4 files changed, 146 insertions, 7 deletions

diff --git a/contrib/Makefile.am b/contrib/Makefile.am
index f42fb684d..150e47ff0 100644
--- a/contrib/Makefile.am
+++ b/contrib/Makefile.am
@@ -53,6 +53,7 @@ EXTRA_DIST = \
  conf/gnunet/gnunet-user.conf \
  conf/nss/nssswitch.conf \
  conf/wireshark/wireshark.lua \
+ gnunet.m4 \
  $(PACKAGES_FILES) \
  $(INITD_FILES) \
  Makefile.inc \
@@ -77,3 +78,6 @@ test_gnunet_prefix_LDADD = \
   $(LTLIBICONV) \
   $(GN_LIBINTL) \
   $(LIBLTDL) -lunistring $(XLIB)
+
+aclocaldir = $(datadir)/aclocal
+aclocal_DATA = gnunet.m4
diff --git a/contrib/gnunet.m4 b/contrib/gnunet.m4
new file mode 100644
index 000000000..6d9332db3
--- /dev/null
+++ b/contrib/gnunet.m4
@@ -0,0 +1,72 @@
+# Autoconf macro for working with GNUnet
+# This file is in the public domain.
+#
+# AM_PATH_GNUNET([MINIMUM-VERSION = 0.15.3, [ACTION-IF-FOUND, [ACTION-IF-NOT-FOUND]]])
+# Find the GNUnet installation, either automatically or through the
+# --with-gnunet-prefix flag
+#
+# This macro runs the pkg-config and, if needed, the gnunet-config tool
+# provided by GNUnet itself.
+#
+# The gnunet-config tool can be overridden by setting the GNUNET_CONFIG
+# variable before executing the configure script.
+#
+# The variables GNUNET_CFLAGS and GNUNET_LIBS will be set to appropriate
+# values and are made available to Automake.
+AC_DEFUN([AM_PATH_GNUNET],
+[AC_ARG_WITH([gnunet-prefix],
+             [AS_HELP_STRING([--with-gnunet-prefix=PATH],
+                             [PATH to the GNUnet installation])],
+             [gnunet_prefix="$withval"],
+             [gnunet_prefix=""])
+ AC_ARG_ENABLE([debug-log],
+               [AS_HELP_STRING([--disable-debug-log],
+                               [Disable all DEBUG-level logging])],
+               [],
+               [enable_debug_log=yes])
+ AC_ARG_VAR([GNUNET_CONFIG],[The gnunet-config tool])
+ min_gnunet_version=m4_if([$1], ,0.15.3,$1)
+ # Make sure the specified version is at least the version with
+ # the features required to use this macro
+ AS_VERSION_COMPARE([$min_gnunet_version],[0.15.3],
+                    [AC_MSG_WARN([The specified GNUnet version $min_gnunet_version is too old.])
