Control: reassign -1 apt 1.3~pre2 Control: affects -1 + apt-listbugs
On Fri, 29 Jul 2016 19:41:28 +0200 Francesco Poli wrote: > Hence, I am suspecting that the misbehavior has something to do with > the way the package manager invokes its hooks... [...] > > I am Cc-ing the APT Development Team: could any of you take a look at > bug #832593, please? > Any ideas on why a hook that traps SIGINT runs into troubles, when it > catches such signal, but does not immediately exit? Hello again, APT Development Team. I prepared an overly simple script that traps SIGINT, asks the user to press [Enter] and then goes on with its own business (simple-trap-sigint.sh, that should be found attached to this message). I believe that trapping SIGINT and using this signal for something other than an immediate exit is a perfectly legitimate use of SIGINT. An already cited document [1] confirms this. [1] https://www.cons.org/cracauer/sigint.html When this script is called by a trivial script executed by bash (calling-script.sh, also attached), everything works as expected, since GNU bash implements the WCE approach (explained in [1]): $ ./calling-script.sh Start Hello! Output 1 Output 2 Output 3 ^CPress [Enter] to continue Output 4 Output 5 Output 6 Output 7 Output 8 Output 9 Output 10 Bye! End Of course, the last part of the output (from "Output 4" onwards) is shown after hitting [Enter], as requested. On the other hand, when the script is executed by APT as a hook, things go wrong somehow: # cat /etc/apt/apt.conf.d/05test DPkg::Pre-Install-Pkgs {"/root/simple-trap-sigint.sh";}; # apt install locales Reading package lists... Done Building dependency tree Reading state information... Done The following additional packages will be installed: libc-l10n The following NEW packages will be installed: libc-l10n locales 0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded. Need to get 0 B/4198 kB of archives. After this operation, 17.1 MB of additional disk space will be used. Do you want to continue? [Y/n] Hello! Output 1 Output 2 Output 3 Output 4 ^CPress [Enter] to continueOutput 5 # Output 6 Output 7 Output 8 Output 9 Output 10 Bye! # After pressing [Ctrl+C], the hook (simple-trap-sigint.sh) shows the expected "Press [Enter] to continue" message, but immediately goes on with its output, without waiting for input from the user. The final prompt is obtained after hitting [Enter]. But apt has already exited, instead of waiting for the hook to exit and checking whether the hook was killed by a SIGINT... What's wrong? Does libapt implement the IUE approach (explained in [1])? If this is the case, then I think that the WCE approach should be implemented instead, at least when executing hooks, since some hooks may use SIGINT for purposes other than an immediate exit. I am consequently reassigning this bug report to apt/1.3~pre2 ... Please fix this issue. Thanks for your time. Bye. -- http://www.inventati.org/frx/ There's not a second to spare! To the laboratory! ..................................................... Francesco Poli . GnuPG key fpr == CA01 1147 9CD2 EFDF FB82 3925 3E1C 27E1 1F69 BFFE
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