PHP shell_exec() not executing -- no errors - php

I created this DB Copy tool for my company, and everything is completely functional locally. I rsync'ed it to our tool server and now it seems it is unable to execute the shell command I'm passing with shell_exec.
$command = "/usr/bin/mysqldump -v -u$dbUser -p$dbPass ";
$command .= "-h$sourceHost -P$sourcePort $sourceDB 2>../data/dump.log ";
$command .= "| /usr/bin/mysql -u$dbUser -p$dbPass ";
$command .= "-h$targetHost -P$targetPort $targetDB 2>../data/error.log";
$output = shell_exec($command);
I capture the stderr output of the mysql dump, because that is actually used by mysqldump to show progress (dumping this table, dumping this table etc) and I read from that file on my page to show progress.
Neither of the files specified are even being created. This makes me think there is some sort of permissions issue. However I can see that my directories all have the same permissions as others on this server for working tools. Doesn't rule it out, but I'm not sure what to assess further.
I tried changing shell_exec() to exec() and adding a variable to capture the output ( exec($command, $shellOutput) ) and $shellOutput was empty.
I echo'd the command to be run, after it is formed by the script, and was able to run that on the server with no issues.
I'm a bit at a loss here, as it's not even giving me any feedback to work with. Any ideas on what I can try?
To add context, this is a page that is being called by $.ajax to kick off this dump. After this shell command, there is an echo of what db was copied, and that is returning. So the page is being called correctly, it seems to only be the shell command itself that is simply not working.
Thanks in advance.
*Also worth noting that our directory structure is such that our www folder of our project is symlinked to the documentRoot of the server.

You can try system("ur command 2>&1");
This should work and if not output why it doesn't work.

Am sure its to do with your permissions
ls -ld directory
If thats the problem change mode chmod to your preference

Etan had it correct. It was something new to me that the files are created before anything it run (but it makes complete sense). I took the files out, and the command ran. I ended up having to give apache permission to write to the data directory in my project.
Still wrapping my head around linux permissions.
Thanks all.

Related

why is my "at job" not executing my php script when created through a php webpage?

$output = shell_exec('echo "php '.$realFile.'" | at '.$targTime.' '.$targDate.' 2>&1');
print $output;
Can someone please help me figure out why the above line isn't doing what it's supposed to be doing? The idea is for it to create an 'at' job that will execute a php script. If I switch to the user apache(which will ideally control the at function when the php file is complete) I can run
echo "php $realFile.php" | at 00:00 05/30/17
and it'll do EXACTLY what I want. The problem is in the above snippet from my php file it will not create the at job correctly. when I do a at -c job# on both of them the job made from my file is about a 3rd the length missing the User info and everything. It basically starts at PATH= and goes down. Doesn't include HOSTNAME=, SHELL=, SSH_CLIENT=, SSH_TTY=, USER=. I assume it needs most of this info to run correctly. The end output (below)is always the same though it just doesn't have any of the top part for some reason. Let me know if you need more info. I didn't want to paste all of my code here as it contains job specific information.
${SHELL:-/bin/sh} << 'marcinDELIMITER0e4bb3e8'
php "$realFile".php
marcinDELIMITER0e4bb3e8
It doesn't seem to be a permission issue because I can su to apache and run the exact command needed. The folder the files are located in are also owned by apache. I've also resulted to giving each file I try to run 777 or 755 permissions through chmod so I don't think that's the issue.
I figured out a coupe ways around it a while back. The way I'm using right now is an ssh2 connect to my own server as root and creating it that way. No compromise as you have to enter the password manually each time. Really bad work around. The main issue is that apache doesn't have the correct permissions to do everything needed for the AT job so someone figuring that out would be awesome. Another option I found on a random webpage would be to use sudo through the php script, but basically the same minus having to reconnect to your own server. Any other options would be appreciated.
Reading the manual and logs would be a good place to start. In particular:
The value of the SHELL environment variable at the time of at invocation will determine which shell is used to execute the at job commands. If SHELL is unset when at is invoked, the user’s login shell will be used; otherwise, if SHELL is set when at is invoked, it must contain the path of a shell interpreter executable that will be used to run the commands at the specified time.
Other things to check are that the user is included in at.allow, SELinux is disabled and the webserver is not running chrrot.

