null pointer problems

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

/*      getnetent.c     4.5     82/11/14        */

#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 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 = inet_network(cp);
       net.n_addrtype = AF_INET;
       q = net.n_aliases = net_aliases;
       if (p != NULL) {
               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 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);
}