kmodloader: add modinfo support for builtin modules

Enable parsing of 'modules.builtin.modinfo' for better handling of builtin
modules, including support for aliases and showing basic builtin module
details, e.g.

  root@OpenWrt:/# modinfo unix
  name:           unix
  filename:       (builtin)
  alias:          net-pf-1
  license:        GPL

  root@OpenWrt:/# modprobe net-pf-1 && echo SUCCESS || echo FAIL
  SUCCESS

Signed-off-by: Tony Ambardar <itugrok@yahoo.com>

diff --git a/kmodloader.c b/kmodloader.c
index 179517edd21bdb1dc51a206222a2042d1f7f7afd..49327a9d0a4f03ae81fdb53be0cf625d9e39c1d5 100644 (file)
--- a/kmodloader.c
+++ b/kmodloader.c
@@ -41,6 +41,7 @@
 
 #define DEF_MOD_PATH "/modules/%s/"
 #define MOD_BUILTIN "modules.builtin"
+#define MOD_BUILTIN_MODINFO "modules.builtin.modinfo"
 /* duplicated from in-kernel include/linux/module.h */
 #define MODULE_NAME_LEN (64 - sizeof(unsigned long))
 
@@ -365,33 +366,55 @@ out:
 
 static struct module* get_module_info(const char *module, const char *name)
 {
-       int fd = open(module, O_RDONLY);
+       const bool is_builtin = (module == NULL);
        unsigned int offset, size;
        char *map = MAP_FAILED, *strings, *dep = NULL;
        const char **aliases = NULL;
        const char **aliasesr;
-       int naliases = 0;
+       const char *mpath = NULL;
+       char path[350], **f;
+       int fd = -1, naliases = 0;
        struct module *m = NULL;
        struct stat s;
 
+       if (is_builtin)
+               for (f = module_folders; *f; f++) {
+                       snprintf(path, sizeof(path), "%s%s", *f, MOD_BUILTIN_MODINFO);
+                       if (!stat(path, &s) && S_ISREG(s.st_mode)) {
+                               mpath = path;
+                               break;
+                       }
+               }
+       else
+               mpath = module;
+
+       if (!mpath) {
+               ULOG_ERR("cannot find modinfo path of module - %s\n", name);
+               goto out;
+       }
+
+       fd = open(mpath, O_RDONLY);
        if (fd < 0) {
-               ULOG_ERR("failed to open %s\n", module);
+               ULOG_ERR("failed to open %s\n", mpath);
                goto out;
        }
 
        if (fstat(fd, &s) == -1) {
-               ULOG_ERR("failed to stat %s\n", module);
+               ULOG_ERR("failed to stat %s\n", mpath);
                goto out;
        }
 
        map = mmap(NULL, s.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
        if (map == MAP_FAILED) {
-               ULOG_ERR("failed to mmap %s\n", module);
+               ULOG_ERR("failed to mmap %s\n", mpath);
                goto out;
        }
 
-       if (elf_find_section(map, ".modinfo", &offset, &size)) {
-               ULOG_ERR("failed to load the .modinfo section from %s\n", module);
+       if (is_builtin) {
+               offset = 0;
+               size = s.st_size;
+       } else if (elf_find_section(map, ".modinfo", &offset, &size)) {
+               ULOG_ERR("failed to load the .modinfo section from %s\n", mpath);
                goto out;
        }
 
@@ -404,6 +427,16 @@ static struct module* get_module_info(const char *module, const char *name)
                        strings++;
                if (strings >= map + offset + size)
                        break;
+               if (is_builtin) {
+                       sep = strstr(strings, ".");
+                       if (!sep)
+                               break;
+                       if (strlen(name) == (sep - strings) &&
+                           !strncmp(strings, name, sep - strings))
+                               strings = sep + 1;
+                       else
+                               goto next_string;
+               }
                sep = strstr(strings, "=");
                if (!sep)
                        break;
@@ -421,13 +454,14 @@ static struct module* get_module_info(const char *module, const char *name)
                        aliases = aliasesr;
                        aliases[naliases++] = sep;
                }
+next_string:
                strings = &sep[strlen(sep)];
        }
 
