diff options
| author | Jamie Liu <jamieliu@google.com> | 2020-09-18 13:23:41 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2020-09-18 13:25:35 -0700 |
| commit | ca4ecf481d617edfae22a5735a657d60186392e1 (patch) | |
| tree | 539dc1cef2df460610f96e488efc672c92fc7b1a /pkg/sentry/syscalls/linux/sys_mmap.go | |
| parent | f911b43f05f88807a1e36adc6ab3b7c8cf8ec2ee (diff) | |
Use a tmpfs file for shared anonymous and /dev/zero mmap on VFS2.
This is more consistent with Linux (see comment on MM.NewSharedAnonMappable()).
We don't do the same thing on VFS1 for reasons documented by the updated
comment.
PiperOrigin-RevId: 332514849
Diffstat (limited to 'pkg/sentry/syscalls/linux/sys_mmap.go')
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_mmap.go | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_mmap.go b/pkg/sentry/syscalls/linux/sys_mmap.go index 8ab062bca..cd8dfdfa4 100644 --- a/pkg/sentry/syscalls/linux/sys_mmap.go +++ b/pkg/sentry/syscalls/linux/sys_mmap.go @@ -100,6 +100,15 @@ func Mmap(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallC if err := file.ConfigureMMap(t, &opts); err != nil { return 0, nil, err } + } else if shared { + // Back shared anonymous mappings with a special mappable. + opts.Offset = 0 + m, err := mm.NewSharedAnonMappable(opts.Length, t.Kernel()) + if err != nil { + return 0, nil, err + } + opts.MappingIdentity = m // transfers ownership of m to opts + opts.Mappable = m } rv, err := t.MemoryManager().MMap(t, opts) |