441 lines
10 KiB
C
441 lines
10 KiB
C
/** $MirBSD: src/bin/ksh/trap.c,v 1.1 2004/12/10 18:08:08 tg Exp $ */
|
|
/* $OpenBSD: trap.c,v 1.13 2003/02/28 09:45:09 jmc Exp $ */
|
|
|
|
/*
|
|
* signal handling
|
|
*/
|
|
|
|
/* Kludge to avoid bogus re-declaration of sigtraps[] error on AIX 3.2.5 */
|
|
#define FROM_TRAP_C
|
|
#include "sh.h"
|
|
|
|
__RCSID("$MirBSD: src/bin/ksh/trap.c,v 1.1 2004/12/10 18:08:08 tg Exp $");
|
|
|
|
/* Table is indexed by signal number
|
|
*
|
|
* The script siglist.sh generates siglist.out, which is a sorted, complete
|
|
* list of signals
|
|
*/
|
|
Trap sigtraps[SIGNALS+1] = {
|
|
{ SIGEXIT_, "EXIT", "Signal 0", NULL, 0, 0, 0, 0 },
|
|
#include "siglist.out" /* generated by siglist.sh */
|
|
{ SIGERR_, "ERR", "Error handler", NULL, 0, 0, 0, 0 },
|
|
};
|
|
|
|
static struct sigaction Sigact_ign, Sigact_trap;
|
|
|
|
void
|
|
inittraps(void)
|
|
{
|
|
#ifdef HAVE_SYS_SIGLIST
|
|
# ifndef SYS_SIGLIST_DECLARED
|
|
extern char *sys_siglist[];
|
|
# endif
|
|
int i;
|
|
|
|
/* Use system description, if available, for unknown signals... */
|
|
for (i = 0; i < NSIG; i++)
|
|
if (!sigtraps[i].name && sys_siglist[i] && sys_siglist[i][0])
|
|
sigtraps[i].mess = sys_siglist[i];
|
|
#endif /* HAVE_SYS_SIGLIST */
|
|
|
|
sigemptyset(&Sigact_ign.sa_mask);
|
|
Sigact_ign.sa_flags = KSH_SA_FLAGS;
|
|
Sigact_ign.sa_handler = SIG_IGN;
|
|
Sigact_trap = Sigact_ign;
|
|
Sigact_trap.sa_handler = trapsig;
|
|
|
|
sigtraps[SIGINT].flags |= TF_DFL_INTR | TF_TTY_INTR;
|
|
sigtraps[SIGQUIT].flags |= TF_DFL_INTR | TF_TTY_INTR;
|
|
sigtraps[SIGTERM].flags |= TF_DFL_INTR;/* not fatal for interactive */
|
|
sigtraps[SIGHUP].flags |= TF_FATAL;
|
|
sigtraps[SIGCHLD].flags |= TF_SHELL_USES;
|
|
|
|
/* these are always caught so we can clean up any temporary files. */
|
|
setsig(&sigtraps[SIGINT], trapsig, SS_RESTORE_ORIG);
|
|
setsig(&sigtraps[SIGQUIT], trapsig, SS_RESTORE_ORIG);
|
|
setsig(&sigtraps[SIGTERM], trapsig, SS_RESTORE_ORIG);
|
|
setsig(&sigtraps[SIGHUP], trapsig, SS_RESTORE_ORIG);
|
|
}
|
|
|
|
#ifdef KSH
|
|
static RETSIGTYPE alarm_catcher(int sig);
|
|
|
|
void
|
|
alarm_init(void)
|
|
{
|
|
sigtraps[SIGALRM].flags |= TF_SHELL_USES;
|
|
setsig(&sigtraps[SIGALRM], alarm_catcher,
|
|
SS_RESTORE_ORIG|SS_FORCE|SS_SHTRAP);
|
|
}
|
|
|
|
static RETSIGTYPE
|
|
alarm_catcher(int sig GCC_FUNC_ATTR(unused))
|
|
{
|
|
int errno_ = errno;
|
|
|
|
if (ksh_tmout_state == TMOUT_READING) {
|
|
int left = alarm(0);
|
|
|
|
if (left == 0) {
|
|
ksh_tmout_state = TMOUT_LEAVING;
|
|
intrsig = 1;
|
|
} else
|
|
alarm(left);
|
|
}
|
|
errno = errno_;
|
|
return RETSIGVAL;
|
|
}
|
|
#endif /* KSH */
|
|
|
|
Trap *
|
|
gettrap(const char *name, int igncase)
|
|
{
|
|
int i;
|
|
Trap *p;
|
|
|
|
if (digit(*name)) {
|
|
