[Q] Storage Symlink - Android Q&A, Help & Troubleshooting

I am using an unrooted Nexus 5. I am familiar with the public and private data directories in Android.
My question is related to /storage/emulated/legacy. First I see multiple symlinks to this location. Second it is strangely mirrored by /storage/emulated/0.
My real question is this location a hard link with /data/media/0? I cannot see this as I am not rooted. I am asking because I know Android only encrypts /data. I want to make sure the public directories are also encrypted.

This forum moves fast...
Anyway, considering this question can be answered by anyone with root... I assume this one should be answerable.

Related

Need help with basic java!

Hi Everyone,
I am trying to code my first android app, which is an app that will copy some files from the app's asset folder to /system/app, adjust permissions and let the user know the process has been finished. I am a systems person, not a programmer, so know all of the details as to what has to get done. I create some scripts in /assets, and have the files I want to copy in /assets as well.
How do I go about programming this? Is this the right method I'm looking at doing?
danifunker said:
Hi Everyone,
I am trying to code my first android app, which is an app that will copy some files from the app's asset folder to /system/app, adjust permissions and let the user know the process has been finished. I am a systems person, not a programmer, so know all of the details as to what has to get done. I create some scripts in /assets, and have the files I want to copy in /assets as well.
How do I go about programming this? Is this the right method I'm looking at doing?
Click to expand...
Click to collapse
Can I have the files? I'll try to do this for you
Sent from my Galaxy Nexus using Tapatalk
Better to help him instead of doing it for him, that way he learns more and gets his hands dirty. =p
Hehe, thanks for the response guys!
Anyways, tycoon177, thanks for signing up to help me!
I have zipped up everything I have related to the project, it is pretty simple, I just want to copy some files from the progrsm into /system/app, I have created an install and an uninstall script (although I haven't tested them just yet, not sure how I would do that right now) and have placed those scripts in the /assets/scripts folder. The goal is to copy the files into the proper locations, in order for the Kobo Vox to get access to the Android market. I have devised some instructions and posted them in the following forum page ( http://www.mobileread.com/forums/showthread.php?t=160948&page=1 ), but a lot of users seem to be messing up their system (they aren't a technical bunch) so I figured I should try and learn java and build an app for all of this...
Unfortunately this is a little beyond my abilities, but my intro to Java course starts tonight hehe.
Anyways, the project name is called OogleVox, it won't need to be going onto the Android Market, and will probabably just be an apk download from one site or another.
The link to the source code is here:
http://www.multiupload.com/ASI47S2BM4
Thanks again for your help!
danifunker said:
Hehe, thanks for the response guys!
Anyways, tycoon177, thanks for signing up to help me!
I have zipped up everything I have related to the project, it is pretty simple, I just want to copy some files from the progrsm into /system/app, I have created an install and an uninstall script (although I haven't tested them just yet, not sure how I would do that right now) and have placed those scripts in the /assets/scripts folder. The goal is to copy the files into the proper locations, in order for the Kobo Vox to get access to the Android market. I have devised some instructions and posted them in the following forum page ( http://www.mobileread.com/forums/showthread.php?t=160948&page=1 ), but a lot of users seem to be messing up their system (they aren't a technical bunch) so I figured I should try and learn java and build an app for all of this...
Unfortunately this is a little beyond my abilities, but my intro to Java course starts tonight hehe.
Anyways, the project name is called OogleVox, it won't need to be going onto the Android Market, and will probabably just be an apk download from one site or another.
The link to the source code is here:
http://www.multiupload.com/ASI47S2BM4
Thanks again for your help!
Click to expand...
Click to collapse
I don't know what Kobo Vox is, but for android, in general, the /system partition is read only, and on most devices the MMC or eMMC is locked so that it can't even be remounted read/write. Also, any user app won't be able to gain the required permissions to write to /system/app even if the partition was unlocked and mounted read/write. If you are rooted and security allows you write access to the MMC/eMMC, then you'd need su to gain the required permissions from the OS.
Gene Poole said:
I don't know what Kobo Vox is, but for android, in general, the /system partition is read only, and on most devices the MMC or eMMC is locked so that it can't even be remounted read/write. Also, any user app won't be able to gain the required permissions to write to /system/app even if the partition was unlocked and mounted read/write. If you are rooted and security allows you write access to the MMC/eMMC, then you'd need su to gain the required permissions from the OS.
Click to expand...
Click to collapse
Thanks Gene Poole, I know this app will require root permissions, which will require a run as su. That's going to be a requirement for the app
Questions or Problems Should Not Be Posted in the Development Forum
Please Post in the Correct Forums
Moving to Q&A
Sorry, I did not figure this out..
Sent from my Galaxy Nexus using Tapatalk
tycoon177 said:
Sorry, I did not figure this out..
Sent from my Galaxy Nexus using Tapatalk
Click to expand...
Click to collapse
Thanks for trying! I'm taking a Java course at school now, maybe I'll be able to figure this one out in due time.
If you want to write app before learning java you could use basic4android. You could use its phone library to execute the commands direct and as you can also issue adb commands etc with it you could also have your app more interactive whereby it could check for things you know cause problems and react accordingly.
The site is basic4ppc.com I think, it would allow you to quickly and easily code an app and as with eclipse and other ide's it produces native standalone apk files signed and ready for use.
Dave
Sent from my LG P920 using Tapatalk

