On Mon, Jul 30, 2012 at 3:18 PM, Ben Pfaff <b...@nicira.com> wrote:
> As the database is being transitioned from /etc to /var, there is a symlink
> from the old to the new location for the database and a symlink for its
> lockfile. This works OK, but it would be more user-friendly to still work
> correctly in case the symlink for the lockfile isn't there (since its
> existence is non-obvious), so this commit implements that behavior.
>
> Signed-off-by: Ben Pfaff <b...@nicira.com>
> ---
> lib/lockfile.c | 29 +++++++++++++++++++++--------
> tests/lockfile.at | 1 +
> tests/test-lockfile.c | 30 ++++++++++++++++++++++++++++++
> 3 files changed, 52 insertions(+), 8 deletions(-)
>
> diff --git a/lib/lockfile.c b/lib/lockfile.c
> index c55be66..7ac3465 100644
> --- a/lib/lockfile.c
> +++ b/lib/lockfile.c
> @@ -59,16 +59,29 @@ static int lockfile_try_lock(const char *name, bool
> block,
> struct lockfile **lockfilep);
>
> /* Returns the name of the lockfile that would be created for locking a
> file
> - * named 'file_name'. The caller is responsible for freeing the returned
> - * name, with free(), when it is no longer needed. */
> + * named 'filename_'. The caller is responsible for freeing the returned
> name,
> + * with free(), when it is no longer needed. */
> char *
> -lockfile_name(const char *file_name)
> +lockfile_name(const char *filename_)
> {
> - const char *slash = strrchr(file_name, '/');
> - return (slash
> - ? xasprintf("%.*s/.%s.~lock~",
> - (int) (slash - file_name), file_name, slash + 1)
> - : xasprintf(".%s.~lock~", file_name));
> + char *filename;
> + const char *slash;
> + char *lockname;
> +
> + /* If 'filename_' is a symlink, base the name of the lockfile on the
> + * symlink's target rather than the name of the symlink. That way,
> if a
> + * file is symlinked, but there is no symlink for its lockfile, then
> there
> + * is only a single lockfile for both the source and the target of the
> + * symlink, not one for each. */
> + filename = follow_symlinks(filename_);
> + slash = strrchr(filename, '/');
> + lockname = (slash
> + ? xasprintf("%.*s/.%s.~lock~",
> + (int) (slash - filename), filename, slash + 1)
> + : xasprintf(".%s.~lock~", filename));
> + free(filename);
> +
> + return lockname;
> }
>
> /* Locks the configuration file against modification by other processes
> and
> diff --git a/tests/lockfile.at b/tests/lockfile.at
> index 1fa0342..602cfab 100644
> --- a/tests/lockfile.at
> +++ b/tests/lockfile.at
> @@ -19,3 +19,4 @@ CHECK_LOCKFILE([lock_timeout_gets_the_lock], [1])
> CHECK_LOCKFILE([lock_timeout_runs_out], [1])
> CHECK_LOCKFILE([lock_multiple], [0])
> CHECK_LOCKFILE([lock_symlink], [0])
> +CHECK_LOCKFILE([lock_symlink_to_dir], [0])
> diff --git a/tests/test-lockfile.c b/tests/test-lockfile.c
> index 808ed1e..412010b 100644
> --- a/tests/test-lockfile.c
> +++ b/tests/test-lockfile.c
> @@ -249,6 +249,35 @@ run_lock_symlink(void)
> CHECK(S_ISREG(s.st_mode) != 0, 1);
> }
>
> +/* Checks that locking a file that is itself a symlink yields a lockfile
> in the
> + * directory that the symlink points to, named for the target of the
> + * symlink.
> + *
> + * (That is, if "a" is a symlink to "dir/b", then "a"'s lockfile is named
> + * "dir/.b.~lock".) */
> +static void
> +run_lock_symlink_to_dir(void)
> +{
> + struct lockfile *a, *dummy;
> + struct stat s;
> +
> + /* Create a symlink "a" pointing to "dir/b". */
> + CHECK(mkdir("dir", 0700), 0);
> + CHECK(symlink("dir/b", "a"), 0);
> + CHECK(lstat("a", &s), 0);
> + CHECK(S_ISLNK(s.st_mode) != 0, 1);
> +
> + /* Lock 'a'. */
> + CHECK(lockfile_lock("a", 0, &a), 0);
> + CHECK(lstat("dir/.b.~lock~", &s), 0);
> + CHECK(S_ISREG(s.st_mode) != 0, 1);
> + CHECK(lstat(".a.~lock~", &s), -1);
> + CHECK(errno, ENOENT);
> + CHECK(lockfile_lock("dir/b", 0, &dummy), EDEADLK);
> +
> + lockfile_unlock(a);
> +}
> +
> static void
> run_help(void)
> {
> @@ -275,6 +304,7 @@ static const struct test tests[] = {
> TEST(lock_timeout_runs_out),
> TEST(lock_multiple),
> TEST(lock_symlink),
> + TEST(lock_symlink_to_dir),
> TEST(help),
> { NULL, NULL }
> #undef TEST
> --
> 1.7.2.5
>
> _______________________________________________
> dev mailing list
> dev@openvswitch.org
> http://openvswitch.org/mailman/listinfo/dev
>
Looks good to me.
_______________________________________________
dev mailing list
dev@openvswitch.org
http://openvswitch.org/mailman/listinfo/dev
