getresuid, getresgid - get real, effective and saved user/group IDs
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <unistd.h>
int getresuid(uid_t *ruid, uid_t *euid, uid_t
*suid);
int getresgid(gid_t *rgid, gid_t *egid, gid_t
*sgid);
getresuid() returns the real UID, the effective UID, and the saved
set-user-ID of the calling process, in the arguments
ruid,
euid,
and
suid, respectively.
getresgid() performs the analogous task
for the process's group IDs.
On success, zero is returned. On error, -1 is returned, and
errno is set
appropriately.
- EFAULT
- One of the arguments specified an address outside the calling program's
address space.
These system calls appeared on Linux starting with kernel 2.1.44.
The prototypes are given by glibc since version 2.3.2, provided
_GNU_SOURCE is defined.
These calls are nonstandard; they also appear on HP-UX and some of the BSDs.
The original Linux
getresuid() and
getresgid() system calls
supported only 16-bit user and group IDs. Subsequently, Linux 2.4 added
getresuid32() and
getresgid32(), supporting 32-bit IDs. The
glibc
getresuid() and
getresgid() wrapper functions
transparently deal with the variations across kernel versions.
getuid(2),
setresuid(2),
setreuid(2),
setuid(2),
credentials(7)