[PATCH] newrole: fix for newrole hanging on some serial consoles

[Linda Knippers <linda.knippers@hp.com>]

The following patch addresses a problem I experienced with newrole hanging
when run from a serial console when the console is configured using the
default /etc/inittab settings.  newrole would hang when re-opening the
tty device.  This patch causes newrole to mimic the behavior of agetty,
which opens the device with O_NONBLOCK and then turns the bit off before
execing the next program.  Changing /etc/inittab to use the -L option for
agetty will avoid the problem but that solution won't be obvious to anyone
experiencing the problem and it may introduce other issues.

This patch was tested with policycoreutils-newrole-1.33.12-5.el5 on RHEL5 RC1.

-- ljk


--- newrole.c   2007-02-20 13:32:46.000000000 -0500
+++ newrole.c.ljk2      2007-02-20 13:32:39.000000000 -0500
@@ -636,11 +636,12 @@ static int relabel_tty(const char *ttyn,
        }

        /* Re-open TTY descriptor */
-       fd = open(ttyn, O_RDWR);
+       fd = open(ttyn, O_RDWR|O_NONBLOCK);
        if (fd < 0) {
                fprintf(stderr, _("Error!  Could not open %s.\n"), ttyn);
                return fd;
        }
+       fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NONBLOCK);

        if (fgetfilecon(fd, &tty_con) < 0) {
                fprintf(stderr, _("%s!  Could not get current context "
@@ -1127,15 +1128,18 @@ int main(int argc, char *argv[])
                fprintf(stderr, _("Could not close descriptors.\n"));
                goto err_close_pam;
        }
-       fd = open(ttyn, O_RDONLY);
+       fd = open(ttyn, O_RDONLY|O_NONBLOCK);
        if (fd != 0)
                goto err_close_pam;
-       fd = open(ttyn, O_RDWR);
+       fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NONBLOCK);
+       fd = open(ttyn, O_RDWR|O_NONBLOCK);
        if (fd != 1)
                goto err_close_pam;
-       fd = open(ttyn, O_RDWR);
+       fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NONBLOCK);
+       fd = open(ttyn, O_RDWR|O_NONBLOCK);
        if (fd != 2)
                goto err_close_pam;
+       fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NONBLOCK);

        /*
         * Step 5:  Execute a new shell with the new context in `new_context'.


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