binder: Support multiple context managers

Move the context manager state into a separate
struct context, and allow for each process to have
its own context associated with it.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Martijn Coenen <maco@google.com>
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Serban Constantinescu <serban.constantinescu@arm.com>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Cc: Rom Lemarchand <romlem@google.com>
Cc: Android Kernel Team <kernel-team@android.com>
Signed-off-by: Martijn Coenen <maco@google.com>
[jstultz: Minor checkpatch fix]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 38 insertions, 21 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 331d2abca9a2..59cb6d9ddbc0 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -56,8 +56,6 @@ static HLIST_HEAD(binder_dead_nodes);
 
 static struct dentry *binder_debugfs_dir_entry_root;
 static struct dentry *binder_debugfs_dir_entry_proc;
-static struct binder_node *binder_context_mgr_node;
-static kuid_t binder_context_mgr_uid = INVALID_UID;
 static int binder_last_id;
 
 #define BINDER_DEBUG_ENTRY(name) \
@@ -215,6 +213,15 @@ static struct binder_transaction_log_entry *binder_transaction_log_add(
         return e;
 }
 
+struct binder_context {
+        struct binder_node *binder_context_mgr_node;
+        kuid_t binder_context_mgr_uid;
+};
+
+static struct binder_context global_context = {
+        .binder_context_mgr_uid = INVALID_UID,
+};
+
 struct binder_work {
         struct list_head entry;
         enum {
@@ -330,6 +337,7 @@ struct binder_proc {
         int ready_threads;
         long default_priority;
         struct dentry *debugfs_entry;
+        struct binder_context *context;
 };
 
 enum {
@@ -934,8 +942,9 @@ static int binder_inc_node(struct binder_node *node, int strong, int internal,
                 if (internal) {
                         if (target_list == NULL &&
                             node->internal_strong_refs == 0 &&
-                            !(node == binder_context_mgr_node &&
-                            node->has_strong_ref)) {
+                            !(node->proc &&
+                              node == node->proc->context->binder_context_mgr_node &&
+                              node->has_strong_ref)) {
                                 pr_err("invalid inc strong node for %d\n",
                                         node->debug_id);
                                 return -EINVAL;
@@ -1036,6 +1045,7 @@ static struct binder_ref *binder_get_ref_for_node(struct binder_proc *proc,
         struct rb_node **p = &proc->refs_by_node.rb_node;
         struct rb_node *parent = NULL;
         struct binder_ref *ref, *new_ref;
+        struct binder_context *context = proc->context;
 
         while (*p) {
                 parent = *p;
@@ -1058,7 +1068,7 @@ static struct binder_ref *binder_get_ref_for_node(struct binder_proc *proc,
         rb_link_node(&new_ref->rb_node_node, parent, p);
         rb_insert_color(&new_ref->rb_node_node, &proc->refs_by_node);
 
-        new_ref->desc = (node == binder_context_mgr_node) ? 0 : 1;
+        new_ref->desc = (node == context->binder_context_mgr_node) ? 0 : 1;
         for (n = rb_first(&proc->refs_by_desc); n != NULL; n = rb_next(n)) {
                 ref = rb_entry(n, struct binder_ref, rb_node_desc);
                 if (ref->desc > new_ref->desc)
@@ -1388,6 +1398,7 @@ static void binder_transaction(struct binder_proc *proc,
         struct binder_transaction *in_reply_to = NULL;
         struct binder_transaction_log_entry *e;
         uint32_t return_error;
+        struct binder_context *context = proc->context;
 
