Vold is the volume daemon in Android that manages storage volumes like external SD cards. It communicates with the Linux kernel via Netlink sockets to receive storage events and with the MountService via a local socket. When a new storage device is inserted, Vold receives the kernel event, mounts the volume if FAT format according to its configuration file, and notifies MountService to make the volume available to the user.
I have tried to present maximum detail on android booting sequence in a very abstract way. I hope it would be useful. If you find any correction needed please mention it on comments. Happy Coding :)
Android graphic system (SurfaceFlinger) : Design Pattern's perspectiveBin Chen
SurfaceFlinger is a vital system service in Android system, responsible for the composting all the application and system layer and displaying them. In this slide,we looked in detail how surfaceFlinger was designed from Design Pattern's perspective.
Embedded Android system development workshop is focused on integrating new device with Android framework. Our hands-on approach makes Emertxe as the best institute to learn android system development training. This workshop deep dives into Android porting, Android Hardware Abstraction Layer (HAL), Android Services and Linux device driver ecosystem. This workshop based training program will enable you to efficiently integrate new hardware with Android HAL / Framework.
This presentation covers the working model about Process, Thread, system call, Memory operations, Binder IPC, and interactions with Android frameworks.
Device Tree Overlay implementation on AOSP 9.0Cheng Wig
With the popularity of Android phones, along with the success in the consumer field, the industrial Android platform is also becoming more and more popular in Europe.
In this session, the presenter will share his experience of integrating AOSP 9.0 on multiple industrial grade platform with various hardware specifications, as well as demonstrate a real case of using the latest dtbo.img architecture to achieve separating the hardware specifications from the software definitions. With this additional abstract layer, the maintenance costs and upgrade complexity will be dramatically improved while fully matching the security architecture of AOSP.
For new age touch-based embedded devices, Android is becoming a popular OS going beyond mobile phones. With its roots from Embedded Linux, Android framework offers benefits in terms of rich libraries, open-source and multi-device support. Emertxe’s hands-on Embedded Android Training Course is designed to customize, build and deploy custom Embedded OS on ARM target. Rich set of projects will make your learning complete.
I have tried to present maximum detail on android booting sequence in a very abstract way. I hope it would be useful. If you find any correction needed please mention it on comments. Happy Coding :)
Android graphic system (SurfaceFlinger) : Design Pattern's perspectiveBin Chen
SurfaceFlinger is a vital system service in Android system, responsible for the composting all the application and system layer and displaying them. In this slide,we looked in detail how surfaceFlinger was designed from Design Pattern's perspective.
Embedded Android system development workshop is focused on integrating new device with Android framework. Our hands-on approach makes Emertxe as the best institute to learn android system development training. This workshop deep dives into Android porting, Android Hardware Abstraction Layer (HAL), Android Services and Linux device driver ecosystem. This workshop based training program will enable you to efficiently integrate new hardware with Android HAL / Framework.
This presentation covers the working model about Process, Thread, system call, Memory operations, Binder IPC, and interactions with Android frameworks.
Device Tree Overlay implementation on AOSP 9.0Cheng Wig
With the popularity of Android phones, along with the success in the consumer field, the industrial Android platform is also becoming more and more popular in Europe.
In this session, the presenter will share his experience of integrating AOSP 9.0 on multiple industrial grade platform with various hardware specifications, as well as demonstrate a real case of using the latest dtbo.img architecture to achieve separating the hardware specifications from the software definitions. With this additional abstract layer, the maintenance costs and upgrade complexity will be dramatically improved while fully matching the security architecture of AOSP.
For new age touch-based embedded devices, Android is becoming a popular OS going beyond mobile phones. With its roots from Embedded Linux, Android framework offers benefits in terms of rich libraries, open-source and multi-device support. Emertxe’s hands-on Embedded Android Training Course is designed to customize, build and deploy custom Embedded OS on ARM target. Rich set of projects will make your learning complete.
