Why wont PHP run system commands?

Anon

Hi,

I am trying to use a PHP script to back up a directory and all its contents, but with no luck :-(

here is one way Ive being trying.

$string = system("tar -cf backup.tar /home/www/directory_name");
print "done!";

Of course it will work in Perl no problem!
#!/usr/bin/perl

system("tar -cf backup.tar //home/www/directory_name");
print "Content-type: text/html\n\n";
print "Done!";

would be grateful for any help :-)

Robert

Anon

Try pathing to tar and pathing to where you want the backup.tar to be placed. Also make sure the directories have proper access for the user that runs the web server.

$string = system("/bin/tar -cf /direcotory/with/write/privs/backup.tar /home/www/directory_name");
print "done!";

Anon

Thanks for the help Chad,

I tried what you said. I created a new directory and CHMODed it 777, but still no luck.

$string = system("/bin/tar -cf /home/www/backups/backup.tar /home/www/functions");
print "done!";

any more ideas?

thanks,
Robert

Anon

It's likely a path problem. More than likely, your web server runs as nobody, instead of a real fake id, like httpd.

The easy answer is just add the path to your command like so:

"/bin/tar -cvf yadayada"

So it can find tar.

Anon

As an FYI, I'm running the apache module of php4 on Linux-Mandrake 7.1.

With that being said, what do you get for the following things.

1) Change the script as below and see what the return status is (0 for sucess, 2 for error).
<?

$string = passthru("/bin/tar -cf /home/www/backups/backup.tar /home/www/functions", $return);
print "done! ($return)";

2) Check the web server error log for what tar is spitting out on stderr.

Anon

I tried that, still didn't work! this is what it returned.

done! (127)

(the first script returned "Done" (ie. no error msg)

I tried looking up the Apache error logs but I couldn't find any thing in them. Are there other logs I could search?

thanks
Again

Anon

Chad sujjested that, but it didn't work.v I created a new directory and CHMODed it 777 so it "should" have worked!

$string = system("/bin/tar -cf home/www/backups/backup.tar /home/www/functions");

thanks

Robert

Anon

As an fyi from the 'info tar'...

"GNU tar' returns only a few exit statuses. I'm really aiming simplicity in that area, for now. If you are not using the--compare'
(--diff',-d') option, zero means that everything went well, besides
maybe innocuous warnings. Nonzero means that something went wrong.
Right now, as of today, "nonzero" is almost always 2, except for remote
operations, where it may be 128."

I'm not sure what is meant by remote operations.

As for the error logs, on my system it is /var/log/httpd/error_log, and when playing around with your code, I got messages like this....

/bin/tar: /backup.tar: Cannot open: Permission denied
/bin/tar: Error is not recoverable: exiting now
/bin/tar: /backup.tar: Cannot open: Permission denied
/bin/tar: Error is not recoverable: exiting now
/bin/tar: Removing leading /' from member names /bin/tar: Removing leading/' from member names
/bin/tar: /backup.tar: Cannot open: Permission denied
/bin/tar: Error is not recoverable: exiting now

I'm not sure where to look other than that.

Have you tried a different command such as 'ls'?

Anon

OK, after my host upgraded to PHP $ I can now use gzcompress. But the only problem is I want to compress files, not strings.

<?
$string = "This is the string to be compressed!";
$filename = tempnam ("$base_dir"."backups/", 'test').'.gz';
$zp = gzopen($filename, "w9");
gzwrite($zp, "$string");
gzclose($zp);

but this only compress the string $string. I want the .gz file to contain 3 or 4 indivdual files.

thanks for the help.
Robert

Anon

Robert wrote:

OK, after my host upgraded to PHP $ I can now use gzcompress. But the only problem is I want to compress files, not strings.

<?
$string = "This is the string to be compressed!";
$filename = tempnam ("$base_dir"."backups/", 'test').'.gz';
$zp = gzopen($filename, "w9");
gzwrite($zp, "$string");
gzclose($zp);

but this only compress the string $string. I want the .gz file to contain 3 or 4 indivdual files.

First, if a .gz file will hold more than one file, it'll have to be in a tar file, since gz is a single file compression program.

If you want to output a .gz that has more than one file, you need to use tar to stick them together, so add this:

<code to write files out goes here. i.e. put them in a temp directory of your creation>
chdir ("that/temp/dir/i/just/mentioned");
$result=tar -cvzf /somedir/file.tar.gz .;
print "<pre>";
print $result;
print "</pre>";

Anon

Did you ever find a solution to this problem? I have the exact same problem now with my ISP.

/Lars

Anon

Yes and no. I never got PHP to work tar files (it would only tar/gzip strings). Instead I used the Perl system() command.

You could use a cobmination of PHP and Perl, use the virtual() command in a PHP file to call the Perl script.

regards,
Robert