From bbeb06a37ba58f6905803d32a26fb00953459301 Mon Sep 17 00:00:00 2001

From: "Barton E. Schaefer" <schaefer@zsh.org>

Date: Thu, 20 Mar 2014 07:56:30 -0700

Subject: [PATCH 1/8] 32500: handle interrupts during pattern matching

Upstream-commit: 8672d19f0c0f25569e233bbd466b6c39f60c7a55

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 Src/pattern.c | 8 +++++++-

 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Src/pattern.c b/Src/pattern.c

index b74a08a..b93b064 100644

--- a/Src/pattern.c

+++ b/Src/pattern.c

@@ -2128,6 +2128,8 @@ pattryrefs(Patprog prog, char *string, int stringlen, int unmetalen,

 	return ret;

     } else {

+	int q = queue_signal_level();

+

 	/*

 	 * Test for a `must match' string, unless we're scanning for a match

 	 * in which case we don't need to do this each time.

@@ -2175,6 +2177,8 @@ pattryrefs(Patprog prog, char *string, int stringlen, int unmetalen,

 	patinput = patinstart;

+	dont_queue_signals();

+

 	if (patmatch((Upat)progstr)) {

 	    /*

 	     * we were lazy and didn't save the globflags if an exclusion

@@ -2311,6 +2315,8 @@ pattryrefs(Patprog prog, char *string, int stringlen, int unmetalen,

 	} else

 	    ret = 0;

+	restore_queue_signals(q);

+

 	if (tryalloced)

 	    zfree(tryalloced, unmetalen + unmetalenp);

@@ -2390,7 +2396,7 @@ patmatch(Upat prog)

     zrange_t from, to, comp;

     patint_t nextch;

-    while  (scan) {

+    while  (scan && !errflag) {

 	next = PATNEXT(scan);

 	if (!globdots && P_NOTDOT(scan) && patinput == patinstart &&

-- 

2.5.0

From c3eeba82d560005d830862dace8d771e712693e6 Mon Sep 17 00:00:00 2001

From: "Barton E. Schaefer" <schaefer@zsh.org>

Date: Sun, 9 Aug 2015 00:50:36 -0700

Subject: [PATCH 2/8] 36022 fix bug that some loop constructs could not be

 interrupted, revise signal queueing

There are two underlying ideas here:  (1) Keeping signals queued around

anything that's doing memory management (including push/pop of the heap)

has become crucial.  (2) Anytime the shell is going to run a command, be

it buitin or external, it must be both safe and necessary to process any

queued signals, so that the apparent order of signal arrival and command

execution is preserved.

Upstream-commit: 9958684574bf8b0ecec6983cca57f3fa3dd7cd63

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 Src/exec.c    | 43 ++++++++++++++++++++++++++++++++++++++-----

 Src/init.c    |  5 +++++

 Src/input.c   |  9 +++++++++

 Src/loop.c    | 36 ++++++++++++++++++++++++++++++++++--

 Src/parse.c   |  8 ++++++++

 Src/signals.c |  8 ++++++--

 6 files changed, 100 insertions(+), 9 deletions(-)

diff --git a/Src/exec.c b/Src/exec.c

index 7817a64..cff1a24 100644

--- a/Src/exec.c

+++ b/Src/exec.c

@@ -1108,8 +1108,12 @@ execsimple(Estate state)

 	    fflush(xtrerr);

 	}

 	lv = (errflag ? errflag : cmdoutval);

-    } else

+    } else {

+	int q = queue_signal_level();

+	dont_queue_signals();

 	lv = (execfuncs[code - WC_CURSH])(state, 0);

+	restore_queue_signals(q);

+     }

     thisjob = otj;

@@ -1141,6 +1145,8 @@ execlist(Estate state, int dont_change_job, int exiting)

      */

     int oldnoerrexit = noerrexit;

+    queue_signals();

+

     cj = thisjob;

     old_pline_level = pline_level;

     old_list_pipe = list_pipe;

@@ -1391,6 +1397,8 @@ sublist_done:

 	/* Make sure this doesn't get executed again. */

 	sigtrapped[SIGEXIT] = 0;

     }

+

+    unqueue_signals();

 }

 /* Execute a pipeline.                                                *

@@ -1419,6 +1427,14 @@ execpline(Estate state, wordcode slcode, int how, int last1)

     else if (slflags & WC_SUBLIST_NOT)

 	last1 = 0;

+    /* If trap handlers are allowed to run here, they may start another

+     * external job in the middle of us starting this one, which can

+     * result in jobs being reaped before their job table entries have

+     * been initialized, which in turn leads to waiting forever for

+     * jobs that no longer exist.  So don't do that.

