seteuid()
QNX SDP8.0C Library ReferenceAPIDeveloper
Set the effective user ID
Synopsis:
#include <unistd.h>
int seteuid( uid_t uid );
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 its effective user ID to its real or effective user ID, its saved set-user ID, or to any of the user IDs identified by the PROCMGR_AID_SETUID ability (see procmgr_ability()).
The real and saved user IDs aren't changed.
Note:
QNX recommends that you do not use a negative
value for a 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.
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:
Safety: | |
---|---|
Cancellation point | No |
Signal handler | Yes |
Thread | Yes |
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