Bug #52312 [Bgs]: PHP lstat problem

Edit report at http://bugs.php.net/bug.php?id=52312&edit=1 ID: 52312 Updated by: rasmus@php.net Reported by: v dot damore at gmail dot com Summary: PHP lstat problem Status: Bogus Type: Bug Package: Safe Mode/open_basedir Operating System: Linux PHP Version: 5.2.13 New Comment: phpinfo() is a special case. Try it with a simple hello world script. Previous Comments: ------------------------------------------------------------------------ [2010-07-12 16:56:36] v dot damore at gmail dot com The real problem is that such full scan are repeated more then once: 25933 lstat("/usr", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace/httpdocs", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace/httpdocs/phpinfo.php", {st_mode=S_IFREG|0644, st_size=16, ...}) = 0 First check 25933 lstat("/usr", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace/httpdocs", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace/httpdocs/phpinfo.php", {st_mode=S_IFREG|0644, st_size=16, ...}) = 0 Second check 25933 lstat("/usr", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 Third check (incomplete) 25933 lstat("/usr", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace/httpdocs", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0 25933 lstat("/usr/local/myspace/webspace/httpdocs/phpinfo.php", {st_mode=S_IFREG|0644, st_size=16, ...}) = 0 Final check and then read the file. 25933 open("/usr/local/myspace/webspace/httpdocs/phpinfo.php", O_RDONLY) = 16 25933 fstat(16, {st_mode=S_IFREG|0644, st_size=16, ...}) = 0 25933 read(16, "<? phpinfo() ?>\n", 8192) = 16 25933 read(16, "", 8192) = 0 25933 read(16, "", 8192) = 0 25933 close(16) = 0 ------------------------------------------------------------------------ [2010-07-12 16:35:46] pajoye@php.net The scan of each element of the paths happen anyway, whether the paths contain symlinks or not. Check the code TSRM/ for a deeper explanation. ------------------------------------------------------------------------ [2010-07-12 15:57:54] v dot damore at gmail dot com @pajoye; as is described in "Actual result" part of this bug, first time PHP engine check filepath there is a full scan of all directories at least 4 times before cache the result, this behavior anyway cannot scale in a so large environment. @rasmus: this is very interesting, I can consider upgrade to 5.3 in order to avoid this behavior. I know this is an extrema ratio: may I disable symlinks support from PHP engine in order to avoid this behavior? Is there an answer regarding the increase of realpath_cache_size realpath_cache_ttl? ------------------------------------------------------------------------ [2010-07-12 15:36:10] rasmus@php.net And like I said, we have made this more efficient in PHP 5.3 because we now cache the partial paths separately. You should see a performance improvement going to 5.3. ------------------------------------------------------------------------ [2010-07-12 15:32:33] pajoye@php.net Again, it does it once and only once per path. When it does it, it checks each element of a path (and cache each of them too). ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/bug.php?id=52312 -- Edit this bug report at http://bugs.php.net/bug.php?id=52312&edit=1