Commit | Line | Data |
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8dbbc384 | 1 | /* Copyright (C) 1985, 86, 87, 93, 94, 96 Free Software Foundation, Inc. |
8489eb67 RS |
2 | |
3 | This file is part of GNU Emacs. | |
4 | ||
5 | GNU Emacs is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
32676c08 | 7 | the Free Software Foundation; either version 2, or (at your option) |
8489eb67 RS |
8 | any later version. |
9 | ||
10 | GNU Emacs is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with GNU Emacs; see the file COPYING. If not, write to | |
3b7ad313 EN |
17 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
18 | Boston, MA 02111-1307, USA. */ | |
8489eb67 RS |
19 | |
20 | ||
21 | #include <sys/types.h> | |
22 | #include <sys/stat.h> | |
dfcf069d | 23 | #include <signal.h> |
18160b98 | 24 | #include <config.h> |
bfb61299 JB |
25 | |
26 | #ifdef VMS | |
b350a838 | 27 | #include "vms-pwd.h" |
bfb61299 | 28 | #else |
8489eb67 | 29 | #include <pwd.h> |
8dbbc384 | 30 | #endif /* not VMS */ |
bfb61299 | 31 | |
8489eb67 RS |
32 | #include <sys/file.h> |
33 | #ifdef USG | |
34 | #include <fcntl.h> | |
8dbbc384 | 35 | #include <string.h> |
8489eb67 RS |
36 | #endif /* USG */ |
37 | ||
dfcf069d AS |
38 | #ifdef HAVE_UNISTD_H |
39 | #include <unistd.h> | |
40 | #endif | |
41 | ||
8489eb67 | 42 | #include "lisp.h" |
8489eb67 RS |
43 | #include "buffer.h" |
44 | ||
15e88d21 | 45 | #include <time.h> |
8dbbc384 RS |
46 | #include <errno.h> |
47 | #ifndef errno | |
8489eb67 | 48 | extern int errno; |
79941276 RS |
49 | #endif |
50 | ||
8489eb67 | 51 | #ifdef CLASH_DETECTION |
e788eecc KH |
52 | |
53 | #include <utmp.h> | |
8489eb67 | 54 | |
8dbbc384 RS |
55 | /* The strategy: to lock a file FN, create a symlink .#FN in FN's |
56 | directory, with link data `user@host.pid'. This avoids a single | |
57 | mount (== failure) point for lock files. | |
58 | ||
59 | When the host in the lock data is the current host, we can check if | |
60 | the pid is valid with kill. | |
61 | ||
62 | Otherwise, we could look at a separate file that maps hostnames to | |
63 | reboot times to see if the remote pid can possibly be valid, since we | |
64 | don't want Emacs to have to communicate via pipes or sockets or | |
65 | whatever to other processes, either locally or remotely; rms says | |
66 | that's too unreliable. Hence the separate file, which could | |
67 | theoretically be updated by daemons running separately -- but this | |
68 | whole idea is unimplemented; in practice, at least in our | |
1c4f857c | 69 | environment, it seems such stale locks arise fairly infrequently, and |
8dbbc384 RS |
70 | Emacs' standard methods of dealing with clashes suffice. |
71 | ||
72 | We use symlinks instead of normal files because (1) they can be | |
73 | stored more efficiently on the filesystem, since the kernel knows | |
74 | they will be small, and (2) all the info about the lock can be read | |
75 | in a single system call (readlink). Although we could use regular | |
1c4f857c | 76 | files to be useful on old systems lacking symlinks, nowadays |
8dbbc384 RS |
77 | virtually all such systems are probably single-user anyway, so it |
78 | didn't seem worth the complication. | |
79 | ||
80 | Similarly, we don't worry about a possible 14-character limit on | |
81 | file names, because those are all the same systems that don't have | |