Running shell script from webserver

I have a shell script named brew.sh as follows:
#!/bin/bash
brew doctor > test.txt
Which works fine when I run it from the command line. It outputs as expected the output of brew doctor to the test.txt file. However, when I call it from a php webpage as below it creates the test.txt file but the file is empty.
<?php
$output = shell_exec("./brew.sh");
echo $output;
?>
I suspected it was a permissions/ownership issue so I used chown to change ownership from username:staff to _www:_www on the parent directory,where it would then create the test.txt file but not write the output to it. I've even tried changing permissions to 777 temporarily on the test.txt and even that didn't work. Ultimately I would like to view the output of brew doctor and brew update on a webpage on my local development machine. Surely it shouldn't be that difficult?
Elias is going to be right I suspect - your environment on the cmd line is not going to be like the environment the script finds itself in within the webserver, assuming the webserver user is even allowed to run a proper shell...
You'll need a path. Check what your path value is, and put it in.
Also doesn't hurt to always include the full path for your binary, i.e. brew.
#!/bin/bash
PATH="/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin"
/usr/local/bin/brew doctor > /var/www/whatever/test.txt
.... personally.. This isn't the approach I would use. If this is for brew doctor and brew update I would just use cron jobs that redirect output to a file on the webserver since I wouldn't want the webserver invoking brew commands... someone could DoS the server pretty easily just by requesting those pages a lot. The cron solution is pretty bulletproof though - and in any case with cron I can run it as a more appropriate user where the permissions/environment for brew are likely to work more correctly in any case.
Also - the other guys point about checking errors is a good one. stderr is probably ending up in your web logs at the moment when you get empty output. 2>&1 can make it go into that file instead, probably.
[ Note that it has to be 2>&1 !! I think chris had a typo when he wrote >2&1 which does something very different. 2 is the stderr filehandle which we want to redirect to 1. >2 will redirect 1 (stdout) to a file called 2.
If you add 2>&1 to your shell command, you should get STDERR and STDOUT returned which will at least help you determine what is going on:
<?php
$output = shell_exec("./brew.sh >2&1");
echo $output;
?>