+                     AC_MSG_WARN([The minimum version has been set to 0.15.3])
+                     min_gnunet_version="0.15.3"])
+ AS_IF([test "x${GNUNET_CONFIG+set}" != "xset"],
+       [PKG_CHECK_MODULES([GNUNET],[gnunetutil >= $min_gnunet_version],
+                          [gnunet_pkgconfig=yes],[gnunet_pkgconfig=no])
+        AS_IF([test "x$gnunet_pkgconfig" = "xno" && test "x$gnunet_prefix" != "x"],
+              [gnunet_PATH="$PATH"
+               AS_IF([test "x$prefix" != "xNONE"],
+                     [gnunet_PATH="$prefix/bin${PATH_SEPARATOR}$prefix/usr/bin"])
+               AC_PATH_PROG([GNUNET_CONFIG],[gnunet-config],[no],[$gnunet_PATH])
+               AS_UNSET([gnunet_PATH])],
+              [GNUNET_CONFIG="pkg-config gnunetutil"])])
+ AC_MSG_CHECKING([if GNUnet version is >= $min_gnunet_version])
+ gnunet_result=no
+ AS_IF([test "x$GNUNET_CONFIG" != "xno" && test -n "$GNUNET_CONFIG"],
+       [gnunet_version=`$GNUNET_CONFIG --version | tr ' ' '\n' | sed -n '2p'`
+        AS_VERSION_COMPARE([$gnunet_version],[$min_gnunet_version],
+                           [gnunet_result=no],
+                           [gnunet_result=yes],
+                           [gnunet_result=yes])
+        AS_UNSET([gnunet_version])])
+ AS_IF([test "x$gnunet_result" != "xyes"],
+       [AC_MSG_RESULT([no])
+        m4_if([$3], ,:,[$3])],
+       [AC_MSG_RESULT([yes])
+        m4_if([$2], ,:,[$2])
+        AC_CHECK_HEADERS([sys/socket.h netinet/in.h byteswap.h])
+        AS_IF([test "x${GNUNET_CFLAGS+set}" != "xset"],
+              [GNUNET_CFLAGS=`$GNUNET_CONFIG --cflags`
+              AC_SUBST([GNUNET_CFLAGS])])
+        AS_IF([test "x${GNUNET_LIBS+set}" != "xset"],
+              [GNUNET_LIBS=`$GNUNET_CONFIG --libs`
+               AC_SUBST([GNUNET_LIBS])])
+        AS_IF([test "x$enable_debug_log" = "xno"],
+              [AC_DEFINE([GNUNET_EXTRA_LOGGING],
+                         [0],
+                         [0 if debug messages should be culled])])])
+ AS_UNSET([gnunet_result])
+ AS_UNSET([min_gnunet_version])
+])
diff --git a/doc/man/gnunet-config.1 b/doc/man/gnunet-config.1
index 03f180c29..c749c03b5 100644
--- a/doc/man/gnunet-config.1
+++ b/doc/man/gnunet-config.1
@@ -26,33 +26,44 @@
 .Os
 .Sh NAME
 .Nm gnunet-config
-.Nd manipulate GNUnet configuration files
+.Nd manipulate GNUnet configuration files and provide informations on how GNUnet was built
 .Sh SYNOPSIS
 .Nm
 .Op Fl b Ar BACKEND | Fl -supported-backend= Ns Ar BACKEND
+.Op Fl C | -cflags
 .Op Fl c Ar FILENAME | Fl -config= Ns Ar FILENAME
+.Op Fl F | -full
 .Op Fl f | -filename
 .Op Fl h | -help
+.Op Fl j | -libs
 .Op Fl L Ar LOGLEVEL | Fl -loglevel= Ns Ar LOGLEVEL
 .Op Fl o Ar OPTION | Fl -option= Ns Ar OPTION
+.Op Fl p | -prefix
+.Op Fl r | -rewrite
 .Op Fl S |-list-sections
 .Op Fl s Ar SECTION | Fl -section= Ns Ar SECTION
 .Op Fl V Ar VALUE | Fl -value Ar VALUE
 .Op Fl v | -version
-.Op Fl r | -rewrite
-.Op Fl F | -full
 .Sh DESCRIPTION
 .Nm
 can be used to read or modify GNUnet configuration files.
+It can also provide informations to properly build applications on top of
+GNUnet, like appropriate values for CFLAGS or the installation prefix.
 .Bl -tag -width indent
 .It Fl b Ar BACKEND | Fl -supported-backend= Ns Ar BACKEND
 Tests whether the specified BACKEND is supported by the current installation.  The backend must match the name of a plugin, e.g. "namestore_postgres" for the Postgres database backend of the "NAMESTORE" service. If the BACKEND is supported, gnunet-config will return a status code of 0 (success), otherwise 77 (unsupported).  When this option is specified, no other options may be specified. Specifying this option together with other options will cause gnunet-config to return a status code of 1 (error).
+.It Fl C | -cflags
+Print an appropriate value for CFLAGS to compile applications on top of GNUnet.
 .It Fl c Ar FILENAME | Fl -config= Ns Ar FILENAME
 Use the configuration file FILENAME.
+.It Fl F | -full
+Write the full configuration, not just the deltas to the defaults.
