diff options
Diffstat (limited to 'pkg/sentry/memmap/memmap.go')
| -rw-r--r-- | pkg/sentry/memmap/memmap.go | 60 |
1 files changed, 53 insertions, 7 deletions
diff --git a/pkg/sentry/memmap/memmap.go b/pkg/sentry/memmap/memmap.go index c6db9fc8f..c188f6c29 100644 --- a/pkg/sentry/memmap/memmap.go +++ b/pkg/sentry/memmap/memmap.go @@ -19,12 +19,12 @@ import ( "fmt" "gvisor.dev/gvisor/pkg/context" - "gvisor.dev/gvisor/pkg/sentry/platform" + "gvisor.dev/gvisor/pkg/safemem" "gvisor.dev/gvisor/pkg/usermem" ) // Mappable represents a memory-mappable object, a mutable mapping from uint64 -// offsets to (platform.File, uint64 File offset) pairs. +// offsets to (File, uint64 File offset) pairs. // // See mm/mm.go for Mappable's place in the lock order. // @@ -74,7 +74,7 @@ type Mappable interface { // Translations are valid until invalidated by a callback to // MappingSpace.Invalidate or until the caller removes its mapping of the // translated range. Mappable implementations must ensure that at least one - // reference is held on all pages in a platform.File that may be the result + // reference is held on all pages in a File that may be the result // of a valid Translation. // // Preconditions: required.Length() > 0. optional.IsSupersetOf(required). @@ -100,7 +100,7 @@ type Translation struct { Source MappableRange // File is the mapped file. - File platform.File + File File // Offset is the offset into File at which this Translation begins. Offset uint64 @@ -110,9 +110,9 @@ type Translation struct { Perms usermem.AccessType } -// FileRange returns the platform.FileRange represented by t. -func (t Translation) FileRange() platform.FileRange { - return platform.FileRange{t.Offset, t.Offset + t.Source.Length()} +// FileRange returns the FileRange represented by t. +func (t Translation) FileRange() FileRange { + return FileRange{t.Offset, t.Offset + t.Source.Length()} } // CheckTranslateResult returns an error if (ts, terr) does not satisfy all @@ -361,3 +361,49 @@ type MMapOpts struct { // TODO(jamieliu): Replace entirely with MappingIdentity? Hint string } + +// File represents a host file that may be mapped into an platform.AddressSpace. +type File interface { + // All pages in a File are reference-counted. + + // IncRef increments the reference count on all pages in fr. + // + // Preconditions: fr.Start and fr.End must be page-aligned. fr.Length() > + // 0. At least one reference must be held on all pages in fr. (The File + // interface does not provide a way to acquire an initial reference; + // implementors may define mechanisms for doing so.) + IncRef(fr FileRange) + + // DecRef decrements the reference count on all pages in fr. + // + // Preconditions: fr.Start and fr.End must be page-aligned. fr.Length() > + // 0. At least one reference must be held on all pages in fr. + DecRef(fr FileRange) + + // MapInternal returns a mapping of the given file offsets in the invoking + // process' address space for reading and writing. + // + // Note that fr.Start and fr.End need not be page-aligned. + // + // Preconditions: fr.Length() > 0. At least one reference must be held on + // all pages in fr. + // + // Postconditions: The returned mapping is valid as long as at least one + // reference is held on the mapped pages. + MapInternal(fr FileRange, at usermem.AccessType) (safemem.BlockSeq, error) + + // FD returns the file descriptor represented by the File. + // + // The only permitted operation on the returned file descriptor is to map + // pages from it consistent with the requirements of AddressSpace.MapFile. + FD() int +} + +// FileRange represents a range of uint64 offsets into a File. +// +// type FileRange <generated using go_generics> + +// String implements fmt.Stringer.String. +func (fr FileRange) String() string { + return fmt.Sprintf("[%#x, %#x)", fr.Start, fr.End) +} |