From f03996c5e9803934226e4b3a10827501cb936ab9 Mon Sep 17 00:00:00 2001 From: Jamie Liu Date: Thu, 16 Apr 2020 19:26:02 -0700 Subject: Implement pipe(2) and pipe2(2) for VFS2. Updates #1035 PiperOrigin-RevId: 306968644 --- pkg/sentry/syscalls/linux/sys_pipe.go | 14 +++-- pkg/sentry/syscalls/linux/vfs2/BUILD | 3 ++ pkg/sentry/syscalls/linux/vfs2/fd.go | 17 ++++++ .../syscalls/linux/vfs2/linux64_override_amd64.go | 4 +- pkg/sentry/syscalls/linux/vfs2/pipe.go | 63 ++++++++++++++++++++++ pkg/sentry/syscalls/linux/vfs2/read_write.go | 8 +-- 6 files changed, 99 insertions(+), 10 deletions(-) create mode 100644 pkg/sentry/syscalls/linux/vfs2/pipe.go (limited to 'pkg/sentry/syscalls/linux') diff --git a/pkg/sentry/syscalls/linux/sys_pipe.go b/pkg/sentry/syscalls/linux/sys_pipe.go index 798344042..43c510930 100644 --- a/pkg/sentry/syscalls/linux/sys_pipe.go +++ b/pkg/sentry/syscalls/linux/sys_pipe.go @@ -24,6 +24,8 @@ import ( "gvisor.dev/gvisor/pkg/usermem" ) +// LINT.IfChange + // pipe2 implements the actual system call with flags. func pipe2(t *kernel.Task, addr usermem.Addr, flags uint) (uintptr, error) { if flags&^(linux.O_NONBLOCK|linux.O_CLOEXEC) != 0 { @@ -45,10 +47,12 @@ func pipe2(t *kernel.Task, addr usermem.Addr, flags uint) (uintptr, error) { } if _, err := t.CopyOut(addr, fds); err != nil { - // The files are not closed in this case, the exact semantics - // of this error case are not well defined, but they could have - // already been observed by user space. - return 0, syserror.EFAULT + for _, fd := range fds { + if file, _ := t.FDTable().Remove(fd); file != nil { + file.DecRef() + } + } + return 0, err } return 0, nil } @@ -69,3 +73,5 @@ func Pipe2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall n, err := pipe2(t, addr, flags) return n, nil, err } + +// LINT.ThenChange(vfs2/pipe.go) diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD index b32abfe59..6ff2d84d2 100644 --- a/pkg/sentry/syscalls/linux/vfs2/BUILD +++ b/pkg/sentry/syscalls/linux/vfs2/BUILD @@ -18,6 +18,7 @@ go_library( "linux64_override_arm64.go", "mmap.go", "path.go", + "pipe.go", "poll.go", "read_write.go", "setstat.go", @@ -39,8 +40,10 @@ go_library( "//pkg/gohacks", "//pkg/sentry/arch", "//pkg/sentry/fsbridge", + "//pkg/sentry/fsimpl/pipefs", "//pkg/sentry/kernel", "//pkg/sentry/kernel/auth", + "//pkg/sentry/kernel/pipe", "//pkg/sentry/kernel/time", "//pkg/sentry/limits", "//pkg/sentry/loader", diff --git a/pkg/sentry/syscalls/linux/vfs2/fd.go b/pkg/sentry/syscalls/linux/vfs2/fd.go index 3afcea665..8181d80f4 100644 --- a/pkg/sentry/syscalls/linux/vfs2/fd.go +++ b/pkg/sentry/syscalls/linux/vfs2/fd.go @@ -18,6 +18,7 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/kernel/pipe" slinux "gvisor.dev/gvisor/pkg/sentry/syscalls/linux" "gvisor.dev/gvisor/pkg/syserror" ) @@ -140,6 +141,22 @@ func Fcntl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return uintptr(file.StatusFlags()), nil, nil case linux.F_SETFL: return 0, nil, file.SetStatusFlags(t, t.Credentials(), args[2].Uint()) + case linux.F_SETPIPE_SZ: + pipefile, ok := file.Impl().(*pipe.VFSPipeFD) + if !ok { + return 0, nil, syserror.EBADF + } + n, err := pipefile.SetPipeSize(int64(args[2].Int())) + if err != nil { + return 0, nil, err + } + return uintptr(n), nil, nil + case linux.F_GETPIPE_SZ: + pipefile, ok := file.Impl().