script: make it work even if fd 0 is closed

Testcase:
script -q -c "echo hey" /dev/null 0>&-

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 8 insertions, 1 deletions

diff --git a/libbb/getpty.c b/libbb/getpty.c
index 435e4d09f..391d729f2 100644
--- a/libbb/getpty.c
+++ b/libbb/getpty.c
@@ -16,7 +16,7 @@ int FAST_FUNC xgetpty(char *line)
 
 #if ENABLE_FEATURE_DEVPTS
         p = open("/dev/ptmx", O_RDWR);
-        if (p > 0) {
+        if (p >= 0) {
                 grantpt(p); /* chmod+chown corresponding slave pty */
                 unlockpt(p); /* (what does this do?) */
 # ifndef HAVE_PTSNAME_R
diff --git a/util-linux/script.c b/util-linux/script.c
index 8fb991d15..abcd73bff 100644
--- a/util-linux/script.c
+++ b/util-linux/script.c
@@ -77,8 +77,15 @@ int script_main(int argc UNUSED_PARAM, char **argv)
         if (!(opt & OPT_q)) {
                 printf("Script started, file is %s\n", fname);
         }
+
         shell = get_shell_name();
 
+        /* Some people run "script ... 0>&-".
+         * Our code assumes that STDIN_FILENO != pty.
+         * Ensure STDIN_FILENO is not closed:
+         */
+        bb_sanitize_stdio();
+
         pty = xgetpty(pty_line);
 
         /* get current stdin's tty params */