Re: [Haskell-cafe] fcntl locks, executeFile and threaded runtime

Question about the syscall trace -- in the second, threaded version,

[pid 11612] fcntl(7, F_SETLK, {type=F_WRLCK, whence=SEEK_SET, start=0, len=0}) = 0 ... [pid 11612] +++ exited with 0 +++

?? In the not threaded version, I don't see the child process exit - and wasn't expecting to, since it's supposed to have exec'd to /usr/bin/sleep. Donn ------------

ghc -rtsopts --make test.hs; strace -f -e trace=fork,fcntl,dup,dup2,close -e signal=\!SIGVTALRM ./test >/dev/null close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 Process 11591 attached [pid 11591] fcntl(3, F_SETLK, {type=F_WRLCK, whence=SEEK_SET, start=0, len=0}) = 0 [pid 11591] close(4) = 0 [pid 11591] close(4) = 0 [pid 11591] close(4) = 0 [pid 11590] fcntl(3, F_SETLK, {type=F_WRLCK, whence=SEEK_SET, start=0, len=0}) = -1 EAGAIN (Resource temporarily unavailable) test: setLock: resource exhausted (Resource temporarily unavailable) [pid 11590] +++ exited with 1 +++ close(1) = 0 close(2) = 0 +++ exited with 0 +++

ghc -threaded -rtsopts --make test.hs; strace -f -e trace=fork,fcntl,dup,dup2,close -e signal=\!SIGVTALRM ./tes[23/96461] ll Linking test ... close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 close(3) = 0 fcntl(3, F_SETFD, FD_CLOEXEC) = 0 fcntl(5, F_GETFL) = 0x1 (flags O_WRONLY) fcntl(5, F_SETFL, O_WRONLY|O_NONBLOCK) = 0 fcntl(4, F_SETFD, FD_CLOEXEC) = 0 fcntl(5, F_SETFD, FD_CLOEXEC) = 0 Process 11610 attached [pid 11609] fcntl(6, F_GETFL) = 0x2 (flags O_RDWR) [pid 11609] fcntl(6, F_SETFL, O_RDWR|O_NONBLOCK) = 0 [pid 11609] fcntl(6, F_SETFD, FD_CLOEXEC) = 0 Process 11611 attached Process 11612 attached [pid 11612] close(3) = 0 [pid 11612] close(4) = 0 [pid 11612] close(5) = 0 [pid 11612] close(6) = 0 [pid 11612] fcntl(3, F_SETFD, FD_CLOEXEC) = 0 [pid 11612] fcntl(5, F_GETFL) = 0x1 (flags O_WRONLY) [pid 11612] fcntl(5, F_SETFL, O_WRONLY|O_NONBLOCK) = 0 [pid 11612] fcntl(4, F_SETFD, FD_CLOEXEC) = 0 [pid 11612] fcntl(5, F_SETFD, FD_CLOEXEC) = 0 Process 11613 attached [pid 11612] fcntl(6, F_GETFL) = 0x2 (flags O_RDWR) [pid 11612] fcntl(6, F_SETFL, O_RDWR|O_NONBLOCK) = 0 [pid 11612] fcntl(6, F_SETFD, FD_CLOEXEC) = 0 [pid 11612] fcntl(7, F_SETLK, {type=F_WRLCK, whence=SEEK_SET, start=0, len=0}) = 0 [pid 11613] +++ exited with 0 +++ [pid 11612] close(3) = 0 [pid 11612] close(3) = 0 [pid 11612] close(3) = 0 [pid 11609] fcntl(7, F_SETLK, {type=F_WRLCK, whence=SEEK_SET, start=0, len=0}) = 0 [pid 11612] close(1) = 0 [pid 11612] close(2) = 0 [pid 11612] +++ exited with 0 +++ [pid 11609] --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=11612, si_status=0, si_utime=0, si_stime=0} --- [pid 11610] close(3) = 0 [pid 11610] close(4) = 0 [pid 11610] close(5) = 0 [pid 11610] close(6) = 0 [pid 11610] +++ exited with 0 +++ [pid 11611] +++ exited with 0 +++ +++ exited with 0 +++

At Fri, 25 Oct 2013 13:28:23 -0400, Brandon Allbery wrote:

...

[1 ] [1.1 ]

[1.2 ] On Fri, Oct 25, 2013 at 1:20 PM, Donn Cave wrote:

> > On Fri, Oct 25, 2013 at 11:52 AM, Donn Cave wrote: > >> But I don't see how executeFile could >> make any difference, in that scenario. > > Look for fcntl(fd, FD_CLOEXEC, 1) calls?

Oh, that would be heinous!

It would be because I got that completely wrong. fcntl(fd, F_SETFD, FD_CLOEXEC). sigh.

-- brandon s allbery kf8nh                sine nomine associates allbery.b@gmail.com                 Âballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad    Âhttp://sinenomine.net

[2 ] _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe