924858cd18
This fixes a race condition where WaitForFile() after
GetDmDevicePathByName appears to succeed, but a subsequent operation on
the path fails. This can happen when CreateDevice() is called
immediately after a call to DeleteDevice (from any process), and the
path is re-used, enqueuing udev events to remove and re-add the block
device.
The fix for this is to introduce a new variant of CreateDevice() that
has a timeout parameter. When the timeout is positive, CreateDevice()
will wait for a /dev/block/mapper/by-uuid symlink to be created, which
signals that ueventd has finished processing the operation.
ueventd will now create these by-uuid symlinks for device-mapper nodes.
Unfortunately, the uuid is only available during "change" events, so we
have to special case device-mapper symlink creation. And since the uuid
is not available during "remove" events, we simply find matching links
to remove them.
This ensures that callers of CreateDevice() can use the device path
knowing that no asynchronous removals are pending. Code that uses the
old CreateDevice+WaitForFile pattern will be transitioned to the new
method.
Note that it is safe to ignore the timeout, or to use the "unsafe"
CreateDevice, if the caller ensures the path by other means. For example
first-stage init has no device removal, and regenerates uevents until
it has acquired all the paths it needs.
Finally, since libdm now inspects sysfs unconditionally, libdm consumers
need r_dir_file perms for sysfs_dm in their sepolicy. Additionally
linking to libdm now requires linking to libext2_uuid.
Bug: 135771280
Test: libdm_test
device flashes, boots
Change-Id: If5a7383ea38f32a7fbbcf24842dce6a668050a70
152 lines
3.5 KiB
Text
152 lines
3.5 KiB
Text
//
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// Copyright (C) 2017 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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cc_defaults {
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name: "fs_mgr_defaults",
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sanitize: {
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misc_undefined: ["integer"],
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},
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local_include_dirs: ["include/"],
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cflags: [
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"-Wall",
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"-Werror",
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],
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}
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cc_library {
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// Do not ever allow this library to be vendor_available as a shared library.
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// It does not have a stable interface.
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name: "libfs_mgr",
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defaults: ["fs_mgr_defaults"],
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recovery_available: true,
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export_include_dirs: ["include"],
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include_dirs: ["system/vold"],
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srcs: [
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"file_wait.cpp",
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"fs_mgr.cpp",
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"fs_mgr_format.cpp",
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"fs_mgr_verity.cpp",
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"fs_mgr_dm_linear.cpp",
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"fs_mgr_overlayfs.cpp",
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"fs_mgr_roots.cpp",
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"fs_mgr_vendor_overlay.cpp",
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],
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shared_libs: [
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"libbase",
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"libcrypto",
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"libcrypto_utils",
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"libcutils",
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"libext4_utils",
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"libfec",
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"liblog",
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"liblp",
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"libselinux",
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],
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static_libs: [
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"libavb",
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"libfs_avb",
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"libfstab",
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"libdm",
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"libgsi",
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],
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export_static_lib_headers: [
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"libfs_avb",
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"libfstab",
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"libdm",
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],
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export_shared_lib_headers: [
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"liblp",
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],
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whole_static_libs: [
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"liblogwrap",
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"libdm",
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"libext2_uuid",
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"libfstab",
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],
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cppflags: [
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"-DALLOW_ADBD_DISABLE_VERITY=0",
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],
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product_variables: {
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debuggable: {
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cppflags: [
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"-UALLOW_ADBD_DISABLE_VERITY",
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"-DALLOW_ADBD_DISABLE_VERITY=1",
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],
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},
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},
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}
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cc_library_static {
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// Do not ever make this a shared library as long as it is vendor_available.
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// It does not have a stable interface.
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name: "libfstab",
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vendor_available: true,
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recovery_available: true,
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host_supported: true,
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defaults: ["fs_mgr_defaults"],
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srcs: [
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"fs_mgr_fstab.cpp",
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"fs_mgr_boot_config.cpp",
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"fs_mgr_slotselect.cpp",
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],
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target: {
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darwin: {
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enabled: false,
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},
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},
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export_include_dirs: ["include_fstab"],
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header_libs: [
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"libbase_headers",
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"libgsi_headers",
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],
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}
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cc_binary {
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name: "remount",
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defaults: ["fs_mgr_defaults"],
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static_libs: [
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"libavb_user",
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],
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shared_libs: [
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"libbootloader_message",
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"libbase",
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"libcutils",
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"libcrypto",
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"libext4_utils",
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"libfec",
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"libfs_mgr",
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"liblog",
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"liblp",
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"libselinux",
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],
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header_libs: [
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"libcutils_headers",
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],
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srcs: [
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"fs_mgr_remount.cpp",
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],
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cppflags: [
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"-DALLOW_ADBD_DISABLE_VERITY=0",
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],
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product_variables: {
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debuggable: {
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cppflags: [
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"-UALLOW_ADBD_DISABLE_VERITY",
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"-DALLOW_ADBD_DISABLE_VERITY=1",
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],
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},
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},
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}
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