Cross-device consistent symlink for internal storage

Question

There are many paths to internal storage:

/sdcard

/storage/sdcard0

/storage/emulated/0

/storage/emulated/legacy

/mnt/sdcard

/data/media/0

Several questions:

Which ones are most consistent (present) across devices?
Which ones are most likely to have Read+Write permissions? Do the symlinks alter this behavior?
Which one is the true storage location, where the rest of the symlinks point to? Does this also vary across devices?

Is there a final objective of yours that would be completed by knowing a consistent cross-device symlink among thousands of devices? — Firelord, Feb 07 '16 at 14:37

score 0 · Answer 1 · edited Apr 13 '17 at 12:18

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To answer all of that, one needs to know all (or at least most) of the devices available. So all I can give is an "educated guess".

Permissions should not be altered by symlinks. And yes, what's there varies across devices, Android versions and even ROMs used.

Find the "real one" using df or mount at the command prompt (either via a terminal app, or using adb shell). Starting with around Android 4.2, a few of your listed locations should be pretty much standard:

/storage/emulated/0
/storage/emulated/legacy

The others, as I wrote, may vary between devices, Android versions and ROMs.

Concerning read/write permissions: All of them have. Question is just: for whom? The average app, or root? This changed a lot between Android versions, especially since Kitkat, and again might be handled differently by device, Android version, and ROM. Before Kitkat, an app just needed the WRITE_EXTERNAL_STORAGE permission. With Kitkat, on most ROMs it was restricted to its own directory in Android/data/, and with Lollipop that changed again.

For a reference, please also see Confused by the many locations of the virtual /sdcard/.

edited Apr 13 '17 at 12:18

Community

1

answered Feb 07 '16 at 12:41

Izzy

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Can you provide a reference for Kitkat being locked down to /data/x? – Aaron Gillion Feb 07 '16 at 12:47
Maybe related: http://developer.android.com/guide/topics/data/data-storage.html – GiantTree Feb 07 '16 at 12:50
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LOL Tons of references if you just do a search on "Kitkat sdcard". That gave a pretty loud cry back then. For an example: Android KitKat Blocks Some Access to Micro SD Cards, KitKat will make your SD Card completely useless. – Izzy Feb 07 '16 at 12:53
I'm planning to change my question so it doesn't duplicate "Confused [..] virtual /sdcard/", I'm also working up an answer based on many test devices from Samsung, LG, Nexus, Acer, etc. I still have to get my hands on some of them yet via a friend of mine. – Aaron Gillion Feb 07 '16 at 12:57
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@AaronGillion: maybe you can initiate a wiki thereafter?! – beeshyams Feb 07 '16 at 14:59
Not sure. Can you refer me to a help page on what it does/how to initiate one/how it works? The list is getting very long, I will post the overall results below but I'm planning to make a page on my website with each device. Not sure if wiki will help here..? – Aaron Gillion Feb 07 '16 at 15:49

Cross-device consistent symlink for internal storage

There are many paths to internal storage:

1 Answers1