On Sun, 01 May 2016 14:43:42 +0200, Alexander E. Patrakov wrote: > > Even if no files have been changed, the config may become outdated > due to hot-plugged devices. > > Note: this patch has a huge potential to crash badly-written applications > that keep config pointers and strings for too long. But I see no other > way to support hot-pluggable devices. Can we opt in this feature, e.g. by enabling it via some new API function? Enabling this blindly appears too risky. thanks, Takashi > Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=54029 > Signed-off-by: Alexander E. Patrakov <patrakov@xxxxxxxxx> > --- > src/conf.c | 63 ++++++++++++++++++++++++---------------------------------- > src/confmisc.c | 4 +++- > 2 files changed, 29 insertions(+), 38 deletions(-) > > diff --git a/src/conf.c b/src/conf.c > index f8b7a66..34576aa 100644 > --- a/src/conf.c > +++ b/src/conf.c > @@ -3661,14 +3661,15 @@ SND_DLSYM_BUILD_VERSION(snd_config_hook_load_for_all_cards, SND_CONFIG_DLSYM_VER > #endif > > /** > - * \brief Updates a configuration tree by rereading the configuration files (if needed). > + * \brief Updates a configuration tree by rereading the configuration files. > * \param[in,out] _top Address of the handle to the top-level node. > * \param[in,out] _update Address of a pointer to private update information. > * \param[in] cfgs A list of configuration file names, delimited with ':'. > * If \p cfgs is \c NULL, the default global > * configuration file is used. > - * \return 0 if \a _top was up to date, 1 if the configuration files > - * have been reread, otherwise a negative error code. > + * \return 0 if \a _top was up to date (this can happen only in previous > + * ALSA-lib versions), 1 if the configuration files have been > + * reread successfully, otherwise a negative error code. > * > * The variables pointed to by \a _top and \a _update can be initialized > * to \c NULL before the first call to this function. The private > @@ -3679,7 +3680,8 @@ SND_DLSYM_BUILD_VERSION(snd_config_hook_load_for_all_cards, SND_CONFIG_DLSYM_VER > * The global configuration files are specified in the environment variable > * \c ALSA_CONFIG_PATH. > * > - * \warning If the configuration tree is reread, all string pointers and > + * \warning In order to deal with hot-pluggable devices, the configuration > + * tree is always reread, even if nothing changed. All string pointers and > * configuration node handles previously obtained from this tree become > * invalid. > * > @@ -3754,35 +3756,6 @@ int snd_config_update_r(snd_config_t **_top, snd_config_update_t **_update, cons > local->count--; > } > } > - if (!update) > - goto _reread; > - if (local->count != update->count) > - goto _reread; > - for (k = 0; k < local->count; ++k) { > - struct finfo *lf = &local->finfo[k]; > - struct finfo *uf = &update->finfo[k]; > - if (strcmp(lf->name, uf->name) != 0 || > - lf->dev != uf->dev || > - lf->ino != uf->ino || > - lf->mtime != uf->mtime) > - goto _reread; > - } > - err = 0; > - > - _end: > - if (err < 0) { > - if (top) { > - snd_config_delete(top); > - *_top = NULL; > - } > - if (update) { > - snd_config_update_free(update); > - *_update = NULL; > - } > - } > - if (local) > - snd_config_update_free(local); > - return err; > > _reread: > *_top = NULL; > @@ -3823,15 +3796,31 @@ int snd_config_update_r(snd_config_t **_top, snd_config_update_t **_update, cons > *_top = top; > *_update = local; > return 1; > + > +_end: > + if (err < 0) { > + if (top) { > + snd_config_delete(top); > + *_top = NULL; > + } > + if (update) { > + snd_config_update_free(update); > + *_update = NULL; > + } > + } > + if (local) > + snd_config_update_free(local); > + return err; > } > > /** > - * \brief Updates #snd_config by rereading the global configuration files (if needed). > - * \return 0 if #snd_config was up to date, 1 if #snd_config was > - * updated, otherwise a negative error code. > + * \brief Updates #snd_config by rereading the global configuration files. > + * \return 0 if #snd_config was up to date (this can happen only in previous > + * ALSA-lib versions), 1 if #snd_config was updated successfully, > + * otherwise a negative error code. > * > * \warning Whenever #snd_config is updated, all string pointers and > - * configuration node handles previously obtained from it may become > + * configuration node handles previously obtained from it become > * invalid. > * > * \par Errors: > diff --git a/src/confmisc.c b/src/confmisc.c > index ae0275f..8f97b72 100644 > --- a/src/confmisc.c > +++ b/src/confmisc.c > @@ -599,7 +599,9 @@ static int open_ctl(long card, snd_ctl_t **ctl) > char name[16]; > snprintf(name, sizeof(name), "hw:%li", card); > name[sizeof(name)-1] = '\0'; > - return snd_ctl_open(ctl, name, 0); > + > + /* Take care not to update the config - we may be running hooks on pcms right now */ > + return snd_ctl_open_lconf(ctl, name, 0, snd_config); > } > > #if 0 > -- > 2.8.0 > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
