diff options
Diffstat (limited to 'pkg/sentry/syscalls/linux/vfs2')
-rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/BUILD | 2 | ||||
-rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/lock.go | 64 | ||||
-rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/vfs2.go | 2 |
3 files changed, 67 insertions, 1 deletions
diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD index c0d005247..9f93f4354 100644 --- a/pkg/sentry/syscalls/linux/vfs2/BUILD +++ b/pkg/sentry/syscalls/linux/vfs2/BUILD @@ -14,6 +14,7 @@ go_library( "getdents.go", "inotify.go", "ioctl.go", + "lock.go", "memfd.go", "mmap.go", "mount.go", @@ -42,6 +43,7 @@ go_library( "//pkg/fspath", "//pkg/gohacks", "//pkg/sentry/arch", + "//pkg/sentry/fs/lock", "//pkg/sentry/fsbridge", "//pkg/sentry/fsimpl/eventfd", "//pkg/sentry/fsimpl/pipefs", diff --git a/pkg/sentry/syscalls/linux/vfs2/lock.go b/pkg/sentry/syscalls/linux/vfs2/lock.go new file mode 100644 index 000000000..bf19028c4 --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/lock.go @@ -0,0 +1,64 @@ +// Copyright 2020 The gVisor Authors. +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package vfs2 + +import ( + "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/fs/lock" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/syserror" +) + +// Flock implements linux syscall flock(2). +func Flock(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + operation := args[1].Int() + + file := t.GetFileVFS2(fd) + if file == nil { + // flock(2): EBADF fd is not an open file descriptor. + return 0, nil, syserror.EBADF + } + defer file.DecRef() + + nonblocking := operation&linux.LOCK_NB != 0 + operation &^= linux.LOCK_NB + + var blocker lock.Blocker + if !nonblocking { + blocker = t + } + + switch operation { + case linux.LOCK_EX: + if err := file.LockBSD(t, lock.WriteLock, blocker); err != nil { + return 0, nil, err + } + case linux.LOCK_SH: + if err := file.LockBSD(t, lock.ReadLock, blocker); err != nil { + return 0, nil, err + } + case linux.LOCK_UN: + if err := file.UnlockBSD(t); err != nil { + return 0, nil, err + } + default: + // flock(2): EINVAL operation is invalid. + return 0, nil, syserror.EINVAL + } + + return 0, nil, nil +} diff --git a/pkg/sentry/syscalls/linux/vfs2/vfs2.go b/pkg/sentry/syscalls/linux/vfs2/vfs2.go index 7b6e7571a..954c82f97 100644 --- a/pkg/sentry/syscalls/linux/vfs2/vfs2.go +++ b/pkg/sentry/syscalls/linux/vfs2/vfs2.go @@ -62,7 +62,7 @@ func Override() { s.Table[55] = syscalls.Supported("getsockopt", GetSockOpt) s.Table[59] = syscalls.Supported("execve", Execve) s.Table[72] = syscalls.Supported("fcntl", Fcntl) - delete(s.Table, 73) // flock + s.Table[73] = syscalls.Supported("fcntl", Flock) s.Table[74] = syscalls.Supported("fsync", Fsync) s.Table[75] = syscalls.Supported("fdatasync", Fdatasync) s.Table[76] = syscalls.Supported("truncate", Truncate) |