minix/lib/ip/gethostent.c
2005-04-21 14:53:53 +00:00

168 lines
4 KiB
C
Executable file

/* gethostent() - Interface to /etc/hosts Author: Kees J. Bot
* 31 May 1999
*/
/* Prefix the functions defined here with underscores to distinguish them
* from the newer replacements in the resolver library.
*/
#define sethostent _sethostent
#define endhostent _endhostent
#define gethostent _gethostent
#define gethostbyname _gethostbyname
#define gethostbyaddr _gethostbyaddr
#define nil 0
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <net/gen/netdb.h>
#include <net/gen/in.h>
#include <net/gen/inet.h>
#include <net/gen/socket.h>
#define arraysize(a) (sizeof(a) / sizeof((a)[0]))
#define arraylimit(a) ((a) + arraysize(a))
#define isspace(c) ((unsigned) (c) <= ' ')
static char HOSTS[]= _PATH_HOSTS;
static char *hosts= HOSTS; /* Current hosts file. */
static FILE *hfp; /* Open hosts file. */
void sethostent(int stayopen)
/* Start search. (Same as ending it.) */
{
endhostent();
}
void endhostent(void)
/* End search and reinitialize. */
{
if (hfp != nil) {
fclose(hfp);
hfp= nil;
}
hosts= _PATH_HOSTS;
}
struct hostent *gethostent(void)
/* Return the next entry from the hosts files. */
{
static char line[256]; /* One line in a hosts file. */
static ipaddr_t addr; /* IP address found first on the line. */
static char *names[16]; /* Pointers to the words on the line. */
static char *addrs[2]= { /* List of IP addresses (just one.) */
(char *) &addr,
nil,
};
static struct hostent host = {
nil, /* h_name, will set to names[1]. */
names + 2, /* h_aliases, the rest of the names. */
AF_INET, /* h_addrtype */
sizeof(ipaddr_t), /* Size of an address in the address list. */
addrs, /* List of IP addresses. */
};
static char nexthosts[128]; /* Next hosts file to include. */
char *lp, **np;
int c;
for (;;) {
if (hfp == nil) {
/* No hosts file open, try to open the next one. */
if (hosts == 0) return nil;
if ((hfp= fopen(hosts, "r")) == nil) { hosts= nil; continue; }
}
/* Read a line. */
lp= line;
while ((c= getc(hfp)) != EOF && c != '\n') {
if (lp < arraylimit(line)) *lp++= c;
}
/* EOF? Then close and prepare for reading the next file. */
if (c == EOF) {
fclose(hfp);
hfp= nil;
hosts= nil;
continue;
}
if (lp == arraylimit(line)) continue;
*lp= 0;
/* Break the line up in words. */
np= names;
lp= line;
for (;;) {
while (isspace(*lp) && *lp != 0) lp++;
if (*lp == 0 || *lp == '#') break;
if (np == arraylimit(names)) break;
*np++= lp;
while (!isspace(*lp) && *lp != 0) lp++;
if (*lp == 0) break;
*lp++= 0;
}
if (np == arraylimit(names)) continue;
*np= nil;
/* Special "include file" directive. */
if (np == names + 2 && strcmp(names[0], "include") == 0) {
fclose(hfp);
hfp= nil;
hosts= nil;
if (strlen(names[1]) < sizeof(nexthosts)) {
strcpy(nexthosts, names[1]);
hosts= nexthosts;
}
continue;
}
/* At least two words, the first of which is an IP address. */
if (np < names + 2) continue;
if (!inet_aton((char *) names[0], &addr)) continue;
host.h_name= (char *) names[1];
return &host;
}
}
/* Rest kept in reserve, we probably never need 'em. */
#if XXX
struct hostent *gethostbyname(const char *name)
{
struct hostent *he;
char **pa;
char alias[256];
char *domain;
sethostent(0);
while ((he= gethostent()) != nil) {
if (strcasecmp(he->h_name, name) == 0) goto found;
domain= strchr(he->h_name, '.');
for (pa= he->h_aliases; *pa != nil; pa++) {
strcpy(alias, *pa);
if (domain != nil && strchr(alias, '.') == nil) {
strcat(alias, domain);
}
if (strcasecmp(alias, name) == 0) goto found;
}
}
found:
endhostent();
return he;
}
struct hostent *gethostbyaddr(const char *addr, int len, int type)
{
struct hostent *he;
sethostent(0);
while ((he= gethostent()) != nil) {
if (he->h_name[0] == '%') continue;
if (type == AF_INET && memcmp(he->h_addr, addr, len) == 0) break;
}
endhostent();
return he;
}
#endif