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Full Discussion: chown: Read-only file system
Top Forums UNIX for Dummies Questions & Answers chown: Read-only file system Post 302644147 by Clovis_Sangrail on Monday 21st of May 2012 11:13:08 AM
Old 05-21-2012
Years and years ago I worked for a small ISP (Internet Service Provider) that offered Unix (SunOS) shell accounts. In order to prevent the installation of rootkits and such, we would read-only mount as many partitions as possible, including /usr and /sbin. Not only were they mounted read-only, but they were mounted from a separate disk drive that was set via a jumper to be read-only! (Actually, we carefully soldered wires to the pins and ran them to a switch, so that we could install software updates w/o disassembling the box.)

A couple of times over the decade or so that I worked there we had someone who (as best as I could tell) got a root shell, tried to install some kind of rootkit/backdoor, found that the executables they wanted to over-write were in a r/o partition, edited the fstab to mount the partition read-write, and rebooted in the hopes of (I assume) logging in again with the ability to over-write stuff. The r/o drive would make the box cyclicly reboot until we found it.

In various log files I'd see the error you list in your initial post. If you aren't the admin for the machine you need to consult with that person.
 

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CHOWN(3)								 1								  CHOWN(3)

chown - Changes file owner

SYNOPSIS
bool chown (string $filename, mixed $user) DESCRIPTION
Attempts to change the owner of the file $filename to user $user. Only the superuser may change the owner of a file. PARAMETERS
o $filename - Path to the file. o $user - A user name or number. RETURN VALUES
Returns TRUE on success or FALSE on failure. EXAMPLES
Example #1 Simple chown(3) usage <?php // File name and username to use $file_name= "foo.php"; $path = "/home/sites/php.net/public_html/sandbox/" . $file_name ; $user_name = "root"; // Set the user chown($path, $user_name); // Check the result $stat = stat($path); print_r(posix_getpwuid($stat['uid'])); ?> The above example will output something similar to: Array ( [name] => root [passwd] => x [uid] => 0 [gid] => 0 [gecos] => root [dir] => /root [shell] => /bin/bash ) NOTES
Note This function will not work on remote files as the file to be examined must be accessible via the server's filesystem. Note When safe mode is enabled, PHP checks whether the files or directories being operated upon have the same UID (owner) as the script that is being executed. SEE ALSO
chmod(3), chgrp(3). PHP Documentation Group CHOWN(3)
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