1/*
2 * Copyright (c) 1984 through 2008, William LeFebvre
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 *     * Redistributions in binary form must reproduce the above
12 * copyright notice, this list of conditions and the following disclaimer
13 * in the documentation and/or other materials provided with the
14 * distribution.
15 *
16 *     * Neither the name of William LeFebvre nor the names of other
17 * contributors may be used to endorse or promote products derived from
18 * this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33/*
34 *  Top users/processes display for Unix
35 *  Version 3
36 */
37
38/*
39 *  Username translation code for top.
40 *
41 *  These routines handle uid to username mapping.  They use a hash table to
42 *  reduce reading overhead.  Entries are refreshed every EXPIRETIME seconds.
43 *
44 *  The old ad-hoc hash functions have been replaced with something a little
45 *  more formal and (hopefully) more robust (found in hash.c)
46 */
47
48#include "os.h"
49
50#include <pwd.h>
51
52#include "top.h"
53#include "utils.h"
54#include "hash.h"
55#include "username.h"
56
57#define EXPIRETIME (60 * 5)
58
59/* we need some sort of idea how long usernames can be */
60#ifndef MAXLOGNAME
61#ifdef _POSIX_LOGIN_NAME_MAX
62#define MAXLOGNAME _POSIX_LOGIN_NAME_MAX
63#else
64#define MAXLOGNAME 9
65#endif
66#endif
67
68struct hash_data {
69    int    uid;
70    char   name[MAXLOGNAME];  /* big enough? */
71    time_t expire;
72};
73
74hash_table *userhash;
75
76
77void
78init_username(void)
79
80{
81    userhash = hash_create(211);
82}
83
84char *
85username(int xuid)
86
87{
88    struct hash_data *data;
89    struct passwd *pw;
90    time_t now;
91
92    /* what time is it? */
93    now = time(NULL);
94
95    /* get whatever is in the cache */
96    data = hash_lookup_uint(userhash, (unsigned int)xuid);
97
98    /* if we had a cache miss, then create space for a new entry */
99    if (data == NULL)
100    {
101	/* make space */
102	data = emalloc(sizeof(struct hash_data));
103
104	/* fill in some data, including an already expired time */
105	data->uid = xuid;
106	data->expire = (time_t)0;
107
108	/* add it to the hash: the rest gets filled in later */
109	hash_add_uint(userhash, xuid, data);
110    }
111
112    /* Now data points to the correct hash entry for "xuid".  If this is
113       a new entry, then expire is 0 and the next test will be true. */
114    if (data->expire <= now)
115    {
116	if ((pw = getpwuid(xuid)) != NULL)
117	{
118	    strncpy(data->name, pw->pw_name, MAXLOGNAME-1);
119	    data->expire = now + EXPIRETIME;
120	    dprintf("username: updating %d with %s, expires %d\n",
121		    data->uid, data->name, data->expire);
122	}
123	else
124	{
125	    /* username doesnt exist ... so invent one */
126	    snprintf(data->name, sizeof(data->name), "%d", xuid);
127	    data->expire = now + EXPIRETIME;
128	    dprintf("username: updating %d with %s, expires %d\n",
129		    data->uid, data->name, data->expire);
130	}
131    }
132
133    /* return what we have */
134    return data->name;
135}
136
137int
138userid(char *xusername)
139
140{
141    struct passwd *pwd;
142
143    if ((pwd = getpwnam(xusername)) == NULL)
144    {
145	return(-1);
146    }
147
148    /* return our result */
149    return(pwd->pw_uid);
150}
151
152