SETRESUIDSection: Linux Programmer's Manual (2)
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NAMEsetresuid, setresgid - set real, effective and saved user or group ID
DESCRIPTIONsetresuid() sets the real user ID, the effective user ID, and the saved set-user-ID of the current 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 current 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 arbitrary values.
If one of the parameters 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 current process (and always modifies the file system GID to be the same as the effective GID), with the same restrictions for non-privileged processes.
RETURN VALUEOn success, zero is returned. On error, -1 is returned, and errno is set appropriately.
- uid does not match the current UID and this call would bring that user ID over its NPROC rlimit.
- 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.
VERSIONSThese calls are available under Linux since Linux 2.1.44.
CONFORMING TOThese calls are non-standard; they also appear on HP-UX and some of the BSDs.
NOTESUnder HP-UX and FreeBSD the prototype is found in <unistd.h>. Under Linux the prototype is given by glibc since version 2.3.2 provided _GNU_SOURCE is defined.
SEE ALSOgetresuid(2), getuid(2), setfsuid(2), setfsgid(2), setreuid(2), setuid(2), capabilities(7), feature_test_macros(7)