Initial checkin

Imported from subversion report, converted to git. Updated all paths in
scripts and makefiles, reflecting the new directory hierarchy.

1 files changed, 100 insertions, 0 deletions

diff --git a/maildir/maildircache.h b/maildir/maildircache.h
new file mode 100644
index 0000000..a33a857
--- /dev/null
+++ b/maildir/maildircache.h
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+/*
+** Copyright 1998 - 2001 Double Precision, Inc.  See COPYING for
+** distribution information.
+*/
+
+
+
+/*
+
+The login cache is used to try to eliminate a call to getpw for each and
+every http request, which can be quite expensive on systems with large number
+of users and heave web traffic.  The following information is saved in the
+cache:
+
+userid
+groupid
+directory (presumably of a maildir)
+certain environment variables
+
+
+The interface is abstracted into these functions:
+
+maildir_cache_init(seconds, cachedir, cacheowner, authvars)
+
+maildir_cache_start()
+maildir_cache_save(userid, login_time, homedir, uid, gid)
+maildir_cache_cancel()
+
+maildir_cache_search(userid, login_time, callback_func, callback_func_arg)
+
+The prepare, save, and cancel functions are used to cache the login
+information.
+maildir_cache_start should be called before we attempt to log in, when we're
+running as root.  We're about to drop root privileges after a successful
+login, but we need to be root in order to update the cache directory, so
+maildir_cache_start forks a child process, which will wait patiently in
+the background.
+
+maildir_cache_save will sends the cacheable information to the child process,
+over a secured pipe.  maildir_cache_save will be called after a successful
+login.
+
+maildir_cache_cancel shall be called if the login failed.  It will kill the
+child process.
+
+The search function is called to query the cache file.  If it succeeds, it
+calls the callback function with the userid, groupid, and homedir.
+
+There is no need to manually remove an expired cache entry upon logout.
+It will be cleaned up by a separate cron job.
+
+
+init_login_cache should be called before any other function.  It's argument
+specifies: that hard timeout interval - the fixed amount of time after which
+any login becomes invalid; the login cache directory; userid that owns the
+login cache directory; the environment variables to save in the login cache
+directory.
+
+The login cache functions receive the saved original login time.  The login
+cache information is saved in a directory that should be writable by cache
+owner only.  The cache directory contains subdirectories whose name is derived
+by dividing the login time by the hard timeout interval.  For example, when
+logging on in the afternoon of November 27, 1999, the current time, in seconds,
+is 943725152.  With the login interval being the default of 2 hours, 7200
+seconds, the top level directory would be 943725152 / 7200 or 131072.
+
+What this allows us to do is to quickly remove expired login entries, simply
+by reading the top level cache directory, and recursively deleting subdirs
+whose names are too old to contain any logins that are still active.
+
+If the login name is 'john', the cached login will be saved in the file
+131072/jo/john, creating the subdirectories if necessary.
+
+Because the login name can contain special characters, the special characters
+will be escaped.  See the code for more info.
+
+*/
+
+#ifndef	logincache_h
+#define	logincache_h
+
+#include	<sys/types.h>
+#include	<time.h>
+#include	<pwd.h>
+
+
+extern int maildir_cache_init(time_t, const char *, const char *,
+			      const char * const *);
+extern void maildir_cache_start(void);
+extern void maildir_cache_save(const char *, time_t, const char *, uid_t,
+			       gid_t);
+extern void maildir_cache_cancel(void);
+
+extern int maildir_cache_search(const char *, time_t,
+				int (*)(uid_t, gid_t, const char *, void *),
+				void *);
+
+extern void maildir_cache_purge();
+
+#endif