[GitHub] [incubator-nuttx] pkarashchenko commented on a diff in pull request #6083: sched/environ: Refine the environment variables storage layout

[GitBox <gi...@apache.org>]

pkarashchenko commented on code in PR #6083:
URL: https://github.com/apache/incubator-nuttx/pull/6083#discussion_r851652926


##########
sched/environ/env_dup.c:
##########
@@ -64,8 +64,8 @@
 int env_dup(FAR struct task_group_s *group)
 {
   FAR struct tcb_s *ptcb = this_task();
-  FAR char *envp = NULL;
-  size_t envlen;
+  FAR char **envp = NULL;
+  size_t envlen = 0;

Review Comment:
   probably renaming `envlen` -> `envc` can be a good option.



##########
sched/environ/env_dup.c:
##########
@@ -94,28 +96,50 @@ int env_dup(FAR struct task_group_s *group)
         {
           /* There is an environment, duplicate it */
 
-          envp = (FAR char *)group_malloc(group, envlen + 1);
+          envp = group_malloc(group, sizeof(*envp) * (envlen + 1));
           if (envp == NULL)
             {
               /* The parent's environment can not be inherited due to a
                * failure in the allocation of the child environment.
                */
 
-              envlen = 0;
-              ret    = -ENOMEM;
+              ret = -ENOMEM;
             }
           else
             {
               /* Duplicate the parent environment. */
 
-              memcpy(envp, ptcb->group->tg_envp, envlen + 1);
+              do
+                {
+                  if (ptcb->group->tg_envp[envlen] == NULL)
+                    {
+                      envp[envlen] = NULL;
+                      continue;

Review Comment:
   optional: below code can be moved to `else` and `continue` can be eliminated. Or even this may be moved out of `do {} while` like:
   ```
   /* Duplicate the parent environment. */
   
   envp[envlen--] = NULL;
   
   for (; envlen > 0; envlen--)
     {
   /* perform allocation here */
     }
   ```



##########
sched/environ/env_dup.c:
##########
@@ -94,28 +96,50 @@ int env_dup(FAR struct task_group_s *group)
         {
           /* There is an environment, duplicate it */
 
-          envp = (FAR char *)group_malloc(group, envlen + 1);
+          envp = group_malloc(group, sizeof(*envp) * (envlen + 1));
           if (envp == NULL)
             {
               /* The parent's environment can not be inherited due to a
                * failure in the allocation of the child environment.
                */
 
-              envlen = 0;
-              ret    = -ENOMEM;
+              ret = -ENOMEM;
             }
           else
             {
               /* Duplicate the parent environment. */
 
-              memcpy(envp, ptcb->group->tg_envp, envlen + 1);
+              do
+                {
+                  if (ptcb->group->tg_envp[envlen] == NULL)
+                    {
+                      envp[envlen] = NULL;
+                      continue;
+                    }
+
+                  envp[envlen] = group_malloc(group,
+                                  strlen(ptcb->group->tg_envp[envlen]) + 1);
+                  if (envp[envlen] == NULL)
+                    {
+                      while (envp[++envlen] != NULL)
+                        {
+                          group_free(group, envp[envlen]);
+                        }
+
+                      group_free(group, envp);
+                      ret = -ENOMEM;
+                      break;
+                    }
+
+                  strcpy(envp[envlen], ptcb->group->tg_envp[envlen]);
+                }
+              while (envlen--);

Review Comment:
   optional `> 0`



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