CentOS Linux console command versus PHP exec(command) - php

Question

I have a C program that I wrote called convert3to5, originally written for CentOS / Fedora 32bit system in early 2010. I am moving it to new CentOS 6.x 64bit system host.
From a CentOS Putty console I can run the convert3to5 command just fine; here is a sample of it running from my console:
[root#cloud convert3to5]# ls
CircleStar convert3to5 Convert3To5.txt test.tif
[root#cloud convert3to5]# ./convert3to5 /var/www/webadmin/data/www/mydomain.com/uploads/SV-DIS160217B.tif
TIFFReadDirectory: Warning, /var/www/webadmin/data/www/mydomain.com/uploads/SV-DIS160217B.tif: wrong data type 7 for "RichTIFFIPTC"; tag ignored. Image has an undefined fillorder - using default: MSB2LSB
The above is a normal completion of convert3to5 and I get a SV-DIS160217B.bmp that is placed in /var/www/webadmin/data/www/mydomain.com/uploads/ So running it from console works fine.
Question - I am attempting to run the same exact command from PHP using the exec(command, output, return) command as follows:
chdir($sv_path.$c3to5_path); //change our working directory to "/convert3to5" directory
$command = "./convert3to5 $targetFile 2>&1";
$result = exec($command, $output, $return);
// the output of the above command - is a .bmp file it will be placed in the same path as the input .tif file
I get the following $result:
ERROR: Unable to convert
/var/www/webadmin/data/www/mydomain.com/uploads/SV-DIS160217B.tif to 5
color BMP file: Open file Error: Tiff_3_to_BMP_5_.lut!
My convert3to5 does need to open Tiff_3_to_BMP_5_.lut
Why does it find Tiff_3_to_BMP_5_.lut when I run convert3to5 from a console prompt but not from PHP exec(...) in both cases my pwd shows that I am in
[root#cloud convert3to5]# pwd
/var/www/webadmin/data/www/mydomain.com/myView/convert3to5
I have also verified pwd is correct from my PHP script after the
chdir($sv_path.$c3to5_path);
Tiff_3_to_BMP_5_.lut is in CircleStar directory - the path to CircleStar is /var/www/webadmin/data/www/mydomain.com/myView/convert3to5/CircleStar
Summary: ./convert3to5 works while PHP exec('convert3to5 ..) does not appear to work.
Can anyone suggest the difference and how to fix and/or debug?
Thanks

Answer 1

You're running the console from the convert3to5 directory, and I suspect your old C program used a relative path to the .lut file, possible relative to the .tif?
What if in the console example you did
cd ../..
./path/to/convert3to5/convert3to5 /var/www/webadmin/data/www/mydomain.com/uploads/SV-DIS160217B.tif
Might be related to $targetFile. Print that and see if it's the full path.
Finally, run
/full/path/to/convert3to5 fullTargetPath
If that works, then as a workaround, if you just do exec('/full/path/to/convert3to5 $fullTargetPath, ..) it should behave like the console.

Answer 2

Per my above comment to wonton:
From the console I was running as root (so fully privileged). I supposed my PHP script will run as the "apache" user on the server?
Here was the problem I believe: I looked at the CircleStar directory privileges where the Tiff_3_to_BMP_5_.lut file exists. CircleStar had rw-r--r-- (0644) when running as root from console this allowed my convert3to5 program to find and open Tiff_3_to_BMP_5_.lut file just fine. However not the PHP exec(...) once I changed the privilege on CircleStar to rwxr-xr-x (0755) PHP exec(...) ran fine!
So ultimately it was a permission issue.