modprobe: rework/speedup by Timo Teras (timo.teras AT iki.fi)

function                                             old     new   delta
load_modules_dep                                       -     175    +175
helper_get_module                                      -     106    +106
gather_options                                         -      89     +89
add_probe                                              -      67     +67
config_file_action                                   345     388     +43
get_or_add_modentry                                    -      10     +10
loaded                                                 4       -      -4
read_config                                          239     234      -5
llist_find                                            34       -     -34
add_option                                            60       -     -60
modprobe_main                                        567     494     -73
do_modprobe                                          601     273    -328
------------------------------------------------------------------------------
(add/remove: 5/3 grow/shrink: 1/3 up/down: 490/-504)          Total: -14 bytes
   text    data     bss     dec     hex filename
 816778     476    7888  825142   c9736 busybox_old
 816768     476    7880  825124   c9724 busybox_unstripped

1 files changed, 217 insertions, 145 deletions

diff --git a/modutils/modprobe.c b/modutils/modprobe.c
index 945483327..a5ade2add 100644
--- a/modutils/modprobe.c
+++ b/modutils/modprobe.c
@@ -13,26 +13,22 @@
 #include <sys/utsname.h>
 #include <fnmatch.h>
 
-struct modprobe_option {
-        char *module;
-        char *option;
+#define MODULE_FLAG_LOADED              0x0001
+#define MODULE_FLAG_NEED_DEPS           0x0002
+//Misnomer? Seems to mean "was seen in modules.dep":
+#define MODULE_FLAG_EXISTS              0x0004
+#define MODULE_FLAG_BLACKLISTED         0x0008
+
+struct module_entry { /* I'll call it ME. */
+        unsigned flags;
+        char *modname; /* stripped of /path/, .ext and s/-/_/g */
+        const char *probed_name; /* verbatim as seen on cmdline */
+        llist_t *aliases; /* strings. aliases from config files */
+        llist_t *options; /* strings. options from config files */
+        llist_t *deps; /* strings. modules we depend on */
 };
 
-struct modprobe_conf {
-        char probename[MODULE_NAME_LEN];
-        llist_t *options;
-        llist_t *aliases;
-#if ENABLE_FEATURE_MODPROBE_BLACKLIST
-#define add_to_blacklist(conf, name) llist_add_to(&conf->blacklist, name)
-#define check_blacklist(conf, name) (llist_find(conf->blacklist, name) == NULL)
-        llist_t *blacklist;
-#else
-#define add_to_blacklist(conf, name) do {} while (0)
-#define check_blacklist(conf, name) (1)
-#endif
-};
-
-#define MODPROBE_OPTS   "acdlnrt:VC:" USE_FEATURE_MODPROBE_BLACKLIST("b")
+#define MODPROBE_OPTS  "acdlnrt:VC:" USE_FEATURE_MODPROBE_BLACKLIST("b")
 enum {
         MODPROBE_OPT_INSERT_ALL = (INSMOD_OPT_UNUSED << 0), /* a */
         MODPROBE_OPT_DUMP_ONLY  = (INSMOD_OPT_UNUSED << 1), /* c */
@@ -46,30 +42,75 @@ enum {
         MODPROBE_OPT_BLACKLIST  = (INSMOD_OPT_UNUSED << 9) * ENABLE_FEATURE_MODPROBE_BLACKLIST,
 };
 
-static llist_t *loaded;
+struct globals {
+        llist_t *db; /* MEs of all modules ever seen (caching for speed) */
+        llist_t *probes; /* MEs of module(s) requested on cmdline */
+        llist_t *cmdline_mopts; /* strings. module options (from cmdline) */
+        int num_deps; /* what is this? */
+        /* bool. "Did we have 'symbol:FOO' requested on cmdline?" */
+        smallint need_symbols;
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define INIT_G() do { } while (0)
 
-static int read_config(struct modprobe_conf *conf, const char *path);
 
