| File: | src/gnu/usr.bin/cvs/src/lock.c |
| Warning: | line 907, column 5 Value stored to 'err' is never read |
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| 1 | /* |
| 2 | * Copyright (c) 1992, Brian Berliner and Jeff Polk |
| 3 | * Copyright (c) 1989-1992, Brian Berliner |
| 4 | * |
| 5 | * You may distribute under the terms of the GNU General Public License as |
| 6 | * specified in the README file that comes with the CVS source distribution. |
| 7 | * |
| 8 | * Set Lock |
| 9 | * |
| 10 | * Lock file support for CVS. |
| 11 | */ |
| 12 | |
| 13 | /* The node Concurrency in doc/cvs.texinfo has a brief introduction to |
| 14 | how CVS locks function, and some of the user-visible consequences of |
| 15 | their existence. Here is a summary of why they exist (and therefore, |
| 16 | the consequences of hacking CVS to read a repository without creating |
| 17 | locks): |
| 18 | |
| 19 | There are two uses. One is the ability to prevent there from being |
| 20 | two writers at the same time. This is necessary for any number of |
| 21 | reasons (fileattr code, probably others). Commit needs to lock the |
| 22 | whole tree so that nothing happens between the up-to-date check and |
| 23 | the actual checkin. |
| 24 | |
| 25 | The second use is the ability to ensure that there is not a writer |
| 26 | and a reader at the same time (several readers are allowed). Reasons |
| 27 | for this are: |
| 28 | |
| 29 | * Readlocks ensure that once CVS has found a collection of rcs |
| 30 | files using Find_Names, the files will still exist when it reads |
| 31 | them (they may have moved in or out of the attic). |
| 32 | |
| 33 | * Readlocks provide some modicum of consistency, although this is |
| 34 | kind of limited--see the node Concurrency in cvs.texinfo. |
| 35 | |
| 36 | * Readlocks ensure that the RCS file does not change between |
| 37 | RCS_parse and RCS_reparsercsfile time. This one strikes me as |
| 38 | important, although I haven't thought up what bad scenarios might |
| 39 | be. |
| 40 | |
| 41 | * Readlocks ensure that we won't find the file in the state in |
| 42 | which it is in between the calls to add_rcs_file and RCS_checkin in |
| 43 | commit.c (when a file is being added). This state is a state in |
| 44 | which the RCS file parsing routines in rcs.c cannot parse the file. |
| 45 | |
| 46 | * Readlocks ensure that a reader won't try to look at a |
| 47 | half-written fileattr file (fileattr is not updated atomically). |
| 48 | |
| 49 | (see also the description of anonymous read-only access in |
| 50 | "Password authentication security" node in doc/cvs.texinfo). |
| 51 | |
| 52 | While I'm here, I'll try to summarize a few random suggestions |
| 53 | which periodically get made about how locks might be different: |
| 54 | |
| 55 | 1. Check for EROFS. Maybe useful, although in the presence of NFS |
| 56 | EROFS does *not* mean that the file system is unchanging. |
| 57 | |
| 58 | 2. Provide a means to put the cvs locks in some directory apart from |
| 59 | the repository (CVSROOT/locks; a -l option in modules; etc.). |
| 60 | |
| 61 | 3. Provide an option to disable locks for operations which only |
| 62 | read (see above for some of the consequences). |
| 63 | |
| 64 | 4. Have a server internally do the locking. Probably a good |
| 65 | long-term solution, and many people have been working hard on code |
| 66 | changes which would eventually make it possible to have a server |
| 67 | which can handle various connections in one process, but there is |
| 68 | much, much work still to be done before this is feasible. |
| 69 | |
| 70 | 5. Like #4 but use shared memory or something so that the servers |
| 71 | merely need to all be on the same machine. This is a much smaller |
| 72 | change to CVS (it functions much like #2; shared memory might be an |
| 73 | unneeded complication although it presumably would be faster). */ |
| 74 | |
| 75 | #include "cvs.h" |
| 76 | #include <assert.h> |
| 77 | |
| 78 | struct lock { |
| 79 | /* This is the directory in which we may have a lock named by the |
| 80 | readlock variable, a lock named by the writelock variable, and/or |
| 81 | a lock named CVSLCK. The storage is not allocated along with the |
| 82 | struct lock; it is allocated by the Reader_Lock caller or in the |
| 83 | case of writelocks, it is just a pointer to the storage allocated |
| 84 | for the ->key field. */ |
| 85 | char *repository; |
