bindings: cxx: do not initialize a chip's shared_ptr with nullptr

A shared_ptr initialized with nullptr will still call the deleter which
causes a NULL-pointer dereference if we create a chip_iter when there
are no GPIO chips in the system.

Only initialize the current chip object in chip_iter if
gpiod_chip_iter_next_noclose() returned a valid pointer.

Signed-off-by: Patrick Boettcher <p@yai.se>
[Bartosz:
  - tweaked the commit message
  - use std::move when assigning the chip object]
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

diff --git a/bindings/cxx/iter.cpp b/bindings/cxx/iter.cpp
index 0f1105760f5b060782a14a1e97e7dfce2c0e220e..39e738d7ed997dad6e6ea72b9a527e4e60329f06 100644 (file)
--- a/bindings/cxx/iter.cpp
+++ b/bindings/cxx/iter.cpp
@@ -58,10 +58,12 @@ bool chip_iter::operator!=(const chip_iter& rhs) const noexcept
 }
 
 chip_iter::chip_iter(::gpiod_chip_iter *iter)
-       : _m_iter(iter, chip_iter_deleter),
-         _m_current(chip(::gpiod_chip_iter_next_noclose(this->_m_iter.get())))
+       : _m_iter(iter, chip_iter_deleter)
 {
+       ::gpiod_chip* first = ::gpiod_chip_iter_next_noclose(this->_m_iter.get());
 
+       if (first != nullptr)
+               this->_m_current = ::std::move(chip(first));
 }
 
 chip_iter& chip_iter::operator++(void)