Adding upstream version 1:9.2p1.upstream/1%9.2p1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 205 insertions, 0 deletions

diff --git a/openbsd-compat/bsd-pselect.c b/openbsd-compat/bsd-pselect.c
new file mode 100644
index 0000000..b363208
--- /dev/null
+++ b/openbsd-compat/bsd-pselect.c
@@ -0,0 +1,205 @@
+/*
+ * Copyright (c) 2001 Markus Friedl.  All rights reserved.
+ * Copyright (c) 2021 Darren Tucker (dtucker at dtucker net).
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+#ifndef HAVE_PSELECT
+
+#include <sys/types.h>
+#include <sys/time.h>
+#ifdef HAVE_SYS_SELECT_H
+# include <sys/select.h>
+#endif
+
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "log.h"
+#include "misc.h"      /* for set_nonblock */
+
+#ifndef HAVE_SIGHANDLER_T
+typedef void (*sighandler_t)(int);
+#endif
+
+static sighandler_t saved_sighandler[_NSIG];
+
+/*
+ * Set up the descriptors.  Because they are close-on-exec, in the case
+ * where sshd's re-exec fails notify_pipe will still point to a descriptor
+ * that was closed by the exec attempt but if that descriptor has been
+ * reopened then we'll attempt to use that.  Ensure that notify_pipe is
+ * outside of the range used by sshd re-exec but within NFDBITS (so we don't
+ * need to expand the fd_sets).
+ */
+#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
+static int
+pselect_notify_setup_fd(int *fd)
+{
+	int r;
+
+	if ((r = fcntl(*fd, F_DUPFD, REEXEC_MIN_FREE_FD)) < 0 ||
+	    fcntl(r, F_SETFD, FD_CLOEXEC) < 0 || r >= FD_SETSIZE)
+		return -1;
+	(void)close(*fd);
+	return (*fd = r);
+}
+
+/*
+ * we write to this pipe if a SIGCHLD is caught in order to avoid
+ * the race between select() and child_terminated
+ */
+static pid_t notify_pid;
+static int notify_pipe[2];
+static void
+pselect_notify_setup(void)
+{
+	static int initialized;
+
+	if (initialized && notify_pid == getpid())
+		return;
+	if (notify_pid == 0)
+		debug3_f("initializing");
+	else {
+		debug3_f("pid changed, reinitializing");
+		if (notify_pipe[0] != -1)
+			close(notify_pipe[0]);
+		if (notify_pipe[1] != -1)
+			close(notify_pipe[1]);
+	}
+	if (pipe(notify_pipe) == -1) {
+		error("pipe(notify_pipe) failed %s", strerror(errno));
+	} else if (pselect_notify_setup_fd(&notify_pipe[0]) == -1 ||
+	    pselect_notify_setup_fd(&notify_pipe[1]) == -1) {
+		error("fcntl(notify_pipe, ...) failed %s", strerror(errno));
+		close(notify_pipe[0]);
+		close(notify_pipe[1]);
+	} else {
+		set_nonblock(notify_pipe[0]);
+		set_nonblock(notify_pipe[1]);
+		notify_pid = getpid();
+		debug3_f("pid %d saved %d pipe0 %d pipe1 %d", getpid(),
+		    notify_pid, notify_pipe[0], notify_pipe[1]);
+		initialized = 1;
+		return;
+	}
+	notify_pipe[0] = -1;    /* read end */
+	notify_pipe[1] = -1;    /* write end */
+}
+static void
+pselect_notify_parent(void)
+{
+	if (notify_pipe[1] != -1)
+		(void)write(notify_pipe[1], "", 1);
+}
+static void
+pselect_notify_prepare(fd_set *readset)
+{
+	if (notify_pipe[0] != -1)
+		FD_SET(notify_pipe[0], readset);
+}
+static void
+pselect_notify_done(fd_set *readset)
+{
+	char c;
+
+	if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset)) {
+		while (read(notify_pipe[0], &c, 1) != -1)
+			debug2_f("reading");
+		FD_CLR(notify_pipe[0], readset);
+	}
+}
+
+/*ARGSUSED*/
+static void
+pselect_sig_handler(int sig)
+{
+	int save_errno = errno;
+
+	pselect_notify_parent();
+	if (saved_sighandler[sig] != NULL)
+		(*saved_sighandler[sig])(sig);  /* call original handler */
+	errno = save_errno;
+}
+
+/*
+ * A minimal implementation of pselect(2), built on top of select(2).
+ */
+
+int
+pselect(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
+    const struct timespec *timeout, const sigset_t *mask)
+{
+	int ret, sig, saved_errno, unmasked = 0;
+	sigset_t osig;
+	struct sigaction sa, osa;
+	struct timeval tv, *tvp = NULL;
+
+	if (timeout != NULL) {
+		tv.tv_sec = timeout->tv_sec;
+		tv.tv_usec = timeout->tv_nsec / 1000;
+		tvp = &tv;
+	}
+	if (mask == NULL)  /* no signal mask, just call select */
+		return select(nfds, readfds, writefds, exceptfds, tvp);
+
+	/* For each signal we're unmasking, install our handler if needed. */
+	for (sig = 0; sig < _NSIG; sig++) {
+		if (sig == SIGKILL || sig == SIGSTOP || sigismember(mask, sig))
+			continue;
+		if (sigaction(sig, NULL, &sa) == 0 &&
+		    sa.sa_handler != SIG_IGN && sa.sa_handler != SIG_DFL) {
+			unmasked = 1;
+			if (sa.sa_handler == pselect_sig_handler)
+				continue;
+			sa.sa_handler = pselect_sig_handler;
+			if (sigaction(sig, &sa, &osa) == 0) {
+				debug3_f("installing signal handler for %s, "
+				    "previous %p", strsignal(sig),
+				     osa.sa_handler);
+				saved_sighandler[sig] = osa.sa_handler;
+			}
+		}
+	}
+	if (unmasked) {
+		pselect_notify_setup();
+		pselect_notify_prepare(readfds);
+		nfds = MAX(nfds, notify_pipe[0] + 1);
+	}
+
+	/* Unmask signals, call select then restore signal mask. */
+	sigprocmask(SIG_SETMASK, mask, &osig);
+	ret = select(nfds, readfds, writefds, exceptfds, tvp);
+	saved_errno = errno;
+	sigprocmask(SIG_SETMASK, &osig, NULL);
+
+	if (unmasked)
+		pselect_notify_done(readfds);
+	errno = saved_errno;
+	return ret;
+}
+#endif