1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
/* $OpenBSD: username.c,v 1.11 2003/06/15 16:24:44 millert 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 "utils.h"
struct hash_el {
uid_t uid;
char name[9];
};
static int enter_user(uid_t, char *, int);
static int get_user(uid_t);
#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_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, 1);
/* return our result */
return (pwd->pw_uid);
}
/*
* wecare: 1 = enter it always, 0 = nice to have
*/
static int
enter_user(uid_t uid, char *name, int wecare)
{
int hashindex;
#ifdef DEBUG
fprintf(stderr, "enter_hash(%u, %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) strlcpy(hash_table[hashindex].name, name,
sizeof(hash_table[hashindex].name));
return (hashindex);
}
/*
* Get a userid->name mapping from the system.
* If the passwd database is hashed (#define RANDOM_PW), we
* just handle this uid. Otherwise we scan the passwd file
* and cache any entries we pass over while looking.
*/
static int
get_user(uid_t uid)
{
struct passwd *pwd;
#ifdef RANDOM_PW
/* no performance penalty for using getpwuid makes it easy */
if ((pwd = getpwuid(uid)) != NULL)
return (enter_user(pwd->pw_uid, pwd->pw_name, 1));
#else
int from_start = 0;
/*
* If we just called getpwuid each time, things would be very slow
* since that just iterates through the passwd file each time. So,
* we walk through the file instead (using getpwent) and cache each
* entry as we go. Once the right record is found, we cache it and
* return immediately. The next time we come in, getpwent will get
* the next record. In theory, we never have to read the passwd file
* a second time (because we cache everything we read). But in
* practice, the cache may not be large enough, so if we don't find
* it the first time we have to scan the file a second time. This
* is not very efficient, but it will do for now.
*/
while (from_start++ < 2) {
while ((pwd = getpwent()) != NULL) {
if (pwd->pw_uid == uid)
return (enter_user(pwd->pw_uid, pwd->pw_name, 1));
(void) enter_user(pwd->pw_uid, pwd->pw_name, 0);
}
/* try again */
setpwent();
}
#endif
/* if we can't find the name at all, then use the uid as the name */
return (enter_user(uid, itoa7(uid), 1));
}
|
