On Fri, Dec 11, 2015 at 2:40 AM, Yoriyuki Yamagata < yoriyuki.yamag...@aist.go.jp> wrote:
> Dear list, > > I found that bash tries to close the same fd twice, consecutively. I’m > using Mac OS X Yosemite, and bash is the newest available (bash-master from > http://tiswww.case.edu/php/chet/bash/bashtop.html yesterday). > > To reproduce the phenomenon, just run this shell script. > > — begin --- > #!/Users/XXXX/bin/bash > > set -- `cat "testfile" | sed '/^\#/d’` > — end --- > Name it testscript > > testfile is the empty file. > > Then, run druss > > $ sudo dtruss -fa sudo -u XXXX ./testscript > > The part of output: > > 96765/0x20858e: 173615 173171 173168 fork() = 96766 0 > 96766/0x208590: 74: 0: 0 fork() = 0 0 > 96766/0x208590: 75 5 0 thread_selfid(0x0, 0x0, 0x0) > = 2131344 0 > 96766/0x208590: 77 3 0 > bsdthread_register(0x7FFF95D0E3E0, 0x7FFF95D0E3D0, 0x2000) = > -1 Err#22 > 96765/0x20858e: 173714 4 0 sigprocmask(0x3, 0x7FFF59BFD7A0, > 0x0) = 0x0 0 > 96765/0x20858e: 173717 3 1 close(0x4) = 0 0 > 96765/0x20858e: 173739 1 0 close(0x4) = -1 Err#9 > > I do not know it is an important problem, but closing the same file > descriptor twice could be fishy. > > Or maybe I missed something? > > Best, > — > Yoriyuki Yamagata > National Institute of Advanced Science and Technology (AIST), Senior > Researcher > The same happens on Fedora Linux 22. Linux it-johnmckown-linux 4.2.6-201.fc22.x86_64 #1 SMP Tue Nov 24 18:42:39 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux bash --version GNU bash, version 4.3.42(1)-release (x86_64-redhat-linux-gnu) Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html > This is free software; you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/\~}" <trace output> ... pipe([3, 4]) = 0 rt_sigprocmask(SIG_BLOCK, [INT CHLD], [CHLD], 8) = 0 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7f31c859a9d0) = 17257 rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0 close(4) = 0 close(4) = -1 EBADF (Bad file descriptor) rt_sigprocmask(SIG_BLOCK, [INT CHLD], [CHLD], 8) = 0 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7f31c859a9d0) = 17258 rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0 close(3) = 0 rt_sigprocmask(SIG_BLOCK, [CHLD], [CHLD], 8) = 0 rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0 rt_sigprocmask(SIG_BLOCK, [CHLD], [CHLD], 8) = 0 rt_sigaction(SIGINT, {0x556792b10290, [], SA_RESTORER, 0x7f31c7c26a50}, {0x556792b2acb0, [], SA_RESTORER, 0x7f31c7c26a50}, 8) = 0 wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 17257 wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 17258 rt_sigaction(SIGINT, {0x556792b2acb0, [], SA_RESTORER, 0x7f31c7c26a50}, {0x556792b10290, [], SA_RESTORER, 0x7f31c7c26a50}, 8) = 0 rt_sigprocmask(SIG_SETMASK, [CHLD], NULL, 8) = 0 close(3) = -1 EBADF (Bad file descriptor) rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=17257, si_uid=1009, si_status=0, si_utime=0, si_stime=0} --- wait4(-1, 0x7ffd3e7b4790, WNOHANG, NULL) = -1 ECHILD (No child processes) rt_sigreturn({mask=[]}) = 0 exit_group(0) = ? +++ exited with 0 +++ </trace> -- Schrodinger's backup: The condition of any backup is unknown until a restore is attempted. Yoda of Borg, we are. Futile, resistance is, yes. Assimilated, you will be. He's about as useful as a wax frying pan. 10 to the 12th power microphones = 1 Megaphone Maranatha! <>< John McKown
