Currently, since each binderfs instance needs its own
private binder devices, every time a binderfs instance is
mounted, all the default binder devices need to be created
via the BINDER_CTL_ADD IOCTL. This patch aims to
add a solution to automatically create the default binder
devices for each binderfs instance that gets mounted.
To achieve this goal, when CONFIG_ANDROID_BINDERFS is set,
the default binder devices specified by CONFIG_ANDROID_BINDER_DEVICES
are created in each binderfs instance instead of global devices
being created by the binder driver.
Co-developed-by: Christian Brauner <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
Signed-off-by: Hridya Valsaraju <[email protected]>
---
Changes in v2:
- Updated commit message as per Greg Kroah-Hartman.
- Removed new module parameter creation as per Greg
Kroah-Hartman/Christian Brauner.
- Refactored device name length check into a new patch as per Greg Kroah-Hartman.
drivers/android/binder.c | 5 +++--
drivers/android/binder_internal.h | 2 ++
drivers/android/binderfs.c | 25 ++++++++++++++++++++++---
3 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 466b6a7f8ab7..ca6b21a53321 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -123,7 +123,7 @@ static uint32_t binder_debug_mask = BINDER_DEBUG_USER_ERROR |
BINDER_DEBUG_FAILED_TRANSACTION | BINDER_DEBUG_DEAD_TRANSACTION;
module_param_named(debug_mask, binder_debug_mask, uint, 0644);
-static char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
+char *binder_devices_param = CONFIG_ANDROID_BINDER_DEVICES;
module_param_named(devices, binder_devices_param, charp, 0444);
static DECLARE_WAIT_QUEUE_HEAD(binder_user_error_wait);
@@ -6279,7 +6279,8 @@ static int __init binder_init(void)
&transaction_log_fops);
}
- if (strcmp(binder_devices_param, "") != 0) {
+ if (!IS_ENABLED(CONFIG_ANDROID_BINDERFS) &&
+ strcmp(binder_devices_param, "") != 0) {
/*
* Copy the module_parameter string, because we don't want to
* tokenize it in-place.
diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h
index 045b3e42d98b..fe8c745dc8e0 100644
--- a/drivers/android/binder_internal.h
+++ b/drivers/android/binder_internal.h
@@ -37,6 +37,8 @@ struct binder_device {
extern const struct file_operations binder_fops;
+extern char *binder_devices_param;
+
#ifdef CONFIG_ANDROID_BINDERFS
extern bool is_binderfs_device(const struct inode *inode);
#else
diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index e773f45d19d9..886b4e0f482f 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -186,8 +186,7 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
req->major = MAJOR(binderfs_dev);
req->minor = minor;
- ret = copy_to_user(userp, req, sizeof(*req));
- if (ret) {
+ if (userp && copy_to_user(userp, req, sizeof(*req))) {
ret = -EFAULT;
goto err;
}
@@ -467,6 +466,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
int ret;
struct binderfs_info *info;
struct inode *inode = NULL;
+ struct binderfs_device device_info = { 0 };
+ const char *name;
+ size_t len;
sb->s_blocksize = PAGE_SIZE;
sb->s_blocksize_bits = PAGE_SHIFT;
@@ -521,7 +523,24 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
if (!sb->s_root)
return -ENOMEM;
- return binderfs_binder_ctl_create(sb);
+ ret = binderfs_binder_ctl_create(sb);
+ if (ret)
+ return ret;
+
+ name = binder_devices_param;
+ for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
+ strscpy(device_info.name, name, len + 1);
+ ret = binderfs_binder_device_create(inode, NULL, &device_info);
+ if (ret)
+ return ret;
+ name += len;
+ if (*name == ',')
+ name++;
+
+ }
+
+ return 0;
+
}
static struct dentry *binderfs_mount(struct file_system_type *fs_type,
--
2.22.0.770.g0f2c4a37fd-goog
On Tue, Aug 06, 2019 at 11:40:05AM -0700, Hridya Valsaraju wrote:
> @@ -467,6 +466,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> int ret;
> struct binderfs_info *info;
> struct inode *inode = NULL;
> + struct binderfs_device device_info = { 0 };
> + const char *name;
> + size_t len;
>
> sb->s_blocksize = PAGE_SIZE;
> sb->s_blocksize_bits = PAGE_SHIFT;
> @@ -521,7 +523,24 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> if (!sb->s_root)
> return -ENOMEM;
>
> - return binderfs_binder_ctl_create(sb);
> + ret = binderfs_binder_ctl_create(sb);
> + if (ret)
> + return ret;
> +
> + name = binder_devices_param;
> + for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> + strscpy(device_info.name, name, len + 1);
> + ret = binderfs_binder_device_create(inode, NULL, &device_info);
> + if (ret)
> + return ret;
We should probably clean up before returning... The error handling code
would probably be tricky to write though and it's not super common.
> + name += len;
> + if (*name == ',')
> + name++;
> +
> + }
> +
> + return 0;
> +
Remove this extra blank line.
