOwnerThreadGroup(t, tg) + return nil + case linux.F_OWNER_PGRP: + pg := t.PIDNamespace().ProcessGroupWithID(kernel.ProcessGroupID(pid)) + if pg == nil { + return syserror.ESRCH + } + a.SetOwnerProcessGroup(t, pg) + return nil + default: + return syserror.EINVAL + } +} + func posixLock(t *kernel.Task, args arch.SyscallArguments, file *vfs.FileDescription, cmd int32) error { // Copy in the lock request. flockAddr := args[2].Pointer() diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go index e0538ea53..cd1db14ac 100644 --- a/pkg/sentry/vfs/file_description.go +++ b/pkg/sentry/vfs/file_description.go @@ -42,11 +42,20 @@ type FileDescription struct { // operations. refs int64 + // flagsMu protects statusFlags and asyncHandler below. + flagsMu sync.Mutex + // statusFlags contains status flags, "initialized by open(2) and possibly - // modified by fcntl()" - fcntl(2). statusFlags is accessed using atomic - // memory operations. + // modified by fcntl()" - fcntl(2). statusFlags can be read using atomic + // memory operations when it does not need to be synchronized with an + // access to asyncHandler. statusFlags uint32 + // asyncHandler handles O_ASYNC signal generation. It is set with the + // F_SETOWN or F_SETOWN_EX fcntls. For asyncHandler to be used, O_ASYNC must + // also be set by fcntl(2). + asyncHandler FileAsync + // epolls is the set of epollInterests registered for this FileDescription. // epolls is protected by epollMu. epollMu sync.Mutex @@ -193,6 +202,13 @@ func (fd *FileDescription) DecRef() { fd.vd.mount.EndWrite() } fd.vd.DecRef() + fd.flagsMu.Lock() + // TODO(gvisor.dev/issue/1663): We may need to unregister during save, as we do in VFS1. + if fd.statusFlags&linux.O_ASYNC != 0 && fd.asyncHandler != nil { + fd.asyncHandler.Unregister(fd) + } + fd.asyncHandler = nil + fd.flagsMu.Unlock() } else if refs < 0 { panic("FileDescription.DecRef() called without holding a reference") } @@ -276,7 +292,18 @@ func (fd *FileDescription) SetStatusFlags(ctx context.Context, creds *auth.Crede } // TODO(jamieliu): FileDescriptionImpl.SetOAsync()? const settableFlags = linux.O_APPEND | linux.O_ASYNC | linux.O_DIRECT | linux.O_NOATIME | linux.O_NONBLOCK - atomic.StoreUint32(&fd.statusFlags, (oldFlags&^settableFlags)|(flags&settableFlags)) + fd.flagsMu.Lock() + if fd.asyncHandler != nil { + // Use fd.statusFlags instead of oldFlags, which may have become outdated, + // to avoid double registering/unregistering. + if fd.statusFlags&linux.O_ASYNC == 0 && flags&linux.O_ASYNC != 0 { + fd.asyncHandler.Register(fd) + } else if fd.statusFlags&linux.O_ASYNC != 0 && flags&linux.O_ASYNC == 0 { + fd.asyncHandler.Unregister(fd) + } + } + fd.statusFlags = (oldFlags &^ settableFlags) | (flags & settableFlags) + fd.flagsMu.Unlock() return nil } @@ -533,17 +560,23 @@ func (fd *FileDescription) StatFS(ctx context.Context) (linux.Statfs, error) { return fd.impl.StatFS(ctx) } -// Readiness returns fd's I/O readiness. +// Readiness implements waiter.Waitable.Readiness. +// +// It returns fd's I/O readiness. func (fd *FileDescription) Readiness(mask waiter.EventMask) waiter.EventMask { return fd.impl.Readiness(mask) } -// EventRegister registers e for I/O readiness events in mask. +// EventRegister implements waiter.Waitable.EventRegister. +// +// It registers e for I/O readiness events in mask. func (fd *FileDescription) EventRegister(e *waiter.Entry, mask waiter.EventMask) { fd.impl.EventRegister(e, mask) } -// EventUnregister unregisters e for I/O readiness events. +// EventUnregister implements waiter.Waitable.EventUnregister. +// +// It unregisters e for I/O readiness events. func (fd *FileDescription) EventUnregister(e *waiter.Entry) { fd.impl.EventUnregister(e) } @@ -770,3 +803,32 @@ func (fd *FileDescription) LockPOSIX(ctx context.Context, uid lock.UniqueID, t l func (fd *FileDescription) UnlockPOSIX(ctx context.Context, uid