Attachment 123387 Details for Bug 54029 – Patch that fixes the bug

Patch that fixes the bug

0001-conf-don-t-check-if-config-files-are-up-to-date.patch (text/plain), 4.80 KB, created by Alexander E. Patrakov on 2016-05-01 12:48:51 UTC

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Creator: Alexander E. Patrakov

Created: 2016-05-01 12:48:51 UTC

Size: 4.80 KB

patch

obsolete

>From dec823ab95788e54a08c45e98c24673960d19860 Mon Sep 17 00:00:00 2001
>From: "Alexander E. Patrakov" <patrakov@gmail.com>
>Date: Sun, 1 May 2016 17:21:20 +0500
>Subject: [PATCH] conf: don't check if config files are up to date
>
>Even if no files have been changed, the config may become outdated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.
>
>Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=54029
>Signed-off-by: Alexander E. Patrakov <patrakov@gmail.com>
>---
> 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
>

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Attachments on bug 54029: 66102 | 66103 | 66104 | 123387

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