planck: sh hangs with long output

I noticed that, with the current HEAD a133e08, executing with sh a command which produces a long enough (>1k) output, it hangs.

E.g.: (sh “for i in 0 1 2 3 4 5 6 7 8 9; do for j in 0 1 2 3 4 5 6 7 8 9; do for k in 0 1 2 3 4 5 6 7 8 9 0 1 2 3; do echo -n 1; done; done; done”)

This is due to read_child_pipe() in planck-c/shell.c, as it seems that in such case the first read attempt to get 1023 chars, and if it succeeds, the following ones are trying to get 0 bytes.

Changing the function to the following seems to work better:

static char* read_child_pipe(int pipe) {
  const int BLOCK_SIZE = 1024;
  int block_count = 1;
  char* res = malloc(BLOCK_SIZE * block_count);
  int count = 0, total = 0, num_to_read = BLOCK_SIZE - 1;
  while ((count = read(pipe, res + total, num_to_read)) > 0) {
    total += count;
    if (count < num_to_read)
      num_to_read -= count;
    else {
      block_count += 1;
      res = realloc(res, BLOCK_SIZE * block_count);
      num_to_read = BLOCK_SIZE;
    }
  }
  res[total] = 0;
  return res;
}

Cheers, Lorenzo