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.

2 files changed, 2 insertions, 2 deletions

diff --git a/sapi/phpdbg/phpdbg.c b/sapi/phpdbg/phpdbg.c
index 1f4cb29a4f..17de15fa91 100644
--- a/sapi/phpdbg/phpdbg.c
+++ b/sapi/phpdbg/phpdbg.c
@@ -955,7 +955,7 @@ typedef struct {
 	int fd;
 } php_stdio_stream_data;
 
-static size_t phpdbg_stdiop_write(php_stream *stream, const char *buf, size_t count) {
+static ssize_t phpdbg_stdiop_write(php_stream *stream, const char *buf, size_t count) {
 	php_stdio_stream_data *data = (php_stdio_stream_data*)stream->abstract;
 
 	while (data->fd >= 0) {
diff --git a/sapi/phpdbg/phpdbg.h b/sapi/phpdbg/phpdbg.h
index d1b22e6f40..d0e316c78b 100644
--- a/sapi/phpdbg/phpdbg.h
+++ b/sapi/phpdbg/phpdbg.h
@@ -290,7 +290,7 @@ ZEND_BEGIN_MODULE_GLOBALS(phpdbg)
 		int fd;
 	} io[PHPDBG_IO_FDS];                         /* io */
 	int eol;                                     /* type of line ending to use */
-	size_t (*php_stdiop_write)(php_stream *, const char *, size_t);
+	ssize_t (*php_stdiop_write)(php_stream *, const char *, size_t);
 	int in_script_xml;                           /* in <stream> output mode */
 	struct {
 		zend_bool active;