-       m = alloc_module(name, aliases, naliases, dep, s.st_size);
+       m = alloc_module(name, aliases, naliases, dep, is_builtin ? 0 : s.st_size);
 
        if (m)
-               m->state = SCANNED;
+               m->state = is_builtin ? BUILTIN : SCANNED;
 
 out:
        if (map != MAP_FAILED)
@@ -475,13 +509,11 @@ static int scan_builtin_modules(void)
                        ULOG_WARN("found duplicate builtin module %s\n", name);
                        continue;
                }
-               m = alloc_module(name, NULL, 0, NULL, 0);
+               m = get_module_info(NULL, name);
                if (!m) {
-                       ULOG_ERR("failed to allocate memory for module\n");
+                       ULOG_ERR("failed to find info for builtin module %s\n", name);
                        goto err;
                }
-
-               m->state = BUILTIN;
        }
 out:
        rv = 0;
@@ -552,40 +584,63 @@ static int scan_module_folders(void)
        return rv;
 }
 
-static int print_modinfo(char *module)
+static int print_modinfo(const struct module *m)
 {
-       int fd = open(module, O_RDONLY);
+       const bool is_builtin = (m->state == BUILTIN);
        unsigned int offset, size;
        struct param *p;
        struct stat s;
-       char *map = MAP_FAILED, *strings;
-       int rv = -1;
+       char *map = MAP_FAILED, *strings, **f;
+       char path[350], *mpath = NULL;
+       int fd, rv = -1;
 
        LIST_HEAD(params);
 
+       if (is_builtin)
+               for (f = module_folders; *f; f++) {
+                       snprintf(path, sizeof(path), "%s%s", *f, MOD_BUILTIN_MODINFO);
+                       if (!stat(path, &s) && S_ISREG(s.st_mode)) {
+                               mpath = path;
+                               break;
+                       }
+               }
+       else
+               mpath = get_module_path(m->name);
+
+       if (!mpath) {
+               ULOG_ERR("cannot find modinfo path of module - %s\n", m->name);
+               return -1;
+       }
+
+       fd = open(mpath, O_RDONLY);
        if (fd < 0) {
-               ULOG_ERR("failed to open %s\n", module);
+               ULOG_ERR("failed to open %s\n", mpath);
                goto out;
        }
 
        if (fstat(fd, &s) == -1) {
-               ULOG_ERR("failed to stat %s\n", module);
+               ULOG_ERR("failed to stat %s\n", mpath);
                goto out;
        }
 
        map = mmap(NULL, s.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
        if (map == MAP_FAILED) {
-               ULOG_ERR("failed to mmap %s\n", module);
+               ULOG_ERR("failed to mmap %s\n", mpath);
                goto out;
        }
 
-       if (elf_find_section(map, ".modinfo", &offset, &size)) {
-               ULOG_ERR("failed to load the .modinfo section from %s\n", module);
+       if (is_builtin) {
+               offset = 0;
+               size = s.st_size;
+       } else if (elf_find_section(map, ".modinfo", &offset, &size)) {
+               ULOG_ERR("failed to load the .modinfo section from %s\n", mpath);
                goto out;
        }
 
        strings = map + offset;
-       printf("module:\t\t%s\n", module);
+       if (is_builtin)
+               printf("name:\t\t%s\n", m->name);
+       printf("filename:\t%s\n", is_builtin ? "(builtin)" : mpath);
        while (true) {
                char *pname, *pdata;
                char *dup = NULL;
@@ -595,6 +650,16 @@ static int print_modinfo(char *module)
                        strings++;
                if (strings >= map + offset + size)
                        break;
+               if (is_builtin) {
+                       sep = strstr(strings, ".");
+                       if (!sep)
+                               break;
+                       if (strlen(m->name) == (sep - strings) &&
+                           !strncmp(strings, m->name, sep - strings))
+                               strings = sep + 1;
+                       else
+                               goto next_string;
+               }
                sep = strstr(strings, "=");
                if (!sep)
                        break;
@@ -631,6 +696,7 @@ static int print_modinfo(char *module)
                        else
                                p->desc = pdata;
                }
+next_string:
                strings = &sep[strlen(sep)];
                if (dup)
                        free(dup);
@@ -977,6 +1043,9 @@ static int main_modinfo(int argc, char **argv)
        if (scan_module_folders())
                return -1;
 
+       if (scan_builtin_modules())
+               return -1;
+
        name = get_module_name(argv[1]);
        m = find_module(name);
        if (!m) {
@@ -984,13 +1053,7 @@ static int main_modinfo(int argc, char **argv)
                return -1;
        }
 
-       name = get_module_path(m->name);
-       if (!name) {
-               ULOG_ERR("cannot find path of module - %s\n", m->name);
-               return -1;
-       }
-
-       print_modinfo(name);
+       print_modinfo(m);
 
        return 0;
 }