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, 13 insertions, 7 deletions

diff --git a/ext/spl/spl_directory.c b/ext/spl/spl_directory.c
index 1fdaacb588..9f70a2c867 100644
--- a/ext/spl/spl_directory.c
+++ b/ext/spl/spl_directory.c
@@ -2896,7 +2896,7 @@ SPL_METHOD(SplFileObject, fscanf)
 }
 /* }}} */
 
-/* {{{ proto mixed SplFileObject::fwrite(string str [, int length])
+/* {{{ proto int|false SplFileObject::fwrite(string str [, int length])
    Binary-safe file write */
 SPL_METHOD(SplFileObject, fwrite)
 {
@@ -2904,6 +2904,7 @@ SPL_METHOD(SplFileObject, fwrite)
 	char *str;
 	size_t str_len;
 	zend_long length = 0;
+	ssize_t written;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS(), "s|l", &str, &str_len, &length) == FAILURE) {
 		return;
@@ -2926,13 +2927,18 @@ SPL_METHOD(SplFileObject, fwrite)
 		RETURN_LONG(0);
 	}
 
-	RETURN_LONG(php_stream_write(intern->u.file.stream, str, str_len));
+	written = php_stream_write(intern->u.file.stream, str, str_len);
+	if (written < 0) {
+		RETURN_FALSE;
+	}
+	RETURN_LONG(written);
 } /* }}} */
 
 SPL_METHOD(SplFileObject, fread)
 {
 	spl_filesystem_object *intern = Z_SPLFILESYSTEM_P(ZEND_THIS);
 	zend_long length = 0;
+	zend_string *str;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS(), "l", &length) == FAILURE) {
 		return;
@@ -2948,11 +2954,11 @@ SPL_METHOD(SplFileObject, fread)
 		RETURN_FALSE;
 	}
 
-	ZVAL_NEW_STR(return_value, zend_string_alloc(length, 0));
-	Z_STRLEN_P(return_value) = php_stream_read(intern->u.file.stream, Z_STRVAL_P(return_value), length);
-
-	/* needed because recv/read/gzread doesn't put a null at the end*/
-	Z_STRVAL_P(return_value)[Z_STRLEN_P(return_value)] = 0;
+	str = php_stream_read_to_str(intern->u.file.stream, length);
+	if (!str) {
+		RETURN_FALSE;
+	}
+	RETURN_STR(str);
 }
 
 /* {{{ proto bool SplFileObject::fstat()