freebsd-dev/usr.bin/top/username.c
Eitan Adler 1de6384221 top(1): style(9)
- split return type from function name
- Sprinkle a __pure where possible.
2018-06-13 08:52:22 +00:00

137 lines
3.4 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 <pwd.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.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 */
#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! */
static struct hash_el hash_table[Table_size];
char *
username(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(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);
}
/* wecare 1 = enter it always, 0 = nice to have */
int
enter_user(int uid, char name[], bool wecare)
{
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.
*/
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));
}