124139Sjoerg/* 224139Sjoerg * Top users/processes display for Unix 324139Sjoerg * Version 3 424139Sjoerg * 524139Sjoerg * This program may be freely redistributed, 624139Sjoerg * but this entire comment MUST remain intact. 724139Sjoerg * 824139Sjoerg * Copyright (c) 1984, 1989, William LeFebvre, Rice University 924139Sjoerg * Copyright (c) 1989, 1990, 1992, William LeFebvre, Northwestern University 1098069Smike * 1198069Smike * $FreeBSD$ 1224139Sjoerg */ 1324139Sjoerg 1424139Sjoerg/* 1524139Sjoerg * Username translation code for top. 1624139Sjoerg * 1724139Sjoerg * These routines handle uid to username mapping. 1824139Sjoerg * They use a hashing table scheme to reduce reading overhead. 1924139Sjoerg * For the time being, these are very straightforward hashing routines. 2024139Sjoerg * Maybe someday I'll put in something better. But with the advent of 2124139Sjoerg * "random access" password files, it might not be worth the effort. 2224139Sjoerg * 2324139Sjoerg * Changes to these have been provided by John Gilmore (gnu@toad.com). 2424139Sjoerg * 2524139Sjoerg * The hash has been simplified in this release, to avoid the 2624139Sjoerg * table overflow problems of previous releases. If the value 2724139Sjoerg * at the initial hash location is not right, it is replaced 2824139Sjoerg * by the right value. Collisions will cause us to call getpw* 2924139Sjoerg * but hey, this is a cache, not the Library of Congress. 3024139Sjoerg * This makes the table size independent of the passwd file size. 3124139Sjoerg */ 3224139Sjoerg 33200979Sed#include <sys/param.h> 3498069Smike#include <sys/types.h> 3524139Sjoerg#include <stdio.h> 3624139Sjoerg#include <pwd.h> 3724139Sjoerg 3824139Sjoerg#include "top.local.h" 3924139Sjoerg#include "utils.h" 4024139Sjoerg 4124139Sjoergstruct hash_el { 4224139Sjoerg int uid; 43200979Sed char name[MAXLOGNAME]; 4424139Sjoerg}; 4524139Sjoerg 4624139Sjoerg#define is_empty_hash(x) (hash_table[x].name[0] == 0) 4724139Sjoerg 4824139Sjoerg/* simple minded hashing function */ 4924139Sjoerg/* Uid "nobody" is -2 results in hashit(-2) = -2 which is out of bounds for 5024139Sjoerg the hash_table. Applied abs() function to fix. 2/16/96 tpugh 5124139Sjoerg*/ 5224139Sjoerg#define hashit(i) (abs(i) % Table_size) 5324139Sjoerg 5424139Sjoerg/* K&R requires that statically declared tables be initialized to zero. */ 5524139Sjoerg/* We depend on that for hash_table and YOUR compiler had BETTER do it! */ 5624139Sjoergstruct hash_el hash_table[Table_size]; 5724139Sjoerg 5824139Sjoerginit_hash() 5924139Sjoerg 6024139Sjoerg{ 6124139Sjoerg /* 6224139Sjoerg * There used to be some steps we had to take to initialize things. 6324139Sjoerg * We don't need to do that anymore, but we will leave this stub in 6424139Sjoerg * just in case future changes require initialization steps. 6524139Sjoerg */ 6624139Sjoerg} 6724139Sjoerg 6824139Sjoergchar *username(uid) 6924139Sjoerg 7024139Sjoergregister int uid; 7124139Sjoerg 7224139Sjoerg{ 7324139Sjoerg register int hashindex; 7424139Sjoerg 7524139Sjoerg hashindex = hashit(uid); 7624139Sjoerg if (is_empty_hash(hashindex) || (hash_table[hashindex].uid != uid)) 7724139Sjoerg { 7824139Sjoerg /* not here or not right -- get it out of passwd */ 7924139Sjoerg hashindex = get_user(uid); 8024139Sjoerg } 8124139Sjoerg return(hash_table[hashindex].name); 8224139Sjoerg} 8324139Sjoerg 8424139Sjoergint userid(username) 8524139Sjoerg 8624139Sjoergchar *username; 8724139Sjoerg 8824139Sjoerg{ 8924139Sjoerg struct passwd *pwd; 9024139Sjoerg 9124139Sjoerg /* Eventually we want this to enter everything in the hash table, 9224139Sjoerg but for now we just do it simply and remember just the result. 