82 | symlinks. | |
83 | ||
84 | This is compatible with the locking scheme used by Interleaf (which | |
85 | has contributed this implementation for Emacs), and was designed by | |
86 | Ethan Jacobson, Kimbo Mundy, and others. | |
87 | ||
88 | --karl@cs.umb.edu/karl@hq.ileaf.com. */ | |
8489eb67 | 89 | |
8dbbc384 | 90 | \f |
15e88d21 RS |
91 | /* Return the time of the last system boot. */ |
92 | ||
93 | static time_t boot_time; | |
94 | ||
95 | static time_t | |
96 | get_boot_time () | |
97 | { | |
bd26d5a3 | 98 | #ifdef BOOT_TIME |
15e88d21 RS |
99 | struct utmp ut, *utp; |
100 | ||
101 | if (boot_time) | |
102 | return boot_time; | |
103 | ||
104 | utmpname ("/var/log/wtmp"); | |
105 | ut.ut_type = BOOT_TIME; | |
106 | utp = getutid (&ut); | |
107 | endutent (); | |
108 | ||
109 | if (!utp) | |
110 | return boot_time = 1; | |
111 | return boot_time = utp->ut_time; | |
bd26d5a3 RS |
112 | #else |
113 | return 0; | |
114 | #endif; | |
15e88d21 RS |
115 | } |
116 | \f | |
8dbbc384 | 117 | /* Here is the structure that stores information about a lock. */ |
32676c08 | 118 | |
8dbbc384 RS |
119 | typedef struct |
120 | { | |
121 | char *user; | |
122 | char *host; | |
9005cb4f | 123 | unsigned long pid; |
15e88d21 | 124 | time_t boot_time; |
8dbbc384 | 125 | } lock_info_type; |
32676c08 | 126 | |
49b6d120 RS |
127 | /* When we read the info back, we might need this much more, |
128 | enough for decimal representation plus null. */ | |
129 | #define LOCK_PID_MAX (4 * sizeof (unsigned long)) | |
32676c08 | 130 | |
8dbbc384 RS |
131 | /* Free the two dynamically-allocated pieces in PTR. */ |
132 | #define FREE_LOCK_INFO(i) do { xfree ((i).user); xfree ((i).host); } while (0) | |
e31fbc7a | 133 | |
e31fbc7a | 134 | |
8dbbc384 RS |
135 | /* Write the name of the lock file for FN into LFNAME. Length will be |
136 | that of FN plus two more for the leading `.#' plus one for the null. */ | |
7b92975f | 137 | #define MAKE_LOCK_NAME(lock, file) \ |
fc932ac6 | 138 | (lock = (char *) alloca (STRING_BYTES (XSTRING (file)) + 2 + 1), \ |
8dbbc384 | 139 | fill_in_lock_file_name (lock, (file))) |
e31fbc7a | 140 | |
8dbbc384 RS |
141 | static void |
142 | fill_in_lock_file_name (lockfile, fn) | |
e31fbc7a RS |
143 | register char *lockfile; |
144 | register Lisp_Object fn; | |
145 | { | |
8dbbc384 RS |
146 | register char *p; |
147 | ||
148 | strcpy (lockfile, XSTRING (fn)->data); | |
149 | ||
150 | /* Shift the nondirectory part of the file name (including the null) | |
151 | right two characters. Here is one of the places where we'd have to | |
152 | do something to support 14-character-max file names. */ | |
153 | for (p = lockfile + strlen (lockfile); p != lockfile && *p != '/'; p--) | |
154 | p[2] = *p; | |
e31fbc7a | 155 | |
8dbbc384 RS |
156 | /* Insert the `.#'. */ |
157 | p[1] = '.'; | |
158 | p[2] = '#'; | |
159 | } | |
e31fbc7a | 160 | |
8dbbc384 RS |
161 | /* Lock the lock file named LFNAME. |
162 | If FORCE is nonzero, we do so even if it is already locked. | |
163 | Return 1 if successful, 0 if not. */ | |
e31fbc7a | 164 | |
8dbbc384 RS |
165 | static int |
166 | lock_file_1 (lfname, force) | |
167 | char *lfname; | |
168 | int force; | |
169 | { | |
170 | register int err; | |
bd26d5a3 | 171 | time_t boot_time; |
662c2ef2 RS |
172 | char *user_name; |
