int unsetenv(FAR const char *name)
{
FAR struct tcb_s *rtcb = (FAR struct tcb_s *)g_readytorun.head;
FAR struct task_group_s *group = rtcb->group;
FAR char *pvar;
FAR char *newenvp;
int newsize;
int ret = OK;
DEBUGASSERT(name && group);
/* Check if the variable exists */
sched_lock();
if (group && (pvar = env_findvar(group, name)) != NULL)
{
/* It does! Remove the name=value pair from the environment. */
(void)env_removevar(group, pvar);
/* Reallocate the new environment buffer */
newsize = group->tg_envsize;
newenvp = (FAR char *)kumm_realloc(group->tg_envp, newsize);
if (!newenvp)
{
set_errno(ENOMEM);
ret = ERROR;
}
else
{
/* Save the new environment pointer (it might have changed due to
* reallocation.
*/
group->tg_envp = newenvp;
}
}
sched_unlock();
return ret;
}
int munmap(FAR void *start, size_t length)
{
FAR struct fs_rammap_s *prev;
FAR struct fs_rammap_s *curr;
FAR void *newaddr;
unsigned int offset;
int ret;
int err;
/* Find a region containing this start and length in the list of regions */
rammap_initialize();
ret = sem_wait(&g_rammaps.exclsem);
if (ret < 0)
{
return ERROR;
}
/* Seach the list of regions */
for (prev = NULL, curr = g_rammaps.head; curr; prev = curr, curr = curr->flink)
{
/* Does this region include any part of the specified range? */
if ((uintptr_t)start < (uintptr_t)curr->addr + curr->length &&
(uintptr_t)start + length >= (uintptr_t)curr->addr)
{
break;
}
}
/* Did we find the region */
if (!curr)
{
fdbg("Region not found\n");
err = EINVAL;
goto errout_with_semaphore;
}
/* Get the offset from the beginning of the region and the actual number
* of bytes to "unmap". All mappings must extend to the end of the region.
* There is no support for free a block of memory but leaving a block of
* memory at the end. This is a consequence of using kumm_realloc() to
* simulate the unmapping.
*/
offset = start - curr->addr;
if (offset + length < curr->length)
{
fdbg("Cannot umap without unmapping to the end\n");
err = ENOSYS;
goto errout_with_semaphore;
}
/* Okay.. the region is beging umapped to the end. Make sure the length
* indicates that.
*/
length = curr->length - offset;
/* Are we unmapping the entire region (offset == 0)? */
if (length >= curr->length)
{
/* Yes.. remove the mapping from the list */
if (prev)
{
prev->flink = curr->flink;
}
else
{
g_rammaps.head = curr->flink;
}
/* Then free the region */
kumm_free(curr);
}
/* No.. We have been asked to "unmap' only a portion of the memory
* (offset > 0).
*/
else
{
newaddr = kumm_realloc(curr->addr, sizeof(struct fs_rammap_s) + length);
DEBUGASSERT(newaddr == (FAR void*)(curr->addr));
curr->length = length;
}
sem_post(&g_rammaps.exclsem);
return OK;
errout_with_semaphore:
sem_post(&g_rammaps.exclsem);
set_errno(err);
return ERROR;
}
