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, 8 insertions, 8 deletions

diff --git a/ext/sqlite3/sqlite3.c b/ext/sqlite3/sqlite3.c
index 429be63cb6..1c337ee6cb 100644
--- a/ext/sqlite3/sqlite3.c
+++ b/ext/sqlite3/sqlite3.c
@@ -1125,22 +1125,22 @@ typedef struct {
 	int          flags;
 } php_stream_sqlite3_data;
 
-static size_t php_sqlite3_stream_write(php_stream *stream, const char *buf, size_t count)
+static ssize_t php_sqlite3_stream_write(php_stream *stream, const char *buf, size_t count)
 {
 	php_stream_sqlite3_data *sqlite3_stream = (php_stream_sqlite3_data *) stream->abstract;
 
 	if (sqlite3_stream->flags & SQLITE_OPEN_READONLY) {
 		php_error_docref(NULL, E_WARNING, "Can't write to blob stream: is open as read only");
-		return 0;
+		return -1;
 	}
 
 	if (sqlite3_stream->position + count > sqlite3_stream->size) {
 		php_error_docref(NULL, E_WARNING, "It is not possible to increase the size of a BLOB");
-		return 0;
+		return -1;
 	}
 
 	if (sqlite3_blob_write(sqlite3_stream->blob, buf, count, sqlite3_stream->position) != SQLITE_OK) {
-		return 0;
+		return -1;
 	}
 
 	if (sqlite3_stream->position + count >= sqlite3_stream->size) {
@@ -1154,7 +1154,7 @@ static size_t php_sqlite3_stream_write(php_stream *stream, const char *buf, size
 	return count;
 }
 
-static size_t php_sqlite3_stream_read(php_stream *stream, char *buf, size_t count)
+static ssize_t php_sqlite3_stream_read(php_stream *stream, char *buf, size_t count)
 {
 	php_stream_sqlite3_data *sqlite3_stream = (php_stream_sqlite3_data *) stream->abstract;
 
@@ -1164,7 +1164,7 @@ static size_t php_sqlite3_stream_read(php_stream *stream, char *buf, size_t coun
 	}
 	if (count) {
 		if (sqlite3_blob_read(sqlite3_stream->blob, buf, count, sqlite3_stream->position) != SQLITE_OK) {
-			return 0;
+			return -1;
 		}
 		sqlite3_stream->position += count;
 	}
diff --git a/ext/sqlite3/tests/sqlite3_30_blobopen.phpt b/ext/sqlite3/tests/sqlite3_30_blobopen.phpt
index 2e9a9f2be2..25d4a7abc2 100644
--- a/ext/sqlite3/tests/sqlite3_30_blobopen.phpt
+++ b/ext/sqlite3/tests/sqlite3_30_blobopen.phpt
@@ -60,7 +60,7 @@ string(9) "TEST TEST"
 Writing to read-only stream
 
 Warning: fwrite(): Can't write to blob stream: is open as read only in %s on line %d
-int(0)
+bool(false)
 Closing Stream
 bool(true)
 Opening stream in write mode
@@ -72,7 +72,7 @@ string(9) "ABCD TEST"
 Expanding blob size
 
 Warning: fwrite(): It is not possible to increase the size of a BLOB in %s on line %d
-int(0)
+bool(false)
 Closing Stream
 bool(true)
 Closing database