libkmod-config: refactor functions to get config

[thirdparty/kmod.git] / libkmod / libkmod-module.c

/*
 * libkmod - interface to kernel module operations
 *
 * Copyright (C) 2011-2012  ProFUSION embedded systems
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <inttypes.h>
#include <limits.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <string.h>
#include <fnmatch.h>

#include "libkmod.h"
#include "libkmod-private.h"

/**
 * SECTION:libkmod-module
 * @short_description: operate on kernel modules
 */

/**
 * kmod_module:
 *
 * Opaque object representing a module.
 */
struct kmod_module {
        struct kmod_ctx *ctx;
        char *hashkey;
        char *name;
        char *path;
        struct kmod_list *dep;
        char *options;
        const char *install_commands;   /* owned by kmod_config */
        const char *remove_commands;    /* owned by kmod_config */
        char *alias; /* only set if this module was created from an alias */
        int n_dep;
        int refcount;
        struct {
                bool dep : 1;
                bool options : 1;
                bool install_commands : 1;
                bool remove_commands : 1;
        } init;

        /*
         * private field used by kmod_module_get_probe_list() to detect
         * dependency loops
         */
        bool visited : 1;

        /*
         * set by kmod_module_get_probe_list: indicates for probe_insert()
         * whether the module's command and softdep should be ignored
         */
        bool ignorecmd : 1;

        /*
         * if module was created by searching the modules.builtin file, this
         * is set. There's nothing much useful one can do with such a
         * "module", except knowing it's builtin.
         */
        bool builtin : 1;
};

static inline const char *path_join(const char *path, size_t prefixlen,
                                                        char buf[PATH_MAX])
{
        size_t pathlen;

        if (path[0] == '/')
                return path;

        pathlen = strlen(path);
        if (prefixlen + pathlen + 1 >= PATH_MAX)
                return NULL;

        memcpy(buf + prefixlen, path, pathlen + 1);
        return buf;
}

static inline bool module_is_inkernel(struct kmod_module *mod)
{
        int state = kmod_module_get_initstate(mod);

        if (state == KMOD_MODULE_LIVE ||
                        state == KMOD_MODULE_BUILTIN)
                return true;

        return false;
}

int kmod_module_parse_depline(struct kmod_module *mod, char *line)
{
        struct kmod_ctx *ctx = mod->ctx;
        struct kmod_list *list = NULL;
        const char *dirname;
        char buf[PATH_MAX];
        char *p, *saveptr;
        int err = 0, n = 0;
        size_t dirnamelen;

        if (mod->init.dep)
                return mod->n_dep;
        assert(mod->dep == NULL);
        mod->init.dep = true;

        p = strchr(line, ':');
        if (p == NULL)
                return 0;

        *p = '\0';
        dirname = kmod_get_dirname(mod->ctx);
        dirnamelen = strlen(dirname);
        if (dirnamelen + 2 >= PATH_MAX)
                return 0;

        memcpy(buf, dirname, dirnamelen);
        buf[dirnamelen] = '/';
        dirnamelen++;
        buf[dirnamelen] = '\0';

        if (mod->path == NULL) {
                const char *str = path_join(line, dirnamelen, buf);
                if (str == NULL)
                        return 0;
                mod->path = strdup(str);
                if (mod->path == NULL)
                        return 0;
        }

        p++;
        for (p = strtok_r(p, " \t", &saveptr); p != NULL;
                                        p = strtok_r(NULL, " \t", &saveptr)) {
                struct kmod_module *depmod;
                const char *path;

                path = path_join(p, dirnamelen, buf);
                if (path == NULL) {
                        ERR(ctx, "could not join path '%s' and '%s'.\n",
                            dirname, p);
                        goto fail;
                }

                err = kmod_module_new_from_path(ctx, path, &depmod);
                if (err < 0) {
                        ERR(ctx, "ctx=%p path=%s error=%s\n",
                                                ctx, path, strerror(-err));
                        goto fail;
                }

                DBG(ctx, "add dep: %s\n", path);

                list = kmod_list_prepend(list, depmod);
                n++;
        }

        DBG(ctx, "%d dependencies for %s\n", n, mod->name);

        mod->dep = list;
        mod->n_dep = n;
        return n;

fail:
        kmod_module_unref_list(list);
        mod->init.dep = false;
        return err;
}

void kmod_module_set_visited(struct kmod_module *mod, bool visited)
{
        mod->visited = visited;
}

void kmod_module_set_builtin(struct kmod_module *mod, bool builtin)
{
        mod->builtin = builtin;
}

/*
 * Memory layout with alias:
 *
 * struct kmod_module {
 *        hashkey -----.
 *        alias -----. |
 *        name ----. | |
 * }               | | |
 * name <----------' | |
 * alias <-----------' |
 * name\alias <--------'
 *
 * Memory layout without alias:
 *
 * struct kmod_module {
 *        hashkey ---.
 *        alias -----|----> NULL
 *        name ----. |
 * }               | |
 * name <----------'-'
 *
 * @key is "name\alias" or "name" (in which case alias == NULL)
 */
static int kmod_module_new(struct kmod_ctx *ctx, const char *key,
                                const char *name, size_t namelen,
                                const char *alias, size_t aliaslen,
                                struct kmod_module **mod)
{
        struct kmod_module *m;
        size_t keylen;

        m = kmod_pool_get_module(ctx, key);
        if (m != NULL) {
                *mod = kmod_module_ref(m);
                return 0;
        }

        if (alias == NULL)
                keylen = namelen;
        else
                keylen = namelen + aliaslen + 1;

        m = malloc(sizeof(*m) + (alias == NULL ? 1 : 2) * (keylen + 1));
        if (m == NULL) {
                free(m);
                return -ENOMEM;
        }

