Configure options

- `configure.ac`:
  - Add `--enable-warn-all`
  - Add `--with-extra-cflags`
  - Add `--with-extra-ldflags`
- `m4/`: Add download script and required m4s
- `grok_question()`: Remove usage of `strcpy()`
- `pcap_tcp_handler()`: Use `snprintf()`
- `printable_dnsname()`: Use `snprintf()`

.gitignore

@@ -33,3 +33,8 @@ build/
 config.h.in
 dsc-[0-9]*tar*
 src/test/*.dist
+m4/libtool.m4
+m4/ltoptions.m4
+m4/ltsugar.m4
+m4/ltversion.m4
+m4/lt~obsolete.m4

.travis.yml

@@ -1,18 +1,22 @@
+addons:
+  apt:
+    update: true
+    packages:
+    - libpcap-dev
+    - libproc-pid-file-perl
+    - libgeoip-dev
 language: c
 compiler:
   - clang
   - gcc
-before_install:
-  - sudo apt-get -qq update
-  - sudo apt-get install -y libpcap-dev libproc-pid-file-perl libgeoip-dev
 install: ./autogen.sh
 script:
-  - ./configure
+  - ./configure --enable-warn-all
   - make dist
   - tar zxvf *.tar.gz
   - cd dsc-*[0-9]
   - mkdir build
   - cd build
-  - ../configure
+  - ../configure --enable-warn-all
   - make
   - make test

Makefile.am

@@ -1,4 +1,4 @@
-ACLOCAL_AMFLAGS = -I src/pcap-thread/m4
+ACLOCAL_AMFLAGS = -I m4 -I src/pcap-thread/m4
 
 MAINTAINERCLEANFILES = $(srcdir)/Makefile.in \
     $(srcdir)/src/config.h.in~ \
@@ -8,6 +8,6 @@ SUBDIRS = src cron
 
 dist_doc_DATA = README.md CHANGES LICENSE UPGRADE.md
 
-EXTRA_DIST = doc ports autogen.sh .clang-format fmt.sh
+EXTRA_DIST = m4 doc ports autogen.sh .clang-format fmt.sh
 
 test: check

autogen.sh

@@ -1,3 +1,3 @@
 #!/bin/sh -e
 
-autoreconf --force --install --no-recursive --include=src/pcap-thread/m4
+autoreconf --force --install --no-recursive --include=m4 --include=src/pcap-thread/m4

configure.ac

@@ -43,6 +43,21 @@ AC_PROG_CC
 AM_PROG_CC_C_O
 AC_PROG_INSTALL
 
+# Check --enable-warn-all
+AC_ARG_ENABLE([warn-all], [AS_HELP_STRING([--enable-warn-all], [Enable all compiler warnings])], [AX_CFLAGS_WARN_ALL()])
+
+# Check --with-extra-cflags
+AC_ARG_WITH([extra-cflags], [AS_HELP_STRING([--with-extra-cflags=CFLAGS], [Add extra CFLAGS])], [
+  AC_MSG_NOTICE([appending extra CFLAGS... $withval])
+  AS_VAR_APPEND(CFLAGS, [" $withval"])
+])
+
+# Check --with-extra-ldflags
+AC_ARG_WITH([extra-ldflags], [AS_HELP_STRING([--with-extra-ldflags=CFLAGS], [Add extra LDFLAGS])], [
+  AC_MSG_NOTICE([appending extra LDFLAGS... $withval])
+  AS_VAR_APPEND(LDFLAGS, [" $withval"])
+])
+
 # pcap thread
 AC_ARG_ENABLE(threads,
     [AS_HELP_STRING([--enable-threads],

m4/ax_append_flag.m4

@@ -0,0 +1,71 @@
+# ===========================================================================
+#      https://www.gnu.org/software/autoconf-archive/ax_append_flag.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_APPEND_FLAG(FLAG, [FLAGS-VARIABLE])
+#
+# DESCRIPTION
+#
+#   FLAG is appended to the FLAGS-VARIABLE shell variable, with a space
+#   added in between.
+#
+#   If FLAGS-VARIABLE is not specified, the current language's flags (e.g.
+#   CFLAGS) is used.  FLAGS-VARIABLE is not changed if it already contains
+#   FLAG.  If FLAGS-VARIABLE is unset in the shell, it is set to exactly
+#   FLAG.
+#
+#   NOTE: Implementation based on AX_CFLAGS_GCC_OPTION.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Guido U. Draheim <[email protected]>
+#   Copyright (c) 2011 Maarten Bosmans <[email protected]>
+#
+#   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, 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
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 7
+
+AC_DEFUN([AX_APPEND_FLAG],
+[dnl
+AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_SET_IF
+AS_VAR_PUSHDEF([FLAGS], [m4_default($2,_AC_LANG_PREFIX[FLAGS])])
+AS_VAR_SET_IF(FLAGS,[
+  AS_CASE([" AS_VAR_GET(FLAGS) "],
+    [*" $1 "*], [AC_RUN_LOG([: FLAGS already contains $1])],
+    [
+     AS_VAR_APPEND(FLAGS,[" $1"])
+     AC_RUN_LOG([: FLAGS="$FLAGS"])
+    ])
+  ],
+  [
+  AS_VAR_SET(FLAGS,[$1])
+  AC_RUN_LOG([: FLAGS="$FLAGS"])
+  ])
+AS_VAR_POPDEF([FLAGS])dnl
+])dnl AX_APPEND_FLAG

