Here is an analysis of the situation as it stands with PHP 4.3.3. As far as I can tell that even when opening files with the full path we do a lot of completely unnecessary work.
We start from expand_filepath() which, gets called when opening a file. This function does a getcwd() everytime it is called even if path is full (/path/to/script.php), as far as I can tell completely useless syscal.
Two different full paths can point to the same file and not using realpath() would break include_once() and require_once().
We might be able to use stat() information to compare the files but it would require some thinking.
Andi
Inside virtual_file_ex(), which gets called by expand_filepath(), even when the path is full we tokenize the path and validate every directory for '.' & '..' instead of just checking for . + DIR_SEPARATOR and only doing this work if such a thing exists. Quite a bit of completely useless cpu trashing in most cases everytime we open a file.
Now, the interesting part, which I've yet to track down, are 6 lstat64() calls
that occur between getcwd() (look above) and the actual open() for every file
opened by PHP regardless of whether it had a full path or not.
Here is strace bit:
getcwd("/home/rei/PHP_CVS/STABLE/php4", 4096) = 30 <0.000011> lstat64(0xbfffad30, 0xbfffac90) = 0 <0.000015> lstat64(0xbfffad30, 0xbfffac90) = 0 <0.000008> lstat64(0xbfffad30, 0xbfffac90) = 0 <0.000008> lstat64(0xbfffad30, 0xbfffac90) = 0 <0.000008> lstat64(0xbfffad30, 0xbfffac90) = 0 <0.000008> lstat64(0xbfffad30, 0xbfffac90) = 0 <0.000009> open("/home/rei/PHP_CVS/STABLE/php4/file.html", O_RDONLY) = 4 <0.000018>
Ilia
P.S. I used the term 'unnecessary' because removing the mention code does not seem to affect the script's behaviour only makes it work faster.
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