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Better interactive SIGINT handling (when a trap is set), and other 

cleanups to the trap code.   No longer silently ignore attempts to
do anything other than set SIGKILL or SIGSTOP to the default ('-")
state.   Don't include those in trap or trap -p output (the former
because they cannot be other than in default state, so simply aren't
included, the latter because it is pointless) but do list them
when requested with trap -p SIG.

Interactive mode SIGINT traps are now run ASAP, rather than after
a command has been entered (so the sequence ^C \n is no longer needed
to generate one).   Further, when trapped, in interactive mode,
while waiting for a user command, a SIGINT acts (aside from the
trap being run) just like when not trapped, aborts the command being
entered (rather than leaving it, which it did when libedit was in use)
prints a new prompt, and starts again (which is what should happen.)

Traps other than SIGINT (which has always been handled special in
interactive mode) are unaffected by this change, as are SIGINT traps
in non-interactive shells.    Or that is the intent anyway.

Fix an in_dotrap ref count bug (was never being decremented... that
was inserted in a place never executed) (relatively harmless) and
add/improve some trap/signal related DEBUG mode tracing.
This commit is contained in:
kre 2019-04-25 03:54:10 +00:00
parent f14381d610
commit e904ec4095
1 changed files with 72 additions and 12 deletions
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84
bin/sh/trap.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: trap.c,v 1.51 2019/01/18 06:28:09 kre Exp $ */
/* $NetBSD: trap.c,v 1.52 2019/04/25 03:54:10 kre Exp $ */
/*-
* Copyright (c) 1991, 1993
@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95";
#else
__RCSID("$NetBSD: trap.c,v 1.51 2019/01/18 06:28:09 kre Exp $");
__RCSID("$NetBSD: trap.c,v 1.52 2019/04/25 03:54:10 kre Exp $");
#endif
#endif /* not lint */
@ -46,6 +46,7 @@ __RCSID("$NetBSD: trap.c,v 1.51 2019/01/18 06:28:09 kre Exp $");
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <limits.h>
#include <termios.h>
#undef CEOF /* from <termios.h> but concflicts with sh use */
@ -269,7 +270,9 @@ trapcmd(int argc, char **argv)
CTRACE(DBG_TRAP, ("*all*\n"));
if (printonly) {
for (count = 0, signo = 0 ; signo < NSIG ; signo++)
for (count = 0, signo = 0 ; signo < NSIG ; signo++) {
if (signo == SIGKILL || signo == SIGSTOP)
continue;
if (trap[signo] == NULL) {
if (count == 0)
out1str("trap -- -");
@ -280,10 +283,16 @@ trapcmd(int argc, char **argv)
count = 0;
}
}
}
if (count)
out1str("\n");
}
/*
* We don't need do deal with SIGSTOP or SIGKILL as a
* special case anywhere here, as they cannot be
* ignored or caught - the only possibility is default
*/
for (count = 0, signo = 0 ; signo < NSIG ; signo++)
if (trap[signo] != NULL && trap[signo][0] == '\0') {
if (count == 0)
@ -351,6 +360,11 @@ trapcmd(int argc, char **argv)
ap++;
if (printonly) {
/*
* we allow SIGSTOP and SIGKILL to be obtained
* (action will always be "-") here, if someone
* really wants to get that particular output
*/
out1str("trap -- ");
if (trap[signo] == NULL)
out1str("-");
@ -360,6 +374,27 @@ trapcmd(int argc, char **argv)
continue;
}
if ((signo == SIGKILL || signo == SIGSTOP) && action != NULL) {
#ifndef SMALL
/*
* Don't bother with the error message in a SMALL shell
* just ignore req and return error status silently
* (POSIX says this is an "undefined" operation so
* whatever we do is OK!)
*
* When we do generate an error, make it attempt match
* the user's operand, as best we can reasonably.
*/
outfmt(out2, "trap: '%s%s' cannot be %s\n",
(!is_alpha(ap[-1][0]) ||
strncasecmp(ap[-1], "sig", 3) == 0) ? "" :
is_upper(ap[-1][0]) ? "SIG" : "sig",
ap[-1], *action ? "caught" : "ignored");
#endif
errs = 1;
continue;
}
INTOFF;
if (action)
action = savestr(action);
@ -647,15 +682,23 @@ SHELLPROC {
void
onsig(int signo)
{
CTRACE(DBG_SIG, ("Signal %d, had: pending %d, gotsig[%d]=%d\n",
signo, pendingsigs, signo, gotsig[signo]));
int sav_err = errno;
CTRACE(DBG_SIG, ("onsig(%d), had: pendingsigs %d%s, gotsig[%d]=%d\n",
signo, pendingsigs, intpending ? " (SIGINT-pending)" : "",
signo, gotsig[signo]));
/* This should not be needed.
signal(signo, onsig);
*/
if (signo == SIGINT && (traps_invalid || trap[SIGINT] == NULL)) {
onint();
VTRACE(DBG_SIG, ("onsig(SIGINT), doing it now\n"));
if (suppressint && !in_dotrap)
intpending = 1;
else
onint();
errno = sav_err;
return;
}
@ -666,7 +709,22 @@ onsig(int signo)
signo != SIGCHLD) {
gotsig[signo] = 1;
pendingsigs++;
if (iflag && signo == SIGINT) {
if (!suppressint) {
VTRACE(DBG_SIG,
("onsig: -i gotsig[INT]->%d pendingsigs->%d BANG\n",
gotsig[SIGINT], pendingsigs));
onint();
errno = sav_err;
return;
}
intpending = 1;
}
VTRACE(DBG_SIG, ("onsig: gotsig[%d]->%d pendingsigs->%d%s\n",
signo, gotsig[signo], pendingsigs,
intpending ? " (SIGINT pending)":""));
}
errno = sav_err;
}
@ -684,15 +742,19 @@ dotrap(void)
int savestatus;
struct skipsave saveskip;
in_dotrap++;
CTRACE(DBG_TRAP, ("dotrap[%d]: %d pending, traps %sinvalid\n",
CTRACE(DBG_TRAP|DBG_SIG, ("dotrap[%d]: %d pending, traps %sinvalid\n",
in_dotrap, pendingsigs, traps_invalid ? "" : "not "));
in_dotrap++;
for (;;) {
pendingsigs = 0;
for (i = 1 ; ; i++) {
if (i >= NSIG)
if (i >= NSIG) {
in_dotrap--;
VTRACE(DBG_TRAP|DBG_SIG, ("dotrap[%d] done\n",
in_dotrap));
return;
}
if (gotsig[i])
break;
}
@ -722,8 +784,6 @@ dotrap(void)
}
}
}
in_dotrap--;
}
int