ipif: Introduce eat_optionalstr (and make protocol optional)

[userv-utils.git] / ipif / service.c

diff --git a/ipif/service.c b/ipif/service.c
index 39994169ea567ea8cb53aff07d29c9741de92fed..b401a5cb39dd76a21d451548a91c87a90eacd398 100644 (file)
--- a/ipif/service.c
+++ b/ipif/service.c
@@ -30,11 +30,11 @@
  *
  *  The remaining arguments are supplied by the (untrusted) caller:
  *
- *  <local-addr>,<peer-addr>,<mtu>,<proto>
+ *  <local-addr>,<peer-addr>,<mtu>[,[<proto>]]
  *
- *      As for slattach.  Supported protocols are slip, cslip, and
- *      adaptive.  Alternatively, set to `debug' to print debugging info
- *      and exit.  <local-addr> is address of the interface to be created
+ *      As for slattach.  The only supported protocol is slip.
+ *      Alternatively, set to `debug' to print debugging info and
+ *      exit.  <local-addr> is address of the interface to be created
  *      on the local system; <peer-addr> is the address of the
  *      point-to-point peer.  They must be actual addresses (not
  *      hostnames).
@@ -48,9 +48,9 @@
  *      not supported).  If no additional routes are to be set up, use `-'
  *      or supply an empty argument.
  *
- * Each <config> item - whether a line file such as
- * /etc/userv/ipif-networks, or supplied on the service program
- * command line - is one of:
+ * Each <config> item - whether a line in a file such as
+ * /etc/userv/ipif-networks, or the single trusted argument supplied
+ * on the service program command line - is one of:
  *
  *   /<config-file-name>
  *   ./<config-file-name>
@@ -91,12 +91,17 @@
  * The service program should be run from userv with no-disconnect-hup.
  */
 /*
- * Copyright (C) 1999-2000,2003 Ian Jackson
  * This file is part of ipif, part of userv-utils
  *
+ * Copyright 1996-2013 Ian Jackson <ijackson@chiark.greenend.org.uk>
+ * Copyright 1998 David Damerell <damerell@chiark.greenend.org.uk>
+ * Copyright 1999,2003
+ *    Chancellor Masters and Scholars of the University of Cambridge
+ * Copyright 2010 Tony Finch <fanf@dotat.at>
+ *
  * This 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; either version 2 of the License, or
+ * the Free Software Foundation; either version 3 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful, but
@@ -105,10 +110,7 @@
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with userv-utils; if not, write to the Free Software
- * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * $Id$
+ * along with userv-utils; if not, see http://www.gnu.org/licenses/.
  */
 
 #include <stdio.h>
@@ -123,6 +125,7 @@
 #include <unistd.h>
 #include <stdint.h>
 #include <poll.h>
+#include <stddef.h>
 
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -321,6 +324,30 @@ static void eat_prefixmask(const char **argp, const char *what,
   if (len_r) *len_r= len;
 }
 
+static char *eat_optionalstr(const char **argp,
+                            const char *what,
+                            const char *def) {
+  ptrdiff_t len;
+  const char *start= *argp;
+  const char *comma= strchr(start, ',');
+  if (comma) {
+    len= comma - start;
+    *argp= comma + 1;
+  } else {
+    len= strlen(start);
+    *argp= start + len;
+  }
+  if (!len) {
+    start= def;
+    len= strlen(def);
+  }
+  char *r = malloc(len+1);
+  if (!r) sysfatal("malloc for command line string");
+  memcpy(r,start,len);
+  r[len]= 0;
+  return r;
+}
+
 static int addrnet_isin(unsigned long prefix, unsigned long mask,
                        unsigned long mprefix, unsigned long mmask) {
   return  !(~mask & mmask)  &&  (prefix & mmask) == mprefix;
@@ -543,12 +570,13 @@ static void parseargs(int argc, const char *const *argv) {
   peeraddr= eat_addr(&carg,"peer-addr", ",",0);
   mtu= eat_number(&carg,"mtu", 576,65536, ",",0);
   localallow= peerallow= 0;
-  
-  if (!strcmp(carg,"debug")) {
+
+  char *protostr = eat_optionalstr(&carg,"protocol","slip");
+  if (!strcmp(protostr,"debug")) {
     proto= 0;
   } else {
     for (cprotop= protos_ok;
-        (proto= *cprotop) && strcmp(proto,carg);
+        (proto= *cprotop) && strcmp(proto,protostr);
         cprotop++);
     if (!proto) fatal("invalid protocol");
   }
@@ -863,7 +891,7 @@ static void copydata(void) {
       r= read(0, input_buf + input_waiting, want);
       if (r>0) {
        input_waiting += r;
-       assert(input_waiting < sizeof(input_buf));
+       assert(input_waiting <= sizeof(input_buf));
        more_rx_data(input_buf, rx_packet_buf);
       } else if (r==0) {
        terminate(0);