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[Emacs-diffs] Changes to emacs/src/filelock.c


From: Miles Bader
Subject: [Emacs-diffs] Changes to emacs/src/filelock.c
Date: Fri, 04 Apr 2003 01:23:50 -0500

Index: emacs/src/filelock.c
diff -c emacs/src/filelock.c:1.97 emacs/src/filelock.c:1.98
*** emacs/src/filelock.c:1.97   Sun Jul 14 20:00:36 2002
--- emacs/src/filelock.c        Tue Feb  4 09:03:12 2003
***************
*** 80,93 ****
  #ifndef WTMP_FILE
  #define WTMP_FILE "/var/log/wtmp"
  #endif
!   
  /* The strategy: to lock a file FN, create a symlink .#FN in FN's
     directory, with link data address@hidden'.  This avoids a single
     mount (== failure) point for lock files.
  
     When the host in the lock data is the current host, we can check if
     the pid is valid with kill.
!    
     Otherwise, we could look at a separate file that maps hostnames to
     reboot times to see if the remote pid can possibly be valid, since we
     don't want Emacs to have to communicate via pipes or sockets or
--- 80,93 ----
  #ifndef WTMP_FILE
  #define WTMP_FILE "/var/log/wtmp"
  #endif
! 
  /* The strategy: to lock a file FN, create a symlink .#FN in FN's
     directory, with link data address@hidden'.  This avoids a single
     mount (== failure) point for lock files.
  
     When the host in the lock data is the current host, we can check if
     the pid is valid with kill.
! 
     Otherwise, we could look at a separate file that maps hostnames to
     reboot times to see if the remote pid can possibly be valid, since we
     don't want Emacs to have to communicate via pipes or sockets or
***************
*** 105,119 ****
     files to be useful on old systems lacking symlinks, nowadays
     virtually all such systems are probably single-user anyway, so it
     didn't seem worth the complication.
!    
     Similarly, we don't worry about a possible 14-character limit on
     file names, because those are all the same systems that don't have
     symlinks.
!    
     This is compatible with the locking scheme used by Interleaf (which
     has contributed this implementation for Emacs), and was designed by
     Ethan Jacobson, Kimbo Mundy, and others.
!    
     address@hidden/address@hidden  */
  
  
--- 105,119 ----
     files to be useful on old systems lacking symlinks, nowadays
     virtually all such systems are probably single-user anyway, so it
     didn't seem worth the complication.
! 
     Similarly, we don't worry about a possible 14-character limit on
     file names, because those are all the same systems that don't have
     symlinks.
! 
     This is compatible with the locking scheme used by Interleaf (which
     has contributed this implementation for Emacs), and was designed by
     Ethan Jacobson, Kimbo Mundy, and others.
! 
     address@hidden/address@hidden  */
  
  
***************
*** 344,350 ****
       do something to support 14-character-max file names.  */
    for (p = lockfile + strlen (lockfile); p != lockfile && *p != '/'; p--)
      p[2] = *p;
!   
    /* Insert the `.#'.  */
    p[1] = '.';
    p[2] = '#';
--- 344,350 ----
       do something to support 14-character-max file names.  */
    for (p = lockfile + strlen (lockfile); p != lockfile && *p != '/'; p--)
      p[2] = *p;
! 
    /* Insert the `.#'.  */
    p[1] = '.';
    p[2] = '#';
***************
*** 368,374 ****
  
  static int
  lock_file_1 (lfname, force)
!      char *lfname; 
       int force;
  {
    register int err;
--- 368,374 ----
  
  static int
  lock_file_1 (lfname, force)
!      char *lfname;
       int force;
  {
    register int err;
***************
*** 394,400 ****
             (unsigned long) getpid (), (unsigned long) boot_time);
    else
      sprintf (lock_info_str, "address@hidden", user_name, host_name,
!            (unsigned long) getpid ());    
  
    err = symlink (lock_info_str, lfname);
    if (errno == EEXIST && force)
--- 394,400 ----
             (unsigned long) getpid (), (unsigned long) boot_time);
    else
      sprintf (lock_info_str, "address@hidden", user_name, host_name,
!            (unsigned long) getpid ());
  
    err = symlink (lock_info_str, lfname);
    if (errno == EEXIST && force)
***************
*** 448,454 ****
  #endif
      }
    while (len >= bufsize);
!   
    /* If nonexistent lock file, all is well; otherwise, got strange error. */
    if (len == -1)
      {
--- 448,454 ----
  #endif
      }
    while (len >= bufsize);
! 
    /* If nonexistent lock file, all is well; otherwise, got strange error. */
    if (len == -1)
      {
***************
*** 458,464 ****
  