        memset(m, 0, sizeof(*m));

        m->ctx = kmod_ref(ctx);
        m->name = (char *)m + sizeof(*m);
        memcpy(m->name, key, keylen + 1);
        if (alias == NULL) {
                m->hashkey = m->name;
                m->alias = NULL;
        } else {
                m->name[namelen] = '\0';
                m->alias = m->name + namelen + 1;
                m->hashkey = m->name + keylen + 1;
                memcpy(m->hashkey, key, keylen + 1);
        }

        m->refcount = 1;
        kmod_pool_add_module(ctx, m, m->hashkey);
        *mod = m;

        return 0;
}

/**
 * kmod_module_new_from_name:
 * @ctx: kmod library context
 * @name: name of the module
 * @mod: where to save the created struct kmod_module
 *
 * Create a new struct kmod_module using the module name. @name can not be an
 * alias, file name or anything else; it must be a module name. There's no
 * check if the module exists in the system.
 *
 * This function is also used internally by many others that return a new
 * struct kmod_module or a new list of modules.
 *
 * The initial refcount is 1, and needs to be decremented to release the
 * resources of the kmod_module. Since libkmod keeps track of all
 * kmod_modules created, they are all released upon @ctx destruction too. Do
 * not unref @ctx before all the desired operations with the returned
 * kmod_module are done.
 *
 * Returns: 0 on success or < 0 otherwise. It fails if name is not a valid
 * module name or if memory allocation failed.
 */
KMOD_EXPORT int kmod_module_new_from_name(struct kmod_ctx *ctx,
                                                const char *name,
                                                struct kmod_module **mod)
{
        size_t namelen;
        char name_norm[PATH_MAX];

        if (ctx == NULL || name == NULL || mod == NULL)
                return -ENOENT;

        modname_normalize(name, name_norm, &namelen);

        return kmod_module_new(ctx, name_norm, name_norm, namelen, NULL, 0, mod);
}

int kmod_module_new_from_alias(struct kmod_ctx *ctx, const char *alias,
                                const char *name, struct kmod_module **mod)
{
        int err;
        char key[PATH_MAX];
        size_t namelen = strlen(name);
        size_t aliaslen = strlen(alias);

        if (namelen + aliaslen + 2 > PATH_MAX)
                return -ENAMETOOLONG;

        memcpy(key, name, namelen);
        memcpy(key + namelen + 1, alias, aliaslen + 1);
        key[namelen] = '\\';

        err = kmod_module_new(ctx, key, name, namelen, alias, aliaslen, mod);
        if (err < 0)
                return err;

        return 0;
}

/**
 * kmod_module_new_from_path:
 * @ctx: kmod library context
 * @path: path where to find the given module
 * @mod: where to save the created struct kmod_module
 *
 * Create a new struct kmod_module using the module path. @path must be an
 * existent file with in the filesystem and must be accessible to libkmod.
 *
 * The initial refcount is 1, and needs to be decremented to release the
 * resources of the kmod_module. Since libkmod keeps track of all
 * kmod_modules created, they are all released upon @ctx destruction too. Do
 * not unref @ctx before all the desired operations with the returned
 * kmod_module are done.
 *
 * If @path is relative, it's treated as relative to the current working
 * directory. Otherwise, give an absolute path.
 *
 * Returns: 0 on success or < 0 otherwise. It fails if file does not exist, if
 * it's not a valid file for a kmod_module or if memory allocation failed.
 */
KMOD_EXPORT int kmod_module_new_from_path(struct kmod_ctx *ctx,
                                                const char *path,
                                                struct kmod_module **mod)
{
        struct kmod_module *m;
        int err;
        struct stat st;
        char name[PATH_MAX];
        char *abspath;
        size_t namelen;

        if (ctx == NULL || path == NULL || mod == NULL)
                return -ENOENT;

        abspath = path_make_absolute_cwd(path);
        if (abspath == NULL) {
                DBG(ctx, "no absolute path for %s\n", path);
                return -ENOMEM;
        }

        err = stat(abspath, &st);
        if (err < 0) {
                err = -errno;
                DBG(ctx, "stat %s: %s\n", path, strerror(errno));
                free(abspath);
                return err;
        }

        if (path_to_modname(path, name, &namelen) == NULL) {
                DBG(ctx, "could not get modname from path %s\n", path);
                free(abspath);
                return -ENOENT;
        }

        m = kmod_pool_get_module(ctx, name);
        if (m != NULL) {
                if (m->path == NULL)
                        m->path = abspath;
                else if (streq(m->path, abspath))
                        free(abspath);
                else {
                        ERR(ctx, "kmod_module '%s' already exists with different path: new-path='%s' old-path='%s'\n",
                                                        name, abspath, m->path);
                        free(abspath);
                        return -EEXIST;
                }

                *mod = kmod_module_ref(m);
                return 0;
        }

        err = kmod_module_new(ctx, name, name, namelen, NULL, 0, &m);
        if (err < 0)
                return err;

        m->path = abspath;
        *mod = m;

        return 0;
}

/**
 * kmod_module_unref:
 * @mod: kmod module
 *
 * Drop a reference of the kmod module. If the refcount reaches zero, its
 * resources are released.
 *
 * Returns: NULL if @mod is NULL or if the module was released. Otherwise it
 * returns the passed @mod with its refcount decremented.
 */
KMOD_EXPORT struct kmod_module *kmod_module_unref(struct kmod_module *mod)
{
        if (mod == NULL)
                return NULL;

        if (--mod->refcount > 0)
                return mod;

