2 * testcode/lock_verify.c - verifier program for lock traces, checks order.
4 * Copyright (c) 2007, NLnet Labs. All rights reserved.
6 * This software is open source.
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9 * modification, are permitted provided that the following conditions
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39 * This file checks the lock traces generated by checklock.c.
40 * Checks if locks are consistently locked in the same order.
41 * If not, this can lead to deadlock if threads execute the different
42 * ordering at the same time.
48 #include "util/rbtree.h"
49 #include "util/locks.h"
50 #include "util/fptr_wlist.h"
52 /* --- data structures --- */
55 /** keep track of lock id in lock-verify application
56 * Also defined in smallapp/worker_cb.c for fptr_wlist encapsulation
57 * breakage (the security tests break encapsulation for this test app) */
59 /** the thread id that created it */
61 /** the instance number of creation */
67 /** rbnode in all tree */
71 /** the creation file */
75 /** set of all locks that are smaller than this one (locked earlier) */
77 /** during depthfirstsearch, this is a linked list of the stack
78 * of locks. points to the next lock bigger than this one. */
79 struct lock_ref* dfs_next;
80 /** if lock has been visited (all smaller locks have been compared to
81 * this lock), only need to compare this with all unvisited(bigger)
86 /** reference to a lock in a rbtree set */
88 /** rbnode, key is an order_id ptr */
90 /** the lock referenced */
91 struct order_lock* lock;
92 /** why is this ref */
98 /** count of errors detected */
99 static int errors_detected = 0;
103 /** print program usage help */
107 printf("lock_verify <trace files>\n");
110 /** read header entry.
111 * @param in: file to read header of.
112 * @return: False if it does not belong to the rest. */
114 read_header(FILE* in)
119 static int have_values = 0;
120 static time_t the_time;
121 static pid_t the_pid;
122 static int threads[256];
124 if(fread(&t, sizeof(t), 1, in) != 1 ||
125 fread(&thrno, sizeof(thrno), 1, in) != 1 ||
126 fread(&p, sizeof(p), 1, in) != 1) {
127 fatal_exit("fread failed");
129 /* check these values are sorta OK */
133 memset(threads, 0, 256*sizeof(int));
135 fatal_exit("Thread number too big. %d", thrno);
139 printf(" trace %d from pid %u on %s", thrno,
140 (unsigned)p, ctime(&t));
143 printf(" has pid %u, not %u. Skipped.\n",
144 (unsigned)p, (unsigned)the_pid);
148 fatal_exit("same threadno in two files");
150 if( abs((int)(the_time - t)) > 3600)
151 fatal_exit("input files from different times: %u %u",
152 (unsigned)the_time, (unsigned)t);
153 printf(" trace of thread %u:%d\n", (unsigned)p, thrno);
158 /** max length of strings: filenames and function names. */
160 /** read a string from file, false on error */
161 static int readup_str(char** str, FILE* in)
167 while( (c = fgetc(in)) != 0) {
169 fatal_exit("eof in readstr, file too short");
172 fatal_exit("string too long, bad file format");
180 /** read creation entry */
181 static void read_create(rbtree_t* all, FILE* in)
183 struct order_lock* o = calloc(1, sizeof(struct order_lock));
184 if(!o) fatal_exit("malloc failure");
185 if(fread(&o->id.thr, sizeof(int), 1, in) != 1 ||
186 fread(&o->id.instance, sizeof(int), 1, in) != 1 ||
187 !readup_str(&o->create_file, in) ||
188 fread(&o->create_line, sizeof(int), 1, in) != 1)
189 fatal_exit("fread failed");
190 o->smaller = rbtree_create(order_lock_cmp);
191 o->node.key = &o->id;
192 if(!rbtree_insert(all, &o->node)) {
193 /* already inserted */
194 struct order_lock* a = (struct order_lock*)rbtree_search(all,
197 a->create_file = o->create_file;
198 a->create_line = o->create_line;
203 if(verb) printf("read create %u %u %s %d\n",
204 (unsigned)o->id.thr, (unsigned)o->id.instance,
205 o->create_file, o->create_line);
208 /** insert lock entry (empty) into list */
209 static struct order_lock*
210 insert_lock(rbtree_t* all, struct order_id* id)
212 struct order_lock* o = calloc(1, sizeof(struct order_lock));
213 if(!o) fatal_exit("malloc failure");
214 o->smaller = rbtree_create(order_lock_cmp);
216 o->node.key = &o->id;
217 if(!rbtree_insert(all, &o->node))
218 fatal_exit("insert fail should not happen");
222 /** read lock entry */
223 static void read_lock(rbtree_t* all, FILE* in, int val)
225 struct order_id prev_id, now_id;
226 struct lock_ref* ref;
227 struct order_lock* prev, *now;
228 ref = (struct lock_ref*)calloc(1, sizeof(struct lock_ref));
229 if(!ref) fatal_exit("malloc failure");
231 if(fread(&prev_id.instance, sizeof(int), 1, in) != 1 ||
