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, 6 insertions, 5 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-quota.c b/xlators/mgmt/glusterd/src/glusterd-quota.c
index 55699cc57a9..0d7113bc1a0 100644
--- a/xlators/mgmt/glusterd/src/glusterd-quota.c
+++ b/xlators/mgmt/glusterd/src/glusterd-quota.c
@@ -392,10 +392,11 @@ void
 glusterd_stop_all_quota_crawl_service (glusterd_conf_t *priv,
                                        glusterd_volinfo_t *volinfo, int type)
 {
-        char                       pid_dir[PATH_MAX]  = {0, };
-        char                       pidfile[PATH_MAX]  = {0,};
-        struct dirent             *entry              = NULL;
         DIR                       *dir                = NULL;
+        struct dirent             *entry              = NULL;
+        struct dirent              scratch[2]         = {{0,},};
+        char                       pid_dir[PATH_MAX]  = {0,};
+        char                       pidfile[PATH_MAX]  = {0,};
 
         GLUSTERD_GET_QUOTA_CRAWL_PIDDIR (pid_dir, volinfo, type);
 
@@ -403,7 +404,7 @@ glusterd_stop_all_quota_crawl_service (glusterd_conf_t *priv,
         if (dir == NULL)
                 return;
 
-        GF_FOR_EACH_ENTRY_IN_DIR (entry, dir);
+        GF_FOR_EACH_ENTRY_IN_DIR (entry, dir, scratch);
         while (entry) {
                 snprintf (pidfile, sizeof (pidfile), "%s/%s",
                           pid_dir, entry->d_name);
@@ -412,7 +413,7 @@ glusterd_stop_all_quota_crawl_service (glusterd_conf_t *priv,
                                               _gf_true);
                 sys_unlink (pidfile);
 
-                GF_FOR_EACH_ENTRY_IN_DIR (entry, dir);
+                GF_FOR_EACH_ENTRY_IN_DIR (entry, dir, scratch);
         }
         sys_closedir (dir);
 }