From 31f0ff358b360ee461d845c1b3b5e5d38fa27925 Mon Sep 17 00:00:00 2001
From: Jo-Philipp Wich <jow@openwrt.org>
Date: Tue, 24 Feb 2015 23:55:09 +0100
Subject: [PATCH 1/1] kmodloader: search kmods relative to LD_LIBRARY_PATH

When LD_LIBRARY_PATH is set, then scan for kmods in each directory pointed to
by it. This is mainly useful for early boot invocations of kmodloader, e.g.
during the extroot setup phase.

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>
---
 kmodloader.c | 91 +++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 73 insertions(+), 18 deletions(-)

diff --git a/kmodloader.c b/kmodloader.c
index 04d7c1d..4300baf 100644
--- a/kmodloader.c
+++ b/kmodloader.c
@@ -36,7 +36,7 @@
 #include <libubox/avl-cmp.h>
 #include <libubox/utils.h>
 
-#define DEF_MOD_PATH "/lib/modules/%s/"
+#define DEF_MOD_PATH "/modules/%s/"
 
 #define INFO(fmt, ...) do { \
 	syslog(LOG_INFO, fmt, ## __VA_ARGS__); \
@@ -71,7 +71,51 @@ struct module {
 };
 
 static struct avl_tree modules;
-static char *prefix = "";
+
+static char **module_folders = NULL;
+
+static int init_module_folders(void)
+{
+	int n = 0;
+	struct stat st;
+	struct utsname ver;
+	char *s, *e, *p, path[256], ldpath[256];
+
+	e = ldpath;
+	s = getenv("LD_LIBRARY_PATH");
+
+	if (s)
+		e += snprintf(ldpath, sizeof(ldpath), "%s:", s);
+
+	e += snprintf(e, sizeof(ldpath) - (e - ldpath), "/lib");
+
+	uname(&ver);
+
+	for (s = p = ldpath; p <= e; p++) {
+		if (*p != ':' && *p != '\0')
+			continue;
+
+		*p = 0;
+		snprintf(path, sizeof(path), "%s" DEF_MOD_PATH, s, ver.release);
+
+		if (!stat(path, &st) && S_ISDIR(st.st_mode)) {
+			module_folders = realloc(module_folders, sizeof(p) * (n + 2));
+
+			if (!module_folders)
+				return -1;
+
+			module_folders[n++] = strdup(path);
+		}
+
+		s = p + 1;
+	}
+
+	if (!module_folders)
+		return -1;
+
+	module_folders[n] = NULL;
+	return 0;
+}
 
 static struct module *find_module(const char *name)
 {
@@ -89,18 +133,18 @@ static void free_modules(void)
 
 static char* get_module_path(char *name)
 {
+	char **p;
 	static char path[256];
-	struct utsname ver;
 	struct stat s;
 
-	if (!stat(name, &s))
+	if (!stat(name, &s) && S_ISREG(s.st_mode))
 		return name;
 
-	uname(&ver);
-	snprintf(path, 256, "%s" DEF_MOD_PATH "%s.ko", prefix, ver.release, name);
-
-	if (!stat(path, &s))
-		return path;
+	for (p = module_folders; *p; p++) {
+		snprintf(path, sizeof(path), "%s%s.ko", *p, name);
+		if (!stat(path, &s) && S_ISREG(s.st_mode))
+			return path;
+	}
 
 	return NULL;
 }
@@ -296,7 +340,7 @@ static struct module* get_module_info(const char *module, const char *name)
 	return m;
 }
 
-static int scan_module_folder(void)
+static int scan_module_folder(const char *dir)
 {
 	int gl_flags = GLOB_NOESCAPE | GLOB_MARK;
 	struct utsname ver;
@@ -305,8 +349,8 @@ static int scan_module_folder(void)
 	int j;
 
 	uname(&ver);
-	path = alloca(sizeof(DEF_MOD_PATH "*.ko") + strlen(prefix) + strlen(ver.release) + 1);
-	sprintf(path, "%s" DEF_MOD_PATH "*.ko", prefix, ver.release);
+	path = alloca(strlen(dir) + sizeof("*.ko") + 1);
+	sprintf(path, "%s*.ko", dir);
 
 	if (glob(path, gl_flags, NULL, &gl) < 0)
 		return -1;
@@ -328,6 +372,20 @@ static int scan_module_folder(void)
 	return 0;
 }
 
+static int scan_module_folders(void)
+{
+	int rv = 0;
+	char **p;
+
+	if (init_module_folders())
+		return -1;
+
+	for (p = module_folders; *p; p++)
+		rv |= scan_module_folder(*p);
+
+	return rv;
+}
+
 static int print_modinfo(char *module)
 {
 	int fd = open(module, O_RDONLY);
@@ -617,7 +675,7 @@ static int main_modinfo(int argc, char **argv)
 	if (argc != 2)
 		return print_usage("modinfo");
 
-	if (scan_module_folder())
+	if (scan_module_folders())
 		return -1;
 
 	name = get_module_name(argv[1]);
@@ -649,7 +707,7 @@ static int main_modprobe(int argc, char **argv)
 	if (scan_loaded_modules())
 		return -1;
 
-	if (scan_module_folder())
+	if (scan_module_folders())
 		return -1;
 
 	name = get_module_name(argv[1]);
@@ -693,9 +751,6 @@ static int main_loader(int argc, char **argv)
 	if (argc > 1)
 		dir = argv[1];
 
-	if (argc > 2)
-		prefix = argv[2];
-
 	path = malloc(strlen(dir) + 2);
 	strcpy(path, dir);
 	strcat(path, "*");
@@ -703,7 +758,7 @@ static int main_loader(int argc, char **argv)
 	if (scan_loaded_modules())
 		return -1;
 
-	if (scan_module_folder())
+	if (scan_module_folders())
 		return -1;
 
 	syslog(0, "kmodloader: loading kernel modules from %s\n", path);
-- 
2.30.2