systemd/hostname-setup.c

/*-*- Mode: C; c-basic-offset: 8 -*-*/

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>

#include "hostname-setup.h"
#include "macro.h"
#include "util.h"
#include "log.h"

#define LINE_MAX 4096

static int read_hostname(char **hn) {

#if defined(TARGET_FEDORA)
        int r;
        FILE *f;

        assert(hn);

        if (!(f = fopen("/etc/sysconfig/network", "re")))
                return -errno;

        for (;;) {
                char line[LINE_MAX];
                char *s, *k;

                if (!fgets(line, sizeof(line), f)) {
                        if (feof(f))
                                break;

                        r = -errno;
                        goto finish;
                }

                s = strstrip(line);

                if (!startswith(s, "HOSTNAME="))
                        continue;

                if (!(k = strdup(s+9))) {
                        r = -ENOMEM;
                        goto finish;
                }

                *hn = k;
                break;
        }

        r = 0;

finish:
        fclose(f);
        return r;

#elif defined(TARGET_SUSE)
        int r;
        char *s, *k;

        assert(hn);

        if ((r = read_one_line_file("/etc/HOSTNAME", &s)) < 0)
                return r;

        k = strdup(strstrip(s));
        free(s);

        if (!k)
                return -ENOMEM;

        *hn = k;

#elif defined(TARGET_DEBIAN)
        int r;
        char *s, *k;

        assert(hn);

        if ((r = read_one_line_file("/etc/hostname", &s)) < 0)
                return r;

        k = strdup(strstrip(s));
        free(s);

        if (!k)
                return -ENOMEM;

        *hn = k;
#else
#warning "Don't know how to read the hostname"

        return -ENOENT;
#endif

        return 0;
}

int hostname_setup(void) {
        int r;
        char *hn;

        if ((r = read_hostname(&hn)) < 0) {
                if (r != -ENOENT)
                        log_warning("Failed to read configured hostname: %s", strerror(-r));

                return r;
        }

        r = sethostname(hn, strlen(hn)) < 0 ? -errno : 0;

        if (r < 0)
                log_warning("Failed to set hostname to <%s>: %s", hn, strerror(-r));
        else
                log_info("Set hostname to <%s>.", hn);

        free(hn);

        return r;
}