1 files changed, 301 insertions, 0 deletions

diff --git a/libetpan/src/data-types/maillock.c b/libetpan/src/data-types/maillock.c
new file mode 100644
index 0000000..b1741d0
--- a/dev/null
+++ b/libetpan/src/data-types/maillock.c
@@ -0,0 +1,301 @@
+/*
+ * libEtPan! -- a mail stuff library
+ *
+ * Copyright (C) 2001, 2005 - DINH Viet Hoa
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the libEtPan! project nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * $Id$
+ */
+
+#include "maillock.h"
+
+#include "libetpan-config.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <time.h>
+#include <string.h>
+#include "config.h"
+
+#ifdef HAVE_LIBLOCKFILE
+#include <lockfile.h>
+#endif
+
+/* ********************************************************************** */
+
+/* lock primitives */
+
+/* the lock code is modified from the dot lock file code from mail.local.c */
+
+/*
+                             SENDMAIL LICENSE
+
+The following license terms and conditions apply, unless a different
+license is obtained from Sendmail, Inc., 6425 Christie Ave, Fourth Floor,
+Emeryville, CA 94608, or by electronic mail at license@sendmail.com.
+
+License Terms:
+
+Use, Modification and Redistribution (including distribution of any
+modified or derived work) in source and binary forms is permitted only if
+each of the following conditions is met:
+
+1. Redistributions qualify as "freeware" or "Open Source Software" under
+   one of the following terms:
+
+   (a) Redistributions are made at no charge beyond the reasonable cost of
+       materials and delivery.
+
+   (b) Redistributions are accompanied by a copy of the Source Code or by an
+       irrevocable offer to provide a copy of the Source Code for up to three
+       years at the cost of materials and delivery.  Such redistributions
+       must allow further use, modification, and redistribution of the Source
+       Code under substantially the same terms as this license.  For the
+       purposes of redistribution "Source Code" means the complete compilable
+       and linkable source code of sendmail including all modifications.
+
+2. Redistributions of source code must retain the copyright notices as they
+   appear in each source code file, these license terms, and the
+   disclaimer/limitation of liability set forth as paragraph 6 below.
+
+3. Redistributions in binary form must reproduce the Copyright Notice,
+   these license terms, and the disclaimer/limitation of liability set
+   forth as paragraph 6 below, in the documentation and/or other materials
+   provided with the distribution.  For the purposes of binary distribution
+   the "Copyright Notice" refers to the following language:
+   "Copyright (c) 1998-2002 Sendmail, Inc.  All rights reserved."
+
+4. Neither the name of Sendmail, Inc. nor the University of California nor
+   the names of their contributors may be used to endorse or promote
+   products derived from this software without specific prior written
+   permission.  The name "sendmail" is a trademark of Sendmail, Inc.
+
+5. All redistributions must comply with the conditions imposed by the
+   University of California on certain embedded code, whose copyright
+   notice and conditions for redistribution are as follows:
+
+   (a) Copyright (c) 1988, 1993 The Regents of the University of
+       California.  All rights reserved.
+
+   (b) Redistribution and use in source and binary forms, with or without
+       modification, are permitted provided that the following conditions
+       are met:
+
+      (i)   Redistributions of source code must retain the above copyright
+            notice, this list of conditions and the following disclaimer.
+
+      (ii)  Redistributions in binary form must reproduce the above
+            copyright notice, this list of conditions and the following
+            disclaimer in the documentation and/or other materials provided
+            with the distribution.
+
+      (iii) Neither the name of the University nor the names of its
+            contributors may be used to endorse or promote products derived
+            from this software without specific prior written permission.
