- optional fancy pruning-mode for depmod

1 files changed, 107 insertions, 21 deletions

diff --git a/modutils/depmod.c b/modutils/depmod.c
index e061501f6..b0b09c235 100644
--- a/modutils/depmod.c
+++ b/modutils/depmod.c
@@ -10,15 +10,27 @@
 #define _GNU_SOURCE
 #include <libbb.h>
 #include <sys/utsname.h> /* uname() */
-
+#if ENABLE_DEBUG
+#include <assert.h>
+#define dbg_assert assert
+#else
+#define dbg_assert(stuff) do {} while (0)
+#endif
 /*
  * Theory of operation:
  * - iterate over all modules and record their full path
  * - iterate over all modules looking for "depends=" entries
  *   for each depends, look through our list of full paths and emit if found
  */
+
+typedef struct dep_lst_t {
+        char *name;
+        llist_t *dependencies;
+        struct dep_lst_t *next;
+} dep_lst_t;
+
 struct globals {
-        llist_t *lst; /* modules without their corresponding extension */
+        dep_lst_t *lst; /* modules without their corresponding extension */
         size_t moddir_base_len; /* length of the "-b basedir" */
 };
 #define G (*(struct globals*)&bb_common_bufsiz1)
@@ -28,22 +40,28 @@ struct globals {
 static int fill_lst(const char *modulename, struct stat ATTRIBUTE_UNUSED *sb,
                                         void ATTRIBUTE_UNUSED *data, int ATTRIBUTE_UNUSED depth)
 {
+
         /* We get a file here. If the file does not have ".ko" but an
          * intermittent dentry has, it's just their fault.
          */
-        if (strrstr(modulename, ".ko") != NULL)
-                llist_add_to(&G.lst, xstrdup(modulename + G.moddir_base_len));
+        if (strrstr(modulename, ".ko") != NULL) {
+                dep_lst_t *new = xzalloc(sizeof(dep_lst_t));
+                new->name = xstrdup(modulename + G.moddir_base_len);
+                new->next = G.lst;
+                G.lst = new;
+        }
         return TRUE;
 }
 
 static int fileAction(const char *fname, struct stat *sb,
-                                        void *data, int ATTRIBUTE_UNUSED depth)
+                                        void ATTRIBUTE_UNUSED *data, int ATTRIBUTE_UNUSED depth)
 {
         size_t len = sb->st_size;
         void *the_module;
         char *ptr;
         int fd;
         char *depends, *deps;
+        dep_lst_t *this;
 
         if (strrstr(fname, ".ko") == NULL) /* not a module */
                 goto skip;
@@ -61,40 +79,44 @@ static int fileAction(const char *fname, struct stat *sb,
         close(fd);
         if (the_module == MAP_FAILED)
                 bb_perror_msg_and_die("mmap");
-
         ptr = the_module;
-
-        fprintf((FILE*)data, "%s:", fname + G.moddir_base_len);
+        this = G.lst;
+        do {
+                if (!strcmp(fname + G.moddir_base_len, this->name))
+                        break;
+                this = this->next;
+        } while (this);
+        dbg_assert (this);
 //bb_info_msg("fname='%s'", fname + G.moddir_base_len);
         do {
                 /* search for a 'd' */
                 ptr = memchr(ptr, 'd', len - (ptr - (char*)the_module));
                 if (ptr == NULL) /* no d left, done */
                         goto none;
-                if (strncmp(ptr, "depends=", sizeof("depends=")-1) == 0)
+                if (!strncmp(ptr, "depends=", sizeof("depends=")-1))
                         break;
                 ++ptr;
         } while (1);
         deps = depends = xstrdup (ptr + sizeof("depends=")-1);
 //bb_info_msg(" depends='%s'", depends);
         while (deps) {
-                llist_t * _lst = G.lst;
+                dep_lst_t *all = G.lst;
 