int n;
|
|
|
|
if (getn(name, &n) && 0 <= n && n < SIGNALS)
|
|
return &sigtraps[n];
|
|
return NULL;
|
|
}
|
|
for (p = sigtraps, i = SIGNALS+1; --i >= 0; p++)
|
|
if (p->name) {
|
|
if (igncase) {
|
|
if (p->name && (!strcasecmp(p->name, name) ||
|
|
(strlen(name) > 3 && !strncasecmp("SIG",
|
|
p->name, 3) &&
|
|
!strcasecmp(p->name, name + 3))))
|
|
return p;
|
|
} else {
|
|
if (p->name && (!strcmp(p->name, name) ||
|
|
(strlen(name) > 3 && !strncmp("SIG",
|
|
p->name, 3) && !strcmp(p->name, name + 3))))
|
|
return p;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* trap signal handler
|
|
*/
|
|
RETSIGTYPE
|
|
trapsig(int i)
|
|
{
|
|
Trap *p = &sigtraps[i];
|
|
int errno_ = errno;
|
|
|
|
trap = p->set = 1;
|
|
if (p->flags & TF_DFL_INTR)
|
|
intrsig = 1;
|
|
if ((p->flags & TF_FATAL) && !p->trap) {
|
|
fatal_trap = 1;
|
|
intrsig = 1;
|
|
}
|
|
if (p->shtrap)
|
|
(*p->shtrap)(i);
|
|
#ifdef V7_SIGNALS
|
|
if (sigtraps[i].cursig == trapsig) /* this for SIGCHLD,SIGALRM */
|
|
sigaction(i, &Sigact_trap, (struct sigaction *) 0);
|
|
#endif /* V7_SIGNALS */
|
|
errno = errno_;
|
|
return RETSIGVAL;
|
|
}
|
|
|
|
/* called when we want to allow the user to ^C out of something - won't
|
|
* work if user has trapped SIGINT.
|
|
*/
|
|
void
|
|
intrcheck(void)
|
|
{
|
|
if (intrsig)
|
|
runtraps(TF_DFL_INTR|TF_FATAL);
|
|
}
|
|
|
|
/* called after EINTR to check if a signal with normally causes process
|
|
* termination has been received.
|
|
*/
|
|
int
|
|
fatal_trap_check(void)
|
|
{
|
|
int i;
|
|
Trap *p;
|
|
|
|
/* todo: should check if signal is fatal, not the TF_DFL_INTR flag */
|
|
for (p = sigtraps, i = SIGNALS+1; --i >= 0; p++)
|
|
if (p->set && (p->flags & (TF_DFL_INTR|TF_FATAL)))
|
|
/* return value is used as an exit code */
|
|
return 128 + p->signal;
|
|
return 0;
|
|
}
|
|
|
|
/* Returns the signal number of any pending traps: ie, a signal which has
|
|
* occurred for which a trap has been set or for which the TF_DFL_INTR flag
|
|
* is set.
|
|
*/
|
|
int
|
|
trap_pending(void)
|
|
{
|
|
int i;
|
|
Trap *p;
|
|
|
|
for (p = sigtraps, i = SIGNALS+1; --i >= 0; p++)
|
|
if (p->set && ((p->trap && p->trap[0])
|
|
|| ((p->flags & (TF_DFL_INTR|TF_FATAL))
|
|
&& !p->trap)))
|
|
return p->signal;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* run any pending traps. If intr is set, only run traps that
|
|
* can interrupt commands.
|
|
*/
|
|
void
|
|
runtraps(int flag)
|
|
{
|
|
int i;
|
|
Trap *p;
|
|
|
|
#ifdef KSH
|
|
if (ksh_tmout_state == TMOUT_LEAVING) {
|
|
ksh_tmout_state = TMOUT_EXECUTING;
|
|
warningf(FALSE, "timed out waiting for input");
|
|
unwind(LEXIT);
|
|
} else
|
|
/* XXX: this means the alarm will have no effect if a trap
|
|
* is caught after the alarm() was started...not good.
