c == '.';
}
-bool hostname_is_valid(const char *s) {
+/**
+ * Check if s looks like a valid host name or FQDN. This does not do
+ * full DNS validation, but only checks if the name is composed of
+ * allowed characters and the length is not above the maximum allowed
+ * by Linux (c.f. dns_name_is_valid()). Trailing dot is allowed if
+ * allow_trailing_dot is true and at least two components are present
+ * in the name. Note that due to the restricted charset and length
+ * this call is substantially more conservative than
+ * dns_domain_is_valid().
+ */
+bool hostname_is_valid(const char *s, bool allow_trailing_dot) {
+ unsigned n_dots = 0;
const char *p;
bool dot;
if (isempty(s))
return false;
- /* Doesn't accept empty hostnames, hostnames with trailing or
+ /* Doesn't accept empty hostnames, hostnames with
* leading dots, and hostnames with multiple dots in a
* sequence. Also ensures that the length stays below
* HOST_NAME_MAX. */
return false;
dot = true;
+ n_dots ++;
} else {
if (!hostname_valid_char(*p))
return false;
}
}
- if (dot)
+ if (dot && (n_dots < 2 || !allow_trailing_dot))
return false;
- if (p-s > HOST_NAME_MAX)
+ if (p-s > HOST_NAME_MAX) /* Note that HOST_NAME_MAX is 64 on
+ * Linux, but DNS allows domain names
+ * up to 255 characters */
return false;
return true;
}
-char* hostname_cleanup(char *s, bool lowercase) {
+char* hostname_cleanup(char *s) {
char *p, *d;
bool dot;
*(d++) = '.';
dot = true;
} else if (hostname_valid_char(*p)) {
- *(d++) = lowercase ? tolower(*p) : *p;
+ *(d++) = *p;
dot = false;
}
/* This tries to identify local host and domain names
* described in RFC6761 plus the redhatism of .localdomain */
- return streq(hostname, "localhost") ||
- streq(hostname, "localhost.") ||
- streq(hostname, "localdomain.") ||
- streq(hostname, "localdomain") ||
- endswith(hostname, ".localhost") ||
- endswith(hostname, ".localhost.") ||
- endswith(hostname, ".localdomain") ||
- endswith(hostname, ".localdomain.");
+ return strcaseeq(hostname, "localhost") ||
+ strcaseeq(hostname, "localhost.") ||
+ strcaseeq(hostname, "localdomain.") ||
+ strcaseeq(hostname, "localdomain") ||
+ endswith_no_case(hostname, ".localhost") ||
+ endswith_no_case(hostname, ".localhost.") ||
+ endswith_no_case(hostname, ".localdomain") ||
+ endswith_no_case(hostname, ".localdomain.");
}
/// UNNEEDED by elogind
#if 0
+bool is_gateway_hostname(const char *hostname) {
+ assert(hostname);
+
+ /* This tries to identify the valid syntaxes for the our
+ * synthetic "gateway" host. */
+
+ return
+ strcaseeq(hostname, "gateway") ||
+ strcaseeq(hostname, "gateway.");
+}
+
int sethostname_idempotent(const char *s) {
char buf[HOST_NAME_MAX + 1] = {};
truncate_nl(l);
if (l[0] != '\0' && l[0] != '#') {
/* found line with value */
- name = hostname_cleanup(l, false);
+ name = hostname_cleanup(l);
name = strdup(name);
if (!name)
return -ENOMEM;