-/* Copyright (C) 1985, 86, 87, 93, 94, 96 Free Software Foundation, Inc.
+/* Lock files for editing.
+ Copyright (C) 1985, 86, 87, 93, 94, 96, 98, 1999 Free Software Foundation, Inc.
This file is part of GNU Emacs.
Boston, MA 02111-1307, USA. */
+#include <config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>
-#include <config.h>
+#include <stdio.h>
#ifdef VMS
#include "vms-pwd.h"
#endif /* not VMS */
#include <sys/file.h>
-#ifdef USG
+#ifdef HAVE_FCNTL_H
#include <fcntl.h>
+#endif
+#ifdef HAVE_STRING_H
#include <string.h>
-#endif /* USG */
+#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
+#ifdef __FreeBSD__
+#include <sys/sysctl.h>
+#endif /* __FreeBSD__ */
+
+#include <errno.h>
+#ifndef errno
+extern int errno;
+#endif
+
#include "lisp.h"
#include "buffer.h"
#include "charset.h"
#include "coding.h"
#include "systime.h"
-#include <time.h>
-#include <errno.h>
-#ifndef errno
-extern int errno;
-#endif
+/* The directory for writing temporary files. */
+
+Lisp_Object Vtemporary_file_directory;
#ifdef CLASH_DETECTION
#include <utmp.h>
+
+/* A file whose last-modified time is just after the most recent boot.
+ Define this to be NULL to disable checking for this file. */
+#ifndef BOOT_TIME_FILE
+#define BOOT_TIME_FILE "/var/run/random-seed"
+#endif
+
+#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 `user@host.pid'. This avoids a single
/* Return the time of the last system boot. */
static time_t boot_time;
+static int boot_time_initialized;
extern Lisp_Object Vshell_file_name;
+#ifdef BOOT_TIME
+static void get_boot_time_1 P_ ((char *, int));
+#endif
+
static time_t
get_boot_time ()
{
-#ifdef BOOT_TIME
- struct utmp ut, *utp;
- int fd;
- EMACS_TIME time_before, after;
+#if defined (BOOT_TIME) && ! defined (NO_WTMP_FILE)
int counter;
+#endif
- if (boot_time)
+ if (boot_time_initialized)
return boot_time;
+ boot_time_initialized = 1;
- EMACS_GET_TIME (time_before);
-
- /* Try calculating the last boot time
- from the uptime as obtained from /proc/uptime. */
+#if defined (CTL_KERN) && defined (KERN_BOOTTIME)
+ {
+ int mib[2];
+ size_t size;
+ struct timeval boottime_val;
+
+ mib[0] = CTL_KERN;
+ mib[1] = KERN_BOOTTIME;
+ size = sizeof (boottime_val);
+
+ if (sysctl (mib, 2, &boottime_val, &size, NULL, 0) >= 0)
+ {
+ boot_time = boottime_val.tv_sec;
+ return boot_time;
+ }
+ }
+#endif /* defined (CTL_KERN) && defined (KERN_BOOTTIME) */
- while ((fd = open ("/proc/uptime", O_RDONLY)) >= 0)
+ if (BOOT_TIME_FILE)
{
- char buf[BUFSIZ];
- int res;
- double upsecs;
- time_t uptime;
-
- read (fd, buf, BUFSIZ);
- close (fd);
-
- res = sscanf (buf, "%lf", &upsecs);
-
- /* If the current time did not tick while we were getting the
- uptime, we have a valid result. */
- EMACS_GET_TIME (after);
- if (res == 1 && EMACS_SECS (after) == EMACS_SECS (time_before))
+ struct stat st;
+ if (stat (BOOT_TIME_FILE, &st) == 0)
{
- boot_time = EMACS_SECS (time_before) - (time_t) upsecs;
+ boot_time = st.st_mtime;
return boot_time;
}
-
- /* Otherwise, try again to read the uptime. */
- time_before = after;
}
+#if defined (BOOT_TIME) && ! defined (NO_WTMP_FILE)
+#ifndef CANNOT_DUMP
+ /* The utmp routines maintain static state.
+ Don't touch that state unless we are initialized,
+ since it might not survive dumping. */
+ if (! initialized)
+ return boot_time;
+#endif /* not CANNOT_DUMP */
+
+ /* Try to get boot time from utmp before wtmp,
+ since utmp is typically much smaller than wtmp.