|
|
*/
|
|
ksh_tmout_state = TMOUT_EXECUTING;
|
|
#endif /* KSH */
|
|
if (!flag)
|
|
trap = 0;
|
|
if (flag & TF_DFL_INTR)
|
|
intrsig = 0;
|
|
if (flag & TF_FATAL)
|
|
fatal_trap = 0;
|
|
for (p = sigtraps, i = SIGNALS+1; --i >= 0; p++)
|
|
if (p->set && (!flag
|
|
|| ((p->flags & flag) && p->trap == (char *) 0)))
|
|
runtrap(p);
|
|
}
|
|
|
|
void
|
|
runtrap(Trap *p)
|
|
{
|
|
int i = p->signal;
|
|
char *trapstr = p->trap;
|
|
int oexstat;
|
|
int UNINITIALIZED(old_changed);
|
|
|
|
p->set = 0;
|
|
if (trapstr == (char *) 0) { /* SIG_DFL */
|
|
if (p->flags & TF_FATAL) {
|
|
/* eg, SIGHUP */
|
|
exstat = 128 + i;
|
|
unwind(LLEAVE);
|
|
}
|
|
if (p->flags & TF_DFL_INTR) {
|
|
/* eg, SIGINT, SIGQUIT, SIGTERM, etc. */
|
|
exstat = 128 + i;
|
|
unwind(LINTR);
|
|
}
|
|
return;
|
|
}
|
|
if (trapstr[0] == '\0') /* SIG_IGN */
|
|
return;
|
|
if (i == SIGEXIT_ || i == SIGERR_) { /* avoid recursion on these */
|
|
old_changed = p->flags & TF_CHANGED;
|
|
p->flags &= ~TF_CHANGED;
|
|
p->trap = (char *) 0;
|
|
}
|
|
oexstat = exstat;
|
|
/* Note: trapstr is fully parsed before anything is executed, thus
|
|
* no problem with afree(p->trap) in settrap() while still in use.
|
|
*/
|
|
command(trapstr);
|
|
exstat = oexstat;
|
|
if (i == SIGEXIT_ || i == SIGERR_) {
|
|
if (p->flags & TF_CHANGED)
|
|
/* don't clear TF_CHANGED */
|
|
afree(trapstr, APERM);
|
|
else
|
|
p->trap = trapstr;
|
|
p->flags |= old_changed;
|
|
}
|
|
}
|
|
|
|
/* clear pending traps and reset user's trap handlers; used after fork(2) */
|
|
void
|
|
cleartraps(void)
|
|
{
|
|
int i;
|
|
Trap *p;
|
|
|
|
trap = 0;
|
|
intrsig = 0;
|
|
fatal_trap = 0;
|
|
for (i = SIGNALS+1, p = sigtraps; --i >= 0; p++) {
|
|
p->set = 0;
|
|
if ((p->flags & TF_USER_SET) && (p->trap && p->trap[0]))
|
|
settrap(p, (char *) 0);
|
|
}
|
|
}
|
|
|
|
/* restore signals just before an exec(2) */
|
|
void
|
|
restoresigs(void)
|
|
{
|
|
int i;
|
|
Trap *p;
|
|
|
|
for (i = SIGNALS+1, p = sigtraps; --i >= 0; p++)
|
|
if (p->flags & (TF_EXEC_IGN|TF_EXEC_DFL))
|
|
setsig(p, (p->flags & TF_EXEC_IGN) ? SIG_IGN : SIG_DFL,
|
|
SS_RESTORE_CURR|SS_FORCE);
|
|
}
|
|
|
|
void
|
|
settrap(Trap *p, char *s)
|
|
{
|
|
handler_t f;
|
|
|
|
if (p->trap)
|
|
afree(p->trap, APERM);
|
|
p->trap = str_save(s, APERM); /* handles s == 0 */
|
|
p->flags |= TF_CHANGED;
|
|
f = !s ? SIG_DFL : s[0] ? trapsig : SIG_IGN;
|
|
|
|
p->flags |= TF_USER_SET;
|
|
if ((p->flags & (TF_DFL_INTR|TF_FATAL)) && f == SIG_DFL)
|
|
f = trapsig;
|
|
else if (p->flags & TF_SHELL_USES) {
|
|
if (!(p->flags & TF_ORIG_IGN) || Flag(FTALKING)) {
|
|
/* do what user wants at exec time */
|
|
p->flags &= ~(TF_EXEC_IGN|TF_EXEC_DFL);
|
|
if (f == SIG_IGN)
|
|
p->flags |= TF_EXEC_IGN;
|
|
else
|
|
p->flags |= TF_EXEC_DFL;
|
|
}
|
|
/* assumes handler already set to what shell wants it
|
|
* (normally trapsig, but could be j_sigchld() or SIG_IGN)
|
|
*/
|
|
return;
|
|
}
|
|
|
|
/* todo: should we let user know signal is ignored? how? */
|
|
setsig(p, f, SS_RESTORE_CURR|SS_USER);
|
|
}
|
|
|
|
/* Called by c_print() when writing to a co-process to ensure SIGPIPE won't
|
|
* kill shell (unless user catches it and exits)
|
|
*/
|
|
int
|
|
block_pipe(void)
|
|
{
|
|
int restore_dfl = 0;
|
|
Trap *p = &sigtraps[SIGPIPE];
|
|
|
|
if (!(p->flags & (TF_ORIG_IGN|TF_ORIG_DFL))) {
|
|
setsig(p, SIG_IGN, SS_RESTORE_CURR);
|
|
if (p->flags & TF_ORIG_DFL)
|
|
restore_dfl = 1;
|
|
} else if (p->cursig == SIG_DFL) {
|
|
setsig(p, SIG_IGN, SS_RESTORE_CURR);
|
|
restore_dfl = 1; /* restore to SIG_DFL */
|
|
}
|
|
return restore_dfl;
|
|
}
|
|
|
|
/* Called by c_print() to undo whatever block_pipe() did */
|
|
void
|
|
restore_pipe(int restore_dfl)
|
|
{
|
|
if (restore_dfl)
|
|
setsig(&sigtraps[SIGPIPE], SIG_DFL, SS_RESTORE_CURR);
|
|
}
|
|
|
|
/* Set action for a signal. Action may not be set if original
|
|
* action was SIG_IGN, depending on the value of flags and
|
|
* FTALKING.