173 | char *host_name; | |
174 | char *lock_info_str; | |
175 | ||
176 | if (STRINGP (Fuser_login_name (Qnil))) | |
266d7a00 | 177 | user_name = (char *)XSTRING (Fuser_login_name (Qnil))->data; |
662c2ef2 RS |
178 | else |
179 | user_name = ""; | |
180 | if (STRINGP (Fsystem_name ())) | |
266d7a00 | 181 | host_name = (char *)XSTRING (Fsystem_name ())->data; |
662c2ef2 RS |
182 | else |
183 | host_name = ""; | |
266d7a00 | 184 | lock_info_str = (char *)alloca (strlen (user_name) + strlen (host_name) |
15e88d21 | 185 | + LOCK_PID_MAX + 5); |
8dbbc384 | 186 | |
bd26d5a3 RS |
187 | boot_time = get_boot_time (); |
188 | if (boot_time) | |
189 | sprintf (lock_info_str, "%s@%s.%lu:%lu", user_name, host_name, | |
190 | (unsigned long) getpid (), (unsigned long) boot_time); | |
191 | else | |
192 | sprintf (lock_info_str, "%s@%s.%lu", user_name, host_name, | |
193 | (unsigned long) getpid ()); | |
8dbbc384 RS |
194 | |
195 | err = symlink (lock_info_str, lfname); | |
196 | if (errno == EEXIST && force) | |
e31fbc7a | 197 | { |
8dbbc384 RS |
198 | unlink (lfname); |
199 | err = symlink (lock_info_str, lfname); | |
e31fbc7a | 200 | } |
e31fbc7a | 201 | |
8dbbc384 RS |
202 | return err == 0; |
203 | } | |
e31fbc7a | 204 | |
32676c08 | 205 | |
8dbbc384 RS |
206 | \f |
207 | /* Return 0 if nobody owns the lock file LFNAME or the lock is obsolete, | |
208 | 1 if another process owns it (and set OWNER (if non-null) to info), | |
209 | 2 if the current process owns it, | |
210 | or -1 if something is wrong with the locking mechanism. */ | |
e31fbc7a | 211 | |
8dbbc384 RS |
212 | static int |
213 | current_lock_owner (owner, lfname) | |
214 | lock_info_type *owner; | |
215 | char *lfname; | |
32676c08 | 216 | { |
8dbbc384 RS |
217 | #ifndef index |
218 | extern char *rindex (), *index (); | |
219 | #endif | |
220 | int o, p, len, ret; | |
221 | int local_owner = 0; | |
15e88d21 | 222 | char *at, *dot, *colon; |
8dbbc384 RS |
223 | char *lfinfo = 0; |
224 | int bufsize = 50; | |
225 | /* Read arbitrarily-long contents of symlink. Similar code in | |
226 | file-symlink-p in fileio.c. */ | |
227 | do | |
228 | { | |
229 | bufsize *= 2; | |
230 | lfinfo = (char *) xrealloc (lfinfo, bufsize); | |
231 | len = readlink (lfname, lfinfo, bufsize); | |
232 | } | |
233 | while (len >= bufsize); | |
234 | ||
235 | /* If nonexistent lock file, all is well; otherwise, got strange error. */ | |
236 | if (len == -1) | |
237 | { | |
238 | xfree (lfinfo); | |
239 | return errno == ENOENT ? 0 : -1; | |
240 | } | |
32676c08 | 241 | |
8dbbc384 RS |
242 | /* Link info exists, so `len' is its length. Null terminate. */ |
243 | lfinfo[len] = 0; | |
244 | ||
245 | /* Even if the caller doesn't want the owner info, we still have to | |
246 | read it to determine return value, so allocate it. */ | |
247 | if (!owner) | |
248 | { | |
3609a53b | 249 | owner = (lock_info_type *) alloca (sizeof (lock_info_type)); |
8dbbc384 RS |
250 | local_owner = 1; |
251 | } | |
252 | ||
15e88d21 | 253 | /* Parse USER@HOST.PID:BOOT_TIME. If can't parse, return -1. */ |
8dbbc384 RS |
254 | /* The USER is everything before the first @. */ |
255 | at = index (lfinfo, '@'); | |
256 | dot = rindex (lfinfo, '.'); | |
15e88d21 RS |
257 | if (!at || !dot) |
258 | { | |
259 | xfree (lfinfo); | |
260 | return -1; | |
261 | } | |
8dbbc384 RS |
