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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.
This commit is contained in:
Barton E. Schaefer 2015-08-09 00:50:36 -07:00
parent ce12868837
commit 9958684574
7 changed files with 119 additions and 14 deletions
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10
ChangeLog
View File

@ -14,6 +14,16 @@
understanding what the command context code is attempting to do
after a command separator.
2015-08-09 Barton E. Schaefer <schaefer@zsh.org>
* 36022: Src/loop.c: fix bug that some loop constructs could
not be interrupted if all they did was variable assignments or
math expressions
* 36022: Src/exec.c, Src/init.c, Src/input.c, Src/parse.c,
Src/signals.c: revise signal queueing to better control the
circumtances in which trap handlers are executed
2015-08-08 Daniel Shahaf <d.s@daniel.shahaf.name>
* 36008: Src/builtin.c: trap: Fix listing of traps created

49
Src/exec.c
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@ -1121,10 +1121,14 @@ execsimple(Estate state)
fflush(xtrerr);
}
lv = (errflag ? errflag : cmdoutval);
} else if (code == WC_FUNCDEF) {
lv = execfuncdef(state, NULL);
} else {
lv = (execfuncs[code - WC_CURSH])(state, 0);
int q = queue_signal_level();
dont_queue_signals();
if (code == WC_FUNCDEF)
lv = execfuncdef(state, NULL);
else
lv = (execfuncs[code - WC_CURSH])(state, 0);
restore_queue_signals(q);
}
thisjob = otj;
@ -1158,6 +1162,8 @@ 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;
@ -1428,6 +1434,8 @@ sublist_done:
/* Make sure this doesn't get executed again. */
sigtrapped[SIGEXIT] = 0;
}
unqueue_signals();
}
/* Execute a pipeline. *
@ -1456,6 +1464,14 @@ 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();
@ -1468,6 +1484,7 @@ execpline(Estate state, wordcode slcode, int how, int last1)
*/
if ((thisjob = newjob = initjob()) == -1) {
child_unblock();
unqueue_signals();
return 1;
}
if (how & Z_TIMED)
@ -1523,6 +1540,7 @@ 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 {
@ -1580,15 +1598,18 @@ 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 &&
@ -1672,6 +1693,7 @@ 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))) {
@ -3391,6 +3413,7 @@ 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
@ -3431,11 +3454,14 @@ execcmd(Estate state, int input, int output, int how, int last1)
} else
redir_prog = NULL;
dont_queue_signals();
lastval = execfuncdef(state, redir_prog);
restore_queue_signals(q);
}
else if (type >= WC_CURSH) {
if (last1 == 1)
do_exec = 1;
dont_queue_signals();
if (type == WC_AUTOFN) {
/*
* We pre-loaded this to get any redirs.
@ -3444,6 +3470,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
lastval = execautofn_basic(state, do_exec);
} else
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 */
@ -3610,7 +3637,9 @@ execcmd(Estate state, int input, int output, int how, int last1)
}
state->pc = opc;
}
dont_queue_signals();
lastval = execbuiltin(args, assigns, (Builtin) hn);
restore_queue_signals(q);
fflush(stdout);
if (save[1] == -2) {
if (ferror(stdout)) {
@ -4820,11 +4849,9 @@ 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;
@ -5039,6 +5066,8 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
static int funcdepth;
#endif
queue_signals(); /* Lots of memory and global state changes coming */
pushheap();
oargv0 = NULL;
@ -5261,6 +5290,8 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
}
popheap();
unqueue_signals();
/*
* Exit with a tidy up.
* Only leave if we're at the end of the appropriate function ---
@ -5299,6 +5330,8 @@ runshfunc(Eprog prog, FuncWrap wrap, char *name)
int cont, ouu;
char *ou;
queue_signals();
ou = zalloc(ouu = underscoreused);
if (ou)
memcpy(ou, zunderscore, underscoreused);
@ -5320,12 +5353,14 @@ 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 *

5
Src/init.c
View File

@ -105,6 +105,7 @@ loop(int toplevel, int justonce)
Eprog prog;
int err, non_empty = 0;
queue_signals();
pushheap();
if (!toplevel)
zcontext_save();
@ -126,7 +127,9 @@ loop(int toplevel, int justonce)
* no matter what.
*/
errflag = 0;
unqueue_signals();
preprompt();
queue_signals();
if (stophist != 3)
hbegin(1);
else
@ -218,6 +221,7 @@ 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);
@ -229,6 +233,7 @@ loop(int toplevel, int justonce)
if (!toplevel)
zcontext_restore();
popheap();
unqueue_signals();
if (err)
return LOOP_ERROR;