+     */

+    queue_signals();

+

     pj = thisjob;

     ipipe[0] = ipipe[1] = opipe[0] = opipe[1] = 0;

     child_block();

@@ -1431,6 +1447,7 @@ execpline(Estate state, wordcode slcode, int how, int last1)

      */

     if ((thisjob = newjob = initjob()) == -1) {

 	child_unblock();

+	unqueue_signals();

 	return 1;

     }

     if (how & Z_TIMED)

@@ -1486,6 +1503,7 @@ execpline(Estate state, wordcode slcode, int how, int last1)

 	else

 	    spawnjob();

 	child_unblock();

+	unqueue_signals();

 	/* Executing background code resets shell status */

 	return lastval = 0;

     } else {

@@ -1543,15 +1561,18 @@ execpline(Estate state, wordcode slcode, int how, int last1)

 		}

 		if (!(jn->stat & STAT_LOCKED)) {

 		    updated = hasprocs(thisjob);

-		    waitjobs();

+		    waitjobs();		/* deals with signal queue */

 		    child_block();

 		} else

 		    updated = 0;

 		if (!updated &&

 		    list_pipe_job && hasprocs(list_pipe_job) &&

 		    !(jobtab[list_pipe_job].stat & STAT_STOPPED)) {

+		    int q = queue_signal_level();

 		    child_unblock();

+		    dont_queue_signals();

 		    child_block();

+		    restore_queue_signals(q);

 		}

 		if (list_pipe_child &&

 		    jn->stat & STAT_DONE &&

@@ -1631,6 +1652,7 @@ execpline(Estate state, wordcode slcode, int how, int last1)

 		    break;

 	    }

 	    child_unblock();

+	    unqueue_signals();

 	    if (list_pipe && (lastval & 0200) && pj >= 0 &&

 		(!(jn->stat & STAT_INUSE) || (jn->stat & STAT_DONE))) {

@@ -3192,6 +3214,7 @@ execcmd(Estate state, int input, int output, int how, int last1)

 	    fflush(xtrerr);

 	}

     } else if (isset(EXECOPT) && !errflag) {

+	int q = queue_signal_level();

 	/*

 	 * We delay the entersubsh() to here when we are exec'ing

 	 * the current shell (including a fake exec to run a builtin then

@@ -3210,7 +3233,9 @@ execcmd(Estate state, int input, int output, int how, int last1)

 	if (type >= WC_CURSH) {

 	    if (last1 == 1)

 		do_exec = 1;

+	    dont_queue_signals();

 	    lastval = (execfuncs[type - WC_CURSH])(state, do_exec);

+	    restore_queue_signals(q);

 	} else if (is_builtin || is_shfunc) {

 	    LinkList restorelist = 0, removelist = 0;

 	    /* builtin or shell function */

@@ -3269,7 +3294,9 @@ execcmd(Estate state, int input, int output, int how, int last1)

 		/* It's a builtin */

 		if (forked)

 		    closem(FDT_INTERNAL);

+		dont_queue_signals();

 		lastval = execbuiltin(args, (Builtin) hn);

+		restore_queue_signals(q);

 #ifdef PATH_DEV_FD

 		closem(FDT_PROC_SUBST);

 #endif

@@ -4415,11 +4442,9 @@ execshfunc(Shfunc shf, LinkList args)

     if ((osfc = sfcontext) == SFC_NONE)

 	sfcontext = SFC_DIRECT;

     xtrerr = stderr;

-    unqueue_signals();

     doshfunc(shf, args, 0);

-    queue_signals();

     sfcontext = osfc;

     free(cmdstack);

     cmdstack = ocs;

@@ -4614,6 +4639,8 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)

     static int funcdepth;

 #endif

+    queue_signals();	/* Lots of memory and global state changes coming */

+

     pushheap();

     oargv0 = NULL;

@@ -4814,6 +4841,8 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)

     }

     popheap();

+    unqueue_signals();

+

     if (exit_pending) {

 	if (locallevel > forklevel) {

 	    /* Still functions to return: force them to do so. */

@@ -4844,6 +4873,8 @@ runshfunc(Eprog prog, FuncWrap wrap, char *name)

     int cont, ouu;

     char *ou;

+    queue_signals();

+

     ou = zalloc(ouu = underscoreused);

     if (ou)

 	memcpy(ou, zunderscore, underscoreused);

@@ -4865,12 +4896,14 @@ runshfunc(Eprog prog, FuncWrap wrap, char *name)

 	wrap = wrap->next;

     }

     startparamscope();

-    execode(prog, 1, 0, "shfunc");

+    execode(prog, 1, 0, "shfunc");	/* handles signal unqueueing */

     if (ou) {

 	setunderscore(ou);

 	zfree(ou, ouu);

     }

     endparamscope();

+

+    unqueue_signals();

 }

 /* Search fpath for an undefined function.  Finds the file, and returns the *

diff --git a/Src/init.c b/Src/init.c

index 78f171d..df42349 100644

--- a/Src/init.c

+++ b/Src/init.c

@@ -105,6 +105,7 @@ loop(int toplevel, int justonce)

     Eprog prog;

     int err, non_empty = 0;

+    queue_signals();

     pushheap();

     if (!toplevel)

 	lexsave();

@@ -118,7 +119,9 @@ loop(int toplevel, int justonce)

 	    if (interact && toplevel) {

 	        int hstop = stophist;

 		stophist = 3;

+		unqueue_signals();

 		preprompt();

+		queue_signals();

 		if (stophist != 3)

 		    hbegin(1);

 		else

@@ -197,6 +200,7 @@ loop(int toplevel, int justonce)

 	if (((!interact || sourcelevel) && errflag) || retflag)

 	    break;

 	if (isset(SINGLECOMMAND) && toplevel) {

+	    dont_queue_signals();

 	    if (sigtrapped[SIGEXIT])

 		dotrap(SIGEXIT);

 	    exit(lastval);

@@ -208,6 +212,7 @@ loop(int toplevel, int justonce)

     if (!toplevel)

 	lexrestore();

     popheap();

+    unqueue_signals();

     if (err)

 	return LOOP_ERROR;

diff --git a/Src/input.c b/Src/input.c

index 5b782dc..dcff78a 100644

--- a/Src/input.c

+++ b/Src/input.c

@@ -140,14 +140,17 @@ shingetline(void)

     int c;

     char buf[BUFSIZ];

     char *p;

+    int q = queue_signal_level();

     p = buf;

     for (;;) {

+	dont_queue_signals();

 	do {

 	    errno = 0;

 	    c = fgetc(bshin);

 	} while (c < 0 && errno == EINTR);

 	if (c < 0 || c == '\n') {

+	    restore_queue_signals(q);

 	    if (c == '\n')

 		*p++ = '\n';

 	    if (p > buf) {

@@ -163,11 +166,13 @@ shingetline(void)

 	} else

 	    *p++ = c;

 	if (p >= buf + BUFSIZ - 1) {

+	    queue_signals();

 	    line = zrealloc(line, ll + (p - buf) + 1);

 	    memcpy(line + ll, buf, p - buf);

 	    ll += p - buf;

 	    line[ll] = '\0';

 	    p = buf;

+	    unqueue_signals();

 	}

     }

 }

@@ -340,6 +345,8 @@ inputline(void)

 static void

 inputsetline(char *str, int flags)

 {

+    queue_signals();

+

     if ((inbufflags & INP_FREE) && inbuf) {

 	free(inbuf);

     }

@@ -357,6 +364,8 @@ inputsetline(char *str, int flags)

     else

 	inbufct = inbufleft;

     inbufflags = flags;

+

+    unqueue_signals();

 }

 /*

diff --git a/Src/loop.c b/Src/loop.c

index 90a0761..0c07c73 100644

--- a/Src/loop.c

+++ b/Src/loop.c

@@ -56,6 +56,10 @@ execfor(Estate state, int do_exec)

     char *name, *str, *cond = NULL, *advance = NULL;

     zlong val = 0;

