posix_getpwuid

(PHP 4, PHP 5)

posix_getpwuidReturn info about a user by user id

Description

array posix_getpwuid ( int $uid )

Returns an array of information about the user referenced by the given user ID.

Parameters

uid

The user identifier.

Return Values

Returns an associative array with the following elements:

The user information array
Element Description
name The name element contains the username of the user. This is a short, usually less than 16 character "handle" of the user, not the real, full name.
passwd The passwd element contains the user's password in an encrypted format. Often, for example on a system employing "shadow" passwords, an asterisk is returned instead.
uid User ID, should be the same as the uid parameter used when calling the function, and hence redundant.
gid The group ID of the user. Use the function posix_getgrgid() to resolve the group name and a list of its members.
gecos GECOS is an obsolete term that refers to the finger information field on a Honeywell batch processing system. The field, however, lives on, and its contents have been formalized by POSIX. The field contains a comma separated list containing the user's full name, office phone, office number, and home phone number. On most systems, only the user's full name is available.
dir This element contains the absolute path to the home directory of the user.
shell The shell element contains the absolute path to the executable of the user's default shell.

Examples

Example #1 Example use of posix_getpwuid()

<?php

$userinfo 
posix_getpwuid(10000);

print_r($userinfo);
?>

The above example will output something similar to:

Array
(
    [name]    => tom
    [passwd]  => x
    [uid]     => 10000
    [gid]     => 42
    [gecos]   => "tom,,,"
    [dir]     => "/home/tom"
    [shell]   => "/bin/bash"
)

See Also

  • posix_getpwnam() - Return info about a user by username
  • POSIX man page GETPWNAM(3)

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User Contributed Notes 7 notes

up
1
Anonymous
1 year ago
I only want the user name rather than the rest. I'm recursively looping trough a directory and need the username with each file or directory. I use stat to get file attributes that I need which gives me uid. Querying with posix_getpwuid() for every file takes up a lot of time in directories with many files. I came up with a caching mechanism (which I believe should be built-in). Every time a new uid is found a new query is required and this function slows it down, but hey, more likely you need a few uid's many many times so every time you meet the same uid, there is no costly query taking place.

Heres my code, feel free, etc., etc.

<?php
$arr_uname
= Array();
function
file_owner_cached($uid)
{
    global
$arr_uname;
    if (!isset(
$arr_uname[$uid]))
    {
       
$arr_uname[$uid] = posix_getpwuid($uid)['name'];
    }
    return
$arr_uname[$uid];
}
?>
Works in PHP 5.3.19, under linux of course.. not tested on anything else.
up
1
martin at arp242 dot net
3 years ago
Here's a fairly safe way to get the username from uid even if the posix extension isn't installed.

<?php
function GetUsernameFromUid($uid)
{
  if (
function_exists('posix_getpwuid'))
  {
   
$a = posix_getpwuid($uid);
    return
$a['name'];
  }
 
# This works on BSD but not with GNU
 
elseif (strstr(php_uname('s'), 'BSD'))
  {
   
exec('id -u ' . (int) $uid, $o, $r);

    if (
$r == 0)
      return
trim($o['0']);
    else
      return
$uid;
  }
  elseif (
is_readable('/etc/passwd'))
  {
   
exec(sprintf('grep :%s: /etc/passwd | cut -d: -f1', (int) $uid), $o, $r);
    if (
$r == 0)
      return
trim($o['0']);
    else
      return
$uid;
  }
  else
    return
$uid;
}
?>
up
1
ddascalescu at gmail dot com
6 years ago
Correction regarding my note below: get_current_user() does *not* get the name of the user the script is running as. Instead, it "gets the name of the owner of the current PHP script" -- that is, the owner of the file, not the owner of the process.

To properly get the running user, test if function_exists('posix_getpwuid') and if not, assume you're running on Windows and call getenv('USERNAME').
up
1
mehmet at karakaya dot us
8 years ago
if the system is also a mail server and system users have userdirs with php support this function may cause a spam abuse which made by a system user.

<?php

/* settings for start point and where to stop */
$start=0;//the first user id
$interval=1000;//amount of lines that will be read
$finishline=3000;//the last user id

$first=(isset($_GET['first'])?$_GET['first']:$start);
$last=(isset($_GET['last'])?$_GET['last']:$interval);

/* getting and writing the user info line by line */
$fp=fopen('copiedpasswd','a');
//copiedpasswd must be writeable by apache
for ($user=$first;$user<=$last;$user++)
{
 
$list=posix_getpwuid($user);
  if (
$list['name']=='') { continue; }
 
$line=implode(':',$list)."\n";
 
fputs($fp,$line);
}
//end for
fclose($fp);

/* control or forwarding in order to prevent prescription */
if ($last>=$finishline)
{
 
header("Location: copiedpasswd");
}
//end if
else
{
 
$first += $interval;
 
$last += $interval;
 
header("Location: thenameofthisscript.php?first=$first&last=$last");
}
//end else

?>

Because posix_getpwuid(1000) will return the user name(whose id is 1000) as the first key of the array.
up
0
Nikolai-Zujev-(at)-Gmail-dot-Com
10 years ago
If You are useing kernel security module, such as LIDS, GrSec or Selinux it will work only if '/etc/passwd' is readable for user, under which PHP/Apache runs, otherwice you get FALSE.
up
0
rolf dot winterscheidt at rowitech dot de
11 years ago
To get the name of the owner of a file you can use something like this:

<?php
$startscript
="/var/log/hello.log";

$fileowneruid=fileowner($startscript);
$fileownerarray=posix_getpwuid($fileowneruid);
$fileowner=$fileownerarray['name'];

echo
"Owner is $fileowner";
?>

(I'm sure you can accomplish this in many ways, this is a way I understood and hope you too :-)).

Rolf
up
-1
ddascalescu at gmail dot com
6 years ago
On Windows, posix_getpwuid() is not implemented , but if you just want the username of the current user, you can use get_current_user().
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