freebsd-dev/usr.bin/top/username.c
Eitan Adler 668af25d2e top(1): pull configuration directly into header files
This sets configuration variables directly in the various header files,
avoiding the need to have special logic in our Makefile to build the
header.
2018-05-20 23:37:30 +00:00

150 lines
3.6 KiB
C

/*
* Top users/processes display for Unix
*
* This program may be freely redistributed,
* but this entire comment MUST remain intact.
*
* Copyright (c) 1984, 1989, William LeFebvre, Rice University
* Copyright (c) 1989, 1990, 1992, William LeFebvre, Northwestern University
*
* $FreeBSD$
*/
/*
* 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/param.h>
#include <sys/types.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "top.local.h"
#include "utils.h"
#include "username.h"
struct hash_el {
int uid;
char name[MAXLOGNAME];
};
#define is_empty_hash(x) (hash_table[x].name[0] == 0)
/* simple minded hashing function */
/* Uid "nobody" is -2 results in hashit(-2) = -2 which is out of bounds for
the hash_table. Applied abs() function to fix. 2/16/96 tpugh
*/
#define hashit(i) (abs(i) % Table_size)
/* K&R requires that statically declared tables be initialized to zero. */
/* We depend on that for hash_table and YOUR compiler had BETTER do it! */
struct hash_el hash_table[Table_size];
char *username(uid)
int 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);
}
int userid(username)
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(-1);
}
/* enter the result in the hash table */
enter_user(pwd->pw_uid, username, 1);
/* return our result */
return(pwd->pw_uid);
}
int enter_user(uid, name, wecare)
int uid;
char *name;
int wecare; /* 1 = enter it always, 0 = nice to have */
{
int hashindex;
#ifdef DEBUG
fprintf(stderr, "enter_hash(%d, %s, %d)\n", uid, name, wecare);
#endif
hashindex = hashit(uid);
if (!is_empty_hash(hashindex))
{
if (!wecare)
return 0; /* Don't clobber a slot for trash */
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) strncpy(hash_table[hashindex].name, name, MAXLOGNAME - 1);
return(hashindex);
}
/*
* Get a userid->name mapping from the system.
* If the passwd database is hashed (#define RANDOM_PW), we
* just handle this uid.
*/
int
get_user(int 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, 1));
}
/* if we can't find the name at all, then use the uid as the name */
return(enter_user(uid, itoa7(uid), 1));
}