block: Add permissions to blk_new()

We want every user to be specific about the permissions it needs, so
we'll pass the initial permissions as parameters to blk_new(). A user
only needs to call blk_set_perm() if it wants to change the permissions
after the fact.

The permissions are stored in the BlockBackend and applied whenever a
BlockDriverState should be attached in blk_insert_bs().

This does not include actually choosing the right set of permissions
everywhere yet. Instead, the usual FIXME comment is added to each place
and will be addressed in individual patches.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Acked-by: Fam Zheng <famz@redhat.com>

18 files changed, 53 insertions, 30 deletions

diff --git a/block.c b/block.c
index bed236747a..41b8b11424 100644
--- a/block.c
+++ b/block.c
@@ -2193,7 +2193,7 @@ static BlockDriverState *bdrv_open_inherit(const char *filename,
             goto fail;
         }
         if (file_bs != NULL) {
-            file = blk_new();
+            file = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL);
             blk_insert_bs(file, file_bs);
             bdrv_unref(file_bs);
 
diff --git a/block/backup.c b/block/backup.c
index fe010e78e3..4b3c94c812 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -624,7 +624,8 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
         goto error;
     }
 
-    job->target = blk_new();
+    /* FIXME Use real permissions */
+    job->target = blk_new(0, BLK_PERM_ALL);
     blk_insert_bs(job->target, target);
 
     job->on_source_error = on_source_error;
diff --git a/block/block-backend.c b/block/block-backend.c
index 1ed75c6c15..0319220a78 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -120,17 +120,23 @@ static const BdrvChildRole child_root = {
 
 /*
  * Create a new BlockBackend with a reference count of one.
- * Store an error through @errp on failure, unless it's null.
+ *
+ * @perm is a bitmasks of BLK_PERM_* constants which describes the permissions
+ * to request for a block driver node that is attached to this BlockBackend.
+ * @shared_perm is a bitmask which describes which permissions may be granted
+ * to other users of the attached node.
+ * Both sets of permissions can be changed later using blk_set_perm().
+ *
  * Return the new BlockBackend on success, null on failure.
  */
-BlockBackend *blk_new(void)
+BlockBackend *blk_new(uint64_t perm, uint64_t shared_perm)
 {
     BlockBackend *blk;
 
     blk = g_new0(BlockBackend, 1);
     blk->refcnt = 1;
-    blk->perm = 0;
-    blk->shared_perm = BLK_PERM_ALL;
+    blk->perm = perm;
+    blk->shared_perm = shared_perm;
     blk_set_enable_write_cache(blk, true);
 
     qemu_co_queue_init(&blk->public.throttled_reqs[0]);
@@ -161,7 +167,7 @@ BlockBackend *blk_new_open(const char *filename, const char *reference,
     BlockBackend *blk;
     BlockDriverState *bs;
 
-    blk = blk_new();
+    blk = blk_new(0, BLK_PERM_ALL);
     bs = bdrv_open(filename, reference, options, flags, errp);
     if (!bs) {
         blk_unref(blk);
@@ -505,9 +511,10 @@ void blk_remove_bs(BlockBackend *blk)
 void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs)
 {
     bdrv_ref(bs);
-    /* FIXME Use real permissions */
+    /* FIXME Error handling */
     blk->root = bdrv_root_attach_child(bs, "root", &child_root,
-                                       0, BLK_PERM_ALL, blk, &error_abort);
+                                       blk->perm, blk->shared_perm, blk,
+                                       &error_abort);
 
     notifier_list_notify(&blk->insert_bs_notifiers, blk);
     if (blk->public.throttle_state) {
diff --git a/block/commit.c b/block/commit.c
index c284e8535d..1897e982c5 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -275,10 +275,12 @@ void commit_start(const char *job_id, BlockDriverState *bs,
         block_job_add_bdrv(&s->common, overlay_bs);
     }
 
-    s->base = blk_new();
+    /* FIXME Use real permissions */
+    s->base = blk_new(0, BLK_PERM_ALL);
     blk_insert_bs(s->base, base);
 