     LinkList vars = NULL, args = NULL;

+    int old_simple_pline = simple_pline;

+

+    /* See comments in execwhile() */

+    simple_pline = 1;

     end = state->pc + WC_FOR_SKIP(code);

@@ -73,6 +77,7 @@ execfor(Estate state, int do_exec)

 	    matheval(str);

 	if (errflag) {

 	    state->pc = end;

+	    simple_pline = old_simple_pline;

 	    return lastval = errflag;

 	}

 	cond = ecgetstr(state, EC_NODUP, &ctok);

@@ -85,6 +90,7 @@ execfor(Estate state, int do_exec)

 	    if (!(args = ecgetlist(state, *state->pc++, EC_DUPTOK, &htok))) {

 		state->pc = end;

+		simple_pline = old_simple_pline;

 		return 0;

 	    }

 	    if (htok)

@@ -190,6 +196,7 @@ execfor(Estate state, int do_exec)

     popheap();

     cmdpop();

     loops--;

+    simple_pline = old_simple_pline;

     state->pc = end;

     return lastval;

 }

@@ -206,6 +213,10 @@ execselect(Estate state, UNUSED(int do_exec))

     FILE *inp;

     size_t more;

     LinkList args;

+    int old_simple_pline = simple_pline;

+

+    /* See comments in execwhile() */

+    simple_pline = 1;

     end = state->pc + WC_FOR_SKIP(code);

     name = ecgetstr(state, EC_NODUP, NULL);

@@ -221,6 +232,7 @@ execselect(Estate state, UNUSED(int do_exec))

 	if (!(args = ecgetlist(state, *state->pc++, EC_DUPTOK, &htok))) {

 	    state->pc = end;

+	    simple_pline = old_simple_pline;

 	    return 0;

 	}

 	if (htok)

@@ -228,6 +240,7 @@ execselect(Estate state, UNUSED(int do_exec))

     }

     if (!args || empty(args)) {

 	state->pc = end;

+	simple_pline = old_simple_pline;

 	return 1;

     }

     loops++;

@@ -301,6 +314,7 @@ execselect(Estate state, UNUSED(int do_exec))

     popheap();

     fclose(inp);

     loops--;

+    simple_pline = old_simple_pline;

     state->pc = end;

     return lastval;

 }

@@ -368,6 +382,7 @@ execwhile(Estate state, UNUSED(int do_exec))

     Wordcode end, loop;

     wordcode code = state->pc[-1];

     int olderrexit, oldval, isuntil = (WC_WHILE_TYPE(code) == WC_WHILE_UNTIL);

+    int old_simple_pline = simple_pline;

     end = state->pc + WC_WHILE_SKIP(code);

     olderrexit = noerrexit;

@@ -382,8 +397,6 @@ execwhile(Estate state, UNUSED(int do_exec))

         /* This is an empty loop.  Make sure the signal handler sets the

         * flags and then just wait for someone hitting ^C. */

-        int old_simple_pline = simple_pline;

-

         simple_pline = 1;

         while (!breaks)

@@ -395,7 +408,14 @@ execwhile(Estate state, UNUSED(int do_exec))

         for (;;) {

             state->pc = loop;

             noerrexit = 1;

+

+	    /* In case the test condition is a functional no-op,

+	     * make sure signal handlers recognize ^C to end the loop. */

+	    simple_pline = 1;

+

             execlist(state, 1, 0);

+

+	    simple_pline = old_simple_pline;

             noerrexit = olderrexit;

             if (!((lastval == 0) ^ isuntil)) {

                 if (breaks)

@@ -407,7 +427,14 @@ execwhile(Estate state, UNUSED(int do_exec))

                 lastval = oldval;

                 break;

             }

+

+	    /* In case the loop body is also a functional no-op,

+	     * make sure signal handlers recognize ^C as above. */

+	    simple_pline = 1;

+

             execlist(state, 1, 0);

+

+	    simple_pline = old_simple_pline;

             if (breaks) {

                 breaks--;

                 if (breaks || !contflag)

@@ -438,6 +465,10 @@ execrepeat(Estate state, UNUSED(int do_exec))

     wordcode code = state->pc[-1];

     int count, htok = 0;

     char *tmp;

+    int old_simple_pline = simple_pline;

+

+    /* See comments in execwhile() */

+    simple_pline = 1;

     end = state->pc + WC_REPEAT_SKIP(code);

@@ -470,6 +501,7 @@ execrepeat(Estate state, UNUSED(int do_exec))

     cmdpop();

     popheap();

     loops--;

+    simple_pline = old_simple_pline;

     state->pc = end;

     return lastval;

 }

diff --git a/Src/parse.c b/Src/parse.c

index b0a7624..04d2707 100644

--- a/Src/parse.c

+++ b/Src/parse.c

@@ -379,6 +379,8 @@ init_parse_status(void)

 void

 init_parse(void)

 {

+    queue_signals();

+

     if (ecbuf) zfree(ecbuf, eclen);

     ecbuf = (Wordcode) zalloc((eclen = EC_INIT_SIZE) * sizeof(wordcode));

@@ -389,6 +391,8 @@ init_parse(void)

     ecnfunc = 0;

     init_parse_status();

+

+    unqueue_signals();

 }

 /* Build eprog. */

@@ -409,6 +413,8 @@ bld_eprog(void)

     Eprog ret;

     int l;

+    queue_signals();

+

     ecadd(WCB_END());

     ret = (Eprog) zhalloc(sizeof(*ret));

@@ -431,6 +437,8 @@ bld_eprog(void)

     zfree(ecbuf, eclen);

     ecbuf = NULL;

+    unqueue_signals();

+

     return ret;

 }

diff --git a/Src/signals.c b/Src/signals.c

index c539063..73b41b1 100644

--- a/Src/signals.c

+++ b/Src/signals.c

@@ -1194,6 +1194,8 @@ dotrapargs(int sig, int *sigtr, void *sigfn)

 	}

     }

+    queue_signals();	/* Any time we manage memory or global state */

+

     intrap++;

     *sigtr |= ZSIG_IGNORED;

@@ -1231,7 +1233,7 @@ dotrapargs(int sig, int *sigtr, void *sigfn)

 	sfcontext = SFC_SIGNAL;

 	incompfunc = 0;

-	doshfunc((Shfunc)sigfn, args, 1);

+	doshfunc((Shfunc)sigfn, args, 1);	/* manages signal queueing */

 	sfcontext = osc;

 	incompfunc= old_incompfunc;

 	freelinklist(args, (FreeFunc) NULL);

@@ -1241,7 +1243,7 @@ dotrapargs(int sig, int *sigtr, void *sigfn)

 	trap_state = TRAP_STATE_PRIMED;

 	trapisfunc = isfunc = 0;

-	execode((Eprog)sigfn, 1, 0, "trap");

+	execode((Eprog)sigfn, 1, 0, "trap");	/* manages signal queueing */

     }

     runhookdef(AFTERTRAPHOOK, NULL);

@@ -1286,6 +1288,8 @@ dotrapargs(int sig, int *sigtr, void *sigfn)

     if (*sigtr != ZSIG_IGNORED)

 	*sigtr &= ~ZSIG_IGNORED;

     intrap--;

+

+    unqueue_signals();

 }

 /* Standard call to execute a trap for a given signal. */

-- 

2.5.0

From 33905958a1b94e83ca1c32bc6849906da94b91a6 Mon Sep 17 00:00:00 2001

From: "Barton E. Schaefer" <schaefer@zsh.org>

Date: Sun, 9 Aug 2015 17:37:23 -0700

Subject: [PATCH 3/8] 36033: a few more queue_signals() to protect global state

 changes

Upstream-commit: df5f825538720a9422859200d58d075d1dd075fc

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 Src/glob.c    | 4 ++++

 Src/pattern.c | 8 +++++++-

 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/Src/glob.c b/Src/glob.c

index ca2ffaf..9135fce 100644

--- a/Src/glob.c

+++ b/Src/glob.c

@@ -213,22 +213,26 @@ static struct globdata curglobdata;

