/* * lockfile.c: * * Copyright (c) 2008 James McKenzie , * All rights reserved. * */ static char rcsid[] = "$Id$"; /* * $Log$ * Revision 1.9 2008/02/15 23:52:12 james * *** empty log message *** * * Revision 1.8 2008/02/15 20:52:36 james * *** empty log message *** * * Revision 1.7 2008/02/15 19:51:30 james * *** empty log message *** * * Revision 1.6 2008/02/15 19:09:00 james * *** empty log message *** * * Revision 1.5 2008/02/15 18:26:49 james * *** empty log message *** * * Revision 1.4 2008/02/15 18:16:48 james * *** empty log message *** * * Revision 1.3 2008/02/15 18:16:35 james * *** empty log message *** * * Revision 1.2 2008/02/15 16:48:56 james * *** empty log message *** * * Revision 1.1 2008/02/15 15:09:17 james * *** empty log message *** * */ #define LOCK_ASCII #undef LOCK_BINARY #define STALE_CHECK_INTERVAL 10 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "lockfile.h" Filelist * filelist_new (void) { Filelist *fl = (Filelist *) malloc (sizeof (Filelist)); fl->head = NULL; return fl; } void filelist_remove (Filelist * fl, Filelist_ent * fle) { Filelist_ent **ep; for (ep = &fl->head; *ep; ep = &((*ep)->next)) if (fle == *ep) break; if (!*ep) return; *ep = fle->next; free (fle); } void filelist_add (Filelist * fl, char *fn) { Filelist_ent *fle; int i = strlen (fn); if (i >= FILE_LIST_MAX_LEN) return; for (fle = fl->head; fle; fle = fle->next) if (!strcmp (fle->name, fn)) return; fle = malloc (sizeof (Filelist_ent)); strcpy (fle->name, fn); fle->next = fl->head; fl->head = fle; } void filelist_free (Filelist * fl) { while (fl->head) filelist_remove (fl, fl->head); free (fl); } void filelist_print (Filelist * fl, FILE * f) { Filelist_ent *fle; if (!fl) { fprintf (f, "(empty list)\n"); return; } for (fle = fl->head; fle; fle = fle->next) fprintf (f, "%s\n", fle->name); } static int chown_uucp (fd) int fd; { static int uuid = -1, ugid; struct passwd *pw; if (uuid < 0) { if (pw = getpwnam ("uucp")) { uuid = pw->pw_uid; ugid = pw->pw_gid; } else { return -1; } } return fchown (fd, uuid, ugid); } int lockfile_make (char *name) { char buf[1024], tmpfn[1024]; char *ptr; int fd; int i; strcpy (tmpfn, name); ptr = rindex (tmpfn, '/'); if (!ptr) return -1; ptr++; ptr += sprintf (ptr, "LTMP.%d", getpid ()); *ptr = 0; i = sprintf (buf, "%10d\n", getpid ()); unlink (tmpfn); fd = open (tmpfn, O_WRONLY | O_CREAT | O_TRUNC, 0444); if (fd < 0) { unlink (tmpfn); return -1; } write (fd, buf, i); fchmod (fd, 044); if (chown_uucp (fd)) { close (fd); unlink (tmpfn); return -1; } close (fd); if (link (tmpfn, name) < 0) { unlink (tmpfn); return -1; } unlink (tmpfn); return 0; } void lockfile_add_places (Filelist * fl, char *leaf) { char buf[1024]; struct stat stbuf; char *lock_dirs[] = { "/var/lock/uucp", "/var/spool/lock", "/var/spool/uucp", "/etc/locks", "/usr/spool/uucp", "/var/spool/locks", "/usr/spool/lock", "/usr/spool/locks", "/usr/spool/uucp/LCK", "/var/lock" }; int i; for (i = 0; i < (sizeof (lock_dirs) / sizeof (char *)); ++i) { if (stat (lock_dirs[i], &stbuf)) continue; strcpy (buf, lock_dirs[i]); strcat (buf, "/"); strcat (buf, leaf); filelist_add (fl, buf); } } static void do_tedious_mangling (Filelist * fl, char *buf, char *ptr, char inv, int lower) { while (*ptr) { if (lower && (*ptr >= 'A') && (*ptr <= 'Z')) *ptr |= 32; if (*ptr == '/') *ptr = inv; ptr++; } lockfile_add_places (fl, buf); } void lockfile_regularize_and_add (Filelist * fl, char *leaf) { char buf[1024] = "LCK.."; char *ptr; if (*leaf == '/') leaf++; ptr = buf; while (*ptr) ptr++; strcpy (ptr, leaf); do_tedious_mangling (fl, buf, ptr, '_', 0); strcpy (ptr, leaf); do_tedious_mangling (fl, buf, ptr, '_', 1); strcpy (ptr, leaf); do_tedious_mangling (fl, buf, ptr, '.', 0); strcpy (ptr, leaf); do_tedious_mangling (fl, buf, ptr, '.', 1); } void lockfile_add_name_from_path (Filelist * fl, char *file) { char *ptr = file; if (*ptr == '/') ptr++; lockfile_regularize_and_add (fl, ptr); if (!strncmp (ptr, "dev/", 4)) { ptr += 4; lockfile_regularize_and_add (fl, ptr); } } void lockfile_add_name_from_dev (Filelist * fl, dev_t dev) { char buf[1024]; sprintf (buf, "LCK.