(*pipe.VFSPipeFD) + if !ok { + return 0, nil, syserror.EBADF + } + return uintptr(pipefile.PipeSize()), nil, nil default: // TODO(gvisor.dev/issue/1623): Everything else is not yet supported. return 0, nil, syserror.EINVAL diff --git a/pkg/sentry/syscalls/linux/vfs2/linux64_override_amd64.go b/pkg/sentry/syscalls/linux/vfs2/linux64_override_amd64.go index 645e0bcb8..21eb98444 100644 --- a/pkg/sentry/syscalls/linux/vfs2/linux64_override_amd64.go +++ b/pkg/sentry/syscalls/linux/vfs2/linux64_override_amd64.go @@ -39,7 +39,7 @@ func Override(table map[uintptr]kernel.Syscall) { table[19] = syscalls.Supported("readv", Readv) table[20] = syscalls.Supported("writev", Writev) table[21] = syscalls.Supported("access", Access) - delete(table, 22) // pipe + table[22] = syscalls.Supported("pipe", Pipe) table[23] = syscalls.Supported("select", Select) table[32] = syscalls.Supported("dup", Dup) table[33] = syscalls.Supported("dup2", Dup2) @@ -151,7 +151,7 @@ func Override(table map[uintptr]kernel.Syscall) { delete(table, 290) // eventfd2 table[291] = syscalls.Supported("epoll_create1", EpollCreate1) table[292] = syscalls.Supported("dup3", Dup3) - delete(table, 293) // pipe2 + table[293] = syscalls.Supported("pipe2", Pipe2) delete(table, 294) // inotify_init1 table[295] = syscalls.Supported("preadv", Preadv) table[296] = syscalls.Supported("pwritev", Pwritev) diff --git a/pkg/sentry/syscalls/linux/vfs2/pipe.go b/pkg/sentry/syscalls/linux/vfs2/pipe.go new file mode 100644 index 000000000..4a01e4209 --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/pipe.go @@ -0,0 +1,63 @@ +// 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/fsimpl/pipefs" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" +) + +// Pipe implements Linux syscall pipe(2). +func Pipe(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + addr := args[0].Pointer() + return 0, nil, pipe2(t, addr, 0) +} + +// Pipe2 implements Linux syscall pipe2(2). +func Pipe2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + addr := args[0].Pointer() + flags := args[1].Int() + return 0, nil, pipe2(t, addr, flags) +} + +func pipe2(t *kernel.Task, addr usermem.Addr, flags int32) error { + if flags&^(linux.O_NONBLOCK|linux.O_CLOEXEC) != 0 { + return syserror.EINVAL + } + r, w := pipefs.NewConnectedPipeFDs(t, t.Kernel().PipeMount(), uint32(flags&linux.O_NONBLOCK)) + defer r.DecRef() + defer w.DecRef() + + fds, err := t.NewFDsVFS2(0, []*vfs.FileDescription{r, w}, kernel.FDFlags{ + CloseOnExec: flags&linux.O_CLOEXEC != 0, + }) + if err != nil { + return err + } + if _, err := t.CopyOut(addr, fds); err != nil { + for _, fd := range fds { + if _, file := t.FDTable().Remove(fd); file != nil { + file.DecRef() + } + } + return err + } + return nil +} diff --git a/pkg/sentry/syscalls/linux/vfs2/read_write.go b/pkg/sentry/syscalls/linux/vfs2/read_write.go index 898b190fd..6c6998f45 100644 --- a/pkg/sentry/syscalls/linux/vfs2/read_write.go +++ b/pkg/sentry/syscalls/linux/vfs2/read_write.go @@ -103,7 +103,7 @@ func read(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, opt // Issue the request and break out if it completes with anything other than // "would block". - n, err := file.Read(t, dst, opts) + n, err = file.Read(t, dst, opts) total += n if err != syserror.ErrWouldBlock { break @@ -248,7 +248,7 @@ func pread(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, of // Issue the request and break out if it completes with anything other than // "would block". - n, err := file.PRead(t, dst, offset+total, opts) + n, err = file.PRead(t, dst, offset+total, opts) total += n if err != syserror.ErrWouldBlock { break @@ -335,7 +335,7 @@ func write(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, op // Issue the request and break out if it completes with anything other than // "would block". - n, err := file.Write(t, src, opts) + n, err = file.Write(t, src, opts) total += n if err != syserror.ErrWouldBlock { break @@ -480,7 +480,7 @@ func pwrite(t *kernel.Task, file *vfs.FileDescription, src usermem.IOSequence, o // Issue the request and break out if it completes with anything other than // "would block". - n, err := file.PWrite(t, src, offset+total, opts) + n, err = file.PWrite(t, src, offset+total, opts) total += n if err != syserror.ErrWouldBlock { break -- cgit v1.2.3