/usr.bin/top/username.c
C | 144 lines | 60 code | 22 blank | 62 comment | 11 complexity | ac9dc14fbdb30b794c6bae6c2a6a47b7 MD5 | raw file
Possible License(s): LGPL-2.0, MPL-2.0-no-copyleft-exception, GPL-3.0, AGPL-1.0, MIT, ISC, LGPL-2.1, GPL-2.0, BSD-3-Clause, 0BSD
- /* $OpenBSD: username.c,v 1.16 2009/07/22 15:27:52 deraadt Exp $ */
- /*
- * Top users/processes display for Unix
- * Version 3
- *
- * Copyright (c) 1984, 1989, William LeFebvre, Rice University
- * Copyright (c) 1989, 1990, 1992, William LeFebvre, Northwestern University
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
- * IN NO EVENT SHALL THE AUTHOR OR HIS EMPLOYER BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
- /*
- * Username translation code for top.
- *
- * These routines handle uid to username mapping.
- * They use a hashing table scheme to reduce reading overhead.
- * For the time being, these are very straightforward hashing routines.
- * Maybe someday I'll put in something better. But with the advent of
- * "random access" password files, it might not be worth the effort.
- *
- * Changes to these have been provided by John Gilmore (gnu@toad.com).
- *
- * The hash has been simplified in this release, to avoid the
- * table overflow problems of previous releases. If the value
- * at the initial hash location is not right, it is replaced
- * by the right value. Collisions will cause us to call getpw*
- * but hey, this is a cache, not the Library of Congress.
- * This makes the table size independent of the passwd file size.
- */
- #include <sys/types.h>
- #include <stdio.h>
- #include <string.h>
- #include <pwd.h>
- #include "top.local.h"
- #include "top.h"
- #include "utils.h"
- struct hash_el {
- uid_t uid;
- char name[_PW_NAME_LEN + 1];
- };
- static int enter_user(uid_t, char *);
- static int get_user(uid_t);
- #define is_empty_hash(x) (hash_table[x].name[0] == 0)
- /*
- * Simple minded hashing function, assumes i is unsigned.
- */
- #define hashit(i) (i % Table_size)
- struct hash_el hash_table[Table_size];
- char *
- username(uid_t uid)
- {
- int hashindex;
- hashindex = hashit(uid);
- if (is_empty_hash(hashindex) || (hash_table[hashindex].uid != uid)) {
- /* not here or not right -- get it out of passwd */
- hashindex = get_user(uid);
- }
- return (hash_table[hashindex].name);
- }
- uid_t
- userid(char *username)
- {
- struct passwd *pwd;
- /*
- * Eventually we want this to enter everything in the hash table, but
- * for now we just do it simply and remember just the result.
- */
- if ((pwd = getpwnam(username)) == NULL)
- return ((uid_t)-1);
- /* enter the result in the hash table */
- enter_user(pwd->pw_uid, username);
- /* return our result */
- return (pwd->pw_uid);
- }
- static int
- enter_user(uid_t uid, char *name)
- {
- int hashindex;
- #ifdef DEBUG
- fprintf(stderr, "enter_hash(%u, %s)\n", uid, name);
- #endif
- hashindex = hashit(uid);
- if (!is_empty_hash(hashindex)) {
- if (hash_table[hashindex].uid == uid)
- return (hashindex); /* Fortuitous find */
- }
- /* empty or wrong slot -- fill it with new value */
- hash_table[hashindex].uid = uid;
- (void) strlcpy(hash_table[hashindex].name, name,
- sizeof(hash_table[hashindex].name));
- return (hashindex);
- }
- /*
- * Get a userid->name mapping from the system.
- */
- static int
- get_user(uid_t uid)
- {
- struct passwd *pwd;
- /* no performance penalty for using getpwuid makes it easy */
- if ((pwd = getpwuid(uid)) != NULL)
- return (enter_user(pwd->pw_uid, pwd->pw_name));
- /* if we can't find the name at all, then use the uid as the name */
- return (enter_user(uid, format_uid(uid)));
- }