netbird/gvisor
0
0
Fork 0
mirror of https://github.com/netbirdio/gvisor.git synced 2026-05-22 17:12:49 -07:00
Code Issues Packages Projects Releases Wiki Activity

Implement IN_EXCL_UNLINK inotify option in vfs2.

Browse Source 
Limited to tmpfs. Inotify support in other filesystem implementations to
follow.

Updates #1479

PiperOrigin-RevId: 313828648
This commit is contained in:
Dean Deng
2020-05-29 12:28:49 -07:00
committed by gVisor bot
parent 0baba92ad9
commit ccf69bdd7e
13 changed files with 235 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files
pkg/sentry/fsimpl/ext/dentry.go
+1 -1
View File
@@ -64,7 +64,7 @@ func (d *dentry) DecRef() {
// InotifyWithParent implements vfs.DentryImpl.InotifyWithParent.
//
// TODO(gvisor.dev/issue/1479): Implement inotify.
func (d *dentry) InotifyWithParent(events uint32, cookie uint32) {}
func (d *dentry) InotifyWithParent(events uint32, cookie uint32, et vfs.EventType) {}
// Watches implements vfs.DentryImpl.Watches.
//
pkg/sentry/fsimpl/gofer/gofer.go
+1 -1
View File
@@ -1042,7 +1042,7 @@ func (d *dentry) decRefLocked() {
// InotifyWithParent implements vfs.DentryImpl.InotifyWithParent.
//
// TODO(gvisor.dev/issue/1479): Implement inotify.
func (d *dentry) InotifyWithParent(events uint32, cookie uint32) {}
func (d *dentry) InotifyWithParent(events uint32, cookie uint32, et vfs.EventType) {}
// Watches implements vfs.DentryImpl.Watches.
//
pkg/sentry/fsimpl/kernfs/kernfs.go
+1 -1
View File
@@ -228,7 +228,7 @@ func (d *Dentry) destroy() {
// InotifyWithParent implements vfs.DentryImpl.InotifyWithParent.
//
// TODO(gvisor.dev/issue/1479): Implement inotify.
func (d *Dentry) InotifyWithParent(events uint32, cookie uint32) {}
func (d *Dentry) InotifyWithParent(events uint32, cookie uint32, et vfs.EventType) {}
// Watches implements vfs.DentryImpl.Watches.
//
pkg/sentry/fsimpl/tmpfs/directory.go
+2 -1
View File
@@ -79,6 +79,7 @@ func (dir *directory) removeChildLocked(child *dentry) {
dir.iterMu.Lock()
dir.childList.Remove(child)
dir.iterMu.Unlock()
child.unlinked = true
}
type directoryFD struct {
@@ -112,7 +113,7 @@ func (fd *directoryFD) IterDirents(ctx context.Context, cb vfs.IterDirentsCallba
dir.iterMu.Lock()
defer dir.iterMu.Unlock()
fd.dentry().InotifyWithParent(linux.IN_ACCESS, 0)
fd.dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
fd.inode().touchAtime(fd.vfsfd.Mount())
if fd.off == 0 {
pkg/sentry/fsimpl/tmpfs/filesystem.go
+7 -7
View File
@@ -182,7 +182,7 @@ func (fs *filesystem) doCreateAt(rp *vfs.ResolvingPath, dir bool, create func(pa
if dir {
ev |= linux.IN_ISDIR
}
parentDir.inode.watches.Notify(name, uint32(ev), 0)
parentDir.inode.watches.Notify(name, uint32(ev), 0, vfs.InodeEvent)
parentDir.inode.touchCMtime()
return nil
}
@@ -247,7 +247,7 @@ func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.
return syserror.EMLINK
}
d.inode.incLinksLocked()
d.inode.watches.Notify("", linux.IN_ATTRIB, 0)
d.inode.watches.Notify("", linux.IN_ATTRIB, 0, vfs.InodeEvent)
parentDir.insertChildLocked(fs.newDentry(d.inode), name)
return nil
})
@@ -361,7 +361,7 @@ afterTrailingSymlink:
if err != nil {
return nil, err
}
parentDir.inode.watches.Notify(name, linux.IN_CREATE, 0)
parentDir.inode.watches.Notify(name, linux.IN_CREATE, 0, vfs.PathEvent)
parentDir.inode.touchCMtime()
return fd, nil
}
@@ -613,7 +613,7 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error
return err
}
parentDir.removeChildLocked(child)
parentDir.inode.watches.Notify(name, linux.IN_DELETE|linux.IN_ISDIR, 0)
parentDir.inode.watches.Notify(name, linux.IN_DELETE|linux.IN_ISDIR, 0, vfs.InodeEvent)
// Remove links for child, child/., and child/..
child.inode.decLinksLocked()
child.inode.decLinksLocked()
@@ -636,7 +636,7 @@ func (fs *filesystem) SetStatAt(ctx context.Context, rp *vfs.ResolvingPath, opts
}
if ev := vfs.InotifyEventFromStatMask(opts.Stat.Mask); ev != 0 {
d.InotifyWithParent(ev, 0)
d.InotifyWithParent(ev, 0, vfs.InodeEvent)
}
return nil
}
@@ -784,7 +784,7 @@ func (fs *filesystem) SetxattrAt(ctx context.Context, rp *vfs.ResolvingPath, opt
return err
}
d.InotifyWithParent(linux.IN_ATTRIB, 0)
d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
return nil
}
@@ -800,7 +800,7 @@ func (fs *filesystem) RemovexattrAt(ctx context.Context, rp *vfs.ResolvingPath,
return err
}
d.InotifyWithParent(linux.IN_ATTRIB, 0)
d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
return nil
}
pkg/sentry/fsimpl/tmpfs/tmpfs.go
+11 -7
View File
@@ -163,6 +163,11 @@ type dentry struct {
// filesystem.mu.
name string
// unlinked indicates whether this dentry has been unlinked from its parent.
// It is only set to true on an unlink operation, and never set from true to
// false. unlinked is protected by filesystem.mu.
unlinked bool
// dentryEntry (ugh) links dentries into their parent directory.childList.
dentryEntry
@@ -202,7 +207,7 @@ func (d *dentry) DecRef() {
}
// InotifyWithParent implements vfs.DentryImpl.InotifyWithParent.
func (d *dentry) InotifyWithParent(events uint32, cookie uint32) {
func (d *dentry) InotifyWithParent(events uint32, cookie uint32, et vfs.EventType) {
if d.inode.isDir() {
events |= linux.IN_ISDIR
}
@@ -211,9 +216,9 @@ func (d *dentry) InotifyWithParent(events uint32, cookie uint32) {
if d.parent != nil {
// Note that d.parent or d.name may be stale if there is a concurrent
// rename operation. Inotify does not provide consistency guarantees.
d.parent.inode.watches.Notify(d.name, events, cookie)
d.parent.inode.watches.NotifyWithExclusions(d.name, events, cookie, et, d.unlinked)
}
d.inode.watches.Notify("", events, cookie)
d.inode.watches.Notify("", events, cookie, et)
}
// Watches implements vfs.DentryImpl.Watches.
@@ -676,9 +681,8 @@ func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions)
return err
}
// Generate inotify events.
if ev := vfs.InotifyEventFromStatMask(opts.Stat.Mask); ev != 0 {
d.InotifyWithParent(ev, 0)
d.InotifyWithParent(ev, 0, vfs.InodeEvent)
}
return nil
}
@@ -701,7 +705,7 @@ func (fd *fileDescription) Setxattr(ctx context.Context, opts vfs.SetxattrOption
}
// Generate inotify events.
d.InotifyWithParent(linux.IN_ATTRIB, 0)
d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
return nil
}
@@ -713,7 +717,7 @@ func (fd *fileDescription) Removexattr(ctx context.Context, name string) error {
}
// Generate inotify events.
d.InotifyWithParent(linux.IN_ATTRIB, 0)
d.InotifyWithParent(linux.IN_ATTRIB, 0, vfs.InodeEvent)
return nil
}
pkg/sentry/kernel/fd_table.go
+1 -1
View File
@@ -158,7 +158,7 @@ func (f *FDTable) dropVFS2(file *vfs.FileDescription) {
if file.IsWritable() {
ev = linux.IN_CLOSE_WRITE
}
file.Dentry().InotifyWithParent(ev, 0)
file.Dentry().InotifyWithParent(ev, 0, vfs.PathEvent)
// Drop the table reference.
file.DecRef()
pkg/sentry/syscalls/linux/vfs2/read_write.go
+12 -12
View File
@@ -94,7 +94,7 @@ func read(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, opt
n, err := file.Read(t, dst, opts)
if err != syserror.ErrWouldBlock {
if n > 0 {
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0)
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
}
return n, err
}
@@ -102,7 +102,7 @@ func read(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, opt
allowBlock, deadline, hasDeadline := blockPolicy(t, file)
if !allowBlock {
if n > 0 {
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0)
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
}
return n, err
}
@@ -135,7 +135,7 @@ func read(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, opt
file.EventUnregister(&w)
if total > 0 {
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0)
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
}
return total, err
}
@@ -258,7 +258,7 @@ func pread(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, of
n, err := file.PRead(t, dst, offset, opts)
if err != syserror.ErrWouldBlock {
if n > 0 {
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0)
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
}
return n, err
}
@@ -266,7 +266,7 @@ func pread(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, of
allowBlock, deadline, hasDeadline := blockPolicy(t, file)
if !allowBlock {
if n > 0 {
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0)
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
}
return n, err
}
@@ -299,7 +299,7 @@ func pread(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, of
file.EventUnregister(&w)
if total > 0 {
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0)
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
}
return total, err
}
@@ -364,7 +364,7 @@ func write(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, op
n, err := file.Write(t, src, opts)
if err != syserror.ErrWouldBlock {
if n > 0 {
file.Dentry().InotifyWithParent(linux.IN_MODIFY, 0)
file.Dentry().InotifyWithParent(linux.IN_MODIFY, 0, vfs.PathEvent)
}
return n, err
}
@@ -372,7 +372,7 @@ func write(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, op
allowBlock, deadline, hasDeadline := blockPolicy(t, file)
if !allowBlock {
if n > 0 {
file.Dentry().InotifyWithParent(linux.IN_MODIFY, 0)
file.Dentry().InotifyWithParent(linux.IN_MODIFY, 0, vfs.PathEvent)
}
return n, err
}
@@ -405,7 +405,7 @@ func write(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, op
file.EventUnregister(&w)
if total > 0 {
file.Dentry().InotifyWithParent(linux.IN_MODIFY, 0)
file.Dentry().InotifyWithParent(linux.IN_MODIFY, 0, vfs.PathEvent)
}
return total, err
}
@@ -528,7 +528,7 @@ func pwrite(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, o
n, err := file.PWrite(t, src, offset, opts)
if err != syserror.ErrWouldBlock {
if n > 0 {
file.Dentry().InotifyWithParent(linux.IN_MODIFY, 0)
file.Dentry().InotifyWithParent(linux.IN_MODIFY, 0, vfs.PathEvent)
}
return n, err
}
@@ -536,7 +536,7 @@ func pwrite(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, o
allowBlock, deadline, hasDeadline := blockPolicy(t, file)
if !allowBlock {
if n > 0 {
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0)
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
}
return n, err
}
@@ -569,7 +569,7 @@ func pwrite(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, o
file.EventUnregister(&w)
if total > 0 {
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0)
file.Dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
}
return total, err
}
pkg/sentry/vfs/anonfs.go
+1 -1
View File
@@ -301,7 +301,7 @@ func (d *anonDentry) DecRef() {
// InotifyWithParent implements DentryImpl.InotifyWithParent.
//
// TODO(gvisor.dev/issue/1479): Implement inotify.
func (d *anonDentry) InotifyWithParent(events uint32, cookie uint32) {}
func (d *anonDentry) InotifyWithParent(events uint32, cookie uint32, et EventType) {}
// Watches implements DentryImpl.Watches.
//
pkg/sentry/vfs/dentry.go
+3 -3
View File
@@ -113,7 +113,7 @@ type DentryImpl interface {
//
// Note that the events may not actually propagate up to the user, depending
// on the event masks.
InotifyWithParent(events uint32, cookie uint32)
InotifyWithParent(events uint32, cookie uint32, et EventType)
// Watches returns the set of inotify watches for the file corresponding to
// the Dentry. Dentries that are hard links to the same underlying file
@@ -151,8 +151,8 @@ func (d *Dentry) isMounted() bool {
// InotifyWithParent notifies all watches on the inodes for this dentry and
// its parent of events.
func (d *Dentry) InotifyWithParent(events uint32, cookie uint32) {
d.impl.InotifyWithParent(events, cookie)
func (d *Dentry) InotifyWithParent(events uint32, cookie uint32, et EventType) {
d.impl.InotifyWithParent(events, cookie, et)
}
// Watches returns the set of inotify watches associated with d.
pkg/sentry/vfs/inotify.go
+30 -8
View File
@@ -33,6 +33,19 @@ import (
// must be a power 2 for rounding below.
const inotifyEventBaseSize = 16
// EventType defines different kinds of inotfiy events.
//
// The way events are labelled appears somewhat arbitrary, but they must match
// Linux so that IN_EXCL_UNLINK behaves as it does in Linux.
type EventType uint8
// PathEvent and InodeEvent correspond to FSNOTIFY_EVENT_PATH and
// FSNOTIFY_EVENT_INODE in Linux.
const (
PathEvent EventType = iota
InodeEvent EventType = iota
)
// Inotify represents an inotify instance created by inotify_init(2) or
// inotify_init1(2). Inotify implements FileDescriptionImpl.
//
@@ -419,13 +432,22 @@ func (w *Watches) Remove(id uint64) {
}
// Notify queues a new event with all watches in this set.
func (w *Watches) Notify(name string, events, cookie uint32) {
func (w *Watches) Notify(name string, events, cookie uint32, et EventType) {
w.NotifyWithExclusions(name, events, cookie, et, false)
}
// NotifyWithExclusions queues a new event with watches in this set. Watches
// with IN_EXCL_UNLINK are skipped if the event is coming from a child that
// has been unlinked.
func (w *Watches) NotifyWithExclusions(name string, events, cookie uint32, et EventType, unlinked bool) {
// N.B. We don't defer the unlocks because Notify is in the hot path of
// all IO operations, and the defer costs too much for small IO
// operations.
w.mu.RLock()
for _, watch := range w.ws {
// TODO(gvisor.dev/issue/1479): Skip for IN_EXCL_UNLINK cases.
if unlinked && watch.ExcludeUnlinkedChildren() && et == PathEvent {
continue
}
watch.Notify(name, events, cookie)
}
w.mu.RUnlock()
@@ -434,7 +456,7 @@ func (w *Watches) Notify(name string, events, cookie uint32) {
// HandleDeletion is called when the watch target is destroyed to emit
// the appropriate events.
func (w *Watches) HandleDeletion() {
w.Notify("", linux.IN_DELETE_SELF, 0)
w.Notify("", linux.IN_DELETE_SELF, 0, InodeEvent)
// TODO(gvisor.dev/issue/1479): This doesn't work because maps are not copied
// by value. Ideally, we wouldn't have this circular locking so we can just
@@ -655,8 +677,8 @@ func InotifyEventFromStatMask(mask uint32) uint32 {
// InotifyRemoveChild sends the appriopriate notifications to the watch sets of
// the child being removed and its parent.
func InotifyRemoveChild(self, parent *Watches, name string) {
self.Notify("", linux.IN_ATTRIB, 0)
parent.Notify(name, linux.IN_DELETE, 0)
self.Notify("", linux.IN_ATTRIB, 0, InodeEvent)
parent.Notify(name, linux.IN_DELETE, 0, InodeEvent)
// TODO(gvisor.dev/issue/1479): implement IN_EXCL_UNLINK.
}
@@ -668,8 +690,8 @@ func InotifyRename(ctx context.Context, renamed, oldParent, newParent *Watches,
dirEv = linux.IN_ISDIR
}
cookie := uniqueid.InotifyCookie(ctx)
oldParent.Notify(oldName, dirEv|linux.IN_MOVED_FROM, cookie)
newParent.Notify(newName, dirEv|linux.IN_MOVED_TO, cookie)
oldParent.Notify(oldName, dirEv|linux.IN_MOVED_FROM, cookie, InodeEvent)
newParent.Notify(newName, dirEv|linux.IN_MOVED_TO, cookie, InodeEvent)
// Somewhat surprisingly, self move events do not have a cookie.
renamed.Notify("", linux.IN_MOVE_SELF, 0)
renamed.Notify("", linux.IN_MOVE_SELF, 0, InodeEvent)
}
pkg/sentry/vfs/vfs.go
+1 -1
View File
@@ -422,7 +422,7 @@ func (vfs *VirtualFilesystem) OpenAt(ctx context.Context, creds *auth.Credential
}
}
fd.Dentry().InotifyWithParent(linux.IN_OPEN, 0)
fd.Dentry().InotifyWithParent(linux.IN_OPEN, 0, PathEvent)
return fd, nil
}
if !rp.handleError(err) {
test/syscalls/linux/inotify.cc
+164
View File
@@ -1778,6 +1778,170 @@ TEST(Inotify, IncludeUnlinkedFile_NoRandomSave) {
}));
}
// Watches created with IN_EXCL_UNLINK will stop emitting events on fds for
// children that have already been unlinked.
