summaryrefslogtreecommitdiffhomepage
diff options
context:
space:
mode:
Diffstat
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/splice.go321
-rw-r--r--pkg/sentry/syscalls/linux/vfs2/vfs2.go2
-rw-r--r--test/syscalls/BUILD2
3 files changed, 261 insertions, 64 deletions
diff --git a/pkg/sentry/syscalls/linux/vfs2/splice.go b/pkg/sentry/syscalls/linux/vfs2/splice.go
index 945a364a7..63ab11f8c 100644
--- a/pkg/sentry/syscalls/linux/vfs2/splice.go
+++ b/pkg/sentry/syscalls/linux/vfs2/splice.go
@@ -15,12 +15,15 @@
package vfs2
import (
+ "io"
+
"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"
"gvisor.dev/gvisor/pkg/sentry/vfs"
"gvisor.dev/gvisor/pkg/syserror"
+ "gvisor.dev/gvisor/pkg/usermem"
"gvisor.dev/gvisor/pkg/waiter"
)
@@ -110,16 +113,20 @@ func Splice(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal
// Move data.
var (
- n int64
- err error
- inCh chan struct{}
- outCh chan struct{}
+ n int64
+ err error
)
+ dw := dualWaiter{
+ inFile: inFile,
+ outFile: outFile,
+ }
+ defer dw.destroy()
for {
// If both input and output are pipes, delegate to the pipe
- // implementation. Otherwise, exactly one end is a pipe, which we
- // ensure is consistently ordered after the non-pipe FD's locks by
- // passing the pipe FD as usermem.IO to the non-pipe end.
+ // implementation. Otherwise, exactly one end is a pipe, which
+ // we ensure is consistently ordered after the non-pipe FD's
+ // locks by passing the pipe FD as usermem.IO to the non-pipe
+ // end.
switch {
case inIsPipe && outIsPipe:
n, err = pipe.Splice(t, outPipeFD, inPipeFD, count)
@@ -137,38 +144,15 @@ func Splice(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal
} else {
n, err = inFile.Read(t, outPipeFD.IOSequence(count), vfs.ReadOptions{})
}
+ default:
+ panic("not possible")
}
+
if n != 0 || err != syserror.ErrWouldBlock || nonBlock {
break
}
-
- // Note that the blocking behavior here is a bit different than the
- // normal pattern. Because we need to have both data to read and data
- // to write simultaneously, we actually explicitly block on both of
- // these cases in turn before returning to the splice operation.
- if inFile.Readiness(eventMaskRead)&eventMaskRead == 0 {
- if inCh == nil {
- inCh = make(chan struct{}, 1)
- inW, _ := waiter.NewChannelEntry(inCh)
- inFile.EventRegister(&inW, eventMaskRead)
- defer inFile.EventUnregister(&inW)
- continue // Need to refresh readiness.
- }
- if err = t.Block(inCh); err != nil {
- break
- }
- }
- if outFile.Readiness(eventMaskWrite)&eventMaskWrite == 0 {
- if outCh == nil {
- outCh = make(chan struct{}, 1)
- outW, _ := waiter.NewChannelEntry(outCh)
- outFile.EventRegister(&outW, eventMaskWrite)
- defer outFile.EventUnregister(&outW)
- continue // Need to refresh readiness.
- }
- if err = t.Block(outCh); err != nil {
- break
- }
+ if err = dw.waitForBoth(t); err != nil {
+ break
}
}
@@ -247,45 +231,256 @@ func Tee(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallCo
// Copy data.
var (
- inCh chan struct{}
- outCh chan struct{}
+ n int64
+ err error
)
+ dw := dualWaiter{
+ inFile: inFile,
+ outFile: outFile,
+ }
+ defer dw.destroy()
for {
- n, err := pipe.Tee(t, outPipeFD, inPipeFD, count)
- if n != 0 {
- return uintptr(n), nil, nil
+ n, err = pipe.Tee(t, outPipeFD, inPipeFD, count)
+ if n != 0 || err != syserror.ErrWouldBlock || nonBlock {
+ break
+ }
+ if err = dw.waitForBoth(t); err != nil {
+ break
+ }
+ }
+ if n == 0 {
+ return 0, nil, err
+ }
+ outFile.Dentry().InotifyWithParent(linux.IN_MODIFY, 0, vfs.PathEvent)
+ return uintptr(n), nil, nil
+}
+
+// Sendfile implements linux system call sendfile(2).
+func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ outFD := args[0].Int()
+ inFD := args[1].Int()
+ offsetAddr := args[2].Pointer()
+ count := int64(args[3].SizeT())
+
+ inFile := t.GetFileVFS2(inFD)
+ if inFile == nil {
+ return 0, nil, syserror.EBADF
+ }
+ defer inFile.DecRef()
+ if !inFile.IsReadable() {
+ return 0, nil, syserror.EBADF
+ }
+
+ outFile := t.GetFileVFS2(outFD)
+ if outFile == nil {
+ return 0, nil, syserror.EBADF
+ }
+ defer outFile.DecRef()
+ if !outFile.IsWritable() {
+ return 0, nil, syserror.EBADF
+ }
+
+ // Verify that the outFile Append flag is not set.
