1  /* gethostname emulation for SysV and POSIX.1.
       2  
       3     Copyright (C) 1992, 2003, 2006, 2008-2022 Free Software Foundation, Inc.
       4  
       5     This file is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU Lesser General Public License as
       7     published by the Free Software Foundation; either version 2.1 of the
       8     License, or (at your option) any later version.
       9  
      10     This file is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13     GNU Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  /* David MacKenzie <djm@gnu.ai.mit.edu>
      19     Windows port by Simon Josefsson <simon@josefsson.org> */
      20  
      21  #include <config.h>
      22  
      23  #if !(defined _WIN32 && !defined __CYGWIN__)
      24  /* Unix API.  */
      25  
      26  /* Specification.  */
      27  #include <unistd.h>
      28  
      29  #ifdef HAVE_UNAME
      30  # include <sys/utsname.h>
      31  #endif
      32  
      33  #include <string.h>
      34  
      35  /* Put up to LEN chars of the host name into NAME.
      36     Null terminate it if the name is shorter than LEN.
      37     Return 0 if ok, -1 if error.  */
      38  
      39  #include <stddef.h>
      40  
      41  int
      42  gethostname (char *name, size_t len)
      43  {
      44  #ifdef HAVE_UNAME
      45    struct utsname uts;
      46  
      47    if (uname (&uts) == -1)
      48      return -1;
      49    if (len > sizeof (uts.nodename))
      50      {
      51        /* More space than we need is available.  */
      52        name[sizeof (uts.nodename)] = '\0';
      53        len = sizeof (uts.nodename);
      54      }
      55    strncpy (name, uts.nodename, len);
      56  #else
      57    strcpy (name, "");            /* Hardcode your system name if you want.  */
      58  #endif
      59    return 0;
      60  }
      61  
      62  #else
      63  /* Native Windows API.  Which primitive to choose?
      64     - gethostname() requires linking with -lws2_32.
      65     - GetComputerName() does not return the right kind of hostname.
      66     - GetComputerNameEx(ComputerNameDnsHostname,...) returns the right hostname,
      67       but it is hard to use portably:
      68         - It requires defining _WIN32_WINNT to at least 0x0500.
      69         - With mingw, it also requires
      70           "#define GetComputerNameEx GetComputerNameExA".
      71         - With older versions of mingw, none of the declarations are present at
      72           all, not even of the enum value ComputerNameDnsHostname.
      73     So we use gethostname().  Linking with -lws2_32 is the least evil.  */
      74  
      75  #define WIN32_LEAN_AND_MEAN
      76  /* Get winsock2.h. */
      77  #include <unistd.h>
      78  
      79  /* Get INT_MAX.  */
      80  #include <limits.h>
      81  
      82  /* Get set_winsock_errno. */
      83  #include "w32sock.h"
      84  
      85  #include "sockets.h"
      86  
      87  #undef gethostname
      88  
      89  int
      90  rpl_gethostname (char *name, size_t len)
      91  {
      92    int r;
      93  
      94    if (len > INT_MAX)
      95      len = INT_MAX;
      96    gl_sockets_startup (SOCKETS_1_1);
      97    r = gethostname (name, (int) len);
      98    if (r < 0)
      99      set_winsock_errno ();
     100  
     101    return r;
     102  }
     103  
     104  #endif