| 86 | /* Do we have a lock named CVSLCK? */ |
| 87 | int have_lckdir; |
| 88 | /* Note there is no way of knowing whether the readlock and writelock |
| 89 | exist. The code which sets the locks doesn't use SIG_beginCrSect |
| 90 | to set a flag like we do for CVSLCK. */ |
| 91 | }; |
| 92 | |
| 93 | static void remove_locks PROTO((void))(void); |
| 94 | static int readers_exist PROTO((char *repository))(char *repository); |
| 95 | static int set_lock PROTO ((struct lock *lock, int will_wait))(struct lock *lock, int will_wait); |
| 96 | static void clear_lock PROTO ((struct lock *lock))(struct lock *lock); |
| 97 | static void set_lockers_name PROTO((struct stat *statp))(struct stat *statp); |
| 98 | static int set_writelock_proc PROTO((Node * p, void *closure))(Node * p, void *closure); |
| 99 | static int unlock_proc PROTO((Node * p, void *closure))(Node * p, void *closure); |
| 100 | static int write_lock PROTO ((struct lock *lock))(struct lock *lock); |
| 101 | static void lock_simple_remove PROTO ((struct lock *lock))(struct lock *lock); |
| 102 | static void lock_wait PROTO((char *repository))(char *repository); |
| 103 | static void lock_obtained PROTO((char *repository))(char *repository); |
| 104 | |
| 105 | /* Malloc'd array containing the username of the whoever has the lock. |
| 106 | Will always be non-NULL in the cases where it is needed. */ |
| 107 | static char *lockers_name; |
| 108 | /* Malloc'd array specifying name of a readlock within a directory. |
| 109 | Or NULL if none. */ |
| 110 | static char *readlock; |
| 111 | /* Malloc'd array specifying name of a writelock within a directory. |
| 112 | Or NULL if none. */ |
| 113 | static char *writelock; |
| 114 | /* Malloc'd array specifying the name of a CVSLCK file (absolute pathname). |
| 115 | Will always be non-NULL in the cases where it is used. */ |
| 116 | static char *masterlock; |
| 117 | static List *locklist; |
| 118 | |
| 119 | #define L_OK0 0 /* success */ |
| 120 | #define L_ERROR1 1 /* error condition */ |
| 121 | #define L_LOCKED2 2 /* lock owned by someone else */ |
| 122 | |
| 123 | /* This is the (single) readlock which is set by Reader_Lock. The |
| 124 | repository field is NULL if there is no such lock. */ |
| 125 | static struct lock global_readlock; |
| 126 | |
| 127 | /* List of locks set by lock_tree_for_write. This is redundant |
| 128 | with locklist, sort of. */ |
| 129 | static List *lock_tree_list; |
| 130 | |
| 131 | /* If we set locks with lock_dir_for_write, then locked_dir contains |
| 132 | the malloc'd name of the repository directory which we have locked. |
| 133 | locked_list is the same thing packaged into a list and is redundant |
| 134 | with locklist the same way that lock_tree_list is. */ |
| 135 | static char *locked_dir; |
| 136 | static List *locked_list; |
| 137 | |
| 138 | /* LockDir from CVSROOT/config. */ |
| 139 | char *lock_dir; |
| 140 | |
| 141 | static char *lock_name PROTO ((char *repository, char *name))(char *repository, char *name); |
| 142 | |
| 143 | /* Return a newly malloc'd string containing the name of the lock for the |
| 144 | repository REPOSITORY and the lock file name within that directory |
| 145 | NAME. Also create the directories in which to put the lock file |
| 146 | if needed (if we need to, could save system call(s) by doing |
| 147 | that only if the actual operation fails. But for now we'll keep |
| 148 | things simple). */ |
| 149 | static char * |
| 150 | lock_name (repository, name) |
| 151 | char *repository; |
| 152 | char *name; |
| 153 | { |
| 154 | char *retval; |
| 155 | char *p; |
| 156 | char *q; |
| 157 | char *short_repos; |
| 158 | mode_t save_umask; |
| 159 | int saved_umask = 0; |
| 160 | |
| 161 | if (lock_dir == NULL((void*)0)) |
| 162 | { |
| 163 | /* This is the easy case. Because the lock files go directly |
| 164 | in the repository, no need to create directories or anything. */ |
| 165 | retval = xmalloc (strlen (repository) + strlen (name) + 10); |
| 166 | (void) sprintf (retval, "%s/%s", repository, name); |
| 167 | } |
| 168 | else |
| 169 | { |
| 170 | struct stat sb; |
| 171 | mode_t new_mode = 0; |
| 172 | |
| 173 | /* The interesting part of the repository is the part relative |
| 174 | to CVSROOT. */ |
| 175 | assert (current_parsed_root != NULL)((current_parsed_root != ((void*)0)) ? (void)0 : __assert2("/usr/src/gnu/usr.bin/cvs/src/lock.c" , 175, __func__, "current_parsed_root != NULL")); |
