FreeBSD manual
download PDF document: group_from_gid.3.pdf
PWCACHE(3) FreeBSD Library Functions Manual PWCACHE(3)
NAME
pwcache, user_from_uid, group_from_gid - cache password and group entries
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <pwd.h>
const char *
user_from_uid(uid_t uid, int nouser);
int
uid_from_user(const char *name, uid_t *uid);
int
pwcache_userdb(int (*setpassent)(int), void (*endpwent)(void),
struct passwd * (*getpwnam)(const char *),
struct passwd * (*getpwuid)(uid_t));
#include <grp.h>
const char *
group_from_gid(gid_t gid, int nogroup);
int
gid_from_group(const char *name, gid_t *gid);
int
pwcache_groupdb(int (*setgroupent)(int), void (*endgrent)(void),
struct group * (*getgrnam)(const char *),
struct group * (*getgrgid)(gid_t));
DESCRIPTION
The user_from_uid() function returns the user name associated with the
argument uid. The user name is cached so that multiple calls with the
same uid do not require additional calls to getpwuid(3). If there is no
user associated with the uid, a pointer is returned to a string
representation of the uid, unless the argument nouser is non-zero, in
which case a NULL pointer is returned.
The group_from_gid() function returns the group name associated with the
argument gid. The group name is cached so that multiple calls with the
same gid do not require additional calls to getgrgid(3). If there is no
group associated with the gid, a pointer is returned to a string
representation of the gid, unless the argument nogroup is non-zero, in
which case a NULL pointer is returned.
The uid_from_user() function returns the uid associated with the argument
name. The uid is cached so that multiple calls with the same name do not
require additional calls to getpwnam(3). If there is no uid associated
with the name, the uid_from_user() function returns -1; otherwise it
stores the uid at the location pointed to by uid and returns 0.
The gid_from_group() function returns the gid associated with the
argument name. The gid is cached so that multiple calls with the same
name do not require additional calls to getgrnam(3). If there is no gid
switching to the new routines. getpwnam and getpwuid must be provided,
and setpassent and endpwent may be NULL pointers.
The pwcache_groupdb() function changes the group database access routines
which group_from_gid() and gid_from_group() call to search for groups.
The caches are flushed and the existing endgrent() method is called
before switching to the new routines. getgrnam and getgrgid must be
provided, and setgroupent and endgrent may be NULL pointers.
ERRORS
If insufficient memory is available, user_from_uid() and group_from_gid()
may return NULL pointers. errno is set to ENOMEM.
SEE ALSO
getgrgid(3), getgrnam(3), getpwnam(3), getpwuid(3)
HISTORY
The user_from_uid() and group_from_gid() functions first appeared in
4.4BSD.
The uid_from_user() and gid_from_group() functions first appeared in
NetBSD 1.4.
The pwcache_userdb() and pwcache_groupdb() functions first appeared in
NetBSD 1.6 and FreeBSD 10.0.
FreeBSD 14.0-RELEASE-p11 May 5, 2020 FreeBSD 14.0-RELEASE-p11