         e = binder_transaction_log_add(&binder_transaction_log);
         e->call_type = reply ? 2 : !!(tr->flags & TF_ONE_WAY);
@@ -1448,7 +1459,7 @@ static void binder_transaction(struct binder_proc *proc,
                         }
                         target_node = ref->node;
                 } else {
-                        target_node = binder_context_mgr_node;
+                        target_node = context->binder_context_mgr_node;
                         if (target_node == NULL) {
                                 return_error = BR_DEAD_REPLY;
                                 goto err_no_context_mgr_node;
@@ -1839,6 +1850,7 @@ static int binder_thread_write(struct binder_proc *proc,
                         binder_size_t *consumed)
 {
         uint32_t cmd;
+        struct binder_context *context = proc->context;
         void __user *buffer = (void __user *)(uintptr_t)binder_buffer;
         void __user *ptr = buffer + *consumed;
         void __user *end = buffer + size;
@@ -1865,10 +1877,10 @@ static int binder_thread_write(struct binder_proc *proc,
                         if (get_user(target, (uint32_t __user *)ptr))
                                 return -EFAULT;
                         ptr += sizeof(uint32_t);
-                        if (target == 0 && binder_context_mgr_node &&
+                        if (target == 0 && context->binder_context_mgr_node &&
                             (cmd == BC_INCREFS || cmd == BC_ACQUIRE)) {
                                 ref = binder_get_ref_for_node(proc,
-                                               binder_context_mgr_node);
+                                        context->binder_context_mgr_node);
                                 if (ref->desc != target) {
                                         binder_user_error("%d:%d tried to acquire reference to desc 0, got %d instead\n",
                                                 proc->pid, thread->pid,
@@ -2774,9 +2786,11 @@ static int binder_ioctl_set_ctx_mgr(struct file *filp)
 {
         int ret = 0;
         struct binder_proc *proc = filp->private_data;
+        struct binder_context *context = proc->context;
+
         kuid_t curr_euid = current_euid();
 
-        if (binder_context_mgr_node != NULL) {
+        if (context->binder_context_mgr_node) {
                 pr_err("BINDER_SET_CONTEXT_MGR already set\n");
                 ret = -EBUSY;
                 goto out;
@@ -2784,27 +2798,27 @@ static int binder_ioctl_set_ctx_mgr(struct file *filp)
         ret = security_binder_set_context_mgr(proc->tsk);
         if (ret < 0)
                 goto out;
-        if (uid_valid(binder_context_mgr_uid)) {
-                if (!uid_eq(binder_context_mgr_uid, curr_euid)) {
+        if (uid_valid(context->binder_context_mgr_uid)) {
+                if (!uid_eq(context->binder_context_mgr_uid, curr_euid)) {
                         pr_err("BINDER_SET_CONTEXT_MGR bad uid %d != %d\n",
                                from_kuid(&init_user_ns, curr_euid),
                                from_kuid(&init_user_ns,
-                                        binder_context_mgr_uid));
+                                         context->binder_context_mgr_uid));
                         ret = -EPERM;
                         goto out;
                 }
         } else {
-                binder_context_mgr_uid = curr_euid;
+                context->binder_context_mgr_uid = curr_euid;
         }
-        binder_context_mgr_node = binder_new_node(proc, 0, 0);
-        if (binder_context_mgr_node == NULL) {
+        context->binder_context_mgr_node = binder_new_node(proc, 0, 0);
+        if (!context->binder_context_mgr_node) {
                 ret = -ENOMEM;
                 goto out;
         }
-        binder_context_mgr_node->local_weak_refs++;
-        binder_context_mgr_node->local_strong_refs++;
-        binder_context_mgr_node->has_strong_ref = 1;
-        binder_context_mgr_node->has_weak_ref = 1;
+        context->binder_context_mgr_node->local_weak_refs++;
+        context->binder_context_mgr_node->local_strong_refs++;
+        context->binder_context_mgr_node->has_strong_ref = 1;
+        context->binder_context_mgr_node->has_weak_ref = 1;
 out:
         return ret;
 }
@@ -3039,6 +3053,7 @@ static int binder_open(struct inode *nodp, struct file *filp)
         get_task_struct(current);
         proc->tsk = current;
         proc->vma_vm_mm = current->mm;
+        proc->context = &global_context;
         INIT_LIST_HEAD(&proc->todo);
         init_waitqueue_head(&proc->wait);
         proc->default_priority = task_nice(current);
@@ -3151,6 +3166,7 @@ static int binder_node_release(struct binder_node *node, int refs)
 static void binder_deferred_release(struct binder_proc *proc)
 {
         struct binder_transaction *t;
+        struct binder_context *context = proc->context;
         struct rb_node *n;
         int threads, nodes, incoming_refs, outgoing_refs, buffers,
                 active_transactions, page_count;
@@ -3160,11 +3176,12 @@ static void binder_deferred_release(struct binder_proc *proc)
 
         hlist_del(&proc->proc_node);
 
-        if (binder_context_mgr_node && binder_context_mgr_node->proc == proc) {
+        if (context->binder_context_mgr_node &&
+            context->binder_context_mgr_node->proc == proc) {
                 binder_debug(BINDER_DEBUG_DEAD_BINDER,
                              "%s: %d context_mgr_node gone\n",
                              __func__, proc->pid);
-                binder_context_mgr_node = NULL;
+                context->binder_context_mgr_node = NULL;
         }
 
         threads = 0;