[Toybox] Android O: XARGS - bad system call

[darken]

Created an issue ticket for this on the Android O tracker:
https://issuetracker.google.com/issues/37369410

You could try disabling seccomp in Zygote:
>
https://android.googlesource.com/platform/frameworks/base/+
> /o-preview/core/java/com/android/internal/os/ZygoteInit.java#696


I would have to compile my own Pixel Android O ROM for that though right?

~Matthias

2017-04-15 0:02 GMT+02:00 Steve Muckle <smuckle at google.com>:

> Hi Matthias,
>
> On Thu, Apr 13, 2017 at 2:13 PM, darken <darken at darken.eu> wrote:
>
>> I'm not sure how to use strace, how do I get a strace binary into the
>> Android O image?
>>
>> Can't reproduce it on the X86 Android O emulator image.
>> But can reproduce it on my Pixel running Android O.
>> Tried the latest toybox build too but it's not the build, and when
>> running it as shell user (adb) it works:
>>
>> > sailfish:/data/local/tmp $ ./toybox_new find '/data/local/tmp'
>> -maxdepth 0  -print0 | ./toybox_new xargs -0 echo
>> > /data/local/tmp
>> > sailfish:/data/local/tmp $ ./toybox_old find '/data/local/tmp'
>> -maxdepth 0  -print0 | ./toybox_old xargs -0 echo
>> > /data/local/tmp
>> > sailfish:/data/local/tmp $ ./toybox_new --version
>> > toybox 0.7.3-37-g04940678c81a
>> > sailfish:/data/local/tmp $ ./toybox_old --version
>> > toybox 0.7.2-37-g109a28b8a749
>>
>> So it works as shell user, but not as app user.
>> But it also works if the app runs the native toybox from /system.
>> Is this some kind of SELinux issue?
>> Preventing xargs from forking processes or something like that?
>>
>> Why would it work on the emulator though...
>>
>
> This sounds like it may be seccomp, a Linux kernel facility for
> restricting the set of system calls a process may make. It is enforced at
> the zygote level so would affect attempts from apps but presumably not the
> shell. It is configured with the list of system calls in bionic
> (SYSCALLS.TXT) as well as a whitelist (SECCOMP_WHITELIST.TXT):
>
> https://android.googlesource.com/platform/bionic/+/o-preview/libc/
>
> These lists are architecture specific. This is where seccomp was enforced
> at the zygote level:
>
> https://android.googlesource.com/platform/system/core/+/
> c4af05f8a3d67b9a4288a2b37c7fc16755497f6b
>
> You could try disabling seccomp in Zygote:
> https://android.googlesource.com/platform/frameworks/base/+
> /o-preview/core/java/com/android/internal/os/ZygoteInit.java#696
>
> cheers,
> Steve
>
>
>
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