Version 8.7release_8_7

* NEWS: Update.
* configure.ac: Raise minor version.
* doc/functions.texi: Document new functions

Include the implementation of the NS resolving MFL functions, as
proposed by Jan Rafaj

* lib/dns.c (ns_lookup): New function.
* lib/dns.h (ns_lookup): New proto.
* mflib/dns.mf4 (hasns): New function.
* src/builtin/dns.bi (primitive_hasns, getns): New functions.

1 files changed, 64 insertions, 36 deletions

diff --git a/doc/functions.texi b/doc/functions.texi
index 75eed904..d25911aa 100644
--- a/doc/functions.texi
+++ b/doc/functions.texi
@@ -5,7 +5,10 @@
 @c Invariant Sections, with the Front and Back-Cover texts at your option. 
 
   This chapter describes library functions available in Mailfromd
-version @value{VERSION}. 
+version @value{VERSION}. For the simplicity of explanation, we use
+the word @samp{boolean} to indicate variables of numeric type that are
+used as boolean values. For such variables, the term @samp{False}
+stands for the numeric 0, and @samp{True} for any non-zero value.
 
 @menu
 * Macro access::
@@ -65,7 +68,7 @@ macro names programmatically, e.g.:
 @end smallexample
 @end deftypefn
 
-@deftypefn {Built-in Function} number macro_defined (string @var{name})
+@deftypefn {Built-in Function} boolean macro_defined (string @var{name})
 Return true if Sendmail macro @var{name} is defined.
 @end deftypefn
 
@@ -602,7 +605,7 @@ is returned otherwise.  In the latter case, the global variable
 @code{ctype_mismatch} is set to the index of the first character that
 is outside of the character class (characters are indexed from 0).
 
-@deftypefn {Built-in Function} number isalnum (string @var{str})
+@deftypefn {Built-in Function} boolean isalnum (string @var{str})
 Checks for alphanumeric characters:
 
 @smallexample
@@ -611,7 +614,7 @@ Checks for alphanumeric characters:
 @end smallexample
 @end deftypefn
 
-@deftypefn {Built-in Function} number isalpha (string @var{str})
+@deftypefn {Built-in Function} boolean isalpha (string @var{str})
 Checks for an alphabetic character:
 
 @smallexample
@@ -620,7 +623,7 @@ Checks for an alphabetic character:
 @end smallexample
 @end deftypefn
 
-@deftypefn {Built-in Function} number isascii (string @var{str})
+@deftypefn {Built-in Function} boolean isascii (string @var{str})
 Checks whether all characters in @var{str} are 7-bit ones, that fit into
 the @acronym{ASCII} character set.
 
@@ -630,47 +633,47 @@ the @acronym{ASCII} character set.
 @end smallexample  
 @end deftypefn
 
-@deftypefn {Built-in Function} number isblank (string @var{str})
+@deftypefn {Built-in Function} boolean isblank (string @var{str})
 Checks if @var{str} contains only blank characters; that is, spaces or
 tabs. 
 @end deftypefn
 
-@deftypefn {Built-in Function} number iscntrl (string @var{str})
+@deftypefn {Built-in Function} boolean iscntrl (string @var{str})
 Checks for control characters.
 @end deftypefn
 
-@deftypefn {Built-in Function} number isdigit (string @var{str})
+@deftypefn {Built-in Function} boolean isdigit (string @var{str})
 Checks for digits (0 through 9).
 @end deftypefn
 
-@deftypefn {Built-in Function} number isgraph (string @var{str})
+@deftypefn {Built-in Function} boolean isgraph (string @var{str})
 Checks for any printable characters except spaces.
 @end deftypefn
 
-@deftypefn {Built-in Function} number islower (string @var{str})
+@deftypefn {Built-in Function} boolean islower (string @var{str})
 Checks for lower-case characters.
 @end deftypefn
 
-@deftypefn {Built-in Function} number isprint (string @var{str})
+@deftypefn {Built-in Function} boolean isprint (string @var{str})
 Checks for printable characters including space.
 @end deftypefn
 
-@deftypefn {Built-in Function} number ispunct (string @var{str})
+@deftypefn {Built-in Function} boolean ispunct (string @var{str})
 Checks for any printable characters which are not a spaces or
 alphanumeric characters.
 @end deftypefn
 
-@deftypefn {Built-in Function} number isspace (string @var{str})
+@deftypefn {Built-in Function} boolean isspace (string @var{str})
 Checks for white-space characters, i.e.: space, form-feed (@samp{\f}),
 newline (@samp{\n}), carriage return (@samp{\r}), horizontal tab
 (@samp{\t}), and vertical tab (@samp{\v}).
 @end deftypefn
 
-@deftypefn {Built-in Function} number isupper (string @var{str})
+@deftypefn {Built-in Function} boolean isupper (string @var{str})
 Checks for uppercase letters. 
 @end deftypefn
 
