Report errors from stream read and write operations

The php_stream_read() and php_stream_write() functions now return
an ssize_t value, with negative results indicating failure. Functions
like fread() and fwrite() will return false in that case.

As a special case, EWOULDBLOCK and EAGAIN on non-blocking streams
should not be regarded as error conditions, and be reported as
successful zero-length reads/writes instead. The handling of EINTR
remains unclear and is internally inconsistent (e.g. some code-paths
will automatically retry on EINTR, while some won't).

I'm landing this now to make sure the stream wrapper ops API changes
make it into 7.4 -- however, if the user-facing changes turn out to
be problematic we have the option of clamping negative returns to
zero in php_stream_read() and php_stream_write() to restore the
old behavior in a relatively non-intrusive manner.

1 files changed, 3 insertions, 3 deletions

diff --git a/ext/com_dotnet/com_persist.c b/ext/com_dotnet/com_persist.c
index 89c100b0fa..9be79995a3 100644
--- a/ext/com_dotnet/com_persist.c
+++ b/ext/com_dotnet/com_persist.c
@@ -118,13 +118,13 @@ static HRESULT STDMETHODCALLTYPE stm_read(IStream *This, void *pv, ULONG cb, ULO
 
 static HRESULT STDMETHODCALLTYPE stm_write(IStream *This, void const *pv, ULONG cb, ULONG *pcbWritten)
 {
-	ULONG nwrote;
+	ssize_t nwrote;
 	FETCH_STM();
 
-	nwrote = (ULONG)php_stream_write(stm->stream, pv, cb);
+	nwrote = php_stream_write(stm->stream, pv, cb);
 
 	if (pcbWritten) {
-		*pcbWritten = nwrote > 0 ? nwrote : 0;
+		*pcbWritten = nwrote > 0 ? (ULONG)nwrote : 0;
 	}
 	if (nwrote > 0) {
 		return S_OK;