Displaying Errors in online c compiler - php

Hi all I have a c compiler up and running shows the output but the problem is that it dosen't show errors....
shell_exec("gcc xyz.c -o ab.out ");
$output=exec("./ab.out");
echo $output;
So it is showing output but not any errors occurred while compiling.
Any help is duly appreciated.
Thanks in advance.

Any error output from the command you run will go to STDERR and none of the exec, shell_exec functions will provide you that. One way is to redirect it
exec("gcc test.c 2>&1", $out);
The most cleaner way is to use proc_open function.
$descriptorspec = array(
1 => array("pipe", "w"), // stdout
2 => array("pipe", "w") // stderr
);
$process = proc_open('gcc test.c', $descriptorspec, $pipes);
if (is_resource($process)) {
$stderr = stream_get_contents($pipes[2]);
$stdout = stream_get_contents($pipes[1]);
fclose($pipes[1]);
fclose($pipes[2]);
$return_value = proc_close($process);
}

Related

PHP - `shell_exec` not working with NMap (Windows Server)

I've been trying to figure out why I can't get NMap to give me any sort of output nor even work for that matter via PHP.
Things I've tried so far:
// this doesn't return anything because it's wrong
$output = passthru('nmap -V');
echo $output;
// this returns a negated integer value
passthru('nmap -V', $output);
echo $output;
// this doesn't return anything either
$stream = popen('C:\nmap -V', 'r');
while (!feof($stream))
{
$buffer = fread($stream, 1024);
echo $buffer;
}
pclose($stream);
// this doesn't do anything as well
$output = system('C:\nmap -V');
echo $output;
// this does nothing also...
ob_start(); // start output buffering
fpassthru('C:\nmap -V'); // flush COMPLETE output of nmap
$output = ob_get_contents(); // capture output buffer contents
ob_end_clean(); // shutdown output buffers
echo $output; // echo it
.
// okay, how about we try a 'proc_open()'?
// nope, this doesn't work either. I just get a value of "command returned -1073741515"
$descriptorspec = array(
0 => array("pipe", "r"), // stdin is a pipe that the child will read from
1 => array("pipe", "w"), // stdout is a pipe that the child will write to
2 => array("file", "errors/errors.txt", "a") // stderr is a file to write to
);
$cwd = 'errors';
$env = array('some_option' => 'aeiou');
$process = proc_open('C:/nmap -V', $descriptorspec, $pipes, $cwd, $env);
if (is_resource($process))
{
// $pipes now looks like this:
// 0 => writeable handle connected to child stdin
// 1 => readable handle connected to child stdout
// Any error output will be appended to /errors/errors.txt
fwrite($pipes[0], '<?php print_r($_ENV); ?>');
fclose($pipes[0]);
echo stream_get_contents($pipes[1]);
fclose($pipes[1]);
// It is important that you close any pipes before calling
// proc_close in order to avoid a deadlock
$return_value = proc_close($process);
echo "command returned $return_value\n";
}
And many others, but I get absolutely NOTHING back from $output. I've done a lot of Google searching too, but I still can't figure it out. Many examples also seem to be for Linux which doesn't help.
Thanks.
Okay, I get an output using this code. I will continue coding and finish the rest of the program. Thanks to 'Chris Haas' for the suggestion in using proc_open
NOTE: The directory that contains the 'errors.txt' file must have 'IIS_IUSRS' write permissions. When in doubt, check your PHP error log.
$descriptorSpec = array(
0 => array("pipe", "r"), // stdin is a pipe that the child will read from
1 => array("pipe", "w"), // stdout is a pipe that the child will write to
2 => array("file", "errors/errors.txt", "a") // stderr is a file to write to
);
$env = array('bypass_shell' => true);
$process = proc_open("NMAP.EXE -V", $descriptorSpec, $pipes, "C:\\Program Files (x86)\\NMap", $env);
if (is_resource($process))
{
// '$pipes' now looks like this:
// 0 => writeable handle connected to child stdin
// 1 => readable handle connected to child stdout
fwrite($pipes[0], '<?php print_r($_ENV); ?>');
fclose($pipes[0]);
echo stream_get_contents($pipes[1]);
fclose($pipes[1]);
// it is important that you close any pipes before calling
// proc_close in order to avoid a deadlock
$return_value = proc_close($process);
echo "<br /><br />Command Returned: $return_value\n";
}
Nmap version 7.91 ( https://nmap.org ) Platform:
i686-pc-windows-windows Compiled with: nmap-liblua-5.3.5
openssl-1.1.1h nmap-libssh2-1.9.0 nmap-libz-1.2.11 nmap-libpcre-7.6
Npcap-1.00 nmap-libdnet-1.12 ipv6 Compiled without: Available nsock
engines: iocp poll select
Command Returned: 0

Is there any way to give user input one by one to a running .exe file in php

I want to run .exe file from php. It asks for user input one by one. Is there any way I can do this.
I tried using shell_exec(), exec() but they didn't return the expected results.
I found a solution for my own query, please find the piece of code below that solved the purpose:
$descriptorspec = array(
0 => array("pipe", "r"),
1 => array("pipe", "w"),
2 => array("file", "error.txt", "a")
);
$process = proc_open('xyz.exe', $descriptorspec, $pipes);
$input1 = "1";
if (is_resource($process)) {
print fgets($pipes[1]); // this will help you read the lines
fwrite($pipes[0], $input1."\n"); // to provide input
print fgets($pipes[1]);
fclose($pipes[1]);
fclose($pipes[0]);
$return_value = proc_close($process);
echo "command returned $return_value\n";
} else {
echo "Resource unavailable";
}

php -> fwrite to process pipe hangs -> why?