You want to learn what virtualization is all about? I’ll talk about high level concepts, tips and tricks and best practices. You will learn all that and even why Azure might be an interesting choice when we talk developer virtualization. Concepts like Sysprep, Differencing drives, snapshot intrigue you? I’ll let you know all about them and more! Come join me to explore all that virtualization as to offer
Solaris 10 and 11 Installation, Management and Monitoring made easy. Central Management Server with support for automated deployment of LDoms and Zones
The manual of the GTK+ 2.0 application - Desktop App Chooser which let the user to browse all installed X desktop applications and retrieve the Desktop Entry content of each application.
"Impact of front-end architecture on development cost", Viktor TurskyiFwdays
I have heard many times that architecture is not important for the front-end. Also, many times I have seen how developers implement features on the front-end just following the standard rules for a framework and think that this is enough to successfully launch the project, and then the project fails. How to prevent this and what approach to choose? I have launched dozens of complex projects and during the talk we will analyze which approaches have worked for me and which have not.
State of ICS and IoT Cyber Threat Landscape Report 2024 previewPrayukth K V
The IoT and OT threat landscape report has been prepared by the Threat Research Team at Sectrio using data from Sectrio, cyber threat intelligence farming facilities spread across over 85 cities around the world. In addition, Sectrio also runs AI-based advanced threat and payload engagement facilities that serve as sinks to attract and engage sophisticated threat actors, and newer malware including new variants and latent threats that are at an earlier stage of development.
The latest edition of the OT/ICS and IoT security Threat Landscape Report 2024 also covers:
State of global ICS asset and network exposure
Sectoral targets and attacks as well as the cost of ransom
Global APT activity, AI usage, actor and tactic profiles, and implications
Rise in volumes of AI-powered cyberattacks
Major cyber events in 2024
Malware and malicious payload trends
Cyberattack types and targets
Vulnerability exploit attempts on CVEs
Attacks on counties – USA
Expansion of bot farms – how, where, and why
In-depth analysis of the cyber threat landscape across North America, South America, Europe, APAC, and the Middle East
Why are attacks on smart factories rising?
Cyber risk predictions
Axis of attacks – Europe
Systemic attacks in the Middle East
Download the full report from here:
https://sectrio.com/resources/ot-threat-landscape-reports/sectrio-releases-ot-ics-and-iot-security-threat-landscape-report-2024/
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
2. Outline
What is Vold?
Components
Communication
Vold Init Flow
Volume State Machine
Example : SD Card Insert
Appendix A- An issue in Google original code
Appendix B- How to read Microsoft NTFS format
storage?
Reference
3. What is Vold?
Volume daemon
The same as Mountd before Donut (Android 1.7)
Vold 2.0 since Froyo (Android 2.2)
As the role of Udev in the desktop Linux distro
Lisenting Netlink socket for volume changing Uevent
Ineteract with MountService (Java layer)
As a slave to MountService which is the decision maker
Notify volume status changing events to MountService
Execute commands issued from MountService
Communicates with MountService through unix domain(POSIX
Local IPC) socket
Folder : AndroidSrc/system/vold
Main Entry
main.c : main()
11. Components (8/12)
Volume / DirectVolume
Volume.cpp/.h , DirectVolume.cpp/.h
DirectVolume is a subclass of Volume
To store volume informations retreiving from vold.fstab
Volume do the actual actions(mount, unmount, etc)
corresponding to the commands(doMount, doUnmount, etc)
from MountService
12. Components (9/12)
vold.fstab
AndroidSrc/device/nvidia/ventana [nVidia solution]
