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From:   Doug Nazar <nazard@nazar.ca>
To:     linux-nfs@vger.kernel.org
Subject: [PATCH 4/4] nfsidmap: Allow overriding location of method libraries
Date:   Wed, 22 Jul 2020 01:53:54 -0400
Message-Id: <20200722055354.28132-5-nazard@nazar.ca>
In-Reply-To: <20200722055354.28132-1-nazard@nazar.ca>
References: <20200722055354.28132-1-nazard@nazar.ca>
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Signed-off-by: Doug Nazar <nazard@nazar.ca>
---
 support/nfsidmap/libnfsidmap.c | 40 ++++++++++++++++++++++++----------
 1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/support/nfsidmap/libnfsidmap.c b/support/nfsidmap/libnfsidmap.c
index 6b5647d2..22b319b8 100644
--- a/support/nfsidmap/libnfsidmap.c
+++ b/support/nfsidmap/libnfsidmap.c
@@ -237,24 +237,40 @@ static int load_translation_plugin(char *method, struct mapping_plugin *plgn)
 {
 	void *dl = NULL;
 	struct trans_func *trans = NULL;
-	libnfsidmap_plugin_init_t init_func;
+	libnfsidmap_plugin_init_t init_func = NULL;
 	char plgname[128];
 	int ret = 0;
 
-	snprintf(plgname, sizeof(plgname), "%s/%s.so", PATH_PLUGINS, method);
+	/* Look for library using search path first to allow overriding */
+	snprintf(plgname, sizeof(plgname), "%s.so", method);
 
 	dl = dlopen(plgname, RTLD_NOW | RTLD_LOCAL);
-	if (dl == NULL) {
-		IDMAP_LOG(1, ("libnfsidmap: Unable to load plugin: %s",
-			  dlerror()));
-		return -1;
+	if (dl != NULL) {
+		/* Is it really one of our libraries */
+		init_func = (libnfsidmap_plugin_init_t) dlsym(dl, PLUGIN_INIT_FUNC);
+		if (init_func == NULL) {
+			dlclose(dl);
+			dl = NULL;
+		}
 	}
-	init_func = (libnfsidmap_plugin_init_t) dlsym(dl, PLUGIN_INIT_FUNC);
-	if (init_func == NULL) {
-		IDMAP_LOG(1, ("libnfsidmap: Unable to get init function: %s",
-			  dlerror()));
-		dlclose(dl);
-		return -1;
+
+	if (dl == NULL) {
+		/* Fallback to hard-coded path */
+		snprintf(plgname, sizeof(plgname), "%s/%s.so", PATH_PLUGINS, method);
+
+		dl = dlopen(plgname, RTLD_NOW | RTLD_LOCAL);
+		if (dl == NULL) {
+			IDMAP_LOG(1, ("libnfsidmap: Unable to load plugin: %s",
+				  dlerror()));
+			return -1;
+		}
+		init_func = (libnfsidmap_plugin_init_t) dlsym(dl, PLUGIN_INIT_FUNC);
+		if (init_func == NULL) {
+			IDMAP_LOG(1, ("libnfsidmap: Unable to get init function: %s",
+				  dlerror()));
+			dlclose(dl);
+			return -1;
+		}
 	}
 	trans = init_func();
 	if (trans == NULL) {
-- 
2.26.2