-static void add_option(llist_t **all_opts, const char *module, const char *opts)
+static int read_config(const char *path);
+
+static struct module_entry *helper_get_module(const char *module, int create)
 {
-        struct modprobe_option *o;
+        char modname[MODULE_NAME_LEN];
+        struct module_entry *e;
+        llist_t *l;
+
+        filename2modname(module, modname);
+        for (l = G.db; l != NULL; l = l->link) {
+                e = (struct module_entry *) l->data;
+                if (strcmp(e->modname, modname) == 0)
+                        return e;
+        }
+        if (!create)
+                return NULL;
 
-        o = xzalloc(sizeof(struct modprobe_option));
-        if (module)
-                o->module = filename2modname(module, NULL);
-        o->option = xstrdup(opts);
-        llist_add_to(all_opts, o);
+        e = xzalloc(sizeof(*e));
+        e->modname = xstrdup(modname);
+        llist_add_to(&G.db, e);
+
+        return e;
+}
+static struct module_entry *get_or_add_modentry(const char *module)
+{
+        return helper_get_module(module, 1);
+}
+static struct module_entry *get_modentry(const char *module)
+{
+        return helper_get_module(module, 0);
+}
+
+static void add_probe(const char *name)
+{
+        struct module_entry *m;
+
+        m = get_or_add_modentry(name);
+        m->probed_name = name;
+        m->flags |= MODULE_FLAG_NEED_DEPS;
+        llist_add_to(&G.probes, m);
+
+        G.num_deps++;
+        if (ENABLE_FEATURE_MODUTILS_SYMBOLS
+         && strncmp(m->modname, "symbol:", 7) == 0)
+                G.need_symbols = 1;
 }
 
 static int FAST_FUNC config_file_action(const char *filename,
                                         struct stat *statbuf UNUSED_PARAM,
-                                        void *userdata,
+                                        void *userdata UNUSED_PARAM,
                                         int depth UNUSED_PARAM)
 {
-        struct modprobe_conf *conf = (struct modprobe_conf *) userdata;
         RESERVE_CONFIG_BUFFER(modname, MODULE_NAME_LEN);
-        char *tokens[3];
+        char *tokens[3], *rmod;
         parser_t *p;
+        llist_t *l;
+        struct module_entry *m;
         int rc = TRUE;
 
         if (bb_basename(filename)[0] == '.')
@@ -82,20 +123,39 @@ static int FAST_FUNC config_file_action(const char *filename,
         }
 
         while (config_read(p, tokens, 3, 2, "# \t", PARSE_NORMAL)) {
+//Use index_in_strings?
                 if (strcmp(tokens[0], "alias") == 0) {
                         filename2modname(tokens[1], modname);
-                        if (tokens[2] &&
-                            fnmatch(modname, conf->probename, 0) == 0)
-                                llist_add_to(&conf->aliases,
-                                        filename2modname(tokens[2], NULL));
+                        if (tokens[2] == NULL)
+                                continue;
+
+                        for (l = G.probes; l != NULL; l = l->link) {
+                                m = (struct module_entry *) l->data;
+                                if (fnmatch(modname, m->modname, 0) != 0)
+                                        continue;
+                                rmod = filename2modname(tokens[2], NULL);
+                                llist_add_to(&m->aliases, rmod);
+
+                                if (m->flags & MODULE_FLAG_NEED_DEPS) {
+                                        m->flags &= ~MODULE_FLAG_NEED_DEPS;
+                                        G.num_deps--;
+                                }
+
+                                m = get_or_add_modentry(rmod);
+                                m->flags |= MODULE_FLAG_NEED_DEPS;
+                                G.num_deps++;
+                        }
                 } else if (strcmp(tokens[0], "options") == 0) {
-                        if (tokens[2])
-                                add_option(&conf->options, tokens[1], tokens[2]);
+                        if (tokens[2] == NULL)
+                                continue;
+                        m = get_or_add_modentry(tokens[1]);
+                        llist_add_to(&m->options, xstrdup(tokens[2]));
                 } else if (strcmp(tokens[0], "include") == 0) {
-                        read_config(conf, tokens[1]);
-                } else if (ENABLE_FEATURE_MODPROBE_BLACKLIST &&
-                           strcmp(tokens[0], "blacklist") == 0) {
-                        add_to_blacklist(conf, xstrdup(tokens[1]));
+                        read_config(tokens[1]);
+                } else if (ENABLE_FEATURE_MODPROBE_BLACKLIST
+                 && strcmp(tokens[0], "blacklist") == 0
+                ) {
+                        get_or_add_modentry(tokens[1])->flags |= MODULE_FLAG_BLACKLISTED;
                 }
         }
         config_close(p);
@@ -104,186 +164,198 @@ error:
         return rc;
 }
 
