LLVM bug WRT temporary files?

[David Chisnall]

This looks like a bug, please file an llvm PR.  The offending code seems to be createUniqueEntity() in lib/Support/Unix/Path.inc, which does... something.  Something weird and convoluted that seems to try to implement mkstemp() / mkdtemp() in an incomprehensible way.

David

On 13 Feb 2014, at 17:33, Marcel Moolenaar <marcel at xcllnt.net> wrote:

> Guys,
> 
> I'm running into a build break that relates to the temporary files
> that LLVM creates:
> 
> svl-junos-j019% cc --version
> FreeBSD clang version 3.3 (tags/RELEASE_33/final 183502) 20130610
> Target: arm--freebsd10.0-gnueabi
> Thread model: posix
> 
> 
> On a build machine /tmp/b is a directory and created by user X.
> I am doing a buildworld on that machine as user Y (Y=marcelm) and
> I don't have permissions in /tmp/b. The build gets to usr.bin/awk
> and it has a source file called b.c
> 
> 
> The build fails with:
> 
> --- b.o ---
> cc  -O -pipe  -DHAS_ISBLANK -I. -I/b/marcelm/buildbot/FreeBSD_arm_arm/build/usr.bin/awk/../../contrib/one-true-awk -DFOPEN_MAX=64 -std=gnu99 -Qunused-arguments  -Wsystem-headers -Werror -Wno-pointer-sign -Wno-empty-body -Wno-string-plus-int -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion -Wno-switch -Wno-switch-enum -Wno-knr-promoted-parameter -Wno-parentheses -c /b/marcelm/buildbot/FreeBSD_arm_arm/build/usr.bin/awk/../../contrib/one-true-awk/b.c
> cc: error: unable to make temporary file: /tmp/b: can't make unique filename: Permission denied
> *** [b.o] Error code 1
> 
> 
> Running truss shows:
> 
> access("/b/marcelm/buildbot/FreeBSD_arm_arm/build/usr.bin/awk/../../contrib/one-true-awk/b.c",0) = 0 (0x0)
> stat("/tmp/b",{ mode=drwxr-xr-x ,inode=235520,size=512,blksize=16384 }) = 0 (0x0)
> open("/dev/random",O_RDONLY,00)			 = 3 (0x3)
> read(3,"\M^S\M^H\^S65S'*\M-T\M-r\^A9\M-K"...,128) = 128 (0x80)
> close(3)					 = 0 (0x0)
> stat("/tmp/b",{ mode=drwxr-xr-x ,inode=235520,size=512,blksize=16384 }) = 0 (0x0)
> open("/tmp/b/B8owDb",O_RDWR|O_CREAT|O_EXCL,0600) ERR#13 'Permission denied'
> 
> 
> Now, if I compile another file, I get:
> 
> access("/b/marcelm/buildbot/FreeBSD_arm_arm/build/usr.bin/awk/../../contrib/one-true-awk/lex.c",0) = 0 (0x0)
> stat("/tmp/lex",0x7fffffffbab0)			 ERR#2 'No such file or directory'
> open("/dev/random",O_RDONLY,00)			 = 3 (0x3)
> read(3,"\^F\r\M-J\M-5Z\M-fK\^E\M-2'\M-1"...,128) = 128 (0x80)
> close(3)					 = 0 (0x0)
> stat("/tmp",{ mode=drwxrwxrwt ,inode=2,size=9728,blksize=16384 }) = 0 (0x0)
> open("/tmp/lex-pDQnPA",O_RDWR|O_CREAT|O_EXCL,0600) = 3 (0x3)
> close(3)					 = 0 (0x0)
> 
> 
> So for some reason when /tmp/<basename> exists and is a directory, then the
> compiler wants to create a temporary file underneath that directory. That
> looks like a bug to me. Do people concur and thus shall I file a PR?
> 
> -- 
> Marcel Moolenaar
> marcel at xcllnt.net
> 
>