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getresuid(2) [centos man page]

GETRESUID(2)						     Linux Programmer's Manual						      GETRESUID(2)

NAME
getresuid, getresgid - get real, effective and saved user/group IDs SYNOPSIS
#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); DESCRIPTION
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. RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is set appropriately. ERRORS
EFAULT One of the arguments specified an address outside the calling program's address space. VERSIONS
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. CONFORMING TO
These calls are nonstandard; they also appear on HP-UX and some of the BSDs. NOTES
The original Linux getresuid() and getresgid() system calls supported only 16-bit user and group IDs. Subsequently, Linux 2.4 added getre- suid32() and getresgid32(), supporting 32-bit IDs. The glibc getresuid() and getresgid() wrapper functions transparently deal with the variations across kernel versions. SEE ALSO
getuid(2), setresuid(2), setreuid(2), setuid(2), credentials(7) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 2010-11-22 GETRESUID(2)

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SETRESUID(2)						     Linux Programmer's Manual						      SETRESUID(2)

NAME
setresuid, setresgid - set real, effective and saved user or group ID SYNOPSIS
#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <unistd.h> int setresuid(uid_t ruid, uid_t euid, uid_t suid); int setresgid(gid_t rgid, gid_t egid, gid_t sgid); DESCRIPTION
setresuid() sets the real user ID, the effective user ID, and the saved set-user-ID of the calling process. Unprivileged user processes may change the real UID, effective UID, and saved set-user-ID, each to one of: the current real UID, the cur- rent effective UID or the current saved set-user-ID. Privileged processes (on Linux, those having the CAP_SETUID capability) may set the real UID, effective UID, and saved set-user-ID to arbi- trary values. If one of the arguments equals -1, the corresponding value is not changed. Regardless of what changes are made to the real UID, effective UID, and saved set-user-ID, the file system UID is always set to the same value as the (possibly new) effective UID. Completely analogously, setresgid() sets the real GID, effective GID, and saved set-group-ID of the calling process (and always modifies the file system GID to be the same as the effective GID), with the same restrictions for unprivileged processes. RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is set appropriately. ERRORS
EAGAIN uid does not match the current UID and this call would bring that user ID over its RLIMIT_NPROC resource limit. EPERM The calling process is not privileged (did not have the CAP_SETUID capability) and tried to change the IDs to values that are not permitted. VERSIONS
These calls are available under Linux since Linux 2.1.44. CONFORMING TO
These calls are nonstandard; they also appear on HP-UX and some of the BSDs. NOTES
Under HP-UX and FreeBSD, the prototype is found in <unistd.h>. Under Linux the prototype is provided by glibc since version 2.3.2. The original Linux setresuid() and setresgid() system calls supported only 16-bit user and group IDs. Subsequently, Linux 2.4 added setre- suid32() and setresgid32(), supporting 32-bit IDs. The glibc setresuid() and setresgid() wrapper functions transparently deal with the variations across kernel versions. SEE ALSO
getresuid(2), getuid(2), setfsgid(2), setfsuid(2), setreuid(2), setuid(2), capabilities(7), credentials(7) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. Linux 2010-11-22 SETRESUID(2)

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