Differential D6468 Diff 16686 username.c

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username.c

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* at the initial hash location is not right, it is replaced		* at the initial hash location is not right, it is replaced
* by the right value. Collisions will cause us to call getpw*		* by the right value. Collisions will cause us to call getpw*
* but hey, this is a cache, not the Library of Congress.		* but hey, this is a cache, not the Library of Congress.
* This makes the table size independent of the passwd file size.		* This makes the table size independent of the passwd file size.
*/		*/

#include <sys/param.h>		#include <sys/param.h>
#include <sys/types.h>		#include <sys/types.h>
#include <stdio.h>
#include <pwd.h>		#include <pwd.h>
		#include <stdio.h>
		#include <stdlib.h>
		#include <string.h>

#include "top.local.h"		#include "top.local.h"
#include "utils.h"		#include "utils.h"
		#include "username.h"

struct hash_el {		struct hash_el {
int uid;		int uid;
char name[MAXLOGNAME];		char name[MAXLOGNAME];
};		};

#define is_empty_hash(x) (hash_table[x].name[0] == 0)		#define is_empty_hash(x) (hash_table[x].name[0] == 0)

/* simple minded hashing function */		/* simple minded hashing function */
/* Uid "nobody" is -2 results in hashit(-2) = -2 which is out of bounds for		/* 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		the hash_table. Applied abs() function to fix. 2/16/96 tpugh
*/		*/
#define hashit(i) (abs(i) % Table_size)		#define hashit(i) (abs(i) % Table_size)

/* K&R requires that statically declared tables be initialized to zero. */		/* 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! */		/* We depend on that for hash_table and YOUR compiler had BETTER do it! */
struct hash_el hash_table[Table_size];		struct hash_el hash_table[Table_size];


		void
init_hash()		init_hash()

{		{
/*		/*
* There used to be some steps we had to take to initialize things.		* There used to be some steps we had to take to initialize things.
* We don't need to do that anymore, but we will leave this stub in		* We don't need to do that anymore, but we will leave this stub in
* just in case future changes require initialization steps.		* just in case future changes require initialization steps.
*/		*/
}		}

char *username(uid)		char *username(uid)

register int uid;		int uid;

{		{
register int hashindex;		register int hashindex;

hashindex = hashit(uid);		hashindex = hashit(uid);
if (is_empty_hash(hashindex) \|\| (hash_table[hashindex].uid != uid))		if (is_empty_hash(hashindex) \|\| (hash_table[hashindex].uid != uid))
{		{
/* not here or not right -- get it out of passwd */		/* not here or not right -- get it out of passwd */
Show All 22 Lines	return(-1);
enter_user(pwd->pw_uid, username, 1);		enter_user(pwd->pw_uid, username, 1);

/* return our result */		/* return our result */
return(pwd->pw_uid);		return(pwd->pw_uid);
}		}

int enter_user(uid, name, wecare)		int enter_user(uid, name, wecare)

register int uid;		int uid;
register char *name;		char *name;
int wecare; /* 1 = enter it always, 0 = nice to have */		int wecare; /* 1 = enter it always, 0 = nice to have */

{		{
register int hashindex;		register int hashindex;

#ifdef DEBUG		#ifdef DEBUG
fprintf(stderr, "enter_hash(%d, %s, %d)\n", uid, name, wecare);		fprintf(stderr, "enter_hash(%d, %s, %d)\n", uid, name, wecare);
#endif		#endif
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* Get a userid->name mapping from the system.		* Get a userid->name mapping from the system.
* If the passwd database is hashed (#define RANDOM_PW), we		* If the passwd database is hashed (#define RANDOM_PW), we
* just handle this uid. Otherwise we scan the passwd file		* just handle this uid. Otherwise we scan the passwd file
* and cache any entries we pass over while looking.		* and cache any entries we pass over while looking.
*/		*/

int get_user(uid)		int get_user(uid)

register int uid;		int uid;

{		{
struct passwd *pwd;		struct passwd *pwd;

#ifdef RANDOM_PW		#ifdef RANDOM_PW
/* no performance penalty for using getpwuid makes it easy */		/* no performance penalty for using getpwuid makes it easy */
if ((pwd = getpwuid(uid)) != NULL)		if ((pwd = getpwuid(uid)) != NULL)
{		{
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