I had a really strange problem, I was writing a tiny Python script to learn about Python and it was writing to \/var\/tmp. Only problem was the file never turned up. This script was run from within Apache 2 on Fedora 18.<\/p>\n
The file I was trying to create was “webhook_current_json_request.json<\/em>“. Turns out the problem is Apache when run using systemd. This is what I found.<\/p>\n Looking at “man system.unit” we see:<\/p>\n PrivateTmp= I found my systemctl .service file for Apache, “httpd” at:<\/p>\n \/usr\/lib\/systemd\/system\/httpd.service<\/p>\n It looked like:<\/p>\n As the man page states “sets up a new file system namespace for the executed processes and mounts private \/tmp and \/var\/tmp directories inside it<\/em>” it transpires the “new file system namespace<\/em>” is a somewhat random folder under \/var\/tmp. These look like:<\/p>\n I did some digging and found the one which Apache was currently using “systemd-private-JgJxbB” and inside it I found my file<\/p>\n \/var\/tmp\/systemd-private-JgJxbB\/tmp\/webhook_current_json_request.json<\/p>\n Moral of the story seems to be not to write to \/tmp or \/var\/tmp when running in Apache.<\/p>\n","protected":false},"excerpt":{"rendered":" I had a really strange problem, I was writing a tiny Python script to learn about Python and it was writing to \/var\/tmp. Only problem was the file never turned up. This script was run from within Apache 2 on Fedora 18. The file I was trying to create was “webhook_current_json_request.json“. Turns out the problem […]<\/p>\n","protected":false},"author":2,"featured_media":1473,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[85,5,433],"tags":[435,436,305,434,437,430,439,440,441,438],"class_list":["post-3191","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-apache","category-fedora","category-python","tag-tmp","tag-var-tmp","tag-apache","tag-httpd","tag-permissions","tag-python","tag-read","tag-systemd","tag-systemdtl","tag-write"],"_links":{"self":[{"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=\/wp\/v2\/posts\/3191","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3191"}],"version-history":[{"count":6,"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=\/wp\/v2\/posts\/3191\/revisions"}],"predecessor-version":[{"id":3197,"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=\/wp\/v2\/posts\/3191\/revisions\/3197"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=\/wp\/v2\/media\/1473"}],"wp:attachment":[{"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3191"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3191"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.zoyinc.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3191"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nTakes a boolean argument. If true sets up a new file system namespace for the executed processes and mounts private \/tmp and \/var\/tmp<\/span> directories inside it, that are not
\nshared by processes outside of the namespace. This is useful to secure access to temporary files of the process, but makes sharing between processes via \/tmp or \/var\/tmp
\nimpossible. All temporary data created by service will be removed after service is stopped. Defaults to false.<\/p><\/blockquote>\n[Unit]\r\nDescription=The Apache HTTP Server\r\nAfter=network.target remote-fs.target nss-lookup.target\r\n\r\n[Service]\r\nType=notify\r\nEnvironmentFile=\/etc\/sysconfig\/httpd\r\nExecStart=\/usr\/sbin\/httpd $OPTIONS -DFOREGROUND\r\nExecReload=\/usr\/sbin\/httpd $OPTIONS -k graceful\r\nExecStop=\/usr\/sbin\/httpd $OPTIONS -k graceful-stop\r\n# We want systemd to give httpd some time to finish gracefully, but still want\r\n# it to kill httpd after TimeoutStopSec if something went wrong during the\r\n# graceful stop. Normally, Systemd sends SIGTERM signal right after the\r\n# ExecStop, which would kill httpd. We are sending useless SIGCONT here to give\r\n# httpd time to finish.\r\nKillSignal=SIGCONT\r\nPrivateTmp=true\r\n\r\n[Install]\r\nWantedBy=multi-user.target\r\n<\/pre>\n
[root@vmvaliant tmp]# cd \/var\/tmp\r\n[root@vmvaliant tmp]# ll\r\ntotal 304\r\ndrwxr-xr-x 2 abrt abrt 4096 Jul 6 08:48 abrt\r\ndrwx------ 3 root root 4096 Jul 8 2015 systemd-private-0zBSJE\r\ndrwx------ 3 root root 4096 Apr 27 10:38 systemd-private-1aUPmp\r\ndrwx------ 3 root root 4096 Aug 20 2017 systemd-private-1T74Sw\r\ndrwx------ 3 root root 4096 Aug 29 2017 systemd-private-1VhcnW\r\ndrwx------ 3 root root 4096 Aug 20 2017 systemd-private-7BmxdZ\r\ndrwx------ 3 root root 4096 Dec 9 2017 systemd-private-8cXaI2<\/pre>\n