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posix_setgid

(PHP 4, PHP 5)

posix_setgidSet the GID of the current process

Description

bool posix_setgid ( int $gid )

Set the real group ID of the current process. This is a privileged function and needs appropriate privileges (usually root) on the system to be able to perform this function. The appropriate order of function calls is posix_setgid() first, posix_setuid() last.

Note:

If the caller is a super user, this will also set the effective group id.

Parameters

gid

The group id.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #1 posix_setgid() example

This example will print out the effective group id, once it is changed.

<?php
echo 'My real group id is '.posix_getgid(); //20
posix_setgid(40);
echo 
'My real group id is '.posix_getgid(); //40
echo 'My effective group id is '.posix_getegid(); //40
?>

See Also

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User Contributed Notes 1 note

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jac
3 years ago
if you're going to use this along with posix_setuid, make sure you call posix_setgid first:

<?php
define
(PROC_USER, 'john');
define (PROC_GRP, 'admins');
?>

following works:

<?php
$user
= posix_getpwnam( PROC_USER );
$group = posix_getgrnam( PROC_GRP);

echo
posix_getuid()."\n";
echo
posix_getgid()."\n";

posix_setgid($group['gid']);
posix_setuid($user['uid']);

echo
posix_getuid()."\n";
echo
posix_getgid()."\n";
?>

following will not set gid

<?php
$user
= posix_getpwnam( PROC_USER );
$group = posix_getgrnam( PROC_GRP);

echo
posix_getuid()."\n";
echo
posix_getgid()."\n";

posix_setuid($user['uid']);
posix_setgid($group['gid']);

echo
posix_getuid()."\n";
echo
posix_getgid()."\n";
?>
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