setgid()

Установить реальные, эффективные и сохраненные идентификаторы групп

Прототип:

#include <unistd.h>
                                       
int setgid( gid_t gid );

Аргументы:

gid

The group ID that you want to use for the process.

Библиотека:

libc

Описание:

The setgid() function lets the calling process set the real, effective and saved group IDs, based on the following:

• If the process is the superuser, the setgid() function sets the real group ID, effective group ID and saved group ID to gid.

• If the process isn't the superuser, but gid is equal to the real group ID, setgid() sets the effective group ID to gid; the real and saved group IDs aren't changed.

This function doesn't change any supplementary group IDs of the calling process.

If you wish to change only the effective group ID, and even if you are the superuser, you should consider using the setegid() function.

The “superuser” is defined as any process with an effective user ID of 0, or an effective user ID of root.

Возвращаемое значение:

0

Успешное завершение.

-1

Возникла ошибка. Код ошибки записан в errno.

Коды ошибок:

EINVAL

The value of gid is invalid.

EPERM

The process doesn't have appropriate privileges, and gid doesn't match the real group ID.

Примеры:

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
                                       
int main( void )
{
    gid_t ogid;
                                       
    ogid = getgid();
    if ( setgid( 2 ) == -1 )
    {
        perror( "setgid" );
        return (EXIT_FAILURE);
    }
    printf( "group id is now 2, was %d\n", ogid );
        
    return (EXIT_SUCCESS);
}

Классификация:

POSIX 1003.1

Точка остановки потока

Нет

Обработчик прерываний

Нет

Обработчик сигналов

Да

В потоке

Да

Тематические ссылки:

errno, setegid(), seteuid(), setuid()

Предыдущий раздел: Описание API системной библиотеки