-static int read_config(struct modprobe_conf *conf, const char *path)
+static int read_config(const char *path)
 {
         return recursive_action(path, ACTION_RECURSE | ACTION_QUIET,
-                                config_file_action, NULL, conf, 1);
+                                config_file_action, NULL, NULL, 1);
 }
 
-static char *gather_options(llist_t *first, const char *module, int usecmdline)
+static char *gather_options(char *opts, llist_t *o)
 {
-        struct modprobe_option *opt;
-        llist_t *n;
-        char *opts = xstrdup("");
-        int optlen = 0;
+        int optlen;
 
-        for (n = first; n != NULL; n = n->link) {
-                opt = (struct modprobe_option *) n->data;
+        if (opts == NULL)
+                opts = xstrdup("");
+        optlen = strlen(opts);
 
-                if (opt->module == NULL && !usecmdline)
-                        continue;
-                if (opt->module != NULL && strcmp(opt->module, module) != 0)
-                        continue;
-
-                opts = xrealloc(opts, optlen + strlen(opt->option) + 2);
-                optlen += sprintf(opts + optlen, "%s ", opt->option);
+        for (; o != NULL; o = o->link) {
+                opts = xrealloc(opts, optlen + strlen(o->data) + 2);
+                optlen += sprintf(opts + optlen, "%s ", o->data);
         }
         return opts;
 }
 
-static int do_modprobe(struct modprobe_conf *conf, const char *module)
+static int do_modprobe(struct module_entry *m)
 {
-        RESERVE_CONFIG_BUFFER(modname, MODULE_NAME_LEN);
-        llist_t *deps = NULL;
-        char *fn, *options, *colon = NULL, *tokens[2];
-        parser_t *p;
+        struct module_entry *m2;
+        char *fn, *options;
         int rc = -1;
 
-        p = config_open2(CONFIG_DEFAULT_DEPMOD_FILE, fopen_for_read);
-        /* Modprobe does not work at all without modprobe.dep,
-         * even if the full module name is given. Returning error here
-         * was making us later confuse user with this message:
-         * "module /full/path/to/existing/file/module.ko not found".
-         * It's better to die immediately, with good message: */
-        if (p == NULL)
-                bb_perror_msg_and_die("can't open '%s'", CONFIG_DEFAULT_DEPMOD_FILE);
-
-        while (config_read(p, tokens, 2, 1, "# \t", PARSE_NORMAL)) {
-                colon = last_char_is(tokens[0], ':');
-                if (colon == NULL)
-                        continue;
-
-                filename2modname(tokens[0], modname);
-                if (strcmp(modname, module) == 0)
-                        break;
-
-                colon = NULL;
-        }
-        if (colon == NULL)
-                goto error_not_found;
-
-        colon[0] = '\0';
-        llist_add_to(&deps, xstrdup(tokens[0]));
-        if (tokens[1])
-                string_to_llist(tokens[1], &deps, " ");
+        if (!(m->flags & MODULE_FLAG_EXISTS))
+                return -ENOENT;
 
         if (!(option_mask32 & MODPROBE_OPT_REMOVE))
-                deps = llist_rev(deps);
+                m->deps = llist_rev(m->deps);
 
         rc = 0;
-        while (deps && rc == 0) {
-                fn = llist_pop(&deps);
-                filename2modname(fn, modname);
+        while (m->deps && rc == 0) {
+                fn = llist_pop(&m->deps);
+                m2 = get_or_add_modentry(fn);
                 if (option_mask32 & MODPROBE_OPT_REMOVE) {
-                        if (bb_delete_module(modname, O_EXCL) != 0)
+                        if (bb_delete_module(m->modname, O_EXCL) != 0)
                                 rc = errno;
-                } else if (llist_find(loaded, modname) == NULL) {
-                        options = gather_options(conf->options, modname,
-                                                 strcmp(modname, module) == 0);
+                } else if (!(m2->flags & MODULE_FLAG_LOADED)) {
+                        options = gather_options(NULL, m2->options);
+                        if (m == m2)
+                                options = gather_options(options, G.cmdline_mopts);
+//TODO: looks like G.cmdline_mopts can contain either NULL or just one string, not more?
                         rc = bb_init_module(fn, options);
                         if (rc == 0)
-                                llist_add_to(&loaded, xstrdup(modname));
+                                m2->flags |= MODULE_FLAG_LOADED;
                         free(options);
                 }
 