+ if outFile.StatusFlags()&linux.O_APPEND != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+
+ // Verify that inFile is a regular file or block device. This is a
+ // requirement; the same check appears in Linux
+ // (fs/splice.c:splice_direct_to_actor).
+ if stat, err := inFile.Stat(t, vfs.StatOptions{Mask: linux.STATX_TYPE}); err != nil {
+ return 0, nil, err
+ } else if stat.Mask&linux.STATX_TYPE == 0 ||
+ (stat.Mode&linux.S_IFMT != linux.S_IFREG && stat.Mode&linux.S_IFMT != linux.S_IFBLK) {
+ return 0, nil, syserror.EINVAL
+ }
+
+ // Copy offset if it exists.
+ offset := int64(-1)
+ if offsetAddr != 0 {
+ if inFile.Options().DenyPRead {
+ return 0, nil, syserror.ESPIPE
}
- if err != syserror.ErrWouldBlock || nonBlock {
+ if _, err := t.CopyIn(offsetAddr, &offset); err != nil {
return 0, nil, err
}
+ if offset < 0 {
+ return 0, nil, syserror.EINVAL
+ }
+ if offset+count < 0 {
+ return 0, nil, syserror.EINVAL
+ }
+ }
+
+ // Validate count. This must come after offset checks.
+ if count < 0 {
+ return 0, nil, syserror.EINVAL
+ }
+ if count == 0 {
+ return 0, nil, nil
+ }
+ if count > int64(kernel.MAX_RW_COUNT) {
+ count = int64(kernel.MAX_RW_COUNT)
+ }
- // Note that the blocking behavior here is a bit different than the
- // normal pattern. Because we need to have both data to read and data
- // to write simultaneously, we actually explicitly block on both of
- // these cases in turn before returning to the tee operation.
- if inFile.Readiness(eventMaskRead)&eventMaskRead == 0 {
- if inCh == nil {
- inCh = make(chan struct{}, 1)
- inW, _ := waiter.NewChannelEntry(inCh)
- inFile.EventRegister(&inW, eventMaskRead)
- defer inFile.EventUnregister(&inW)
- continue // Need to refresh readiness.
+ // Copy data.
+ var (
+ n int64
+ err error
+ )
+ dw := dualWaiter{
+ inFile: inFile,
+ outFile: outFile,
+ }
+ defer dw.destroy()
+ outPipeFD, outIsPipe := outFile.Impl().(*pipe.VFSPipeFD)
+ // Reading from input file should never block, since it is regular or
+ // block device. We only need to check if writing to the output file
+ // can block.
+ nonBlock := outFile.StatusFlags()&linux.O_NONBLOCK != 0
+ if outIsPipe {
+ for n < count {
+ var spliceN int64
+ if offset != -1 {
+ spliceN, err = inFile.PRead(t, outPipeFD.IOSequence(count), offset, vfs.ReadOptions{})
+ offset += spliceN
+ } else {
+ spliceN, err = inFile.Read(t, outPipeFD.IOSequence(count), vfs.ReadOptions{})
}
- if err := t.Block(inCh); err != nil {
- return 0, nil, err
+ n += spliceN
+ if err == syserror.ErrWouldBlock && !nonBlock {
+ err = dw.waitForBoth(t)
+ }
+ if err != nil {
+ break
}
}
- if outFile.Readiness(eventMaskWrite)&eventMaskWrite == 0 {
- if outCh == nil {
- outCh = make(chan struct{}, 1)
- outW, _ := waiter.NewChannelEntry(outCh)
- outFile.EventRegister(&outW, eventMaskWrite)
- defer outFile.EventUnregister(&outW)
- continue // Need to refresh readiness.
+ } else {
+ // Read inFile to buffer, then write the contents to outFile.
+ buf := make([]byte, count)
+ for n < count {
+ var readN int64
+ if offset != -1 {
+ readN, err = inFile.PRead(t, usermem.BytesIOSequence(buf), offset, vfs.ReadOptions{})
+ offset += readN
+ } else {
+ readN, err = inFile.Read(t, usermem.BytesIOSequence(buf), vfs.ReadOptions{})
+ }
+ if readN == 0 && err == io.EOF {
+ // We reached the end of the file. Eat the
+ // error and exit the loop.
+ err = nil
+ break
}
- if err := t.Block(outCh); err != nil {
- return 0, nil, err
+ n += readN
+ if err != nil {
+ break
+ }
+
+ // Write all of the bytes that we read. This may need
+ // multiple write calls to complete.
