LOGIN_CAP(3) BSD Programmer's Manual LOGIN_CAP(3)NAME
login_getclass, login_getstyle, login_getcapbool, login_getcapnum,
login_getcapsize, login_getcapstr, login_getcaptime, login_close,
secure_path, setclasscontext, setusercontext - query login.conf database
about a user class
SYNOPSIS
#include <login_cap.h>
login_cap_t *
login_getclass(char *class);
char *
login_getstyle(login_cap_t *lc, char *style, char *type);
int
login_getcapbool(login_cap_t *lc, char *cap, u_int def);
quad_t
login_getcapnum(login_cap_t *lc, char *cap, quad_t def, quad_t err);
quad_t
login_getcapsize(login_cap_t *lc, char *cap, quad_t def, quad_t err);
char *
login_getcapstr(login_cap_t *lc, char *cap, char *def, char *err);
quad_t
login_getcaptime(login_cap_t *lc, char *cap, quad_t def, quad_t err);
void
login_close(login_cap_t *lc);
int
secure_path(char *path);
int
setclasscontext(char *class, u_int flags);
int
setusercontext(login_cap_t *lc, struct passwd *pwd, uid_t uid,
u_int flags);
DESCRIPTION
The login_getclass() function extracts the entry specified by class (or
default if class is NULL or the empty string) from /etc/login.conf (see
login.conf(5)). If the entry is found, a login_cap_t pointer is re-
turned. NULL is returned if the user class is not found. When the
login_cap_t structure is no longer needed, is should be freed by the
login_close() function.
Once lc has been returned by login_getclass(), any of the other login_*()
functions may be called. The login_getstyle() function is used to obtain
the style of authentication that should be used for this user class. The
style argument may either be NULL or the desired style of authentication.
If NULL, the first available authentication style will be used. The type
argument refers to the type of authentication being performed. This is
used to override the standard auth entry in the database. By convention
this should be of the form "auth-type". Future releases may remove the
requirement for the "auth-" prefix and add it if it is missing. If type
is NULL then only "auth" will be looked at. (See login.conf(5)). The
login_getstyle() function will return NULL if the desired style of au-
thentication is not available, or if no style is available.
The login_getcapnum(), login_getcapsize(), login_getcapstr(), and
login_getcaptime() functions all query the database entry for a field
named cap. If the field is found, its value is returned. If the field is
not found, the value specified by def is returned. If an error is en-
countered while trying to find the field, err is returned. See lo-
gin.conf(5) for a discussion of the various textual forms the value may
take. The login_getcapbool() function is slightly different. It returns
def if no capabilities were found for this class (typically meaning that
the default class was used and the /etc/login.conf file is missing). It
returns a non-zero value if cap, with no value, was found, zero other-
wise.
The secure_path() function takes a path name and returns 0 if the path
name is secure, -1 if not. To be secure a path must exist, be a regular
file (and not a directory), owned by root, and only writable by the owner
(root).
The setclasscontext() function takes class, the name of a user class, and
sets the resources defined by that class according to flags. Only the
LOGIN_SETPATH, LOGIN_SETPRIORITY, LOGIN_SETRESOURCES, and LOGIN_SETUMASK
bits are used. (See setusercontext() below). It returns 0 on success
and -1 on failure.
The setusercontext() function sets the resources according to flags. The
lc argument, if not NULL, contains the class information that should be
used. The pwd argument, if not NULL, provides information about the us-
er. Both lc and pwd cannot be NULL. The uid argument is used in place
of the user id contained in the pwd structure when calling setuid(2).
The various bits available to be or-ed together to make up flags are:
LOGIN_SETGROUP Set the group id and call initgroups(3). Requires
the pwd field be specified.
LOGIN_SETLOGIN Sets the login name by setlogin(2). Requires the
pwd field be specified.
LOGIN_SETPATH Sets the PATH environment variable.
LOGIN_SETPRIORITY Sets the priority by setpriority(2).
LOGIN_SETRESOURCES Sets the various system resources by setrlimit(2).
LOGIN_SETUMASK Sets the umask by umask(2).
LOGIN_SETUSER Sets the user id to uid by setuid(2).
LOGIN_SETALL Sets all of the above.
SEE ALSOsetlogin(2), setpriority(2), setrlimit(2), setuid(2), umask(2),
initgroups(3), login.conf(5)BSDI BSD/OS July 16, 1996 2
