cleanup: tiny speedup of lib_dir checking

Instead of repeated lookup of global/library_dir - remember first
search in command context - saves couple lines in debug output...

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.105 -
 =====================================
+  Cache global library dir in command context.
   Return success when inserting dirs and links into device cache.
   Test for remote exclusive activation after activation fails.
   Support lvconvert --merge for thin snapshots.

lib/commands/toolcontext.c

@@ -1654,6 +1654,8 @@ int refresh_toolcontext(struct cmd_context *cmd)
 
 	cmd->hosttags = 0;
 
+	cmd->lib_dir = NULL;
+
 	if (!_init_lvm_conf(cmd))
 		return 0;
 

lib/commands/toolcontext.h

@@ -121,6 +121,7 @@ struct cmd_context {
 	struct dm_list tags;
 	int hosttags;
 
+	const char *lib_dir;		/* Cache value global/library_dir */
 	char system_dir[PATH_MAX];
 	char dev_dir[PATH_MAX];
 	char proc_dir[PATH_MAX];

lib/misc/sharedlib.c

@@ -16,6 +16,7 @@
 #include "lib.h"
 #include "config.h"
 #include "sharedlib.h"
+#include "toolcontext.h"
 
 #include <limits.h>
 #include <sys/stat.h>
@@ -25,13 +26,13 @@ void get_shared_library_path(struct cmd_context *cmd, const char *libname,
 			     char *path, size_t path_len)
 {
 	struct stat info;
-	const char *lib_dir;
 
 	/* If libname doesn't begin with '/' then use lib_dir/libname,
 	 * if present */
 	if (libname[0] == '/' ||
-	    !(lib_dir = find_config_tree_str(cmd, global_library_dir_CFG, NULL)) ||
-	    (dm_snprintf(path, path_len, "%s/%s", lib_dir,
+            (!cmd->lib_dir &&
+	     !(cmd->lib_dir = find_config_tree_str(cmd, global_library_dir_CFG, NULL))) ||
+	    (dm_snprintf(path, path_len, "%s/%s", cmd->lib_dir,
 			 libname) == -1) || stat(path, &info) == -1) {
 		strncpy(path, libname, path_len - 1);
 		path[path_len - 1] = '\0';