Storage and File System After Update

I've read a number of forums and such concerning the way this update changes the file system, creating "legacy" and "0" folders and how that may be related to Other category in my Storage settings, which shows over 18 GB used by something I haven't determined.
However, I'm just a simple mechanical engineer and don't really understand what I'm reading regarding this topic. Would it be possible for someone to explain if in more simple terms?
Sent from my HTC One using xda app-developers app
This has actually been a change in Android itself since 4.2, which included as one of its updates the ability to set up multiple user logins that share the same device. The file structure was rearranged to reflect that change, and the "0" folder represents the main admin user. As for the bloated SD card, I think it's due to some data repetition and needs a full wipe to correct the problem, if I'm not mistaken.
Tremendo Slap said:
This has actually been a change in Android itself since 4.2, which included as one of its updates the ability to set up multiple user logins that share the same device. The file structure was rearranged to reflect that change, and the "0" folder represents the main admin user. As for the bloated SD card, I think it's due to some data repetition and needs a full wipe to correct the problem, if I'm not mistaken.
Click to expand...
Click to collapse
I don't have access to a command prompt on my phone, but I suspect that the legacy and /0 directories are not duplicates. One of the two is what is called a soft link, where the file is listed as in that directory but actually resides somewhere else. When I create a new photo, it shows up in both directory structures.

[Q] ...storage/emulated/0, Data/0, mnt/sdcard, etc

...storage/emulated/0
...storage/sdcard0
...mnt/sdcard
...date/media/0
...sdcard
There are other threads about these. I've read them. But I am not asking the same questions about it. From my vague understanding, they are virtual partitions that points to the same (non-duplicated) directory. Why? The answer is beyond my understanding and probably way over my head. But
But the question I'm asking is: Can I treat it like a real internal SD storage? (my last phone was a Sprint Moto Photon, which has dedicated internal SD partition) Do these virtual directories remain after a wipe and flash? Or are they wiped and re-created after a flash. It comes down to: Is it safe to keep backups(ROM ToolboxPro & TitaniumPro), media, and other permanent stuff at this location while I flash ROMs?
I believe that two of those are valid paths, the others are symbolic links (you can tell within ES File Explorer, as you'll see a little arrow in the bottom left corner of the folder icon).
The valid paths can be read from ADB, while the others cannot.
Yes, you can imagine these as virtual partitions if you like, as they are discrete pathways that differ from the other partitions.
As long as you keep items in the root/sdcard folder, they should be there after you wipe and flash.
Sent from my Nexus 7 using Xparent BlueTapatalk 2
Thank you my friend.

