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
68 struct hash_data {
69 int uid;
70 char name[MAXLOGNAME]; /* big enough? */
71 time_t expire;
72 };
73
74 hash_table *userhash;
75
76
77 void
init_username(void)78 init_username(void)
79
80 {
81 userhash = hash_create(211);
82 }
83
84 char *
username(int xuid)85 username(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
137 int
userid(char * xusername)138 userid(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