glusterd: fix gcc7 warnings

    [sh]$ gcc --version
    gcc (GCC) 7.3.1 20180303 (Red Hat 7.3.1-5)

Warnings were of the type below:

xlators/mgmt/glusterd/src/glusterd-store.c:3285:33:
warning: ‘/options’ directive output may be truncated writing 8 bytes into a region of size between 1 and 4096 [-Wformat-truncation=]
         snprintf (path, len, "%s/options", conf->workdir);
                                 ^~~~~~~~
xlators/mgmt/glusterd/src/glusterd-store.c:1280:39:
warning: ‘/snaps/’ directive output may be truncated writing 7 bytes into a region of size between 1 and 4096 [-Wformat-truncation=]
         snprintf (snap_fpath, len, "%s/snaps/%s/%s", priv->workdir,
                                       ^~~~~~~

* Also changed some places where there was issues with key size
* Made sure all the 'char buf[SOMESIZE] = {0,};' are changed to 'char buf[SOMESIZE] = "";`
  - In the files I changed

* Also edited coding standard to reflect that.

updates: bz#1193929
Change-Id: I04c652624ac63199cea2077e46b3a5def37c3689
Signed-off-by: Amar Tumballi <amarts@redhat.com>

3 files changed, 54 insertions, 22 deletions

diff --git a/doc/developer-guide/coding-standard.md b/doc/developer-guide/coding-standard.md
index eb9cd9ddc39..9bc15a5cc15 100644
--- a/doc/developer-guide/coding-standard.md
+++ b/doc/developer-guide/coding-standard.md
@@ -156,6 +156,28 @@ instead.
 gf_boolean_t port_inuse[65536]; /* 256KB, this actually happened */
 ```
 
+NOTE: Ideal is to limit the stack array to less than 256 bytes.
+
+
+Character array initializing
+----------------------------
+
+It is recommended to keep the character array initializing to empty string.
+
+*Good:*
+```
+char msg[1024] = "";
+```
+
+Not so much recommended, even though it means the same.
+
+```
+char msg[1024] = {0,};
+```
+
+We recommend above to structure initialization.
+
+
 
 Validate all arguments to a function
 ------------------------------------
diff --git a/xlators/mgmt/glusterd/src/glusterd-brick-ops.c b/xlators/mgmt/glusterd/src/glusterd-brick-ops.c
index c3ec249e6ba..eb85b3c263a 100644
--- a/xlators/mgmt/glusterd/src/glusterd-brick-ops.c
+++ b/xlators/mgmt/glusterd/src/glusterd-brick-ops.c
@@ -416,7 +416,7 @@ __glusterd_handle_add_brick (rpcsvc_request_t *req)
         char                            *volname = NULL;
         int                             brick_count = 0;
         void                            *cli_rsp = NULL;
-        char                            err_str[2048] = {0,};
+        char                            err_str[2048] = "";
         gf_cli_rsp                      rsp = {0,};
         glusterd_volinfo_t              *volinfo = NULL;
         xlator_t                        *this = NULL;
@@ -777,8 +777,8 @@ subvol_matcher_destroy (int *subvols)
 int
 glusterd_set_detach_bricks(dict_t *dict, glusterd_volinfo_t *volinfo)
 {
-        char key[256] = {0,};
-        char value[256] = {0,};
+        char key[64] = "";
+        char value[2048] = ""; /* hostname + path */
         int brick_num = 0;
         int hot_brick_num = 0;
         glusterd_brickinfo_t *brickinfo;
@@ -885,16 +885,16 @@ __glusterd_handle_remove_brick (rpcsvc_request_t *req)
         dict_t                   *dict             = NULL;
         int32_t                   count            = 0;
         char                     *brick            = NULL;
-        char                      key[256]         = {0,};
+        char                      key[64]          = "";
         int                       i                = 1;
         glusterd_volinfo_t       *volinfo          = NULL;
         glusterd_brickinfo_t     *brickinfo        = NULL;
         glusterd_brickinfo_t     **brickinfo_list  = NULL;
         int                      *subvols          = NULL;
-        char                      err_str[2048]    = {0};
+        char                      err_str[2048]    = "";
         gf_cli_rsp                rsp              = {0,};
         void                     *cli_rsp          = NULL;
-        char                      vol_type[256]    = {0,};
+        char                      vol_type[256]    = "";
         int32_t                   replica_count    = 0;
         char                     *volname          = 0;
         xlator_t                 *this             = NULL;
@@ -1319,10 +1319,9 @@ glusterd_op_perform_add_bricks (glusterd_volinfo_t *volinfo, int32_t count,
         glusterd_brickinfo_t         *brickinfo      = NULL;
         glusterd_gsync_status_temp_t  param          = {0, };
         gf_boolean_t                  restart_needed = 0;
-        char                          msg[1024] __attribute__((unused)) = {0, };
         int                           caps           = 0;
         int                           brickid        = 0;
-        char                          key[PATH_MAX]  = "";
+        char                          key[64]  = "";
         char                         *brick_mount_dir  = NULL;
         xlator_t                     *this           = NULL;
         glusterd_conf_t              *conf           = NULL;
@@ -1521,6 +1520,7 @@ glusterd_op_perform_add_bricks (glusterd_volinfo_t *volinfo, int32_t count,
                 if (ret)
                         goto out;
 #ifdef HAVE_BD_XLATOR
+                char msg[1024] = "";
                 /* Check for VG/thin pool if its BD volume */
                 if (brickinfo->vg[0]) {
