diff options
Diffstat (limited to 'pkg/sentry/syscalls/linux/vfs2')
-rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/BUILD | 24 | ||||
-rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/linux64.go | 16 | ||||
-rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/linux64_override_amd64.go | 25 | ||||
-rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/linux64_override_arm64.go | 25 | ||||
-rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/sys_read.go | 95 |
5 files changed, 185 insertions, 0 deletions
diff --git a/pkg/sentry/syscalls/linux/vfs2/BUILD b/pkg/sentry/syscalls/linux/vfs2/BUILD new file mode 100644 index 000000000..6b8a00b6e --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/BUILD @@ -0,0 +1,24 @@ +load("//tools:defs.bzl", "go_library") + +package(licenses = ["notice"]) + +go_library( + name = "vfs2", + srcs = [ + "linux64.go", + "linux64_override_amd64.go", + "linux64_override_arm64.go", + "sys_read.go", + ], + visibility = ["//:sandbox"], + deps = [ + "//pkg/sentry/arch", + "//pkg/sentry/kernel", + "//pkg/sentry/syscalls", + "//pkg/sentry/syscalls/linux", + "//pkg/sentry/vfs", + "//pkg/syserror", + "//pkg/usermem", + "//pkg/waiter", + ], +) diff --git a/pkg/sentry/syscalls/linux/vfs2/linux64.go b/pkg/sentry/syscalls/linux/vfs2/linux64.go new file mode 100644 index 000000000..19ee36081 --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/linux64.go @@ -0,0 +1,16 @@ +// 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 provides syscall implementations that use VFS2. +package vfs2 diff --git a/pkg/sentry/syscalls/linux/vfs2/linux64_override_amd64.go b/pkg/sentry/syscalls/linux/vfs2/linux64_override_amd64.go new file mode 100644 index 000000000..c134714ee --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/linux64_override_amd64.go @@ -0,0 +1,25 @@ +// 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/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/syscalls" +) + +// Override syscall table to add syscalls implementations from this package. +func Override(table map[uintptr]kernel.Syscall) { + table[0] = syscalls.Supported("read", Read) +} diff --git a/pkg/sentry/syscalls/linux/vfs2/linux64_override_arm64.go b/pkg/sentry/syscalls/linux/vfs2/linux64_override_arm64.go new file mode 100644 index 000000000..6af5c400f --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/linux64_override_arm64.go @@ -0,0 +1,25 @@ +// 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/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/syscalls" +) + +// Override syscall table to add syscalls implementations from this package. +func Override(table map[uintptr]kernel.Syscall) { + table[63] = syscalls.Supported("read", Read) +} diff --git a/pkg/sentry/syscalls/linux/vfs2/sys_read.go b/pkg/sentry/syscalls/linux/vfs2/sys_read.go new file mode 100644 index 000000000..b9fb58464 --- /dev/null +++ b/pkg/sentry/syscalls/linux/vfs2/sys_read.go @@ -0,0 +1,95 @@ +// 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/sentry/arch" + "gvisor.dev/gvisor/pkg/sentry/kernel" + "gvisor.dev/gvisor/pkg/sentry/syscalls/linux" + "gvisor.dev/gvisor/pkg/sentry/vfs" + "gvisor.dev/gvisor/pkg/syserror" + "gvisor.dev/gvisor/pkg/usermem" + "gvisor.dev/gvisor/pkg/waiter" +) + +// Read implements linux syscall read(2). Note that we try to get a buffer that +// is exactly the size requested because some applications like qemu expect +// they can do large reads all at once. Bug for bug. Same for other read +// calls below. +func Read(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + addr := args[1].Pointer() + size := args[2].SizeT() + + file := t.GetFileVFS2(fd) + if file == nil { + return 0, nil, syserror.EBADF + } + defer file.DecRef() + + // Check that the file is readable. + if !file.IsReadable() { + return 0, nil, syserror.EBADF + } + + // Check that the size is legitimate. + si := int(size) + if si < 0 { + return 0, nil, syserror.EINVAL + } + + // Get the destination of the read. + dst, err := t.SingleIOSequence(addr, si, usermem.IOOpts{ + AddressSpaceActive: true, + }) + if err != nil { + return 0, nil, err + } + + n, err := read(t, file, dst, vfs.ReadOptions{}) + t.IOUsage().AccountReadSyscall(n) + return uintptr(n), nil, linux.HandleIOErrorVFS2(t, n != 0, err, kernel.ERESTARTSYS, "read", file) +} + +func read(t *kernel.Task, file *vfs.FileDescription, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) { + n, err := file.Read(t, dst, opts) + if err != syserror.ErrWouldBlock { + return n, err + } + + // Register for notifications. + _, ch := waiter.NewChannelEntry(nil) + // file.EventRegister(&w, EventMaskRead) + + total := n + for { + // Shorten dst to reflect bytes previously read. + dst = dst.DropFirst(int(n)) + + // Issue the request and break out if it completes with anything other than + // "would block". + n, err := file.Read(t, dst, opts) + total += n + if err != syserror.ErrWouldBlock { + break + } + if err := t.Block(ch); err != nil { + break + } + } + //file.EventUnregister(&w) + + return total, err +} |