setreuid()

Set the real and effective user IDs for the calling process

Synopsis:

#include <unistd.h>

int setreuid( uit_t ruid, 
              uid_t euid );

Arguments:

ruid
The real user ID that you want to use for the process, or -1 if you don't want to change it.
euid
The effective user ID that you want to use for the process, or -1 if you don't want to change it.

Library:

libc

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

Description:

The setreuid() function sets the real and effective user IDs of the calling process. If ruid or euid is -1, the corresponding real or effective user ID isn't changed.

If the process has the PROCMGR_AID_SETUID ability enabled (see procmgr_ability() ), you can set the real user ID and the effective user ID to any legal value.

If the process doesn't have the PROCMGR_AID_SETUID ability enabled, you can set either the real user ID to the effective user ID, or the effective user ID to the saved set-user ID or the real user ID.

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.

In either case, if you're changing the real user ID (i.e. ruid is not -1), or you're changing the effective user ID to a value that isn't equal to the real user ID, the saved set-user ID is set equal to the new effective user ID.

Returns:

Zero on success, or -1 if an error occurs ( errno is set).

Errors:

EINVAL
The ruid or euid is out of range.
EPERM
The calling process doesn't have the PROCMGR_AID_SETUID ability enabled, and you tried to change the effective user ID to a value other than the real or saved set-user ID.

Or:

The calling process doesn't have the PROCMGR_AID_SETUID ability enabled, and you tried to change the real user ID to a value other than the effective user ID.

Classification:

POSIX 1003.1 XSI

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

Last modified: 2013-12-23

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