[glusterfs] Allow to set dynamic library path from env variable

Summary:
This allows to ship all glusterfs dependencies to hadoop
machines in a tarball.

Test Plan:
- build tarball: https://phabricator.fb.com/P2848521
- scp to a machine with no gluster installed

  echo "Hellow world" | LD_LIBRARY_PATH=glusterfs_libs GLUSTER_LIBDIR=glusterfs_libs ./glfscat $(shuf -n 1 <(smcc ls storage.gluster.gfsops.frc1) | cut -d: -f 1) groot /gfsetlprocstore/adslearner/users/azzolini/hello_world.txt

(code for glfscat follows in a separate diff)

Reviewers: rwareing

Reviewed By: rwareing

Differential Revision: https://phabricator.fb.com/D1009665

Change-Id: I8812929fc127ca291aa66e2430b5633892235915
Signed-off-by: Kevin Vigor <kvigor@fb.com>
Reviewed-on: http://review.gluster.org/16032
Reviewed-by: Shreyas Siravara <shreyas.siravara@gmail.com>
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>

1 files changed, 13 insertions, 3 deletions

diff --git a/libglusterfs/src/xlator.c b/libglusterfs/src/xlator.c
index 3c1cde50fa0..b2529d3c4f7 100644
--- a/libglusterfs/src/xlator.c
+++ b/libglusterfs/src/xlator.c
@@ -117,6 +117,14 @@ out:
 }
 
 
+static const char *xlator_lib_path (void)
+{
+        const char *libdir_env = getenv ("GLUSTER_LIBDIR");
+
+        return libdir_env ? libdir_env : XLATORDIR;
+}
+
+
 int
 xlator_volopt_dynload (char *xlator_type, void **dl_handle,
                        volume_opt_list_t *opt_list)
@@ -130,9 +138,11 @@ xlator_volopt_dynload (char *xlator_type, void **dl_handle,
         /* socket.so doesn't fall under the default xlator directory, hence we
          * need this check */
         if (!strstr(xlator_type, "rpc-transport"))
-                ret = gf_asprintf (&name, "%s/%s.so", XLATORDIR, xlator_type);
+                ret = gf_asprintf (&name, "%s/%s.so", xlator_lib_path (),
+                                   xlator_type);
         else
-                ret = gf_asprintf (&name, "%s/%s.so", XLATORPARENTDIR, xlator_type);
+                ret = gf_asprintf (&name, "%s/../%s.so", xlator_lib_path (),
+                                   xlator_type);
         if (-1 == ret) {
                 goto out;
         }
@@ -183,7 +193,7 @@ xlator_dynload (xlator_t *xl)
 
         INIT_LIST_HEAD (&xl->volume_options);
 
-        ret = gf_asprintf (&name, "%s/%s.so", XLATORDIR, xl->type);
+        ret = gf_asprintf (&name, "%s/%s.so", xlator_lib_path (), xl->type);
         if (-1 == ret) {
                 goto out;
         }