+ Passing a null pointer causes get_boot_time_1
+ to inspect the default file, namely utmp. */
+ get_boot_time_1 ((char *) 0, 0);
+ if (boot_time)
+ return boot_time;
+
/* Try to get boot time from the current wtmp file. */
- get_boot_time_1 ("/var/log/wtmp");
+ get_boot_time_1 (WTMP_FILE, 1);
/* If we did not find a boot time in wtmp, look at wtmp, and so on. */
- for (counter = 0; counter < 20 && boot_time == 1; counter++)
+ for (counter = 0; counter < 20 && ! boot_time; counter++)
{
char cmd_string[100];
Lisp_Object tempname, filename;
filename = Qnil;
- sprintf (cmd_string, "/var/log/wtmp.%d", counter);
+ sprintf (cmd_string, "%s.%d", WTMP_FILE, counter);
tempname = build_string (cmd_string);
- if (! NILP (Ffile_exists_p (filename)))
+ if (! NILP (Ffile_exists_p (tempname)))
filename = tempname;
else
{
- sprintf (cmd_string, "/var/log/wtmp.%d.gz", counter);
+ sprintf (cmd_string, "%s.%d.gz", WTMP_FILE, counter);
tempname = build_string (cmd_string);
if (! NILP (Ffile_exists_p (tempname)))
{
Lisp_Object args[6];
- tempname = Fmake_temp_name (build_string ("wtmp"));
+
+ /* The utmp functions on mescaline.gnu.org accept only
+ file names up to 8 characters long. Choose a 2
+ character long prefix, and call make_temp_file with
+ second arg non-zero, so that it will add not more
+ than 6 characters to the prefix. */
+ tempname = Fexpand_file_name (build_string ("wt"),
+ Vtemporary_file_directory);
+ tempname = make_temp_name (tempname, 1);
args[0] = Vshell_file_name;
args[1] = Qnil;
args[2] = Qnil;
args[3] = Qnil;
args[4] = build_string ("-c");
- sprintf (cmd_string, "gunzip < /var/log/wtmp.%d.gz > %s",
- counter, XSTRING (tempname)->data);
+ sprintf (cmd_string, "gunzip < %s.%d.gz > %s",
+ WTMP_FILE, counter, XSTRING (tempname)->data);
args[5] = build_string (cmd_string);
Fcall_process (6, args);
filename = tempname;
if (! NILP (filename))
{
- get_boot_time_1 (XSTRING (filename)->data);
+ get_boot_time_1 (XSTRING (filename)->data, 1);
if (delete_flag)
unlink (XSTRING (filename)->data);
}
#ifdef BOOT_TIME
/* Try to get the boot time from wtmp file FILENAME.
This succeeds if that file contains a reboot record.
- Success is indicated by setting BOOT_TIME. */
-get_boot_time_1 (filename)
+ If FILENAME is zero, use the same file as before;
+ if no FILENAME has ever been specified, this is the utmp file.
+ Use the newest reboot record if NEWEST is nonzero,
+ the first reboot record otherwise.
+ Ignore all reboot records on or before BOOT_TIME.
+ Success is indicated by setting BOOT_TIME to a larger value. */
+
+void
+get_boot_time_1 (filename, newest)
char *filename;
+ int newest;
{
struct utmp ut, *utp;
+ int desc;
+
+ if (filename)
+ {
+ /* On some versions of IRIX, opening a nonexistent file name
+ is likely to crash in the utmp routines. */
+ desc = emacs_open (filename, O_RDONLY, 0);
+ if (desc < 0)
+ return;
+
+ emacs_close (desc);
+
+ utmpname (filename);
+ }
- utmpname (filename);
setutent ();
+
while (1)
{
/* Find the next reboot record. */
break;
/* Compare reboot times and use the newest one. */
if (utp->ut_time > boot_time)
- boot_time = utp->ut_time;
+ {
+ boot_time = utp->ut_time;
+ if (! newest)
+ break;
+ }
/* Advance on element in the file
so that getutid won't repeat the same one. */
utp = getutent ();
/* Write the name of the lock file for FN into LFNAME. Length will be
- that of FN plus two more for the leading `.#' plus one for the null. */
+ that of FN plus two more for the leading `.#' plus 1 for the
+ trailing period plus one for the digit after it plus one for the
+ null. */
#define MAKE_LOCK_NAME(lock, file) \
- (lock = (char *) alloca (STRING_BYTES (XSTRING (file)) + 2 + 1), \
+ (lock = (char *) alloca (STRING_BYTES (XSTRING (file)) + 2 + 1 + 1 + 1), \
fill_in_lock_file_name (lock, (file)))
static void
register Lisp_Object fn;
{
register char *p;
+ struct stat st;
+ int count = 0;
strcpy (lockfile, XSTRING (fn)->data);
/* Insert the `.#'. */
p[1] = '.';
p[2] = '#';
+
+ p = p + strlen (p);
+
+ while (lstat (lockfile, &st) == 0 && !S_ISLNK (st.st_mode))
+ {
+ if (count > 9)
+ {
+ *p = '\0';
+ return;
+ }
+ sprintf (p, ".%d", count++);
+ }
}
/* Lock the lock file named LFNAME.
