New program "gethostip" that can be used to print out hexadecimal

ip addresses, among other things

diff --git a/gethostip.c b/gethostip.c
new file mode 100644 (file)
index 0000000..21131d7
--- /dev/null
+++ b/gethostip.c
@@ -0,0 +1,135 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2001 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
+ *   USA; either version 2 of the License, or (at your option) any later
+ *   version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * gethostip.c
+ *
+ * Small program to use gethostbyname() to print out a hostname in
+ * hex and/or dotted-quad notation
+ */
+
+#include <stdio.h>
+#include <netdb.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <sysexits.h>
+#define _GNU_SOURCE            /* For getopt_long */
+#include <getopt.h>
+
+const struct option options[] =
+{
+  { "hexadecimal", 0, NULL, 'x' },
+  { "decimal",     0, NULL, 'd' },
+  { "dotted-quad", 0, NULL, 'd' },
+  { "full-output", 0, NULL, 'f' },
+  { "name",        0, NULL, 'n' },
+  { "help",        0, NULL, 'h' },
+  { NULL, 0, NULL, 0 }
+};
+
+const char *program;
+
+void usage(int exit_code)
+{
+  fprintf(stderr, "Usage: %s [-dxnf] hostname/ip...\n", program);
+  exit(exit_code);
+}
+
+int main(int argc, char *argv[])
+{
+  int opt;
+  int output = 0;
+  int i;
+  char *sep;
+  char dotquad[16];
+  int err = 0;
+
+  struct hostent *host;
+
+  program = argv[0];
+
+  while ( (opt = getopt_long(argc, argv, "dxfnh", options, NULL)) != -1 ) {
+    switch ( opt ) {
+    case 'd':
+      output |= 2;             /* Decimal output */
+      break;
+    case 'x':
+      output |= 4;             /* Hexadecimal output */
+      break;
+    case 'n':
+      output |= 1;             /* Canonical name output */
+      break;
+    case 'f':
+      output = 7;              /* Full output */
+      break;
+    case 'h':
+      usage(0);
+      break;
+    default:
+      usage(EX_USAGE);
+      break;
+    }
+  }
+
+  if ( optind == argc )
+    usage(EX_USAGE);
+
+  if ( output == 0 )
+    output = 7;                        /* Default output */
+
+  for ( i = optind ; i < argc ; i++ ) {
+    sep = "";
+    host = gethostbyname(argv[i]);
+    if ( !host ) {
+      herror(argv[i]);
+      err = 1;
+      continue;
+    }
+
+    if ( host->h_addrtype != AF_INET || host->h_length != 4 ) {
+      fprintf(stderr, "%s: No IPv4 address associated with name\n", argv[i]);
+      err = 1;
+      continue;
+    }
+
+    if ( output & 1 ) {
+      printf("%s%s", sep, host->h_name);
+      sep = " ";
+    }
+
+    if ( output & 2 ) {
+      sprintf(dotquad, "%u.%u.%u.%u",
+             ((unsigned char *)host->h_addr)[0],
+             ((unsigned char *)host->h_addr)[1],
+             ((unsigned char *)host->h_addr)[2],
+             ((unsigned char *)host->h_addr)[3]);
+      printf("%s%s", sep, dotquad);
+      sep = " ";
+    }
+
+    if ( output & 4 ) {
+      unsigned long addr = 
+       (((unsigned char *)host->h_addr)[0] << 24UL) +
+       (((unsigned char *)host->h_addr)[1] << 16UL) +
+       (((unsigned char *)host->h_addr)[2] <<  8UL) +
+       (((unsigned char *)host->h_addr)[3]);
+
+      printf("%s%08lX", sep, addr);
+      sep = " ";
+    }
+
+    putchar('\n');
+  }
+
+  return err;
+}