Bug#910923: $PLATFORM is no longer expanded.

[Aurelien Jarno <aurelien@aurel32.net>]

On 2018-10-15 00:49, Roman Lebedev wrote:
> On Sun, Oct 14, 2018 at 10:51 PM Aurelien Jarno <aurelien@aurel32.net> wrote:
> >
> > control: severity -1 normal
> > control: retitle -1 libc6: broken support for curly braces DST
> >
> > On 2018-10-13 16:13, Roman Lebedev wrote:
> > > Source: glibc
> > > Version: 2.27-6
> > > Severity: important
> > >
> > > Reproduction:
> > > $ strace -ELD_PRELOAD='/sss/${PLATFORM}/dddd'  -s300  /bin/cat
> > > execve("/bin/cat", ["/bin/cat"], 0x55ddc6b820f0 /* 64 vars */) = 0
> > > brk(NULL)                               = 0x56046d9c1000
> > > access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
> > > readlink("/proc/self/exe", "/bin/cat", 4096) = 8
> > > openat(AT_FDCWD, "/sss/x86_64/dddd", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
> Hm actually wait, i think i'm confused here.
> Both the ${PLATFORM} and $PLATFORM seem to expand just fine.
> 
> $ strace -ELD_PRELOAD='/sss/${PLATFORM}/dddd'  -s300  /bin/cat | grep PLATFORM
> ...
> openat(AT_FDCWD, "/sss/x86_64/dddd", O_RDONLY|O_CLOEXEC) = -1 ENOENT
> (No such file or directory)
> writev(2, [{iov_base="ERROR: ld.so: object '", iov_len=22},
> {iov_base="/sss/${PLATFORM}/dddd", iov_len=21}, {iov_base="' from ",
> iov_len=7}, {iov_base="LD_PRELOAD", iov_len=10}, {iov_base=" cannot be
> preloaded (", iov_len=22}, {iov_base="cannot open shared object file",
> iov_len=30}, {iov_base="): ignored.\n", iov_len=12}], 7ERROR: ld.so:
> object '/sss/${PLATFORM}/dddd' from LD_PRELOAD cannot be preloaded
> (cannot open shared object file): ignored.
> ) = 124
> 
> $ strace -ELD_PRELOAD='/sss/$PLATFORM/dddd'  -s300  /bin/cat | grep PLATFORM
> ...
> openat(AT_FDCWD, "/sss/x86_64/dddd", O_RDONLY|O_CLOEXEC) = -1 ENOENT
> (No such file or directory)
> writev(2, [{iov_base="ERROR: ld.so: object '", iov_len=22},
> {iov_base="/sss/$PLATFORM/dddd", iov_len=19}, {iov_base="' from ",
> iov_len=7}, {iov_base="LD_PRELOAD", iov_len=10}, {iov_base=" cannot be
> preloaded (", iov_len=22}, {iov_base="cannot open shared object file",
> io
> v_len=30}, {iov_base="): ignored.\n", iov_len=12}], 7ERROR: ld.so:
> object '/sss/$PLATFORM/dddd' from LD_PRELOAD cannot be preloaded
> (cannot open shared object file): ignored.
> ) = 122
> 
> It clearly expanded PLATFORM to x86_64 in both cases, do you agree?
> 
> So whatever i'm seeing is something else, might be caused by docker.
> 

I agree that both are correctly expanded. I also looked again calmly on
my system, and I confirm that both are expanded. So it looks like there
is no bug there.

Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net