external/bsd/top/dist/username.c

   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
  78 init_username(void)
  79
  80 {
  81     userhash = hash_create(211);
  82 }
  83
  84 char *
  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
 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