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internal/pipewire: handle dangling files in roundtrip

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This should not be handled on every receive as it could cause valid (though impossible in current upstream implementation) messages to be rejected and raise a protocol error.

Signed-off-by: Ophestra <cat@gensokyo.uk>
This commit is contained in:
Ophestra
2025-12-06 19:21:57 +09:00
parent 7cb3308a53
commit 5e7861bb00
1 changed files with 30 additions and 44 deletions
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74
internal/pipewire/pipewire.go
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@@ -571,6 +571,36 @@ func (ctx *Context) roundtrip() (err error) {
return
}
defer func() {
var danglingFiles DanglingFilesError
if len(ctx.receivedFiles) > 0 {
// having multiple *os.File with the same fd causes serious problems
slices.Sort(ctx.receivedFiles)
ctx.receivedFiles = slices.Compact(ctx.receivedFiles)
danglingFiles = make(DanglingFilesError, 0, len(ctx.receivedFiles))
for _, fd := range ctx.receivedFiles {
// hold these as *os.File so they are closed if this error never reaches the caller,
// or the caller discards or otherwise does not handle this error, to avoid leaking fds
danglingFiles = append(danglingFiles, os.NewFile(uintptr(fd),
"dangling fd "+strconv.Itoa(fd)+" received from PipeWire"))
}
ctx.receivedFiles = ctx.receivedFiles[:0]
}
// populated early for finalizers, but does not overwrite existing errors
if len(danglingFiles) > 0 && err == nil {
err = &ProxyFatalError{Err: danglingFiles, ProxyErrs: ctx.cloneAsProxyErrors()}
return
}
// this check must happen after everything else passes
if len(ctx.pendingIds) != 0 {
err = &ProxyFatalError{Err: UnacknowledgedProxyError(slices.Collect(maps.Keys(ctx.pendingIds))), ProxyErrs: ctx.cloneAsProxyErrors()}
return
}
}()
var remaining []byte
for {
remaining, err = ctx.consume(remaining)
@@ -595,22 +625,6 @@ func (ctx *Context) roundtrip() (err error) {
// consume receives messages from the server and processes events.
func (ctx *Context) consume(receiveRemaining []byte) (remaining []byte, err error) {
defer func() {
// anything before this has already been processed and must not be closed
// here, as anything holding onto them will end up with a dangling fd that
// can be reused and cause serious problems
if len(ctx.receivedFiles) > 0 {
ctx.closeReceivedFiles()
// this catches cases where Roundtrip somehow returns without processing
// all received files or preparing an error for dangling files, this is
// always overwritten by the fatal error being processed below or made
// inaccessible due to repanicking, so if this ends up returned to the
// caller it indicates something has gone seriously wrong in Roundtrip
if err == nil {
err = syscall.ENOTRECOVERABLE
}
}
r := recover()
if r == nil {
return
@@ -677,34 +691,6 @@ func (ctx *Context) consume(receiveRemaining []byte) (remaining []byte, err erro
ctx.proxyErrors = append(ctx.proxyErrors, proxyErr)
}
}
// prepared here so finalizers are set up, but should not prevent proxyErrors
// from reaching the caller as those describe the cause of these dangling fds
var danglingFiles DanglingFilesError
if len(ctx.receivedFiles) > 0 {
// having multiple *os.File with the same fd causes serious problems
slices.Sort(ctx.receivedFiles)
ctx.receivedFiles = slices.Compact(ctx.receivedFiles)
danglingFiles = make(DanglingFilesError, 0, len(ctx.receivedFiles))
for _, fd := range ctx.receivedFiles {
// hold these as *os.File so they are closed if this error never reaches the caller,
// or the caller discards or otherwise does not handle this error, to avoid leaking fds
danglingFiles = append(danglingFiles, os.NewFile(uintptr(fd),
"dangling fd "+strconv.Itoa(fd)+" received from PipeWire"))
}
ctx.receivedFiles = ctx.receivedFiles[:0]
}
// populated early for finalizers
if len(danglingFiles) > 0 {
return remaining, danglingFiles
}
// this check must happen after everything else passes
if len(ctx.pendingIds) != 0 {
return remaining, UnacknowledgedProxyError(slices.Collect(maps.Keys(ctx.pendingIds)))
}
return
}