        DBG(mod->ctx, "kmod_module %p released\n", mod);

        kmod_pool_del_module(mod->ctx, mod, mod->hashkey);
        kmod_module_unref_list(mod->dep);
        kmod_unref(mod->ctx);
        free(mod->options);
        free(mod->path);
        free(mod);
        return NULL;
}

/**
 * kmod_module_ref:
 * @mod: kmod module
 *
 * Take a reference of the kmod module, incrementing its refcount.
 *
 * Returns: the passed @module with its refcount incremented.
 */
KMOD_EXPORT struct kmod_module *kmod_module_ref(struct kmod_module *mod)
{
        if (mod == NULL)
                return NULL;

        mod->refcount++;

        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)

/**
 * kmod_module_new_from_lookup:
 * @ctx: kmod library context
 * @given_alias: alias to look for
 * @list: an empty list where to save the list of modules matching
 * @given_alias
 *
 * Create a new list of kmod modules using an alias or module name and lookup
 * libkmod's configuration files and indexes in order to find the module.
 * Once it's found in one of the places, it stops searching and create the
 * list of modules that is saved in @list.
 *
 * The search order is: 1. aliases in configuration file; 2. module names in
 * modules.dep index; 3. symbol aliases in modules.symbols index; 4. aliases
 * in modules.alias index.
 *
 * The initial refcount is 1, and needs to be decremented to release the
 * resources of the kmod_module. The returned @list must be released by
 * calling kmod_module_unref_list(). Since libkmod keeps track of all
 * kmod_modules created, they are all released upon @ctx destruction too. Do
 * not unref @ctx before all the desired operations with the returned list are
 * completed.
 *
 * Returns: 0 on success or < 0 otherwise. It fails if any of the lookup
 * methods failed, which is basically due to memory allocation fail. If module
 * is not found, it still returns 0, but @list is an empty list.
 */
KMOD_EXPORT int kmod_module_new_from_lookup(struct kmod_ctx *ctx,
                                                const char *given_alias,
                                                struct kmod_list **list)
{
        int err;
        char alias[PATH_MAX];

        if (ctx == NULL || given_alias == NULL)
                return -ENOENT;

        if (list == NULL || *list != NULL) {
                ERR(ctx, "An empty list is needed to create lookup\n");
                return -ENOSYS;
        }

        if (alias_normalize(given_alias, alias, NULL) < 0) {
                DBG(ctx, "invalid alias: %s\n", given_alias);
                return -EINVAL;
        }

        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);

        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);

finish:
        DBG(ctx, "lookup %s=%d, list=%p\n", alias, err, *list);
        return 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:
 * @list: list of kmod modules
 *
 * Drop a reference of each kmod module in @list and releases the resources
 * taken by the list itself.
 *
 * Returns: NULL if @mod is NULL or if the module was released. Otherwise it
 * returns the passed @mod with its refcount decremented.
 */
KMOD_EXPORT int kmod_module_unref_list(struct kmod_list *list)
{
        for (; list != NULL; list = kmod_list_remove(list))
                kmod_module_unref(list->data);

        return 0;
}

/**
 * kmod_module_get_filtered_blacklist:
 * @ctx: kmod library context
 * @input: list of kmod_module to be filtered with blacklist
 * @output: where to save the new list
 *
 * This function should not be used. Use kmod_module_apply_filter instead.
 *
 * Given a list @input, this function filter it out with config's blacklist
 * and save it in @output.
 *
 * Returns: 0 on success or < 0 otherwise. @output is saved with the updated
 * list.
 */
KMOD_EXPORT int kmod_module_get_filtered_blacklist(const struct kmod_ctx *ctx,
                                                const struct kmod_list *input,
                                                struct kmod_list **output)
{
        return kmod_module_apply_filter(ctx, KMOD_FILTER_BLACKLIST, input, output);
}

static const struct kmod_list *module_get_dependencies_noref(const struct kmod_module *mod)
{
        if (!mod->init.dep) {
                /* lazy init */
                char *line = kmod_search_moddep(mod->ctx, mod->name);

                if (line == NULL)
                        return NULL;

                kmod_module_parse_depline((struct kmod_module *)mod, line);
                free(line);

                if (!mod->init.dep)
                        return NULL;
        }

        return mod->dep;
}

/**
 * kmod_module_get_dependencies:
 * @mod: kmod module
 *
 * Search the modules.dep index to find the dependencies of the given @mod.
 * The result is cached in @mod, so subsequent calls to this function will
 * return the already searched list of modules.
 *
 * Returns: NULL on failure or if there are any dependencies. Otherwise it
 * returns a list of kmod modules that can be released by calling
 * kmod_module_unref_list().
 */
KMOD_EXPORT struct kmod_list *kmod_module_get_dependencies(const struct kmod_module *mod)
{
        struct kmod_list *l, *l_new, *list_new = NULL;

        if (mod == NULL)
                return NULL;

        module_get_dependencies_noref(mod);

        kmod_list_foreach(l, mod->dep) {
                l_new = kmod_list_append(list_new, kmod_module_ref(l->data));
                if (l_new == NULL) {
                        kmod_module_unref(l->data);
                        goto fail;
                }

                list_new = l_new;
        }

        return list_new;

fail:
        ERR(mod->ctx, "out of memory\n");
        kmod_module_unref_list(list_new);
        return NULL;
}

