At exit, restore stdin and stdout to blocking.

Test: run_init id && run_init id
Test: open_init_pty bash -c 'echo hello; exec >&- 2>&- <&-; sleep 1;'

Fixes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=863187
Fixes: https://bugs.gentoo.org/show_bug.cgi?id=621062
Signed-off-by: Stephen Smalley <[email protected]>
---
 policycoreutils/run_init/open_init_pty.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/policycoreutils/run_init/open_init_pty.c 
b/policycoreutils/run_init/open_init_pty.c
index 6e25ea3..150cb45 100644
--- a/policycoreutils/run_init/open_init_pty.c
+++ b/policycoreutils/run_init/open_init_pty.c
@@ -191,6 +191,28 @@ static void setfd_nonblock(int fd)
        }
 }
 
+static void setfd_block(int fd)
+{
+       int fsflags = fcntl(fd, F_GETFL);
+
+       if (fsflags < 0) {
+               fprintf(stderr, "fcntl(%d, F_GETFL): %s\n", fd, 
strerror(errno));
+               exit(EX_IOERR);
+       }
+
+       if (fcntl(fd, F_SETFL, fsflags & ~O_NONBLOCK) < 0) {
+               fprintf(stderr, "fcntl(%d, F_SETFL, ... & ~O_NONBLOCK): %s\n", 
fd, strerror(errno));
+               exit(EX_IOERR);
+       }
+}
+
+static void setfd_atexit(void)
+{
+       setfd_block(STDIN_FILENO);
+       setfd_block(STDOUT_FILENO);
+       return;
+}
+
 static void sigchld_handler(int asig __attribute__ ((unused)))
 {
 }
@@ -280,6 +302,10 @@ int main(int argc, char *argv[])
        setfd_nonblock(pty_master);
        setfd_nonblock(STDIN_FILENO);
        setfd_nonblock(STDOUT_FILENO);
+       if (atexit(setfd_atexit) < 0) {
+               perror("atexit()");
+               exit(EXIT_FAILURE);
+       }
 
        if (isatty(STDIN_FILENO)) {
                if (tty_semi_raw(STDIN_FILENO) < 0) {
-- 
2.9.4

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