                         ret = glusterd_is_valid_vg (brickinfo, 0, msg);
@@ -1674,8 +1674,8 @@ glusterd_op_stage_add_brick (dict_t *dict, char **op_errstr, dict_t *rsp_dict)
         glusterd_brickinfo_t                    *brickinfo = NULL;
         glusterd_volinfo_t                      *volinfo = NULL;
         xlator_t                                *this = NULL;
-        char                                    msg[2048] = {0,};
-        char                                    key[PATH_MAX] = "";
+        char                                    msg[4096] = "";
+        char                                    key[64] = "";
         gf_boolean_t                            brick_alloc = _gf_false;
         char                                    *all_bricks = NULL;
         char                                    *str_ret = NULL;
@@ -1997,8 +1997,8 @@ glusterd_remove_brick_validate_bricks (gf1_op_commands cmd, int32_t brick_count,
                                        gf_cli_defrag_type cmd_defrag)
 {
         char                   *brick       = NULL;
-        char                    msg[2048]   = {0,};
-        char                    key[256]    = {0,};
+        char                    msg[2048]   = "";
+        char                    key[64]     = "";
         glusterd_brickinfo_t   *brickinfo   = NULL;
         glusterd_peerinfo_t    *peerinfo    = NULL;
         int                     i           = 0;
@@ -2140,7 +2140,7 @@ glusterd_op_stage_remove_brick (dict_t *dict, char **op_errstr)
         glusterd_volinfo_t     *volinfo     = NULL;
         char                   *errstr      = NULL;
         int32_t                 brick_count = 0;
-        char                    msg[2048]   = {0,};
+        char                    msg[2048]   = "";
         int32_t                 flag        = 0;
         gf1_op_commands         cmd         = GF_OP_CMD_NONE;
         char                   *task_id_str = NULL;
@@ -2719,9 +2719,9 @@ glusterd_op_remove_brick (dict_t *dict, char **op_errstr)
         char                    *brick         = NULL;
         int32_t                 count          = 0;
         int32_t                 i              = 1;
-        char                    key[256]       = {0,};
+        char                    key[64]        = "";
         int32_t                 flag           = 0;
-        char                    err_str[4096]  = {0,};
+        char                    err_str[4096]  = "";
         int                     need_rebalance = 0;
         int                     force          = 0;
         gf1_op_commands         cmd            = 0;
@@ -3243,7 +3243,7 @@ __glusterd_handle_add_tier_brick (rpcsvc_request_t *req)
         char                            *volname = NULL;
         int                             brick_count = 0;
         void                            *cli_rsp = NULL;
-        char                            err_str[2048] = {0,};
+        char                            err_str[2048] = "";
         gf_cli_rsp                      rsp = {0,};
         glusterd_volinfo_t              *volinfo = NULL;
         xlator_t                        *this = NULL;
diff --git a/xlators/mgmt/glusterd/src/glusterd.h b/xlators/mgmt/glusterd/src/glusterd.h
index c2a69c79419..49a1dc6dc08 100644
--- a/xlators/mgmt/glusterd/src/glusterd.h
+++ b/xlators/mgmt/glusterd/src/glusterd.h
@@ -141,6 +141,16 @@ struct glusterd_volgen {
         dict_t *dict;
 };
 
+/* Keeping all the paths required in glusterd would
+   cause many buffer overflow errors, as we append
+   more defined paths to the brick path, workdir etc etc.
+   It is better to keep limit on this as lesser value,
+   so we get an option to continue with all functionalities.
+   For example, snapname max would be appended on brick-path and
+   would be stored on workdir... all of these being PATH_MAX, is
+   not an ideal situation for success. */
+#define VALID_GLUSTERD_PATHMAX (PATH_MAX - (256 + 64))
+
 typedef struct {
         struct _volfile_ctx     *volfile;
         pthread_mutex_t          mutex;
@@ -148,8 +158,8 @@ typedef struct {
         gf_boolean_t             verify_volfile_checksum;
         gf_boolean_t             trace;
         uuid_t                   uuid;
-        char                     workdir[PATH_MAX];
-        char                     rundir[PATH_MAX];
+        char                     workdir[VALID_GLUSTERD_PATHMAX];
+        char                     rundir[VALID_GLUSTERD_PATHMAX];
         rpcsvc_t                *rpc;
         glusterd_svc_t           shd_svc;
         glusterd_svc_t           nfs_svc;
@@ -212,10 +222,10 @@ typedef enum gf_brick_status {
 
 struct glusterd_brickinfo {
         char               hostname[1024];
-        char               path[PATH_MAX];
-        char               real_path[PATH_MAX];
-        char               device_path[PATH_MAX];
-        char               mount_dir[PATH_MAX];
+        char               path[VALID_GLUSTERD_PATHMAX];
+        char               real_path[VALID_GLUSTERD_PATHMAX];
+        char               device_path[VALID_GLUSTERD_PATHMAX];
+        char               mount_dir[VALID_GLUSTERD_PATHMAX];
         char               brick_id[1024];/*Client xlator name, AFR changelog name*/
         char               fstype [NAME_MAX]; /* Brick file-system type */
         char               mnt_opts [1024]; /* Brick mount options */