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