1 /* gethostent.c 4.5 83/01/02 */ 2 3 #include <stdio.h> 4 #include <sys/types.h> 5 #include <sys/socket.h> 6 #include <netdb.h> 7 #include <ctype.h> 8 9 /* 10 * Internet version. 11 */ 12 #define MAXALIASES 35 13 #define MAXADDRSIZE 14 14 15 static char HOSTDB[] = "/etc/hosts"; 16 static FILE *hostf = NULL; 17 static char line[BUFSIZ+1]; 18 static char hostaddr[MAXADDRSIZE]; 19 static struct hostent host; 20 static char *host_aliases[MAXALIASES]; 21 static int stayopen = 0; 22 static char *any(); 23 24 sethostent(f) 25 int f; 26 { 27 if (hostf == NULL) 28 hostf = fopen(HOSTDB, "r" ); 29 else 30 rewind(hostf); 31 stayopen |= f; 32 } 33 34 endhostent() 35 { 36 if (hostf && !stayopen) { 37 fclose(hostf); 38 hostf = NULL; 39 } 40 } 41 42 struct hostent * 43 gethostent() 44 { 45 char *p; 46 register char *cp, **q; 47 48 if (hostf == NULL && (hostf = fopen(HOSTDB, "r" )) == NULL) 49 return (NULL); 50 again: 51 if ((p = fgets(line, BUFSIZ, hostf)) == NULL) 52 return (NULL); 53 if (*p == '#') 54 goto again; 55 cp = any(p, "#\n"); 56 if (cp == NULL) 57 goto again; 58 *cp = '\0'; 59 cp = any(p, " \t"); 60 if (cp == NULL) 61 goto again; 62 *cp++ = '\0'; 63 /* THIS STUFF IS INTERNET SPECIFIC */ 64 host.h_addr = hostaddr; 65 *((u_long *)host.h_addr) = inet_addr(p); 66 host.h_length = sizeof (u_long); 67 host.h_addrtype = AF_INET; 68 while (*cp == ' ' || *cp == '\t') 69 cp++; 70 host.h_name = cp; 71 q = host.h_aliases = host_aliases; 72 cp = any(cp, " \t"); 73 if (cp != NULL) 74 *cp++ = '\0'; 75 while (cp && *cp) { 76 if (*cp == ' ' || *cp == '\t') { 77 cp++; 78 continue; 79 } 80 if (q < &host_aliases[MAXALIASES - 1]) 81 *q++ = cp; 82 cp = any(cp, " \t"); 83 if (cp != NULL) 84 *cp++ = '\0'; 85 } 86 *q = NULL; 87 return (&host); 88 } 89 90 static char * 91 any(cp, match) 92 register char *cp; 93 char *match; 94 { 95 register char *mp, c; 96 97 while (c = *cp) { 98 for (mp = match; *mp; mp++) 99 if (*mp == c) 100 return (cp); 101 cp++; 102 } 103 return ((char *)0); 104 } 105