source: trunk-3.0/source/lib/util_pw.c@ 102

/* 
   Unix SMB/CIFS implementation.

   Safe versions of getpw* calls

   Copyright (C) Andrew Bartlett 2002
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

struct passwd *tcopy_passwd(TALLOC_CTX *mem_ctx, const struct passwd *from) 
{
        struct passwd *ret = TALLOC_P(mem_ctx, struct passwd);
        if (!ret) {
                return NULL;
        }
        ret->pw_name = talloc_strdup(ret, from->pw_name);
        ret->pw_passwd = talloc_strdup(ret, from->pw_passwd);
        ret->pw_uid = from->pw_uid;
        ret->pw_gid = from->pw_gid;
        ret->pw_gecos = talloc_strdup(ret, from->pw_gecos);
        ret->pw_dir = talloc_strdup(ret, from->pw_dir);
        ret->pw_shell = talloc_strdup(ret, from->pw_shell);
        return ret;
}

#define PWNAMCACHE_SIZE 4
static struct passwd **pwnam_cache = NULL;

static void init_pwnam_cache(void)
{
        if (pwnam_cache != NULL)
                return;

        pwnam_cache = TALLOC_ZERO_ARRAY(NULL, struct passwd *,
                                        PWNAMCACHE_SIZE);
        if (pwnam_cache == NULL) {
                smb_panic("Could not init pwnam_cache\n");
        }

        return;
}

void flush_pwnam_cache(void)
{
        TALLOC_FREE(pwnam_cache);
        pwnam_cache = NULL;
        init_pwnam_cache();
}

struct passwd *getpwnam_alloc(TALLOC_CTX *mem_ctx, const char *name)
{
        int i;

        struct passwd *temp;

        init_pwnam_cache();

        for (i=0; i<PWNAMCACHE_SIZE; i++) {
                if ((pwnam_cache[i] != NULL) && 
                    (strcmp(name, pwnam_cache[i]->pw_name) == 0)) {
                        DEBUG(10, ("Got %s from pwnam_cache\n", name));
                        return (struct passwd *)talloc_reference(mem_ctx, pwnam_cache[i]);
                }
        }

        temp = sys_getpwnam(name);
        
        if (!temp) {
#if 0
                if (errno == ENOMEM) {
                        /* what now? */
                }
#endif
                return NULL;
        }

        for (i=0; i<PWNAMCACHE_SIZE; i++) {
                if (pwnam_cache[i] == NULL)
                        break;
        }

        if (i == PWNAMCACHE_SIZE)
                i = rand() % PWNAMCACHE_SIZE;

        if (pwnam_cache[i] != NULL) {
                TALLOC_FREE(pwnam_cache[i]);
        }

        pwnam_cache[i] = tcopy_passwd(pwnam_cache, temp);
        if (pwnam_cache[i]!= NULL && mem_ctx != NULL) {
                return (struct passwd *)talloc_reference(mem_ctx, pwnam_cache[i]);
        }

        return tcopy_passwd(NULL, pwnam_cache[i]);
}

struct passwd *getpwuid_alloc(TALLOC_CTX *mem_ctx, uid_t uid) 
{
        struct passwd *temp;

        temp = sys_getpwuid(uid);
        
        if (!temp) {
#if 0
                if (errno == ENOMEM) {
                        /* what now? */
                }
#endif
                return NULL;
        }

        return tcopy_passwd(mem_ctx, temp);
}