Annotation of src/usr.bin/top/username.c, Revision 1.11
1.11 ! millert 1: /* $OpenBSD: username.c,v 1.10 2003/06/13 21:52:25 deraadt Exp $ */
1.1 downsj 2:
3: /*
4: * Top users/processes display for Unix
5: * Version 3
6: *
1.7 deraadt 7: * Copyright (c) 1984, 1989, William LeFebvre, Rice University
8: * Copyright (c) 1989, 1990, 1992, William LeFebvre, Northwestern University
1.1 downsj 9: *
1.7 deraadt 10: * Redistribution and use in source and binary forms, with or without
11: * modification, are permitted provided that the following conditions
12: * are met:
13: * 1. Redistributions of source code must retain the above copyright
14: * notice, this list of conditions and the following disclaimer.
15: * 2. Redistributions in binary form must reproduce the above copyright
16: * notice, this list of conditions and the following disclaimer in the
17: * documentation and/or other materials provided with the distribution.
18: *
19: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22: * IN NO EVENT SHALL THE AUTHOR OR HIS EMPLOYER BE LIABLE FOR ANY DIRECT, INDIRECT,
23: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.1 downsj 29: */
30:
31: /*
32: * Username translation code for top.
33: *
34: * These routines handle uid to username mapping.
35: * They use a hashing table scheme to reduce reading overhead.
36: * For the time being, these are very straightforward hashing routines.
37: * Maybe someday I'll put in something better. But with the advent of
38: * "random access" password files, it might not be worth the effort.
39: *
40: * Changes to these have been provided by John Gilmore (gnu@toad.com).
41: *
42: * The hash has been simplified in this release, to avoid the
43: * table overflow problems of previous releases. If the value
44: * at the initial hash location is not right, it is replaced
45: * by the right value. Collisions will cause us to call getpw*
46: * but hey, this is a cache, not the Library of Congress.
47: * This makes the table size independent of the passwd file size.
48: */
49:
1.2 downsj 50: #include <sys/types.h>
1.1 downsj 51: #include <stdio.h>
1.2 downsj 52: #include <string.h>
1.1 downsj 53: #include <pwd.h>
54:
55: #include "top.local.h"
56: #include "utils.h"
57:
58: struct hash_el {
1.11 ! millert 59: uid_t uid;
! 60: char name[9];
1.1 downsj 61: };
62:
1.9 deraadt 63: static int enter_user(uid_t, char *, int);
64: static int get_user(uid_t);
1.2 downsj 65:
1.11 ! millert 66: #define is_empty_hash(x) (hash_table[x].name[0] == 0)
1.1 downsj 67:
68: /* simple minded hashing function */
1.9 deraadt 69: /*
70: * Uid "nobody" is -2 results in hashit(-2) = -2 which is out of bounds for
71: * the hash_table. Applied abs() function to fix. 2/16/96 tpugh
72: */
1.11 ! millert 73: #define hashit(i) (abs(i) % Table_size)
1.1 downsj 74:
75: /* K&R requires that statically declared tables be initialized to zero. */
76: /* We depend on that for hash_table and YOUR compiler had BETTER do it! */
1.9 deraadt 77: struct hash_el hash_table[Table_size];
1.1 downsj 78:
1.8 pvalchev 79: char *
80: username(uid_t uid)
1.1 downsj 81: {
1.9 deraadt 82: int hashindex;
1.1 downsj 83:
1.9 deraadt 84: hashindex = hashit(uid);
85: if (is_empty_hash(hashindex) || (hash_table[hashindex].uid != uid)) {
86: /* not here or not right -- get it out of passwd */
87: hashindex = get_user(uid);
88: }
89: return (hash_table[hashindex].name);
1.1 downsj 90: }
91:
1.8 pvalchev 92: uid_t
93: userid(char *username)
1.1 downsj 94: {
1.9 deraadt 95: struct passwd *pwd;
96:
97: /*
98: * Eventually we want this to enter everything in the hash table, but
99: * for now we just do it simply and remember just the result.
100: */
101: if ((pwd = getpwnam(username)) == NULL)
1.11 ! millert 102: return ((uid_t)-1);
1.1 downsj 103:
1.9 deraadt 104: /* enter the result in the hash table */
105: enter_user(pwd->pw_uid, username, 1);
1.1 downsj 106:
1.9 deraadt 107: /* return our result */
108: return (pwd->pw_uid);
1.1 downsj 109: }
110:
1.9 deraadt 111: /*
112: * wecare: 1 = enter it always, 0 = nice to have
113: */
1.8 pvalchev 114: static int
115: enter_user(uid_t uid, char *name, int wecare)
1.1 downsj 116: {
1.9 deraadt 117: int hashindex;
1.1 downsj 118:
119: #ifdef DEBUG
1.9 deraadt 120: fprintf(stderr, "enter_hash(%u, %s, %d)\n", uid, name, wecare);
1.1 downsj 121: #endif
122:
1.9 deraadt 123: hashindex = hashit(uid);
1.1 downsj 124:
1.9 deraadt 125: if (!is_empty_hash(hashindex)) {
126: if (!wecare)
127: return 0; /* Don't clobber a slot for trash */
128: if (hash_table[hashindex].uid == uid)
129: return (hashindex); /* Fortuitous find */
130: }
131: /* empty or wrong slot -- fill it with new value */
132: hash_table[hashindex].uid = uid;
133: (void) strlcpy(hash_table[hashindex].name, name,
134: sizeof(hash_table[hashindex].name));
135: return (hashindex);
1.1 downsj 136: }
137:
138: /*
139: * Get a userid->name mapping from the system.
140: * If the passwd database is hashed (#define RANDOM_PW), we
141: * just handle this uid. Otherwise we scan the passwd file
142: * and cache any entries we pass over while looking.
143: */
1.8 pvalchev 144: static int
145: get_user(uid_t uid)
1.1 downsj 146: {
1.9 deraadt 147: struct passwd *pwd;
1.1 downsj 148:
149: #ifdef RANDOM_PW
1.9 deraadt 150: /* no performance penalty for using getpwuid makes it easy */
151: if ((pwd = getpwuid(uid)) != NULL)
152: return (enter_user(pwd->pw_uid, pwd->pw_name, 1));
1.1 downsj 153: #else
154:
1.9 deraadt 155: int from_start = 0;
1.1 downsj 156:
1.9 deraadt 157: /*
158: * If we just called getpwuid each time, things would be very slow
159: * since that just iterates through the passwd file each time. So,
160: * we walk through the file instead (using getpwent) and cache each
161: * entry as we go. Once the right record is found, we cache it and
162: * return immediately. The next time we come in, getpwent will get
163: * the next record. In theory, we never have to read the passwd file
164: * a second time (because we cache everything we read). But in
165: * practice, the cache may not be large enough, so if we don't find
166: * it the first time we have to scan the file a second time. This
167: * is not very efficient, but it will do for now.
168: */
169: while (from_start++ < 2) {
170: while ((pwd = getpwent()) != NULL) {
171: if (pwd->pw_uid == uid)
172: return (enter_user(pwd->pw_uid, pwd->pw_name, 1));
173: (void) enter_user(pwd->pw_uid, pwd->pw_name, 0);
174: }
175: /* try again */
176: setpwent();
1.1 downsj 177: }
178: #endif
1.9 deraadt 179: /* if we can't find the name at all, then use the uid as the name */
180: return (enter_user(uid, itoa7(uid), 1));
1.1 downsj 181: }
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