Implement some system information functions.

* mfd/bi_gethostname.m4: New file.
* NEWS, doc/mailfromd.texi: Update.
* mfd/Makefile.am (M4_FILES): Add bi_gethostname.m4.
* mfd/bi_system.m4 (uname): New function.
* mfd/prog.c (heap_obstack_cancel, heap_obstack_base): New function.
* mfd/prog.h: Likewise.
* mfd/snarf.m4 (MF_OBSTACK_BASE, MF_OBSTACK_CANCEL): New defuns.
* mtasim/mtasim.c (stop_mailfromd): Reset signal handler before
doing kill, so that waitpid works on hosts with BSD signal semantics.

9 files changed, 279 insertions, 8 deletions

diff --git a/NEWS b/NEWS
index c79dfa7d..b50d87a8 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,4 @@
-Mailfromd NEWS -- history of user-visible changes. 2009-05-09
+Mailfromd NEWS -- history of user-visible changes. 2009-05-10
 Copyright (C) 2005, 2006, 2007, 2008, 2009 Sergey Poznyakoff
 See the end of file for copying conditions.
 
@@ -60,6 +60,20 @@ Index is 1-based.
 All current_header functions raise the e_not_found exception if the
 requested header is not found.
 
+New system information functions are added:
+
+- string gethostname ()
+
+Return the host name of this machine.
+
+- string getdomainname ()
+
+Return the domain name of this machine.
+
+- string uname (string format)
+
+Return system information formatted according to the format specification.
+
 * New pragma `dbprop'
 
 This pragma defines user database properties.  It takes two or three
diff --git a/doc/mailfromd.texi b/doc/mailfromd.texi
index 0d171ab0..3d2e43c5 100644
--- a/doc/mailfromd.texi
+++ b/doc/mailfromd.texi
@@ -7728,6 +7728,20 @@ The function @code{revip} is defined in @ref{revip}.
 @node System functions
 @subsubsection System functions
 
+@deftypefn {Built-in Function} string gethostname ()
+Return the host name of this machine.
+@end deftypefn
+
+@deftypefn {Built-in Function} string getdomainname ()
+Return the domain name of this machine.   Note, that it does not
+necessarily coincide with the actual machine name in @acronym{DNS}.
+
+Depending on the underlying @samp{libc} implementation, this call may
+return empty string or the string @samp{(none)}.  Do not rely on it to
+get the real hostname of the box @command{mailfromd} runs on, use
+@acronym{DNS} functions instead.
+@end deftypefn
+
 @deftypefn {Built-in Function} number time ()
   Return the time since the Epoch (00:00:00 UTC, January 1, 1970),
 measured in seconds. 
@@ -7763,6 +7777,43 @@ strftime('%Y-%m-%d %H:%M:%S %Z', 1164477564, 1)
 @end smallexample
 @end deftypefn
 
+@deftypefn {Built-in Function} uname (string @var{format})
+This function returns system information formatted according to
+the format specification @var{format}.   Ordinary characters placed
+in the format string are copied to the output without conversion.
+Conversion specifiers are introduced by a @samp{%} character.
+The following conversions are defined:
+
+@table @asis
+@item %s
+Name of this system.
+
+@item %n
+Name of this node within the communications network to which this node
+is attached.  Note, that it does not necessarily coincide with the
+actual machine name in @acronym{DNS}. 
+
+@item %r
+Kernel release.
+
+@item %v
+Kernel version.
+
+@item %m
+Name of the hardware type on which the system is running.
+@end table
+
+For example:
+
+@smallexample
+  uname('%n runs %s, release %r on %m')
+    @result{} "Trurl runs Linux, release 2.6.26 on i686"
+@end smallexample
+
+Notice the use of single quotes.
+
+@end deftypefn
+
 @deftypefn {Built-in Function} number system (string @var{str})
   The function @code{system} executes a command specified in @var{str}
 by calling @command{/bin/sh -c string}, and returns -1 on error or
diff --git a/mfd/Makefile.am b/mfd/Makefile.am
index 03c2fca3..a22c20f4 100644
--- a/mfd/Makefile.am
+++ b/mfd/Makefile.am
@@ -25,6 +25,7 @@ M4_FILES=\
  bi_curhdr.m4\
  bi_db.m4\
  bi_dns.m4\
+ bi_gethostname.m4\
  bi_getopt.m4\
  bi_gettext.m4\
  bi_header.m4\
diff --git a/mfd/bi_gethostname.m4 b/mfd/bi_gethostname.m4
new file mode 100644
index 00000000..315a2d1b
--- /dev/null
+++ b/mfd/bi_gethostname.m4
@@ -0,0 +1,123 @@
+/* This file is part of Mailfromd.             -*- c -*-
+   Copyright (C) 2009 Sergey Poznyakoff
+
+   This program 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 3, or (at your option)
+   any later version.
+
+   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#ifndef ENAMETOOLONG
+# define ENAMETOOLONG 0
+#endif
+
+#ifndef INITIAL_HOSTNAME_LENGTH
+# define INITIAL_HOSTNAME_LENGTH 34
+#endif
+
+#ifndef INITIAL_DOMAINNAME_LENGTH
+# define INITIAL_DOMAINNAME_LENGTH 34
+#endif
+
+/* string gethostname()
+
+   This implementation is based on xgethostname by Jim Meyering
+*/
+MF_DEFUN(gethostname, STRING)
+{
+        size_t size = INITIAL_HOSTNAME_LENGTH;
+        
+        MF_OBSTACK_BEGIN();
+        while (1) {
+                size_t nsize;
+                size_t size_1;
+                char *hostname;
+
+                MF_OBSTACK_GROW(NULL, size);
+                hostname = MF_OBSTACK_BASE();
+
+                /* Use SIZE_1 here rather than SIZE to work around the bug in
+                   SunOS 5.5's gethostname whereby it NUL-terminates HOSTNAME
+                   even when the name is as long as the supplied buffer.  */
+                size_1 = size - 1;
+                hostname[size_1 - 1] = '\0';
+                errno = 0;
+
+                if (gethostname(hostname, size_1) == 0) {
+                        if (!hostname[size_1 - 1])
+                                break;
+                } else if (errno != 0
+                           && errno != ENAMETOOLONG && errno != EINVAL
+                           /* OSX/Darwin does this when the buffer is not
+                              large enough */
+                           && errno != ENOMEM) {
+                        int saved_errno = errno;
+                        MF_OBSTACK_CANCEL();
+                        MF_THROW(mfe_failure,
+                                 "%s", mu_strerror(saved_errno));
+                }
+
+                nsize = size * 2;
+                if (nsize <= size) {
+                        MF_OBSTACK_CANCEL();
+                        MF_THROW(mfe_failure,
+                                 "%s", mu_strerror(ENOMEM));
+                }
+                size = nsize;
+        }
+        MF_RETURN_OBSTACK();
+}
+END
+
+/* string getdomainname()
+
+   This implementation is based on xgetdomainname by Jim Meyering
+*/
+MF_DEFUN(getdomainname, STRING)
+{
+        size_t size = INITIAL_DOMAINNAME_LENGTH;
+        
+        MF_OBSTACK_BEGIN();
+        while (1) {
+                size_t nsize;
+                size_t size_1;
+                char *domainname;
+                int rc;
+                
+                MF_OBSTACK_GROW(NULL, size);
+                domainname = MF_OBSTACK_BASE();
+
+                size_1 = size - 1;