-@deftypefn {Built-in Function} number isxdigit (string @var{str})
+@deftypefn {Built-in Function} boolean isxdigit (string @var{str})
 Checks for hexadecimal digits, i.e. one of @samp{0}, @samp{1},
 @samp{2}, @samp{3}, @samp{4}, @samp{5}, @samp{6}, @samp{7}, @samp{8},
 @samp{9}, @samp{a}, @samp{b}, @samp{c}, @samp{d}, @samp{e}, @samp{f},
@@ -717,7 +720,7 @@ email address.
 @end deftypefn
 
 @deftypefn {Library Function} boolean email_valid (string @var{email})
-  Returns @var{True} if @var{email} is a valid email address,
+  Returns @samp{True} (1) if @var{email} is a valid email address,
 consisting of local and domain parts only.  E.g.:
 
 @smallexample
@@ -1704,7 +1707,7 @@ compativbility.
   These functions  are defined in the module @file{poll.mf}, which you
 must require prior to using any of them. 
   
-@deftypefn {Library Function} number _pollhost @
+@deftypefn {Library Function} boolean _pollhost @
   (string @var{ip}, string @var{email}, string @var{domain}, @
    string @var{mailfrom})   
   Poll @acronym{SMTP} host @var{ip} for email address @var{email},
@@ -1716,7 +1719,7 @@ main poll tempfails.  The function can throw one of the following
 exceptions: @code{e_failure}, @code{e_temp_failure}.
 @end deftypefn
 
-@deftypefn {Library Function} number _pollmx @
+@deftypefn {Library Function} boolean _pollmx @
   (string @var{ip}, string @var{email}, string @var{domain}, @
    string @var{mailfrom})
   Poll @acronym{MX}s of the @var{domain} for email address @var{email}, using
@@ -1728,7 +1731,7 @@ if the poll fails.  The function can throw one of the following
 exceptions: @code{e_failure}, @code{e_temp_failure}.
 @end deftypefn
 
-@deftypefn {Library Function} number stdpoll @
+@deftypefn {Library Function} boolean stdpoll @
   (string @var{email}, string @var{domain}, string @var{mailfrom})
   
   Performs standard poll for @var{email}, using @var{domain} as
@@ -1740,7 +1743,7 @@ the following exceptions: @code{e_failure}, @code{e_temp_failure}.
 without explicit @var{host}.  @FIXME{more details and references.}
 @end deftypefn
 
-@deftypefn {Library Function} number strictpoll @
+@deftypefn {Library Function} boolean strictpoll @
   (string @var{host}, string @var{email}, @
    string @var{domain}, string @var{mailfrom})
 
@@ -1925,7 +1928,7 @@ records) for the @acronym{IP}v4 address @var{ipstr}.
 @end deftypefn
 
 @deftypefn {Built-in Function} string getmx (string @var{domain} @
-  [, number @var{ip}])
+  [, boolean @var{ip}])
   Returns a whitespace-separated list of @samp{MX} names (if @var{ip} is not
 given or if it is @code{0}) or @samp{MX} @acronym{IP} addresses (if
 @code{@var{ip}!=0})) for @var{domain}.  Within the returned
@@ -2114,6 +2117,30 @@ record are compared against @var{ip}.  The function returns true if a
 matching A record is found.
 @end deftypefn
 
+@deftypefn {Built-in Function} boolean primitive_hasns (string @var{domain})
+Returns @samp{True} if the domain @var{domain} has at least one
+@samp{NS} record. Throws exception if DNS lookup fails.
+@end deftypefn
+
+@deftypefn {Library Function} boolean hasns (string @var{domain})
+Returns @samp{True} if the domain @var{domain} has at least one
+@samp{NS} record. Returns @samp{False} if there are no @samp{NS}
+records or if the DNS lookup fails.
+@end deftypefn
+
+@deftypefn {Built-in Function} string getns (string @var{domain} ; @
+                                 boolean @var{resolve}, boolean @var{sort})
+  Returns a whitespace-separated list of all the @samp{NS} records for
+the domain @var{domain}. Optional parameters @var{resolve} and
+@var{sort} control the formatting. If @var{resolve} is 0 (the default), the
+resulting string will contain IP addresses of the NS servers. If
+@var{resolve} is not 0, hostnames will be returned instead. If
+@var{sort} is 1, the returned items will be sorted.
+
+If the @acronym{DNS} query fails, @code{getns} raises an appropriate
+exception.
+@end deftypefn
+
 @node Geolocation functions
 @section Geolocation functions
 @cindex geolocation
@@ -2249,7 +2276,7 @@ argument to the database functions (in description below, marked as
 
 @anchor{dbmap}
 @deftypefn {Built-in Function} boolean dbmap (string @var{db}, @
-    string @var{key}, [number @var{null}])
+    string @var{key}, [boolean @var{null}])
   Looks up @var{key} in the @acronym{DBM} file @var{db} and returns
 @code{true} if it is found.
 
@@ -2259,7 +2286,7 @@ argument to the database functions (in description below, marked as
 @end deftypefn
 
 @deftypefn {Built-in Function} string dbget (string @var{db}, @
-  string @var{key} [, string @var{default}, number @var{null}])
+  string @var{key} [, string @var{default}, boolean @var{null}])
   Looks up @var{key} in the database @var{db} and returns the value
 associated with it.  If the key is not found returns @var{default}, if
 specified, or empty string otherwise.
@@ -2269,7 +2296,7 @@ specified, or empty string otherwise.
 
