NAME
ggeettllooggiinn, sseettllooggiinn - get/set login name
SYNOPSIS
##iinncclluuddee <
char * ggeettllooggiinn(void); int sseettllooggiinn(const char *name);> DESCRIPTION
The ggeettllooggiinn() routine returns the login name of the user associated withthe current session, as previously set by sseettllooggiinn(). The name is nor-
mally associated with a login shell at the time a session is created, and is inherited by all processes descended from the login shell. (This is true even if some of those processes assume another user ID, for example when su(1) is used.) SSeettllooggiinn() sets the login name of the user associated with the currentsession to name. This call is restricted to the super-user, and is nor-
mally used only when a new session is being created on behalf of the named user (for example, at login time, or when a remote shell is invoked).RETURN VALUES
If a call to ggeettllooggiinn() succeeds, it returns a pointer to a null-termi-
nated string in a static buffer. If the name has not been set, it returns NULL. If a call to sseettllooggiinn() succeeds, a value of 0 isreturned. If sseettllooggiinn() fails, a value of -1 is returned and an error
code is placed in the global location errno. EERRRROORRSS The following errors may be returned by these calls: [EFAULT] The name parameter gave an invalid address. [EINVAL] The name parameter pointed to a string that was toolong. Login names are limited to MAXLOGNAME (from
) characters, currently 12. [EPERM] The caller tried to set the login name and was not the super-user.
SEE ALSO
setsid(2)BUGS
Login names are limited in length by sseettllooggiinn(). However, lower limitsare placed on login names elsewhere in the system (UTNAMESIZE in
). In earlier versions of the system, ggeettllooggiinn() failed unless the process was associated with a login terminal. The current implementation (using sseettllooggiinn()) allows getlogin to succeed even when the process has no con-
trolling terminal. In earlier versions of the system, the value returnedby ggeettllooggiinn() could not be trusted without checking the user ID. Porta-
ble programs should probably still make this check. HISTORY The ggeettllooggiinn() function first appeared in 4.4BSD. 4.2 Berkeley Distribution June 9, 1993 4.2 Berkeley Distribution