PHP exec(psexec.exe) hangs indefinitely

I have a development / testing setup on a windows box and need to test calling a background process. I am using http://www.somacon.com/p395.php as a list of options for running a background service.
Here is the sample code I am trying to run:
$string = "PsExec.exe -d cmd /c \"mspaint\"";
echo $string;
exec($string, $data);
This works when I type it into the command line.
I haven't attempted to do a lot of exec's on Windows, but it would be nice to be able to test it locally before moving to a Linux box.
Right now, I am thinking it has something to do with the fact that psexec opens a new window? I don't know how to fix that, however.
There are no apache or PHP error logs being generated, the page just never stops. This also seems to override PHP's max execution time.
EDIT:
This is not fully correct answer. The command psexec \\machine cmd.exe /C 1 & dir won't hang because psexec first return saying that command 1 doesn't exists in remote machine and then dir is evaluated in the local machine. I got tricked by cmd operator order. The & operator is being invoked in the local cmd.exe process, not the remote one. But the logic still applies if you quote the command: psexec \\machine cmd.exe /C "1 & dir".
Original Answer:
There is something strange going on while invoking psexec within PHP in windows. No matter if you are using shell_exec(), exec(), popen() or proc_open(). It will hang anyway.
Honestly I don't know what's going on, you could also download PsExplorer in order to trace your process command line, arguments, etc. You'll find this tool very useful.
I'm using XAMPP on Windows, and after certain tests I found this:
First of all create a test file (i.e. test.php) and place it in your web server so you can access it with this content:
<?php
echo "<pre>".shell_exec("psexec \\\\machine <options> cmd.exe /C dir")."</pre>";
?>
Note that you could use GET arguments in order to create a more flexible example. To debunk that this indeed is working before you test over a webpage, issue the command php <path-to-the-file>\test.php. That will work perfectly. But, it won't work on a web browser.
If you kill the process, you'll get the first line: El volumen de la unidad C no tiene etiqueta.. Next line, in my language there's an accent included so I thought It could be encoding (or code pages) issues. So instead of cmd.exe /C dir I tested cmd.exe /C chcp 850 && dir. That, for my surprise, works.
Then, I realize that no matter what command you set before it will also work, for instance, cmd.exe /C 123 & dir (note the single & as I'm not evaluating the command output).
Honestly, I don't know what is going on with psexec and PHP via web browser. More surprisingly, commands like cmd.exe /C copy cmd.exe cmd.exe.deleteme and cmd.exe /C mkdir deletethis will work!
So, you could give it a try to cmd.exe /C 1 & \"mspaint\" as your problem and my seems similars. For single commands could be a workaround but I'm developing an unattended framework for installing software and all my files are .cmd or .exe or .bat files.
Let me know If you found something interesting :)
I have a solution!
This topic is old but still relevant. I wanted to use PsExec 2.2 with PHP 7.2.0 RC3 to execute a script remotely. I need the output of the script and so i was using PsExec.exe -accepteula \\HOST -u xxx -p xxx with >> LOGFILE 2>&1.
Because I dont want to wait the script to finish, I used exec() like this: exec('start /p cmd /c PsExec.exe -accepteula \\HOST -u xxx -p xxx >> LOGFILE 2>&1').
My php script continues working and PsExec does his job too.
Everything works fine but my LOGFILE always contains only the first line of the STDOUT output.
I have tried many solutions mentioned here, but none of them worked for me. Executing the command in the CMD directly, PsExec returns all lines of STDOUT but inside php it does not.
At the php doc for exec() I have found comments where some people used PsExec to run a programm without waiting (http://php.net/manual/de/function.exec.php#86438). As a last chance I tried the following: exec('PsExec.exe -accepteula -i -d cmd /c PsExec.exe -accepteula \\HOST -u xxx -p xxx >> LOGFILE 2>&1')... And it works!
PsExec now returns everthing into my LOGFILE. I hope I could help you and save you some time.
My current solution was to use WScript.Shell:
$string = "cmd /c \"cd {$full_base}{$newSource} && ant release > compile.txt\"";
$Shell = new COM("WScript.Shell");
$exec = $Shell->Run($string, 0, false);
Not sure if this was definitively answered or not, but I was having the same problem with PSEXEC hanging, though in my case, on some machines it did, and others it didn't. It turned out to be accepting the EULA. On machines that I'd run it from a command line and used the same username/password as my PHP script, it ran without hanging.
Further research showed that I could specify the EULA acceptance by including it in the command being executed from PHP:
This DID hang: psexec \\MACHINENAME ...
This did NOT: psexec /accepteula \\MACHINENAME ...
ok here are the things. I also jumped into similar condition as you were and hopefully since i am commenting this late you must have figured out a way too .But for those who are still in this problem , i suggest them few tips .
1)The code that has been posted is super fine , no problem with that thing. If your page hangs out infinitely then try to add -i -d params before the source exe. (see the documentation HERE ). You can also add -accepteula (EULA) flag in the command to let the page load and not to wait for that command to finish(solves the infinite wait problem).
2)For me these things didnt work . It doesnt mean that you guys dont try these things .these are the first steps if your code starts working then thats fine for you.Else ,make another account as an adminstrative one ,type services.msc in the start menu , you will see the page there. Search for wampapache or xammp services ,excluding mysqld one. Then simply click on that service .GO to log on tab ,select This account .Select the previously made admin acc , type its password if you set that else leave the textbox empty.Type the name of that account as \\accname at the name field . If u dont know the account name ,Click to Browse->Advanced->FInd now you will see that name account . Select, apply settings and restart the wamp app and you are good to go :)
Also make sure to double check the string you feed into your exec command. Seems trivial, but had me stumped for awhile. In many cases PHP escapes the double backslash in your machine address which throws everything off. To get around this, create your string like:
$string = 'PSExec /accepteula \\\\MACHINENAME ...'

Can I rip DVDs from a local web app with HandBrake?

I'm building a PHP web application that will run on my machine, and one of its purposes is to call HandBrakeCLI with an exec() or similar call. If I run the command
HandBrakeCLI -i path_to_dvd_drive -o output_file --preset preset_name
from a shell, it works fine. However, when I put the exact same command in an exec() php function (or similar), it doesn't work, and doesn't return anything, aside from a return status of 0. No errors, nothing else.
Is this just a simple permissions issue that I'm not seeing, due to the lack of errors being spit out? Or am I missing something else?
For debugging, try running the command from the console but as the user PHP runs as. Here are some pointers how to find out which user that is.
Then use sudo to run the command as the Apache user. You will probably get more helpful information from that.
try to exec your script using absolute path (type which HandBrakeCLI in terminal to find it) and append 2>&1 to the end of command, like:
exec('HandBrakeCLI -i path_to_dvd_drive -o output_file --preset preset_name 2>&1')
this way if command outputs anything to stderr you will see it.
is handbrake in the path of whatever shell PHP is invoking when it does the exec()? Does whatever account PHP/webserver is running under have access to the directory where handbrak.exe is, and have permission to execute handbrake.exe? Does the webserver account have permissions to access the dvd drive, etc...
Many things to check, and without better diagnostic information, this is about the best you'll be able to get here.