/**
 * kmod_module_get_module:
 * @entry: an entry in a list of kmod modules.
 *
 * Get the kmod module of this @entry in the list, increasing its refcount.
 * After it's used, unref it. Since the refcount is incremented upon return,
 * you still have to call kmod_module_unref_list() to release the list of kmod
 * modules.
 *
 * Returns: NULL on failure or the kmod_module contained in this list entry
 * with its refcount incremented.
 */
KMOD_EXPORT struct kmod_module *kmod_module_get_module(const struct kmod_list *entry)
{
        if (entry == NULL)
                return NULL;

        return kmod_module_ref(entry->data);
}

/**
 * kmod_module_get_name:
 * @mod: kmod module
 *
 * Get the name of this kmod module. Name is always available, independently
 * if it was created by kmod_module_new_from_name() or another function and
 * it's always normalized (dashes are replaced with underscores).
 *
 * Returns: the name of this kmod module.
 */
KMOD_EXPORT const char *kmod_module_get_name(const struct kmod_module *mod)
{
        if (mod == NULL)
                return NULL;

        return mod->name;
}

/**
 * kmod_module_get_path:
 * @mod: kmod module
 *
 * Get the path of this kmod module. If this kmod module was not created by
 * path, it can search the modules.dep index in order to find out the module
 * under context's dirname.
 *
 * Returns: the path of this kmod module or NULL if such information is not
 * available.
 */
KMOD_EXPORT const char *kmod_module_get_path(const struct kmod_module *mod)
{
        char *line;

        if (mod == NULL)
                return NULL;

        DBG(mod->ctx, "name='%s' path='%s'\n", mod->name, mod->path);

        if (mod->path != NULL)
                return mod->path;
        if (mod->init.dep)
                return NULL;

        /* lazy init */
        line = kmod_search_moddep(mod->ctx, mod->name);
        if (line == NULL)
                return NULL;

        kmod_module_parse_depline((struct kmod_module *) mod, line);
        free(line);

        return mod->path;
}


extern long delete_module(const char *name, unsigned int flags);

/**
 * kmod_module_remove_module:
 * @mod: kmod module
 * @flags: flags to pass to Linux kernel when removing the module
 *
 * Remove a module from Linux kernel.
 *
 * Returns: 0 on success or < 0 on failure.
 */
KMOD_EXPORT int kmod_module_remove_module(struct kmod_module *mod,
                                                        unsigned int flags)
{
        int err;

        if (mod == NULL)
                return -ENOENT;

        /* Filter out other flags */
        flags &= (KMOD_REMOVE_FORCE | KMOD_REMOVE_NOWAIT);

        err = delete_module(mod->name, flags);
        if (err != 0) {
                err = -errno;
                ERR(mod->ctx, "could not remove '%s': %m\n", mod->name);
        }

        return err;
}

extern long init_module(const void *mem, unsigned long len, const char *args);

/**
 * kmod_module_insert_module:
 * @mod: kmod module
 * @flags: flags are not passed to Linux Kernel, but instead they dictate the
 * behavior of this function.
 * @options: module's options to pass to Linux Kernel.
 *
 * Insert a module in Linux kernel. It opens the file pointed by @mod,
 * mmap'ing it and passing to kernel.
 *
 * Returns: 0 on success or < 0 on failure. If module is already loaded it
 * returns -EEXIST.
 */
KMOD_EXPORT int kmod_module_insert_module(struct kmod_module *mod,
                                                        unsigned int flags,
                                                        const char *options)
{
        int err;
        const void *mem;
        off_t size;
        struct kmod_file *file;
        struct kmod_elf *elf = NULL;
        const char *path;
        const char *args = options ? options : "";

        if (mod == NULL)
                return -ENOENT;

        path = kmod_module_get_path(mod);
        if (path == NULL) {
                ERR(mod->ctx, "could not find module by name='%s'\n", mod->name);
                return -ENOSYS;
        }

        file = kmod_file_open(mod->ctx, path);
        if (file == NULL) {
                err = -errno;
                return err;
        }

        size = kmod_file_get_size(file);
        mem = kmod_file_get_contents(file);

        if (flags & (KMOD_INSERT_FORCE_VERMAGIC | KMOD_INSERT_FORCE_MODVERSION)) {
                elf = kmod_elf_new(mem, size);
                if (elf == NULL) {
                        err = -errno;
                        goto elf_failed;
                }

                if (flags & KMOD_INSERT_FORCE_MODVERSION) {
                        err = kmod_elf_strip_section(elf, "__versions");
                        if (err < 0)
                                INFO(mod->ctx, "Failed to strip modversion: %s\n", strerror(-err));
                }

                if (flags & KMOD_INSERT_FORCE_VERMAGIC) {
                        err = kmod_elf_strip_vermagic(elf);
                        if (err < 0)
                                INFO(mod->ctx, "Failed to strip vermagic: %s\n", strerror(-err));
                }

                mem = kmod_elf_get_memory(elf);
        }

        err = init_module(mem, size, args);
        if (err < 0) {
                err = -errno;
                INFO(mod->ctx, "Failed to insert module '%s': %m\n", path);
        }

        if (elf != NULL)
                kmod_elf_unref(elf);
elf_failed:
        kmod_file_unref(file);

        return err;
}

static bool module_is_blacklisted(struct kmod_module *mod)
{
        struct kmod_ctx *ctx = mod->ctx;
        const struct kmod_config *config = kmod_get_config(ctx);
        const struct kmod_list *bl = config->blacklists;
        const struct kmod_list *l;

        kmod_list_foreach(l, bl) {
                const char *modname = kmod_blacklist_get_modname(l);

                if (streq(modname, mod->name))
                        return true;
        }

        return false;
}

/**
 * kmod_module_apply_filter
 * @ctx: kmod library context
 * @filter_type: bitmask to filter modules on
 * @input: list of kmod_module to be filtered
 * @output: where to save the new list
 *
 * Given a list @input, this function filter it out by the filter mask
 * and save it in @output.
 *
 * Returns: 0 on success or < 0 otherwise. @output is saved with the updated
 * list.
 */
KMOD_EXPORT int kmod_module_apply_filter(const struct kmod_ctx *ctx,
                                                enum kmod_filter filter_type,
                                                const struct kmod_list *input,
                                                struct kmod_list **output)
{
        const struct kmod_list *li;

        if (ctx == NULL || output == NULL)
                return -ENOENT;

