Revise the mailbox locking functions.

The locker is created by the following call:

    mu_locker_create_ext(&locker, filename, &hints);

The last arguments points to a structure mu_locker_hints_t, which
defines the settings for the locker.  NULL value implies default.
Settings of an existing locker can be modified using the following
call:

    mu_locker_modify(locker, &hints);

Current settings can be examined using mu_locker_get_hints.

The functions mu_locker_destroy, mu_locker_lock_mode, mu_locker_lock,
mu_locker_touchlock, mu_locker_unlock, and mu_locker_remove_lock remained
unchanged.  Rest of functions is deprecated, but retained for a couple
of releases for the sake of backward compatibility.

Constants (locker types, flags, etc) are also revisited.

This commit also fixes a bug in mu_spawnvp function, which was discovered
when testing external lockers.

* include/mailutils/locker.h: Major rewrite.
(MU_LOCKER_DEFAULT_EXPIRE_TIME)
(MU_LOCKER_DEFAULT_RETRY_COUNT)
(MU_LOCKER_DEFAULT_RETRY_SLEEP)
(MU_LOCKER_DEFAULT_EXT_LOCKER): New defines.
(mu_locker_hints_t): New data type.
(MU_LOCKER_FLAG_RETRY)
(MU_LOCKER_FLAG_EXPIRE_TIME)
(MU_LOCKER_FLAG_CHECK_PID)
(MU_LOCKER_FLAG_TYPE,MU_LOCKER_FLAGS_ALL): New defines.
(mu_locker_create_ext, mu_locker_modify)
(mu_locker_get_hints): New functions.
(mu_locker_create,mu_locker_set_default_flags)
(mu_locker_set_default_retry_timeout)
(mu_locker_set_default_retry_count)
(mu_locker_set_default_expire_timeout)
(mu_locker_set_default_external_program)
(mu_locker_set_flags,mu_locker_mod_flags)
(mu_locker_set_expire_time,mu_locker_set_retries)
(mu_locker_set_retry_sleep,mu_locker_set_external)
(mu_locker_get_flags,mu_locker_get_expire_time)
(mu_locker_get_retries,mu_locker_get_retry_sleep): Mark as deprecated.
* libmailutils/base/locker.c: Rewrite.
* libmailutils/cli/stdcapa.c: New locking statements: type and
retry-sleep.  retry-timeout is deprecated.

* libmailutils/tests/lck.c: Use new locker functions.
* libmailutils/tests/lock.at: Test the external locker.

* libmailutils/base/spawnvp.c (mu_spawnvp): Restore the default SIGCHLD
handler while waiting for the process to terminate.

* dotlock/dotlock.c: Use new locker functions.
* lib/manlock.c: Likewise.
* libmailutils/base/amd.c: Likewise.
* libmu_dbm/berkeley.c: Likewise.
* libmu_sieve/extensions/vacation.c: Likewise.
* libproto/dotmail/dotmail.c: Likewise.
* libproto/mbox/mboxrd.c: Likewise.
* mail/copy.c: Likewise.

* mda/lmtpd/lmtpd.c: Modify mu_locker_defaults instead of using
deprecated functions.
* mda/mda/mda.c: Likewise.
* mda/putmail/putmail.c: Likewise.

* NEWS: Document changes.
* configure.ac: Version 3.12.90.
* doc/texinfo/Makefile.am: Add programs/dotlock.texi
* doc/texinfo/programs.texi: Rewrite the locking section.
New section: dotlock.
* doc/texinfo/programs/dotlock.texi: New file.

1 files changed, 12 insertions, 8 deletions

diff --git a/lib/manlock.c b/lib/manlock.c
index 0c32115cc..e06387807 100644
--- a/lib/manlock.c
+++ b/lib/manlock.c
@@ -128,14 +128,17 @@ mailbox_open_and_lock (mu_mailbox_t mbox, int flags)
 
   if (lock)
     {
-      status = mu_locker_get_flags (lock, &flags);
+      mu_locker_hints_t hints;
+
+      hints.flags = MU_LOCKER_FLAG_TYPE;
+      status = mu_locker_get_hints (lock, &hints);
       if (status)
 	{
-	  mu_diag_funcall (MU_DIAG_ERROR, "mu_locker_get_flags", urlstr,
+	  mu_diag_funcall (MU_DIAG_ERROR, "mu_locker_get_hints", urlstr,
 			   status);
 	  return MU_ERR_FAILURE;
 	}
-      if (flags & MU_LOCKER_NULL)
+      if (hints.type == MU_LOCKER_TYPE_NULL)
 	lock = NULL;
     }
   
@@ -157,10 +160,10 @@ mailbox_open_and_lock (mu_mailbox_t mbox, int flags)
       if (!fname)
 	return MU_ERR_FAILURE;
 	  
-      status = mu_locker_create (&lock, fname, 0);
+      status = mu_locker_create_ext (&lock, fname, NULL);
       if (status)
 	{
-	  mu_diag_funcall (MU_DIAG_ERROR, "mu_locker_create", fname, status);
+	  mu_diag_funcall (MU_DIAG_ERROR, "mu_locker_create_ext", fname, status);
 	  free (fname);
 	  return MU_ERR_FAILURE;
 	}
@@ -245,13 +248,14 @@ manlock_lock (mu_mailbox_t mbox)
   mu_locker_t lock = NULL;
   const char *name;
   int status;
-
+  mu_locker_hints_t hints = { .flags = MU_LOCKER_FLAG_CHECK_PID };
+  
   if (!manlock_mandatory_locking)
     return 0;
   mu_mailbox_get_url (mbox, &url);
   name = mu_url_to_string (url);
-  mu_mailbox_get_locker (mbox, &lock);  
-  mu_locker_mod_flags (lock, MU_LOCKER_PID, mu_locker_set_bit);
+  mu_mailbox_get_locker (mbox, &lock);
+  mu_locker_modify (lock, &hints);
   if ((status = mu_locker_lock (lock)))
     {
       mu_diag_output (MU_DIAG_NOTICE, _("locking mailbox `%s' failed: %s"),