lock.UniqueID, start, end uint64, whence int16) error { return fd.impl.UnlockPOSIX(ctx, uid, start, end, whence) } + +// A FileAsync sends signals to its owner when w is ready for IO. This is only +// implemented by pkg/sentry/fasync:FileAsync, but we unfortunately need this +// interface to avoid circular dependencies. +type FileAsync interface { + Register(w waiter.Waitable) + Unregister(w waiter.Waitable) +} + +// AsyncHandler returns the FileAsync for fd. +func (fd *FileDescription) AsyncHandler() FileAsync { + fd.flagsMu.Lock() + defer fd.flagsMu.Unlock() + return fd.asyncHandler +} + +// SetAsyncHandler sets fd.asyncHandler if it has not been set before and +// returns it. +func (fd *FileDescription) SetAsyncHandler(newHandler func() FileAsync) FileAsync { + fd.flagsMu.Lock() + defer fd.flagsMu.Unlock() + if fd.asyncHandler == nil { + fd.asyncHandler = newHandler() + if fd.statusFlags&linux.O_ASYNC != 0 { + fd.asyncHandler.Register(fd) + } + } + return fd.asyncHandler +} diff --git a/test/syscalls/linux/BUILD b/test/syscalls/linux/BUILD index 270b9e4c4..e141a86bb 100644 --- a/test/syscalls/linux/BUILD +++ b/test/syscalls/linux/BUILD @@ -805,6 +805,7 @@ cc_binary( "//test/util:save_util", "//test/util:temp_path", "//test/util:test_util", + "//test/util:thread_util", "//test/util:timer_util", ], ) diff --git a/test/syscalls/linux/fcntl.cc b/test/syscalls/linux/fcntl.cc index 25bef2522..9130618fa 100644 --- a/test/syscalls/linux/fcntl.cc +++ b/test/syscalls/linux/fcntl.cc @@ -37,6 +37,7 @@ #include "test/util/save_util.h" #include "test/util/temp_path.h" #include "test/util/test_util.h" +#include "test/util/thread_util.h" #include "test/util/timer_util.h" ABSL_FLAG(std::string, child_setlock_on, "", @@ -953,15 +954,18 @@ TEST(FcntlTest, DupAfterO_ASYNC) { EXPECT_EQ(after & O_ASYNC, O_ASYNC); } -TEST(FcntlTest, GetOwn) { +TEST(FcntlTest, GetOwnNone) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); - EXPECT_EQ(syscall(__NR_fcntl, s.get(), F_GETOWN), 0); + // Use the raw syscall because the glibc wrapper may convert F_{GET,SET}OWN + // into F_{GET,SET}OWN_EX. + EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN), + SyscallSucceedsWithValue(0)); MaybeSave(); } -TEST(FcntlTest, GetOwnEx) { +TEST(FcntlTest, GetOwnExNone) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); @@ -970,6 +974,70 @@ TEST(FcntlTest, GetOwnEx) { SyscallSucceedsWithValue(0)); } +TEST(FcntlTest, SetOwnInvalidPid) { + SKIP_IF(IsRunningWithVFS1()); + + FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( + Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); + + EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, 12345678), + SyscallFailsWithErrno(ESRCH)); +} + +TEST(FcntlTest, SetOwnInvalidPgrp) { + SKIP_IF(IsRunningWithVFS1()); + + FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( + Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); + + EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, -12345678), + SyscallFailsWithErrno(ESRCH)); +} + +TEST(FcntlTest, SetOwnPid) { + FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( + Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); + + pid_t pid; + EXPECT_THAT(pid = getpid(), SyscallSucceeds()); + + ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, pid), SyscallSucceeds()); + + EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN), + SyscallSucceedsWithValue(pid)); + MaybeSave(); +} + +TEST(FcntlTest, SetOwnPgrp) { + FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( + Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); + + pid_t pgid; + EXPECT_THAT(pgid = getpgrp(), SyscallSucceeds()); + + ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, -pgid), SyscallSucceeds()); + + // Verify with F_GETOWN_EX; using F_GETOWN on Linux may incorrectly treat the + // negative return value as an error, converting the return value to -1 and + // setting