+ wbuf := buf[:n]
+ for len(wbuf) > 0 {
+ var writeN int64
+ writeN, err = outFile.Write(t, usermem.BytesIOSequence(wbuf), vfs.WriteOptions{})
+ wbuf = wbuf[writeN:]
+ if err == syserror.ErrWouldBlock && !nonBlock {
+ err = dw.waitForOut(t)
+ }
+ if err != nil {
+ // We didn't complete the write. Only
+ // report the bytes that were actually
+ // written, and rewind the offset.
+ notWritten := int64(len(wbuf))
+ n -= notWritten
+ if offset != -1 {
+ offset -= notWritten
+ }
+ break
+ }
+ }
+ if err == syserror.ErrWouldBlock && !nonBlock {
+ err = dw.waitForBoth(t)
}
+ if err != nil {
+ break
+ }
+ }
+ }
+
+ if offsetAddr != 0 {
+ // Copy out the new offset.
+ if _, err := t.CopyOut(offsetAddr, offset); err != nil {
+ return 0, nil, err
+ }
+ }
+
+ if n == 0 {
+ return 0, nil, err
+ }
+
+ inFile.Dentry().InotifyWithParent(linux.IN_ACCESS, 0, vfs.PathEvent)
+ outFile.Dentry().InotifyWithParent(linux.IN_MODIFY, 0, vfs.PathEvent)
+ return uintptr(n), nil, nil
+}
+
+// dualWaiter is used to wait on one or both vfs.FileDescriptions. It is not
+// thread-safe, and does not take a reference on the vfs.FileDescriptions.
+//
+// Users must call destroy() when finished.
+type dualWaiter struct {
+ inFile *vfs.FileDescription
+ outFile *vfs.FileDescription
+
+ inW waiter.Entry
+ inCh chan struct{}
+ outW waiter.Entry
+ outCh chan struct{}
+}
+
+// waitForBoth waits for both dw.inFile and dw.outFile to be ready.
+func (dw *dualWaiter) waitForBoth(t *kernel.Task) error {
+ if dw.inFile.Readiness(eventMaskRead)&eventMaskRead == 0 {
+ if dw.inCh == nil {
+ dw.inW, dw.inCh = waiter.NewChannelEntry(nil)
+ dw.inFile.EventRegister(&dw.inW, eventMaskRead)
+ // We might be ready now. Try again before blocking.
+ return nil
+ }
+ if err := t.Block(dw.inCh); err != nil {
+ return err
+ }
+ }
+ return dw.waitForOut(t)
+}
+
+// waitForOut waits for dw.outfile to be read.
+func (dw *dualWaiter) waitForOut(t *kernel.Task) error {
+ if dw.outFile.Readiness(eventMaskWrite)&eventMaskWrite == 0 {
+ if dw.outCh == nil {
+ dw.outW, dw.outCh = waiter.NewChannelEntry(nil)
+ dw.outFile.EventRegister(&dw.outW, eventMaskWrite)
+ // We might be ready now. Try again before blocking.
+ return nil
}
+ if err := t.Block(dw.outCh); err != nil {
+ return err
+ }
+ }
+ return nil
+}
+
+// destroy cleans up resources help by dw. No more calls to wait* can occur
+// after destroy is called.
+func (dw *dualWaiter) destroy() {
+ if dw.inCh != nil {
+ dw.inFile.EventUnregister(&dw.inW)
+ dw.inCh = nil
+ }
+ if dw.outCh != nil {
+ dw.outFile.EventUnregister(&dw.outW)
+ dw.outCh = nil
}
+ dw.inFile = nil
+ dw.outFile = nil
}
diff --git a/pkg/sentry/syscalls/linux/vfs2/vfs2.go b/pkg/sentry/syscalls/linux/vfs2/vfs2.go
index 8f497ecc7..1b2cfad7d 100644
--- a/pkg/sentry/syscalls/linux/vfs2/vfs2.go
+++ b/pkg/sentry/syscalls/linux/vfs2/vfs2.go
@@ -44,7 +44,7 @@ func Override() {
s.Table[23] = syscalls.Supported("select", Select)
s.Table[32] = syscalls.Supported("dup", Dup)
s.Table[33] = syscalls.Supported("dup2", Dup2)
- delete(s.Table, 40) // sendfile
+ s.Table[40] = syscalls.Supported("sendfile", Sendfile)
s.Table[41] = syscalls.Supported("socket", Socket)
s.Table[42] = syscalls.Supported("connect", Connect)
s.Table[43] = syscalls.Supported("accept", Accept)
diff --git a/test/syscalls/BUILD b/test/syscalls/BUILD
index c06a75ada..15e5fd223 100644
--- a/test/syscalls/BUILD
+++ b/test/syscalls/BUILD
@@ -640,11 +640,13 @@ syscall_test(
syscall_test(
add_overlay = True,
test = "//test/syscalls/linux:sendfile_socket_test",
+ vfs2 = "True",
)
syscall_test(
add_overlay = True,
test = "//test/syscalls/linux:sendfile_test",
+ vfs2 = "True",
)
syscall_test(
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 20:35:20 +0000