libkmod: Add helper function to iterate lookup options

The CHECK_ERR_AND_FINISH macro with conditional code flow changes has
been a source of bugs. Get rid of it replacing with a helper function
to iterate an array of lookup functions. This helper may also be useful
in future to create different lookup APIs in libkmod.

Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>

diff --git a/libkmod/libkmod-module.c b/libkmod/libkmod-module.c
index 1b59c3c4ef1d3cf3756d77331caa3636452e0bf5..7cb6d26b8d963ccd231aecc62827fcfddf10ec50 100644 (file)
--- a/libkmod/libkmod-module.c
+++ b/libkmod/libkmod-module.c
@@ -499,13 +499,26 @@ KMOD_EXPORT struct kmod_module *kmod_module_ref(struct kmod_module *mod)
        return mod;
 }
 
-#define CHECK_ERR_AND_FINISH(_err, _label_err, _list, label_finish)    \
-       do {                                                            \
-               if ((_err) < 0)                                         \
-                       goto _label_err;                                \
-               if (*(_list) != NULL)                                   \
-                       goto finish;                                    \
-       } while (0)
+typedef int (*lookup_func)(struct kmod_ctx *ctx, const char *name, struct kmod_list **list) __attribute__((nonnull(1, 2, 3)));
+
+static int __kmod_module_new_from_lookup(struct kmod_ctx *ctx, const lookup_func lookup[],
+                                        size_t lookup_count, const char *s,
+                                        struct kmod_list **list)
+{
+       unsigned int i;
+
+       for (i = 0; i < lookup_count; i++) {
+               int err;
+
+               err = lookup[i](ctx, s, list);
+               if (err < 0 && err != -ENOSYS)
+                       return err;
+               else if (*list != NULL)
+                       return 0;
+       }
+
+       return 0;
+}
 
 /**
  * kmod_module_new_from_lookup:
@@ -538,8 +551,17 @@ KMOD_EXPORT int kmod_module_new_from_lookup(struct kmod_ctx *ctx,
                                                const char *given_alias,
                                                struct kmod_list **list)
 {
-       int err;
+       const lookup_func lookup[] = {
+               kmod_lookup_alias_from_config,
+               kmod_lookup_alias_from_moddep_file,
+               kmod_lookup_alias_from_symbols_file,
+               kmod_lookup_alias_from_commands,
+               kmod_lookup_alias_from_aliases_file,
+               kmod_lookup_alias_from_builtin_file,
+               kmod_lookup_alias_from_kernel_builtin_file,
+       };
        char alias[PATH_MAX];
+       int err;
 
        if (ctx == NULL || given_alias == NULL)
                return -ENOENT;
@@ -556,48 +578,18 @@ KMOD_EXPORT int kmod_module_new_from_lookup(struct kmod_ctx *ctx,
 
        DBG(ctx, "input alias=%s, normalized=%s\n", given_alias, alias);
 
-       /* Aliases from config file override all the others */
-       err = kmod_lookup_alias_from_config(ctx, alias, list);
-       CHECK_ERR_AND_FINISH(err, fail, list, finish);
+       err = __kmod_module_new_from_lookup(ctx, lookup, sizeof(lookup),
+                                           alias, list);
 
-       DBG(ctx, "lookup modules.dep %s\n", alias);
-       err = kmod_lookup_alias_from_moddep_file(ctx, alias, list);
-       CHECK_ERR_AND_FINISH(err, fail, list, finish);
-
-       DBG(ctx, "lookup modules.symbols %s\n", alias);
-       err = kmod_lookup_alias_from_symbols_file(ctx, alias, list);
-       CHECK_ERR_AND_FINISH(err, fail, list, finish);
-
-       DBG(ctx, "lookup install and remove commands %s\n", alias);
-       err = kmod_lookup_alias_from_commands(ctx, alias, list);
-       CHECK_ERR_AND_FINISH(err, fail, list, finish);
-
-       DBG(ctx, "lookup modules.aliases %s\n", alias);
-       err = kmod_lookup_alias_from_aliases_file(ctx, alias, list);
-       CHECK_ERR_AND_FINISH(err, fail, list, finish);
-
-       DBG(ctx, "lookup modules.builtin %s\n", alias);
-       err = kmod_lookup_alias_from_builtin_file(ctx, alias, list);
-       CHECK_ERR_AND_FINISH(err, fail, list, finish);
-
-       DBG(ctx, "lookup modules.builtin.modinfo %s\n", alias);
-       err = kmod_lookup_alias_from_kernel_builtin_file(ctx, alias, list);
-       /* Optional index missing, ignore */
-       if (err == -ENOSYS)
-               err = 0;
-       CHECK_ERR_AND_FINISH(err, fail, list, finish);
+       DBG(ctx, "lookup=%s found=%d\n", alias, err >= 0 && *list);
 
+       if (err < 0) {
+               kmod_module_unref_list(*list);
+               *list = NULL;
+       }
 
-finish:
-       DBG(ctx, "lookup %s matches=%d, list=%p\n", alias, err, *list);
-       return err > 0 ? 0 : err;
-fail:
-       DBG(ctx, "Failed to lookup %s\n", alias);
-       kmod_module_unref_list(*list);
-       *list = NULL;
        return err;
 }
-#undef CHECK_ERR_AND_FINISH
 
 /**
  * kmod_module_unref_list: