diff options
| -rw-r--r-- | pkg/sentry/fsimpl/proc/task_fds.go | 13 | ||||
| -rw-r--r-- | test/syscalls/linux/proc.cc | 24 |
2 files changed, 33 insertions, 4 deletions
diff --git a/pkg/sentry/fsimpl/proc/task_fds.go b/pkg/sentry/fsimpl/proc/task_fds.go index 3f0d78461..94ec2ff69 100644 --- a/pkg/sentry/fsimpl/proc/task_fds.go +++ b/pkg/sentry/fsimpl/proc/task_fds.go @@ -86,14 +86,19 @@ func (i *fdDir) IterDirents(ctx context.Context, cb vfs.IterDirentsCallback, off Name: strconv.FormatUint(uint64(fd), 10), Type: typ, Ino: i.fs.NextIno(), - NextOff: offset + 1, + NextOff: int64(fd) + 3, } if err := cb.Handle(dirent); err != nil { - return offset, err + // Getdents should iterate correctly despite mutation + // of fds, so we return the next fd to serialize plus + // 2 (which accounts for the "." and ".." tracked by + // kernfs) as the offset. + return int64(fd) + 2, err } - offset++ } - return offset, nil + // We serialized them all. Next offset should be higher than last + // serialized fd. + return int64(fds[len(fds)-1]) + 3, nil } // fdDirInode represents the inode for /proc/[pid]/fd directory. diff --git a/test/syscalls/linux/proc.cc b/test/syscalls/linux/proc.cc index b73189e55..f3f80a12a 100644 --- a/test/syscalls/linux/proc.cc +++ b/test/syscalls/linux/proc.cc @@ -694,6 +694,30 @@ TEST(ProcSelfFd, OpenFd) { ASSERT_THAT(close(pipe_fds[1]), SyscallSucceeds()); } +static void CheckFdDirGetdentsDuplicates(const std::string& path) { + const FileDescriptor fd = + ASSERT_NO_ERRNO_AND_VALUE(Open(path.c_str(), O_RDONLY | O_DIRECTORY)); + // Open a FD whose value is supposed to be much larger than + // the number of FDs opened by current process. + auto newfd = fcntl(fd.get(), F_DUPFD, 1024); + EXPECT_GE(newfd, 1024); + auto fd_closer = Cleanup([newfd]() { close(newfd); }); + auto fd_files = ASSERT_NO_ERRNO_AND_VALUE(ListDir(path.c_str(), false)); + std::unordered_set<std::string> fd_files_dedup(fd_files.begin(), + fd_files.end()); + EXPECT_EQ(fd_files.size(), fd_files_dedup.size()); +} + +// This is a regression test for gvisor.dev/issues/3894 +TEST(ProcSelfFd, GetdentsDuplicates) { + CheckFdDirGetdentsDuplicates("/proc/self/fd"); +} + +// This is a regression test for gvisor.dev/issues/3894 +TEST(ProcSelfFdInfo, GetdentsDuplicates) { + CheckFdDirGetdentsDuplicates("/proc/self/fdinfo"); +} + TEST(ProcSelfFdInfo, CorrectFds) { // Make sure there is at least one open file. auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile()); |