| 176 | assert (current_parsed_root->directory != NULL)((current_parsed_root->directory != ((void*)0)) ? (void)0 : __assert2("/usr/src/gnu/usr.bin/cvs/src/lock.c", 176, __func__ , "current_parsed_root->directory != NULL")); |
| 177 | assert (strncmp (repository, current_parsed_root->directory,((strncmp (repository, current_parsed_root->directory, strlen (current_parsed_root->directory)) == 0) ? (void)0 : __assert2 ("/usr/src/gnu/usr.bin/cvs/src/lock.c", 178, __func__, "strncmp (repository, current_parsed_root->directory, strlen (current_parsed_root->directory)) == 0" )) |
| 178 | strlen (current_parsed_root->directory)) == 0)((strncmp (repository, current_parsed_root->directory, strlen (current_parsed_root->directory)) == 0) ? (void)0 : __assert2 ("/usr/src/gnu/usr.bin/cvs/src/lock.c", 178, __func__, "strncmp (repository, current_parsed_root->directory, strlen (current_parsed_root->directory)) == 0" )); |
| 179 | short_repos = repository + strlen (current_parsed_root->directory) + 1; |
| 180 | |
| 181 | if (strcmp (repository, current_parsed_root->directory) == 0) |
| 182 | short_repos = "."; |
| 183 | else |
| 184 | assert (short_repos[-1] == '/')((short_repos[-1] == '/') ? (void)0 : __assert2("/usr/src/gnu/usr.bin/cvs/src/lock.c" , 184, __func__, "short_repos[-1] == '/'")); |
| 185 | |
| 186 | retval = xmalloc (strlen (lock_dir) |
| 187 | + strlen (short_repos) |
| 188 | + strlen (name) |
| 189 | + 10); |
| 190 | strcpy (retval, lock_dir); |
| 191 | q = retval + strlen (retval); |
| 192 | *q++ = '/'; |
| 193 | |
| 194 | strcpy (q, short_repos); |
| 195 | |
| 196 | /* In the common case, where the directory already exists, let's |
| 197 | keep it to one system call. */ |
| 198 | if (CVS_STATstat (retval, &sb) < 0) |
| 199 | { |
| 200 | /* If we need to be creating more than one directory, we'll |
| 201 | get the existence_error here. */ |
| 202 | if (!existence_error (errno)(((*__errno())) == 2)) |
| 203 | error (1, errno(*__errno()), "cannot stat directory %s", retval); |
| 204 | } |
| 205 | else |
| 206 | { |
| 207 | if (S_ISDIR (sb.st_mode)((sb.st_mode & 0170000) == 0040000)) |
| 208 | goto created; |
| 209 | else |
| 210 | error (1, 0, "%s is not a directory", retval); |
| 211 | } |
| 212 | |
| 213 | /* Now add the directories one at a time, so we can create |
| 214 | them if needed. |
| 215 | |
| 216 | The idea behind the new_mode stuff is that the directory we |
| 217 | end up creating will inherit permissions from its parent |
| 218 | directory (we re-set new_mode with each EEXIST). CVSUMASK |
| 219 | isn't right, because typically the reason for LockDir is to |
| 220 | use a different set of permissions. We probably want to |
| 221 | inherit group ownership also (but we don't try to deal with |
| 222 | that, some systems do it for us either always or when g+s is on). |
| 223 | |
| 224 | We don't try to do anything about the permissions on the lock |
| 225 | files themselves. The permissions don't really matter so much |
| 226 | because the locks will generally be removed by the process |
| 227 | which created them. */ |
| 228 | |
| 229 | if (CVS_STATstat (lock_dir, &sb) < 0) |
| 230 | error (1, errno(*__errno()), "cannot stat %s", lock_dir); |
| 231 | new_mode = sb.st_mode; |
| 232 | save_umask = umask (0000); |
| 233 | saved_umask = 1; |
| 234 | |
| 235 | p = short_repos; |
| 236 | while (1) |
| 237 | { |
| 238 | while (!ISDIRSEP (*p)((*p) == '/') && *p != '\0') |
| 239 | ++p; |
| 240 | if (ISDIRSEP (*p)((*p) == '/')) |
| 241 | { |
| 242 | strncpy (q, short_repos, p - short_repos); |
| 243 | q[p - short_repos] = '\0'; |
| 244 | if (!ISDIRSEP (q[p - short_repos - 1])((q[p - short_repos - 1]) == '/') |
| 245 | && CVS_MKDIRmkdir (retval, new_mode) < 0) |
| 246 | { |
| 247 | int saved_errno = errno(*__errno()); |
| 248 | if (saved_errno != EEXIST17) |
| 249 | error (1, errno(*__errno()), "cannot make directory %s", retval); |
| 250 | else |
| 251 | { |
| 252 | if (CVS_STATstat (retval, &sb) < 0) |
| 253 | error (1, errno(*__errno()), "cannot stat %s", retval); |
| 254 | new_mode = sb.st_mode; |
| 255 | } |
| 256 | } |
| 257 | ++p; |
| 258 | } |
| 259 | else |
| 260 | { |
| 261 | strcpy (q, short_repos); |
| 262 | if (CVS_MKDIRmkdir (retval, new_mode) < 0 |
| 263 | && errno(*__errno()) != EEXIST17) |
| 264 | error (1, errno(*__errno()), "cannot make directory %s", retval); |
| 265 | goto created; |
| 266 | } |
| 267 | } |
| 268 | created:; |
