source: trunk/server/lib/util/system.c

/* 
   Unix SMB/CIFS implementation.
   Samba system utilities
   Copyright (C) Andrew Tridgell 1992-1998
   Copyright (C) Jeremy Allison 1998-2002
   
   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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "system/network.h"
#include "system/filesys.h"

/*
   The idea is that this file will eventually have wrappers around all
   important system calls in samba. The aims are:

   - to enable easier porting by putting OS dependent stuff in here

   - to allow for hooks into other "pseudo-filesystems"

   - to allow easier integration of things like the japanese extensions

   - to support the philosophy of Samba to expose the features of
     the OS within the SMB model. In general whatever file/printer/variable
     expansions/etc make sense to the OS should be acceptable to Samba.
*/

/**************************************************************************
A wrapper for gethostbyname() that tries avoids looking up hostnames 
in the root domain, which can cause dial-on-demand links to come up for no
apparent reason.
****************************************************************************/

_PUBLIC_ struct hostent *sys_gethostbyname(const char *name)
{
#ifdef REDUCE_ROOT_DNS_LOOKUPS
        char query[256], hostname[256];
        char *domain;

        /* Does this name have any dots in it? If so, make no change */

        if (strchr(name, '.'))
                return(gethostbyname(name));

        /* Get my hostname, which should have domain name 
                attached. If not, just do the gethostname on the
                original string. 
        */

        gethostname(hostname, sizeof(hostname) - 1);
        hostname[sizeof(hostname) - 1] = 0;
        if ((domain = strchr(hostname, '.')) == NULL)
                return(gethostbyname(name));

        /* Attach domain name to query and do modified query.
                If names too large, just do gethostname on the
                original string.
        */

        if((strlen(name) + strlen(domain)) >= sizeof(query))
                return(gethostbyname(name));

        slprintf(query, sizeof(query)-1, "%s%s", name, domain);
        return(gethostbyname(query));
#else /* REDUCE_ROOT_DNS_LOOKUPS */
        return(gethostbyname(name));
#endif /* REDUCE_ROOT_DNS_LOOKUPS */
}

_PUBLIC_ struct in_addr sys_inet_makeaddr(int net, int host)
{
        struct in_addr in;
        struct in_addr in2;
        in = inet_makeaddr(net, host);
        in2.s_addr = in.s_addr;
        return in2;
}

/**************************************************************************
 Wrapper for fork. Ensures we clear our pid cache.
****************************************************************************/

static pid_t mypid = (pid_t)-1;

_PUBLIC_ pid_t sys_fork(void)
{
        pid_t forkret = fork();

        if (forkret == (pid_t)0) {
                /* Child - reset mypid so sys_getpid does a system call. */
                mypid = (pid_t) -1;
        }

        return forkret;
}

/**************************************************************************
 Wrapper for getpid. Ensures we only do a system call *once*.
****************************************************************************/

_PUBLIC_ pid_t sys_getpid(void)
{
        if (mypid == (pid_t)-1)
                mypid = getpid();

        return mypid;
}


_PUBLIC_ int sys_getpeereid( int s, uid_t *uid)
{
#if defined(HAVE_PEERCRED)
        struct ucred cred;
        socklen_t cred_len = sizeof(struct ucred);
        int ret;

        ret = getsockopt(s, SOL_SOCKET, SO_PEERCRED, (void *)&cred, &cred_len);
        if (ret != 0) {
                return -1;
        }

        if (cred_len != sizeof(struct ucred)) {
                errno = EINVAL;
                return -1;
        }

        *uid = cred.uid;
        return 0;
#else
#if defined(HAVE_GETPEEREID)
        gid_t gid;
        return getpeereid(s, uid, &gid);
#endif
        errno = ENOSYS;
        return -1;
#endif
}

_PUBLIC_ int sys_getnameinfo(const struct sockaddr *psa,
                             int salen,
                             char *host,
                             size_t hostlen,
                             char *service,
                             size_t servlen,
                             int flags)
{
        /*
         * For Solaris we must make sure salen is the
         * correct length for the incoming sa_family.
         */

        if (salen == sizeof(struct sockaddr_storage)) {
                salen = sizeof(struct sockaddr_in);
#if defined(HAVE_IPV6)
                if (psa->sa_family == AF_INET6) {
                        salen = sizeof(struct sockaddr_in6);
                }
#endif
        }
        return getnameinfo(psa, salen, host, hostlen, service, servlen, flags);
}

_PUBLIC_ int sys_connect(int fd, const struct sockaddr * addr)
{
        socklen_t salen = (socklen_t)-1;

        if (addr->sa_family == AF_INET) {
            salen = sizeof(struct sockaddr_in);
        } else if (addr->sa_family == AF_UNIX) {
            salen = sizeof(struct sockaddr_un);
        }
#if defined(HAVE_IPV6)
        else if (addr->sa_family == AF_INET6) {
            salen = sizeof(struct sockaddr_in6);
        }
#endif

        return connect(fd, addr, salen);
}