Date: Tue, 7 May 2013 14:08:06 -0700 From: Garrett Cooper <yaneurabeya@gmail.com> To: dim@freebsd.org Cc: toolchain@freebsd.org Subject: Re: clang doesn't make temporary files in all instances, causes build races by not using mk*temp(3) in /tmp Message-ID: <CAGHfRMDdB0TSsigizCU-hn9gAdJcq5_o6MeDeckGd3zmjYbmTg@mail.gmail.com> In-Reply-To: <CAGHfRMCnmViGvJadmmmKyE=mAdgWFbX5woPUbGb3mdUVkUbFeQ@mail.gmail.com> References: <CAGHfRMCnmViGvJadmmmKyE=mAdgWFbX5woPUbGb3mdUVkUbFeQ@mail.gmail.com>
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On Tue, May 7, 2013 at 1:58 PM, Garrett Cooper <yaneurabeya@gmail.com> wrote:
> Hi Dimitriy,
> I ran into the following error when trying to execute make
> tinderbox with FreeBSD svn head with ATF changes I'm going to push to
> benno@:
>
> cc -O -pipe -DHAVE_CONFIG_H
> -I/scratch/freebsd/head-svn/gnu/lib/libgomp -I.
> -I/scratch/freebsd/head-svn/gnu/lib/libgomp/../../../contrib/gcclibs/libgomp
> -I/scratch/freebsd/head-svn/gnu/lib/libgomp/../../../contrib/gcclibs/libgomp/config/posix
> -std=gnu99 -Qunused-arguments -c
> /scratch/freebsd/head-svn/gnu/lib/libgomp/../../../contrib/gcclibs/libgomp/config/posix/bar.c
> -o bar.o
> cc: error: unable to make temporary file: /tmp/bar: can't make unique
> filename: Permission denied
> *** [bar.o] Error code 1
>
> Did some poking around in the clang source and it looks like it's
> doing some less than intelligent things when generating "temporary"
> paths (from contrib/llvm/tools/clang/lib/Driver/Driver.cpp ):
>
> 1598 std::string Driver::GetTemporaryPath(StringRef Prefix, const char *Suffix)
> 1599 const {
> 1600 // FIXME: This is lame; sys::Path should provide this function
> (in particular,
> 1601 // it should know how to find the temporary files dir).
> 1602 std::string Error;
> 1603 const char *TmpDir = ::getenv("TMPDIR");
> 1604 if (!TmpDir)
> 1605 TmpDir = ::getenv("TEMP");
> 1606 if (!TmpDir)
> 1607 TmpDir = ::getenv("TMP");
> 1608 if (!TmpDir)
> 1609 TmpDir = "/tmp";
> 1610 llvm::sys::Path P(TmpDir);
> 1611 P.appendComponent(Prefix);
> 1612 if (P.makeUnique(false, &Error)) {
> 1613 Diag(clang::diag::err_unable_to_make_temp) << Error;
> 1614 return "";
> 1615 }
> 1616
> 1617 // FIXME: Grumble, makeUnique sometimes leaves the file around!? PR3837.
> 1618 P.eraseFromDisk(false, 0);
> 1619
> 1620 if (Suffix)
> 1621 P.appendSuffix(Suffix);
> 1622 return P.str();
>
> This logic (line 1612) is racy and incorrect.
> This _needs_ to be fixed in clang to properly prefix and rename to
> the target path in the filesystem where the compilation is being done
> in order to avoid races with partial compilations, etc.
And I was pointed to these awesome bug reports by someone internal to
Isilon (thanks Anton!):
- http://lists.cs.uiuc.edu/pipermail/llvmbugs/2012-August/024524.html
- http://trac.macports.org/ticket/37834
It looks like the clang folks haven't fixed this issue yet. Arg..
Thanks,
-Garrett
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