Re: [PHP] exec and system do not work

Ethan,
A return code of not 0 means an error occured.
Probably /var/www is not writable. Test that one by doing this:
$a = is_writable("/var/www);
var_dump($a);
If that says anything else than (boolean) TRUE, you can't write in the directory. 


Sincerely,

Jasper Kips


Op 27 aug. 2013, om 02:32 heeft "Ethan Rosenberg, PhD" <[email protected]> het volgende geschreven:

> 
> 
> Ethan Rosenberg, PhD
> /Pres/CEO/
> *Hygeia Biomedical Research, Inc*
> 2 Cameo Ridge Road
> Monsey, NY 10952
> T: 845 352-3908
> F: 845 352-7566
> [email protected]
> 
> On 08/26/2013 07:33 PM, David Robley wrote:
>> Ethan Rosenberg wrote:
>> 
>>> 
>>> On 08/26/2013 11:36 AM, [email protected] wrote:
>>>> 
>>>> 
>>>>> Tamara Temple <[email protected]> hat am 26. August 2013 um 08:33
>>>>> geschrieben:
>>>>> 
>>>>> 
>>>>> 
>>>>> On Aug 25, 2013, at 10:41 PM, Ethan Rosenberg
>>>>> <[email protected]> wrote:
>>>>> 
>>>>>> Dear List -
>>>>>> 
>>>>>> I'm lost on this one -
>>>>>> 
>>>>>> This works -
>>>>>> 
>>>>>> $out = system("ls -l ",$retvals);
>>>>>> printf("%s", $out);
>>>>>> 
>>>>>> This does -
>>>>>> 
>>>>>> echo exec("ls -l");
>>>> 
>>>> Please show the output of the directory listing.
>>>> Please us "ls -la"
>>>> 
>>>>>> 
>>>>>> This does not -
>>>>>> 
>>>>>> if( !file_exists("/var/www/orders.txt"));
>>>>>> {
>>>>>>     $out = system("touch /var/www/orders.txt", $ret);
>>>> 
>>>> Maybe you don't have write permissions on the folder?
>>>> 
>>>>>>     $out2 = system("chmod 766 /var/www/orders.txt", $ret);
>>>>>>     echo 'file2<br />';
>>>>>>     echo file_exists("/var/www/orders.txt");
>>>>>> }
>>>>>> 
>>>>>> and this does not -
>>>>>> 
>>>>>> if( !file_exists("/var/www/orders.txt"));
>>>>>> {
>>>>>>     exec("touch /var/www/orders.txt");
>>>>>>     exec("chmod 766 /var/www/orders.txt");
>>>>>>     echo 'file2<br />';
>>>>>>     echo file_exists("/var/www/orders.txt");
>>>>>> }
>>>>>> 
>>>>>> Ethan
>>>>>> 
>>>>>> 
>>>>> 
>>>>> When you say "does not work", can you show what is actually not working?
>>>>> I believe the exec and system functions are likely working just fine,
>>>>> but that the commands you've passed to them may not be.
>>>>> 
>>>>> 
>>>>> 
>>>> --
>>>> Marco Behnke
>>>> Dipl. Informatiker (FH), SAE Audio Engineer Diploma
>>>> Zend Certified Engineer PHP 5.3
>>>> 
>>>> Tel.: 0174 / 9722336
>>>> e-Mail: [email protected]
>>>> 
>>>> Softwaretechnik Behnke
>>>> Heinrich-Heine-Str. 7D
>>>> 21218 Seevetal
>>>> 
>>>> http://www.behnke.biz
>>>> 
>>> 
>>> Tamara -
>>> 
>>>  > Please show the output of the directory listing.
>>>  > Please us "ls -la"
>>> 
>>> echo exec('ls -la orders.txt');
>>> 
>>> -rw-rw-rw- 1 ethan ethan 43 Aug 25 23:50 orders.txt
>>> 
>>> 
>>> Maybe you don't have write permissions on the folder?
>>> 
>>> If I perform the touch and chmod from the command line, everything works.
>>> 
>>> 
>>>  >> When you say "does not work", can you show what is actually not
>>> working? I
>>>  >> believe the exec and system functions are likely working just fine,
>>> but that
>>>  >> the commands you've passed to them may not be.
>>> 
>>> Here are my commands.
>>> 
>>> if( !file_exists("/var/www/orders.txt"));
>>> {
>>> echo system("touch /var/www/orders.txt", $ret);
>>> echo system("chmod 766 /var/www/orders.txt", $ret);
>>> echo 'file2<br />';
>>> echo file_exists("/var/www/orders.txt");
>>> }
>>> 
>>> If I now try a ls from the command line, the return is
>>>   cannot access /var/www/orders.txt: No such file or directory
>>> 
>>> The ls -la  works because the file was created from the command line.
>>> 
>>> TIA
>>> 
>>> Ethan
>> 
>> Note that touch and chmod don't return any output, so echoing the result of
>> a system call for those commands will give an empty string.
>> 
>> You should be checking the values of $ret for each execution of system to
>> see whether the command was successful or not - the return status of the
>> executed command will be written to this variable. I'd guess that touch is
>> returning 13 - permission denied.
>> 
>> if( !file_exists("/var/www/orders.txt"))
>> {
>>   system("touch /var/www/orders.txt", $ret1);
>>   echo 'touch returned '.$ret1.'<br> /';
>>   system("chmod 766 /var/www/orders.txt", $ret2);
>>   echo 'chmod returned ' .$ret2.'<br> /';
>>   echo 'file2<br />';
>> echo file_exists("/var/www/orders.txt"); }
>> 
>> Check the permissions for directory /var/www; you'll probably find it is
>> writable by the user you log on as, but not by the user that apache/php runs
>> as, which is often www - a user with limited privileges.
>> 
>> As other(s) have pointed out, there are php functions to do what you want
>> without introducing the possible insecurities involved with system et al.
>> 
> 
> David -
> 
> touch returned 1
> /chmod returned 1
> 
> rosenberg:/var/www# ls orders.txt
> ls: cannot access orders.txt: No such file or directory
> 
> rosenberg:/var# ls -ld www
> drwxr-xr-x 37 ethan ethan 20480 Aug 26 20:15 www
> 
> TIA
> 
> Ethan
> 
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