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Don't do unsafe activities inside signal handlers. Just set a flag and

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return.

Obtained from:	OpenBSD
Reviewed by:	audit
This commit is contained in:
Kris Kennaway 2001-08-06 03:19:22 +00:00
parent b3a1f1765a
commit 26d889d4ff
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=81187
1 changed files with 54 additions and 44 deletions
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98
contrib/top/top.c
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@ -73,6 +73,10 @@ sigret_t tstop();
sigret_t winch();
#endif
volatile sig_atomic_t leaveflag;
volatile sig_atomic_t tstopflag;
volatile sig_atomic_t winchflag;
/* internal routines */
void quit();
@ -517,12 +521,7 @@ Usage: %s [-ISbinqut] [-d x] [-s x] [-o field] [-U username] [number]\n",
fputc('\n', stderr);
}
/* setup the jump buffer for stops */
if (setjmp(jmp_int) != 0)
{
/* control ends up here after an interrupt */
reset_display();
}
restart:
/*
* main loop -- repeat while display count is positive or while it
@ -665,6 +664,52 @@ Usage: %s [-ISbinqut] [-d x] [-s x] [-o field] [-U username] [number]\n",
timeout.tv_sec = delay;
timeout.tv_usec = 0;
if (leaveflag) {
end_screen();
exit(0);
}
if (tstopflag) {
/* move to the lower left */
end_screen();
fflush(stdout);
/* default the signal handler action */
(void) signal(SIGTSTP, SIG_DFL);
/* unblock the signal and send ourselves one */
#ifdef SIGRELSE
sigrelse(SIGTSTP);
#else
(void) sigsetmask(sigblock(0) & ~(1 << (SIGTSTP - 1)));
#endif
(void) kill(0, SIGTSTP);
/* reset the signal handler */
(void) signal(SIGTSTP, tstop);
/* reinit screen */
reinit_screen();
reset_display();
tstopflag = 0;
goto restart;
}
if (winchflag) {
/* reascertain the screen dimensions */
get_screensize();
/* tell display to resize */
max_topn = display_resize();
/* reset the signal handler */
(void) signal(SIGWINCH, winch);
reset_display();
winchflag = 0;
goto restart;
}
/* wait for either input or the end of the delay period */
if (select(32, &readfds, (fd_set *)NULL, (fd_set *)NULL, &timeout) > 0)
{
@ -949,8 +994,7 @@ reset_display()
sigret_t leave() /* exit under normal conditions -- INT handler */
{
end_screen();
exit(0);
leaveflag = 1;
}
sigret_t tstop(i) /* SIGTSTP handler */
@ -958,31 +1002,7 @@ sigret_t tstop(i) /* SIGTSTP handler */
int i;
{
/* move to the lower left */
end_screen();
fflush(stdout);
/* default the signal handler action */
(void) signal(SIGTSTP, SIG_DFL);
/* unblock the signal and send ourselves one */
#ifdef SIGRELSE
sigrelse(SIGTSTP);
#else
(void) sigsetmask(sigblock(0) & ~(1 << (SIGTSTP - 1)));
#endif
(void) kill(0, SIGTSTP);
/* reset the signal handler */
(void) signal(SIGTSTP, tstop);
/* reinit screen */
reinit_screen();
/* jump to appropriate place */
longjmp(jmp_int, 1);
/*NOTREACHED*/
tstopflag = 1;
}
#ifdef SIGWINCH
@ -991,17 +1011,7 @@ sigret_t winch(i) /* SIGWINCH handler */
int i;
{
/* reascertain the screen dimensions */
get_screensize();
/* tell display to resize */
max_topn = display_resize();
/* reset the signal handler */
(void) signal(SIGWINCH, winch);
/* jump to appropriate place */
longjmp(jmp_int, 1);
winchflag = 1;
}
#endif