made sethostfile work with gethostbyname and gethostbyaddr

[unix-history] / usr / src / lib / libc / net / gethostnamadr.c

/*      gethostnamadr.c 4.7     85/01/16        */

#include <stdio.h>
#include <netdb.h>
#include <sys/file.h>
#include <ndbm.h>

#define MAXALIASES      35

static char HOSTDB[] = "/etc/hosts";
DBM *_host_db = (DBM *)NULL;
static struct hostent host;
static char *host_aliases[MAXALIASES];
static char hostbuf[BUFSIZ+1];
int _host_stayopen;     /* set by sethostent(), cleared by endhostent() */

static struct hostent *
fetchhost(key)
       datum key;
{
       register char *cp, *tp, **ap;
       register int naliases;

       if (key.dptr == 0)
               return ((struct hostent *)NULL);
       key = dbm_fetch(_host_db, key);
       if (key.dptr == 0)
               return ((struct hostent *)NULL);
       cp = key.dptr;
       tp = hostbuf;
       host.h_name = tp;
       while (*tp++ = *cp++)
               ;
       naliases = *(int *)cp; cp += sizeof (int);
       for (ap = host_aliases; naliases > 0; naliases--) {
               *ap++ = tp;
               while (*tp++ = *cp++)
                       ;
       }
       *ap = (char *)NULL;
       host.h_aliases = host_aliases;
       bcopy(cp, (char *)&host.h_addrtype, sizeof (int));
       cp += sizeof (int);
       bcopy(cp, (char *)&host.h_length, sizeof (int));
       cp += sizeof (int);
       host.h_addr = tp;
       bcopy(cp, tp, host.h_length);
       return (&host);
}

struct hostent *
gethostbyname(nam)
       char *nam;
{
       datum key;
       register struct hostent *hp;

       if ((_host_db == (DBM *)NULL)
         && ((_host_db = dbm_open(HOSTDB, O_RDONLY)) == (DBM *)NULL))
               return ((struct hostent *)NULL);
       key.dptr = nam;
       key.dsize = strlen(nam);
       hp = fetchhost(key);
       if (!_host_stayopen) {
               dbm_close(_host_db);
               _host_db = (DBM *)NULL;
       }
       return (hp);
}

struct hostent *
gethostbyaddr(addr, length)
       char *addr;
       int length;
{
       datum key;
       register struct hostent *hp;

       if ((_host_db == (DBM *)NULL)
         && ((_host_db = dbm_open(HOSTDB, O_RDONLY)) == (DBM *)NULL))
               return ((struct hostent *)NULL);
       key.dptr = addr;
       key.dsize = length;
       hp = fetchhost(key);
       if (!_host_stayopen) {
               dbm_close(_host_db);
               _host_db = (DBM *)NULL;
       }
       return (hp);
}