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/standard/ftp_fopen_wrapper.c b/ext/standard/ftp_fopen_wrapper.c
index 71a511746d..3a7dec4a3b 100644
--- a/ext/standard/ftp_fopen_wrapper.c
+++ b/ext/standard/ftp_fopen_wrapper.c
@@ -613,7 +613,7 @@ errexit:
 
 /* {{{ php_ftp_dirsteam_read
  */
-static size_t php_ftp_dirstream_read(php_stream *stream, char *buf, size_t count)
+static ssize_t php_ftp_dirstream_read(php_stream *stream, char *buf, size_t count)
 {
 	php_stream_dirent *ent = (php_stream_dirent *)buf;
 	php_stream *innerstream;
@@ -623,7 +623,7 @@ static size_t php_ftp_dirstream_read(php_stream *stream, char *buf, size_t count
 	innerstream =  ((php_ftp_dirstream_data *)stream->abstract)->datastream;
 
 	if (count != sizeof(php_stream_dirent)) {
-		return 0;
+		return -1;
 	}
 
 	if (php_stream_eof(innerstream)) {
@@ -631,7 +631,7 @@ static size_t php_ftp_dirstream_read(php_stream *stream, char *buf, size_t count
 	}
 
 	if (!php_stream_get_line(innerstream, ent->d_name, sizeof(ent->d_name), &tmp_len)) {
-		return 0;
+		return -1;
 	}
 
 	basename = php_basename(ent->d_name, tmp_len, NULL, 0);