date and time created 82/08/25 21:54:05 by sam

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

/*      getnetent.c     4.1     82/08/25        */

#include <stdio.h>
#include <sys/socket.h>
#include <netdb.h>
#include <ctype.h>

#define MAXALIASES      35

static char *NETDB = "/usr/lib/networks";
static FILE *netf = NULL;
static char line[BUFSIZ+1];
static struct netent net;
static char *net_aliases[MAXALIASES];
static int stayopen = 0;
static unsigned long value();
static char *any();

setnetent(f)
       int f;
{
       if (netf == NULL)
               netf = fopen(NETDB, "r" );
       else
               rewind(netf);
       stayopen |= f;
}

endnetent()
{
       if (netf && !stayopen) {
               fclose(netf);
               netf = NULL;
       }
}

struct netent *
getnetent()
{
       char *p;
       register char *cp, **q;

       if (netf == NULL && (netf = fopen(NETDB, "r" )) == NULL)
               return (NULL);
again:
       p = fgets(line, BUFSIZ, netf);
       if (p == NULL)
               return (NULL);
       if (*p == '#')
               goto again;
       cp = any(p, "#\n");
       if (cp == NULL)
               goto again;
       *cp = '\0';
       net.n_name = p;
       cp = any(p, " \t");
       if (cp == NULL)
               goto again;
       *cp++ = '\0';
       while (*cp == ' ' || *cp == '\t')
               cp++;
       p = any(cp, " \t");
       if (p != NULL)
               *p++ = '\0';
       net.n_net = value(cp);
       net.n_aliases = net_aliases;
       q = net_aliases, cp = p;
       while (*cp) {
               if (*cp == ' ' || *cp == '\t') {
                       cp++;
                       continue;
               }
               if (q < &net_aliases[MAXALIASES - 1])
                       *q++ = cp;
               cp = any(cp, " \t");
               if (*cp != NULL)
                       *cp++ = '\0';
       }
       *q = NULL;
       return (&net);
}

static unsigned long
value(cp)
       register char *cp;
{
       register unsigned long val, base, n;
       register char c;
       unsigned long parts[4], *pp = parts;

again:
       val = 0; base = 10;
       if (*cp == '0')
               base = 8, cp++;
       if (*cp == 'x' || *cp == 'X')
               base = 16, cp++;
       while (c = *cp) {
               if (isdigit(c)) {
                       val = (val * base) + (c - '0');
                       cp++;
                       continue;
               }
               if (base == 16 && isxdigit(c)) {
                       val = (val << 4) + (c + 10 - (islower(c) ? 'a' : 'A'));
                       cp++;
                       continue;
               }
               break;
       }
       if (*cp == '.') {
               /*
                * Internet format:
                *      a.b.c.d
                *      a.b.c   (with c treated as 16-bits)
                *      a.b     (with b treated as 24 bits)
                */
               if (pp >= parts + 4)
                       return (-1);
               *pp++ = val, cp++;
               goto again;
       }
       if (*cp && !isspace(*cp))
               return (-1);
       n = pp - parts;
       if (n > 0) {
               if (n > 4)
                       return (-1);
               *pp++ = val; n++;
               val = parts[0];
               if (n > 1)
                       val <<= 24;
               if (n > 2)
                       val |= (parts[1] & 0xff) << 16;
               if (n > 3)
                       val |= (parts[2] & 0xff) << 8;
               if (n > 1)
                       val |= parts[n - 1];
#if vax || pdp11
               val = htonl(val);
#endif
       }
       return (val);
}

static char *
any(cp, match)
       register char *cp;
       char *match;
{
       register char *mp, c;

       while (c = *cp) {
               for (mp = match; *mp; mp++)
                       if (*mp == c)
                               return (cp);
               cp++;
       }
       return ((char *)0);
}