Poppler plugin gvloadimage_poppler_load: fix: match Glib allocation and free

The variable `absolute` is allocated using Glib’s `g_strdup` and friends.
Quoting the Glib docs:¹

  It's important to match `g_malloc()` (and wrappers such as `g_new()`) with
  `g_free()`, `g_slice_alloc()` (and wrappers such as `g_slice_new()`) with
  `g_slice_free()`, plain `malloc()` with `free()`, and (if you're using C++)
  `new` with `delete` and `new[]` with `delete[]`. Otherwise bad things can
  happen, since these allocators may use different memory pools (and new/delete
  call constructors and destructors).

So a custom allocation scheme or arena can be in play. Basically if you
`g_strdup` and then pair this with `free` (as was done in the code prior to this
commit), you risk leaking memory from the Glib pool and corrupting your system
allocator.

Having said that, this is no longer a concern in newer Glib:

  Since GLib 2.46 `g_malloc()` is hardcoded to always use the system malloc
  implementation.

Still, why tempt fate?

¹ https://developer-old.gnome.org/glib/stable/glib-Memory-Allocation.html

diff --git a/plugin/poppler/gvloadimage_poppler.c b/plugin/poppler/gvloadimage_poppler.c
index 8e85fdbb5b9971ec122bcf8456fb4c6d5d2e7acd..185c1d970333bb02111c50f8470ca9d7bdfa9b4a 100644 (file)
--- a/plugin/poppler/gvloadimage_poppler.c
+++ b/plugin/poppler/gvloadimage_poppler.c
@@ -69,7 +69,7 @@ static PopplerDocument* gvloadimage_poppler_load(GVJ_t * job, usershape_t *us)
 
                uri = g_filename_to_uri (absolute, NULL, &error);
 
-               free (absolute);
+               g_free(absolute);
                if (uri == NULL) {
                    printf("%s\n", error->message);
                    return NULL;