lib/util/system.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba system utilities
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Jeremy Allison 1998-2002
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "system/network.h"
  23 #include "system/filesys.h"
  24
  25 #undef malloc
  26
  27 /*
  28    The idea is that this file will eventually have wrappers around all
  29    important system calls in samba. The aims are:
  30
  31    - to enable easier porting by putting OS dependent stuff in here
  32
  33    - to allow for hooks into other "pseudo-filesystems"
  34
  35    - to allow easier integration of things like the japanese extensions
  36
  37    - to support the philosophy of Samba to expose the features of
  38      the OS within the SMB model. In general whatever file/printer/variable
  39      expansions/etc make sense to the OS should be acceptable to Samba.
  40 */
  41
  42 /*******************************************************************
  43  A wrapper for memalign
  44 ********************************************************************/
  45
  46 void *sys_memalign( size_t align, size_t size )
  47 {
  48 #if defined(HAVE_POSIX_MEMALIGN)
  49         void *p = NULL;
  50         int ret = posix_memalign( &p, align, size );
  51         if ( ret == 0 )
  52                 return p;
  53
  54         return NULL;
  55 #elif defined(HAVE_MEMALIGN)
  56         return memalign( align, size );
  57 #else
  58         /* On *BSD systems memaligns doesn't exist, but memory will
  59          * be aligned on allocations of > pagesize. */
  60 #if defined(SYSCONF_SC_PAGESIZE)
  61         size_t pagesize = (size_t)sysconf(_SC_PAGESIZE);
  62 #elif defined(HAVE_GETPAGESIZE)
  63         size_t pagesize = (size_t)getpagesize();
  64 #else
  65         size_t pagesize = (size_t)-1;
  66 #endif
  67         if (pagesize == (size_t)-1) {
  68                 DEBUG(0,("memalign functionalaity not available on this platform!\n"));
  69                 return NULL;
  70         }
  71         if (size < pagesize) {
  72                 size = pagesize;
  73         }
  74         return malloc(size);
  75 #endif
  76 }
  77
  78 /**************************************************************************
  79 A wrapper for gethostbyname() that tries avoids looking up hostnames
  80 in the root domain, which can cause dial-on-demand links to come up for no
  81 apparent reason.
  82 ****************************************************************************/
  83
  84 _PUBLIC_ struct hostent *sys_gethostbyname(const char *name)
  85 {
  86 #ifdef REDUCE_ROOT_DNS_LOOKUPS
  87         char query[256], hostname[256];
  88         char *domain;
  89
  90         /* Does this name have any dots in it? If so, make no change */
  91
  92         if (strchr(name, '.'))
  93                 return(gethostbyname(name));
  94
  95         /* Get my hostname, which should have domain name
  96                 attached. If not, just do the gethostname on the
  97                 original string.
  98         */
  99
 100         gethostname(hostname, sizeof(hostname) - 1);
 101         hostname[sizeof(hostname) - 1] = 0;
 102         if ((domain = strchr(hostname, '.')) == NULL)
 103                 return(gethostbyname(name));
 104
 105         /* Attach domain name to query and do modified query.
 106                 If names too large, just do gethostname on the
 107                 original string.
 108         */
 109
 110         if((strlen(name) + strlen(domain)) >= sizeof(query))
 111                 return(gethostbyname(name));
 112
 113         slprintf(query, sizeof(query)-1, "%s%s", name, domain);
 114         return(gethostbyname(query));
 115 #else /* REDUCE_ROOT_DNS_LOOKUPS */
 116         return(gethostbyname(name));
 117 #endif /* REDUCE_ROOT_DNS_LOOKUPS */
 118 }
 119
 120 _PUBLIC_ struct in_addr sys_inet_makeaddr(int net, int host)
 121 {
 122         struct in_addr in;
 123         struct in_addr in2;
 124         in = inet_makeaddr(net, host);
 125         in2.s_addr = in.s_addr;
 126         return in2;
 127 }
 128
 129 /**************************************************************************
 130  Wrapper for fork. Ensures we clear our pid cache.
 131 ****************************************************************************/
 132
 133 static pid_t mypid = (pid_t)-1;
 134
 135 _PUBLIC_ pid_t sys_fork(void)
 136 {
 137         pid_t forkret = fork();
 138
 139         if (forkret == (pid_t)0) {
 140                 /* Child - reset mypid so sys_getpid does a system call. */
 141                 mypid = (pid_t) -1;
 142         }
 143
 144         return forkret;
 145 }
 146
 147 /**************************************************************************
 148  Wrapper for getpid. Ensures we only do a system call *once*.
 149 ****************************************************************************/
 150
 151 _PUBLIC_ pid_t sys_getpid(void)
 152 {
 153         if (mypid == (pid_t)-1)
 154                 mypid = getpid();
 155
 156         return mypid;
 157 }
 158
 159
 160 _PUBLIC_ int sys_getpeereid( int s, uid_t *uid)
 161 {
 162 #if defined(HAVE_PEERCRED)
 163         struct ucred cred;
 164         socklen_t cred_len = sizeof(struct ucred);
 165         int ret;
 166
 167         ret = getsockopt(s, SOL_SOCKET, SO_PEERCRED, (void *)&cred, &cred_len);
 168         if (ret != 0) {
 169                 return -1;
 170         }
 171
 172         if (cred_len != sizeof(struct ucred)) {
 173                 errno = EINVAL;
 174                 return -1;
 175         }
 176
 177         *uid = cred.uid;
 178         return 0;
 179 #else
 180 #if defined(HAVE_GETPEEREID)
 181         gid_t gid;
 182         return getpeereid(s, uid, &gid);
 183 #endif
 184         errno = ENOSYS;
 185         return -1;
 186 #endif
 187 }
 188
 189 _PUBLIC_ int sys_getnameinfo(const struct sockaddr *psa,
 190                              int salen,
 191                              char *host,
 192                              size_t hostlen,
 193                              char *service,
 194                              size_t servlen,
 195                              int flags)
 196 {
 197         /*
 198          * For Solaris we must make sure salen is the
 199          * correct length for the incoming sa_family.
 200          */
 201
 202         if (salen == sizeof(struct sockaddr_storage)) {
 203                 salen = sizeof(struct sockaddr_in);
 204 #if defined(HAVE_IPV6)
 205                 if (psa->sa_family == AF_INET6) {
 206                         salen = sizeof(struct sockaddr_in6);
 207                 }
 208 #endif
 209         }
 210         return getnameinfo(psa, salen, host, hostlen, service, servlen, flags);
 211 }
 212
 213 _PUBLIC_ int sys_connect(int fd, const struct sockaddr * addr)
 214 {
 215         socklen_t salen = (socklen_t)-1;
 216
 217         if (addr->sa_family == AF_INET) {
 218             salen = sizeof(struct sockaddr_in);
 219         } else if (addr->sa_family == AF_UNIX) {
 220             salen = sizeof(struct sockaddr_un);
 221         }
 222 #if defined(HAVE_IPV6)
 223         else if (addr->sa_family == AF_INET6) {
 224             salen = sizeof(struct sockaddr_in6);
 225         }
 226 #endif
 227
 228         return connect(fd, addr, salen);
 229 }
 230