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pwcache.c

/**   $MirOS: src/usr.sbin/makefs/nbsrc/lib/libc/gen/pwcache.c,v 1.6 2009/07/23 19:32:25 tg Exp $ */
/*    $NetBSD: pwcache.c,v 1.30 2008/04/28 20:22:59 martin Exp $  */

/*-
 * Copyright (c) 2009 Thorsten Glaser.
 * 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.
 */

/*-
 * Copyright (c) 2002 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
/*
 * XXX Undefine the renames of these functions so that we don't
 * XXX rename the versions found in the host's <pwd.h> by mistake!
 */
#undef group_from_gid
#undef user_from_uid
#endif

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)cache.c 8.1 (Berkeley) 5/31/93";
#else
__RCSID("$NetBSD: pwcache.c,v 1.30 2008/04/28 20:22:59 martin Exp $");
__IDSTRING(mbsdid, "$MirOS: src/usr.sbin/makefs/nbsrc/lib/libc/gen/pwcache.c,v 1.6 2009/07/23 19:32:25 tg Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#ifdef _LIBC
#include "namespace.h"
#endif

#include <sys/types.h>
#include <sys/param.h>

#include <assert.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#if HAVE_NBTOOL_CONFIG_H || defined(__MirBSD__) || defined(DEBIAN)
/* XXX Now, re-apply the renaming that we undid above. */
#define     group_from_gid    __nbcompat_group_from_gid
#define     user_from_uid     __nbcompat_user_from_uid
#endif

#if defined(__weak_alias) && !defined(__MirBSD__) && !defined(DEBIAN)
__weak_alias(user_from_uid,_user_from_uid)
__weak_alias(group_from_gid,_group_from_gid)
__weak_alias(pwcache_userdb,_pwcache_userdb)
__weak_alias(pwcache_groupdb,_pwcache_groupdb)
#endif

#ifdef DEBIAN
/* XXX eglibc? */
#define setgroupent     NULL
#define setpassent      NULL
#endif

#if !HAVE_PWCACHE_USERDB || HAVE_NBTOOL_CONFIG_H
#include "pwcache.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
 */

/*
 * function pointers to various name lookup routines.
 * these may be changed as necessary.
 */
static      int         (*_pwcache_setgroupent)(int)        = setgroupent;
static      void        (*_pwcache_endgrent)(void)          = endgrent;
static      struct group *    (*_pwcache_getgrnam)(const char *)  = getgrnam;
static      struct group *    (*_pwcache_getgrgid)(gid_t)         = getgrgid;
static      int         (*_pwcache_setpassent)(int)         = setpassent;
static      void        (*_pwcache_endpwent)(void)          = endpwent;
static      struct passwd *   (*_pwcache_getpwnam)(const char *)  = getpwnam;
static      struct passwd *   (*_pwcache_getpwuid)(uid_t)         = getpwuid;

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

static      int   uidtb_fail; /* uidtb_start() failed ? */
static      int   gidtb_fail; /* gidtb_start() failed ? */
static      int   usrtb_fail; /* usrtb_start() failed ? */
static      int   grptb_fail; /* grptb_start() failed ? */


static      u_int st_hash(const char *, size_t, int);
static      int   uidtb_start(void);
static      int   gidtb_start(void);
static      int   usrtb_start(void);
static      int   grptb_start(void);


static u_int
st_hash(const char *name, size_t len, int tabsz)
{
      u_int key = 0;

      _DIAGASSERT(name != NULL);

      while (len--) {
            key += *name++;
            key = (key << 8) | (key >> 24);
      }

      return (key % tabsz);
}

/*
 * uidtb_start
 *    creates an an empty uidtb
 * Return:
 *    0 if ok, -1 otherwise
 */
static int
uidtb_start(void)
{

      if (uidtb != NULL)
            return (0);
      if (uidtb_fail)
            return (-1);
      if ((uidtb = (UIDC **)calloc(UID_SZ, sizeof(UIDC *))) == NULL) {
            ++uidtb_fail;
            return (-1);
      }
      return (0);
}

/*
 * gidtb_start
 *    creates an an empty gidtb
 * Return:
 *    0 if ok, -1 otherwise
 */
static int
gidtb_start(void)
{

      if (gidtb != NULL)
            return (0);
      if (gidtb_fail)
            return (-1);
      if ((gidtb = (GIDC **)calloc(GID_SZ, sizeof(GIDC *))) == NULL) {
            ++gidtb_fail;
            return (-1);
      }
      return (0);
}

/*
 * usrtb_start
 *    creates an an empty usrtb
 * Return:
 *    0 if ok, -1 otherwise
 */
static int
usrtb_start(void)
{

      if (usrtb != NULL)
            return (0);
      if (usrtb_fail)
            return (-1);
      if ((usrtb = (UIDC **)calloc(UNM_SZ, sizeof(UIDC *))) == NULL) {
            ++usrtb_fail;
            return (-1);
      }
      return (0);
}