%03d.%03d", major (dev), minor (dev)); lockfile_add_places (fl, buf); } void lockfile_check_dir_for_dev (Filelist * fl, char *dir, dev_t dev) { char buf[1024]; struct stat ent_stat; struct dirent *de; DIR *d; d = opendir (dir); if (!d) return; while ((de = readdir (d))) { strcpy (buf, dir); strcat (buf, de->d_name); if (stat (buf, &ent_stat)) continue; if (!S_ISCHR (ent_stat.st_mode)) continue; if (ent_stat.st_rdev != dev) continue; lockfile_add_name_from_path (fl, buf); } closedir (d); } Filelist * lockfile_make_list (char *device) { struct stat dev_stat; Filelist *ret = NULL; if (stat (device, &dev_stat)) return ret; if (!S_ISCHR (dev_stat.st_mode)) return ret; ret = filelist_new (); lockfile_add_name_from_dev (ret, dev_stat.st_rdev); lockfile_add_name_from_path (ret, device); lockfile_check_dir_for_dev (ret, "/dev/", dev_stat.st_rdev); lockfile_check_dir_for_dev (ret, "/dev/usb/", dev_stat.st_rdev); lockfile_check_dir_for_dev (ret, "/dev/tts/", dev_stat.st_rdev); return ret; } static void remove_stale_lock (char *path) { int fd; int pid; char apid[20]; int length; fd = open (path, O_RDONLY); if (fd < 0) return; length = read (fd, apid, sizeof (apid) - 1); if (length < 0) length = 0; apid[length] = 0; pid = 0; if (length == sizeof (pid) || sscanf (apid, "%d", &pid) != 1 || pid == 0) { pid = *((int *) apid); #ifdef LOCK_ASCII fprintf (stderr, "compiled with ascii locks, found binary lock file (length=%d, pid=%d)!", length, pid); #endif } #ifdef LOCK_BINARY else { fprintf (stderr, "compiled with binary locks, found ascii lock file (length=%d, pid=%d)!", length, pid); } #endif close (fd); if ((kill (pid, 0) < 0) && (errno == ESRCH)) { fprintf (stderr, "removing stale lock file %s\n", path); unlink (path); } } void lockfile_remove_stale (Filelist * fl) { Filelist_ent *fle; struct stat buf; for (fle = fl->head; fle; fle = fle->next) { if (stat (fle->name, &buf)) continue; remove_stale_lock (fle->name); } } Filelist * lockfile_lock (Filelist * fl) { Filelist *ret; Filelist_ent *fle; ret = filelist_new (); lockfile_remove_stale (fl); for (fle = fl->head; fle; fle = fle->next) { if (lockfile_make (fle->name)) { fprintf (stderr, "Failed to get lockfile %s\n", fle->name); filelist_free (ret); return NULL; } filelist_add (ret, fle->name); } return ret; } void lockfile_unlock (Filelist * fl) { while (fl->head) { unlink (fl->head->name); filelist_remove (fl, fl->head); } } /* If we have a passive lock, check noone has an */ /* active one, returns 1 if he does, 0 if he doesnt */ int serial_lock_check (Serial_lock * l) { Filelist_ent *fle; int locks_found = 0; struct stat buf; struct timeval now, dif; if (l->mode == SERIAL_LOCK_ACTIVE) return 0; for (fle = l->locks_to_check->head; fle; fle = fle->next) { if (!stat (fle->name, &buf)) locks_found++; } if (!locks_found) return 0; gettimeofday (&now, NULL); timersub (&now, &l->last_stale_purge, &dif); if (dif.tv_sec > STALE_CHECK_INTERVAL) { lockfile_remove_stale (l->locks_to_check); l->last_stale_purge = now; } return 1; } void serial_lock_free (Serial_lock * l) { if (!l) return; if (l->locks_held) { lockfile_unlock (l->locks_held); filelist_free (l->locks_held); } if (l->locks_to_check) { filelist_free (l->locks_to_check); } free (l); } Serial_lock * serial_lock_new (char *dev, int mode) { Filelist *fl = lockfile_make_list (dev); Serial_lock *l; if (!fl) return NULL; l = (Serial_lock *) malloc (sizeof (Serial_lock)); l->mode = mode; l->locks_to_check = fl; l->locks_held = NULL; memset (&l->last_stale_purge, 0, sizeof (l->last_stale_purge)); if (mode == SERIAL_LOCK_PASSIVE) return l; l->locks_held = lockfile_lock (l->locks_to_check); if (!l->locks_held) { serial_lock_free (l); return NULL; } return l; } #if 0 int main (int argc, char *argv[]) { Filelist *fl = lockfile_make_list ("/dev/ttyS0"); Filelist *fll; Filelist_ent *fle; filelist_print (fl, stdout); fll = lockfile_lock (fl); filelist_print (fll, stdout); } #endif id='n194' href='#n194'>194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335