Execution of PDFTk from PHP script is failing with error code 11

Question

I am trying to Fill in a PDF from PHP script. I am following the article by Sid Steward at the following URL.

I have configured PDFTk package on CentOS linux distribution and I am able to execute the pdftk from the command prompt and it merges the FDF form with the PDF and successfully generates the flattened(Filled) PDF. I am using following command to test the Pdftk using shell.

pdftk /tmp/form.pdf fill_form /tmp/fdfbm0pe7 output /tmp/filledform.pdf flatten

But When try to execute a similar command through PHP, I am getting the error. The passthru command is failing with error code 11. Following is the php code I am using to execute the command:

$command = 'pdftk form.pdf fill_form '. $fdf_fn. ' output - flatten';
passthru($command, $error);

The $fdf_fn above has the FDF file name. The form.pdf is the fill-able pdf form. Both the form.pdf and the PHP script file from which I have given the above lines of code are in the same folder. I have checked that PDFtk is executing correctly through PHP by echoing shell_exec('pdftk') and it was returning the standard help details.

Just to provide more details, the path to pdftk is /usr/bin/ and PHP script and PDF form files are located under /var/www/html/pdfmerge.

Can some one please guide what I am doing wrong that the command execution through PHP is failing with error code 11?

Answer 1

I had the exact same issue with PHP running PDFTK on CentOS and spent a number of hours hunting things down, so I hope someone will find this useful. My specific use for PDFTK is for the FillPDF module on Drupal. The solution to the exit code 11 issue was setting a local policy module to allow httpd to run PDFTK. If you grep /var/log/audit/audit.log for pdftk like this

grep -i pdftk /var/log/audit/audit.log

you should see some errors, probably one for 'execmem', amongst others. Here is what I did to fix the issue...

Running this command will pull the errors out of the log and put them into a file for you to review.

grep -i pdftk /var/log/audit/audit.log | audit2allow -m pdftklocal > pdftklocal.te

If the output looks good (e.g. there IS output), run this command to create the module.

grep -i pdftk /var/log/audit/audit.log | audit2allow -M pdftklocal

Once the module is created, you make the policy active by running this command.

/usr/sbin/semodule -i pdftklocal.pp

PDFTK should run now from PHP. If it does not, check to see if httpd_enable_cgi is on by running

getsebool httpd_enable_cgi

If it is not on, turn it on by running

setsebool -P httpd_enable_cgi 1

Details on the policy module can be found here: http://wiki.centos.org/HowTos/SELinux#head-faa96b3fdd922004cdb988c1989e56191c257c01

Answer 2

I had a similar issue to what you were having and it turns out that PHP didn't have access to read the .pdf, .fdf and did not have access to create the flattened .pdf file in the /tmp directory.

to see if that is the issue try doing

chmod 777 /tmp

to see if that fixes the issue. I wouldn't recommend leaving at 777 but maybe moving it back to 700 or so.