/*
 * grptb_start
 *    creates an an empty grptb
 * Return:
 *    0 if ok, -1 otherwise
 */
static int
grptb_start(void)
{

      if (grptb != NULL)
            return (0);
      if (grptb_fail)
            return (-1);
      if ((grptb = (GIDC **)calloc(GNM_SZ, sizeof(GIDC *))) == NULL) {
            ++grptb_fail;
            return (-1);
      }
      return (0);
}

/*
 * user_from_uid()
 *    caches the name (if any) for the uid. If noname clear, we always
 *    return the stored name (if valid or invalid match).
 *    We use a simple hash table.
 * Return
 *    Pointer to stored name (or a empty string)
 */
const char *
user_from_uid(uid_t uid, int noname)
{
      struct passwd *pw;
      UIDC *ptr, **pptr;

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

      /*
       * see if we have this uid cached
       */
      pptr = uidtb + (uid % UID_SZ);
      ptr = *pptr;

      if ((ptr != NULL) && (ptr->valid > 0) && (ptr->uid == uid)) {
            /*
             * have an entry for this uid
             */
            if (!noname || (ptr->valid == VALID))
                  return (ptr->name);
            return (NULL);
      }

      /*
       * No entry for this uid, we will add it
       */
      if (!pwopn) {
            if (_pwcache_setpassent != NULL)
                  (*_pwcache_setpassent)(1);
            ++pwopn;
      }

      if (ptr == NULL)
            *pptr = ptr = (UIDC *)malloc(sizeof(UIDC));

      if ((pw = (*_pwcache_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 (NULL);
            ptr->uid = uid;
            (void)snprintf(ptr->name, UNMLEN, "%lu", (long) uid);
            ptr->valid = INVALID;
            if (noname)
                  return (NULL);
      } 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, UNMLEN);
            ptr->valid = VALID;
      }
      return (ptr->name);
}

/*
 * group_from_gid()
 *    caches the name (if any) for the gid. If noname clear, we always
 *    return the stored name (if valid or invalid match).
 *    We use a simple hash table.
 * Return
 *    Pointer to stored name (or a empty string)
 */
const char *
group_from_gid(gid_t gid, int noname)
{
      struct group *gr;
      GIDC *ptr, **pptr;

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

      /*
       * see if we have this gid cached
       */
      pptr = gidtb + (gid % GID_SZ);
      ptr = *pptr;

      if ((ptr != NULL) && (ptr->valid > 0) && (ptr->gid == gid)) {
            /*
             * have an entry for this gid
             */
            if (!noname || (ptr->valid == VALID))
                  return (ptr->name);
            return (NULL);
      }

      /*
       * No entry for this gid, we will add it
       */
      if (!gropn) {
            if (_pwcache_setgroupent != NULL)
                  (*_pwcache_setgroupent)(1);
            ++gropn;
      }

      if (ptr == NULL)
            *pptr = ptr = (GIDC *)malloc(sizeof(GIDC));

      if ((gr = (*_pwcache_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 (NULL);
            ptr->gid = gid;
            (void)snprintf(ptr->name, GNMLEN, "%lu", (long) gid);
            ptr->valid = INVALID;
            if (noname)
                  return (NULL);
      } 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, GNMLEN);
            ptr->valid = VALID;
      }
      return (ptr->name);
}

/*
 * uid_from_user()
 *    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_from_user(const char *name, uid_t *uid)
{
      struct passwd *pw;
      UIDC *ptr, **pptr;
      size_t namelen;

      /*
       * return -1 for mangled names
       */
      if (name == NULL || ((namelen = strlen(name)) == 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
       */
      pptr = usrtb + st_hash(name, namelen, UNM_SZ);
      ptr = *pptr;

      if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
            if (ptr->valid == INVALID)
                  return (-1);
            *uid = ptr->uid;
            return (0);
      }

      if (!pwopn) {
            if (_pwcache_setpassent != NULL)
                  (*_pwcache_setpassent)(1);
            ++pwopn;
      }

      if (ptr == NULL)
            *pptr = ptr = (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 = (*_pwcache_getpwnam)(name)) == NULL)
                  return (-1);
            *uid = pw->pw_uid;
            return (0);
      }
      (void)strlcpy(ptr->name, name, UNMLEN);
      if ((pw = (*_pwcache_getpwnam)(name)) == NULL) {
            ptr->valid = INVALID;
            return (-1);
      }
      ptr->valid = VALID;
      *uid = ptr->uid = pw->pw_uid;
      return (0);
}

/*
 * gid_from_group()
 *    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_from_group(const char *name, gid_t *gid)
{
      struct group *gr;
      GIDC *ptr, **pptr;
      size_t namelen;