m4/ax_cflags_warn_all.m4

@@ -0,0 +1,122 @@
+# ===========================================================================
+#    https://www.gnu.org/software/autoconf-archive/ax_cflags_warn_all.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CFLAGS_WARN_ALL   [(shellvar [,default, [A/NA]])]
+#   AX_CXXFLAGS_WARN_ALL [(shellvar [,default, [A/NA]])]
+#   AX_FCFLAGS_WARN_ALL  [(shellvar [,default, [A/NA]])]
+#
+# DESCRIPTION
+#
+#   Try to find a compiler option that enables most reasonable warnings.
+#
+#   For the GNU compiler it will be -Wall (and -ansi -pedantic) The result
+#   is added to the shellvar being CFLAGS, CXXFLAGS, or FCFLAGS by default.
+#
+#   Currently this macro knows about the GCC, Solaris, Digital Unix, AIX,
+#   HP-UX, IRIX, NEC SX-5 (Super-UX 10), Cray J90 (Unicos 10.0.0.8), and
+#   Intel compilers.  For a given compiler, the Fortran flags are much more
+#   experimental than their C equivalents.
+#
+#    - $1 shell-variable-to-add-to : CFLAGS, CXXFLAGS, or FCFLAGS
+#    - $2 add-value-if-not-found : nothing
+#    - $3 action-if-found : add value to shellvariable
+#    - $4 action-if-not-found : nothing
+#
+#   NOTE: These macros depend on AX_APPEND_FLAG.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Guido U. Draheim <[email protected]>
+#   Copyright (c) 2010 Rhys Ulerich <[email protected]>
+#
+#   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; 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
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 16
+
+AC_DEFUN([AX_FLAGS_WARN_ALL],[dnl
+AS_VAR_PUSHDEF([FLAGS],[_AC_LANG_PREFIX[]FLAGS])dnl
+AS_VAR_PUSHDEF([VAR],[ac_cv_[]_AC_LANG_ABBREV[]flags_warn_all])dnl
+AC_CACHE_CHECK([m4_ifval($1,$1,FLAGS) for maximum warnings],
+VAR,[VAR="no, unknown"
+ac_save_[]FLAGS="$[]FLAGS"
+for ac_arg dnl
+in "-warn all  % -warn all"   dnl Intel
+   "-pedantic  % -Wall"       dnl GCC
+   "-xstrconst % -v"          dnl Solaris C
+   "-std1      % -verbose -w0 -warnprotos" dnl Digital Unix
+   "-qlanglvl=ansi % -qsrcmsg -qinfo=all:noppt:noppc:noobs:nocnd" dnl AIX
+   "-ansi -ansiE % -fullwarn" dnl IRIX
+   "+ESlit     % +w1"         dnl HP-UX C
+   "-Xc        % -pvctl[,]fullmsg" dnl NEC SX-5 (Super-UX 10)
+   "-h conform % -h msglevel 2" dnl Cray C (Unicos)
+   #
+do FLAGS="$ac_save_[]FLAGS "`echo $ac_arg | sed -e 's,%%.*,,' -e 's,%,,'`
+   AC_COMPILE_IFELSE([AC_LANG_PROGRAM],
+                     [VAR=`echo $ac_arg | sed -e 's,.*% *,,'` ; break])
+done
+FLAGS="$ac_save_[]FLAGS"
+])
+AS_VAR_POPDEF([FLAGS])dnl
+AX_REQUIRE_DEFINED([AX_APPEND_FLAG])
+case ".$VAR" in
+     .ok|.ok,*) m4_ifvaln($3,$3) ;;
+   .|.no|.no,*) m4_default($4,[m4_ifval($2,[AX_APPEND_FLAG([$2], [$1])])]) ;;
+   *) m4_default($3,[AX_APPEND_FLAG([$VAR], [$1])]) ;;
+esac
+AS_VAR_POPDEF([VAR])dnl
+])dnl AX_FLAGS_WARN_ALL
+dnl  implementation tactics:
+dnl   the for-argument contains a list of options. The first part of
+dnl   these does only exist to detect the compiler - usually it is
+dnl   a global option to enable -ansi or -extrawarnings. All other
+dnl   compilers will fail about it. That was needed since a lot of
+dnl   compilers will give false positives for some option-syntax
+dnl   like -Woption or -Xoption as they think of it is a pass-through
+dnl   to later compile stages or something. The "%" is used as a
+dnl   delimiter. A non-option comment can be given after "%%" marks
+dnl   which will be shown but not added to the respective C/CXXFLAGS.
+
+AC_DEFUN([AX_CFLAGS_WARN_ALL],[dnl
+AC_LANG_PUSH([C])
+AX_FLAGS_WARN_ALL([$1], [$2], [$3], [$4])
+AC_LANG_POP([C])
+])
+
+AC_DEFUN([AX_CXXFLAGS_WARN_ALL],[dnl
+AC_LANG_PUSH([C++])
+AX_FLAGS_WARN_ALL([$1], [$2], [$3], [$4])
+AC_LANG_POP([C++])
+])
+
+AC_DEFUN([AX_FCFLAGS_WARN_ALL],[dnl
+AC_LANG_PUSH([Fortran])
+AX_FLAGS_WARN_ALL([$1], [$2], [$3], [$4])
+AC_LANG_POP([Fortran])
+])

