[GHC] #7695: Hang when locale-archive and gconv-modules are not there

[GHC]

#7695: Hang when locale-archive and gconv-modules are not there
-------------------------+--------------------------------------------------
Reporter:  hpd           |          Owner:                  
    Type:  bug           |         Status:  new             
Priority:  normal        |      Component:  None            
 Version:  7.6.2         |       Keywords:                  
      Os:  Linux         |   Architecture:  Unknown/Multiple
 Failure:  None/Unknown  |      Blockedby:                  
Blocking:                |        Related:                  
-------------------------+--------------------------------------------------
 Running a (statically) compiled program in an environment where
 /usr/lib/locale or /usr/lib/gconv (or ../lib64/..) are not there, causes
 it to hog the CPU and rapidly allocate memory (this happens for example in
 an empty chroot).

 Steps to reproduce:

 {{{
 echo "main = return ()" > test.hs
 ghc -static -optl-static -optl-pthread -o test test.hs
 chroot `pwd` /test
 }}}

 Strace output:

 {{{
 $ /strace -e trace=file -e signal= /test
 execve("/test", ["/test"], [/* 17 vars */]) = 0
 open("/usr/lib64/locale/locale-archive", O_RDONLY|O_CLOEXEC) = -1 ENOENT
 (No such file or directory)
 open("/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No
 such file or directory)
 open("/usr/lib64/locale/de_DE.UTF-8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1
 ENOENT (No such file or directory)
 open("/usr/lib64/locale/de_DE.utf8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1
 ENOENT (No such file or directory)
 open("/usr/lib64/locale/de_DE/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT
 (No such file or directory)
 open("/usr/lib64/locale/de.UTF-8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1
 ENOENT (No such file or directory)
 open("/usr/lib64/locale/de.utf8/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT
 (No such file or directory)
 open("/usr/lib64/locale/de/LC_CTYPE", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No
 such file or directory)
 open("/usr/lib64/gconv/gconv-modules.cache", O_RDONLY) = -1 ENOENT (No
 such file or directory)
 open("/usr/lib64/gconv/gconv-modules", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No
 such file or directory)
 }}}

 Strace output (with LC_ALL=C):

 {{{
 $ LC_ALL=C strace -e trace=file -e signal= /test
 execve("/test", ["/test"], [/* 18 vars */]) = 0
 open("/usr/lib64/gconv/gconv-modules.cache", O_RDONLY) = -1 ENOENT (No
 such file or directory)
 open("/usr/lib64/gconv/gconv-modules", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No
 such file or directory)
 }}}

 In both cases, there are no further system calls (apart from timer ticks
 and mmap).

 I was also able to reproduce this behavior without a chroot, by replacing
 the paths from strace's output with something nonexistent in the binary
 (manually, with a hex-editor). I didn't try dynamically linked binaries,
 yet.

 One problem ''may'' be, that iconv_open constantly returns -1 if it
 doesn't find the files listed above.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7695>
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