introduce --with-rootprefix=DIR

Configure the location of the rootfs directories and use it
to find (/usr)/lib/modules and (/usr)/lib/modprobe.d.

Makefile.am

@@ -6,6 +6,7 @@ AM_MAKEFLAGS = --no-print-directory
 AM_CPPFLAGS = \
 	-include $(top_builddir)/config.h \
 	-I$(top_srcdir)/libkmod \
+	-DROOTPREFIX=\""$(rootprefix)"\" \
 	-DSYSCONFDIR=\""$(sysconfdir)"\" \
 	-DLIBEXECDIR=\""$(libexecdir)"\"
 

configure.ac

@@ -27,6 +27,11 @@ AC_C_BIGENDIAN
 
 required_private_libs=""
 
+AC_ARG_WITH([rootprefix],
+        AS_HELP_STRING([--with-rootprefix=DIR], [rootfs directory prefix for config files and kernel modules]),
+        [], [with_rootprefix=$prefix])
+AC_SUBST([rootprefix], [$with_rootprefix])
+
 AC_ARG_ENABLE([tools],
         AS_HELP_STRING([--disable-tools], [disable building tools that provide same functionality as module-init-tools @<:@default=enabled@:>@]),
 	[], enable_tools=yes)
@@ -147,6 +152,7 @@ AC_MSG_RESULT([
 	========
 
 	prefix:			${prefix}
+	rootprefix:		${rootprefix}
 	sysconfdir:		${sysconfdir}
 	libdir:			${libdir}
 	includedir:		${includedir}

libkmod/libkmod.c

@@ -60,8 +60,8 @@ static const char* index_files[] = {
 
 static const char *default_config_paths[] = {
 	"/run/modprobe.d",
-	"/etc/modprobe.d",
+	SYSCONFDIR "/modprobe.d",
-	"/lib/modprobe.d",
+	ROOTPREFIX "/lib/modprobe.d",
 	NULL
 };
 
@@ -159,7 +159,7 @@ static int log_priority(const char *priority)
 	return 0;
 }
 
-static const char *dirname_default_prefix = "/lib/modules";
+static const char *dirname_default_prefix = ROOTPREFIX "/lib/modules";
 
 static char *get_kernel_release(const char *dirname)
 {
@@ -188,12 +188,12 @@ static char *get_kernel_release(const char *dirname)
  * release the resources of the kmod library context.
  *
  * @dirname: what to consider as linux module's directory, if NULL
- *           defaults to /lib/modules/`uname -r`.
+ *           defaults to $rootprefix/lib/modules/`uname -r`.
  * @config_paths: ordered array of paths (directories or files) where
  *                to load from user-defined configuration parameters such as
  *                alias, blacklists, commands (install, remove). If
  *                NULL defaults to /run/modprobe.d, /etc/modprobe.d and
- *                /lib/modprobe.d. Give an empty vector if configuration should
+ *                $rootprefix/lib/modprobe.d. Give an empty vector if configuration should
  *                not be read. This array must be null terminated.
  *
  * Returns: a new kmod library context

tools/kmod-modinfo.c

@@ -320,7 +320,7 @@ static void help(const char *progname)
 		"\t-0, --null                  Use \\0 instead of \\n\n"
 		"\t-F, --field=FIELD           Print only provided FIELD\n"
 		"\t-k, --set-version=VERSION   Use VERSION instead of `uname -r`\n"
-		"\t-b, --basedir=DIR           Use DIR as filesystem root for /lib/modules\n"
+		"\t-b, --basedir=DIR           Use DIR as filesystem root for " ROOTPREFIX "/lib/modules\n"
 		"\t-V, --version               Show version\n"
 		"\t-h, --help                  Show this help\n",
 		progname);
@@ -402,7 +402,7 @@ int main(int argc, char *argv[])
 			}
 			kversion = u.release;
 		}
-		snprintf(dirname_buf, sizeof(dirname_buf), "%s/lib/modules/%s",
+		snprintf(dirname_buf, sizeof(dirname_buf), "%s" ROOTPREFIX "/lib/modules/%s",
 			 root, kversion);
 		dirname = dirname_buf;
 	}

tools/kmod-modprobe.c

@@ -125,8 +125,8 @@ static void help(const char *progname)
 		"\t-n, --dry-run               Do not execute operations, just print out\n"
 		"\t-n, --show                  Same as --dry-run\n"
 
-		"\t-C, --config=FILE           Use FILE instead of /etc/modprobe.d\n"
+		"\t-C, --config=FILE           Use FILE instead of " SYSCONFDIR "/modprobe.d\n"
-		"\t-d, --dirname=DIR           Use DIR as filesystem root for /lib/modules\n"
+		"\t-d, --dirname=DIR           Use DIR as filesystem root for " ROOTPREFIX "/lib/modules\n"
 		"\t-S, --set-version=VERSION   Use VERSION instead of `uname -r`\n"
 
 		"\t-s, --syslog                print to syslog, not stderr\n"
@@ -1252,7 +1252,7 @@ int main(int argc, char **orig_argv)
 			}
 			kversion = u.release;
 		}
-		snprintf(dirname_buf, sizeof(dirname_buf), "%s/lib/modules/%s",
+		snprintf(dirname_buf, sizeof(dirname_buf), "%s" ROOTPREFIX "/lib/modules/%s",
 			 root, kversion);
 		dirname = dirname_buf;
 	}