diff options
Diffstat (limited to 'pkg/sentry/fs/fsutil')
| -rw-r--r-- | pkg/sentry/fs/fsutil/inode_cached.go | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/pkg/sentry/fs/fsutil/inode_cached.go b/pkg/sentry/fs/fsutil/inode_cached.go index 6ca51ab0d..b690cfe93 100644 --- a/pkg/sentry/fs/fsutil/inode_cached.go +++ b/pkg/sentry/fs/fsutil/inode_cached.go @@ -138,8 +138,15 @@ type CachedFileObject interface { // Sync instructs the remote filesystem to sync the file to stable storage. Sync(ctx context.Context) error - // FD returns a host file descriptor. Return value must be -1 or not -1 - // for the lifetime of the CachedFileObject. + // FD returns a host file descriptor. If it is possible for + // CachingInodeOperations.AddMapping to have ever been called with writable + // = true, the FD must have been opened O_RDWR; otherwise, it may have been + // opened O_RDONLY or O_RDWR. (mmap unconditionally requires that mapped + // files are readable.) If no host file descriptor is available, FD returns + // a negative number. + // + // For any given CachedFileObject, if FD() ever succeeds (returns a + // non-negative number), it must always succeed. // // FD is called iff the file has been memory mapped. This implies that // the file was opened (see fs.InodeOperations.GetFile). |