Suspend exclusive database lock when scriptlets get called, allowing

read access in scriptlets. Only needed for DB_PRIVATE (aka global)

locking.

--- ./lib/backend/db3.c.orig	2017-12-01 14:27:03.193486711 +0000

+++ ./lib/backend/db3.c	2017-12-01 14:27:23.747426200 +0000

@@ -552,6 +552,46 @@ static void db3_dbSetFSync(rpmdb rdb, in

 static int db3_Ctrl(rpmdb rdb, dbCtrlOp ctrl)

 {

+    struct flock l;

+    int tries;

+    int fdno = -1;

+    dbiIndex dbi;

+    DB * db;

+

+    switch (ctrl) {

+    case DB_CTRL_SUSPEND_DBLOCK:

+    case DB_CTRL_RESUME_DBLOCK:

+	dbi = rdb->db_pkgs;	/* packages db only */

+	if (!dbi)

+	    return 1;

+	if (!dbi->cfg.dbi_lockdbfd || (dbi->dbi_flags & DBI_VERIFYONLY) != 0)

+	    return 0;

+	if (!(dbi->dbi_rpmdb->db_mode & (O_RDWR|O_WRONLY)))

+	    return 0;

+	if (_lockdbfd == 0)

+	    return 0;

+        db = dbi->dbi_db;

+	if (!(db->fd(db, &fdno) == 0 && fdno >= 0))

+	    return 1;

+	for (tries = 0; tries < 2; tries++) {

+	    memset(&l, 0, sizeof(l));

+	    l.l_whence = 0;

+	    l.l_start = 0;

+	    l.l_len = 0;

+	    l.l_type = ctrl == DB_CTRL_SUSPEND_DBLOCK ? F_RDLCK : F_WRLCK;

+	    if (!fcntl(fdno, tries ? F_SETLKW : F_SETLK, (void *)&l))

+		return 0;

+	    if (ctrl == DB_CTRL_SUSPEND_DBLOCK) {

+		rpmlog(RPMLOG_WARNING, _("could not suspend database lock\n"));

+		return 1;

+	    }

+	    if (tries == 0)

+		rpmlog(RPMLOG_WARNING, _("waiting to reestablish exclusive database lock\n"));

+	}

+	return 1;

+    default:

+        break;

+    }

     return 0;

 }

--- ./lib/backend/dbi.h.orig	2017-12-01 14:27:03.193486711 +0000

+++ ./lib/backend/dbi.h	2017-12-01 14:27:23.747426200 +0000

@@ -17,7 +17,9 @@ typedef enum dbCtrlOp_e {

     DB_CTRL_UNLOCK_RO		= 2,

     DB_CTRL_LOCK_RW		= 3,

     DB_CTRL_UNLOCK_RW		= 4,

-    DB_CTRL_INDEXSYNC		= 5

+    DB_CTRL_INDEXSYNC		= 5,

+    DB_CTRL_SUSPEND_DBLOCK      = 100,

+    DB_CTRL_RESUME_DBLOCK       = 101

 } dbCtrlOp;

 typedef struct dbiIndex_s * dbiIndex;

--- ./lib/rpmdb.c.orig	2017-12-01 14:27:03.190486720 +0000

+++ ./lib/rpmdb.c	2017-12-01 14:27:23.748426197 +0000

@@ -2639,6 +2639,12 @@ int rpmdbCtrl(rpmdb db, rpmdbCtrlOp ctrl

     case RPMDB_CTRL_INDEXSYNC:

 	dbctrl = DB_CTRL_INDEXSYNC;

 	break;

+    case RPMDB_CTRL_SUSPEND_DBLOCK:

+	dbctrl = DB_CTRL_SUSPEND_DBLOCK;

+	break;

+    case RPMDB_CTRL_RESUME_DBLOCK:

+	dbctrl = DB_CTRL_RESUME_DBLOCK;

+	break;

     }

     return dbctrl ? dbCtrl(db, dbctrl) : 1;

 }

--- ./lib/rpmdb.h.orig	2017-10-05 10:04:57.035602138 +0000

+++ ./lib/rpmdb.h	2017-12-01 14:27:23.748426197 +0000

@@ -35,7 +35,9 @@ typedef enum rpmdbCtrlOp_e {

     RPMDB_CTRL_UNLOCK_RO       = 2,

     RPMDB_CTRL_LOCK_RW         = 3,

     RPMDB_CTRL_UNLOCK_RW       = 4,

-    RPMDB_CTRL_INDEXSYNC       = 5

+    RPMDB_CTRL_INDEXSYNC       = 5,

+    RPMDB_CTRL_SUSPEND_DBLOCK  = 100,

+    RPMDB_CTRL_RESUME_DBLOCK   = 101

 } rpmdbCtrlOp;

 /** \ingroup rpmdb

--- ./lib/transaction.c.orig	2017-12-01 14:27:23.750426192 +0000

+++ ./lib/transaction.c	2017-12-01 14:28:43.232192224 +0000

@@ -1457,6 +1457,7 @@ rpmRC runScript(rpmts ts, rpmte te, Head

 		     stag != RPMTAG_PREUN &&

 		     stag != RPMTAG_PRETRANS &&

 		     stag != RPMTAG_VERIFYSCRIPT);

+    rpmdb rdb = rpmtsGetRdb(ts);

     /* Fake up a transaction element for triggers from rpmdb */

     if (te == NULL) {

@@ -1468,10 +1469,12 @@ rpmRC runScript(rpmts ts, rpmte te, Head

     if (sfd == NULL)

 	sfd = rpmtsScriptFd(ts);

+    rpmdbCtrl(rdb, RPMDB_CTRL_SUSPEND_DBLOCK);

     rpmswEnter(rpmtsOp(ts, RPMTS_OP_SCRIPTLETS), 0);

     rc = rpmScriptRun(script, arg1, arg2, sfd,

 		      prefixes, warn_only, rpmtsPlugins(ts));

     rpmswExit(rpmtsOp(ts, RPMTS_OP_SCRIPTLETS), 0);

+    rpmdbCtrl(rdb, RPMDB_CTRL_RESUME_DBLOCK);

     /* Map warn-only errors to "notfound" for script stop callback */

     stoprc = (rc != RPMRC_OK && warn_only) ? RPMRC_NOTFOUND : rc;