        *output = NULL;
        if (input == NULL)
                return 0;

        kmod_list_foreach(li, input) {
                struct kmod_module *mod = li->data;
                struct kmod_list *node;

                if ((filter_type & KMOD_FILTER_BLACKLIST) &&
                                module_is_blacklisted(mod))
                        continue;

                if ((filter_type & KMOD_FILTER_BUILTIN) && mod->builtin)
                        continue;

                node = kmod_list_append(*output, mod);
                if (node == NULL)
                        goto fail;

                *output = node;
                kmod_module_ref(mod);
        }

        return 0;

fail:
        kmod_module_unref_list(*output);
        *output = NULL;
        return -ENOMEM;
}

static int command_do(struct kmod_module *mod, const char *type,
                                                        const char *cmd)
{
        const char *modname = kmod_module_get_name(mod);
        int err;

        DBG(mod->ctx, "%s %s\n", type, cmd);

        setenv("MODPROBE_MODULE", modname, 1);
        err = system(cmd);
        unsetenv("MODPROBE_MODULE");

        if (err == -1 || WEXITSTATUS(err)) {
                ERR(mod->ctx, "Error running %s command for %s\n",
                                                                type, modname);
                if (err != -1)
                        err = -WEXITSTATUS(err);
        }

        return err;
}

struct probe_insert_cb {
        int (*run_install)(struct kmod_module *m, const char *cmd, void *data);
        void *data;
};

static int module_do_install_commands(struct kmod_module *mod,
                                        const char *options,
                                        struct probe_insert_cb *cb)
{
        const char *command = kmod_module_get_install_commands(mod);
        char *p, *cmd;
        int err;
        size_t cmdlen, options_len, varlen;

        assert(command);

        if (options == NULL)
                options = "";

        options_len = strlen(options);
        cmdlen = strlen(command);
        varlen = sizeof("$CMDLINE_OPTS") - 1;

        cmd = memdup(command, cmdlen + 1);
        if (cmd == NULL)
                return -ENOMEM;

        while ((p = strstr(cmd, "$CMDLINE_OPTS")) != NULL) {
                size_t prefixlen = p - cmd;
                size_t suffixlen = cmdlen - prefixlen - varlen;
                size_t slen = cmdlen - varlen + options_len;
                char *suffix = p + varlen;
                char *s = malloc(slen + 1);
                if (s == NULL) {
                        free(cmd);
                        return -ENOMEM;
                }
                memcpy(s, cmd, p - cmd);
                memcpy(s + prefixlen, options, options_len);
                memcpy(s + prefixlen + options_len, suffix, suffixlen);
                s[slen] = '\0';

                free(cmd);
                cmd = s;
                cmdlen = slen;
        }

        if (cb->run_install != NULL)
                err = cb->run_install(mod, cmd, cb->data);
        else
                err = command_do(mod, "install", cmd);

        free(cmd);

        return err;
}

static char *module_options_concat(const char *opt, const char *xopt)
{
        // TODO: we might need to check if xopt overrides options on opt
        size_t optlen = opt == NULL ? 0 : strlen(opt);
        size_t xoptlen = xopt == NULL ? 0 : strlen(xopt);
        char *r;

        if (optlen == 0 && xoptlen == 0)
                return NULL;

        r = malloc(optlen + xoptlen + 2);

        if (opt != NULL) {
                memcpy(r, opt, optlen);
                r[optlen] = ' ';
                optlen++;
        }

        if (xopt != NULL)
                memcpy(r + optlen, xopt, xoptlen);

        r[optlen + xoptlen] = '\0';

        return r;
}

static int __kmod_module_get_probe_list(struct kmod_module *mod,
                                                bool ignorecmd,
                                                struct kmod_list **list);

/* re-entrant */
static int __kmod_module_fill_softdep(struct kmod_module *mod,
                                                struct kmod_list **list)
{
        struct kmod_list *pre = NULL, *post = NULL, *l;
        int err;

        err = kmod_module_get_softdeps(mod, &pre, &post);
        if (err < 0) {
                ERR(mod->ctx, "could not get softdep: %s\n",
                                                        strerror(-err));
                goto fail;
        }

        kmod_list_foreach(l, pre) {
                struct kmod_module *m = l->data;
                err = __kmod_module_get_probe_list(m, false, list);
                if (err < 0)
                        goto fail;
        }

        l = kmod_list_append(*list, kmod_module_ref(mod));
        if (l == NULL) {
                kmod_module_unref(mod);
                err = -ENOMEM;
                goto fail;
        }
        *list = l;
        mod->ignorecmd = (pre != NULL || post != NULL);

        kmod_list_foreach(l, post) {
                struct kmod_module *m = l->data;
                err = __kmod_module_get_probe_list(m, false, list);
                if (err < 0)
                        goto fail;
        }

fail:
        kmod_module_unref_list(pre);
        kmod_module_unref_list(post);

        return err;
}

/* re-entrant */
static int __kmod_module_get_probe_list(struct kmod_module *mod,
                                                bool ignorecmd,
                                                struct kmod_list **list)
{
        struct kmod_list *dep, *l;
        int err = 0;

        if (mod->visited) {
                DBG(mod->ctx, "Ignore module '%s': already visited\n",
                                                                mod->name);
                return 0;
        }
        mod->visited = true;

        dep = kmod_module_get_dependencies(mod);
        kmod_list_foreach(l, dep) {
                struct kmod_module *m = l->data;
                err = __kmod_module_fill_softdep(m, list);
                if (err < 0)
                        goto finish;
        }

        if (ignorecmd) {
                l = kmod_list_append(*list, kmod_module_ref(mod));
                if (l == NULL) {
                        kmod_module_unref(mod);
                        err = -ENOMEM;
                        goto finish;
                }
                *list = l;
                mod->ignorecmd = true;
        } else
                err = __kmod_module_fill_softdep(mod, list);

finish:
        kmod_module_unref_list(dep);
        return err;
}

static int kmod_module_get_probe_list(struct kmod_module *mod,
                                                bool ignorecmd,
                                                struct kmod_list **list)
{
        int err;

        assert(mod != NULL);
        assert(list != NULL && *list == NULL);

