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top: address a defect with the library PROC_PID flag

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The library does not weed out potential duplicate PID
values when sampling with the PROC_PID flag.  This was
treated as merely an inefficiency by top and safely
ignored prior to the advent of forest view mode.

Now, however, if the -p switch duplicates certain PIDs,
*and* those processes have no PPID, *and* top's forest
view mode is active or activated, then a SEGV will be
generated (and caught).

This rather obscure buglet is thus limited to pid #1
(/sbin/init) and pid #2 (kthreadd).  With any other
duplicate PIDs the worse case scenario was a '?' in
place of the usual forest view artwork.

This commit silently ignores any duplicate process ids
and thereby avoids the potential segmemtation fault.

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2012-04-15 15:15:15 -05:00 committed by Craig Small
parent 421b08a4df
commit 39243fe306
1 changed files with 8 additions and 8 deletions
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16
top/top.c
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@ -2420,20 +2420,20 @@ static void parse_args (char **args) {
break;
case 'p':
if (Curwin->usrseltyp) error_exit(N_txt(SELECT_clash_txt));
do {
do { int i, pid;
if (cp[1]) cp++;
else if (*args) cp = *args++;
else error_exit(fmtmk(N_fmt(MISSING_args_fmt), ch));
if (Monpidsidx >= MONPIDMAX)
error_exit(fmtmk(N_fmt(LIMIT_exceed_fmt), MONPIDMAX));
if (1 != sscanf(cp, "%d", &Monpids[Monpidsidx])
|| 0 > Monpids[Monpidsidx])
if (1 != sscanf(cp, "%d", &pid) || 0 > pid)
error_exit(fmtmk(N_fmt(BAD_mon_pids_fmt), cp));
if (!Monpids[Monpidsidx])
Monpids[Monpidsidx] = getpid();
Monpidsidx++;
if (!(p = strchr(cp, ',')))
break;
if (!pid) pid = getpid();
for (i = 0; i < Monpidsidx; i++)
if (Monpids[i] == pid) goto next_pid;
Monpids[Monpidsidx++] = pid;
next_pid:
if (!(p = strchr(cp, ','))) break;
cp = p;
} while (*cp);
break;