m4/ax_require_defined.m4

@@ -0,0 +1,37 @@
+# ===========================================================================
+#    https://www.gnu.org/software/autoconf-archive/ax_require_defined.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_REQUIRE_DEFINED(MACRO)
+#
+# DESCRIPTION
+#
+#   AX_REQUIRE_DEFINED is a simple helper for making sure other macros have
+#   been defined and thus are available for use.  This avoids random issues
+#   where a macro isn't expanded.  Instead the configure script emits a
+#   non-fatal:
+#
+#     ./configure: line 1673: AX_CFLAGS_WARN_ALL: command not found
+#
+#   It's like AC_REQUIRE except it doesn't expand the required macro.
+#
+#   Here's an example:
+#
+#     AX_REQUIRE_DEFINED([AX_CHECK_LINK_FLAG])
+#
+# LICENSE
+#
+#   Copyright (c) 2014 Mike Frysinger <[email protected]>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 2
+
+AC_DEFUN([AX_REQUIRE_DEFINED], [dnl
+  m4_ifndef([$1], [m4_fatal([macro ]$1[ is not defined; is a m4 file missing?])])
+])dnl AX_REQUIRE_DEFINED

m4/dl.sh

@@ -0,0 +1,25 @@
+#!/bin/sh -e
+# Copyright (c) 2018, OARC, Inc.
+# All rights reserved.
+#
+# This file is part of dnsjit.
+#
+# dnsjit 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 3 of the License, or
+# (at your option) any later version.
+#
+# dnsjit is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with dnsjit.  If not, see <http://www.gnu.org/licenses/>.
+
+m4_files="ax_append_flag.m4 ax_cflags_warn_all.m4 ax_require_defined.m4"
+
+for ax in $m4_files; do
+  rm -f "$ax"
+  wget -O "$ax" "http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/$ax"
+done

src/dns_message.c

@@ -110,7 +110,7 @@ printable_dnsname(const char* name)
         } else {
             if (i + 3 > MAX_QNAME_SZ - 1)
                 break; /* expanded character would overflow buffer */
-            sprintf(buf + i, "%%%02x", (unsigned char)*name);
+            snprintf(buf + i, i - sizeof(buf) - 1, "%%%02x", (unsigned char)*name);
             i += 3;
         }
     }

src/dns_protocol.c

@@ -127,8 +127,10 @@ grok_question(const u_char* buf, int len, off_t offset, char* qname, unsigned sh
     x = rfc1035NameUnpack(buf, len, &offset, qname, MAX_QNAME_SZ);
     if (0 != x)
         return 0;
-    if ('\0' == *qname)
-        strcpy(qname, ".");
+    if ('\0' == *qname) {
+        *qname = '.';
+        *(qname + 1) = 0;
+    }
     /* XXX remove special characters from QNAME */
     while ((t = strchr(qname, '\n')))
         *t = ' ';

src/pcap.c

@@ -579,12 +579,13 @@ pcap_tcp_handler(const struct tcphdr* tcp, int len, void* udata)
 
     if (debug_flag > 1) {
         char* p = label;
+        *p = 0;
         inXaddr_ntop(&key.src_ip_addr, p, 128);
         p += strlen(p);
-        p += sprintf(p, ":%d ", key.sport);
+        p += snprintf(p, 32, ":%d ", key.sport);
         inXaddr_ntop(&key.dst_ip_addr, p, 128);
         p += strlen(p);
-        p += sprintf(p, ":%d ", key.dport);
+        snprintf(p, 32, ":%d ", key.dport);
         dfprintf(1, "handle_tcp: %s", label);
     }