#ifndef index
extern char *rindex (), *index ();
#endif
- int o, p, len, ret;
+ int len, ret;
int local_owner = 0;
char *at, *dot, *colon;
char *lfinfo = 0;
lock_info_type *clasher;
register char *lfname;
{
- if (lock_file_1 (lfname, 0) == 0)
+ while (lock_file_1 (lfname, 0) == 0)
{
int locker;
}
else if (locker == 1)
return 1; /* Someone else has it. */
+ else if (locker == -1)
+ return -1; /* current_lock_owner returned strange error. */
- return -1; /* Something's wrong. */
+ /* We deleted a stale lock; try again to lock the file. */
}
return 0;
}
register Lisp_Object attack, orig_fn, encoded_fn;
register char *lfname, *locker;
lock_info_type lock_info;
+ struct gcpro gcpro1;
+
+ /* Don't do locking while dumping Emacs.
+ Uncompressing wtmp files uses call-process, which does not work
+ in an uninitialized Emacs. */
+ if (! NILP (Vpurify_flag))
+ return;
orig_fn = fn;
+ GCPRO1 (fn);
fn = Fexpand_file_name (fn, Qnil);
encoded_fn = ENCODE_FILE (fn);
visited. */
{
register Lisp_Object subject_buf;
- struct gcpro gcpro1;
subject_buf = get_truename_buffer (orig_fn);
- GCPRO1 (fn);
if (!NILP (subject_buf)
&& NILP (Fverify_visited_file_modtime (subject_buf))
&& !NILP (Ffile_exists_p (fn)))
call1 (intern ("ask-user-about-supersession-threat"), fn);
- UNGCPRO;
}
+ UNGCPRO;
/* Try to lock the lock. */
if (lock_if_free (&lock_info, lfname) <= 0)
register Lisp_Object tail;
register struct buffer *b;
- for (tail = Vbuffer_alist; GC_CONSP (tail); tail = XCONS (tail)->cdr)
+ for (tail = Vbuffer_alist; GC_CONSP (tail); tail = XCDR (tail))
{
- b = XBUFFER (XCONS (XCONS (tail)->car)->cdr);
+ b = XBUFFER (XCDR (XCAR (tail)));
if (STRINGP (b->file_truename) && BUF_SAVE_MODIFF (b) < BUF_MODIFF (b))
{
register char *lfname;
unlock_file (buffer->file_truename);
}
-DEFUN ("file-locked-p", Ffile_locked_p, Sfile_locked_p, 0, 1, 0,
+DEFUN ("file-locked-p", Ffile_locked_p, Sfile_locked_p, 1, 1, 0,
"Return nil if the FILENAME is not locked,\n\
t if it is locked by you, else a string of the name of the locker.")
(filename)
\f
/* Initialization functions. */
+void
+init_filelock ()
+{
+ boot_time = 0;
+ boot_time_initialized = 0;
+}
+
void
syms_of_filelock ()
{
+ DEFVAR_LISP ("temporary-file-directory", &Vtemporary_file_directory,
+ "The directory for writing temporary files.");
+ Vtemporary_file_directory = Qnil;
+
defsubr (&Sunlock_buffer);
defsubr (&Slock_buffer);
defsubr (&Sfile_locked_p);
HCoop / bpt / emacs.git / blobdiff