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cache.c

/*    $OpenBSD: cache.c,v 1.17 2004/03/16 03:28:34 tedu Exp $     */
/*    $NetBSD: cache.c,v 1.4 1995/03/21 09:07:10 cgd Exp $  */

/*-
 * Copyright (c) 1992 Keith Muller.
 * Copyright (c) 1992, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Keith Muller of the University of California, San Diego.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
#if 0
static const char sccsid[] = "@(#)cache.c 8.1 (Berkeley) 5/31/93";
#else
static const char rcsid[] = "$OpenBSD: cache.c,v 1.17 2004/03/16 03:28:34 tedu Exp $";
#endif
#endif /* not lint */

#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <string.h>
#include <stdio.h>
#include <pwd.h>
#include <grp.h>
#include <unistd.h>
#include <stdlib.h>
#include "pax.h"
#include "cache.h"
#include "extern.h"

/*
 * routines that control user, group, uid and gid caches (for the archive
 * member print routine).
 * IMPORTANT:
 * these routines cache BOTH hits and misses, a major performance improvement
 */

static      int pwopn = 0;          /* is password file open */
static      int gropn = 0;          /* is group file open */
static UIDC **uidtb = NULL;   /* uid to name cache */
static GIDC **gidtb = NULL;   /* gid to name cache */
static UIDC **usrtb = NULL;   /* user name to uid cache */
static GIDC **grptb = NULL;   /* group name to gid cache */

/*
 * uidtb_start
 *    creates an empty uidtb
 * Return:
 *    0 if ok, -1 otherwise
 */

int
uidtb_start(void)
{
      static int fail = 0;

      if (uidtb != NULL)
            return(0);
      if (fail)
            return(-1);
      if ((uidtb = (UIDC **)calloc(UID_SZ, sizeof(UIDC *))) == NULL) {
            ++fail;
            paxwarn(1, "Unable to allocate memory for user id cache table");
            return(-1);
      }
      return(0);
}

/*
 * gidtb_start
 *    creates an empty gidtb
 * Return:
 *    0 if ok, -1 otherwise
 */

int
gidtb_start(void)
{
      static int fail = 0;

      if (gidtb != NULL)
            return(0);
      if (fail)
            return(-1);
      if ((gidtb = (GIDC **)calloc(GID_SZ, sizeof(GIDC *))) == NULL) {
            ++fail;
            paxwarn(1, "Unable to allocate memory for group id cache table");
            return(-1);
      }
      return(0);
}

/*
 * usrtb_start
 *    creates an empty usrtb
 * Return:
 *    0 if ok, -1 otherwise
 */

int
usrtb_start(void)
{
      static int fail = 0;

      if (usrtb != NULL)
            return(0);
      if (fail)
            return(-1);
      if ((usrtb = (UIDC **)calloc(UNM_SZ, sizeof(UIDC *))) == NULL) {
            ++fail;
            paxwarn(1, "Unable to allocate memory for user name cache table");
            return(-1);
      }
      return(0);
}

/*
 * grptb_start
 *    creates an empty grptb
 * Return:
 *    0 if ok, -1 otherwise
 */

int
grptb_start(void)
{
      static int fail = 0;

      if (grptb != NULL)
            return(0);
      if (fail)
            return(-1);
      if ((grptb = (GIDC **)calloc(GNM_SZ, sizeof(GIDC *))) == NULL) {
            ++fail;
            paxwarn(1,"Unable to allocate memory for group name cache table");
            return(-1);
      }
      return(0);
}

/*
 * name_uid()
 *    caches the name (if any) for the uid. If frc set, we always return the
 *    the stored name (if valid or invalid match). We use a simple hash table.
 * Return
 *    Pointer to stored name (or a empty string)
 */

char *
name_uid(uid_t uid, int frc)
{
      struct passwd *pw;
      UIDC *ptr;

      if ((uidtb == NULL) && (uidtb_start() < 0))
            return("");

      /*
       * see if we have this uid cached
       */
      ptr = uidtb[uid % UID_SZ];
      if ((ptr != NULL) && (ptr->valid > 0) && (ptr->uid == uid)) {
            /*
             * have an entry for this uid
             */
            if (frc || (ptr->valid == VALID))
                  return(ptr->name);
            return("");
      }

      /*
       * No entry for this uid, we will add it
       */
      if (!pwopn) {
#ifdef DEBIAN
            setpwent();
#else
            setpassent(1);
#endif
            ++pwopn;
      }
      if (ptr == NULL)
            ptr = uidtb[uid % UID_SZ] = malloc(sizeof(UIDC));

      if ((pw = getpwuid(uid)) == NULL) {
            /*
             * no match for this uid in the local password file
             * a string that is the uid in numeric format
             */
            if (ptr == NULL)
                  return("");
            ptr->uid = uid;
            ptr->valid = INVALID;
            (void)snprintf(ptr->name, sizeof(ptr->name), "%lu",
                         (unsigned long)uid);
            if (frc == 0)
                  return("");
      } else {
            /*
             * there is an entry for this uid in the password file
             */
            if (ptr == NULL)
                  return(pw->pw_name);
            ptr->uid = uid;
            (void)strlcpy(ptr->name, pw->pw_name, sizeof(ptr->name));
            ptr->valid = VALID;
      }
      return(ptr->name);
}