[Q] AppArmor rights to read from SD Card

Hello, I am developing an app for offline navigation, the development goes steady and a more or less usable app is ready now. I am just struggling with one thing, I now put the map files in <SD_CARD>/Pictures/osmscout and add picture_files_read to the apparmor file. Of course Pictures is not the right location for maps, but how can I give my app rights for another location on the sd card, like <SD_CARD>/Maps/osmscout or something?
The description of picture_files_read in the ubuntu-sdk apparmor dialog says that this apparmor profile should give read access to /media/*/r (at least temporarily) however it doesn't actually give me permissions to any other location than Pictures.
Any ideas?
Thanks
Ubuntu prevents file system access to any other location than your own data, cache and config directories by design. That decision was made to improve the security of the system.
However, as noted, you do have write access to three directories:
Code:
~/.local/share/package.name (for user data)
~/.cache/package.name (for caching)
~/.config/package.name (for config files)
The directory which would be best for your purposes would probably be the cache directory.
That one isn't located on the sd card but it's the only option you have.
Sent from my awesome Ubuntu Touch device using the Forum Browser app
Well, the cache directory is just in the home directory and probably not big enough. I don't even need write access, just read access for now, as the user is putting the files there manually.
Until I have found a workaround, I am putting the files in Pictures.
At least for the Aquaris, the home partition is too small to store any serious map files, they can easily be a few GB.
nikwen said:
Ubuntu prevents file system access to any other location than your own data, cache and config directories by design. That decision was made to improve the security of the system.
However, as noted, you do have write access to three directories:
Code:
~/.local/share/package.name (for user data)
~/.cache/package.name (for caching)
~/.config/package.name (for config files)
The directory which would be best for your purposes would probably be the cache directory.
That one isn't located on the sd card but it's the only option you have.
Sent from my awesome Ubuntu Touch device using the Forum Browser app
Click to expand...
Click to collapse
Sadly, I don't see many options here.
The only one which I can think of is the following: Ask your users to download the terminal app and copy over a command which either creates a (persistent) symbolic link from /home to their data directories on their sd cards or mounts the said folders in their home directories (the latter wouldn't be persistent after a reboot).
You still have to check out if that works but I'm confident that at least the mount scenario works.
Otherwise, I believe this would be a good question for the Ubuntu Phone mailing list where the OS developers hang out, too: http://launchpad.net/~ubuntu-phone.
Sent from my awesome Ubuntu Touch device using the Forum Browser app

microSD card access in Android Apps

Hello,
I'm considering purchasing the Samsung Chromebook Plus when it gets released and I don't to get anything wrong considering I live in the EU and will be importing it from the USA shall I decide to make this purchase. What finally pushed to towards purchasing a Chromebook is Android Apps and Play Store availability. However, as I understand, the only folder Chrome OS and Android actually have in common and can both access in the Downloads folder, which means no access to microSD card. In any case, if a purchase a chromebook, I plan to put it in Developer Mode, for multiple reasons among which is the ability to install a APK. My question is : is it possible, when in Dev Mode, to create a symlink (the way you create a symlink in *NIX systems) in the Downloads folder that leads to the microSD card and access the external storage from Android Apps (one of the main reason I want to do that is sync Dropbox and OneDrive files to the microSD) ? I thought I read it was possible sometimes in late 2016 but I can't seem to find it anymore.
Thanks in advance for your help.
There's a way to mount it as read only: http://nolirium.blogspot.com/2016/12/making-sd-card-content-accessible-to.html
Or if you get root within the android application it may work: http://nolirium.blogspot.com/2016/12/android-on-chrome-os-rooting-shell.html
Wow thanks! That's not even very difficult (at least for read access). Only problem is when suspending. Maybe that could be solved by automating the process!
Do you know if it is possible to manually mount ext4 sd cards in chrome os ? I just thought you might be unable to write due to folder ownership but maybe setting it manually would help.
Do you what the unix username of Android user is ?
EDIT: there is so little information about it that I believe I'll have to try it out myself

Categories

Resources