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, 6 insertions, 6 deletions

diff --git a/ext/standard/php_fopen_wrapper.c b/ext/standard/php_fopen_wrapper.c
index 053f8417ec..aba826d7b3 100644
--- a/ext/standard/php_fopen_wrapper.c
+++ b/ext/standard/php_fopen_wrapper.c
@@ -31,17 +31,17 @@
 #include "php_fopen_wrappers.h"
 #include "SAPI.h"
 
-static size_t php_stream_output_write(php_stream *stream, const char *buf, size_t count) /* {{{ */
+static ssize_t php_stream_output_write(php_stream *stream, const char *buf, size_t count) /* {{{ */
 {
 	PHPWRITE(buf, count);
 	return count;
 }
 /* }}} */
 
-static size_t php_stream_output_read(php_stream *stream, char *buf, size_t count) /* {{{ */
+static ssize_t php_stream_output_read(php_stream *stream, char *buf, size_t count) /* {{{ */
 {
 	stream->eof = 1;
-	return 0;
+	return -1;
 }
 /* }}} */
 
@@ -69,16 +69,16 @@ typedef struct php_stream_input { /* {{{ */
 } php_stream_input_t;
 /* }}} */
 
-static size_t php_stream_input_write(php_stream *stream, const char *buf, size_t count) /* {{{ */
+static ssize_t php_stream_input_write(php_stream *stream, const char *buf, size_t count) /* {{{ */
 {
 	return -1;
 }
 /* }}} */
 
-static size_t php_stream_input_read(php_stream *stream, char *buf, size_t count) /* {{{ */
+static ssize_t php_stream_input_read(php_stream *stream, char *buf, size_t count) /* {{{ */
 {
 	php_stream_input_t *input = stream->abstract;
-	size_t read;
+	ssize_t read;
 
 	if (!SG(post_read) && SG(read_post_bytes) < (int64_t)(input->position + count)) {
 		/* read requested data from SAPI */