        /*
         * Make sure we don't get screwed by previous calls to this function
         */
        kmod_set_modules_visited(mod->ctx, false);

        err = __kmod_module_get_probe_list(mod, ignorecmd, list);
        if (err < 0) {
                kmod_module_unref_list(*list);
                *list = NULL;
        }

        return err;
}

/**
 * kmod_module_probe_insert_module:
 * @mod: kmod module
 * @flags: flags are not passed to Linux Kernel, but instead they dictate the
 * behavior of this function.
 * @extra_options: module's options to pass to Linux Kernel. It applies only
 * to @mod, not to its dependencies.
 * @run_install: function to run when @mod is backed by an install command.
 * @data: data to give back to @run_install callback
 * @print_action: function to call with the action being taken (install or
 * insmod). It's useful for tools like modprobe when running with verbose
 * output or in dry-run mode.
 *
 * Insert a module in Linux kernel resolving dependencies, soft dependencies,
 * install commands and applying blacklist.
 *
 * If @run_install is NULL, this function will fork and exec by calling
 * system(3). Don't pass a NULL argument in @run_install if your binary is
 * setuid/setgid (see warning in system(3)). If you need control over the
 * execution of an install command, give a callback function instead.
 *
 * Returns: 0 on success, > 0 if stopped by a reason given in @flags or < 0 on
 * failure.
 */
KMOD_EXPORT int kmod_module_probe_insert_module(struct kmod_module *mod,
                        unsigned int flags, const char *extra_options,
                        int (*run_install)(struct kmod_module *m,
                                                const char *cmd, void *data),
                        const void *data,
                        void (*print_action)(struct kmod_module *m,
                                                bool install,
                                                const char *options))
{
        struct kmod_list *list = NULL, *l;
        struct probe_insert_cb cb;
        int err;

        if (mod == NULL)
                return -ENOENT;

        if (!(flags & KMOD_PROBE_IGNORE_LOADED)
                                        && module_is_inkernel(mod)) {
                if (flags & KMOD_PROBE_FAIL_ON_LOADED)
                        return -EEXIST;
                else
                        return 0;
        }

        err = flags & (KMOD_PROBE_APPLY_BLACKLIST |
                                        KMOD_PROBE_APPLY_BLACKLIST_ALL);
        if (err != 0) {
                if (module_is_blacklisted(mod))
                        return err;
        }

        err = kmod_module_get_probe_list(mod,
                                !!(flags & KMOD_PROBE_IGNORE_COMMAND), &list);
        if (err < 0)
                return err;

        if (flags & KMOD_PROBE_APPLY_BLACKLIST_ALL) {
                struct kmod_list *filtered = NULL;

                err = kmod_module_apply_filter(mod->ctx,
                                KMOD_FILTER_BLACKLIST, list, &filtered);
                if (err < 0)
                        return err;

                kmod_module_unref_list(list);
                if (filtered == NULL)
                        return KMOD_PROBE_APPLY_BLACKLIST_ALL;

                list = filtered;
        }

        cb.run_install = run_install;
        cb.data = (void *) data;

        kmod_list_foreach(l, list) {
                struct kmod_module *m = l->data;
                const char *moptions = kmod_module_get_options(m);
                const char *cmd = kmod_module_get_install_commands(m);
                char *options;

                if (!(flags & KMOD_PROBE_IGNORE_LOADED)
                                                && module_is_inkernel(m)) {
                        DBG(mod->ctx, "Ignoring module '%s': already loaded\n",
                                                                m->name);
                        err = -EEXIST;
                        goto finish_module;
                }

                options = module_options_concat(moptions,
                                        m == mod ? extra_options : NULL);

                if (cmd != NULL && !m->ignorecmd) {
                        if (print_action != NULL)
                                print_action(m, true, options ?: "");

                        if (!(flags & KMOD_PROBE_DRY_RUN))
                                err = module_do_install_commands(m, options,
                                                                        &cb);
                } else {
                        if (print_action != NULL)
                                print_action(m, false, options ?: "");

