#define PETSC_DESIRE_FEATURE_TEST_MACROS /* for getdomainname() */
/*
      Code for manipulating files.
*/
#include <petscsys.h>
#if defined(PETSC_HAVE_SYS_UTSNAME_H)
#include <sys/utsname.h>
#endif
#if defined(PETSC_HAVE_WINDOWS_H)
#include <windows.h>
#endif
#if defined(PETSC_HAVE_SYS_SYSTEMINFO_H)
#include <sys/systeminfo.h>
#endif
#if defined(PETSC_HAVE_UNISTD_H)
#include <unistd.h>
#endif
#if defined(PETSC_HAVE_NETDB_H)
#include <netdb.h>
#endif

/*@C
    PetscGetHostName - Returns the name of the host. This attempts to
    return the entire Internet name. It may not return the same name
    as MPI_Get_processor_name().

    Not Collective

    Input Parameter:
.   nlen - length of name

    Output Parameter:
.   name - contains host name.  Must be long enough to hold the name
           This is the fully qualified name, including the domain.

    Level: developer

   Fortran Version:
   In Fortran this routine has the format

$       character*(64) name
$       call PetscGetHostName(name,ierr)

.seealso: `PetscGetUserName()`, `PetscGetArchType()`
@*/
PetscErrorCode  PetscGetHostName(char name[],size_t nlen)
{
  char           *domain;
#if defined(PETSC_HAVE_UNAME) && !defined(PETSC_HAVE_GETCOMPUTERNAME)
  struct utsname utname;
#endif

  PetscFunctionBegin;
#if defined(PETSC_HAVE_GETCOMPUTERNAME)
  {
    size_t nnlen = nlen;
    GetComputerName((LPTSTR)name,(LPDWORD)(&nnlen));
  }
#elif defined(PETSC_HAVE_UNAME)
  uname(&utname);
  PetscCall(PetscStrncpy(name,utname.nodename,nlen));
#elif defined(PETSC_HAVE_GETHOSTNAME)
  gethostname(name,nlen);
#elif defined(PETSC_HAVE_SYSINFO_3ARG)
  sysinfo(SI_HOSTNAME,name,nlen);
#endif
  /* if there was not enough room then system call will not null terminate name */
  name[nlen-1] = 0;

  /* See if this name includes the domain */
  PetscCall(PetscStrchr(name,'.',&domain));
  if (!domain) {
    size_t l,ll;
    PetscCall(PetscStrlen(name,&l));
    if (l == nlen-1) PetscFunctionReturn(0);
    name[l++] = '.';
    name[l]   = 0;
#if defined(PETSC_HAVE_SYSINFO_3ARG)
    sysinfo(SI_SRPC_DOMAIN,name+l,nlen-l);
#elif defined(PETSC_HAVE_GETDOMAINNAME)
    PetscCheck(!getdomainname(name+l,nlen - l),PETSC_COMM_SELF,PETSC_ERR_SYS,"getdomainname()");
#endif
    /* check if domain name is not a dnsdomainname and nuke it */
    PetscCall(PetscStrlen(name,&ll));
    if (ll > 4) {
      const char *suffixes[] = {".edu",".com",".net",".org",".mil",NULL};
      PetscInt   index;
      PetscCall(PetscStrendswithwhich(name,suffixes,&index));
      if (!suffixes[index]) {
        PetscCall(PetscInfo(NULL,"Rejecting domainname, likely is NIS %s\n",name));
        name[l-1] = 0;
      }
    }
  }
  PetscFunctionReturn(0);
}