Suspend exclusive database lock when scriptlets get called

Suspend exclusive database lock when scriptlets get called, allowing
read access in scriptlets. Only needed for DB_PRIVATE (aka global)
locking.

6 files changed, 89 insertions, 0 deletions

diff --git a/lib/backend/db3.c b/lib/backend/db3.c
index a47d08b78..a55a608cf 100644
--- a/lib/backend/db3.c
+++ b/lib/backend/db3.c
@@ -632,3 +632,59 @@ int dbiOpen(rpmdb rdb, rpmDbiTagVal rpmtag, dbiIndex * dbip, int flags)
 
     return rc;
 }
+
+int dbiSuspendDBLock(dbiIndex dbi, unsigned int flags)
+{
+    struct flock l;
+    int rc = 0;
+    int fdno = -1;
+
+    if (!dbi->dbi_lockdbfd)
+	return 0;
+    if (!(dbi->dbi_rpmdb->db_mode & (O_RDWR|O_WRONLY)))
+	return 0;
+    if (_lockdbfd == 0)
+	return 0;
+    if (!(dbi->dbi_db->fd(dbi->dbi_db, &fdno) == 0 && fdno >= 0))
+	return 1;
+    memset(&l, 0, sizeof(l));
+    l.l_whence = 0;
+    l.l_start = 0;
+    l.l_len = 0;
+    l.l_type = F_RDLCK;
+    rc = fcntl(fdno, F_SETLK, (void *)&l);
+    if (rc)
+	rpmlog(RPMLOG_WARNING, _("could not suspend database lock\n"));
+    return rc;
+}
+
+int dbiResumeDBLock(dbiIndex dbi, unsigned int flags)
+{
+    struct flock l;
+    int rc = 0;
+    int tries;
+    int fdno = -1;
+
+    if (!dbi->dbi_lockdbfd)
+	return 0;
+    if (!(dbi->dbi_rpmdb->db_mode & (O_RDWR|O_WRONLY)))
+	return 0;
+    if (_lockdbfd == 0)
+	return 0;
+    if (!(dbi->dbi_db->fd(dbi->dbi_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 = F_WRLCK;
+	rc = fcntl(fdno, tries ? F_SETLKW : F_SETLK, (void *)&l);
+	if (!rc)
+	    break;
+	if (tries == 0)
+	    rpmlog(RPMLOG_WARNING, _("waiting to reestablish exclusive database lock\n"));
+    }
+    return rc;
+}
+
diff --git a/lib/backend/dbi.h b/lib/backend/dbi.h
index 49fa1f1f2..3d848a8a0 100644
--- a/lib/backend/dbi.h
+++ b/lib/backend/dbi.h
@@ -81,6 +81,24 @@ struct dbiIndex_s {
 extern "C" {
 #endif
 
+/** \ingroup dbi
+ * Suspend the exclusive lock on the dbi
+ * @param dbi		index database handle
+ * @param flags		(unused)
+ * @return		0 on success
+ */
+RPM_GNUC_INTERNAL
+int dbiSuspendDBLock(dbiIndex dbi, unsigned int flags);
+
+/** \ingroup dbi
+ * Reacquire an exclusive lock on the dbi
+ * @param dbi		index database handle
+ * @param flags		(unused)
+ * @return		0 on success
+ */
+RPM_GNUC_INTERNAL
+int dbiResumeDBLock(dbiIndex dbi, unsigned int flags);
+
 
 RPM_GNUC_INTERNAL
 /* Globally enable/disable fsync in the backend */
diff --git a/lib/psm.c b/lib/psm.c
index c786f1e37..aad047fcf 100644
--- a/lib/psm.c
+++ b/lib/psm.c
@@ -419,10 +419,12 @@ static rpmRC runScript(rpmpsm psm, ARGV_const_t prefixes,
     if (sfd == NULL)
 	sfd = rpmtsScriptFd(psm->ts);
 
+    rpmtsSuspendResumeDBLock(psm->ts, 0);
     rpmswEnter(rpmtsOp(psm->ts, RPMTS_OP_SCRIPTLETS), 0);
     rc = rpmScriptRun(script, arg1, arg2, sfd,
 		      prefixes, warn_only, selinux);
     rpmswExit(rpmtsOp(psm->ts, RPMTS_OP_SCRIPTLETS), 0);
+    rpmtsSuspendResumeDBLock(psm->ts, 1);
 
     /* Map warn-only errors to "notfound" for script stop callback */
     stoprc = (rc != RPMRC_OK && warn_only) ? RPMRC_NOTFOUND : rc;
diff --git a/lib/rpmdb.c b/lib/rpmdb.c
index 1a2fda504..c17dcbfc6 100644
--- a/lib/rpmdb.c
+++ b/lib/rpmdb.c
@@ -781,6 +781,12 @@ int rpmdbSync(rpmdb db)
     return dbiForeach(db->_dbi, dbiSync, 0);
 }
 
+int rpmdbSuspendResumeDBLock(rpmdb db, int mode)
+{
+    if (db == NULL) return 0;
+    return dbiForeach(db->_dbi, mode ? dbiResumeDBLock : dbiSuspendDBLock, 0);
+}
+
 static rpmdb newRpmdb(const char * root, const char * home,
 		      int mode, int perms, int flags)
 {
diff --git a/lib/rpmts.c b/lib/rpmts.c
index 964273473..d3b893a1d 100644
--- a/lib/rpmts.c
+++ b/lib/rpmts.c
@@ -95,6 +95,11 @@ int rpmtsOpenDB(rpmts ts, int dbmode)
     return rc;
 }
 
+int rpmtsSuspendResumeDBLock(rpmts ts, int mode)
+{
+    return rpmdbSuspendResumeDBLock(ts->rdb, mode);
+}
+
 int rpmtsInitDB(rpmts ts, int dbmode)
 {
     rpmlock lock = rpmtsAcquireLock(ts);
diff --git a/lib/rpmts.h b/lib/rpmts.h
index 0b8d970e7..059f46d24 100644
--- a/lib/rpmts.h
+++ b/lib/rpmts.h
@@ -423,6 +423,8 @@ rpmdb rpmtsGetRdb(rpmts ts);
 void * rpmtsNotify(rpmts ts, rpmte te,
                 rpmCallbackType what, rpm_loff_t amount, rpm_loff_t total);
 
+int rpmtsSuspendResumeDBLock(rpmts ts, int mode);
+
 /** \ingroup rpmts
  * Return number of (ordered) transaction set elements.
  * @param ts		transaction set