262 | len = at - lfinfo; |
263 | owner->user = (char *) xmalloc (len + 1); | |
264 | strncpy (owner->user, lfinfo, len); | |
265 | owner->user[len] = 0; | |
266 | ||
15e88d21 | 267 | /* The PID is everything from the last `.' to the `:'. */ |
8dbbc384 | 268 | owner->pid = atoi (dot + 1); |
15e88d21 RS |
269 | colon = dot; |
270 | while (*colon && *colon != ':') | |
271 | colon++; | |
272 | /* After the `:', if there is one, comes the boot time. */ | |
273 | if (*colon == ':') | |
274 | owner->boot_time = atoi (colon + 1); | |
275 | else | |
276 | owner->boot_time = 0; | |
32676c08 | 277 | |
8dbbc384 RS |
278 | /* The host is everything in between. */ |
279 | len = dot - at - 1; | |
280 | owner->host = (char *) xmalloc (len + 1); | |
281 | strncpy (owner->host, at + 1, len); | |
282 | owner->host[len] = 0; | |
32676c08 | 283 | |
8dbbc384 RS |
284 | /* We're done looking at the link info. */ |
285 | xfree (lfinfo); | |
286 | ||
287 | /* On current host? */ | |
662c2ef2 RS |
288 | if (STRINGP (Fsystem_name ()) |
289 | && strcmp (owner->host, XSTRING (Fsystem_name ())->data) == 0) | |
32676c08 | 290 | { |
8dbbc384 RS |
291 | if (owner->pid == getpid ()) |
292 | ret = 2; /* We own it. */ | |
72dcef0e | 293 | else if (owner->pid > 0 |
15e88d21 RS |
294 | && (kill (owner->pid, 0) >= 0 || errno == EPERM) |
295 | && (owner->boot_time == 0 | |
296 | || owner->boot_time == get_boot_time ())) | |
8dbbc384 | 297 | ret = 1; /* An existing process on this machine owns it. */ |
8dbbc384 RS |
298 | /* The owner process is dead or has a strange pid (<=0), so try to |
299 | zap the lockfile. */ | |
72dcef0e | 300 | else if (unlink (lfname) < 0) |
8dbbc384 | 301 | ret = -1; |
72dcef0e RS |
302 | else |
303 | ret = 0; | |
32676c08 | 304 | } |
8dbbc384 RS |
305 | else |
306 | { /* If we wanted to support the check for stale locks on remote machines, | |
307 | here's where we'd do it. */ | |
308 | ret = 1; | |
309 | } | |
310 | ||
311 | /* Avoid garbage. */ | |
312 | if (local_owner || ret <= 0) | |
313 | { | |
314 | FREE_LOCK_INFO (*owner); | |
315 | } | |
316 | return ret; | |
32676c08 JB |
317 | } |
318 | ||
8dbbc384 RS |
319 | \f |
320 | /* Lock the lock named LFNAME if possible. | |
321 | Return 0 in that case. | |
322 | Return positive if some other process owns the lock, and info about | |
323 | that process in CLASHER. | |
324 | Return -1 if cannot lock for any other reason. */ | |
8489eb67 | 325 | |
8dbbc384 RS |
326 | static int |
327 | lock_if_free (clasher, lfname) | |
328 | lock_info_type *clasher; | |
329 | register char *lfname; | |
330 | { | |
c6c0c4b1 | 331 | if (lock_file_1 (lfname, 0) == 0) |
8dbbc384 RS |
332 | { |
333 | int locker; | |
e0e0205b | 334 | |
8dbbc384 RS |
335 | if (errno != EEXIST) |
336 | return -1; | |
337 | ||
338 | locker = current_lock_owner (clasher, lfname); | |
339 | if (locker == 2) | |
340 | { | |
341 | FREE_LOCK_INFO (*clasher); | |
342 | return 0; /* We ourselves locked it. */ | |
343 | } | |
344 | else if (locker == 1) | |
345 | return 1; /* Someone else has it. */ | |
8dbbc384 | 346 | |
c6c0c4b1 | 347 | return -1; /* Something's wrong. */ |
8dbbc384 RS |
348 | } |
349 | return 0; | |
8489eb67 RS |
350 | } |
351 | ||
8dbbc384 | 352 | /* lock_file locks file FN, |
8489eb67 RS |
353 | meaning it serves notice on the world that you intend to edit that file. |