> }
regards,
dan carpenter
On Wed, Aug 7, 2019 at 4:02 AM Dan Carpenter <[email protected]> wrote:
>
> On Tue, Aug 06, 2019 at 11:40:05AM -0700, Hridya Valsaraju wrote:
> > @@ -467,6 +466,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> > int ret;
> > struct binderfs_info *info;
> > struct inode *inode = NULL;
> > + struct binderfs_device device_info = { 0 };
> > + const char *name;
> > + size_t len;
> >
> > sb->s_blocksize = PAGE_SIZE;
> > sb->s_blocksize_bits = PAGE_SHIFT;
> > @@ -521,7 +523,24 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> > if (!sb->s_root)
> > return -ENOMEM;
> >
> > - return binderfs_binder_ctl_create(sb);
> > + ret = binderfs_binder_ctl_create(sb);
> > + if (ret)
> > + return ret;
> > +
> > + name = binder_devices_param;
> > + for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> > + strscpy(device_info.name, name, len + 1);
> > + ret = binderfs_binder_device_create(inode, NULL, &device_info);
> > + if (ret)
> > + return ret;
>
> We should probably clean up before returning... The error handling code
> would probably be tricky to write though and it's not super common.
Thank you for taking a look Dan. Did you mean cleaning up the default
devices that were already created? They will actually be cleaned up by
binderfs_evict_inode() during the super block's cleanup since the
mount operation will fail due to an error here.
>
> > + name += len;
> > + if (*name == ',')
> > + name++;
> > +
> > + }
> > +
> > + return 0;
> > +
>
> Remove this extra blank line.
Will do in v3, thanks for catching this Dan!
>
> > }
>
> regards,
> dan carpenter
>
> --
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
>
On Wed, Aug 07, 2019 at 02:02:05PM +0300, Dan Carpenter wrote:
> On Tue, Aug 06, 2019 at 11:40:05AM -0700, Hridya Valsaraju wrote:
> > @@ -467,6 +466,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> > int ret;
> > struct binderfs_info *info;
> > struct inode *inode = NULL;
> > + struct binderfs_device device_info = { 0 };
> > + const char *name;
> > + size_t len;
> >
> > sb->s_blocksize = PAGE_SIZE;
> > sb->s_blocksize_bits = PAGE_SHIFT;
> > @@ -521,7 +523,24 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> > if (!sb->s_root)
> > return -ENOMEM;
> >
> > - return binderfs_binder_ctl_create(sb);
> > + ret = binderfs_binder_ctl_create(sb);
> > + if (ret)
> > + return ret;
> > +
> > + name = binder_devices_param;
> > + for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> > + strscpy(device_info.name, name, len + 1);
> > + ret = binderfs_binder_device_create(inode, NULL, &device_info);
> > + if (ret)
> > + return ret;
>
> We should probably clean up before returning... The error handling code
> would probably be tricky to write though and it's not super common.
struct dentry *mount_nodev(struct file_system_type *fs_type,
int flags, void *data,
int (*fill_super)(struct super_block *, void *, int))
{
<snip>
error = fill_super(s, data, flags & SB_SILENT ? 1 : 0);
if (error) {
deactivate_locked_super(s);
return ERR_PTR(error);
}
<snip>
}
deactivate_locked_super()
will call
fs->kill_sb(s)
which calls
binderfs_kill_super()
which calls
kill_litter_super()
the latter will destory any remaining dentries and then calls
generic_shutdown_super()
which calls
evict_inodes()
which calls
evict(inode)
which calls the binderfs specific
binderfs_evict_inode()
and get rid of the rest.
So manually cleaning up is not needed, imho.
Christian
On Wed, Aug 07, 2019 at 09:51:46AM -0700, Hridya Valsaraju wrote:
> On Wed, Aug 7, 2019 at 4:02 AM Dan Carpenter <[email protected]> wrote:
> >
> > On Tue, Aug 06, 2019 at 11:40:05AM -0700, Hridya Valsaraju wrote:
> > > @@ -467,6 +466,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> > > int ret;
> > > struct binderfs_info *info;
> > > struct inode *inode = NULL;
> > > + struct binderfs_device device_info = { 0 };
> > > + const char *name;
> > > + size_t len;
> > >
> > > sb->s_blocksize = PAGE_SIZE;
> > > sb->s_blocksize_bits = PAGE_SHIFT;
> > > @@ -521,7 +523,24 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
> > > if (!sb->s_root)
> > > return -ENOMEM;
> > >
> > > - return binderfs_binder_ctl_create(sb);
> > > + ret = binderfs_binder_ctl_create(sb);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + name = binder_devices_param;
> > > + for (len = strcspn(name, ","); len > 0; len = strcspn(name, ",")) {
> > > + strscpy(device_info.name, name, len + 1);
> > > + ret = binderfs_binder_device_create(inode, NULL, &device_info);
> > > + if (ret)
> > > + return ret;
> >
> > We should probably clean up before returning... The error handling code
> > would probably be tricky to write though and it's not super common.
>
> Thank you for taking a look Dan. Did you mean cleaning up the default
> devices that were already created? They will actually be cleaned up by
> binderfs_evict_inode() during the super block's cleanup since the
> mount operation will fail due to an error here.
Yeah. I meant the binderfs_binder_device_create() from previous
iterations through this loop.
Good to know that it's handled. Thanks for taking the time to look at
this.
regards,
dan carpenter