/*
 * name_gid()
 *    caches the name (if any) for the gid. If frc set, we always return the
 *    the stored name (if valid or invalid match). We use a simple hash table.
 * Return
 *    Pointer to stored name (or a empty string)
 */

char *
name_gid(gid_t gid, int frc)
{
      struct group *gr;
      GIDC *ptr;

      if ((gidtb == NULL) && (gidtb_start() < 0))
            return("");

      /*
       * see if we have this gid cached
       */
      ptr = gidtb[gid % GID_SZ];
      if ((ptr != NULL) && (ptr->valid > 0) && (ptr->gid == gid)) {
            /*
             * have an entry for this gid
             */
            if (frc || (ptr->valid == VALID))
                  return(ptr->name);
            return("");
      }

      /*
       * No entry for this gid, we will add it
       */
      if (!gropn) {
#ifdef DEBIAN
            setgrent();
#else
            setgroupent(1);
#endif
            ++gropn;
      }
      if (ptr == NULL)
            ptr = gidtb[gid % GID_SZ] = malloc(sizeof(GIDC));

      if ((gr = getgrgid(gid)) == NULL) {
            /*
             * no match for this gid in the local group file, put in
             * a string that is the gid in numberic format
             */
            if (ptr == NULL)
                  return("");
            ptr->gid = gid;
            ptr->valid = INVALID;
            (void)snprintf(ptr->name, sizeof(ptr->name), "%lu",
                         (unsigned long)gid);
            if (frc == 0)
                  return("");
      } else {
            /*
             * there is an entry for this group in the group file
             */
            if (ptr == NULL)
                  return(gr->gr_name);
            ptr->gid = gid;
            (void)strlcpy(ptr->name, gr->gr_name, sizeof(ptr->name));
            ptr->valid = VALID;
      }
      return(ptr->name);
}

/*
 * uid_name()
 *    caches the uid for a given user name. We use a simple hash table.
 * Return
 *    the uid (if any) for a user name, or a -1 if no match can be found
 */

int
uid_name(char *name, uid_t *uid)
{
      struct passwd *pw;
      UIDC *ptr;
      int namelen;

      /*
       * return -1 for mangled names
       */
      if (((namelen = strlen(name)) == 0) || (name[0] == '\0'))
            return(-1);
      if ((usrtb == NULL) && (usrtb_start() < 0))
            return(-1);

      /*
       * look up in hash table, if found and valid return the uid,
       * if found and invalid, return a -1
       */
      ptr = usrtb[st_hash(name, namelen, UNM_SZ)];
      if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
            if (ptr->valid == INVALID)
                  return(-1);
            *uid = ptr->uid;
            return(0);
      }

      if (!pwopn) {
#ifdef DEBIAN
            setpwent();
#else
            setpassent(1);
#endif
            ++pwopn;
      }

      if (ptr == NULL)
            ptr = usrtb[st_hash(name, namelen, UNM_SZ)] =
              (UIDC *)malloc(sizeof(UIDC));

      /*
       * no match, look it up, if no match store it as an invalid entry,
       * or store the matching uid
       */
      if (ptr == NULL) {
            if ((pw = getpwnam(name)) == NULL)
                  return(-1);
            *uid = pw->pw_uid;
            return(0);
      }
      (void)strlcpy(ptr->name, name, sizeof(ptr->name));
      if ((pw = getpwnam(name)) == NULL) {
            ptr->valid = INVALID;
            return(-1);
      }
      ptr->valid = VALID;
      *uid = ptr->uid = pw->pw_uid;
      return(0);
}

/*
 * gid_name()
 *    caches the gid for a given group name. We use a simple hash table.
 * Return
 *    the gid (if any) for a group name, or a -1 if no match can be found
 */

int
gid_name(char *name, gid_t *gid)
{
      struct group *gr;
      GIDC *ptr;
      int namelen;

      /*
       * return -1 for mangled names
       */
      if (((namelen = strlen(name)) == 0) || (name[0] == '\0'))
            return(-1);
      if ((grptb == NULL) && (grptb_start() < 0))
            return(-1);

      /*
       * look up in hash table, if found and valid return the uid,
       * if found and invalid, return a -1
       */
      ptr = grptb[st_hash(name, namelen, GID_SZ)];
      if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
            if (ptr->valid == INVALID)
                  return(-1);
            *gid = ptr->gid;
            return(0);
      }

      if (!gropn) {
#ifdef DEBIAN
            setgrent();
#else
            setgroupent(1);
#endif
            ++gropn;
      }
      if (ptr == NULL)
            ptr = grptb[st_hash(name, namelen, GID_SZ)] =
              (GIDC *)malloc(sizeof(GIDC));

      /*
       * no match, look it up, if no match store it as an invalid entry,
       * or store the matching gid
       */
      if (ptr == NULL) {
            if ((gr = getgrnam(name)) == NULL)
                  return(-1);
            *gid = gr->gr_gid;
            return(0);
      }

      (void)strlcpy(ptr->name, name, sizeof(ptr->name));
      if ((gr = getgrnam(name)) == NULL) {
            ptr->valid = INVALID;
            return(-1);
      }
      ptr->valid = VALID;
      *gid = ptr->gid = gr->gr_gid;
      return(0);
}

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