[PATCH iproute2-next] ip: add IP_LIB_DIR environment variable

[Sergey Ryazanov <ryazanov.s.a@gmail.com>]

Do not hardcode /usr/lib/ip as a path and allow libraries path
configuration in run-time.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
---
 ip/ip.c        | 15 +++++++++++++++
 ip/ip_common.h |  2 ++
 ip/iplink.c    |  5 +----
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/ip/ip.c b/ip/ip.c
index 5e31957f..38600e51 100644
--- a/ip/ip.c
+++ b/ip/ip.c
@@ -25,6 +25,10 @@
 #include "color.h"
 #include "rt_names.h"
 
+#ifndef LIBDIR
+#define LIBDIR "/usr/lib"
+#endif
+
 int preferred_family = AF_UNSPEC;
 int human_readable;
 int use_iec;
@@ -41,6 +45,17 @@ bool do_all;
 
 struct rtnl_handle rth = { .fd = -1 };
 
+const char *get_ip_lib_dir(void)
+{
+	const char *lib_dir;
+
+	lib_dir = getenv("IP_LIB_DIR");
+	if (!lib_dir)
+		lib_dir = LIBDIR "/ip";
+
+	return lib_dir;
+}
+
 static void usage(void) __attribute__((noreturn));
 
 static void usage(void)
diff --git a/ip/ip_common.h b/ip/ip_common.h
index d604f755..227eddd3 100644
--- a/ip/ip_common.h
+++ b/ip/ip_common.h
@@ -27,6 +27,8 @@ struct link_filter {
 	int target_nsid;
 };
 
+const char *get_ip_lib_dir(void);
+
 int get_operstate(const char *name);
 int print_linkinfo(struct nlmsghdr *n, void *arg);
 int print_addrinfo(struct nlmsghdr *n, void *arg);
diff --git a/ip/iplink.c b/ip/iplink.c
index d6b766de..4250b2c3 100644
--- a/ip/iplink.c
+++ b/ip/iplink.c
@@ -34,9 +34,6 @@
 #include "namespace.h"
 
 #define IPLINK_IOCTL_COMPAT	1
-#ifndef LIBDIR
-#define LIBDIR "/usr/lib"
-#endif
 
 #ifndef GSO_MAX_SIZE
 #define GSO_MAX_SIZE		65536
@@ -157,7 +154,7 @@ struct link_util *get_link_kind(const char *id)
 		if (strcmp(l->id, id) == 0)
 			return l;
 
-	snprintf(buf, sizeof(buf), LIBDIR "/ip/link_%s.so", id);
+	snprintf(buf, sizeof(buf), "%s/link_%s.so", get_ip_lib_dir(), id);
 	dlh = dlopen(buf, RTLD_LAZY);
 	if (dlh == NULL) {
 		/* look in current binary, only open once */
-- 
2.26.2