mesg: use only stat() to get the current terminal status

open()+stat() does not work for example after su(1) (from root to
non-root). It seems better to use only stat() to get the current
terminal status.

Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1906157
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/term-utils/mesg.c b/term-utils/mesg.c
index 56fb70094668879ff328b1984e85f3f64d6889aa..cb0b493d3fc2de19eedfd89e714b3fcce7fdbfcd 100644 (file)
--- a/term-utils/mesg.c
+++ b/term-utils/mesg.c
@@ -139,13 +139,9 @@ int main(int argc, char *argv[])
                        warnx(_("ttyname() failed, attempting to go around using: %s"), tty);
        }
 
-       if ((fd = open(tty, O_RDONLY)) < 0)
-               err(MESG_EXIT_FAILURE, _("cannot open %s"), tty);
-       if (fstat(fd, &sb))
-               err(MESG_EXIT_FAILURE, _("stat of %s failed"), tty);
-
        if (!*argv) {
-               close(fd);
+               if (stat(tty, &sb))
+                       err(MESG_EXIT_FAILURE, _("stat of %s failed"), tty);
                if (sb.st_mode & (S_IWGRP | S_IWOTH)) {
                        puts(_("is y"));
                        return IS_ALLOWED;
@@ -154,6 +150,11 @@ int main(int argc, char *argv[])
                return IS_NOT_ALLOWED;
        }
 
+       if ((fd = open(tty, O_RDONLY)) < 0)
+               err(MESG_EXIT_FAILURE, _("cannot open %s"), tty);
+       if (fstat(fd, &sb))
+               err(MESG_EXIT_FAILURE, _("stat of %s failed"), tty);
+
        switch (rpmatch(argv[0])) {
        case RPMATCH_YES:
 #ifdef USE_TTY_GROUP