urgent need is when you run sh around a program that intentionally
uses SIGQUIT/SIGINT for asynchronous events, i.e. $EDITOR started from
system(2), like many mailers do. This fixes PR bin/1206 and possibly
bin/4241.
The solution committed has been tested for a large number of possible
cases (see recent discussion on cvs-committers). I completed a make
world, made sure 'make world' is interruptable and used the changed
/bin/sh as a login shell all day, including job control and using
SIGQUIT-catching programs (to write this message :-).
PR: bin/1206
Reviewed by: discussion on cvs-commiters
cast value that was always ignored. Rev.1.9 of trap.c made this
more bogus by returning a semantically different value after calling
siginterrupt(). Avoid these problems by not returning a value.
trap 'echo xxx' 1 2 3 15
read x
is not interrupted by ^C (due to restartable read syscall) and must be
interrupted per POSIX
Worse case:
read -t 5 x
hangs forever after ^C pressed (supposed to timeout after 5 secs)
Fixed by adding siginterrupt(signo, 1) after catch handler installed
2) Do not reinstall sighandler immediately after it is called,
BSD do it for us
'read' command to return an error if the user fails to supply any
input withink a given time period. The behaviour of this option is
similar to that of the like-named option in ksh93.
Reviewed by: joerg
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
while remaining (becoming :) compatible with other popular shells.
Specifically these changes include:
1) Implement 'trap -l' to get a list of valid signals names. This
is useful if you wanted to do something like reset all signal
handlers to there defaults values, in which case something like
this will do the trick.
trap `trap -l`
2) Reformat the output of 'trap' so it can be saved and later eval'd
to restore the saved settings.
3) Allow the use of signal names as well as signal numbers.
4) Fix trap handling of SIGCHLD so that commands like the following
(albeit, contrived) won't cause sh(1) to recurse ad infinitum.
trap uname 0 20
5) Make variables static that are used only in trap.c.
6) Minor 'style(9) police' mods.
now handles the getpwd() init problem the same way as bash
and ksh do. Also while I was in here, I cleaned up the format
a little, removed some unnnecessary #if SYMLINKS cruft, and
changed the pwd builtin to use getcwd(3) as Joerg suggested.