|
|
*/
|
|
int
|
|
setsig(Trap *p, handler_t f, int flags)
|
|
{
|
|
struct sigaction sigact;
|
|
|
|
if (p->signal == SIGEXIT_ || p->signal == SIGERR_)
|
|
return 1;
|
|
|
|
/* First time setting this signal? If so, get and note the current
|
|
* setting.
|
|
*/
|
|
if (!(p->flags & (TF_ORIG_IGN|TF_ORIG_DFL))) {
|
|
sigaction(p->signal, &Sigact_ign, &sigact);
|
|
p->flags |= sigact.sa_handler == SIG_IGN ?
|
|
TF_ORIG_IGN : TF_ORIG_DFL;
|
|
p->cursig = SIG_IGN;
|
|
}
|
|
|
|
/* Generally, an ignored signal stays ignored, except if
|
|
* - the user of an interactive shell wants to change it
|
|
* - the shell wants for force a change
|
|
*/
|
|
if ((p->flags & TF_ORIG_IGN) && !(flags & SS_FORCE)
|
|
&& (!(flags & SS_USER) || !Flag(FTALKING)))
|
|
return 0;
|
|
|
|
setexecsig(p, flags & SS_RESTORE_MASK);
|
|
|
|
/* This is here 'cause there should be a way of clearing shtraps, but
|
|
* don't know if this is a sane way of doing it. At the moment,
|
|
* all users of shtrap are lifetime users (SIGCHLD, SIGALRM, SIGWINCH).
|
|
*/
|
|
if (!(flags & SS_USER))
|
|
p->shtrap = (handler_t) 0;
|
|
if (flags & SS_SHTRAP) {
|
|
p->shtrap = f;
|
|
f = trapsig;
|
|
}
|
|
|
|
if (p->cursig != f) {
|
|
p->cursig = f;
|
|
sigemptyset(&sigact.sa_mask);
|
|
sigact.sa_flags = KSH_SA_FLAGS;
|
|
sigact.sa_handler = f;
|
|
sigaction(p->signal, &sigact, (struct sigaction *) 0);
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* control what signal is set to before an exec() */
|
|
void
|
|
setexecsig(Trap *p, int restore)
|
|
{
|
|
/* XXX debugging */
|
|
if (!(p->flags & (TF_ORIG_IGN|TF_ORIG_DFL)))
|
|
internal_errorf(1, "setexecsig: unset signal %d(%s)",
|
|
p->signal, p->name);
|
|
|
|
/* restore original value for exec'd kids */
|
|
p->flags &= ~(TF_EXEC_IGN|TF_EXEC_DFL);
|
|
switch (restore & SS_RESTORE_MASK) {
|
|
case SS_RESTORE_CURR: /* leave things as they currently are */
|
|
break;
|
|
case SS_RESTORE_ORIG:
|
|
p->flags |= p->flags & TF_ORIG_IGN ? TF_EXEC_IGN : TF_EXEC_DFL;
|
|
break;
|
|
case SS_RESTORE_DFL:
|
|
p->flags |= TF_EXEC_DFL;
|
|
break;
|
|
case SS_RESTORE_IGN:
|
|
p->flags |= TF_EXEC_IGN;
|
|
break;
|
|
}
|
|
}
|