Edit report at http://bugs.php.net/bug.php?id=51056&edit=1
ID: 51056
Updated by: lbarn...@php.net
Reported by: magical...@php.net
Summary: fread() on blocking stream will block even if data is
available
Status: Open
Type: Bug
Package: Streams related
Operating System: Linux Gentoo 2.6.32
PHP Version: 5.3.1
New Comment:
Hi,
I made a test case for this ( 51056.phpt.txt )
fread() in C has exactly the same behavior, it will block if you try to
read more bytes than available.
Your patch correctly avoids this, however it introduces an other issue:
fread() will return less data than asked for, even if enough data is
available ( 51056-2.phpt.txt ).
Previous Comments:
------------------------------------------------------------------------
[2010-02-17 16:00:07] j...@php.net
btw. If you really want someone to do something about this, post the
patch to intern...@lists.php.net as well. :)
------------------------------------------------------------------------
[2010-02-17 05:39:56] magical...@php.net
While for file sockets it makes sense when reading data to make sure a
buffer gets completly filled until EOF is reached, this is not true
for sockets.
There is already a condition for "greedy read", but it does not apply
when we first restore data from the read buffer.
Here is a diff (PHP_5_3) that solves the issue:
Index: main/streams/streams.c
===================================================================
--- main/streams/streams.c (révision 295152)
+++ main/streams/streams.c (copie de travail)
@@ -592,6 +592,10 @@
size -= toread;
buf += toread;
didread += toread;
+
+ /* avoid trying to read if we already have
data to pass */
+ if (stream->wrapper !=
&php_plain_files_wrapper)
+ break;
}
/* ignore eof here; the underlying state might have
changed */
Test script output:
Testing PHP version: 5.3.3-dev
fread took 0.07ms to read 8 bytes
fread took 5.07ms to read 256 bytes
fread took 0.00ms to read 45 bytes
fread took 1000.11ms to read 8 bytes
fread took 5.02ms to read 256 bytes
fread took 0.00ms to read 45 bytes
fread took 1000.13ms to read 8 bytes
fread took 5.04ms to read 256 bytes
------------------------------------------------------------------------
[2010-02-16 13:06:45] magical...@php.net
I tried to switch to non-blocking mode. This solves this issue with
most sockets, except for SSL sockets when transmitting a lot of data.
This bug is blocking in my case (socket communication transmitting a
lot of data).
------------------------------------------------------------------------
[2010-02-16 12:19:38] fel...@php.net
Testing PHP version: 5.2.13RC3-dev
fread took 0.04ms to read 8 bytes
fread took 4.88ms to read 256 bytes
fread took 1000.04ms to read 53 bytes
fread took 4.96ms to read 256 bytes
fread took 1000.06ms to read 53 bytes
fread took 4.97ms to read 256 bytes
fread took 1000.06ms to read 53 bytes
(etc)
------------------------------------------------------------------------
[2010-02-16 12:00:52] magical...@php.net
Confirmed with PHP_5_3
Testing PHP version: 5.3.3-dev
fread took 0.07ms to read 8 bytes
fread took 5.06ms to read 256 bytes
fread took 1000.10ms to read 53 bytes
fread took 5.03ms to read 256 bytes
fread took 1000.11ms to read 53 bytes
fread took 5.04ms to read 256 bytes
fread took 1000.10ms to read 53 bytes
I'll need a bit more time for PHP_5_2 as flex-2.5.4 is becoming more
difficult to find.
------------------------------------------------------------------------
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