Re: [gentoo-musl] realpath() gives wrong result on a chroot musl system

[Lei Zhang]

2016-06-07 6:04 GMT+08:00 Felix Janda <felix.janda@××××××.de>:
> Lei Zhang wrote:
>> Hi,
>>
>> I was trying to run clang (built specifically for musl) on a chroot
>> musl system, and met some strange issue. After some investigation, it
>> turns out the function realpath() is giving me wrong results.
>>
>> I can reproduce the error with the following code snippet:
>>
>> #include <stdio.h>
>> #include <stdlib.h>
>> #include <limits.h>
>>
>> int main(int argc, char** argv) {
>>     const char* path = "/usr/bin/clang"; // suppose this is a valid path
>>     char resolved[PATH_MAX];
>>     char* ret = realpath(path, resolved);
>>
>>     if (ret)
>>         printf("%s\n", ret);
>> }
>>
>> If I build it against musl, it gives correct result on my host, but
>> wrong result on chroot; If I build it against glibc (statically, since
>> there's no glibc on chroot), it gives correct results on both
>> environments. So it looks like musl is to blame on the chroot
>> environment. I haven't yet confirmed if it's a bug.
>>
>> Any thoughts?
>
> With musl, realpath() (and some other things) depend on having a
> mounted /proc.

You're right!

After mounting /proc on the chroot system, the issue is resolved. At
this point I'm really not sure if this is musl's bug. Is it legit to
unconditionally depends on the presence of a mounted /proc?


Lei