| 269 | |
| 270 | strcat (retval, "/"); |
| 271 | strcat (retval, name); |
| 272 | |
| 273 | if (saved_umask) |
| 274 | { |
| 275 | assert (umask (save_umask) == 0000)((umask (save_umask) == 0000) ? (void)0 : __assert2("/usr/src/gnu/usr.bin/cvs/src/lock.c" , 275, __func__, "umask (save_umask) == 0000")); |
| 276 | saved_umask = 0; |
| 277 | } |
| 278 | } |
| 279 | return retval; |
| 280 | } |
| 281 | |
| 282 | /* |
| 283 | * Clean up all outstanding locks |
| 284 | */ |
| 285 | void |
| 286 | Lock_Cleanup () |
| 287 | { |
| 288 | /* FIXME: error handling here is kind of bogus; we sometimes will call |
| 289 | error, which in turn can call us again. For the moment work around |
| 290 | this by refusing to reenter this function (this is a kludge). */ |
| 291 | /* FIXME-reentrancy: the workaround isn't reentrant. */ |
| 292 | static int in_lock_cleanup = 0; |
| 293 | |
| 294 | if (in_lock_cleanup) |
| 295 | return; |
| 296 | in_lock_cleanup = 1; |
| 297 | |
| 298 | remove_locks (); |
| 299 | |
| 300 | dellist (&lock_tree_list); |
| 301 | |
| 302 | if (locked_dir != NULL((void*)0)) |
| 303 | { |
| 304 | dellist (&locked_list); |
| 305 | free (locked_dir); |
| 306 | locked_dir = NULL((void*)0); |
| 307 | locked_list = NULL((void*)0); |
| 308 | } |
| 309 | in_lock_cleanup = 0; |
| 310 | } |
| 311 | |
| 312 | /* |
| 313 | * Remove locks without discarding the lock information |
| 314 | */ |
| 315 | static void |
| 316 | remove_locks () |
| 317 | { |
| 318 | /* clean up simple locks (if any) */ |
| 319 | if (global_readlock.repository != NULL((void*)0)) |
| 320 | { |
| 321 | lock_simple_remove (&global_readlock); |
| 322 | global_readlock.repository = NULL((void*)0); |
| 323 | } |
| 324 | |
| 325 | /* clean up multiple locks (if any) */ |
| 326 | if (locklist != (List *) NULL((void*)0)) |
| 327 | { |
| 328 | (void) walklist (locklist, unlock_proc, NULL((void*)0)); |
| 329 | locklist = (List *) NULL((void*)0); |
| 330 | } |
| 331 | } |
| 332 | |
| 333 | /* |
| 334 | * walklist proc for removing a list of locks |
| 335 | */ |
| 336 | static int |
| 337 | unlock_proc (p, closure) |
| 338 | Node *p; |
| 339 | void *closure; |
| 340 | { |
| 341 | lock_simple_remove ((struct lock *)p->data); |
| 342 | return (0); |
| 343 | } |
| 344 | |
| 345 | /* Remove the lock files. */ |
| 346 | static void |
| 347 | lock_simple_remove (lock) |
| 348 | struct lock *lock; |
| 349 | { |
| 350 | char *tmp; |
| 351 | |
| 352 | /* If readlock is set, the lock directory *might* have been created, but |
| 353 | since Reader_Lock doesn't use SIG_beginCrSect the way that set_lock |
| 354 | does, we don't know that. That is why we need to check for |
| 355 | existence_error here. */ |
| 356 | if (readlock != NULL((void*)0)) |
| 357 | { |
| 358 | tmp = lock_name (lock->repository, readlock); |
| 359 | if ( CVS_UNLINKunlink (tmp) < 0 && ! existence_error (errno)(((*__errno())) == 2)) |
| 360 | error (0, errno(*__errno()), "failed to remove lock %s", tmp); |
| 361 | free (tmp); |
| 362 | } |
| 363 | |
| 364 | /* If writelock is set, the lock directory *might* have been created, but |
| 365 | since write_lock doesn't use SIG_beginCrSect the way that set_lock |
| 366 | does, we don't know that. That is why we need to check for |
| 367 | existence_error here. */ |
| 368 | if (writelock != NULL((void*)0)) |
| 369 | { |
| 370 | tmp = lock_name (lock->repository, writelock); |
| 371 | if ( CVS_UNLINKunlink (tmp) < 0 && ! existence_error (errno)(((*__errno())) == 2)) |
| 372 | error (0, errno(*__errno()), "failed to remove lock %s", tmp); |
| 373 | free (tmp); |
| 374 | } |
| 375 | |
| 376 | if (lock->have_lckdir) |
| 377 | { |
| 378 | tmp = lock_name (lock->repository, CVSLCK"#cvs.lock"); |
| 379 | SIG_beginCrSect (); |
| 380 | if (CVS_RMDIRrmdir (tmp) < 0) |
| 381 | error (0, errno(*__errno()), "failed to remove lock dir %s", tmp); |
| 382 | lock->have_lckdir = 0; |
| 383 | SIG_endCrSect (); |
| 384 | free (tmp); |
| 385 | } |
| 386 | } |
| 387 | |
| 388 | /* |
| 389 | * Create a lock file for readers |
| 390 | */ |
| 391 | int |
| 392 | Reader_Lock (xrepository) |
| 393 | char *xrepository; |
| 394 | { |
| 395 | int err = 0; |
| 396 | FILE *fp; |
| 397 | char *tmp; |
| 398 | |
| 399 | if (noexec || readonlyfs) |
| 400 | return (0); |
| 401 | |
| 402 | /* we only do one directory at a time for read locks! */ |
| 403 | if (global_readlock.repository != NULL((void*)0)) |
| 404 | { |