//
// We need to disable S/R because there are filesystems where we cannot re-open
// fds to an unlinked file across S/R, e.g. gofer-backed filesytems.
TEST(Inotify, ExcludeUnlink_NoRandomSave) {
const DisableSave ds;
// TODO(gvisor.dev/issue/1624): This test fails on VFS1.
SKIP_IF(IsRunningWithVFS1());
const TempPath dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
const TempPath file =
ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileIn(dir.path()));
const FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDWR));
const FileDescriptor inotify_fd =
ASSERT_NO_ERRNO_AND_VALUE(InotifyInit1(IN_NONBLOCK));
const int wd = ASSERT_NO_ERRNO_AND_VALUE(InotifyAddWatch(
inotify_fd.get(), dir.path(), IN_ALL_EVENTS | IN_EXCL_UNLINK));
// Unlink the child, which should cause further operations on the open file
// descriptor to be ignored.
ASSERT_THAT(unlink(file.path().c_str()), SyscallSucceeds());
int val = 0;
ASSERT_THAT(write(fd.get(), &val, sizeof(val)), SyscallSucceeds());
ASSERT_THAT(read(fd.get(), &val, sizeof(val)), SyscallSucceeds());
const std::vector<Event> events =
ASSERT_NO_ERRNO_AND_VALUE(DrainEvents(inotify_fd.get()));
EXPECT_THAT(events, Are({Event(IN_DELETE, wd, Basename(file.path()))}));
}
// We need to disable S/R because there are filesystems where we cannot re-open
// fds to an unlinked file across S/R, e.g. gofer-backed filesytems.
TEST(Inotify, ExcludeUnlinkDirectory_NoRandomSave) {
const DisableSave ds;
const TempPath parent = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
TempPath dir =
ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDirIn(parent.path()));
std::string dirPath = dir.path();
const FileDescriptor inotify_fd =
ASSERT_NO_ERRNO_AND_VALUE(InotifyInit1(IN_NONBLOCK));
const FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(dirPath.c_str(), O_RDONLY | O_DIRECTORY));
const int wd = ASSERT_NO_ERRNO_AND_VALUE(InotifyAddWatch(
inotify_fd.get(), parent.path(), IN_ALL_EVENTS | IN_EXCL_UNLINK));
// Unlink the dir, and then close the open fd.
ASSERT_THAT(rmdir(dirPath.c_str()), SyscallSucceeds());
dir.reset();
const std::vector<Event> events =
ASSERT_NO_ERRNO_AND_VALUE(DrainEvents(inotify_fd.get()));
// No close event should appear.
ASSERT_THAT(events,
Are({Event(IN_DELETE | IN_ISDIR, wd, Basename(dirPath))}));
}
// If "dir/child" and "dir/child2" are links to the same file, and "dir/child"
// is unlinked, a watch on "dir" with IN_EXCL_UNLINK will exclude future events
// for fds on "dir/child" but not "dir/child2".
//
// We need to disable S/R because there are filesystems where we cannot re-open
// fds to an unlinked file across S/R, e.g. gofer-backed filesytems.
TEST(Inotify, ExcludeUnlinkMultipleChildren_NoRandomSave) {
const DisableSave ds;
// TODO(gvisor.dev/issue/1624): This test fails on VFS1.
SKIP_IF(IsRunningWithVFS1());
const TempPath dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
const TempPath file =
ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileIn(dir.path()));
std::string path1 = file.path();
std::string path2 = NewTempAbsPathInDir(dir.path());
const int rc = link(path1.c_str(), path2.c_str());
// NOTE(b/34861058): link(2) is only supported on tmpfs in the sandbox.