                 free(fn);
         }
 
- error_not_found:
-        config_close(p);
-
-        if (rc > 0 && !(option_mask32 & INSMOD_OPT_SILENT))
+        if (rc > 0 && !(option_mask32 & INSMOD_OPT_SILENT)) {
                 bb_error_msg("failed to %sload module %s: %s",
-                             (option_mask32 & MODPROBE_OPT_REMOVE) ? "un" : "",
-                             module, moderror(rc));
+                        (option_mask32 & MODPROBE_OPT_REMOVE) ? "un" : "",
+                        m->probed_name ? m->probed_name : m->modname,
+                        moderror(rc)
+                );
+        }
 
-        RELEASE_CONFIG_BUFFER(modname);
         return rc;
 }
 
+static void load_modules_dep(void)
+{
+        struct module_entry *m;
+        char *colon, *tokens[2];
+        parser_t *p;
+
+        p = config_open2(CONFIG_DEFAULT_DEPMOD_FILE, xfopen_for_read);
+//Still true?
+        /* Modprobe does not work at all without modprobe.dep,
+         * even if the full module name is given. Returning error here
+         * was making us later confuse user with this message:
+         * "module /full/path/to/existing/file/module.ko not found".
+         * It's better to die immediately, with good message: */
+//      if (p == NULL)
+//              bb_perror_msg_and_die("can't open '%s'", CONFIG_DEFAULT_DEPMOD_FILE);
+
+        while (G.num_deps
+         && config_read(p, tokens, 2, 1, "# \t", PARSE_NORMAL)
+        ) {
+                colon = last_char_is(tokens[0], ':');
+                if (colon == NULL)
+                        continue;
+                *colon = 0;
+
+                m = get_modentry(tokens[0]);
+                if (m == NULL)
+                        continue;
+//Can we skip it too if it is MODULE_FLAG_LOADED?
+
+                m->flags |= MODULE_FLAG_EXISTS;
+                if ((m->flags & MODULE_FLAG_NEED_DEPS) && (m->deps == NULL)) {
+                        G.num_deps--;
+                        llist_add_to(&m->deps, xstrdup(tokens[0]));
+                        if (tokens[1])
+                                string_to_llist(tokens[1], &m->deps, " ");
+                }
+        }
+        config_close(p);
+}
+
 int modprobe_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int modprobe_main(int argc UNUSED_PARAM, char **argv)
 {
         struct utsname uts;
         int rc;
         unsigned opt;
-        llist_t *options = NULL;
+        struct module_entry *me;
 
         opt_complementary = "q-v:v-q";
-        opt = getopt32(argv, INSMOD_OPTS MODPROBE_OPTS INSMOD_ARGS,
-                 NULL, NULL);
+        opt = getopt32(argv, INSMOD_OPTS MODPROBE_OPTS INSMOD_ARGS, NULL, NULL);
         argv += optind;
 
         if (opt & (MODPROBE_OPT_DUMP_ONLY | MODPROBE_OPT_LIST_ONLY |
                                 MODPROBE_OPT_SHOW_ONLY))
                 bb_error_msg_and_die("not supported");
 