354 | This should be done only when about to modify a file-visiting | |
355 | buffer previously unmodified. | |
8dbbc384 | 356 | Do not (normally) call this for a buffer already modified, |
8489eb67 RS |
357 | as either the file is already locked, or the user has already |
358 | decided to go ahead without locking. | |
359 | ||
8dbbc384 | 360 | When this returns, either the lock is locked for us, |
8489eb67 RS |
361 | or the user has said to go ahead without locking. |
362 | ||
8dbbc384 | 363 | If the file is locked by someone else, this calls |
8489eb67 | 364 | ask-user-about-lock (a Lisp function) with two arguments, |
8dbbc384 | 365 | the file name and info about the user who did the locking. |
8489eb67 RS |
366 | This function can signal an error, or return t meaning |
367 | take away the lock, or return nil meaning ignore the lock. */ | |
368 | ||
8489eb67 RS |
369 | void |
370 | lock_file (fn) | |
8dbbc384 | 371 | register Lisp_Object fn; |
8489eb67 | 372 | { |
5383bc6d | 373 | register Lisp_Object attack, orig_fn; |
8dbbc384 RS |
374 | register char *lfname, *locker; |
375 | lock_info_type lock_info; | |
8489eb67 | 376 | |
5383bc6d | 377 | orig_fn = fn; |
1e89de84 KH |
378 | fn = Fexpand_file_name (fn, Qnil); |
379 | ||
8dbbc384 | 380 | /* Create the name of the lock-file for file fn */ |
7b92975f | 381 | MAKE_LOCK_NAME (lfname, fn); |
8489eb67 | 382 | |
32676c08 JB |
383 | /* See if this file is visited and has changed on disk since it was |
384 | visited. */ | |
8489eb67 | 385 | { |
a57bc488 | 386 | register Lisp_Object subject_buf; |
5383bc6d | 387 | subject_buf = get_truename_buffer (orig_fn); |
265a9e55 JB |
388 | if (!NILP (subject_buf) |
389 | && NILP (Fverify_visited_file_modtime (subject_buf)) | |
390 | && !NILP (Ffile_exists_p (fn))) | |
8489eb67 RS |
391 | call1 (intern ("ask-user-about-supersession-threat"), fn); |
392 | } | |
393 | ||
394 | /* Try to lock the lock. */ | |
8dbbc384 RS |
395 | if (lock_if_free (&lock_info, lfname) <= 0) |
396 | /* Return now if we have locked it, or if lock creation failed */ | |
8489eb67 RS |
397 | return; |
398 | ||
399 | /* Else consider breaking the lock */ | |
266d7a00 RS |
400 | locker = (char *) alloca (strlen (lock_info.user) + strlen (lock_info.host) |
401 | + LOCK_PID_MAX + 9); | |
79e51eeb | 402 | sprintf (locker, "%s@%s (pid %lu)", lock_info.user, lock_info.host, |
8dbbc384 RS |
403 | lock_info.pid); |
404 | FREE_LOCK_INFO (lock_info); | |
405 | ||
406 | attack = call2 (intern ("ask-user-about-lock"), fn, build_string (locker)); | |
265a9e55 | 407 | if (!NILP (attack)) |
8489eb67 RS |
408 | /* User says take the lock */ |
409 | { | |
8dbbc384 | 410 | lock_file_1 (lfname, 1); |
8489eb67 RS |
411 | return; |
412 | } | |
413 | /* User says ignore the lock */ | |
414 | } | |
415 | ||
8489eb67 RS |
416 | void |
417 | unlock_file (fn) | |
418 | register Lisp_Object fn; | |
419 | { | |
420 | register char *lfname; | |
421 | ||
1e89de84 KH |
422 | fn = Fexpand_file_name (fn, Qnil); |
423 | ||
7b92975f | 424 | MAKE_LOCK_NAME (lfname, fn); |
8489eb67 | 425 | |
8dbbc384 | 426 | if (current_lock_owner (0, lfname) == 2) |
8489eb67 | 427 | unlink (lfname); |
8489eb67 RS |
428 | } |
429 | ||
430 | void | |
431 | unlock_all_files () | |
432 | { | |
433 | register Lisp_Object tail; | |
434 | register struct buffer *b; | |
435 | ||