+
+6. Disclaimer/Limitation of Liability: THIS SOFTWARE IS PROVIDED BY
+   SENDMAIL, INC. AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
+   NO EVENT SHALL SENDMAIL, INC., THE REGENTS OF THE UNIVERSITY OF
+   CALIFORNIA OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+   INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+   USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+   ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+   THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
+*/
+
+/*
+  TODO : lock, prefer fcntl() over flock()
+         AND use dotlock code above
+*/
+
+        #define LOCKTO_RM       300/* timeout for stale lockfile removal */
+        #define LOCKTO_GLOB     400/* global timeout for lockfile creation */
+
+static int lock_common(const char * filename, int fd, short locktype)
+{
+  char lockfilename[PATH_MAX];
+  struct flock lock;
+  /* dot lock file */
+  int statfailed = 0;
+  time_t start;
+  int r;
+  int res;
+
+  /* dot lock file */
+
+  if (strlen(filename) + 6 > PATH_MAX) {
+    res = -1;
+    goto err;
+  }
+
+  snprintf(lockfilename, PATH_MAX, "%s.lock", filename);
+  
+#ifdef HAVE_LIBLOCKFILE
+  return lockfile_create(lockfilename, LOCKTO_GLOB, 0);
+#else
+
+  lock.l_start = 0;
+  lock.l_len = 0;
+  lock.l_pid = getpid();
+  lock.l_type = locktype;
+  lock.l_whence = SEEK_SET;
+
+  r = fcntl(fd, F_SETLKW, &lock);
+  if (r < 0) {
+    /* WARNING POSIX lock could not be applied */
+  }
+  
+  time(&start);
+  while (1) {
+    int fd;
+    struct stat st;
+    time_t now;
+    
+    /* global timeout */
+    time(&now);
+    if (now > start + LOCKTO_GLOB) {
+      res = -1;
+      goto unlock;
+    }
+
+    fd = open(lockfilename, O_WRONLY|O_EXCL|O_CREAT, 0);
+    if (fd >= 0) {
+      /* defeat lock checking programs which test pid */
+      write(fd, "0", 2);
+      close(fd);
+      break;
+    }
+    
+    /* libEtPan! - adds a delay of 5 seconds between each tries */
+    sleep(5);
+    
+    if (stat(lockfilename, &st) < 0) {
+      if (statfailed++ > 5) {
+        res = -1;
+        goto unlock;
+      }
+      continue;
+    }
+    statfailed = 0;
+    time(&now);
+
+    if (now < st.st_ctime + LOCKTO_RM)
+      continue;
+    
+    /* try to remove stale lockfile */
+    if (unlink(lockfilename) < 0) {
+      res = -1;
+      goto unlock;
+    }
+
+    /*
+      libEtPan! - removes this delay of 5 seconds,
+       maybe it was misplaced ?
+    */
+#if 0
+    sleep(5);
+#endif
+  }
+
+  return 0;
+
+ unlock:
+  lock.l_start = 0;
+  lock.l_len = 0;
+  lock.l_pid = getpid();
+  lock.l_type = F_UNLCK;
+  lock.l_whence = SEEK_SET;
+
+  r = fcntl(fd, F_SETLK, &lock);
+  if (r < 0) {
+    /* WARNING POSIX lock could not be applied */
+  }
+#endif
+ err:
+  return res;
+}
+
+static int unlock_common(const char * filename, int fd)
+{
+  char lockfilename[PATH_MAX];
+  struct flock lock;
+  int r;
+
+  if (strlen(filename) + 6 > PATH_MAX)
+    return -1;
+
+  snprintf(lockfilename, PATH_MAX, "%s.lock", filename);
+
+#ifdef HAVE_LIBLOCKFILE
+  return lockfile_remove(lockfilename);
+#else
+  
+  unlink(lockfilename);
+
+  lock.l_start = 0;
+  lock.l_len = 0;
+  lock.l_pid = getpid();
+  lock.l_type = F_UNLCK;
+  lock.l_whence = SEEK_SET;
+
+  r = fcntl(fd, F_SETLK, &lock);
+  if (r < 0) {
+    /* WARNING POSIX lock could not be applied */
+  }
+  
+  return 0;
+#endif
+}
+
+int maillock_read_lock(const char * filename, int fd)
+{
+  return lock_common(filename, fd, F_RDLCK);
+}
+
+int maillock_read_unlock(const char * filename, int fd)
+{
+  return unlock_common(filename, fd);
+}
+
+int maillock_write_lock(const char * filename, int fd)
+{
+  return lock_common(filename, fd, F_WRLCK);
+}
+
+int maillock_write_unlock(const char * filename, int fd)
+{
+  return unlock_common(filename, fd);
+}