-    s->top = blk_new();
+    /* FIXME Use real permissions */
+    s->top = blk_new(0, BLK_PERM_ALL);
     blk_insert_bs(s->top, top);
 
     s->active = bs;
@@ -328,10 +330,12 @@ int bdrv_commit(BlockDriverState *bs)
         }
     }
 
-    src = blk_new();
+    /* FIXME Use real permissions */
+    src = blk_new(0, BLK_PERM_ALL);
     blk_insert_bs(src, bs);
 
-    backing = blk_new();
+    /* FIXME Use real permissions */
+    backing = blk_new(0, BLK_PERM_ALL);
     blk_insert_bs(backing, bs->backing->bs);
 
     length = blk_getlength(src);
diff --git a/block/mirror.c b/block/mirror.c
index 1b34b366d0..30398fb857 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1017,7 +1017,8 @@ static void mirror_start_job(const char *job_id, BlockDriverState *bs,
         return;
     }
 
-    s->target = blk_new();
+    /* FIXME Use real permissions */
+    s->target = blk_new(0, BLK_PERM_ALL);
     blk_insert_bs(s->target, target);
 
     s->replaces = g_strdup(replaces);
diff --git a/block/qcow2.c b/block/qcow2.c
index ef028f64fb..0356e69e4e 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -3262,7 +3262,7 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
     }
 
     if (new_size) {
-        BlockBackend *blk = blk_new();
+        BlockBackend *blk = blk_new(BLK_PERM_RESIZE, BLK_PERM_ALL);
         blk_insert_bs(blk, bs);
         ret = blk_truncate(blk, new_size);
         blk_unref(blk);
diff --git a/blockdev.c b/blockdev.c
index 8682bd81d8..cd5642dd2e 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -558,7 +558,7 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
     if ((!file || !*file) && !qdict_size(bs_opts)) {
         BlockBackendRootState *blk_rs;
 
-        blk = blk_new();
+        blk = blk_new(0, BLK_PERM_ALL);
         blk_rs = blk_get_root_state(blk);
         blk_rs->open_flags    = bdrv_flags;
         blk_rs->read_only     = read_only;
@@ -2890,7 +2890,7 @@ void qmp_block_resize(bool has_device, const char *device,
         goto out;
     }
 
-    blk = blk_new();
+    blk = blk_new(BLK_PERM_RESIZE, BLK_PERM_ALL);
     blk_insert_bs(blk, bs);
 
     /* complete all in-flight operations before resizing the device */
diff --git a/blockjob.c b/blockjob.c
index abee11bb08..508e0e5069 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -159,7 +159,8 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
         }
     }
 
-    blk = blk_new();
+    /* FIXME Use real permissions */
+    blk = blk_new(0, BLK_PERM_ALL);
     blk_insert_bs(blk, bs);
 
     job = g_malloc0(driver->instance_size);
diff --git a/hmp.c b/hmp.c
index 83e287e0a4..020141b344 100644
--- a/hmp.c
+++ b/hmp.c
@@ -2050,7 +2050,8 @@ void hmp_qemu_io(Monitor *mon, const QDict *qdict)
     if (!blk) {
         BlockDriverState *bs = bdrv_lookup_bs(NULL, device, &err);
         if (bs) {
-            blk = local_blk = blk_new();
+            /* FIXME Use real permissions */
+            blk = local_blk = blk_new(0, BLK_PERM_ALL);
             blk_insert_bs(blk, bs);
         } else {
             goto fail;
diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index 17d29e7bc5..74f36344f6 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -533,7 +533,8 @@ static int floppy_drive_init(DeviceState *qdev)
 
     if (!dev->conf.blk) {
         /* Anonymous BlockBackend for an empty drive */
-        dev->conf.blk = blk_new();
+        /* FIXME Use real permissions */
+        dev->conf.blk = blk_new(0, BLK_PERM_ALL);
         ret = blk_attach_dev(dev->conf.blk, qdev);
         assert(ret == 0);
     }
diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index 94f4d8bde4..cca4775fc7 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -78,7 +78,8 @@ static void parse_drive(DeviceState *dev, const char *str, void **ptr,
     if (!blk) {
         BlockDriverState *bs = bdrv_lookup_bs(NULL, str, NULL);
         if (bs) {
-            blk = blk_new();
+            /* FIXME Use real permissions */
+            blk = blk_new(0, BLK_PERM_ALL);
             blk_insert_bs(blk, bs);
             blk_created = true;
         }
diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c
index dbaa75cf59..bb3c377800 100644
--- a/hw/ide/qdev.c
+++ b/hw/ide/qdev.c
@@ -170,7 +170,8 @@ static int ide_dev_initfn(IDEDevice *dev, IDEDriveKind kind)
             return -1;
         } else {
             /* Anonymous BlockBackend for an empty drive */
-            dev->conf.blk = blk_new();
+            /* FIXME Use real permissions */
+            dev->conf.blk = blk_new(0, BLK_PERM_ALL);
         }
     }
 
