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proc_open (PHP 4 >= 4.3.0, PHP 5) proc_open --
Execute a command and open file pointers for input/output
Descriptionresource proc_open ( string cmd, array descriptorspec, array &pipes [, string cwd [, array env [, array other_options]]] )
proc_open() is similar to popen()
but provides a much greater degree of control over the program execution.
PHP 5 introduces pty support for systems with Unix98 ptys. This allows
your script to interact with applications that expect to be talking to a
terminal. A pty works like a pipe, but is bi-directional, so there is no
need to specify a read/write mode. The example below shows how to use a
pty; note that you don't have to have all descriptors talking to a pty.
Also note that only one pty is created, even though pty is specified 3
times. In a future version of PHP, it might be possible to do more than
just read and write to the pty.
Parameters
- cmd
The command to execute
- descriptorspec
An indexed array where the key represents the descriptor number and the
value represents how PHP will pass that descriptor to the child
process. 0 is stdin, 1 is stdout, while 2 is stderr.
The currently supported pipe types are file,
pipe and pty.
The file descriptor numbers are not limited to 0, 1 and 2 - you may
specify any valid file descriptor number and it will be passed to the
child process. This allows your script to interoperate with other
scripts that run as "co-processes". In particular, this is useful for
passing passphrases to programs like PGP, GPG and openssl in a more
secure manner. It is also useful for reading status information
provided by those programs on auxiliary file descriptors.
- pipes
Will be set to an indexed array of file pointers that correspond to
PHP's end of any pipes that are created.
- cwd
The initial working dir for the command. This must be an
absolute directory path, or NULL
if you want to use the default value (the working dir of the current
PHP process)
- env
An array with the environment variables for the command that will be
run, or NULL to use the same environment as the current PHP process
- other_options
Allows you to specify additional options. Currently only
suppress_errors is supported, which suppresses
errors generated by this function when it's set to TRUE
Return Values
Returns a resource representing the process, which should be freed using
proc_close() when you are finished with it. On failure
returns FALSE.
Examples
Example 1. A proc_open() example <?php
$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", "/tmp/error-output.txt", "a") // stderr is a file to write to
);
$cwd = '/tmp';
$env = array('some_option' => 'aeiou');
$process = proc_open('php', $descriptorspec, $pipes, $cwd, $env);
if (is_resource($process)) {
// $pipes now looks like this:
// 0 => writeable handle connected to child stdin
// 1 => readable handle connected to child stdout
// Any error output will be appended to /tmp/error-output.txt
fwrite($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";
}
?> |
The above example will output
something similar to: Array
(
[some_option] => aeiou
[PWD] => /tmp
[SHLVL] => 1
[_] => /usr/local/bin/php
)
command returned 0 |
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Example 2. ptys usage <?php
// Create a pseudo terminal for the child process
$descriptorspec = array(
0 => array("pty"),
1 => array("pty"),
2 => array("pty")
);
$process = proc_open("cvs -d:pserver:cvsread@cvs.php.net:/repository login", $descriptorspec, $pipes);
if (is_resource($process)) {
// work with it here
}
?> |
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NotesNote:
Windows compatibility: Descriptors beyond 2 (stderr) are made available to
the child process as inheritable handles, but since the Windows
architecture does not associate file descriptor numbers with low-level
handles, the child process does not (yet) have a means of accessing those
handles. Stdin, stdout and stderr work as expected.
Note:
If you only need a uni-directional (one-way) process pipe, use
popen() instead, as it is much easier to use.
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proc_nice