-        /* goto modules location */
+        /* Goto modules location */
         xchdir(CONFIG_DEFAULT_MODULES_DIR);
         uname(&uts);
         xchdir(uts.release);
 
         if (!argv[0]) {
                 if (opt & MODPROBE_OPT_REMOVE) {
+                        /* TODO: comment here */
                         if (bb_delete_module(NULL, O_NONBLOCK|O_EXCL) != 0)
                                 bb_perror_msg_and_die("rmmod");
                 }
                 return EXIT_SUCCESS;
         }
-        if (!(opt & MODPROBE_OPT_INSERT_ALL)) {
-                /* If not -a, we have only one module name,
-                 * the rest of parameters are options */
-                add_option(&options, NULL, parse_cmdline_module_options(argv));
-                argv[1] = NULL;
+
+        if (opt & MODPROBE_OPT_INSERT_ALL) {
+                /* Each argument is a module name */
+                do {
+                        add_probe(*argv++);
+                } while (*argv);
+                G.probes = llist_rev(G.probes);
+        } else {
+                /* First argument is module name, rest are parameters */
+                add_probe(argv[0]);
+//TODO: looks like G.cmdline_mopts can contain either NULL or just one string, not more?
+//optimize it them
+                llist_add_to(&G.cmdline_mopts, parse_cmdline_module_options(argv));
         }
 
-        /* cache modules */
+        /* Retrieve module names of already loaded modules */
         {
                 char *s;
                 parser_t *parser = config_open2("/proc/modules", fopen_for_read);
                 while (config_read(parser, &s, 1, 1, "# \t", PARSE_NORMAL & ~PARSE_GREEDY))
-                        llist_add_to(&loaded, xstrdup(s));
+                        get_or_add_modentry(s)->flags |= MODULE_FLAG_LOADED;
                 config_close(parser);
         }
 
-        while (*argv) {
-                const char *arg = *argv;
-                struct modprobe_conf *conf;
-
-                conf = xzalloc(sizeof(*conf));
-                conf->options = options;
-                filename2modname(arg, conf->probename);
-                read_config(conf, "/etc/modprobe.conf");
-                read_config(conf, "/etc/modprobe.d");
-                if (ENABLE_FEATURE_MODUTILS_SYMBOLS
-                 && conf->aliases == NULL
-                 && strncmp(arg, "symbol:", 7) == 0
-                ) {
-                        read_config(conf, "modules.symbols");
-                }
-
-                if (ENABLE_FEATURE_MODUTILS_ALIAS && conf->aliases == NULL)
-                        read_config(conf, "modules.alias");
+        read_config("/etc/modprobe.conf");
+        read_config("/etc/modprobe.d");
+        if (ENABLE_FEATURE_MODUTILS_SYMBOLS && G.need_symbols)
+                read_config("modules.symbols");
+        load_modules_dep();
+        if (ENABLE_FEATURE_MODUTILS_ALIAS && G.num_deps) {
+                read_config("modules.alias");
+                load_modules_dep();
+        }
 
-                if (conf->aliases == NULL) {
+        while ((me = llist_pop(&G.probes)) != NULL) {
+                if (me->aliases == NULL) {
                         /* Try if module by literal name is found; literal
-                         * names are blacklist only if '-b' is given. */
-                        if (!(opt & MODPROBE_OPT_BLACKLIST) ||
-                            check_blacklist(conf, conf->probename)) {
-                                rc = do_modprobe(conf, conf->probename);
+                         * names are blacklisted only if '-b' is given. */
+                        if (!(opt & MODPROBE_OPT_BLACKLIST)
+                         || !(me->flags & MODULE_FLAG_BLACKLISTED)
+                        ) {
+                                rc = do_modprobe(me);
                                 if (rc < 0 && !(opt & INSMOD_OPT_SILENT))
-                                        bb_error_msg("module %s not found", arg);
+                                        bb_error_msg("module %s not found",
+                                                     me->probed_name);
                         }
                 } else {
                         /* Probe all aliases */
-                        while (conf->aliases != NULL) {
-                                char *realname = llist_pop(&conf->aliases);
-                                if (check_blacklist(conf, realname))
-                                        do_modprobe(conf, realname);
+                        do {
+                                char *realname = llist_pop(&me->aliases);
+                                struct module_entry *m2;
+
+                                m2 = get_or_add_modentry(realname);
+                                if (!(m2->flags & MODULE_FLAG_BLACKLISTED))
+                                        do_modprobe(m2);
                                 free(realname);
-                        }
+                        } while (me->aliases != NULL);
                 }
-                argv++;
         }
 
         return EXIT_SUCCESS;