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setresuid(2) [redhat man page]

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

NAME
setresuid, setresgid - set real, effective and saved user or group ID SYNOPSIS
#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 current process. Unprivileged user processes (i.e., processes with each of real, effective and saved user ID nonzero) may change the real, effective and saved user ID, each to one of: the current uid, the current effective uid or the current saved uid. The super-user may set real, effective and saved user ID to arbitrary values. If one of the parameters equals -1, the corresponding value is not changed. Completely analogously, setresgid sets the real, effective and saved group ID's of the current process, with the same restrictions for pro- cesses with each of real, effective and saved user ID nonzero. RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is set appropriately. ERRORS
EPERM The current process was not privileged and tried to change the IDs is a not allowed way. CONFORMING TO
This call is nonstandard. HISTORY
This system call was first introduced in HP-UX. It is available under Linux since Linux 2.1.44. These days it is also found in FreeBSD (for emulation of Linux binaries). NOTES
Under HP-UX and FreeBSD the prototype is found in <unistd.h>. Under Linux there is so far no include file giving the prototype - this is a glibc bug. Programs using this system call must add the prototype themselves. SEE ALSO
getuid(2), setuid(2), setreuid(2), getresuid(2) Linux 2.1.44 2001-11-15 SETRESUID(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 #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. SEE ALSO
getresuid(2), getuid(2), setfsgid(2), setfsuid(2), setreuid(2), setuid(2), capabilities(7), credentials(7), feature_test_macros(7) COLOPHON
This page is part of release 3.27 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 2007-07-26 SETRESUID(2)

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