 #define save_globstate(N) \

   do { \

+    queue_signals(); \

     memcpy(&(N), &curglobdata, sizeof(struct globdata)); \

     (N).gd_pathpos = pathpos; \

     (N).gd_pathbuf = pathbuf; \

     (N).gd_glob_pre = glob_pre; \

     (N).gd_glob_suf = glob_suf; \

     pathbuf = NULL; \

+    unqueue_signals(); \

   } while (0)

 #define restore_globstate(N) \

   do { \

+    queue_signals(); \

     zfree(pathbuf, pathbufsz); \

     memcpy(&curglobdata, &(N), sizeof(struct globdata)); \

     pathpos = (N).gd_pathpos; \

     pathbuf = (N).gd_pathbuf; \

     glob_pre = (N).gd_glob_pre; \

     glob_suf = (N).gd_glob_suf; \

+    unqueue_signals(); \

   } while (0)

 /* pathname component in filename patterns */

diff --git a/Src/pattern.c b/Src/pattern.c

index b74a08a..52774c0 100644

--- a/Src/pattern.c

+++ b/Src/pattern.c

@@ -452,6 +452,8 @@ patcompile(char *exp, int inflags, char **endexp)

     char *lng, *strp = NULL;

     Patprog p;

+    queue_signals();

+

     startoff = sizeof(struct patprog);

     /* Ensure alignment of start of program string */

     startoff = (startoff + sizeof(union upat) - 1) & ~(sizeof(union upat) - 1);

@@ -521,8 +523,10 @@ patcompile(char *exp, int inflags, char **endexp)

 	if (!strp || (*strp && *strp != '/')) {

 	    /* No, do normal compilation. */

 	    strp = NULL;

-	    if (patcompswitch(0, &flags) == 0)

+	    if (patcompswitch(0, &flags) == 0) {

+		unqueue_signals();

 		return NULL;

+	    }

 	} else {

 	    /*

 	     * Yes, copy the string, and skip compilation altogether.

@@ -654,6 +658,8 @@ patcompile(char *exp, int inflags, char **endexp)

     if (endexp)

 	*endexp = patparse;

+

+    unqueue_signals();

     return p;

 }

-- 

2.5.0

From bba38460c88c36fb529ee7494570cb2cfc68641a Mon Sep 17 00:00:00 2001

From: Peter Stephenson <pws@zsh.org>

Date: Mon, 10 Aug 2015 16:59:55 +0100

Subject: [PATCH 4/8] Don't rely on implicit value when saving background

 process status

Upstream-commit: a07f74fadd1180b42258d1fcec5359afe3f9ba00

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 Src/signals.c | 9 ++++++++-

 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Src/signals.c b/Src/signals.c

index 73b41b1..2e7304f 100644

--- a/Src/signals.c

+++ b/Src/signals.c

@@ -533,7 +533,14 @@ wait_for_processes(void)

 	 */

 	if (jn && !(jn->stat & (STAT_CURSH|STAT_BUILTIN)) &&

 	    jn - jobtab != thisjob)

-	    addbgstatus(pid, (int)lastval2);

+	{

+	    int val = (WIFSIGNALED(status) ?

+		   0200 | WTERMSIG(status) :

+		   (WIFSTOPPED(status) ?

+		    0200 | WEXITSTATUS(status) :

+		    WEXITSTATUS(status)));

+	    addbgstatus(pid, val);

+	}

 	unqueue_signals();

     }

-- 

2.5.0

From 530b59d58273c9f11cd1443c0865f6420eafcbf0 Mon Sep 17 00:00:00 2001

From: "Barton E. Schaefer" <schaefer@zsh.org>

Date: Tue, 11 Aug 2015 08:44:15 -0700

Subject: [PATCH 5/8] 36090: keep signals queued for preprompt()

Upstream-commit: 1af2e6e02d5cb8ca8d11f107b670cddfd10a7e81

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 Src/init.c | 2 --

 1 file changed, 2 deletions(-)

diff --git a/Src/init.c b/Src/init.c

index df42349..ca616d3 100644

--- a/Src/init.c

+++ b/Src/init.c

@@ -119,9 +119,7 @@ loop(int toplevel, int justonce)

 	    if (interact && toplevel) {

 	        int hstop = stophist;

 		stophist = 3;

-		unqueue_signals();

 		preprompt();

-		queue_signals();

 		if (stophist != 3)

 		    hbegin(1);

 		else

--