File: resolve.c

package info (click to toggle)
krb5 1.17-3
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 52,868 kB
  • sloc: ansic: 305,285; exp: 13,345; cpp: 9,731; python: 8,948; makefile: 7,215; sh: 6,279; perl: 2,391; asm: 1,460; yacc: 1,005; awk: 396; csh: 147; xml: 135; lisp: 104; sed: 41
file content (165 lines) | stat: -rw-r--r-- 4,363 bytes parent folder | download | duplicates (6)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* tests/resolve/resolve.c */
/*
 * Copyright 1995 by the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  Furthermore if you modify this software you must label
 * your software as modified software and not distribute it in such a
 * fashion that it might be confused with the original M.I.T. software.
 * M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */

/*
 * A simple program to test the functionality of the resolver library.
 * It simply will try to get the IP address of the host, and then look
 * up the name from the address. If the resulting name does not contain the
 * domain name, then the resolve library is broken.
 *
 * Warning: It is possible to fool this program into thinking everything is
 * alright by a clever use of /etc/hosts - but this is better than nothing.
 *
 * Usage:
 *   resolve [hostname]
 *
 *   When invoked with no arguments, gethostname is used for the local host.
 *
 */

/* This program tests the resolve library and sees if it is broken... */

#include "autoconf.h"
#include <stdio.h>

#if STDC_HEADERS
#include <string.h>
#else
#ifndef HAVE_STRCHR
#define strchr index
#endif
char *strchr();
#endif

#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif

#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <netinet/in.h>
#include <netdb.h>

#ifndef MAXHOSTNAMELEN
# define MAXHOSTNAMELEN 256
#endif

int
main(argc, argv)
    int argc;
    char **argv;
{
    char myname[MAXHOSTNAMELEN+1];
    char *ptr, *fqdn;
    struct in_addr addrcopy;
    struct hostent *host;
    int quiet = 0;

    argc--; argv++;
    while (argc) {
        if ((strcmp(*argv, "--quiet") == 0) ||
            (strcmp(*argv, "-q") == 0)) {
            quiet++;
        } else
            break;
        argc--; argv++;
    }

    if (argc >= 1) {
        strncpy(myname, *argv, MAXHOSTNAMELEN);
    } else {
        if(gethostname(myname, MAXHOSTNAMELEN)) {
            perror("gethostname failure");
            exit(1);
        }
    }

    myname[MAXHOSTNAMELEN] = '\0';  /* for safety */

    /* Look up the address... */
    if (!quiet)
        printf("Hostname:  %s\n", myname);


    /* Set the hosts db to close each time - effectively rewinding file */
    sethostent(0);

    if((host = gethostbyname (myname)) == NULL) {
        fprintf(stderr,
                "Could not look up address for hostname '%s' - fatal\n",
                myname);
        exit(2);
    }

    fqdn = strdup(host->h_name);
    if (fqdn == NULL) {
        perror("strdup");
        exit(2);
    }

    ptr = host->h_addr_list[0];
#define UC(a) (((int)a)&0xff)
    if (!quiet)
        printf("Host address: %d.%d.%d.%d\n",
               UC(ptr[0]), UC(ptr[1]), UC(ptr[2]), UC(ptr[3]));

    memcpy(&addrcopy.s_addr, ptr, 4);

    /* Convert back to full name */
    if ((host = gethostbyaddr(&addrcopy.s_addr, 4, AF_INET)) == NULL) {
        if (!quiet)
            fprintf(stderr, "Error looking up IP address\n");
    } else {
        free(fqdn);
        fqdn = strdup(host->h_name);
        if (fqdn == NULL) {
            perror("strdup");
            exit (2);
        }
    }

    if (quiet)
        printf("%s\n", fqdn);
    else
        printf("FQDN: %s\n", fqdn);

    if (!quiet)
        printf("Resolve library appears to have passed the test\n");

    /* All ok */
    exit(0);

}