run shell script from php

I am attempting to create a php script that can connect thru ssh to my Qnap TS219 server and run a command on it.
My script so far connects fine to the server but when I run the command I get an error message and I can't figure it out.
exec.sh
#!/bin/bash
cp /share/MD0_DATA/Qdownload/rapidshare/admin/script.txt /share/MD0_DATA/Qdownload/rapidshare/admin/script.sh
chmod 755 /share/MD0_DATA/Qdownload/rapidshare/admin/script.sh
nohup sh /share/MD0_DATA/Qdownload/rapidshare/admin/script.sh &
exit 0
script.sh
#!/bin/bash
/opt/bin/plowdown -o /share/MD0_DATA/Qdownload/rapidshare /share/MD0_DATA/Qdownload/rapidshare/admin/down.txt 2>/share/MD0_DATA/Qdownload/rapidshare/admin/output.txt
the command that I am currently running thru ssh after I submit the form:
echo $ssh->exec('sh /share/MD0_DATA/Qdownload/rapidshare/admin/exec.sh');
Right now generates the code below but only after I kill 2 bash processes (the page keeps loading indefinetly and the processor activity is at 100% if I don't kill the 2 bash processes):
/share/MD0_DATA/.qpkg/Optware/share/plowshare/lib.sh: line 261: getopt: command not found start download (rapidshare): http://rapidshare.com/files/312885386/Free_Stuff-Your_Internet_eBay_Business_Free_Startup_Resources.rar /share/MD0_DATA/.qpkg/Optware/share/plowshare/lib.sh: line 261: getopt: command not found /share/MD0_DATA/.qpkg/Optware/share/plowshare/lib.sh: line 46: --insecure: command not found Error: failed inside rapidshare_download()
This script will be used in my local network, no access from outside, so I am not worry about security, I know the code looks very basic, primitive but I have no experience with php, shell script, so if someone can make any sense on this and help me out will be greatly appreciated.
Edit1. I also tried the shell_exec command still no joy and if I run the script thru putty works beautifully.
Edit2. I think we are on to something.
I added the code you suggested and I got the following message.
sh: /share/MD0_DATA/.qpkg/Optware/share/plowshare: is a directory /usr/bin:/bin:/usr/sbin:/sbin
I think at the moment the PATH is usr/bin:/bin:usr/sbin:/sbin and I think it should be /opt/bin /opt/sbin because there are the "executables". Any ideeas?
Thanks,
Chris.
Run this
echo $ssh->exec('pwd');
Does it list your path correctly? If so then your problem is NOT PHP, if it doesn't list or still gives an error then PHP is your problem and we can continue from there.
From the error you've listed, my first guess would be that PATH isn't set, so lib.sh can't find what it's looking for.
Remember you're logging in with a custom shell (PHP ssh), quite often things aren't set as they should be, so your scripts might not find requirements like paths and variables.
Edit:
Since it's giving /root, we at least know it's going through, why not also set the PATH etc...
echo $ssh->exec('PATH=$PATH;/share/MD0_DATA/.qpkg/Optware/share/plowshare; sh /share/MD0_DATA/Qdownload/rapidshare/admin/exec.sh');
Remember you can also use this to see what is and isn't being set.
echo $ssh->exec('ECHO $PATH');
I think I got it:
Following viper_sb logic, I changed the code to:
echo $ssh->exec('PATH=$PATH:/share/MD0_DATA/.qpkg/Optware/bin; sh /share/MD0_DATA/Qdownload/rapidshare/admin/exec.sh');
echo $ssh->exec('echo $PATH');
and magic, it worked ... I'll test it further, when I get home, but I think it worked, a file was downloaded in the /Qdownload/rapidshare folder ... hooray.

Categories