ccanlint: fix stack smash.

"engla" on IRC reported that ccanlint on linux/powerpc would loop
infinitely calling dep_failed after all tests are run and the score is
output.

Reproduced, and discovered that cannot_run() takes a container_of(),
except our top node is not a struct ccanlint.  The result was harmless on
x86, but set dep_failed to the return address on powerpc, causing that
to be called repeatedly.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/tools/ccanlint/ccanlint.c b/tools/ccanlint/ccanlint.c
index 1a847deb4c7e326203ba33ca2b5189a58c34bece..c0ab02768c4664f4a6940ffad6358405ca83251c 100644 (file)
--- a/tools/ccanlint/ccanlint.c
+++ b/tools/ccanlint/ccanlint.c
@@ -89,10 +89,11 @@ static const char *dep_failed(struct manifest *m)
        return "dependency couldn't run";
 }
 
-static bool cannot_run(struct dgraph_node *node, void *unused)
+static bool cannot_run(struct dgraph_node *node, void *all)
 {
        struct ccanlint *c = container_of(node, struct ccanlint, node);
        c->can_run = dep_failed;
+
        return true;
 }
 
@@ -602,11 +603,11 @@ int main(int argc, char *argv[])
        unsigned int i;
        const char *prefix = "";
        char *cwd = path_cwd(NULL), *dir;
-       struct dgraph_node all;
+       struct ccanlint top;  /* cannot_run may try to set ->can_run */
        const char *override_compiler = NULL, *override_cflags = NULL;
        
        /* Empty graph node to which we attach everything else. */
-       dgraph_init_node(&all);
+       dgraph_init_node(&top.node);
 
        opt_register_early_noarg("--verbose|-v", opt_inc_intval, &verbose,
                                 "verbose mode (up to -vvvv)");
@@ -625,7 +626,8 @@ int main(int argc, char *argv[])
        opt_register_arg("--timeout <milleseconds>", opt_set_uintval,
                         NULL, &timeout,
                         "ignore (terminate) tests that are slower than this");
-       opt_register_arg("-t|--target <testname>", opt_set_target, NULL, &all,
+       opt_register_arg("-t|--target <testname>", opt_set_target, NULL,
+                        &top.node,
                         "only run one test (and its prerequisites)");
        opt_register_arg("--compiler <compiler>", opt_set_const_charp,
                         NULL, &override_compiler, "set the compiler");
@@ -655,7 +657,7 @@ int main(int argc, char *argv[])
        opt_parse(&argc, argv, opt_log_stderr_exit);
 
        if (!targeting)
-               strmap_iterate(&tests, add_to_all, &all);
+               strmap_iterate(&tests, add_to_all, &top.node);
 
        if (argc == 1)
                dir = cwd;
@@ -674,7 +676,7 @@ int main(int argc, char *argv[])
                compiler = override_compiler;
 
        if (argc == 1)
-               pass = test_module(&all, cwd, "", summary);
+               pass = test_module(&top.node, cwd, "", summary);
        else {
                for (i = 1; i < argc; i++) {
                        dir = path_canon(NULL,
@@ -684,8 +686,8 @@ int main(int argc, char *argv[])
                        prefix = path_rel(NULL, take(prefix), dir);
                        prefix = tal_strcat(NULL, take(prefix), ": ");
 
-                       pass &= test_module(&all, dir, prefix, summary);
-                       reset_tests(&all);
+                       pass &= test_module(&top.node, dir, prefix, summary);
+                       reset_tests(&top.node);
                }
        }
        return pass ? 0 : 1;