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Fix some xgselect-vs-pselect bugs.

Browse source 
This may not fix Bug#17172, but it fixes some bugs discovering
while auditing xgselect.c for that bug.
when one of glib's file descriptors is greater than FDS_LIM.
Treat rfds, wfds, efds consistently, and test G_IO_PRI too.
Clear input masks when pselect returns zero.
This commit is contained in:
Paul Eggert 2014-04-15 08:43:41 -07:00
parent 20fa59a004
commit f5a312939f
2 changed files with 51 additions and 47 deletions
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15
src/ChangeLog
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@ -1,12 +1,11 @@
2014-04-15 Stefan Monnier <monnier@iro.umontreal.ca>
2014-04-15 Paul Eggert <eggert@penguin.cs.ucla.edu>
* buffer.c (Foverlays_at): Add argument `sorted'.
2014-04-14 Eli Zaretskii <eliz@gnu.org>
* insdel.c (invalidate_buffer_caches): When deleting or replacing
text, invalidate the bidi_paragraph_cache upto and including the
preceding newline.
Fix some xgselect-vs-pselect bugs (Bug#17172).
This may not fix Bug#17172, but it fixes some bugs discovering
while auditing xgselect.c for that bug.
when one of glib's file descriptors is greater than FDS_LIM.
Treat rfds, wfds, efds consistently, and test G_IO_PRI too.
Clear input masks when pselect returns zero.
2014-04-13 Paul Eggert <eggert@cs.ucla.edu>

83
src/xgselect.c
View file

@ -33,16 +33,15 @@ int
xg_select (int fds_lim, fd_set *rfds, fd_set *wfds, fd_set *efds,
struct timespec const *timeout, sigset_t const *sigmask)
{
fd_set all_rfds, all_wfds;
fd_set all_rfds, all_wfds, all_efds;
struct timespec tmo;
struct timespec const *tmop = timeout;
GMainContext *context;
int have_wfds = wfds != NULL;
GPollFD gfds_buf[128];
GPollFD *gfds = gfds_buf;
int gfds_size = sizeof gfds_buf / sizeof *gfds_buf;
int n_gfds, retval = 0, our_fds = 0, max_fds = fds_lim - 1;
int n_gfds, retval = 0, all_lim = fds_lim;
int i, nfds, tmo_in_millisec;
bool need_to_dispatch;
USE_SAFE_ALLOCA;
@ -59,6 +58,8 @@ xg_select (int fds_lim, fd_set *rfds, fd_set *wfds, fd_set *efds,
else FD_ZERO (&all_rfds);
if (wfds) all_wfds = *wfds;
else FD_ZERO (&all_wfds);
if (efds) all_efds = *efds;
else FD_ZERO (&all_efds);
n_gfds = g_main_context_query (context, G_PRIORITY_LOW, &tmo_in_millisec,
gfds, gfds_size);
@ -71,19 +72,22 @@ xg_select (int fds_lim, fd_set *rfds, fd_set *wfds, fd_set *efds,
}
for (i = 0; i < n_gfds; ++i)
{
if (gfds[i].events & G_IO_IN)
{
FD_SET (gfds[i].fd, &all_rfds);
if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
}
if (gfds[i].events & G_IO_OUT)
{
FD_SET (gfds[i].fd, &all_wfds);
if (gfds[i].fd > max_fds) max_fds = gfds[i].fd;
have_wfds = 1;
}
}
if (gfds[i].events & (G_IO_IN | G_IO_OUT | G_IO_PRI))
{
int fd = gfds[i].fd;
for (; all_lim <= fd; all_lim++)
{
FD_CLR (all_lim, &all_rfds);
FD_CLR (all_lim, &all_wfds);
FD_CLR (all_lim, &all_efds);
}
if (gfds[i].events & G_IO_IN)
FD_SET (fd, &all_rfds);
if (gfds[i].events & G_IO_OUT)
FD_SET (fd, &all_wfds);
if (gfds[i].events & G_IO_PRI)
FD_SET (fd, &all_efds);
}
SAFE_FREE ();
@ -95,34 +99,35 @@ xg_select (int fds_lim, fd_set *rfds, fd_set *wfds, fd_set *efds,
tmop = &tmo;
}
fds_lim = max_fds + 1;
nfds = pselect (fds_lim, &all_rfds, have_wfds ? &all_wfds : NULL,
efds, tmop, sigmask);
nfds = pselect (all_lim, &all_rfds, &all_wfds, &all_efds, tmop, sigmask);
if (nfds < 0)
retval = nfds;
else if (nfds > 0)
else
{
for (i = 0; i < fds_lim; ++i)
{
if (FD_ISSET (i, &all_rfds))
{
if (rfds && FD_ISSET (i, rfds)) ++retval;
else ++our_fds;
}
else if (rfds)
FD_CLR (i, rfds);
if (have_wfds && FD_ISSET (i, &all_wfds))
{
if (wfds && FD_ISSET (i, wfds)) ++retval;
else ++our_fds;
}
else if (wfds)
FD_CLR (i, wfds);
if (efds && FD_ISSET (i, efds))
++retval;
if (rfds && FD_ISSET (i, rfds))
{
if (FD_ISSET (i, &all_rfds))
retval++;
else
FD_CLR (i, rfds);
}
if (wfds && FD_ISSET (i, wfds))
{
if (FD_ISSET (i, &all_wfds))
retval++;
else
FD_CLR (i, wfds);
}
if (efds && FD_ISSET (i, efds))
{
if (FD_ISSET (i, &all_efds))
retval++;
else
FD_CLR (i, efds);
}
}
}
@ -142,7 +147,7 @@ xg_select (int fds_lim, fd_set *rfds, fd_set *wfds, fd_set *efds,
}
/* To not have to recalculate timeout, return like this. */
if ((our_fds > 0 || (nfds == 0 && tmop == &tmo)) && (retval == 0))
if (retval == 0 && (0 < nfds || tmop == &tmo))
{
retval = -1;
errno = EINTR;