9324139Sjoerg */ 9424139Sjoerg 9524139Sjoerg if ((pwd = getpwnam(username)) == NULL) 9624139Sjoerg { 9724139Sjoerg return(-1); 9824139Sjoerg } 9924139Sjoerg 10024139Sjoerg /* enter the result in the hash table */ 10124139Sjoerg enter_user(pwd->pw_uid, username, 1); 10224139Sjoerg 10324139Sjoerg /* return our result */ 10424139Sjoerg return(pwd->pw_uid); 10524139Sjoerg} 10624139Sjoerg 10724139Sjoergint enter_user(uid, name, wecare) 10824139Sjoerg 10924139Sjoergregister int uid; 11024139Sjoergregister char *name; 11124139Sjoergint wecare; /* 1 = enter it always, 0 = nice to have */ 11224139Sjoerg 11324139Sjoerg{ 11424139Sjoerg register int hashindex; 11524139Sjoerg 11624139Sjoerg#ifdef DEBUG 11724139Sjoerg fprintf(stderr, "enter_hash(%d, %s, %d)\n", uid, name, wecare); 11824139Sjoerg#endif 11924139Sjoerg 12024139Sjoerg hashindex = hashit(uid); 12124139Sjoerg 12224139Sjoerg if (!is_empty_hash(hashindex)) 12324139Sjoerg { 12424139Sjoerg if (!wecare) 12524139Sjoerg return 0; /* Don't clobber a slot for trash */ 12624139Sjoerg if (hash_table[hashindex].uid == uid) 12724139Sjoerg return(hashindex); /* Fortuitous find */ 12824139Sjoerg } 12924139Sjoerg 13024139Sjoerg /* empty or wrong slot -- fill it with new value */ 13124139Sjoerg hash_table[hashindex].uid = uid; 132200979Sed (void) strncpy(hash_table[hashindex].name, name, MAXLOGNAME - 1); 13324139Sjoerg return(hashindex); 13424139Sjoerg} 13524139Sjoerg 13624139Sjoerg/* 13724139Sjoerg * Get a userid->name mapping from the system. 13824139Sjoerg * If the passwd database is hashed (#define RANDOM_PW), we 13924139Sjoerg * just handle this uid. Otherwise we scan the passwd file 14024139Sjoerg * and cache any entries we pass over while looking. 14124139Sjoerg */ 14224139Sjoerg 14324139Sjoergint get_user(uid) 14424139Sjoerg 14524139Sjoergregister int uid; 14624139Sjoerg 14724139Sjoerg{ 14824139Sjoerg struct passwd *pwd; 14924139Sjoerg 15024139Sjoerg#ifdef RANDOM_PW 15124139Sjoerg /* no performance penalty for using getpwuid makes it easy */ 15224139Sjoerg if ((pwd = getpwuid(uid)) != NULL) 15324139Sjoerg { 15424139Sjoerg return(enter_user(pwd->pw_uid, pwd->pw_name, 1)); 15524139Sjoerg } 15624139Sjoerg#else 15724139Sjoerg 15824139Sjoerg int from_start = 0; 15924139Sjoerg 16024139Sjoerg /* 16124139Sjoerg * If we just called getpwuid each time, things would be very slow 16224139Sjoerg * since that just iterates through the passwd file each time. So, 16324139Sjoerg * we walk through the file instead (using getpwent) and cache each 16424139Sjoerg * entry as we go. Once the right record is found, we cache it and 16524139Sjoerg * return immediately. The next time we come in, getpwent will get 16624139Sjoerg * the next record. In theory, we never have to read the passwd file 16724139Sjoerg * a second time (because we cache everything we read). But in 16824139Sjoerg * practice, the cache may not be large enough, so if we don't find 16924139Sjoerg * it the first time we have to scan the file a second time. This 17024139Sjoerg * is not very efficient, but it will do for now. 17124139Sjoerg */ 17224139Sjoerg 17324139Sjoerg while (from_start++ < 2) 17424139Sjoerg { 17524139Sjoerg while ((pwd = getpwent()) != NULL) 17624139Sjoerg { 17724139Sjoerg if (pwd->pw_uid == uid) 17824139Sjoerg { 17924139Sjoerg return(enter_user(pwd->pw_uid, pwd->pw_name, 1)); 18024139Sjoerg } 18124139Sjoerg (void) enter_user(pwd->pw_uid, pwd->pw_name, 0); 18224139Sjoerg } 18324139Sjoerg /* try again */ 18424139Sjoerg setpwent(); 18524139Sjoerg } 18624139Sjoerg#endif 18724139Sjoerg /* if we can't find the name at all, then use the uid as the name */ 18824139Sjoerg return(enter_user(uid, itoa7(uid), 1)); 18924139Sjoerg} 190