seteuid()

Set the effective user ID

Synopsis:

#include <unistd.h>

int seteuid( uid_t uid );

Since:

BlackBerry 10.0.0

Arguments:

uid
The effective user ID that you want to use for the process.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The seteuid() function lets the calling process set the effective user ID, based on the following:

  • If the process has the PROCMGR_AID_SETUID ability enabled (see procmgr_ability()), the seteuid() function sets the effective user ID to uid.
  • If the process doesn't have the PROCMGR_AID_SETUID ability enabled, but uid is equal to the real user ID or saved set-user ID, seteuid() sets the effective user ID to uid.

The real and saved user IDs aren't changed.

If a set-UID process sets its effective user ID to its real user ID, it can still set its effective user ID back to the saved set-UID.

Returns:

0
Success.
-1
An error occurred ( errno is set).

Errors:

EINVAL
The value of uid is out of range.
EPERM
The process doesn't have the PROCMGR_AID_SETUID ability enabled, and uid doesn't match the real user ID or the saved set-user ID.

Examples:

/*
 * This process sets its effective userid to 0 (root).
 */

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>

int main( void )
{
    uid_t oeuid;

    oeuid = geteuid();
    if( seteuid( 0 ) == -1 ) {
        perror( "seteuid" );
        return EXIT_FAILURE;
    }

    printf( "effective userid now 0, was %d\n",
        oeuid );

    return EXIT_SUCCESS;
}

Classification:

POSIX 1003.1

Safety:  
Cancellation point No
Interrupt handler No
Signal handler Yes
Thread Yes

Last modified: 2014-06-24



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