| 405 | error (0, 0, "Reader_Lock called while read locks set - Help!"); |
| 406 | return (1); |
| 407 | } |
| 408 | |
| 409 | if (readlock == NULL((void*)0)) |
| 410 | { |
| 411 | readlock = xmalloc (strlen (hostname) + sizeof (CVSRFL"#cvs.rfl") + 40); |
| 412 | (void) sprintf (readlock, |
| 413 | #ifdef HAVE_LONG_FILE_NAMES1 |
| 414 | "%s.%s.%ld", CVSRFL"#cvs.rfl", hostname, |
| 415 | #else |
| 416 | "%s.%ld", CVSRFL"#cvs.rfl", |
| 417 | #endif |
| 418 | (long) getpid ()); |
| 419 | } |
| 420 | |
| 421 | /* remember what we're locking (for Lock_Cleanup) */ |
| 422 | global_readlock.repository = xrepository; |
| 423 | |
| 424 | /* get the lock dir for our own */ |
| 425 | if (set_lock (&global_readlock, 1) != L_OK0) |
| 426 | { |
| 427 | error (0, 0, "failed to obtain dir lock in repository `%s'", |
| 428 | xrepository); |
| 429 | if (readlock != NULL((void*)0)) |
| 430 | free (readlock); |
| 431 | readlock = NULL((void*)0); |
| 432 | /* We don't set global_readlock.repository to NULL. I think this |
| 433 | only works because recurse.c will give a fatal error if we return |
| 434 | a nonzero value. */ |
| 435 | return (1); |
| 436 | } |
| 437 | |
| 438 | /* write a read-lock */ |
| 439 | tmp = lock_name (xrepository, readlock); |
| 440 | if ((fp = CVS_FOPENfopen (tmp, "w+")) == NULL((void*)0) || fclose (fp) == EOF(-1)) |
| 441 | { |
| 442 | error (0, errno(*__errno()), "cannot create read lock in repository `%s'", |
| 443 | xrepository); |
| 444 | if (readlock != NULL((void*)0)) |
| 445 | free (readlock); |
| 446 | readlock = NULL((void*)0); |
| 447 | err = 1; |
| 448 | } |
| 449 | free (tmp); |
| 450 | |
| 451 | /* free the lock dir */ |
| 452 | clear_lock (&global_readlock); |
| 453 | |
| 454 | return (err); |
| 455 | } |
| 456 | |
| 457 | /* |
| 458 | * Lock a list of directories for writing |
| 459 | */ |
| 460 | static char *lock_error_repos; |
| 461 | static int lock_error; |
| 462 | |
| 463 | static int Writer_Lock PROTO ((List * list))(List * list); |
| 464 | |
| 465 | static int |
| 466 | Writer_Lock (list) |
| 467 | List *list; |
| 468 | { |
| 469 | char *wait_repos; |
| 470 | |
| 471 | if (noexec) |
| 472 | return (0); |
| 473 | |
| 474 | /* We only know how to do one list at a time */ |
| 475 | if (locklist != (List *) NULL((void*)0)) |
| 476 | { |
| 477 | error (0, 0, "Writer_Lock called while write locks set - Help!"); |
| 478 | return (1); |
| 479 | } |
| 480 | |
| 481 | wait_repos = NULL((void*)0); |
| 482 | for (;;) |
| 483 | { |
| 484 | /* try to lock everything on the list */ |
| 485 | lock_error = L_OK0; /* init for set_writelock_proc */ |
| 486 | lock_error_repos = (char *) NULL((void*)0); /* init for set_writelock_proc */ |
| 487 | locklist = list; /* init for Lock_Cleanup */ |
| 488 | if (lockers_name != NULL((void*)0)) |
| 489 | free (lockers_name); |
| 490 | lockers_name = xstrdup ("unknown"); |
| 491 | |
| 492 | (void) walklist (list, set_writelock_proc, NULL((void*)0)); |
| 493 | |
| 494 | switch (lock_error) |
| 495 | { |
| 496 | case L_ERROR1: /* Real Error */ |
| 497 | if (wait_repos != NULL((void*)0)) |
| 498 | free (wait_repos); |
| 499 | Lock_Cleanup (); /* clean up any locks we set */ |
| 500 | error (0, 0, "lock failed - giving up"); |
| 501 | return (1); |
| 502 | |
| 503 | case L_LOCKED2: /* Someone already had a lock */ |
| 504 | remove_locks (); /* clean up any locks we set */ |
| 505 | lock_wait (lock_error_repos); /* sleep a while and try again */ |
| 506 | wait_repos = xstrdup (lock_error_repos); |
| 507 | continue; |
| 508 | |
| 509 | case L_OK0: /* we got the locks set */ |
| 510 | if (wait_repos != NULL((void*)0)) |
| 511 | { |
| 512 | lock_obtained (wait_repos); |
| 513 | free (wait_repos); |
| 514 | } |
| 515 | return (0); |
| 516 | |
| 517 | default: |
| 518 | if (wait_repos != NULL((void*)0)) |
| 519 | free (wait_repos); |
| 520 | error (0, 0, "unknown lock status %d in Writer_Lock", |
| 521 | lock_error); |
| 522 | return (1); |
| 523 | } |
| 524 | } |
| 525 | } |
| 526 | |
| 527 | /* |
| 528 | * walklist proc for setting write locks |
| 529 | */ |
| 530 | static int |
| 531 | set_writelock_proc (p, closure) |
| 532 | Node *p; |
| 533 | void *closure; |
| 534 | { |
| 535 | /* if some lock was not OK, just skip this one */ |
| 536 | if (lock_error != L_OK0) |
| 537 | return (0); |
| 538 | |
| 539 | /* apply the write lock */ |
| 540 | lock_error_repos = p->key; |
| 541 | lock_error = write_lock ((struct lock *)p->data); |
