upstream: convert select() to poll() ok djm

OpenBSD-Commit-ID: b53e4940ff10dd24f8d16e8db8ef1970015d7ead

1 files changed, 16 insertions, 22 deletions

diff --git a/sftp-server.c b/sftp-server.c
index 3f35c399a..3f3de399d 100644
--- a/sftp-server.c
+++ b/sftp-server.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-server.c,v 1.131 2021/11/08 21:32:49 djm Exp $ */
+/* $OpenBSD: sftp-server.c,v 1.132 2021/11/14 03:25:10 deraadt Exp $ */
 /*
  * Copyright (c) 2000-2004 Markus Friedl.  All rights reserved.
  *
@@ -33,6 +33,7 @@
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <poll.h>
 #include <pwd.h>
 #include <stdlib.h>
 #include <stdio.h>
@@ -1708,9 +1709,8 @@ sftp_server_usage(void)
 int
 sftp_server_main(int argc, char **argv, struct passwd *user_pw)
 {
-	fd_set *rset, *wset;
-	int i, r, in, out, max, ch, skipargs = 0, log_stderr = 0;
-	ssize_t len, olen, set_size;
+	int i, r, in, out, ch, skipargs = 0, log_stderr = 0;
+	ssize_t len, olen;
 	SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
 	char *cp, *homedir = NULL, uidstr[32], buf[4*4096];
 	long mask;
@@ -1827,20 +1827,11 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
 	setmode(out, O_BINARY);
 #endif
 
-	max = 0;
-	if (in > max)
-		max = in;
-	if (out > max)
-		max = out;
-
 	if ((iqueue = sshbuf_new()) == NULL)
 		fatal_f("sshbuf_new failed");
 	if ((oqueue = sshbuf_new()) == NULL)
 		fatal_f("sshbuf_new failed");
 
-	rset = xcalloc(howmany(max + 1, NFDBITS), sizeof(fd_mask));
-	wset = xcalloc(howmany(max + 1, NFDBITS), sizeof(fd_mask));
-
 	if (homedir != NULL) {
 		if (chdir(homedir) != 0) {
 			error("chdir to \"%s\" failed: %s", homedir,
@@ -1848,10 +1839,13 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
 		}
 	}
 
-	set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
 	for (;;) {
-		memset(rset, 0, set_size);
-		memset(wset, 0, set_size);
+		struct pollfd pfd[2];
+
+		memset(pfd, 0, sizeof pfd);
+		pfd[0].fd = pfd[1].fd = -1;
+		pfd[0].events = POLLIN;
+		pfd[1].events = POLLOUT;
 
 		/*
 		 * Ensure that we can read a full buffer and handle
@@ -1861,23 +1855,23 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
 		if ((r = sshbuf_check_reserve(iqueue, sizeof(buf))) == 0 &&
 		    (r = sshbuf_check_reserve(oqueue,
 		    SFTP_MAX_MSG_LENGTH)) == 0)
-			FD_SET(in, rset);
+			pfd[0].fd = in;
 		else if (r != SSH_ERR_NO_BUFFER_SPACE)
 			fatal_fr(r, "reserve");
 
 		olen = sshbuf_len(oqueue);
 		if (olen > 0)
-			FD_SET(out, wset);
+			pfd[1].fd = out;
 
-		if (select(max+1, rset, wset, NULL, NULL) == -1) {
+		if (poll(pfd, 2, -1) == -1) {
 			if (errno == EINTR)
 				continue;
-			error("select: %s", strerror(errno));
+			error("poll: %s", strerror(errno));
 			sftp_server_cleanup_exit(2);
 		}
 
 		/* copy stdin to iqueue */
-		if (FD_ISSET(in, rset)) {
+		if (pfd[0].revents & POLLIN) {
 			len = read(in, buf, sizeof buf);
 			if (len == 0) {
 				debug("read eof");
@@ -1889,7 +1883,7 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
 				fatal_fr(r, "sshbuf_put");
 		}
 		/* send oqueue to stdout */
-		if (FD_ISSET(out, wset)) {
+		if (pfd[1].revents & POLLOUT) {
 			len = write(out, sshbuf_ptr(oqueue), olen);
 			if (len == -1) {
 				error("write: %s", strerror(errno));