                 ptr = strsep(&deps, ",");
-                while (_lst) {
+                while (all) {
                         /* Compare the recorded filenames ignoring ".ko*" at the end.  */
-                        char *tmp = bb_get_last_path_component_nostrip(_lst->data);
-                        if (strncmp(ptr, tmp, strrstr(tmp, ".ko") - tmp) == 0)
+                        char *tmp = bb_get_last_path_component_nostrip(all->name);
+                        if (!strncmp(ptr, tmp, MAX(strlen(ptr),strrstr(tmp, ".ko") - tmp)))
                                 break; /* found it */
-                        _lst = _lst->link;
+                        all = all->next;
                 }
-                if (_lst) {
-//bb_info_msg("[%s] -> '%s'", (char*)ptr, _lst->data);
-                        fprintf((FILE*)data, " %s", _lst->data);
+                if (all) {
+                        dbg_assert(all->name); /* this cannot be empty */
+//bb_info_msg("[%s] -> '%s'", (char*)ptr, all->name);
+                        llist_add_to_end(&this->dependencies, all->name);
                 }
         }
         free(depends);
-        fprintf((FILE*)data, "\n");
  none:
         munmap(the_module, sb->st_size);
  skip:
@@ -115,11 +137,14 @@ int depmod_main(int ATTRIBUTE_UNUSED argc, char **argv)
                 ARG_F = (1<<4), /* System.map that contains the symbols */
                 ARG_n = (1<<5)  /* dry-run, print to stdout only */
         };
+        INIT_G();
 
         getopt32(argv, "aAb:eF:n", &moddir_base, &system_map);
         argv += optind;
 
-        /* got a version to use? */
+        /* If a version is provided, then that kernel version’s module directory
+         * is used, rather than the current kernel version (as returned by
+         * "uname -r").  */
         if (*argv && (sscanf(*argv, "%d.%d.%d", &ret, &ret, &ret) == 3)) {
                 moddir = concat_path_file(CONFIG_DEFAULT_MODULES_DIR, *argv++);
         } else {
@@ -160,6 +185,9 @@ int depmod_main(int ATTRIBUTE_UNUSED argc, char **argv)
                 else
                         return EXIT_FAILURE;
         }
+#if ENABLE_FEATURE_CLEAN_UP
+        else
+#endif
         do {
                 chp = option_mask32 & ARG_a ? moddir : *argv++;
 
@@ -167,16 +195,74 @@ int depmod_main(int ATTRIBUTE_UNUSED argc, char **argv)
                                 ACTION_RECURSE, /* flags */
                                 fileAction, /* file action */
                                 NULL, /* dir action */
-                                (void*)filedes, /* user data */
+                                NULL, /* user data */
                                 0)) { /* depth */
                         ret = EXIT_FAILURE;
                 }
         } while (!(option_mask32 & ARG_a) && *argv);
 
+        /* modprobe allegedly wants dependencies without duplicates, i.e.
+         * mod1: mod2 mod3
+         * mod2: mod3
+         * mod3:
+         * implies that mod1 directly depends on mod2 and _not_ mod3 as mod3 is
+         * already implicitely pulled in via mod2. This leaves us with:
+         * mod1: mod2
+         * mod2: mod3
+         * mod3:
+         */
+        {
+        dep_lst_t *mods = G.lst;
+#if ENABLE_FEATURE_DEPMOD_PRUNE_FANCY
+        while (mods) {
+                llist_t *deps = mods->dependencies;
+                while (deps) {
+                        dep_lst_t *all = G.lst;
+                        while (all) {
+                                if (!strcmp(all->name, deps->data)) {
+                                        llist_t *implied = all->dependencies;
+                                        while (implied) {
+                                                /* erm, nicer would be to just
+                                                 * llist_unlink(&mods->dependencies, implied)  */
+                                                llist_t *prune = mods->dependencies;
+                                                while (prune) {
+                                                        if (!strcmp(implied->data, prune->data))
+                                                                break;
+                                                        prune = prune->link;
+                                                }
+//if (prune) bb_info_msg("[%s] '%s' implies '%s', removing", mods->name, all->name, implied->data);
+                                                llist_unlink(&mods->dependencies, prune);
+                                                implied = implied->link;
+                                        }
+                                }
+                                all = all->next;
+                        }
+                        deps = deps->link;
+                }
+                mods = mods->next;
+        }
+
+        mods = G.lst;
+#endif
+        /* Finally print them.  */
+        while (mods) {
+                fprintf(filedes, "%s:", mods->name);
+                while (mods->dependencies)
+                        fprintf(filedes, " %s", (char*)llist_pop(&mods->dependencies));
+                fprintf(filedes, "\n");
+                mods = mods->next;
+        }
+        }
+
         if (ENABLE_FEATURE_CLEAN_UP) {
                 fclose_if_not_stdin(filedes);
-                llist_free(G.lst, free);
                 free(moddir);
+                while (G.lst) {
+                        dep_lst_t *old = G.lst;
+                        G.lst = G.lst->next;
+                        free(old->name);
+                        free(old);
+                }
         }
         return ret;
 }