[PATCH 1/4] libkmod: add MODULE_DIR to override kernel modules directory

[Nikolay Amiantov <ab@fmap.me>]

From: Shea Levy <shea@shealevy.com>

It is used as a path if this environment variable is set, and `uname -r` is
appended to the end. Otherwise, default /lib/modules/`uname -r` is used as
usual.
---
 libkmod/libkmod.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/libkmod/libkmod.c b/libkmod/libkmod.c
index 69fe431..7b0247f 100644
--- a/libkmod/libkmod.c
+++ b/libkmod/libkmod.c
@@ -211,7 +211,7 @@ static const char *dirname_default_prefix = "/lib/modules";
 static char *get_kernel_release(const char *dirname)
 {
 	struct utsname u;
-	char *p;
+	char *p, *dirname_prefix;
 
 	if (dirname != NULL)
 		return path_make_absolute_cwd(dirname);
@@ -219,7 +219,10 @@ static char *get_kernel_release(const char *dirname)
 	if (uname(&u) < 0)
 		return NULL;
 
-	if (asprintf(&p, "%s/%s", dirname_default_prefix, u.release) < 0)
+	if ((dirname_prefix = getenv("MODULE_DIR")) == NULL)
+		dirname_prefix = dirname_default_prefix;
+
+	if (asprintf(&p, "%s/%s", dirname_prefix, u.release) < 0)
 		return NULL;
 
 	return p;
-- 
2.9.2