      /*
       * return -1 for mangled names
       */
      if (name == NULL || ((namelen = strlen(name)) == 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
       */
      pptr = grptb + st_hash(name, namelen, GID_SZ);
      ptr = *pptr;

      if ((ptr != NULL) && (ptr->valid > 0) && !strcmp(name, ptr->name)) {
            if (ptr->valid == INVALID)
                  return (-1);
            *gid = ptr->gid;
            return (0);
      }

      if (!gropn) {
            if (_pwcache_setgroupent != NULL)
                  (*_pwcache_setgroupent)(1);
            ++gropn;
      }

      if (ptr == NULL)
            *pptr = ptr = (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 = (*_pwcache_getgrnam)(name)) == NULL)
                  return (-1);
            *gid = gr->gr_gid;
            return (0);
      }

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

#define FLUSHTB(arr, len, fail)                       \
      do {                                \
            if (arr != NULL) {                  \
                  for (i = 0; i < len; i++)     \
                        if (arr[i] != NULL)     \
                              free(arr[i]);     \
                  arr = NULL;             \
            }                             \
            fail = 0;                     \
      } while (/* CONSTCOND */0);

int
pwcache_userdb(
      int         (*a_setpassent)(int),
      void        (*a_endpwent)(void),
      struct passwd *   (*a_getpwnam)(const char *),
      struct passwd *   (*a_getpwuid)(uid_t))
{
      int i;

            /* a_setpassent and a_endpwent may be NULL */
      if (a_getpwnam == NULL || a_getpwuid == NULL)
            return (-1);

      if (_pwcache_endpwent != NULL)
            (*_pwcache_endpwent)();
      FLUSHTB(uidtb, UID_SZ, uidtb_fail);
      FLUSHTB(usrtb, UNM_SZ, usrtb_fail);
      pwopn = 0;
      _pwcache_setpassent = a_setpassent;
      _pwcache_endpwent = a_endpwent;
      _pwcache_getpwnam = a_getpwnam;
      _pwcache_getpwuid = a_getpwuid;

      return (0);
}

int
pwcache_groupdb(
      int         (*a_setgroupent)(int),
      void        (*a_endgrent)(void),
      struct group *    (*a_getgrnam)(const char *),
      struct group *    (*a_getgrgid)(gid_t))
{
      int i;

            /* a_setgroupent and a_endgrent may be NULL */
      if (a_getgrnam == NULL || a_getgrgid == NULL)
            return (-1);

      if (_pwcache_endgrent != NULL)
            (*_pwcache_endgrent)();
      FLUSHTB(gidtb, GID_SZ, gidtb_fail);
      FLUSHTB(grptb, GNM_SZ, grptb_fail);
      gropn = 0;
      _pwcache_setgroupent = a_setgroupent;
      _pwcache_endgrent = a_endgrent;
      _pwcache_getgrnam = a_getgrnam;
      _pwcache_getgrgid = a_getgrgid;

      return (0);
}


#ifdef TEST_PWCACHE

struct passwd *
test_getpwnam(const char *name)
{
      static struct passwd foo;

      memset(&foo, 0, sizeof(foo));
      if (strcmp(name, "toor") == 0) {
            foo.pw_uid = 666;
            return &foo;
      }
      return (getpwnam(name));
}

int
main(int argc, char *argv[])
{
      uid_t u;
      int   r, i;

      printf("pass 1 (default userdb)\n");
      for (i = 1; i < argc; i++) {
            printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
                i, pwopn, usrtb_fail, usrtb);
            r = uid_from_user(argv[i], &u);
            if (r == -1)
                  printf("  uid_from_user %s: failed\n", argv[i]);
            else
                  printf("  uid_from_user %s: %d\n", argv[i], u);
      }
      printf("pass 1 finish: pwopn %d usrtb_fail %d usrtb %p\n",
                pwopn, usrtb_fail, usrtb);

      puts("");
      printf("pass 2 (replacement userdb)\n");
      printf("pwcache_userdb returned %d\n",
          pwcache_userdb(setpassent, test_getpwnam, getpwuid));
      printf("pwopn %d usrtb_fail %d usrtb %p\n", pwopn, usrtb_fail, usrtb);

      for (i = 1; i < argc; i++) {
            printf("i: %d, pwopn %d usrtb_fail %d usrtb %p\n",
                i, pwopn, usrtb_fail, usrtb);
            u = -1;
            r = uid_from_user(argv[i], &u);
            if (r == -1)
                  printf("  uid_from_user %s: failed\n", argv[i]);
            else
                  printf("  uid_from_user %s: %d\n", argv[i], u);
      }
      printf("pass 2 finish: pwopn %d usrtb_fail %d usrtb %p\n",
                pwopn, usrtb_fail, usrtb);

      puts("");
      printf("pass 3 (null pointers)\n");
      printf("pwcache_userdb returned %d\n",
          pwcache_userdb(NULL, NULL, NULL));

      return (0);
}
#endif      /* TEST_PWCACHE */
#endif      /* !HAVE_PWCACHE_USERDB */

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