src/lib/hostpid.c

/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "hostpid.h"

#include <unistd.h>
#include <netdb.h>

#define HOSTNAME_DISALLOWED_CHARS "/\r\n\t"

const char *my_hostname = NULL;
const char *my_pid = NULL;

static char *my_hostname_dup = NULL;
static char *my_domain = NULL;

void hostpid_init(void)
{
    static char pid[MAX_INT_STRLEN];
    char hostname[256];
    const char *value;

    /* allow calling hostpid_init() multiple times to reset hostname */
    i_free_and_null(my_hostname_dup);
    i_free_and_null(my_domain);

    value = getenv(MY_HOSTNAME_ENV);
    if (value == NULL) {
        if (gethostname(hostname, sizeof(hostname)-1) < 0)
            i_fatal("gethostname() failed: %m");
        hostname[sizeof(hostname)-1] = '\0';
        value = hostname;
    }

    if (value[0] == '\0' ||
        strcspn(value, HOSTNAME_DISALLOWED_CHARS) != strlen(value))
        i_fatal("Invalid system hostname: '%s'", value);
    my_hostname_dup = i_strdup(value);
    my_hostname = my_hostname_dup;

    i_snprintf(pid, sizeof(pid), "%lld", (long long)getpid());
    my_pid = pid;
}

void hostpid_deinit(void)
{
    i_free(my_hostname_dup);
    i_free(my_domain);
}

const char *my_hostdomain(void)
{
    struct hostent *hent;
    const char *name;

    if (my_domain == NULL) {
        name = getenv(MY_HOSTDOMAIN_ENV);
        if (name == NULL) {
            hent = gethostbyname(my_hostname);
            name = hent != NULL ? hent->h_name : NULL;
            if (name == NULL) {
                /* failed, use just the hostname */
                name = my_hostname;
            }
        }
        my_domain = i_strdup(name);
    }
    return my_domain;
}