diff options
Diffstat (limited to 'src/basic/hostname-util.c')
| -rw-r--r-- | src/basic/hostname-util.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/src/basic/hostname-util.c b/src/basic/hostname-util.c index e336f269fa..21fae89fd0 100644 --- a/src/basic/hostname-util.c +++ b/src/basic/hostname-util.c @@ -61,14 +61,22 @@ static bool hostname_valid_char(char c) { 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 + * relax is true and at least two components are present in the name. + */ +bool hostname_is_valid(const char *s, bool relax) { const char *p; bool dot; + unsigned dots = 0; 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. */ @@ -79,6 +87,7 @@ bool hostname_is_valid(const char *s) { return false; dot = true; + dots ++; } else { if (!hostname_valid_char(*p)) return false; @@ -87,7 +96,7 @@ bool hostname_is_valid(const char *s) { } } - if (dot) + if (dot && (dots < 2 || !relax)) return false; if (p-s > HOST_NAME_MAX) |