| 542 | return (0); |
| 543 | } |
| 544 | |
| 545 | /* |
| 546 | * Create a lock file for writers returns L_OK if lock set ok, L_LOCKED if |
| 547 | * lock held by someone else or L_ERROR if an error occurred |
| 548 | */ |
| 549 | static int |
| 550 | write_lock (lock) |
| 551 | struct lock *lock; |
| 552 | { |
| 553 | int status; |
| 554 | FILE *fp; |
| 555 | char *tmp; |
| 556 | |
| 557 | if (writelock == NULL((void*)0)) |
| 558 | { |
| 559 | writelock = xmalloc (strlen (hostname) + sizeof (CVSWFL"#cvs.wfl") + 40); |
| 560 | (void) sprintf (writelock, |
| 561 | #ifdef HAVE_LONG_FILE_NAMES1 |
| 562 | "%s.%s.%ld", CVSWFL"#cvs.wfl", hostname, |
| 563 | #else |
| 564 | "%s.%ld", CVSWFL"#cvs.wfl", |
| 565 | #endif |
| 566 | (long) getpid()); |
| 567 | } |
| 568 | |
| 569 | /* make sure the lock dir is ours (not necessarily unique to us!) */ |
| 570 | status = set_lock (lock, 0); |
| 571 | if (status == L_OK0) |
| 572 | { |
| 573 | /* we now own a writer - make sure there are no readers */ |
| 574 | if (readers_exist (lock->repository)) |
| 575 | { |
| 576 | /* clean up the lock dir if we created it */ |
| 577 | if (status == L_OK0) |
| 578 | { |
| 579 | clear_lock (lock); |
| 580 | } |
| 581 | |
| 582 | /* indicate we failed due to read locks instead of error */ |
| 583 | return (L_LOCKED2); |
| 584 | } |
| 585 | |
| 586 | /* write the write-lock file */ |
| 587 | tmp = lock_name (lock->repository, writelock); |
| 588 | if ((fp = CVS_FOPENfopen (tmp, "w+")) == NULL((void*)0) || fclose (fp) == EOF(-1)) |
| 589 | { |
| 590 | int xerrno = errno(*__errno()); |
| 591 | |
| 592 | if ( CVS_UNLINKunlink (tmp) < 0 && ! existence_error (errno)(((*__errno())) == 2)) |
| 593 | error (0, errno(*__errno()), "failed to remove lock %s", tmp); |
| 594 | |
| 595 | /* free the lock dir if we created it */ |
| 596 | if (status == L_OK0) |
| 597 | { |
| 598 | clear_lock (lock); |
| 599 | } |
| 600 | |
| 601 | /* return the error */ |
| 602 | error (0, xerrno, "cannot create write lock in repository `%s'", |
| 603 | lock->repository); |
| 604 | free (tmp); |
| 605 | return (L_ERROR1); |
| 606 | } |
| 607 | free (tmp); |
| 608 | return (L_OK0); |
| 609 | } |
| 610 | else |
| 611 | return (status); |
| 612 | } |
| 613 | |
| 614 | /* |
| 615 | * readers_exist() returns 0 if there are no reader lock files remaining in |
| 616 | * the repository; else 1 is returned, to indicate that the caller should |
| 617 | * sleep a while and try again. |
| 618 | */ |
| 619 | static int |
| 620 | readers_exist (repository) |
| 621 | char *repository; |
| 622 | { |
| 623 | char *line; |
| 624 | DIR *dirp; |
| 625 | struct dirent *dp; |
| 626 | struct stat sb; |
| 627 | int ret = 0; |
| 628 | |
| 629 | #ifdef CVS_FUDGELOCKS |
| 630 | again: |
| 631 | #endif |
| 632 | |
| 633 | if ((dirp = CVS_OPENDIRopendir (repository)) == NULL((void*)0)) |
| 634 | error (1, 0, "cannot open directory %s", repository); |
| 635 | |
| 636 | errno(*__errno()) = 0; |
| 637 | while ((dp = CVS_READDIRreaddir (dirp)) != NULL((void*)0)) |
| 638 | { |
| 639 | if (CVS_FNMATCHfnmatch (CVSRFLPAT"#cvs.rfl.*", dp->d_name, 0) == 0) |
| 640 | { |
| 641 | #ifdef CVS_FUDGELOCKS |
| 642 | time_t now; |
| 643 | (void) time (&now); |
| 644 | #endif |
| 645 | |
| 646 | line = xmalloc (strlen (repository) + strlen (dp->d_name) + 5); |
| 647 | (void) sprintf (line, "%s/%s", repository, dp->d_name); |
| 648 | if ( CVS_STATstat (line, &sb) != -1) |
| 649 | { |
| 650 | #ifdef CVS_FUDGELOCKS |
| 651 | /* |
| 652 | * If the create time of the file is more than CVSLCKAGE |
| 653 | * seconds ago, try to clean-up the lock file, and if |
| 654 | * successful, re-open the directory and try again. |
| 655 | */ |
| 656 | if (now >= (sb.st_ctimest_ctim.tv_sec + CVSLCKAGE(60*60)) && CVS_UNLINKunlink (line) != -1) |
| 657 | { |
| 658 | (void) CVS_CLOSEDIRclosedir (dirp); |
| 659 | free (line); |
| 660 | goto again; |
| 661 | } |
| 662 | #endif |
| 663 | set_lockers_name (&sb); |
| 664 | } |
| 665 | else |
| 666 | { |
| 667 | /* If the file doesn't exist, it just means that it disappeared |
| 668 | between the time we did the readdir and the time we did |
| 669 | the stat. */ |
| 670 | if (!existence_error (errno)(((*__errno())) == 2)) |
| 671 | error (0, errno(*__errno()), "cannot stat %s", line); |
| 672 | } |
| 673 | errno(*__errno()) = 0; |
| 674 | free (line); |
| 675 | |
| 676 | ret = 1; |
| 677 | break; |
| 678 | } |
| 679 | errno(*__errno()) = 0; |