Describe what storages will be added into system
Processed by process_config()
AndroidSrc/system/vold/main.cpp
Example:
dev_mount usbdrive /mnt/usbdrive auto /devices/platform/tegra-ehci.2/usb2
dev_mount - Means mounting devices
usbdrive - Label for the USB volume
/mnt/usbdrive - Where the USB volume will be mounted
auto - Partition number (1 based). 'auto' for first usable partition
/devices/platform/tegra-ehci.2/usb2 - The sysfs path to external USB device
13. Components (10/12)
Fat
Fat.cpp/.h
Validate if the filesystem of the new added volume is FAT
Mount the new volume whose filesystem type is FAT
Format specified volume’s filesystem to FAT
16. Communication
Netlink Socket
Passes informations between Kernel space and User
space
Protocol : NETLINK_KOBJECT_UEVENT
Defined in KernelSrc/include/linux/netlink.h
KernelSrc/lib/kobject_uevent.c : kobject_uevent_env()
Unix Domain/POSIX Local IPC Socket
For the communication between Vold & MountService
Created in init.rc
socket vold stream 0660 root mount
mount is MountService process
AndroidSrc/system/core/rootdir/init.rc
17. Vold Init Flow
Init.rc invoke “/system/bin/vold” &
create local socket “vold”
vold/main()
Create instance of
VolumeManager, CommandListener,
NetlinkManager separately
Set CommandLisener instance
to be the broadcaster of
VolumeManager/NetlinkManager to notify
volume changing event to MountService
through local socket
Activate the VolumeManager instance to run
Create the folder “/dev/block/vold” for device
node of new added volume
Acitvate the NetlinkManager instance to
listen to netlink uevent
Call coldboot() to monitor if there has
any volume(insternal/external storage)
has existed before booting
start
Activate CommandLinstener instance to
to listen “vold” local socket
Loop forever
Parse vold.fstab and store possible adding
storages’ Information using DirectVolume
18. Volume State Machine (1/4)
10 volume states (enum-value)
Init (-1)
NoMedia/Removed (0)
Idle/Unmounted (1)
Pending (2)
Waiting for the report of the number of volume partition
Chencking (3)
Checking filesystem type
Mounted (4)
Unmounting (5)
Formatting (6)
Shared(Unmounted) (7)
ShareMnt (8)
19. Volume State Machine (2/4)
Init NoMediaInitial
System initialize done
Attach storage to the device
NoMedia
Idle(Unmounted)
Pending
CheckingMounted
Initial
20. Volume State Machine (3/4)
NoMedia Idle(Unmounted)
Initial
Deattach storage from the device
Mounted Unmounting
Formatting
Idle(Unmounted)
Initial
Format the storage
Mounted Unmounting
(1)
(2) (3)
(4)(5)
CheckingMounted
(6)
21. Volume State Machine (4/4)
Idle(Unmounted)
Initial
Storage(SD card) Unsharing
SharedMnt Shared-Unmounted
CheckingMounted
Shared-Unmounted
Initial
Storage(SD card) Sharing
Mounted Unmounting
Idle(Unmounted)
SharedMnt
From Honeycomb with
MTP, these two cases
will not happen!
When access USB
mass-storage through
MTP, it need not to
unmount SD card.
22. Example: SD Card Insert (1/3)
[Honeycomb MR2]
Volume information for SD card in vold.fstab :
dev_mount sdcard /sdcard2 auto /devices/platform/sdhci-tegra.2/mmc_host/mmc1
When Vold init, a DirectVolume instance will be created to store SD card volume
informations
The stored informations are:
Label : sdcard
MountPoint : /sdcard2
DevPath(sysfs) : /devices/platform/sdhci-tegra.2/mmc_host/mmc1
23. Example: SD Card Insert (2/3)
Kernel detect a mmc
medium (sd card) insert
Kernel send Netlink Kobject Uevent :
ACTION : add
DEVPATH : /devices/platform/sdhci-
tegra.2/mmc_host/mmc1/mmc1:e624/block/mmcblk1
DEVTYPE : disk
SUBSYS : block
ACTION : add
DEVPATH : /devices/platform/sdhci-
tegra.2/mmc_host/mmc1/mmc1:e624/block/mmcblk1/mmcblk1p1
DEVTYPE : partition
SUBSYS : block
NetlinkHanlder detect Uevent with “block” subsys type,
then call VolumeManager::handleBlockEvent()
In VolumeManager::handleBlockEvent(), it iterate all
stored DirectVolume instances and call their
handleBolckEvent() method
In DirectVolume::handleBolckEvent(), it compares
passed in devPath with the one retrieved from vold.fstab.
