[PATCH] nologin: new applet.

[Denys Vlasenko]

On Fri, Nov 4, 2011 at 12:41 PM, Natanael Copa <natanael.copa at gmail.com> wrote:
> Displays a message that an account is not available and
> exits non-zero. It is intended as a replacement shell field
> for accounts that have been disabled.
>
> If the file /etc/nologin.txt exists, displays its contents
> to the user instead of the default message.
>
> login_main                                           -     108    +108
> .rodata                                           101552  101625     +73
> packed_usage                                       23057   23072     +15
> applet_names                                        1882    1890      +8
> applet_main                                         1140    1144      +4
> bbconfig_config_bz2                                 5214    5217      +3
> applet_nameofs                                       570     572      +2
> ------------------------------------------------------------------------------
> (add/remove: 2/0 grow/shrink: 6/0 up/down: 213/0)             Total: 213 bytes
>   text    data     bss     dec     hex filename
>  888199    6311    4712  899222   db896 busybox_old
>  888436    6315    4712  899463   db987 busybox_unstripped
>
> Signed-off-by: Natanael Copa <ncopa at alpinelinux.org>
> ---
>  loginutils/nologin.c |   41 +++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 41 insertions(+), 0 deletions(-)
>  create mode 100644 loginutils/nologin.c
>
> diff --git a/loginutils/nologin.c b/loginutils/nologin.c
> new file mode 100644
> index 0000000..521538e
> --- /dev/null
> +++ b/loginutils/nologin.c
> @@ -0,0 +1,41 @@
> +/* vi: set sw=4 ts=4: */
> +/*
> + * nologin implementation for busybox
> + *
> + * Licensed under GPLv2 or later, see file LICENSE in this source tree.
> + */
> +
> +//config:config NOLOGIN
> +//config:      bool "nologin"
> +//config:      default n
> +//config:      help
> +//config:        displays a message that an account is not available and
> +//config:        exits non-zero. It is intended as a replacement shell field
> +//config:        for accounts that have been disabled.
> +//config:
> +//config:        If the file /etc/nologin.txt exists, displays its contents
> +//config:        to the user instead of the default message.
> +
> +//applet:IF_NOLOGIN(APPLET(nologin, BB_DIR_SBIN, BB_SUID_DROP))
> +//kbuild:lib-$(CONFIG_NOLOGIN) += nologin.o
> +
> +//usage:#define nologin_trivial_usage
> +//usage:       ""
> +//usage:#define nologin_full_usage "\n\n"
> +//usage:       "politely refuse a login\n"
> +
> +#include "libbb.h"
> +#include <syslog.h>
> +
> +int nologin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
> +int nologin_main(int argc UNUSED_PARAM, char **argv)
> +{
> +       int fd;
> +       fd = open("/etc/nologin.txt", O_RDONLY);
> +       if (bb_copyfd_eof(fd, STDOUT_FILENO) == -1)
> +               bb_error_msg_and_die("this account is not available");
> +       if (ENABLE_FEATURE_CLEAN_UP)
> +               close(fd);
> +       return 1;
> +}

Looks like it can be implemented as shell script in fewer bytes.

-- 
vda