[systemd-devel] [PATCH] [PATCH v2] nspawn: fallback on bind mount when mknod fails

[Lennart Poettering]

On Tue, 31.03.15 16:51, Alban Crequy (alban.crequy at gmail.com) wrote:

> -                        if (mknod(to, st.st_mode, st.st_rdev) < 0)
> -                                return log_error_errno(errno, "mknod(%s) failed: %m", to);
> +                        if (mknod(to, st.st_mode, st.st_rdev) < 0) {
> +                                if (errno != EPERM)
> +                                        return log_error_errno(errno, "mknod(%s) failed: %m", to);
> +
> +                                /* Some systems abusively restrict mknod but
> +                                 * allow bind mounts. */
> +                                if (touch(to) < 0)
> +                                        return
> -                                log_error_errno(errno, "touch (%s)
> -                                failed: %m", to);

touch() is our call, please use its return code for showing the error,
not errno.

For our own calls we exclusively use kernel-style error handling by
returning -errno, while not making any guarantees on errno being
set. Hence: whenever you invoke a naked syscall, use errno, if you use
one of our own calls use the negative return code.

> +                                if (mount(from, to, NULL, MS_BIND, NULL) < 0)
> +                                        return log_error_errno(errno, "both mknod and bind mount (%s) failed: %m", to);

Nitpick: Could you uppercase the "B" in "both", please? It's the
beginning of a sentence, and not a syscall name or so...


> -        if (mknod(to, (st.st_mode & ~07777) | 0600, st.st_rdev) < 0)
> -                return log_error_errno(errno, "mknod() for /dev/console failed: %m");
> +        if (touch(to) < 0)
> +                return log_error_errno(errno, "touch() for
> -                /dev/console failed: %m");

Same here, as above.

Lennart

-- 
Lennart Poettering, Red Hat