/* * fqdn - print fully qualified domain name(s) * * resolve all host names given on the comman line and print their * fully qualified canonical names. * * If no argument is given, print the system's FQDN. */ #include #include #include #include #include #include #include "hstrerror.h" char cvs_id[] = "$Id: fqdn.c,v 1.3 2002-08-14 19:06:39 hjp Exp $"; char *cmnd; void usage(void) { fprintf(stderr, "Usage: %s [hostname ...]\n", cmnd); exit(1); } int main(int argc, char **argv) { int i; int rc = 0; char hostname[256]; char *fake_argv[] = { NULL, hostname, NULL }; cmnd = argv[0]; if (argc < 2) { if (gethostname(hostname, sizeof(hostname)) == -1) { fprintf(stderr, "%s: cannot get hostname: %s\n", cmnd, strerror(errno)); exit(1); } argv = fake_argv; argc = 2; } for (i = 1; i < argc; i++) { struct hostent *he = gethostbyname(argv[i]); if (!he) { fprintf(stderr, "%s: cannot resolve %s: %s\n", argv[0], argv[i], hstrerror(h_errno)); rc++; continue; } printf("%s\n", he->h_name); } return rc; }