Initial Alpine Version

1 files changed, 76 insertions, 0 deletions

diff --git a/imap/src/osdep/unix/flocklnx.c b/imap/src/osdep/unix/flocklnx.c
new file mode 100644
index 00000000..ca0112ac
--- /dev/null
+++ b/imap/src/osdep/unix/flocklnx.c
@@ -0,0 +1,76 @@
+/* ========================================================================
+ * Copyright 1988-2006 University of Washington
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 
+ * ========================================================================
+ */
+
+/*
+ * Program:	Safe File Lock for Linux
+ *
+ * Author:	Mark Crispin
+ *		Networks and Distributed Computing
+ *		Computing & Communications
+ *		University of Washington
+ *		Administration Building, AG-44
+ *		Seattle, WA  98195
+ *		Internet: MRC@CAC.Washington.EDU
+ *
+ * Date:	20 April 2005
+ * Last Edited:	30 August 2006
+ */
+ 
+#undef flock
+
+#include <sys/vfs.h>
+#ifndef NFS_SUPER_MAGIC
+#define NFS_SUPER_MAGIC 0x6969
+#endif
+
+int safe_flock (int fd,int op)
+{
+  struct statfs sfbuf;
+  char tmp[MAILTMPLEN];
+  int e;
+  int logged = 0;
+  /* Check for NFS because Linux 2.6 broke flock() on NFS.  Instead of being
+   * a no-op, flock() on NFS now returns ENOLCK.  Read
+   *   https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=123415
+   * for the gruesome details.
+   */
+				/* check filesystem type */
+  while ((e = fstatfs (fd,&sfbuf)) && (errno == EINTR));
+  if (!e) switch (sfbuf.f_type) {
+  case NFS_SUPER_MAGIC:		/* always a fast no-op on NFS */
+    break;
+  default:			/* allow on other filesystem types */
+				/* do the lock */
+    while (flock (fd,op)) switch (errno) {
+    case EINTR:			/* interrupt */
+      break;
+    case ENOLCK:		/* lock table is full */
+      sprintf (tmp,"File locking failure: %s",strerror (errno));
+      mm_log (tmp,WARN);	/* give the user a warning of what happened */
+      if (!logged++) syslog (LOG_ERR,tmp);
+				/* return failure if non-blocking lock */
+      if (op & LOCK_NB) return -1;
+      sleep (5);		/* slow down in case it loops */
+      break;
+    case EWOULDBLOCK:		/* file is locked, LOCK_NB should be set */
+      if (op & LOCK_NB) return -1;
+    case EBADF:			/* not valid open file descriptor */
+    case EINVAL:		/* invalid operator */
+    default:			/* other error code? */
+      sprintf (tmp,"Unexpected file locking failure: %s",strerror (errno));
+      fatal (tmp);
+    }
+    break;
+  }
+  return 0;			/* success */
+}