NetBSD/gnu/usr.bin/tar-1.11.2/names.c

150 lines
3.2 KiB
C

/* Look up user and/or group names.
Copyright (C) 1988, 1992 Free Software Foundation
This file is part of GNU Tar.
GNU Tar is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Tar is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Tar; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
/*
* Look up user and/or group names.
*
* This file should be modified for non-unix systems to do something
* reasonable.
*/
#include <sys/types.h>
#include "tar.h"
#include "port.h"
#ifndef NONAMES
/* Whole module goes away if NONAMES defined. Otherwise... */
#include <stdio.h>
#include <pwd.h>
#include <grp.h>
static int saveuid = -993;
static char saveuname[TUNMLEN];
static int my_uid = -993;
static int savegid = -993;
static char savegname[TGNMLEN];
static int my_gid = -993;
#define myuid ( my_uid < 0? (my_uid = getuid()): my_uid )
#define mygid ( my_gid < 0? (my_gid = getgid()): my_gid )
/*
* Look up a user or group name from a uid/gid, maintaining a cache.
* FIXME, for now it's a one-entry cache.
* FIXME2, the "-993" is to reduce the chance of a hit on the first lookup.
*
* This is ifdef'd because on Suns, it drags in about 38K of "yellow
* pages" code, roughly doubling the program size. Thanks guys.
*/
void
finduname (uname, uid)
char uname[TUNMLEN];
int uid;
{
struct passwd *pw;
#ifndef HAVE_GETPWUID
extern struct passwd *getpwuid ();
#endif
if (uid != saveuid)
{
saveuid = uid;
saveuname[0] = '\0';
pw = getpwuid (uid);
if (pw)
strncpy (saveuname, pw->pw_name, TUNMLEN);
}
strncpy (uname, saveuname, TUNMLEN);
}
int
finduid (uname)
char uname[TUNMLEN];
{
struct passwd *pw;
extern struct passwd *getpwnam ();
if (uname[0] != saveuname[0] /* Quick test w/o proc call */
|| 0 != strncmp (uname, saveuname, TUNMLEN))
{
strncpy (saveuname, uname, TUNMLEN);
pw = getpwnam (uname);
if (pw)
{
saveuid = pw->pw_uid;
}
else
{
saveuid = myuid;
}
}
return saveuid;
}
void
findgname (gname, gid)
char gname[TGNMLEN];
int gid;
{
struct group *gr;
#ifndef HAVE_GETGRGID
extern struct group *getgrgid ();
#endif
if (gid != savegid)
{
savegid = gid;
savegname[0] = '\0';
(void) setgrent ();
gr = getgrgid (gid);
if (gr)
strncpy (savegname, gr->gr_name, TGNMLEN);
}
(void) strncpy (gname, savegname, TGNMLEN);
}
int
findgid (gname)
char gname[TUNMLEN];
{
struct group *gr;
extern struct group *getgrnam ();
if (gname[0] != savegname[0] /* Quick test w/o proc call */
|| 0 != strncmp (gname, savegname, TUNMLEN))
{
strncpy (savegname, gname, TUNMLEN);
gr = getgrnam (gname);
if (gr)
{
savegid = gr->gr_gid;
}
else
{
savegid = mygid;
}
}
return savegid;
}
#endif