Initial Alpine Version

1 files changed, 175 insertions, 0 deletions

diff --git a/imap/src/mlock/mlock.c b/imap/src/mlock/mlock.c
new file mode 100644
index 00000000..1dca40ed
--- /dev/null
+++ b/imap/src/mlock/mlock.c
@@ -0,0 +1,175 @@
+/* ========================================================================
+ * Copyright 1988-2008 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:	Standalone Mailbox Lock program
+ *
+ * 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:	8 February 1999
+ * Last Edited:	3 March 2008
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sysexits.h>
+#include <syslog.h>
+#include <grp.h>
+#include <sys/types.h>
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <sys/param.h>
+#include <stdlib.h>
+#include <netdb.h>
+#include <ctype.h>
+#include <string.h>
+
+#define LOCKTIMEOUT 5		/* lock timeout in minutes */
+#define LOCKPROTECTION 0664
+
+#ifndef MAXHOSTNAMELEN		/* Solaris still sucks */
+#define MAXHOSTNAMELEN 256
+#endif
+
+/* Fatal error
+ * Accepts: Message string
+ *	    exit code
+ * Returns: code
+ */
+
+int die (char *msg,int code)
+{
+  syslog (LOG_NOTICE,"(%u) %s",code,msg);
+  write (1,"?",1);		/* indicate "impossible" failure */
+  return code;
+}
+
+
+int main (int argc,char *argv[])
+{
+  int ld,i;
+  int tries = LOCKTIMEOUT * 60 - 1;
+  char *s,*dir,*file,*lock,*hitch,tmp[1024];
+  size_t dlen,len;
+  struct stat sb,fsb;
+  struct group *grp = getgrnam ("mail");
+				/* get syslog */
+  openlog (argv[0],LOG_PID,LOG_MAIL);
+  if (!grp || (grp->gr_gid != getegid ()))
+    return die ("not setgid mail",EX_USAGE);
+  if (argc != 3) return die ("invalid arguments",EX_USAGE);
+  for (s = argv[1]; *s; s++)
+    if (!isdigit (*s)) return die ("invalid fd",EX_USAGE);
+				/* find directory */
+  if ((*argv[2] != '/') || !(file = strrchr (argv[2],'/')) || !file[1])
+    return die ("invalid path",EX_USAGE);
+				/* calculate lengths of directory and file */
+  if (!(dlen = file - argv[2])) dlen = 1;
+  len = strlen (++file);
+				/* make buffers */
+  dir = (char *) malloc (dlen + 1);
+  lock = (char *) malloc (len + 6);
+  hitch = (char *) malloc (len + 6 + 40 + MAXHOSTNAMELEN);
+  if (!dir || !lock || !hitch) return die ("malloc failure",errno);
+  strncpy (dir,argv[2],dlen);	/* connect to desired directory */
+  dir[dlen] = '\0';
+  printf ("dir=%s, file=%s\n",dir,file);
+  chdir (dir);
+				/* get device/inode of file descriptor */
+  if (fstat (atoi (argv[1]),&fsb)) return die ("fstat failure",errno);
+				/* better be a regular file */
+  if ((fsb.st_mode & S_IFMT) != S_IFREG)
+    return die ("fd not regular file",EX_USAGE);
+				/* now get device/inode of file */
+  if (lstat (file,&sb)) return die ("lstat failure",errno);
+				/* does it match? */
+  if ((sb.st_mode & S_IFMT) != S_IFREG)
+    return die ("name not regular file",EX_USAGE);
+  if ((sb.st_dev != fsb.st_dev) || (sb.st_ino != fsb.st_ino))
+    return die ("fd and name different",EX_USAGE);
+				/* build lock filename */
+  sprintf (lock,"%s.lock",file);
+  if (!lstat (lock,&sb) && ((sb.st_mode & S_IFMT) != S_IFREG))
+    return die ("existing lock not regular file",EX_NOPERM);
+
+  do {				/* until OK or out of tries */
+    if (!stat (lock,&sb) && (time (0) > (sb.st_ctime + LOCKTIMEOUT * 60)))
+      unlink (lock);		/* time out lock if enough time has passed */
+    /* SUN-OS had an NFS
+     * As kludgy as an albatross;
+     * And everywhere that it was installed,
+     * It was a total loss.
+     * -- MRC 9/25/91
+     */
+				/* build hitching post file name */
+    sprintf (hitch,"%s.%lu.%lu.",lock,(unsigned long) time (0),
+	     (unsigned long) getpid ());
+    len = strlen (hitch);	/* append local host name */
+    gethostname (hitch + len,MAXHOSTNAMELEN);
+				/* try to get hitching-post file */
+    if ((ld = open (hitch,O_WRONLY|O_CREAT|O_EXCL,LOCKPROTECTION)) >= 0) {
+				/* make sure others can break the lock */
+      chmod (hitch,LOCKPROTECTION);
+				/* get device/inode of hitch file */
+      if (fstat (ld,&fsb)) return die ("hitch fstat failure",errno);
+      close (ld);		/* close the hitching-post */
+      /* Note: link() may return an error even if it actually succeeded.  So we
+       * always check for success via the link count, and ignore the error if
+       * the link count is right.
+       */
+				/* tie hitching-post to lock */
+      i = link (hitch,lock) ? errno : 0;
+				/* success if link count now 2 */
+      if (stat (hitch,&sb) || (sb.st_nlink != 2) ||
+	  (fsb.st_dev != sb.st_dev) || (fsb.st_ino != sb.st_ino)) {
+	ld = -1;		/* failed to hitch */
+	if (i == EPERM) {	/* was it because links not allowed? */
+	  /* Probably a FAT filesystem on Linux.  It can't be NFS, so try
+	   * creating the lock file directly.
+	   */
+	  if ((ld = open (lock,O_WRONLY|O_CREAT|O_EXCL,LOCKPROTECTION)) >= 0) {
+	    /* get device/inode of lock file */
+	    if (fstat (ld,&fsb)) return die ("lock fstat failure",errno);
+	    close (ld);		/* close the file */
+	  }
+				/* give up immediately if protection failure */
+	  else if (errno != EEXIST) tries = 0;
+	}
+      }
+      unlink (hitch);		/* flush hitching post */
+    }
+				/* give up immediately if protection failure */
+    else if (errno == EACCES) tries = 0;
+    if (ld < 0) {		/* lock failed */
+      if (tries--) sleep (1);	/* sleep 1 second and try again */
+      else {
+	write (1,"-",1);	/* hard failure */
+	return EX_CANTCREAT;
+      }
+    }
+  } while (ld < 0);
+  write (1,"+",1);		/* indicate that all is well */
+  read (0,tmp,1);		/* read continue signal from parent */
+				/* flush the lock file */
+  if (!stat (lock,&sb) && (fsb.st_dev == sb.st_dev) &&
+      (fsb.st_ino == sb.st_ino)) unlink (lock);
+  else syslog (LOG_NOTICE,"lock file %s/%s changed dev/inode",dir,lock);
+  return EX_OK;
+}