81 lines
1.7 KiB
C
81 lines
1.7 KiB
C
/*
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* fqdn - print fully qualified domain name(s)
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*
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* resolve all host names given on the comman line and print their
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* fully qualified canonical names.
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*
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* If no argument is given, print the system's FQDN.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <netdb.h>
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#include "hstrerror.h"
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char cvs_id[] = "$Id: fqdn.c,v 1.5 2004-05-17 18:13:46 hjp Exp $";
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char *cmnd;
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void usage(void) {
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fprintf(stderr, "Usage: %s [hostname ...]\n", cmnd);
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exit(1);
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}
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int main(int argc, char **argv) {
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int i;
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int rc = 0;
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char hostname[256];
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char *fake_argv[] = { NULL, hostname, NULL };
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cmnd = argv[0];
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if (argc < 2) {
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if (gethostname(hostname, sizeof(hostname)) == -1) {
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fprintf(stderr, "%s: cannot get hostname: %s\n",
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cmnd, strerror(errno));
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exit(1);
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}
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argv = fake_argv;
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argc = 2;
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}
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for (i = 1; i < argc; i++) {
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struct hostent *he = gethostbyname(argv[i]);
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int found = 0;
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if (!he) {
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fprintf(stderr, "%s: cannot resolve %s: %s\n",
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cmnd, argv[i], hstrerror(h_errno));
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rc++;
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continue;
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}
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if (strchr(he->h_name, '.')) {
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printf("%s\n", he->h_name);
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found = 1;
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} else {
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char **a;
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fprintf(stderr, "Canonical name doesn't contain a dot.\n");
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fprintf(stderr, "Please shoot the administrator of this box.\n");
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fprintf(stderr, "In the mean time I try to find a suitable alias.\n");
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for (a = he->h_aliases; !found && *a; a++) {
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if (strchr(*a, '.')) {
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printf("%s\n", *a);
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found = 1;
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}
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}
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if (!found) {
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fprintf(stderr, "No alias, either. Consider more painful methods than shooting.\n");
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rc++;
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}
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}
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}
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return rc;
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}
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