New version is broken!

[alkino]

Hi!
When I want to start proot on my usual arm-rootfs it crashed:

proot -q qemu-arm ./rootfs/
Registering `cpu' which already exists
And it doesn't proot in the directory.

But it can be funnier:

proot -Q qemu-arm ./something-wrong
Segmentation fault

GDB

60 status = snprintf(result, PATH_MAX, "/proc/%d", tracee->pid);
(gdb) bt
#0 readlink_proc (tracee=tracee@entry=0x0, result=result@entry=0x7fffffff6310 "/proc/self",

base=base@entry=0x6180d8 "/proc", component=<optimized out>, component@entry=0x7fffffff6210 "self", 
comparison=PATHS_ARE_EQUAL) at ./path/proc.c:60

#1 0x00000000004061b1 in canonicalize (tracee=tracee@entry=0x0,

fake_path=fake_path@entry=0x7fffffff84f0 "/proc/self/mounts", deref_final=deref_final@entry=true, 
result=result@entry=0x6180d8 "/proc", nb_readlink=nb_readlink@entry=1) at ./path/canon.c:166

#2 0x000000000040623d in canonicalize (tracee=tracee@entry=0x0,

fake_path=fake_path@entry=0x7fffffffa6d0 "/etc/mtab", deref_final=deref_final@entry=true, 
result=result@entry=0x6180d8 "/proc", nb_readlink=1, nb_readlink@entry=0) at ./path/canon.c:195

#3 0x0000000000405c0a in init_bindings () at ./path/binding.c:571
#4 0x000000000040681a in init_module_path () at ./path/path.c:202
#5 0x0000000000401958 in main (argc=4, argv=0x7fffffffe8d8) at ./cli.c:449

(gdb) p tracee
0x0

[cedric-vincent]

Hi Alkino,

Thanks for this bug report, however I'm not able to reproduce this problem. Please, could you specify:

• the version of PRoot (I suppose this is v2.0)
• the version of QEMU
• the host distro
• the guest distro in rootfs
• the type of "./something-wrong" (file, directory, pipe, ...)

Thanks in advance,
Cédric.

[cedric-vincent]

OK, I'm able to reproduce the problem:

ln -s  /proc/self/mounts mtab
./proot -b mtab
Segmentation fault

Thanks.

[cedric-vincent]

Please, could you check the patch I pushed in the "next" branch fixes this problem?

Thanks in advance.
Cédric.

[cedric-vincent]

The following error is due to another problem in PRoot v2.0 when using QEMU v1.1:

Registering `cpu' which already exists

I'm investigating.

[cedric-vincent]

Actually, the problem is reproducible without PRoot:

/lib64/ld-linux-x86-64.so.2 arm-linux-user/qemu-arm
Registering `arm-cpu' which already exists
Aborted

We just have to ask PRoot to not use the dynamic linker as a loader:

env PROOT_IGNORE_ELF_INTERPRETER=1 proot -q qemu-arm ./rootfs/

I will submit a patch for PRoot today.

[cedric-vincent]

Hi Alkino,

Please, could you confirm PRoot v2.0.1 solves these problems?

[alkino]

proot -Q qemu-arm ./media/rootfs/
proot warning: can't create the guest path (binding) "/proc/self/mounts": you can still access it directly, without seeing it though

I got this. Is it normal?

[cedric-vincent]

Well, this is not unexpected. I could confirm that only if you specify what the guest and host distros are.

[alkino]

Both are archlinux.

[cedric-vincent]

In your guest rootfs, "/etc/mtab" points to "/proc/self/mounts" but PRoot fails at creating "/proc/self". However this shouldn't create any trouble.

For information, these kind of warnings will disappear in the next release of PRoot (thanks to a new feature).