errno accordingly. + f_owner_ex got_owner = {}; + ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN_EX, &got_owner), + SyscallSucceedsWithValue(0)); + EXPECT_EQ(got_owner.type, F_OWNER_PGRP); + EXPECT_EQ(got_owner.pid, pgid); + MaybeSave(); +} + +// F_SETOWN flips the sign of negative values, an operation that is guarded +// against overflow. +TEST(FcntlTest, SetOwnOverflow) { + FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( + Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); + + EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, INT_MIN), + SyscallFailsWithErrno(EINVAL)); +} + TEST(FcntlTest, SetOwnExInvalidType) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); @@ -1027,7 +1095,8 @@ TEST(FcntlTest, SetOwnExTid) { ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), SyscallSucceeds()); - EXPECT_EQ(syscall(__NR_fcntl, s.get(), F_GETOWN), owner.pid); + EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN), + SyscallSucceedsWithValue(owner.pid)); MaybeSave(); } @@ -1042,7 +1111,8 @@ TEST(FcntlTest, SetOwnExPid) { ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), SyscallSucceeds()); - EXPECT_EQ(syscall(__NR_fcntl, s.get(), F_GETOWN), owner.pid); + EXPECT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN), + SyscallSucceedsWithValue(owner.pid)); MaybeSave(); } @@ -1050,18 +1120,21 @@ TEST(FcntlTest, SetOwnExPgrp) { FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); - f_owner_ex owner = {}; - owner.type = F_OWNER_PGRP; - EXPECT_THAT(owner.pid = getpgrp(), SyscallSucceeds()); + f_owner_ex set_owner = {}; + set_owner.type = F_OWNER_PGRP; + EXPECT_THAT(set_owner.pid = getpgrp(), SyscallSucceeds()); - ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &owner), + ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN_EX, &set_owner), SyscallSucceeds()); - // NOTE(igudger): I don't understand why, but this is flaky on Linux. - // GetOwnExPgrp (below) does not have this issue. - SKIP_IF(!IsRunningOnGvisor()); - - EXPECT_EQ(syscall(__NR_fcntl, s.get(), F_GETOWN), -owner.pid); + // Verify with F_GETOWN_EX; using F_GETOWN on Linux may incorrectly treat the + // negative return value as an error, converting the return value to -1 and + // setting errno accordingly. + f_owner_ex got_owner = {}; + ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_GETOWN_EX, &got_owner), + SyscallSucceedsWithValue(0)); + EXPECT_EQ(got_owner.type, set_owner.type); + EXPECT_EQ(got_owner.pid, set_owner.pid); MaybeSave(); } @@ -1119,6 +1192,45 @@ TEST(FcntlTest, GetOwnExPgrp) { EXPECT_EQ(got_owner.pid, set_owner.pid); } +// Make sure that making multiple concurrent changes to async signal generation +// does not cause any race issues. +TEST(FcntlTest, SetFlSetOwnDoNotRace) { + FileDescriptor s = ASSERT_NO_ERRNO_AND_VALUE( + Socket(AF_UNIX, SOCK_SEQPACKET | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)); + + pid_t pid; + EXPECT_THAT(pid = getpid(), SyscallSucceeds()); + + constexpr absl::Duration runtime = absl::Milliseconds(300); + auto setAsync = [&s, &runtime] { + for (auto start = absl::Now(); absl::Now() - start < runtime;) { + ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETFL, O_ASYNC), + SyscallSucceeds()); + sched_yield(); + } + }; + auto resetAsync = [&s, &runtime] { + for (auto start = absl::Now(); absl::Now() - start < runtime;) { + ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETFL, 0), SyscallSucceeds()); + sched_yield(); + } + }; + auto setOwn = [&s, &pid, &runtime] { + for (auto start = absl::Now(); absl::Now() - start < runtime;) { + ASSERT_THAT(syscall(__NR_fcntl, s.get(), F_SETOWN, pid), + SyscallSucceeds()); + sched_yield(); + } + }; + + std::list threads; + for (int i = 0; i < 10; i++) { + threads.emplace_back(setAsync); + threads.emplace_back(resetAsync); + threads.emplace_back(setOwn); + } +} + } // namespace } // namespace testing -- cgit v1.2.3