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index bbfb5dc289..546acc7b62 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -2380,7 +2380,8 @@ static void scsi_cd_realize(SCSIDevice *dev, Error **errp)
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, dev);
 
     if (!dev->conf.blk) {
-        dev->conf.blk = blk_new();
+        /* FIXME Use real permissions */
+        dev->conf.blk = blk_new(0, BLK_PERM_ALL);
     }
 
     s->qdev.blocksize = 2048;
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 4a18e86b85..6651f437db 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -84,7 +84,7 @@ typedef struct BlockBackendPublic {
     QLIST_ENTRY(BlockBackendPublic) round_robin;
 } BlockBackendPublic;
 
-BlockBackend *blk_new(void);
+BlockBackend *blk_new(uint64_t perm, uint64_t shared_perm);
 BlockBackend *blk_new_open(const char *filename, const char *reference,
                            QDict *options, int flags, Error **errp);
 int blk_get_refcnt(BlockBackend *blk);
diff --git a/migration/block.c b/migration/block.c
index ebc10e628d..6b7ffd4eb6 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -415,7 +415,8 @@ static void init_blk_migration(QEMUFile *f)
         }
 
         bmds = g_new0(BlkMigDevState, 1);
-        bmds->blk = blk_new();
+        /* FIXME Use real permissions */
+        bmds->blk = blk_new(0, BLK_PERM_ALL);
         bmds->blk_name = g_strdup(bdrv_get_device_name(bs));
         bmds->bulk_completed = 0;
         bmds->total_sectors = sectors;
diff --git a/nbd/server.c b/nbd/server.c
index ac92fa0727..936d5aa465 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -892,7 +892,8 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
     BlockBackend *blk;
     NBDExport *exp = g_malloc0(sizeof(NBDExport));
 
-    blk = blk_new();
+    /* FIXME Use real permissions */
+    blk = blk_new(0, BLK_PERM_ALL);
     blk_insert_bs(blk, bs);
     blk_set_enable_write_cache(blk, !writethrough);
 
diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
index 068c9e419b..1dd1cfa45a 100644
--- a/tests/test-blockjob.c
+++ b/tests/test-blockjob.c
@@ -53,7 +53,8 @@ static BlockJob *do_test_id(BlockBackend *blk, const char *id,
  * BlockDriverState inserted. */
 static BlockBackend *create_blk(const char *name)
 {
-    BlockBackend *blk = blk_new();
+    /* FIXME Use real permissions */
+    BlockBackend *blk = blk_new(0, BLK_PERM_ALL);
     BlockDriverState *bs;
 
     bs = bdrv_open("null-co://", NULL, NULL, 0, &error_abort);
diff --git a/tests/test-throttle.c b/tests/test-throttle.c
index 363b59a38f..5846433c9f 100644
--- a/tests/test-throttle.c
+++ b/tests/test-throttle.c
@@ -593,9 +593,10 @@ static void test_groups(void)
     BlockBackend *blk1, *blk2, *blk3;
     BlockBackendPublic *blkp1, *blkp2, *blkp3;
 
-    blk1 = blk_new();
-    blk2 = blk_new();
-    blk3 = blk_new();
+    /* FIXME Use real permissions */
+    blk1 = blk_new(0, BLK_PERM_ALL);
+    blk2 = blk_new(0, BLK_PERM_ALL);
+    blk3 = blk_new(0, BLK_PERM_ALL);
 
     blkp1 = blk_get_public(blk1);
     blkp2 = blk_get_public(blk2);