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-rw-r--r--source4/lib/select.c27
1 files changed, 18 insertions, 9 deletions
diff --git a/source4/lib/select.c b/source4/lib/select.c
index bed02304cc..066465c1be 100644
--- a/source4/lib/select.c
+++ b/source4/lib/select.c
@@ -100,20 +100,23 @@ int sys_select(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorfds, s
FD_ZERO(writefds);
if (errorfds)
FD_ZERO(errorfds);
- }
-
- if (FD_ISSET(select_pipe[0], readfds2)) {
+ } else if (FD_ISSET(select_pipe[0], readfds2)) {
char c;
saved_errno = errno;
if (read(select_pipe[0], &c, 1) == 1) {
pipe_read++;
- }
- errno = saved_errno;
- FD_CLR(select_pipe[0], readfds2);
- ret--;
- if (ret == 0) {
+ /* Mark Weaver <mark-clist@npsl.co.uk> pointed out a critical
+ fix to ensure we don't lose signals. We must always
+ return -1 when the select pipe is set, otherwise if another
+ fd is also ready (so ret == 2) then we used to eat the
+ byte in the pipe and lose the signal. JRA.
+ */
ret = -1;
errno = EINTR;
+ } else {
+ FD_CLR(select_pipe[0], readfds2);
+ ret--;
+ errno = saved_errno;
}
}
@@ -146,7 +149,13 @@ int sys_select_intr(int maxfd, fd_set *readfds, fd_set *writefds, fd_set *errorf
if (tval)
tval2 = *tval;
- ret = sys_select(maxfd, readfds2, writefds2, errorfds2, ptval);
+ /* We must use select and not sys_select here. If we use
+ sys_select we'd lose the fact a signal occurred when sys_select
+ read a byte from the pipe. Fix from Mark Weaver
+ <mark-clist@npsl.co.uk>
+ */
+
+ ret = select(maxfd, readfds2, writefds2, errorfds2, ptval);
} while (ret == -1 && errno == EINTR);
if (readfds)