Implement Filelock

fs/vfs/fs_lock.c

@@ -99,13 +99,6 @@ static int file_lock_normalize(FAR struct file *filep,
  off_t start;
  off_t end;
 
- /* Check the legality of incoming flocks */
-
- if (flock->l_len - 1 > OFFSET_MAX - flock->l_start)
- {
- return -EOVERFLOW;
- }
-
  /* Check that the type brought in the flock is correct */
 
  switch (flock->l_type)
@@ -161,8 +154,18 @@ static int file_lock_normalize(FAR struct file *filep,
  }
 
  start += flock->l_start;
+ if (start < 0)
+ {
+ return -EINVAL;
+ }
+
  if (flock->l_len > 0)
  {
+ if (flock->l_len - 1 > OFFSET_MAX - start)
+ {
+ return -EOVERFLOW;
+ }
+
  end = start + flock->l_len - 1;
  }
  else if (flock->l_len < 0)
@@ -181,7 +184,6 @@ static int file_lock_normalize(FAR struct file *filep,
  }
 
  out->l_whence = SEEK_SET;
- out->l_pid = getpid();
  out->l_type = flock->l_type;
  out->l_start = start;
  out->l_end = end;
@@ -546,8 +548,6 @@ int file_getlk(FAR struct file *filep, FAR struct flock *flock)
  return ret;
  }
 
- flock->l_type = F_UNLCK;
-
  nxmutex_lock(&g_protect_lock);
 
  bucket = file_lock_find_bucket(path);
@@ -559,19 +559,21 @@ int file_getlk(FAR struct file *filep, FAR struct flock *flock)
  if (file_lock_is_conflict(flock, &file_lock->fl_lock))
  {
  memcpy(flock, &file_lock->fl_lock, sizeof(*flock));
- break;
+ goto out;
  }
  }
  }
 
- nxmutex_unlock(&g_protect_lock);
+ flock->l_type = F_UNLCK;
 
  /* Convert back to flock
  * The flock information saved in filelock is used as an offset
  * to the relative position. And for upper level applications,
  * l_len should be converted to cover the data quantity
  */
 
+out:
+ nxmutex_unlock(&g_protect_lock);
  if (flock->l_end == OFFSET_MAX)
  {
  flock->l_len = 0;
@@ -625,6 +627,8 @@ int file_setlk(FAR struct file *filep, FAR struct flock *flock,
  return ret;
  }
 
+ request.l_pid = getpid();
+
  nxmutex_lock(&g_protect_lock);
 
  bucket = file_lock_find_bucket(path);