 .It Fl f | -filename
 Try to perform expansions as if the option values represent filenames (will also be applied even if the option is not really a filename).
 .It Fl h | -help
 Print short help on options.
+.It Fl j | -libs
+Print an appropriate value for LIBS to compile applications on top of GNUnet.
 .It Fl L Ar LOGLEVEL | Fl -loglevel= Ns Ar LOGLEVEL
 Use LOGLEVEL for logging.
 Valid values are DEBUG, INFO, WARNING and ERROR.
@@ -60,6 +71,10 @@ Valid values are DEBUG, INFO, WARNING and ERROR.
 Which configuration option should be accessed or edited.
 Required to set a value.
 If not given, all values of a given section will be printed in the format "OPTION = VALUE".
+.It Fl p | -prefix
+Print GNUnet's installation prefix (for example /usr/local.)
+.It Fl r | -rewrite
+Write the configuration to file, even if it did not change.
 .It Fl S |-list-sections
 List available configuration sections for use with --section.
 .It Fl s Ar SECTION | Fl -section= Ns Ar SECTION
@@ -70,10 +85,6 @@ Configuration value to store in the given section under the given option.
 Must only be given together with -s and -o options.
 .It Fl v | -version
 Print GNUnet version number.
-.It Fl r | -rewrite
-Write the configuration to file, even if it did not change.
-.It Fl F | -full
-Write the full configuration, not just the deltas to the defaults.
 .El
 .Sh SEE ALSO
 The full documentation for gnunet is maintained as a Texinfo manual.
diff --git a/src/util/gnunet-config.c b/src/util/gnunet-config.c
index 797de0b0d..a195d6014 100644
--- a/src/util/gnunet-config.c
+++ b/src/util/gnunet-config.c
@@ -36,6 +36,23 @@ static char *backend_check;
 
 
 /**
+ * If printing the value of CFLAGS has been requested.
+ */
+static int cflags;
+
+/**
+ * If printing the value of LIBS has been requested.
+ */
+static int libs;
+
+/**
+ * If printing the value of PREFIX has been requested.
+ */
+static int prefix;
+
+
+/**
+ * Print each option in a given section.
  * Main task to run to perform operations typical for
  * gnunet-config as per the configuration settings
  * given in @a cls.
@@ -54,6 +71,26 @@ run (void *cls,
 {
   struct GNUNET_CONFIGURATION_ConfigSettings *cs = cls;
 
+  if (1 == cflags || 1 == libs || 1 == prefix)
+  {
+    char *prefixdir = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_PREFIX);
+    char *libdir = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_LIBDIR);
+    if (1 == cflags)
+    {
+      fprintf (stdout, "-I%sinclude\n", prefixdir);
+    }
+    if (1 == libs)
+    {
+      fprintf (stdout, "-L%s -lgnunetutil\n", libdir);
+    }
+    if (1 == prefix)
+    {
+      fprintf (stdout, "%s\n", prefixdir);
+    }
+    GNUNET_free (prefixdir);
+    GNUNET_free (libdir);
+    return;
+  }
   if (NULL != backend_check)
   {
     char *name;
@@ -97,6 +134,21 @@ main (int argc,
         gettext_noop (
           "test if the current installation supports the specified BACKEND"),
         &backend_check)),
+    GNUNET_GETOPT_option_flag ('C',
+                               "cflags",
+                               gettext_noop (
+                                 "Provide an appropriate value for CFLAGS to applications building on top of GNUnet"),
+                               &cflags),
+    GNUNET_GETOPT_option_flag ('j',
+                               "libs",
+                               gettext_noop (
+                                 "Provide an appropriate value for LIBS to applications building on top of GNUnet"),
+                               &libs),
+    GNUNET_GETOPT_option_flag ('p',
+                               "prefix",
+                               gettext_noop (
+                                 "Provide the path under which GNUnet was installed"),
+                               &prefix),
     GNUNET_CONFIGURATION_CONFIG_OPTIONS (&cs),
     GNUNET_GETOPT_OPTION_END
   };