4e6c9d9e | 436 | for (tail = Vbuffer_alist; GC_CONSP (tail); tail = XCONS (tail)->cdr) |
8489eb67 RS |
437 | { |
438 | b = XBUFFER (XCONS (XCONS (tail)->car)->cdr); | |
5757b805 | 439 | if (STRINGP (b->file_truename) && BUF_SAVE_MODIFF (b) < BUF_MODIFF (b)) |
1c343051 KH |
440 | { |
441 | register char *lfname; | |
442 | ||
443 | MAKE_LOCK_NAME (lfname, b->file_truename); | |
444 | ||
445 | if (current_lock_owner (0, lfname) == 2) | |
446 | unlink (lfname); | |
447 | } | |
8489eb67 RS |
448 | } |
449 | } | |
8489eb67 RS |
450 | \f |
451 | DEFUN ("lock-buffer", Flock_buffer, Slock_buffer, | |
452 | 0, 1, 0, | |
453 | "Lock FILE, if current buffer is modified.\n\ | |
454 | FILE defaults to current buffer's visited file,\n\ | |
455 | or else nothing is done if current buffer isn't visiting a file.") | |
e9319ef2 EN |
456 | (file) |
457 | Lisp_Object file; | |
8489eb67 | 458 | { |
e9319ef2 EN |
459 | if (NILP (file)) |
460 | file = current_buffer->file_truename; | |
8489eb67 | 461 | else |
e9319ef2 | 462 | CHECK_STRING (file, 0); |
6a140159 | 463 | if (SAVE_MODIFF < MODIFF |
e9319ef2 EN |
464 | && !NILP (file)) |
465 | lock_file (file); | |
8489eb67 RS |
466 | return Qnil; |
467 | } | |
468 | ||
469 | DEFUN ("unlock-buffer", Funlock_buffer, Sunlock_buffer, | |
470 | 0, 0, 0, | |
471 | "Unlock the file visited in the current buffer,\n\ | |
472 | if it should normally be locked.") | |
473 | () | |
474 | { | |
6a140159 | 475 | if (SAVE_MODIFF < MODIFF |
5757b805 RS |
476 | && STRINGP (current_buffer->file_truename)) |
477 | unlock_file (current_buffer->file_truename); | |
8489eb67 RS |
478 | return Qnil; |
479 | } | |
480 | ||
8489eb67 RS |
481 | /* Unlock the file visited in buffer BUFFER. */ |
482 | ||
d07e0802 | 483 | void |
8489eb67 RS |
484 | unlock_buffer (buffer) |
485 | struct buffer *buffer; | |
486 | { | |
6a140159 | 487 | if (BUF_SAVE_MODIFF (buffer) < BUF_MODIFF (buffer) |
5757b805 RS |
488 | && STRINGP (buffer->file_truename)) |
489 | unlock_file (buffer->file_truename); | |
8489eb67 RS |
490 | } |
491 | ||
492 | DEFUN ("file-locked-p", Ffile_locked_p, Sfile_locked_p, 0, 1, 0, | |
493 | "Return nil if the FILENAME is not locked,\n\ | |
494 | t if it is locked by you, else a string of the name of the locker.") | |
e9319ef2 EN |
495 | (filename) |
496 | Lisp_Object filename; | |
8489eb67 | 497 | { |
8dbbc384 | 498 | Lisp_Object ret; |
8489eb67 RS |
499 | register char *lfname; |
500 | int owner; | |
8dbbc384 | 501 | lock_info_type locker; |
8489eb67 | 502 | |
e9319ef2 | 503 | filename = Fexpand_file_name (filename, Qnil); |
8489eb67 | 504 | |
e9319ef2 | 505 | MAKE_LOCK_NAME (lfname, filename); |
8489eb67 | 506 | |
8dbbc384 | 507 | owner = current_lock_owner (&locker, lfname); |
8489eb67 | 508 | if (owner <= 0) |
8dbbc384 RS |
509 | ret = Qnil; |
510 | else if (owner == 2) | |
511 | ret = Qt; | |
512 | else | |
513 | ret = build_string (locker.user); | |
514 | ||
515 | if (owner > 0) | |
516 | FREE_LOCK_INFO (locker); | |
517 | ||
518 | return ret; | |
8489eb67 | 519 | } |
32676c08 JB |
520 | \f |
521 | /* Initialization functions. */ | |
522 | ||
dfcf069d | 523 | void |
8489eb67 RS |
524 | syms_of_filelock () |
525 | { | |
526 | defsubr (&Sunlock_buffer); | |
527 | defsubr (&Slock_buffer); | |
528 | defsubr (&Sfile_locked_p); | |
529 | } | |
530 | ||
531 | #endif /* CLASH_DETECTION */ |