Can anyone say, why the following code hangs on fwrite($pipes[0], $data);, but it does not hang when I change $bytesCount to, for example, 1000?
I was not able to find answer via google :(
Thank you.
$descriptorspec = array(
0 => array("pipe", "r"),
1 => array("pipe", "w")
);
$bytesCount = 1000000;
$process = proc_open('cat', $descriptorspec, $pipes);
$data = str_repeat('a', $bytesCount);
fwrite($pipes[0], $data);
fclose($pipes[0]);
$response = stream_get_contents($pipes[1]);
fclose($pipes[1]);
$return_value = proc_close($process);
Pipes are implemented with input and output buffers. cat starts to read, and copies everything to the output. When the output buffer is full, its write is blocked.
Since nothing is reading cat's input (as that line is never reached), it will block indefinitely, blocking your fwrite.

Get full error from PDFTK when using PHP exec

I'm using PHP exec() in a script to merge PDF files with PDFTK.
From PHP docs: exec function says the second argument, if provided, will list each line from the console output. All I get is an empty array though.
Example of code being used:
exec(pdftk "file1.pdf" "file2.pdf" Merged_File.pdf, $output = array(), $result);
I can successfully get errors if I run the code in the console, but I'd like for my application to have access to the full text errors.
You are probably looking to get messages from stderr using proc_open. Something like this:
<?php
$cmd = "/path/to/script arguments here";
$cwd = dirname(__FILE__);
$descriptorspec = array(
0 => array("pipe", "r"), // stdin
1 => array("pipe", "w"), // stdout
2 => array("pipe", "w"), // stderr
);
if ( ($process = proc_open($cmd, $descriptorspec, $pipes, $cwd, null)) !== false )
{
// Standard output
$stdout = stream_get_contents($pipes[1]);
fclose($pipes[1]);
// Errors
$stderr = stream_get_contents($pipes[2]);
fclose($pipes[2]);
proc_close($process);
}
?>

PHP SVN update - TortoiseSVN

New code:
<?php
exec('"C:\Program Files\TortoiseSVN\bin\svn.exe" update "c:\wamp\www\project"');
This results in an infinite loop, no result is returned. What am I doing wrong?
== edit ==
On Windows, I'm trying to update a project by using PHP. I'm having problems using the commandline: I want visual feedback (important in case of conflicts), so I don't want to start as a background process. Is this possible?
The code I have so far is:
<?php
$todo = "cd \"C:\\Program Files\\TortoiseSVN\\bin\\\"";
$todo2 = "START TortoiseProc.exe /command:update /path:\"C:\\wamp\\www\\project\\\" /closeonend:0";
pclose(popen($todo, "r"));
pclose(popen($todo2, "r"));
I would drop exec and use proc_open (see http://php.net/manual/en/function.proc-open.php)
Here's an example I quickly whipped up and which should work for you:
<?php
// setup pipes that you'll use
$descriptorspec = array(
0 => array("pipe", "r"), // stdin
1 => array("pipe", "w"), // stdout
2 => array("pipe", "w") // stderr
);
// call your process
$process = proc_open('"C:\Program Files\TortoiseSVN\bin\svn.exe" update "c:\wamp\www\project"',
$descriptorspec,
$pipes);
// if process is called, pipe data to variables which can later be processed.
if(is_resource($process))
{
$stdin = stream_get_contents($pipes[0]);
$stdout = stream_get_contents($pipes[1]);
$stderr = stream_get_contents($pipes[2]);
fclose($pipes[0]);
fclose($pipes[1]);
fclose($pipes[2]);
$return_value = proc_close($process);
}
// Now it's up to you what you want to do with the data you've got.
// Remember that this is merely an example, you'll probably want to
// modify the output handling to your own likings...
header('Content-Type: text/plain; charset=UTF-8');
// check if there was an error, if not - dump the data
if($return_value === -1)
{
echo('The termination status of the process indicates an error.'."\r\n");
}
echo('---------------------------------'."\r\n".'STDIN contains:'."\r\n");
echo($stdin);
echo('---------------------------------'."\r\n".'STDOUTcontains:'."\r\n");
echo($stdout);
echo('---------------------------------'."\r\n".'STDERR contains:'."\r\n");
echo($stderr);
?>
Aside:
The line
// call your process
$process = proc_open('"C:\Program Files\TortoiseSVN\bin\svn.exe" update "c:\wamp\www\project"',
$descriptorspec,
$pipes);
could also be escaped like this
// call your process
$process = proc_open("\"C:\\Program Files\\TortoiseSVN\\bin\\svn.exe\" update \"c:\\wamp\\www\\project\"",
$descriptorspec,
$pipes);
which might or might not solve some problems on some systems that have hickups with the single brackets (') and spaces () in the notation.

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