#include <sys/types.h>
#include <sys/stat.h>
+#include <signal.h>
#include <config.h>
#ifdef VMS
#include <string.h>
#endif /* USG */
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
#include "lisp.h"
#include "buffer.h"
+#include "charset.h"
+#include "coding.h"
+#include <time.h>
#include <errno.h>
#ifndef errno
extern int errno;
#endif
#ifdef CLASH_DETECTION
+
+#include <utmp.h>
/* 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
--karl@cs.umb.edu/karl@hq.ileaf.com. */
+\f
+/* Return the time of the last system boot. */
+
+static time_t boot_time;
+
+static time_t
+get_boot_time ()
+{
+#ifdef BOOT_TIME
+ struct utmp ut, *utp;
+
+ if (boot_time)
+ return boot_time;
+
+ utmpname ("/var/log/wtmp");
+ setutent ();
+ boot_time = 1;
+ while (1)
+ {
+ /* Find the next reboot record. */
+ ut.ut_type = BOOT_TIME;
+ utp = getutid (&ut);
+ if (! utp)
+ break;
+ /* Compare reboot times and use the newest one. */
+ if (utp->ut_time > boot_time)
+ boot_time = utp->ut_time;
+ /* Advance on element in the file
+ so that getutid won't repeat the same one. */
+ utp = getutent ();
+ if (! utp)
+ break;
+ }
+ endutent ();
+
+ return boot_time;
+#else
+ return 0;
+#endif
+}
\f
/* Here is the structure that stores information about a lock. */
char *user;
char *host;
unsigned long pid;
+ time_t boot_time;
} lock_info_type;
/* When we read the info back, we might need this much more,
/* 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. */
#define MAKE_LOCK_NAME(lock, file) \
- (lock = (char *) alloca (XSTRING (file)->size + 2 + 1), \
+ (lock = (char *) alloca (STRING_BYTES (XSTRING (file)) + 2 + 1), \
fill_in_lock_file_name (lock, (file)))
static void
int force;
{
register int err;
+ time_t boot_time;
char *user_name;
char *host_name;
char *lock_info_str;
else
host_name = "";
lock_info_str = (char *)alloca (strlen (user_name) + strlen (host_name)
- + LOCK_PID_MAX + 5);
+ + LOCK_PID_MAX + 5);
- sprintf (lock_info_str, "%s@%s.%lu", user_name, host_name,
- (unsigned long) getpid ());
+ boot_time = get_boot_time ();
+ if (boot_time)
+ sprintf (lock_info_str, "%s@%s.%lu:%lu", user_name, host_name,
+ (unsigned long) getpid (), (unsigned long) boot_time);
+ else
+ sprintf (lock_info_str, "%s@%s.%lu", user_name, host_name,
+ (unsigned long) getpid ());
err = symlink (lock_info_str, lfname);
if (errno == EEXIST && force)
#endif
int o, p, len, ret;
int local_owner = 0;
- char *at, *dot;
+ char *at, *dot, *colon;
char *lfinfo = 0;
int bufsize = 50;
/* Read arbitrarily-long contents of symlink. Similar code in
local_owner = 1;
}
- /* Parse USER@HOST.PID. If can't parse, return -1. */
+ /* Parse USER@HOST.PID:BOOT_TIME. If can't parse, return -1. */
/* The USER is everything before the first @. */
at = index (lfinfo, '@');
dot = rindex (lfinfo, '.');
- if (!at || !dot) {
- xfree (lfinfo);
- return -1;
- }
+ if (!at || !dot)
+ {
+ xfree (lfinfo);
+ return -1;
+ }
len = at - lfinfo;
owner->user = (char *) xmalloc (len + 1);
strncpy (owner->user, lfinfo, len);
owner->user[len] = 0;
- /* The PID is everything after the last `.'. */
+ /* The PID is everything from the last `.' to the `:'. */
owner->pid = atoi (dot + 1);
+ colon = dot;
+ while (*colon && *colon != ':')
+ colon++;
+ /* After the `:', if there is one, comes the boot time. */
+ if (*colon == ':')
+ owner->boot_time = atoi (colon + 1);
+ else
+ owner->boot_time = 0;
/* The host is everything in between. */
len = dot - at - 1;
if (owner->pid == getpid ())
ret = 2; /* We own it. */
else if (owner->pid > 0
- && (kill (owner->pid, 0) >= 0 || errno == EPERM))
+ && (kill (owner->pid, 0) >= 0 || errno == EPERM)
+ && (owner->boot_time == 0
+ || owner->boot_time == get_boot_time ()))
ret = 1; /* An existing process on this machine owns it. */
/* The owner process is dead or has a strange pid (<=0), so try to
zap the lockfile. */
void
lock_file (fn)
- register Lisp_Object fn;
+ Lisp_Object fn;
{
- register Lisp_Object attack, orig_fn;
+ register Lisp_Object attack, orig_fn, encoded_fn;
register char *lfname, *locker;
lock_info_type lock_info;
orig_fn = fn;
fn = Fexpand_file_name (fn, Qnil);
+ encoded_fn = ENCODE_FILE (fn);
/* Create the name of the lock-file for file fn */
- MAKE_LOCK_NAME (lfname, fn);
+ MAKE_LOCK_NAME (lfname, encoded_fn);
/* See if this file is visited and has changed on disk since it was
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;
}
/* Try to lock the lock. */
register char *lfname;
fn = Fexpand_file_name (fn, Qnil);
+ fn = ENCODE_FILE (fn);
MAKE_LOCK_NAME (lfname, fn);
/* Unlock the file visited in buffer BUFFER. */
+void
unlock_buffer (buffer)
struct buffer *buffer;
{
return ret;
}
-
\f
/* Initialization functions. */
+void
syms_of_filelock ()
{
defsubr (&Sunlock_buffer);