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* jobs: Fix waitcmd busy loopHerbert Xu2020-07-08
| | | | | | | | | | | | We need to clear gotsigchld in waitproc because it is used as a loop conditional for the waitcmd case. Without it waitcmd may busy loop after a SIGCHLD. This patch also changes gotsigchld into a volatile sig_atomic_t to prevent compilers from optimising its accesses away. Fixes: 6c691b3e5099 ("jobs: Only clear gotsigchld when waiting...") Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* redir: Clear saved redirections in subshellHerbert Xu2020-04-29
| | | | | | | | | | | | | | | | | | | | | When we enter a subshell we need to drop the saved redirections as otherwise a subsequent unwindredir could produce incorrect results. This patch does this by simply clearing redirlist. While we could actually free the memory underneath for subshells it isn't really worth the trouble for now. In order to ensure that this is done in every place where we enter a subshell, this patch adds a new mkinit hook called forkreset. The calls closescript, clear_traps and reset_handler are also added to the forkreset hook. This fixes a bug where the first two functions weren't called if we enter a subshell without forking. Reported-by: Harald van Dijk <harald@gigawatt.nl> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* eval: Add vfork supportHerbert Xu2018-05-28
| | | | | | This patch adds basic vfork support for the case of a simple command. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* trap: Globally rename pendingsigs to pending_sigDenys Vlasenko2018-03-10
| | | | | | | | | | | | This variable does not contain "sigs" (plural). It contains either 0 or (one) signal number of a pending signal. For someone unfamiliar with this code, "pendingsigs" name is confusing - it hints at being an array or bit mask of pending singnals. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> CC: dash@vger.kernel.org Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* [EVAL] Fixed trap/return regression due to SKIPEVAL removalHerbert Xu2010-11-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On Wed, Aug 11, 2010 at 08:06:16AM +0000, Guido Berhoerster wrote: > > with the latest git version of dash trap actions are not > evaluated in the context of a function. > > The following script demonstrates the bug: > ----8<---- > read_timeout () { > saved_traps="$(trap)" > trap 'printf "timed out\n"; eval "${saved_traps}"; return' TERM > ( sleep $1; kill -TERM $$ ) >/dev/null 2>&1 & > timer_pid=$! > read $2 > kill $timer_pid 2>/dev/null > } > > read_timeout 5 value > printf "read \"%s\"\n" "${value:=default}" > > ---->8---- > The return statement in the trap inside the read_timeout function > does not return from the function but rather exits the script. > > With dash 0.5.5.1 it works as expected. This bug was caused by the SKIPEVAL removal. When the SKIPEVAL hack was added to improve set -e support in traps, dotrap was changed to return whether set -e was detected. After the removal of SKIPEVAL, set -e is now handled through exraise. However, dotrap still returned a value which is now incorrectly used to trigger an exraise. This patch removes the vestigial link between dotrap and exraise. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* [JOBS] Fix wait regression where it does not wait for all jobsHerbert Xu2010-05-27
| | | | | | | | | | | The sigsuspend patch broke wait by making it return after just one job has completed. This is because we rely on pendingsigs to signal work and never clear it until waitcmd finishes. This patch adds a separate gotsigchld for this purpose so we can clear it before we start waiting. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* [EVAL] Force fork if any trap is set, not just on EXITJilles Tjoelker2010-05-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | In some cases the shell executes a subshell or an external command in the current process. This is not done if a trap on EXIT has been set, so that that trap can execute after the subshell or external command has finished. Extend that check to all traps. (A trap is "set" if a non-empty command string has been attached to it.) Improve encapsulation by exporting an accessor function for this and making the trap array static again. This is much like FreeBSD SVN r194127, enhanced to apply to subshells also (see FreeBSD SVN r194774). Example: dash -c '{ trap "echo moo" TERM; sleep 3; }& sleep 1; kill $!;wait' This should print "moo" after 3 seconds. Example: dash -c '{ trap "echo moo" TERM; (sleep 3) }& sleep 1; kill $!;wait' The same. Example: dash -c '{ trap "echo moo" TERM; sleep 3; :; }& sleep 1; kill $!;wait' This works correctly even without this patch. Signed-off-by: Jilles Tjoelker <jilles@stack.nl> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* [SIGNAL] Remove EXSIGHerbert Xu2009-02-22
| | | | | | Now that waitcmd no longer uses EXSIG we can remove it. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* [JOBS] Fix dowait signal raceHerbert Xu2009-02-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This test program by Alexey Gladkov can cause dash to enter an infinite loop in waitcmd. #!/bin/dash trap "echo TRAP" USR1 stub() { echo ">>> STUB $1" >&2 sleep $1 echo "<<< STUB $1" >&2 kill -USR1 $$ } stub 3 & stub 2 & until { echo "###"; wait; } do echo "*** $?" done The problem is that if we get a signal after the wait3 system call has returned but before we get to INTON in dowait, then we can jump back up to the top and lose the exit status. So if we then wait for the job that has just exited, then it'll stay there forever. I made the original change that caused this bug to fix pretty much the same bug but in the opposite direction. That is, if we get a signal after we enter wait3 but before we hit the kernel then it too can cause the wait to go on forever (assuming the child doesn't exit). In fact this is pretty much exactly the scenario that you'll find in glibc's documentation on pause(). The solution is given there too, in the form of sigsuspend, which is the only way to do the check and wait atomically. So this patch fixes Alexey's race without reintroducing the old bug by converting the blocking wait3 to a sigsuspend. In order to do this we need to set a signal handler for SIGCHLD, so the code has been modified to always do that. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* Copyright/licence updates and remove all traces of sys/cdefs.hHerbert Xu2005-10-29
| | | | | | | | | | | This change updates the BSD licence to the three-clause version since NetBSD has already done so. This makes dash GPL-compatible. It also adds Christos Zoulas (NetBSD ash maintainer) to the COPYING file. I've added "copyright by Herbert Xu" to most files. Finally all CVS IDs and inclusion of sys/cdefs.h have been removed. The latter is needed for support of klibc.
* Added eflag fixes for trap and minusc.herbert2005-09-26
| | | | | | Let evaltree handle traps from cmdloop. Reset evalskip after minusc is executed. Stop executing traps once SKIPEVAL is seen.
* Initial import.Herbert Xu2005-09-26