Fix phpGH-10834: exif_read_data() cannot read smaller stream wrapper chunk sizes

Exif uses php_stream_read() to read data from the stream and process it.
In this case, it's a userspace stream. Userspace streams can either by
local or url streams.

In 5060fc2 and subsequently 0a45e8f, the behaviour of the
check was changed twice in total. In the latter commit the description
talks about exceptions for streams that are local to the process. It
looks like the exception for local userspace streams was forgotten. This
patch updates the check such that local userspace streams also read
greedily, while keeping url userspace streams unchanged.

This also updates the existing test to test both local and url userspace
streams.

Author: nielsdos

ext/standard/tests/streams/stream_set_chunk_size.phpt

@@ -24,45 +24,87 @@ class test_wrapper {
     }
 }
 
-var_dump(stream_wrapper_register('test', 'test_wrapper'));
+var_dump(stream_wrapper_register('testlocal', 'test_wrapper'));
+var_dump(stream_wrapper_register('testurl', 'test_wrapper', STREAM_IS_URL));
 
-$f = fopen("test://foo","r");
+foreach (['testlocal', 'testurl'] as $stream_type) {
+    $f = fopen("$stream_type://foo","r");
 
-/* when the chunk size is 1, the read buffer is skipped, but the
- * the writes are made in chunks of size 1 (business as usual)
- * This should probably be revisited */
-echo "should return previous chunk size (8192)\n";
-var_dump(stream_set_chunk_size($f, 1));
-echo "should be read without buffer (\$count == 10000)\n";
-var_dump(strlen(fread($f, 10000)));
-echo "should have no effect on writes\n";
-var_dump(fwrite($f, str_repeat('b', 3)));
+    /* when the chunk size is 1, the read buffer is skipped, but the
+     * writes are made in chunks of size 1 (business as usual)
+     * This should probably be revisited */
+    echo "should return previous chunk size (8192)\n";
+    var_dump(stream_set_chunk_size($f, 1));
+    echo "should be read without buffer (\$count == 10000)\n";
+    var_dump(strlen(fread($f, 10000)));
+    echo "should have no effect on writes\n";
+    var_dump(fwrite($f, str_repeat('b', 3)));
 
-echo "should return previous chunk size (1)\n";
-var_dump(stream_set_chunk_size($f, 100));
-echo "should elicit one read of size 100 (chunk size)\n";
-var_dump(strlen(fread($f, 250)));
-echo "should elicit one read of size 100 (chunk size)\n";
-var_dump(strlen(fread($f, 50)));
-echo "should elicit no read because there is sufficient cached data\n";
-var_dump(strlen(fread($f, 50)));
-echo "should have no effect on writes\n";
-var_dump(strlen(fwrite($f, str_repeat('b', 250))));
+    echo "should return previous chunk size (1)\n";
+    var_dump(stream_set_chunk_size($f, 100));
+    if ($stream_type === 'testurl') {
+        echo "should elicit one read of size 100 (chunk size)\n";
+        var_dump(strlen(fread($f, 250)));
+        echo "should elicit one read of size 100 (chunk size)\n";
+        var_dump(strlen(fread($f, 50)));
+        echo "should elicit no read because there is sufficient cached data\n";
+        var_dump(strlen(fread($f, 50)));
+    } else { // testlocal
+        echo "should elicit 3 reads of size 100 (chunk size)\n";
+        var_dump(strlen(fread($f, 250)));
+        echo "should not elicit a read\n";
+        var_dump(strlen(fread($f, 50)));
+        echo "should elicit a read because there is insufficient cached data\n";
+        var_dump(strlen(fread($f, 50)));
+    }
+    echo "should have no effect on writes\n";
+    var_dump(strlen(fwrite($f, str_repeat('b', 250))));
 
-echo "\nerror conditions\n";
-try {
-    stream_set_chunk_size($f, 0);
-} catch (ValueError $exception) {
-    echo $exception->getMessage() . "\n";
-}
-try {
-    stream_set_chunk_size($f, -1);
-} catch (ValueError $exception) {
-    echo $exception->getMessage() . "\n";
+    echo "\nerror conditions\n";
+    try {
+        stream_set_chunk_size($f, 0);
+    } catch (ValueError $exception) {
+        echo $exception->getMessage() . "\n";
+    }
+    try {
+        stream_set_chunk_size($f, -1);
+    } catch (ValueError $exception) {
+        echo $exception->getMessage() . "\n";
+    }
+
+    fclose($f);
 }
 ?>
 --EXPECT--
 bool(true)
+bool(true)
+should return previous chunk size (8192)
+int(8192)
+should be read without buffer ($count == 10000)
+read with size: 10000
+int(10000)
+should have no effect on writes
+write with size: 3
+int(3)
+should return previous chunk size (1)
+int(1)
+should elicit 3 reads of size 100 (chunk size)
+read with size: 100
+read with size: 100
+read with size: 100
+int(250)
+should not elicit a read
+int(50)
+should elicit a read because there is insufficient cached data
+read with size: 100
+int(50)
+should have no effect on writes
+write with size: 250
+int(3)
+
+error conditions
+stream_set_chunk_size(): Argument #2 ($size) must be greater than 0
+stream_set_chunk_size(): Argument #2 ($size) must be greater than 0
 should return previous chunk size (8192)
 int(8192)
 should be read without buffer ($count == 10000)

main/streams/streams.c

@@ -748,7 +748,8 @@ PHPAPI ssize_t _php_stream_read(php_stream *stream, char *buf, size_t size)
 		/* just break anyway, to avoid greedy read for file://, php://memory, and php://temp */
 		if ((stream->wrapper != &php_plain_files_wrapper) &&
 			(stream->ops != &php_stream_memory_ops) &&
-			(stream->ops != &php_stream_temp_ops)) {
+			(stream->ops != &php_stream_temp_ops) &&
+			!(stream->ops == &php_stream_userspace_ops && !stream->wrapper->is_url)) {
 			break;
 		}
 	}