lkml.org 
[lkml]   [2021]   [Jul]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[PATCH v2 1/3] binderfs: add support for feature files
From
Provide userspace with a mechanism to discover features supported by
the binder driver to refrain from using any unsupported ones in the
first place. Starting with "oneway_spam_detection" only new features
are to be listed under binderfs and all previous ones are assumed to
be supported.

Assuming an instance of binderfs has been mounted at /dev/binderfs,
binder feature files can be found under /dev/binderfs/features/.
Usage example:

$ mkdir /dev/binderfs
$ mount -t binder binder /dev/binderfs
$ cat /dev/binderfs/features/oneway_spam_detection
1

Signed-off-by: Carlos Llamas <cmllamas@google.com>
---
drivers/android/binderfs.c | 39 ++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)

diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index e80ba93c62a9..e3605cdd4335 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -58,6 +58,10 @@ enum binderfs_stats_mode {
binderfs_stats_mode_global,
};

+struct binder_features {
+ bool oneway_spam_detection;
+};
+
static const struct constant_table binderfs_param_stats[] = {
{ "global", binderfs_stats_mode_global },
{}
@@ -69,6 +73,10 @@ static const struct fs_parameter_spec binderfs_fs_parameters[] = {
{}
};

+static struct binder_features binder_features = {
+ .oneway_spam_detection = true,
+};
+
static inline struct binderfs_info *BINDERFS_SB(const struct super_block *sb)
{
return sb->s_fs_info;
@@ -583,6 +591,33 @@ static struct dentry *binderfs_create_dir(struct dentry *parent,
return dentry;
}

+static int binder_features_show(struct seq_file *m, void *unused)
+{
+ bool *feature = m->private;
+
+ seq_printf(m, "%d\n", *feature);
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(binder_features);
+
+static int init_binder_features(struct super_block *sb)
+{
+ struct dentry *dentry, *dir;
+
+ dir = binderfs_create_dir(sb->s_root, "features");
+ if (IS_ERR(dir))
+ return PTR_ERR(dir);
+
+ dentry = binderfs_create_file(dir, "oneway_spam_detection",
+ &binder_features_fops,
+ &binder_features.oneway_spam_detection);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+
+ return 0;
+}
+
static int init_binder_logs(struct super_block *sb)
{
struct dentry *binder_logs_root_dir, *dentry, *proc_log_dir;
@@ -723,6 +758,10 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc)
name++;
}

+ ret = init_binder_features(sb);
+ if (ret)
+ return ret;
+
if (info->mount_opts.stats_mode == binderfs_stats_mode_global)
return init_binder_logs(sb);

--
2.32.0.93.g670b81a890-goog
\
 
 \ /
  Last update: 2021-07-15 05:19    [W:0.223 / U:0.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site