| 680 | } |
| 681 | if (errno(*__errno()) != 0) |
| 682 | error (0, errno(*__errno()), "error reading directory %s", repository); |
| 683 | |
| 684 | CVS_CLOSEDIRclosedir (dirp); |
| 685 | return (ret); |
| 686 | } |
| 687 | |
| 688 | /* |
| 689 | * Set the static variable lockers_name appropriately, based on the stat |
| 690 | * structure passed in. |
| 691 | */ |
| 692 | static void |
| 693 | set_lockers_name (statp) |
| 694 | struct stat *statp; |
| 695 | { |
| 696 | struct passwd *pw; |
| 697 | |
| 698 | if (lockers_name != NULL((void*)0)) |
| 699 | free (lockers_name); |
| 700 | if ((pw = (struct passwd *) getpwuid (statp->st_uid)) != |
| 701 | (struct passwd *) NULL((void*)0)) |
| 702 | { |
| 703 | lockers_name = xstrdup (pw->pw_name); |
| 704 | } |
| 705 | else |
| 706 | { |
| 707 | lockers_name = xmalloc (20); |
| 708 | (void) sprintf (lockers_name, "uid%lu", (unsigned long) statp->st_uid); |
| 709 | } |
| 710 | } |
| 711 | |
| 712 | /* |
| 713 | * Persistently tries to make the directory "lckdir",, which serves as a |
| 714 | * lock. If the create time on the directory is greater than CVSLCKAGE |
| 715 | * seconds old, just try to remove the directory. |
| 716 | */ |
| 717 | static int |
| 718 | set_lock (lock, will_wait) |
| 719 | struct lock *lock; |
| 720 | int will_wait; |
| 721 | { |
| 722 | int waited; |
| 723 | struct stat sb; |
| 724 | mode_t omask; |
| 725 | #ifdef CVS_FUDGELOCKS |
| 726 | time_t now; |
| 727 | #endif |
| 728 | |
| 729 | if (masterlock != NULL((void*)0)) |
| 730 | free (masterlock); |
| 731 | masterlock = lock_name (lock->repository, CVSLCK"#cvs.lock"); |
| 732 | |
| 733 | /* |
| 734 | * Note that it is up to the callers of set_lock() to arrange for signal |
| 735 | * handlers that do the appropriate things, like remove the lock |
| 736 | * directory before they exit. |
| 737 | */ |
| 738 | waited = 0; |
| 739 | lock->have_lckdir = 0; |
| 740 | for (;;) |
| 741 | { |
| 742 | int status = -1; |
| 743 | omask = umask (cvsumask); |
| 744 | SIG_beginCrSect (); |
| 745 | if (CVS_MKDIRmkdir (masterlock, 0777) == 0) |
| 746 | { |
| 747 | lock->have_lckdir = 1; |
| 748 | SIG_endCrSect (); |
| 749 | status = L_OK0; |
| 750 | if (waited) |
| 751 | lock_obtained (lock->repository); |
| 752 | goto out; |
| 753 | } |
| 754 | SIG_endCrSect (); |
| 755 | out: |
| 756 | (void) umask (omask); |
| 757 | if (status != -1) |
| 758 | return status; |
| 759 | |
| 760 | if (errno(*__errno()) != EEXIST17) |
| 761 | { |
| 762 | error (0, errno(*__errno()), |
| 763 | "failed to create lock directory for `%s' (%s)", |
| 764 | lock->repository, masterlock); |
| 765 | return (L_ERROR1); |
| 766 | } |
| 767 | |
| 768 | /* Find out who owns the lock. If the lock directory is |
| 769 | non-existent, re-try the loop since someone probably just |
| 770 | removed it (thus releasing the lock). */ |
| 771 | if (CVS_STATstat (masterlock, &sb) < 0) |
| 772 | { |
| 773 | if (existence_error (errno)(((*__errno())) == 2)) |
| 774 | continue; |
| 775 | |
| 776 | error (0, errno(*__errno()), "couldn't stat lock directory `%s'", masterlock); |
| 777 | return (L_ERROR1); |
| 778 | } |
| 779 | |
| 780 | #ifdef CVS_FUDGELOCKS |
| 781 | /* |
| 782 | * If the create time of the directory is more than CVSLCKAGE seconds |
| 783 | * ago, try to clean-up the lock directory, and if successful, just |
| 784 | * quietly retry to make it. |
| 785 | */ |
| 786 | (void) time (&now); |
| 787 | if (now >= (sb.st_ctimest_ctim.tv_sec + CVSLCKAGE(60*60))) |
| 788 | { |
| 789 | if (CVS_RMDIRrmdir (masterlock) >= 0) |
| 790 | continue; |
| 791 | } |
| 792 | #endif |
| 793 | |
| 794 | /* set the lockers name */ |
| 795 | set_lockers_name (&sb); |
| 796 | |
| 797 | /* if he wasn't willing to wait, return an error */ |
| 798 | if (!will_wait) |
| 799 | return (L_LOCKED2); |
| 800 | lock_wait (lock->repository); |
| 801 | waited = 1; |
| 802 | } |
| 803 | } |
| 804 | |
| 805 | /* |
| 806 | * Clear master lock. We don't have to recompute the lock name since |
| 807 | * clear_lock is never called except after a successful set_lock(). |
| 808 | */ |
| 809 | static void |
| 810 | clear_lock (lock) |
| 811 | struct lock *lock; |
| 812 | { |
| 813 | SIG_beginCrSect (); |
| 814 | if (CVS_RMDIRrmdir (masterlock) < 0) |
| 815 | error (0, errno(*__errno()), "failed to remove lock dir `%s'", masterlock); |
| 816 | lock->have_lckdir = 0; |
| 817 | SIG_endCrSect (); |
| 818 | } |
| 819 | |
| 820 | /* |
