Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit e34577ce authored by Nick Kralevich's avatar Nick Kralevich
Browse files

init: use SELinux /dev/null if available 

SELinux provides it's own /dev/null character device at
/sys/fs/selinux/null. This character device is exactly the same
as /dev/null, including the same major/minor numbers, and can
be used wherever /dev/null is used.

Use /sys/fs/selinux/null instead of trying to create our own
/dev/__null__ device. This moves us one step closer to eliminating
all uses of mknod() by init.

/sys/fs/selinux/null is only available once the /sys/fs/selinux filesystem
is mounted. It's not available to the first stage init, so we
still have to fall back to mknod then.

Change-Id: Ic733767ea6220a130537de33cc478ae79578ce20
parent 178299fd

init/util.cpp

+19 −14
Original line number Original line Diff line number Diff line
@@ -379,23 +379,28 @@ int wait_for_file(const char *filename, int timeout) 




void open_devnull_stdio(void)

void open_devnull_stdio(void)

{

{

    int fd;

    // Try to avoid the mknod() call if we can. Since SELinux makes

    // a /dev/null replacement available for free, let's use it.

    int fd = open("/sys/fs/selinux/null", O_RDWR);

    if (fd == -1) {

        // OOPS, /sys/fs/selinux/null isn't available, likely because

        // /sys/fs/selinux isn't mounted. Fall back to mknod.

        static const char *name = "/dev/__null__";

        static const char *name = "/dev/__null__";

        if (mknod(name, S_IFCHR | 0600, (1 << 8) | 3) == 0) {

        if (mknod(name, S_IFCHR | 0600, (1 << 8) | 3) == 0) {

            fd = open(name, O_RDWR);

            fd = open(name, O_RDWR);

            unlink(name);

            unlink(name);

        if (fd >= 0) {

        }

        if (fd == -1) {

            exit(1);

        }

    }



    dup2(fd, 0);

    dup2(fd, 0);

    dup2(fd, 1);

    dup2(fd, 1);

    dup2(fd, 2);

    dup2(fd, 2);

    if (fd > 2) {

    if (fd > 2) {

        close(fd);

        close(fd);

    }

    }

            return;

        }

    }



    exit(1);

}

}





void import_kernel_cmdline(int in_qemu,

void import_kernel_cmdline(int in_qemu,