core: use readdir(3) with glibc, and associated cleanup

Starting with glibc-2.23 (i.e. what's in Fedora 25), readdir_r(3)
is marked as deprecated. Specifically the function decl in <dirent.h>
has the deprecated attribute, and now warnings are thrown during the
compile on Fedora 25 builds.

The readdir(_r)(3) man page (on Fedora 25 at least) and World+Dog say
that glibc's readdir(3) is, and always has been, MT-SAFE as long as
only one thread is accessing the directory object returned by opendir().
World+Dog also says there is a potential buffer overflow in readdir_r().
World+Dog suggests that it is preferable to simply use readdir(). There's
an implication that eventually readdir_r(3) will be removed from glibc.
POSIX has, apparently deprecated it in the standard, or even removed it
entirely.

Over and above that, our source near the various uses of readdir(_r)(3)
has a few unsafe uses of strcpy()+strcat().

(AFAIK nobody has looked at the readdir(3) implemenation in *BSD to see
if the same is true on those platforms, and we can't be sure of MacOS
even though we know it's based on *BSD.)

Change-Id: I5481f18ba1eebe7ee177895eecc9a80a71b60568
BUG: 1356998
Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>
Reviewed-on: http://review.gluster.org/14838
Smoke: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Kotresh HR <khiremat@redhat.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>

1 files changed, 10 insertions, 9 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-hooks.c b/xlators/mgmt/glusterd/src/glusterd-hooks.c
index 45a5912a1eb..cb3d38d2358 100644
--- a/xlators/mgmt/glusterd/src/glusterd-hooks.c
+++ b/xlators/mgmt/glusterd/src/glusterd-hooks.c
@@ -323,15 +323,16 @@ glusterd_hooks_run_hooks (char *hooks_path, glusterd_op_t op, dict_t *op_ctx,
 {
         xlator_t        *this                   = NULL;
         glusterd_conf_t *priv                   = NULL;
-        runner_t        runner                  = {0, };
-        struct dirent   *entry                  = NULL;
+        runner_t         runner                 = {0,};
         DIR             *hookdir                = NULL;
+        struct dirent   *entry                  = NULL;
+        struct dirent    scratch[2]             = {{0,},};
         char            *volname                = NULL;
-        char            **lines                 = NULL;
-        int             N                       = 8; /*arbitrary*/
-        int             lineno                  = 0;
-        int             line_count              = 0;
-        int             ret                     = -1;
+        char           **lines                  = NULL;
+        int              N                      = 8; /*arbitrary*/
+        int              lineno                 = 0;
+        int              line_count             = 0;
+        int              ret                    = -1;
 
         this = THIS;
         priv = this->private;
@@ -362,7 +363,7 @@ glusterd_hooks_run_hooks (char *hooks_path, glusterd_op_t op, dict_t *op_ctx,
 
         ret = -1;
         line_count = 0;
-        GF_FOR_EACH_ENTRY_IN_DIR (entry, hookdir);
+        GF_FOR_EACH_ENTRY_IN_DIR (entry, hookdir, scratch);
         while (entry) {
                 if (line_count == N-1) {
                         N *= 2;
@@ -376,7 +377,7 @@ glusterd_hooks_run_hooks (char *hooks_path, glusterd_op_t op, dict_t *op_ctx,
                         line_count++;
                 }
 
-                GF_FOR_EACH_ENTRY_IN_DIR (entry, hookdir);
+                GF_FOR_EACH_ENTRY_IN_DIR (entry, hookdir, scratch);
         }
 
         lines[line_count] = NULL;