                        if (!(flags & KMOD_PROBE_DRY_RUN))
                                err = kmod_module_insert_module(m, flags,
                                                                options);
                }

                free(options);

finish_module:
                /*
                 * Treat "already loaded" error. If we were told to stop on
                 * already loaded and the module being loaded is not a softdep
                 * or dep, bail out. Otherwise, just ignore and continue.
                 *
                 * We need to check here because of race conditions. We
                 * checked first if module was already loaded but it may have
                 * been loaded between the check and the moment we try to
                 * insert it.
                 */
                if (err == -EEXIST && m == mod &&
                                (flags & KMOD_PROBE_FAIL_ON_LOADED))
                        break;

                if (err == -EEXIST)
                        err = 0;
                else if (err < 0)
                        break;
        }

        kmod_module_unref_list(list);
        return err;
}

/**
 * kmod_module_get_options:
 * @mod: kmod module
 *
 * Get options of this kmod module. Options come from the configuration file
 * and are cached in @mod. The first call to this function will search for
 * this module in configuration and subsequent calls return the cached string.
 *
 * Returns: a string with all the options separated by spaces. This string is
 * owned by @mod, do not free it.
 */
KMOD_EXPORT const char *kmod_module_get_options(const struct kmod_module *mod)
{
        if (mod == NULL)
                return NULL;

        if (!mod->init.options) {
                /* lazy init */
                struct kmod_module *m = (struct kmod_module *)mod;
                const struct kmod_list *l;
                const struct kmod_config *config;
                char *opts = NULL;
                size_t optslen = 0;

                config = kmod_get_config(mod->ctx);

                kmod_list_foreach(l, config->options) {
                        const char *modname = kmod_option_get_modname(l);
                        const char *str;
                        size_t len;
                        void *tmp;

                        DBG(mod->ctx, "modname=%s mod->name=%s mod->alias=%s\n", modname, mod->name, mod->alias);
                        if (!(streq(modname, mod->name) || (mod->alias != NULL &&
                                                streq(modname, mod->alias))))
                                continue;

                        DBG(mod->ctx, "passed = modname=%s mod->name=%s mod->alias=%s\n", modname, mod->name, mod->alias);
                        str = kmod_option_get_options(l);
                        len = strlen(str);
                        if (len < 1)
                                continue;

                        tmp = realloc(opts, optslen + len + 2);
                        if (tmp == NULL) {
                                free(opts);
                                goto failed;
                        }

                        opts = tmp;

                        if (optslen > 0) {
                                opts[optslen] = ' ';
                                optslen++;
                        }

                        memcpy(opts + optslen, str, len);
                        optslen += len;
                        opts[optslen] = '\0';
                }

                m->init.options = true;
                m->options = opts;
        }

        return mod->options;

failed:
        ERR(mod->ctx, "out of memory\n");
        return NULL;
}

/**
 * kmod_module_get_install_commands:
 * @mod: kmod module
 *
 * Get install commands for this kmod module. Install commands come from the
 * configuration file and are cached in @mod. The first call to this function
 * will search for this module in configuration and subsequent calls return
 * the cached string. The install commands are returned as they were in the
 * configuration, concatenated by ';'. No other processing is made in this
 * string.
 *
 * Returns: a string with all install commands separated by semicolons. This
 * string is owned by @mod, do not free it.
 */
KMOD_EXPORT const char *kmod_module_get_install_commands(const struct kmod_module *mod)
{
        if (mod == NULL)
                return NULL;

        if (!mod->init.install_commands) {
                /* lazy init */
                struct kmod_module *m = (struct kmod_module *)mod;
                const struct kmod_list *l;
                const struct kmod_config *config;

                config = kmod_get_config(mod->ctx);

                kmod_list_foreach(l, config->install_commands) {
                        const char *modname = kmod_command_get_modname(l);

                        if (fnmatch(modname, mod->name, 0) != 0)
                                continue;

                        m->install_commands = kmod_command_get_command(l);

                        /*
                         * find only the first command, as modprobe from
                         * module-init-tools does
                         */
                        break;
                }

                m->init.install_commands = true;
        }

        return mod->install_commands;
}

void kmod_module_set_install_commands(struct kmod_module *mod, const char *cmd)
{
        mod->init.install_commands = true;
        mod->install_commands = cmd;
}

static struct kmod_list *lookup_softdep(struct kmod_ctx *ctx, const char * const * array, unsigned int count)
{
        struct kmod_list *ret = NULL;
        unsigned i;

        for (i = 0; i < count; i++) {
                const char *depname = array[i];
                struct kmod_list *lst = NULL;
                int err;

                err = kmod_module_new_from_lookup(ctx, depname, &lst);
                if (err < 0) {
                        ERR(ctx, "failed to lookup soft dependency '%s', continuing anyway.\n", depname);
                        continue;
                } else if (lst != NULL)
                        ret = kmod_list_append_list(ret, lst);
        }
        return ret;
}

/**
 * kmod_module_get_softdeps:
 * @mod: kmod module
 * @pre: where to save the list of preceding soft dependencies.
 * @post: where to save the list of post soft dependencies.
 *
 * Get soft dependencies for this kmod module. Soft dependencies come
 * from configuration file and are not cached in @mod because it may include
 * dependency cycles that would make we leak kmod_module. Any call
 * to this function will search for this module in configuration, allocate a
 * list and return the result.
 *
 * Both @pre and @post are newly created list of kmod_module and
 * should be unreferenced with kmod_module_unref_list().
 *
 * Returns: 0 on success or < 0 otherwise.
 */
KMOD_EXPORT int kmod_module_get_softdeps(const struct kmod_module *mod,
                                                struct kmod_list **pre,
                                                struct kmod_list **post)
{
        const struct kmod_list *l;
        const struct kmod_config *config;

        if (mod == NULL || pre == NULL || post == NULL)
                return -ENOENT;

        assert(*pre == NULL);
        assert(*post == NULL);

        config = kmod_get_config(mod->ctx);

        kmod_list_foreach(l, config->softdeps) {
                const char *modname = kmod_softdep_get_name(l);
                const char * const *array;
                unsigned count;

                if (fnmatch(modname, mod->name, 0) != 0)
                        continue;

                array = kmod_softdep_get_pre(l, &count);
                *pre = lookup_softdep(mod->ctx, array, count);
                array = kmod_softdep_get_post(l, &count);
                *post = lookup_softdep(mod->ctx, array, count);

