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NAMES.C
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1988-05-15
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/*
* Look up user and/or group names.
*
* This file should be modified for non-unix systems to do something
* reasonable.
*
* @(#)names.c 1.1 9/9/86 Public Domain - gnu
* MS-DOS port 2/87 by E. Roskos.
* Minix port 3/88 by E. Roskos.
*/
#include <sys/types.h>
#ifndef MSDOS
#include <pwd.h>
#include <grp.h>
#endif
#include "tar.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 )
#ifndef NONAMES
/*
* 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;
extern struct passwd *getpwuid();
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;
extern struct group *getgrgid();
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