SKIP_IF(IsRunningOnGvisor() && rc != 0 &&
(errno == EPERM || errno == ENOENT));
ASSERT_THAT(rc, SyscallSucceeds());
const FileDescriptor fd1 =
ASSERT_NO_ERRNO_AND_VALUE(Open(path1.c_str(), O_RDWR));
const FileDescriptor fd2 =
ASSERT_NO_ERRNO_AND_VALUE(Open(path2.c_str(), O_RDWR));
const FileDescriptor inotify_fd =
ASSERT_NO_ERRNO_AND_VALUE(InotifyInit1(IN_NONBLOCK));
const int wd = ASSERT_NO_ERRNO_AND_VALUE(InotifyAddWatch(
inotify_fd.get(), dir.path(), IN_ALL_EVENTS | IN_EXCL_UNLINK));
// After unlinking path1, only events on the fd for path2 should be generated.
ASSERT_THAT(unlink(path1.c_str()), SyscallSucceeds());
ASSERT_THAT(write(fd1.get(), "x", 1), SyscallSucceeds());
ASSERT_THAT(write(fd2.get(), "x", 1), SyscallSucceeds());
const std::vector<Event> events =
ASSERT_NO_ERRNO_AND_VALUE(DrainEvents(inotify_fd.get()));
EXPECT_THAT(events, Are({
Event(IN_DELETE, wd, Basename(path1)),
Event(IN_MODIFY, wd, Basename(path2)),
}));
}
// On native Linux, actions of data type FSNOTIFY_EVENT_INODE are not affected
// by IN_EXCL_UNLINK (see
// fs/notify/inotify/inotify_fsnotify.c:inotify_handle_event). Inode-level
// events include changes to metadata and extended attributes.
//
// We need to disable S/R because there are filesystems where we cannot re-open
// fds to an unlinked file across S/R, e.g. gofer-backed filesytems.
TEST(Inotify, ExcludeUnlinkInodeEvents_NoRandomSave) {
const DisableSave ds;
const TempPath dir = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
const TempPath file =
ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFileIn(dir.path()));
const FileDescriptor fd =
ASSERT_NO_ERRNO_AND_VALUE(Open(file.path().c_str(), O_RDWR));
const FileDescriptor inotify_fd =
ASSERT_NO_ERRNO_AND_VALUE(InotifyInit1(IN_NONBLOCK));
const int wd = ASSERT_NO_ERRNO_AND_VALUE(InotifyAddWatch(
inotify_fd.get(), dir.path(), IN_ALL_EVENTS | IN_EXCL_UNLINK));
// NOTE(b/157163751): Create another link before unlinking. This is needed for
// the gofer filesystem in gVisor, where open fds will not work once the link
// count hits zero. In VFS2, we end up skipping the gofer test anyway, because
// hard links are not supported for gofer fs.
if (IsRunningOnGvisor()) {
std::string link_path = NewTempAbsPath();
const int rc = link(file.path().c_str(), link_path.c_str());
// NOTE(b/34861058): link(2) is only supported on tmpfs in the sandbox.
SKIP_IF(rc != 0 && (errno == EPERM || errno == ENOENT));
ASSERT_THAT(rc, SyscallSucceeds());
}
// Even after unlinking, inode-level operations will trigger events regardless
// of IN_EXCL_UNLINK.
ASSERT_THAT(unlink(file.path().c_str()), SyscallSucceeds());
// Perform various actions on fd.
ASSERT_THAT(ftruncate(fd.get(), 12345), SyscallSucceeds());
std::vector<Event> events =
ASSERT_NO_ERRNO_AND_VALUE(DrainEvents(inotify_fd.get()));
EXPECT_THAT(events, Are({
Event(IN_DELETE, wd, Basename(file.path())),
Event(IN_MODIFY, wd, Basename(file.path())),
}));
struct timeval times[2] = {{1, 0}, {2, 0}};
ASSERT_THAT(futimes(fd.get(), times), SyscallSucceeds());
events = ASSERT_NO_ERRNO_AND_VALUE(DrainEvents(inotify_fd.get()));
EXPECT_THAT(events, Are({Event(IN_ATTRIB, wd, Basename(file.path()))}));
// S/R is disabled on this entire test due to behavior with unlink; it must
// also be disabled after this point because of fchmod.
ASSERT_THAT(fchmod(fd.get(), 0777), SyscallSucceeds());
events = ASSERT_NO_ERRNO_AND_VALUE(DrainEvents(inotify_fd.get()));
EXPECT_THAT(events, Are({Event(IN_ATTRIB, wd, Basename(file.path()))}));
}
} // namespace
} // namespace testing
} // namespace gvisor