Most of open functions in alsa-lib have the call pattern:
snd_config_update();
return snd_xxx_open(x, snd_config, ...);
This means that the toplevel config gets updated, and passed to a
local open function. Although snd_config_update() itself has a
pthread mutex to be thread safe, the whole procedure above isn't
thread safe. Namely, the global snd_config tree may be deleted and
recreated at any time while the open function is being processed.
This may lead to a data corruption and crash of the program.
For avoiding the corruption, this patch introduces a refcount to
config tree object. A few new helper functions are introduced as
well:
- snd_config_update_ref() does update and take the refcount of the
toplevel tree. The obtained config tree has to be freed via
snd_config_unref() below.
- snd_config_ref() and snd_config_unref() manage the refcount of the
config object. The latter eventually deletes the object when all
references are gone.
Along with these additions, the caller of snd_config_update() and
snd_config global tree in alsa-lib are replaced with the new helpers.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The configure script blindly adds -D_GNU_SOURCE to all build settings,
even on non-GNU systems. This isn't too much of a big deal (even if
it uses the wrong variable -- CFLAGS instead of CPPFLAGS), except that
the alsa-lib source itself determines whether to use GNU features when
this is defined (such as versionsort). So when we build on non-glibc
systems, we get build failures like:
src/ucm/parser.c:1268:18: error: 'versionsort' undeclared (first use in this function)
#define SORTFUNC versionsort
^
src/ucm/parser.c:1272:54: note: in expansion of macro 'SORTFUNC'
err = scandir(filename, &namelist, filename_filter, SORTFUNC);
^
The correct way to add these flags is to use the autoconf helper
AC_USE_SYSTEM_EXTENSIONS. Unfortunately, that triggers some more
bugs in the alsa build. This macro adds defines to config.h and
not directly to CPPFLAGS, so it relies on files correctly including
config.h before anything else. A number of alsa files do not do
this leading to build failures. The fix there is to shuffle the
includes around so that the local ones come first.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Remove several memory leaks by not aborting prematurely from a
snd_xxx_close() function when some operation fails.
This can happen when a USB device was unplugged.
- changed snd_config_get_id function to follow semantic of other get functions
- added snd_config_test_id
- added runtime pointer type (not persistent)
- added snd_config_make_pointer, snd_config_set_pointer, snd_config_get_pointer
- added type/contents checking for callback functions
- changed 'void *private_data' to 'snd_config_t *private_data'
- renamed card_strtype functions to card_driver
Control:
- fixed passing parameters to snd_ctl_async
Async handlers:
- added public snd_async_handler_get_signo function
Documentation:
- moved all documentation to source files
