tdb: new test, cleanup old tests by centralizing lock tracking.

[ccan] / ccan / tdb / test / lock-tracking.c

diff --git a/ccan/tdb/test/lock-tracking.c b/ccan/tdb/test/lock-tracking.c
new file mode 100644 (file)
index 0000000..bc4be14
--- /dev/null
+++ b/ccan/tdb/test/lock-tracking.c
@@ -0,0 +1,103 @@
+/* We save the locks so we can reaquire them. */
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <ccan/tap/tap.h>
+
+struct lock {
+       struct lock *next;
+       unsigned int off;
+       unsigned int len;
+       int type;
+};
+static struct lock *locks;
+int locking_errors = 0;
+void (*unlock_callback)(int fd);
+
+int fcntl_with_lockcheck(int fd, int cmd, ... /* arg */ )
+{
+       va_list ap;
+       int ret, arg3;
+       struct flock *fl;
+
+       if (cmd != F_SETLK && cmd != F_SETLKW) {
+               /* This may be totally bogus, but we don't know in general. */
+               va_start(ap, cmd);
+               arg3 = va_arg(ap, int);
+               va_end(ap);
+
+               return fcntl(fd, cmd, arg3);
+       }
+
+       va_start(ap, cmd);
+       fl = va_arg(ap, struct flock *);
+       va_end(ap);
+
+       if (fl->l_type == F_UNLCK) {
+               struct lock **l;
+               struct lock *old = NULL;
+                       
+               for (l = &locks; *l; l = &(*l)->next) {
+                       if ((*l)->off == fl->l_start
+                           && (*l)->len == fl->l_len) {
+                               old = *l;
+                               *l = (*l)->next;
+                               free(old);
+                               break;
+                       }
+               }
+               if (!old) {
+                       diag("Unknown unlock %u@%u",
+                            (int)fl->l_len, (int)fl->l_start);
+                       locking_errors++;
+               }
+       } else {
+               struct lock *new, *i;
+               unsigned int fl_end = fl->l_start + fl->l_len;
+               if (fl->l_len == 0)
+                       fl_end = (unsigned int)-1;
+
+               /* Check for overlaps: we shouldn't do this. */
+               for (i = locks; i; i = i->next) {
+                       unsigned int i_end = i->off + i->len;
+                       if (i->len == 0)
+                               i_end = (unsigned int)-1;
+
+                       if (fl->l_start >= i->off && fl->l_start < i_end)
+                               break;
+                       if (fl_end >= i->off && fl_end < i_end)
+                               break;
+               }
+               if (i) {
+                       diag("%s lock %u@%u overlaps %u@%u",
+                            fl->l_type == F_WRLCK ? "write" : "read",
+                            (int)fl->l_len, (int)fl->l_start,
+                            i->len, (int)i->off);
+                       locking_errors++;
+               }
+               new = malloc(sizeof *new);
+               new->off = fl->l_start;
+               new->len = fl->l_len;
+               new->type = fl->l_type;
+               new->next = locks;
+               locks = new;
+       }
+
+       ret = fcntl(fd, cmd, fl);
+       if (ret == 0 && fl->l_type == F_UNLCK && unlock_callback)
+               unlock_callback(fd);
+       return ret;
+}
+
+int forget_locking(void)
+{
+       unsigned int num = 0;
+       while (locks) {
+               struct lock *next = locks->next;
+               free(locks);
+               locks = next;
+               num++;
+       }
+       return num;
+}