php file_put_contents no such file or directory occasionally

Question

I start 8 processes to execute a job, the code in the job like this:

<?php
$dir = "/home/test/fileputcontents/0";
if(! is_dir($dir)){
    mkdir($dir, 0755, true);
}
file_put_contents("{$dir}/0.txt", "aaaa\n", FILE_APPEND | LOCK_EX);

but it raises an error which say "No such file or directory" sometimes，not very offen, thanks very much.

Is it because php_mkdir_ex method? Multi-process create directory at the same time.

/* DEPRECATED APIs: Use php_stream_mkdir() instead */
PHPAPI int php_mkdir_ex(const char *dir, zend_long mode, int options)
{
    int ret;

    if (php_check_open_basedir(dir)) {
        return -1;
    }

    if ((ret = VCWD_MKDIR(dir, (mode_t)mode)) < 0 && (options & REPORT_ERRORS)) {
        php_error_docref(NULL, E_WARNING, "%s", strerror(errno));
    }

    return ret;
}

Is there something wrong with muli-processes? the php version is 7.4.5，CentOS Linux release 7.4.1708 (Core)，GNU coreutils 8.22 November 2016 — wlstony, Jul 30 '20 at 08:16
Is there anything else in the script? Why do you need to create the directory every time? Maybe you removed some of the code to make it easier to post, but it is part of what causes the error? — noam, Jul 30 '20 at 08:22
Yes, The sript is used to export mysql data to file。before write to the file, It checkout dir every time — wlstony, Jul 30 '20 at 08:30
@noam， I removed "create directories recursively"，Thanks for your answer. — wlstony, Jan 15 '21 at 07:22

score 2 · Accepted Answer · edited Jan 15 '21 at 07:36

2

Finally, I found the reason from php source code. It's because the directory creation collision. For example:

We have 2 processes to create directory "/home/test/fileputcontents/0" at the same time.
Now only /home directory exists, we need create test/fileputcontents/0
One process (we call A) has created test, is going to create fileputcontents，anther process (we call B) is going to create test again, but it already exists.
Then process B stopping creating directory, because it thinks all directories exist
When B tries to call file_put_contents before A creates all the directories, then it warns "No such file or directory", because fileputcontents/0 does not exist.

My solution, create directories because processes start.

edited Jan 15 '21 at 07:36

Martin Brisiak

3,872
12
37
51

answered Jan 15 '21 at 07:14

wlstony

43
1
8

This is amazing. – Jehong Ahn Dec 06 '21 at 08:23
https://bugs.php.net/bug.php?id=35326 – Jehong Ahn Dec 06 '21 at 08:29
Oh.. fixed in 8.1 – Jehong Ahn Dec 06 '21 at 18:58

score 0 · Answer 2 · answered Jul 30 '20 at 08:41

0

Are all 8 processes running at the same time and writing to the same file? If two processes would write in the file at the same moment, it could be possible that the file is locked (caused by the LOCK_EX flag). So one process would win (can write to the file) and the other one would not wait, instead an error would be raised.

answered Jul 30 '20 at 08:41

Martin

101
3

8 processes write different files, but in the same directory. – wlstony Jul 30 '20 at 08:44

score 0 · Answer 3 · answered Dec 06 '21 at 18:57

0

Fixed in 8.1

https://github.com/php/php-src/pull/7383

- if (ret < 0) {
+ if (ret < 0 && errno != EEXIST) {

answered Dec 06 '21 at 18:57

Jehong Ahn

1,872
1
19
25

php file_put_contents no such file or directory occasionally

3 Answers3