In this example, if it found the string
“/devices/platform/sdhci-tegra.2/mmc_host/mmc1” in
devPath, it will create a device node under
/dev/block/vold/MajrID:MinrID for the new added volume
and then send notification,
“ResponseCode::VolumeDiskInserted”, to
MountService with Label & MountPoint (from vold.fstab)
as parameters
Continued to the
next slide
Insert
Android Device
24. Example: SD Card Insert (3/3)
On MountService receiving notification from
Vold, “ResponseCode::VolumeDiskInserted”,
it send “volume mount” command back to Vold
with “MountPoint” as the parameter named
Label
Continued from the previous slide
In Vold, CommandListener receive ”volume
mount” command, it execute
VolumeManager::mountVolume() with
parameter, Label, from MountService
In VolumeManager::mountVolume(), it
compare parameter, Label, with “Label” or
“MountPoint” informations retrieved from
vold.fstab.
If it match one of two information, it will call
Volume::mountVol() to subsequtial operations
for mounting
In Volume::mountVol(), it does FAT filesystem
checking operation by calling Fat::check().
If the new added volume is FAT filesystem, it
will try to mount new volume with VFAT type
using Fat::doMount() and
Volume::doMoveMount()
The new added volume has been mounted,
and the user can use this new
volume/storage (^o^)
25. Appendix A-
An issue in Google original code:
video/image files in external storage will be deleted
when un-mounting external storage
2011-10-14
26. Problem Description
After user pressing “Unmount” button in
Settings>Storage menu to unmount an
external storage, all video/image files on that
external storage will be deleted immediately
without any warning message
This problem will shock users!!!
27. Root Cause (1/2)
After user pressing “Unmount” button in
Settings>Storage menu, the system will send
ACTION_MEDIA_EJECT and
ACTION_MEDIA_UNMOUNTED Intents (events)
in sequence
When the member "mUnmountReceiver“
(BroadcastReceiver) of the class MediaProvider
(MediaProvider.java) receiving the
ACTION_MEDIA_EJECT Intent, it will call
delete() of SQLiteDatabase class to
prune/remove invalid entries in thumbnail table
representing video/image files on the
unmounted external storage
28. Root Cause (2/2)
delete() of SQLiteDatabase class will delete the
(video/image) files corresponding to invalid
entries in the thumbnail table eventually
Please refer to the Google Android issue
http://code.google.com/p/android/issues/detail?id=3692
Search the keyword “delete()”
29. Solution
To change the Intent type the member
"mUnmountReceiver“ monitors to
ACTION_MEDIA_UNMOUNTED and
ACTION_MEDIA_BAD_REMOVAL
So MediaProvider will prune/remove invalid
entries in thumbnail table only when it receives
Unmounted or Bad-Removal events
e.g. the external storage has been detached from the
file system actually!
31. Problem Description
Originally, Google Android only supports
Microsoft FAT format storage
Android Vold (Volume.cpp) checks the format
of a new inserted storage when trying to do
mounting. If it is not FAT format, it will skip this
storage and check the next found storage
Storages in NTFS format are so common, so it is
better for an Android device to be capable of
reading NTFS format storage
32. Solution (1/2)
TuxEra’s NTFS-3G is a stable, full-featured
solution to address the requirement of reading
NTFS format storage
This is a file system driver for NTFS format
After installing this into Linux system, it will add a file
system type option “ntfs” of “mount” system command
and “mount()” API
NTFS-3G official site
http://www.tuxera.com/community/ntfs-3g-download/
33. Solution (2/2)
In the method mountVol() of Volume class
(Volume.cpp)
“if ( Fat::check(devicePath) )” block will enter when the
checking status is non-zero, e.g. the current storage is
NOT FAT format
It could add codes to calling mount() with “ntfs” option
in this block to try to mount current storage and to see if
it is NTFS format through the return value of mount()
Also, it needs to check the storage is in Read-Only
mode
34. Reference
Kobject Uevent socket – Chapter 17, Linux 核
心開發指南 (Linux Kernel Development, 2/e)
Robert Love 著, 沈中庸、沈彥男 譯, 維科出版社
Unix Domain Socket – Chapter 15, Unix
Network Programming, Volume 1: The Sockets
Networking API, 3/e W. Richard Stevens
Netlink in Kernel –
http://www.linuxjournal.com/article/7356