232 fread(&now_id.thr, sizeof(int), 1, in) != 1 ||
233 fread(&now_id.instance, sizeof(int), 1, in) != 1 ||
234 !readup_str(&ref->file, in) ||
235 fread(&ref->line, sizeof(int), 1, in) != 1)
236 fatal_exit("fread failed");
237 if(verb) printf("read lock %u %u %u %u %s %d\n",
238 (unsigned)prev_id.thr, (unsigned)prev_id.instance,
239 (unsigned)now_id.thr, (unsigned)now_id.instance,
240 ref->file, ref->line);
241 /* find the two locks involved */
242 prev = (struct order_lock*)rbtree_search(all, &prev_id);
243 now = (struct order_lock*)rbtree_search(all, &now_id);
244 /* if not there - insert 'em */
245 if(!prev) prev = insert_lock(all, &prev_id);
246 if(!now) now = insert_lock(all, &now_id);
248 ref->node.key = &prev->id;
249 if(!rbtree_insert(now->smaller, &ref->node)) {
255 /** read input file */
256 static void readinput(rbtree_t* all, char* file)
258 FILE *in = fopen(file, "r");
264 printf("file %s", file);
265 if(!read_header(in)) {
269 while(fread(&fst, sizeof(fst), 1, in) == 1) {
271 read_create(all, in);
272 else read_lock(all, in, fst);
277 /** print cycle message */
278 static void found_cycle(struct lock_ref* visit, int level)
283 printf("Found inconsistent locking order of length %d\n", level);
284 printf("for lock %d %d created %s %d\n",
285 visit->lock->id.thr, visit->lock->id.instance,
286 visit->lock->create_file, visit->lock->create_line);
287 printf("sequence is:\n");
290 struct order_lock* next =
291 p->lock->dfs_next?p->lock->dfs_next->lock:visit->lock;
292 printf("[%d] is locked at line %s %d before lock %d %d\n",
293 i, p->file, p->line, next->id.thr, next->id.instance);
294 printf("[%d] lock %d %d is created at %s %d\n",
295 i, next->id.thr, next->id.instance,
296 next->create_file, next->create_line);
298 p = p->lock->dfs_next;
299 if(p && p->lock == visit->lock)
304 /** Detect cycle by comparing visited now with all (unvisited) bigger nodes */
305 static int detect_cycle(struct lock_ref* visit, struct lock_ref* from)
307 struct lock_ref* p = from;
309 if(p->lock == visit->lock)
311 p = p->lock->dfs_next;
316 /** recursive function to depth first search for cycles.
317 * @param visit: the lock visited at this step.
318 * its dfs_next pointer gives the visited lock up in recursion.
319 * same as lookfor at level 0.
320 * @param level: depth of recursion. 0 is start.
321 * @param from: search for matches from unvisited node upwards.
323 static void search_cycle(struct lock_ref* visit, int level,
324 struct lock_ref* from)
326 struct lock_ref* ref;
327 /* check for cycle */
328 if(detect_cycle(visit, from) && level != 0) {
329 found_cycle(visit, level);
330 fatal_exit("found lock order cycle");
333 if(!visit->lock->visited)
335 if(verb > 1) fprintf(stderr, "[%d] visit lock %u %u %s %d\n", level,
336 (unsigned)visit->lock->id.thr,
337 (unsigned)visit->lock->id.instance,
338 visit->lock->create_file, visit->lock->create_line);
339 RBTREE_FOR(ref, struct lock_ref*, visit->lock->smaller) {
340 ref->lock->dfs_next = visit;
341 search_cycle(ref, level+1, from);
343 visit->lock->visited = 1;
346 /** Check ordering of one lock */
347 static void check_order_lock(struct order_lock* lock)
349 struct lock_ref start;
350 if(lock->visited) return;
352 start.node.key = &lock->id;
354 start.file = lock->create_file;
355 start.line = lock->create_line;
357 if(!lock->create_file)
358 log_err("lock %u %u does not have create info",
359 (unsigned)lock->id.thr, (unsigned)lock->id.instance);
361 /* depth first search to find cycle with this lock at head */
362 lock->dfs_next = NULL;
363 search_cycle(&start, 0, &start);
366 /** Check ordering of locks */
367 static void check_order(rbtree_t* all_locks)
369 /* check each lock */
370 struct order_lock* lock;
372 RBTREE_FOR(lock, struct order_lock*, all_locks) {
374 printf("[%d/%d] Checking lock %d %d %s %d\n",
375 i, (int)all_locks->count,
376 lock->id.thr, lock->id.instance,
377 lock->create_file, lock->create_line);
378 else if (i % ((all_locks->count/75)<1?1:all_locks->count/75)
380 fprintf(stderr, ".");
382 check_order_lock(lock);
384 fprintf(stderr, "\n");
387 /** main program to verify all traces passed */
389 main(int argc, char* argv[])
393 time_t starttime = time(NULL);
398 log_init(NULL, 0, NULL);
399 log_ident_set("lock-verify");
401 all_locks = rbtree_create(order_lock_cmp);
404 /* read the input files */
405 for(i=1; i<argc; i++) {
406 readinput(all_locks, argv[i]);
410 check_order(all_locks);
412 /* do not free a thing, OS will do it */
413 printf("checked %d locks in %d seconds with %d errors.\n",
414 (int)all_locks->count, (int)(time(NULL)-starttime),
416 if(errors_detected) return 1;