 @deftypefn {Built-in Function} void dbput (string @var{db}, @
  string @var{key}, string @var{value} [, @
- number @var{null}, number @var{mode} ])
+ boolean @var{null}, number @var{mode} ])
   Inserts in the database a record with the given @var{key} and
 @var{value}.  If a record with the given @var{key} already exists, its
 value is replaced with the supplied one.
@@ -2281,7 +2308,7 @@ to explicitly specify the file mode for this database.  See also
 
 @deftypefn {Built-in Function} void dbinsert (string @var{db}, @
  string @var{key}, string @var{value} [, @
- number @var{replace}, number @var{null}, number @var{mode} ])
+ boolean @var{replace}, boolean @var{null}, number @var{mode} ])
   This is an improved variant of @code{dbput}, which provides a
 better control on the actions to take if the @var{key} already exists in the
 database.  Namely, if @var{replace} is @samp{True}, the old value is
@@ -2290,7 +2317,7 @@ is thrown.
 @end deftypefn
  
 @deftypefn {Built-in Function} void dbdel (string @var{db}, @
- string @var{key} [, number @var{null}, number @var{mode}])
+ string @var{key} [, boolean @var{null}, number @var{mode}])
   Delete from the database the record with the given @var{key}.  If
 there are no such record, return without signalling error.
 
@@ -2313,7 +2340,7 @@ require safedb
 The exception-safe interfaces are:
 
 @deftypefn {Library Function} string safedbmap (string @var{db}, @
-  string @var{key} [, string @var{default}, number @var{null}])
+  string @var{key} [, string @var{default}, boolean @var{null}])
 
   This is an exception-safe interface to @code{dbmap}.  If a
 database error occurs while attempting to retrieve the record,
@@ -2322,7 +2349,7 @@ not defined.
 @end deftypefn
 
 @deftypefn {Library Function} string safedbget (string @var{db}, @
-  string @var{key} [, string @var{default}, number @var{null}])
+  string @var{key} [, string @var{default}, boolean @var{null}])
 
   This is an exception-safe interface to @code{dbget}.  If a
 database error occurs while attempting to retrieve the record,
@@ -2331,7 +2358,7 @@ not defined.
 @end deftypefn
 
 @deftypefn {Library Function} void safedbput (string @var{db}, @
- string @var{key}, string @var{value} [, number @var{null}])
+ string @var{key}, string @var{value} [, boolean @var{null}])
  
   This is an exception-safe interface to @code{dbput}.  If a
 database error occurs while attempting to retrieve the record,
@@ -2339,7 +2366,7 @@ the function returns without raising exception.
 @end deftypefn
 
 @deftypefn {Library Function} void safedbdel (string @var{db}, @
- string @var{key} [, number @var{null}])
+ string @var{key} [, boolean @var{null}])
  
   This is an exception-safe interface to @code{dbdel}.  If a
 database error occurs while attempting to delete the record,
@@ -2422,8 +2449,9 @@ is currently enabled.  If @var{fmtid} does not match any known format,
 
 @cindex disabling cache
 @cindex cache, disabling
-@deftypefn {Built-in Function} void db_set_active (string @var{fmtid}, number @var{enable})
-  Enables the cache database @var{fmtid} if @var{enable} is not null,
+@deftypefn {Built-in Function} void db_set_active (string @var{fmtid}, @
+                                         boolean @var{enable})
+  Enables the cache database @var{fmtid} if @var{enable} is @samp{True},
 or disables it otherwise.  For example, to disable @acronym{DNS}
 caching, do:
 
@@ -2784,12 +2812,12 @@ The function @code{revip} is defined in @ref{revip}.
 @node System functions
 @section System functions
 
-@deftypefn {Built-in Function} number access (string @var{pathname}, @
+@deftypefn {Built-in Function} boolean access (string @var{pathname}, @
   number @var{mode})
 Checks whether the calling process can access the file @var{pathname}.
 If @var{pathname} is a symbolic link, it is dereferenced.  The
-function returns 1 (@samp{true}) if the file can be accessed and 0
-(@samp{false}) otherwise@footnote{@emph{Note}, that the return code is
+function returns @samp{True} if the file can be accessed and
+@samp{False} otherwise@footnote{@emph{Note}, that the return code is 
 inverted in respect to the system function @samp{access(2)}.}.
 
 Symbolic values for @var{mode} are provided in module
@@ -4833,7 +4861,7 @@ debug_level("db") @result{} 0
 @end smallexample
 @end deftypefn
 
-@deftypefn {Built-in Function} number callout_transcript ([number @var{value}])
+@deftypefn {Built-in Function} boolean callout_transcript ([boolean @var{value}])
 Returns the current state of the callout SMTP transcript.  The result
 is 1 if the transcript is enabled and 0 otherwise.  The transcript is
 normally enabled either by the use of the @option{--transcript}