[systemd-devel] [PATCH v2] hostname: Allow comments in /etc/hostname

[Lennart Poettering]

On Mon, 18.05.15 12:36, Martin Pitt (martin.pitt at ubuntu.com) wrote:

>  static int read_and_strip_hostname(const char *path, char **hn) {
> -        char *s;
> -        int r;
> +        _cleanup_fclose_ FILE *f = NULL;
> +        char l[LINE_MAX];
> +        char *s = NULL;
>  
>          assert(path);
>          assert(hn);
>  
> -        r = read_one_line_file(path, &s);
> -        if (r < 0)
> -                return r;
> +        /* may have comments, ignore them */
> +        f = fopen("/etc/hostname", "re");
> +        if (!f)
> +                return -errno;
> +        FOREACH_LINE(l, f, return -errno) {
> +                truncate_nl(l);
> +                if (l[0] != '\0' && l[0] != '#') {
> +                        s = strdup(l);
> +                        break;

This code will result in ENOENT being returned on OOM... That's not right...

Also consider using strstrip() here.

> -        r = read_one_line_file("/etc/hostname", &c->data[PROP_STATIC_HOSTNAME]);
> -        if (r < 0 && r != -ENOENT)
> -                return r;
> +        /* /etc/hostname may have comments, ignore them */
> +        f = fopen("/etc/hostname", "re");
> +        if (!f)
> +                return -errno;
> +        FOREACH_LINE(l, f, return -errno) {
> +                truncate_nl(l);
> +                if (l[0] != '\0' && l[0] != '#') {
> +                        c->data[PROP_STATIC_HOSTNAME] = strdup(l);
> +                        break;
> +                }
> +        }

Given that this same code is needed twice in different components,
please add a new call read_etc_hostname() to
src/shared/hostname-util.c (which I just added to git). It should then
also do hostname_cleanup() on the name, and thus pretty much replace
read_and_strip_hostname() entirely in hostname-setup.c.

Lennart

-- 
Lennart Poettering, Red Hat