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, 18 insertions, 12 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-snapshot-utils.c b/xlators/mgmt/glusterd/src/glusterd-snapshot-utils.c
index 46c8bad1aa9..1765df3d0ef 100644
--- a/xlators/mgmt/glusterd/src/glusterd-snapshot-utils.c
+++ b/xlators/mgmt/glusterd/src/glusterd-snapshot-utils.c
@@ -3443,12 +3443,13 @@ out:
 int32_t
 glusterd_copy_folder (const char *source, const char *destination)
 {
-        DIR             *dir_ptr                =       NULL;
-        struct dirent   *direntp                =       NULL;
-        int32_t         ret                     =       -1;
-        char            src_path[PATH_MAX]      =       "";
-        char            dest_path[PATH_MAX]     =       "";
-        xlator_t        *this                   =       NULL;
+        int32_t         ret                 = -1;
+        xlator_t       *this                = NULL;
+        DIR            *dir_ptr             = NULL;
+        struct dirent  *entry               = NULL;
+        struct dirent   scratch[2]          = {{0,},};
+        char            src_path[PATH_MAX]  = {0,};
+        char            dest_path[PATH_MAX] = {0,};
 
         this = THIS;
         GF_ASSERT (this);
@@ -3463,17 +3464,22 @@ glusterd_copy_folder (const char *source, const char *destination)
                 goto out;
         }
 
-        while ((direntp = sys_readdir (dir_ptr)) != NULL) {
-                if (strcmp (direntp->d_name, ".") == 0 ||
-                    strcmp (direntp->d_name, "..") == 0)
+        for (;;) {
+                errno = 0;
+                entry = sys_readdir (dir_ptr, scratch);
+                if (!entry || errno != 0)
+                        break;
+
+                if (strcmp (entry->d_name, ".") == 0 ||
+                    strcmp (entry->d_name, "..") == 0)
                         continue;
                 ret = snprintf (src_path, sizeof (src_path), "%s/%s",
-                                source, direntp->d_name);
+                                source, entry->d_name);
                 if (ret < 0)
                         goto out;
 
                 ret = snprintf (dest_path, sizeof (dest_path), "%s/%s",
-                                destination, direntp->d_name);
+                                destination, entry->d_name);
                 if (ret < 0)
                         goto out;
 
@@ -3487,7 +3493,7 @@ glusterd_copy_folder (const char *source, const char *destination)
         }
 out:
         if (dir_ptr)
-                sys_closedir (dir_ptr);
+                (void) sys_closedir (dir_ptr);
 
         return ret;
 }