12
Src/input.c
View File

@ -141,16 +141,19 @@ shingetline(void)
int c;
char buf[BUFSIZ];
char *p;
int q = queue_signal_level();
p = buf;
winch_unblock();
for (;;) {
winch_unblock();
dont_queue_signals();
do {
errno = 0;
c = fgetc(bshin);
} while (c < 0 && errno == EINTR);
if (c < 0 || c == '\n') {
winch_block();
restore_queue_signals(q);
if (c == '\n')
*p++ = '\n';
if (p > buf) {
@ -167,12 +170,13 @@ shingetline(void)
*p++ = c;
if (p >= buf + BUFSIZ - 1) {
winch_block();
queue_signals();
line = zrealloc(line, ll + (p - buf) + 1);
memcpy(line + ll, buf, p - buf);
ll += p - buf;
line[ll] = '\0';
p = buf;
winch_unblock();
unqueue_signals();
}
}
}
@ -377,6 +381,8 @@ inputline(void)
static void
inputsetline(char *str, int flags)
{
queue_signals();
if ((inbufflags & INP_FREE) && inbuf) {
free(inbuf);
}
@ -394,6 +400,8 @@ inputsetline(char *str, int flags)
else
inbufct = inbufleft;
inbufflags = flags;
unqueue_signals();
}
/*

41
Src/loop.c
View File

@ -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);
@ -69,10 +73,12 @@ execfor(Estate state, int do_exec)
fprintf(xtrerr, "%s\n", str2);
fflush(xtrerr);
}
if (!errflag)
if (!errflag) {
matheval(str);
}
if (errflag) {
state->pc = end;
simple_pline = old_simple_pline;
return 1;
}
cond = ecgetstr(state, EC_NODUP, &ctok);
@ -85,12 +91,14 @@ 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) {
execsubst(args);
if (errflag) {
state->pc = end;
simple_pline = old_simple_pline;
return 1;
}
}
@ -198,6 +206,7 @@ execfor(Estate state, int do_exec)
popheap();
cmdpop();
loops--;
simple_pline = old_simple_pline;
state->pc = end;
return lastval;
}
@ -214,6 +223,10 @@ 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);
@ -229,18 +242,21 @@ 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) {
execsubst(args);
if (errflag) {
state->pc = end;
simple_pline = old_simple_pline;
return 1;
}
}
}
if (!args || empty(args)) {
state->pc = end;
simple_pline = old_simple_pline;
return 0;
}
loops++;
@ -315,6 +331,7 @@ execselect(Estate state, UNUSED(int do_exec))
popheap();
fclose(inp);
loops--;
simple_pline = old_simple_pline;
state->pc = end;
return lastval;
}
@ -382,6 +399,7 @@ 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;
@ -396,8 +414,6 @@ 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)
@ -409,7 +425,14 @@ 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)
@ -421,7 +444,14 @@ 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)
@ -452,6 +482,10 @@ 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);
@ -484,6 +518,7 @@ execrepeat(Estate state, UNUSED(int do_exec))
cmdpop();
popheap();
loops--;
simple_pline = old_simple_pline;
state->pc = end;
return lastval;
}

8
Src/parse.c
View File

@ -456,6 +456,8 @@ init_parse_status(void)
void
init_parse(void)
{
queue_signals();
if (ecbuf) zfree(ecbuf, eclen);
ecbuf = (Wordcode) zalloc((eclen = EC_INIT_SIZE) * sizeof(wordcode));
@ -466,6 +468,8 @@ init_parse(void)
ecnfunc = 0;
init_parse_status();
unqueue_signals();
}
/* Build eprog. */
@ -488,6 +492,8 @@ bld_eprog(int heap)
Eprog ret;
int l;
queue_signals();
ecadd(WCB_END());
ret = heap ? (Eprog) zhalloc(sizeof(*ret)) : (Eprog) zalloc(sizeof(*ret));
@ -511,6 +517,8 @@ bld_eprog(int heap)
zfree(ecbuf, eclen);
ecbuf = NULL;
unqueue_signals();
return ret;
}

8
Src/signals.c
View File

@ -1207,6 +1207,8 @@ dotrapargs(int sig, int *sigtr, void *sigfn)
}
}
queue_signals(); /* Any time we manage memory or global state */
intrap++;
*sigtr |= ZSIG_IGNORED;
@ -1244,7 +1246,7 @@ 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);
@ -1254,7 +1256,7 @@ 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);
@ -1321,6 +1323,8 @@ 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. */