1 files changed, 82 insertions, 0 deletions
diff --git a/lib/lock.c b/lib/lock.c
new file mode 100644
index 000000000..e0af62a78
--- /dev/null
+++ b/lib/lock.c
@@ -0,0 +1,82 @@
+/*
+ * libdpkg - Debian packaging suite library routines
+ * lock.c - packages database locking
+ *
+ * Copyright (C) 1994,1995 Ian Jackson <iwj10@cus.cam.ac.uk>
+ *
+ * This 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 2,
+ * or (at your option) any later version.
+ *
+ * This 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 dpkg; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <assert.h>
+#include <fcntl.h>
+#include <sys/file.h>
+
+#include "config.h"
+#include "dpkg.h"
+#include "dpkg-db.h"
+
+static char *dblockfile= 0;
+static int dblockfd= -1;
+
+static void cu_unlockdb(int argc, void **argv) {
+  struct flock fl;
+  assert(dblockfile);
+  assert(dblockfd >= 0);
+  fl.l_type= F_UNLCK;
+  fl.l_whence= SEEK_SET;
+  fl.l_start= 0;
+  fl.l_len= 1;
+  if (fcntl(dblockfd,F_SETLK,&fl) == -1)
+    ohshite("unable to unlock dpkg status database");
+}
+
+void unlockdatabase(const char *admindir) {
+  pop_cleanup(ehflag_normaltidy); /* calls cu_unlockdb */
+}
+
+void lockdatabase(const char *admindir) {
+  int n;
+  struct flock fl;
+  
+  if (!dblockfile) {
+    n= strlen(admindir);
+    dblockfile= m_malloc(n+sizeof(LOCKFILE)+2);
+    strcpy(dblockfile,admindir);
+    strcpy(dblockfile+n, "/" LOCKFILE);
+  }
+  if (dblockfd == -1) {
+    dblockfd= open(dblockfile, O_RDWR|O_CREAT|O_TRUNC, 0660);
+    if (dblockfd == -1) {
+      if (errno == EPERM)
+        ohshit("you do not have permission to lock the dpkg status database");
+      ohshite("unable to open/create status database lockfile");
+    }
+  }
+  fl.l_type= F_WRLCK;
+  fl.l_whence= SEEK_SET;
+  fl.l_start= 0;
+  fl.l_len= 1;
+  if (fcntl(dblockfd,F_SETLK,&fl) == -1) {
+    if (errno == EWOULDBLOCK || errno == EAGAIN)
+      ohshit("status database area is locked - another dpkg/dselect is running");
+    ohshite("unable to lock dpkg status database");
+  }
+  push_cleanup(cu_unlockdb,~0, 0,0, 0);
+}