From f8e5c55a036f0e2e2a958e30456270f3f9eba933 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 14:52:13 +0200 Subject: Adding upstream version 1.9.5p2. Signed-off-by: Daniel Baumann --- src/tcsetpgrp_nobg.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 src/tcsetpgrp_nobg.c (limited to 'src/tcsetpgrp_nobg.c') diff --git a/src/tcsetpgrp_nobg.c b/src/tcsetpgrp_nobg.c new file mode 100644 index 0000000..bac0aa6 --- /dev/null +++ b/src/tcsetpgrp_nobg.c @@ -0,0 +1,71 @@ +/* + * SPDX-License-Identifier: ISC + * + * Copyright (c) 2017 Todd C. Miller + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +/* + * This is an open source non-commercial project. Dear PVS-Studio, please check it. + * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com + */ + +#include +#include +#include +#include +#include + +#include "sudo.h" + +static volatile sig_atomic_t got_sigttou; + +/* + * SIGTTOU signal handler for tcsetpgrp_nobg() that just sets a flag. + */ +static void +sigttou(int signo) +{ + got_sigttou = 1; +} + +/* + * Like tcsetpgrp() but restarts on EINTR _except_ for SIGTTOU. + * Returns 0 on success or -1 on failure, setting errno. + * Sets got_sigttou on failure if interrupted by SIGTTOU. + */ +int +tcsetpgrp_nobg(int fd, pid_t pgrp_id) +{ + struct sigaction sa, osa; + int rc; + + /* + * If we receive SIGTTOU from tcsetpgrp() it means we are + * not in the foreground process group. + * This avoid a TOCTOU race compared to using tcgetpgrp(). + */ + memset(&sa, 0, sizeof(sa)); + sigemptyset(&sa.sa_mask); + sa.sa_flags = 0; /* do not restart syscalls */ + sa.sa_handler = sigttou; + got_sigttou = 0; + (void)sigaction(SIGTTOU, &sa, &osa); + do { + rc = tcsetpgrp(fd, pgrp_id); + } while (rc != 0 && errno == EINTR && !got_sigttou); + (void)sigaction(SIGTTOU, &osa, NULL); + + return rc; +} -- cgit v1.2.3