procps/proc/pwcache.c
2015-06-26 22:37:53 +10:00

94 lines
2.5 KiB
C

/*
* pwcache.c - memory cache passwd file handling
*
* Copyright (C) 1992-1998 by Michael K. Johnson, johnsonm@redhat.com
* Note: most likely none of his code remains
*
* Copyright 2002, Albert Cahalan
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <stdlib.h>
#include <pwd.h>
#include <grp.h>
#include "alloc.h"
#include "pwcache.h"
#include "procps-private.h"
// might as well fill cache lines... else we waste memory anyway
#define HASHSIZE 64 /* power of 2 */
#define HASH(x) ((x) & (HASHSIZE - 1))
static struct pwbuf {
struct pwbuf *next;
uid_t uid;
char name[P_G_SZ];
} *pwhash[HASHSIZE];
PROCPS_EXPORT char *user_from_uid(uid_t uid) {
struct pwbuf **p;
struct passwd *pw;
p = &pwhash[HASH(uid)];
while (*p) {
if ((*p)->uid == uid)
return((*p)->name);
p = &(*p)->next;
}
*p = (struct pwbuf *) xmalloc(sizeof(struct pwbuf));
(*p)->uid = uid;
pw = getpwuid(uid);
if(!pw || strlen(pw->pw_name) >= P_G_SZ)
sprintf((*p)->name, "%u", uid);
else
strcpy((*p)->name, pw->pw_name);
(*p)->next = NULL;
return((*p)->name);
}
static struct grpbuf {
struct grpbuf *next;
gid_t gid;
char name[P_G_SZ];
} *grphash[HASHSIZE];
PROCPS_EXPORT char *group_from_gid(gid_t gid) {
struct grpbuf **g;
struct group *gr;
g = &grphash[HASH(gid)];
while (*g) {
if ((*g)->gid == gid)
return((*g)->name);
g = &(*g)->next;
}
*g = (struct grpbuf *) xmalloc(sizeof(struct grpbuf));
(*g)->gid = gid;
gr = getgrgid(gid);
if (!gr || strlen(gr->gr_name) >= P_G_SZ)
sprintf((*g)->name, "%u", gid);
else
strcpy((*g)->name, gr->gr_name);
(*g)->next = NULL;
return((*g)->name);
}