mc/vfs/names.c
2002-11-15 06:19:34 +00:00

90 lines
2.1 KiB
C

/* Look up user and/or group names.
Copyright (C) 1988, 1992 Free Software Foundation
From GNU Tar.
GNU Tar is free software; you can redistribute it and/or modify it
under the terms of the GNU Library 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 Library General Public License for more details.
* Namespace: finduname, finduid, findgname, findgid.
*/
/*
* 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 file should be modified for non-unix systems to do something
* reasonable.
*/
#include <config.h>
#include <sys/types.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <pwd.h>
#include <grp.h>
#include "names.h"
#ifndef TUNMLEN
#define TUNMLEN 256
#endif
#ifndef TGNMLEN
#define TGNMLEN 256
#endif
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 )
int
finduid (char *uname)
{
struct passwd *pw;
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;
}
int
findgid (char *gname)
{
struct group *gr;
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;
}