    /* Link info exists, so `len' is its length.  Null terminate.  */
    lfinfo[len] = 0;
!   
    /* Even if the caller doesn't want the owner info, we still have to
       read it to determine return value, so allocate it.  */
    if (!owner)
--- 458,464 ----
  
    /* Link info exists, so `len' is its length.  Null terminate.  */
    lfinfo[len] = 0;
! 
    /* Even if the caller doesn't want the owner info, we still have to
       read it to determine return value, so allocate it.  */
    if (!owner)
***************
*** 466,472 ****
        owner = (lock_info_type *) alloca (sizeof (lock_info_type));
        local_owner = 1;
      }
!   
    /* Parse address@hidden:BOOT_TIME.  If can't parse, return -1.  */
    /* The USER is everything before the first @.  */
    at = index (lfinfo, '@');
--- 466,472 ----
        owner = (lock_info_type *) alloca (sizeof (lock_info_type));
        local_owner = 1;
      }
! 
    /* Parse address@hidden:BOOT_TIME.  If can't parse, return -1.  */
    /* The USER is everything before the first @.  */
    at = index (lfinfo, '@');
***************
*** 480,486 ****
    owner->user = (char *) xmalloc (len + 1);
    strncpy (owner->user, lfinfo, len);
    owner->user[len] = 0;
!   
    /* The PID is everything from the last `.' to the `:'.  */
    owner->pid = atoi (dot + 1);
    colon = dot;
--- 480,486 ----
    owner->user = (char *) xmalloc (len + 1);
    strncpy (owner->user, lfinfo, len);
    owner->user[len] = 0;
! 
    /* The PID is everything from the last `.' to the `:'.  */
    owner->pid = atoi (dot + 1);
    colon = dot;
***************
*** 500,506 ****
  
    /* We're done looking at the link info.  */
    xfree (lfinfo);
!   
    /* On current host?  */
    if (STRINGP (Fsystem_name ())
        && strcmp (owner->host, SDATA (Fsystem_name ())) == 0)
--- 500,506 ----
  
    /* We're done looking at the link info.  */
    xfree (lfinfo);
! 
    /* On current host?  */
    if (STRINGP (Fsystem_name ())
        && strcmp (owner->host, SDATA (Fsystem_name ())) == 0)
***************
*** 524,530 ****
           here's where we'd do it.  */
        ret = 1;
      }
!   
    /* Avoid garbage.  */
    if (local_owner || ret <= 0)
      {
--- 524,530 ----
           here's where we'd do it.  */
        ret = 1;
      }
! 
    /* Avoid garbage.  */
    if (local_owner || ret <= 0)
      {
***************
*** 543,549 ****
  static int
  lock_if_free (clasher, lfname)
       lock_info_type *clasher;
!      register char *lfname; 
  {
    while (lock_file_1 (lfname, 0) == 0)
      {
--- 543,549 ----
  static int
  lock_if_free (clasher, lfname)
       lock_info_type *clasher;
!      register char *lfname;
  {
    while (lock_file_1 (lfname, 0) == 0)
      {
***************
*** 551,557 ****
  
        if (errno != EEXIST)
        return -1;
!       
        locker = current_lock_owner (clasher, lfname);
        if (locker == 2)
          {
--- 551,557 ----
  
        if (errno != EEXIST)
        return -1;
! 
        locker = current_lock_owner (clasher, lfname);
        if (locker == 2)
          {
***************
*** 634,640 ****
    sprintf (locker, "address@hidden (pid %lu)", lock_info.user, lock_info.host,
             lock_info.pid);
    FREE_LOCK_INFO (lock_info);
!   
    attack = call2 (intern ("ask-user-about-lock"), fn, build_string (locker));
    if (!NILP (attack))
      /* User says take the lock */
--- 634,640 ----
    sprintf (locker, "address@hidden (pid %lu)", lock_info.user, lock_info.host,
             lock_info.pid);
    FREE_LOCK_INFO (lock_info);
! 
    attack = call2 (intern ("ask-user-about-lock"), fn, build_string (locker));
    if (!NILP (attack))
      /* User says take the lock */
***************
*** 691,697 ****
    if (SAVE_MODIFF < MODIFF
        && !NILP (file))
      lock_file (file);
!   return Qnil;    
  }
  
  DEFUN ("unlock-buffer", Funlock_buffer, Sunlock_buffer,
--- 691,697 ----
    if (SAVE_MODIFF < MODIFF
        && !NILP (file))
      lock_file (file);
!   return Qnil;
  }
  
  DEFUN ("unlock-buffer", Funlock_buffer, Sunlock_buffer,




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