| 821 | * Print out a message that the lock is still held, then sleep a while. |
| 822 | */ |
| 823 | static void |
| 824 | lock_wait (repos) |
| 825 | char *repos; |
| 826 | { |
| 827 | time_t now; |
| 828 | char *msg; |
| 829 | |
| 830 | (void) time (&now); |
| 831 | msg = xmalloc (100 + strlen (lockers_name) + strlen (repos)); |
| 832 | sprintf (msg, "[%8.8s] waiting for %s's lock in %s", ctime (&now) + 11, |
| 833 | lockers_name, repos); |
| 834 | error (0, 0, "%s", msg); |
| 835 | /* Call cvs_flusherr to ensure that the user sees this message as |
| 836 | soon as possible. */ |
| 837 | cvs_flusherr (); |
| 838 | free (msg); |
| 839 | (void) sleep (CVSLCKSLEEP30); |
| 840 | } |
| 841 | |
| 842 | /* |
| 843 | * Print out a message when we obtain a lock. |
| 844 | */ |
| 845 | static void |
| 846 | lock_obtained (repos) |
| 847 | char *repos; |
| 848 | { |
| 849 | time_t now; |
| 850 | char *msg; |
| 851 | |
| 852 | (void) time (&now); |
| 853 | msg = xmalloc (100 + strlen (repos)); |
| 854 | sprintf (msg, "[%8.8s] obtained lock in %s", ctime (&now) + 11, repos); |
| 855 | error (0, 0, "%s", msg); |
| 856 | /* Call cvs_flusherr to ensure that the user sees this message as |
| 857 | soon as possible. */ |
| 858 | cvs_flusherr (); |
| 859 | free (msg); |
| 860 | } |
| 861 | |
| 862 | static int lock_filesdoneproc PROTO ((void *callerdat, int err,(void *callerdat, int err, char *repository, char *update_dir , List *entries) |
| 863 | char *repository, char *update_dir,(void *callerdat, int err, char *repository, char *update_dir , List *entries) |
| 864 | List *entries))(void *callerdat, int err, char *repository, char *update_dir , List *entries); |
| 865 | |
| 866 | /* |
| 867 | * Create a list of repositories to lock |
| 868 | */ |
| 869 | /* ARGSUSED */ |
| 870 | static int |
| 871 | lock_filesdoneproc (callerdat, err, repository, update_dir, entries) |
| 872 | void *callerdat; |
| 873 | int err; |
| 874 | char *repository; |
| 875 | char *update_dir; |
| 876 | List *entries; |
| 877 | { |
| 878 | Node *p; |
| 879 | |
| 880 | p = getnode (); |
| 881 | p->type = LOCK; |
| 882 | p->key = xstrdup (repository); |
| 883 | p->data = xmalloc (sizeof (struct lock)); |
| 884 | ((struct lock *)p->data)->repository = p->key; |
| 885 | ((struct lock *)p->data)->have_lckdir = 0; |
| 886 | |
| 887 | /* FIXME-KRP: this error condition should not simply be passed by. */ |
| 888 | if (p->key == NULL((void*)0) || addnode (lock_tree_list, p) != 0) |
| 889 | freenode (p); |
| 890 | return (err); |
| 891 | } |
| 892 | |
| 893 | void |
| 894 | lock_tree_for_write (argc, argv, local, which, aflag) |
| 895 | int argc; |
| 896 | char **argv; |
| 897 | int local; |
| 898 | int which; |
| 899 | int aflag; |
| 900 | { |
| 901 | int err; |
| 902 | /* |
| 903 | * Run the recursion processor to find all the dirs to lock and lock all |
| 904 | * the dirs |
| 905 | */ |
| 906 | lock_tree_list = getlist (); |
| 907 | err = start_recursion ((FILEPROC) NULL((void*)0), lock_filesdoneproc, |
Value stored to 'err' is never read | |
| 908 | (DIRENTPROC) NULL((void*)0), (DIRLEAVEPROC) NULL((void*)0), NULL((void*)0), argc, |
| 909 | argv, local, which, aflag, 0, (char *) NULL((void*)0), 0); |
| 910 | sortlist (lock_tree_list, fsortcmp); |
| 911 | if (Writer_Lock (lock_tree_list) != 0) |
| 912 | error (1, 0, "lock failed - giving up"); |
| 913 | } |
| 914 | |
| 915 | /* Lock a single directory in REPOSITORY. It is OK to call this if |
| 916 | a lock has been set with lock_dir_for_write; the new lock will replace |
| 917 | the old one. If REPOSITORY is NULL, don't do anything. */ |
| 918 | void |
| 919 | lock_dir_for_write (repository) |
| 920 | char *repository; |
| 921 | { |
| 922 | if (repository != NULL((void*)0) |
| 923 | && (locked_dir == NULL((void*)0) |
| 924 | || strcmp (locked_dir, repository) != 0)) |
| 925 | { |
| 926 | Node *node; |
| 927 | |
| 928 | if (locked_dir != NULL((void*)0)) |
| 929 | Lock_Cleanup (); |
| 930 | |
| 931 | locked_dir = xstrdup (repository); |
| 932 | locked_list = getlist (); |
| 933 | node = getnode (); |
| 934 | node->type = LOCK; |
| 935 | node->key = xstrdup (repository); |
| 936 | node->data = xmalloc (sizeof (struct lock)); |
| 937 | ((struct lock *)node->data)->repository = node->key; |
| 938 | ((struct lock *)node->data)->have_lckdir = 0; |
| 939 | |
| 940 | (void) addnode (locked_list, node); |
| 941 | Writer_Lock (locked_list); |
| 942 | } |
| 943 | } |