                /*
                 * find only the first command, as modprobe from
                 * module-init-tools does
                 */
                break;
        }

        return 0;
}

/**
 * kmod_module_get_remove_commands:
 * @mod: kmod module
 *
 * Get remove commands for this kmod module. Remove commands come from the
 * configuration file and are cached in @mod. The first call to this function
 * will search for this module in configuration and subsequent calls return
 * the cached string. The remove commands are returned as they were in the
 * configuration, concatenated by ';'. No other processing is made in this
 * string.
 *
 * Returns: a string with all remove commands separated by semicolons. This
 * string is owned by @mod, do not free it.
 */
KMOD_EXPORT const char *kmod_module_get_remove_commands(const struct kmod_module *mod)
{
        if (mod == NULL)
                return NULL;

        if (!mod->init.remove_commands) {
                /* lazy init */
                struct kmod_module *m = (struct kmod_module *)mod;
                const struct kmod_list *l;
                const struct kmod_config *config;

                config = kmod_get_config(mod->ctx);

                kmod_list_foreach(l, config->remove_commands) {
                        const char *modname = kmod_command_get_modname(l);

                        if (fnmatch(modname, mod->name, 0) != 0)
                                continue;

                        m->remove_commands = kmod_command_get_command(l);

                        /*
                         * find only the first command, as modprobe from
                         * module-init-tools does
                         */
                        break;
                }

                m->init.remove_commands = true;
        }

        return mod->remove_commands;
}

void kmod_module_set_remove_commands(struct kmod_module *mod, const char *cmd)
{
        mod->init.remove_commands = true;
        mod->remove_commands = cmd;
}

/**
 * SECTION:libkmod-loaded
 * @short_description: currently loaded modules
 *
 * Information about currently loaded modules, as reported by Linux kernel.
 * These information are not cached by libkmod and are always read from /sys
 * and /proc/modules.
 */

/**
 * kmod_module_new_from_loaded:
 * @ctx: kmod library context
 * @list: where to save the list of loaded modules
 *
 * Create a new list of kmod modules with all modules currently loaded in
 * kernel. It uses /proc/modules to get the names of loaded modules and to
 * create kmod modules by calling kmod_module_new_from_name() in each of them.
 * They are put are put in @list in no particular order.
 *
 * The initial refcount is 1, and needs to be decremented to release the
 * resources of the kmod_module. The returned @list must be released by
 * calling kmod_module_unref_list(). Since libkmod keeps track of all
 * kmod_modules created, they are all released upon @ctx destruction too. Do
 * not unref @ctx before all the desired operations with the returned list are
 * completed.
 *
 * Returns: 0 on success or < 0 on error.
 */
KMOD_EXPORT int kmod_module_new_from_loaded(struct kmod_ctx *ctx,
                                                struct kmod_list **list)
{
        struct kmod_list *l = NULL;
        FILE *fp;
        char line[4096];

        if (ctx == NULL || list == NULL)
                return -ENOENT;

        fp = fopen("/proc/modules", "re");
        if (fp == NULL) {
                int err = -errno;
                ERR(ctx, "could not open /proc/modules: %s\n", strerror(errno));
                return err;
        }

        while (fgets(line, sizeof(line), fp)) {
                struct kmod_module *m;
                struct kmod_list *node;
                int err;
                char *saveptr, *name = strtok_r(line, " \t", &saveptr);

                err = kmod_module_new_from_name(ctx, name, &m);
                if (err < 0) {
                        ERR(ctx, "could not get module from name '%s': %s\n",
                                name, strerror(-err));
                        continue;
                }

                node = kmod_list_append(l, m);
                if (node)
                        l = node;
                else {
                        ERR(ctx, "out of memory\n");
                        kmod_module_unref(m);
                }
        }

        fclose(fp);
        *list = l;

        return 0;
}

/**
 * kmod_module_initstate_str:
 * @state: the state as returned by kmod_module_get_initstate()
 *
 * Translate a initstate to a string.
 *
 * Returns: the string associated to the @state. This string is statically
 * allocated, do not free it.
 */
KMOD_EXPORT const char *kmod_module_initstate_str(enum kmod_module_initstate state)
{
        switch (state) {
        case KMOD_MODULE_BUILTIN:
                return "builtin";
        case KMOD_MODULE_LIVE:
                return "live";
        case KMOD_MODULE_COMING:
                return "coming";
        case KMOD_MODULE_GOING:
                return "going";
        default:
                return NULL;
        }
}

/**
 * kmod_module_get_initstate:
 * @mod: kmod module
 *
 * Get the initstate of this @mod, as returned by Linux Kernel, by reading
 * /sys filesystem.
 *
 * Returns: < 0 on error or enum kmod_initstate if module is found in kernel.
 */
KMOD_EXPORT int kmod_module_get_initstate(const struct kmod_module *mod)
{
        char path[PATH_MAX], buf[32];
        int fd, err, pathlen;

        if (mod == NULL)
                return -ENOENT;

        if (mod->builtin)
                return KMOD_MODULE_BUILTIN;

        pathlen = snprintf(path, sizeof(path),
                                "/sys/module/%s/initstate", mod->name);
        fd = open(path, O_RDONLY|O_CLOEXEC);
        if (fd < 0) {
                err = -errno;

                DBG(mod->ctx, "could not open '%s': %s\n",
                        path, strerror(-err));

                if (pathlen > (int)sizeof("/initstate") - 1) {
                        struct stat st;
                        path[pathlen - (sizeof("/initstate") - 1)] = '\0';
                        if (stat(path, &st) == 0 && S_ISDIR(st.st_mode))
                                return KMOD_MODULE_BUILTIN;
                }

                DBG(mod->ctx, "could not open '%s': %s\n",
                        path, strerror(-err));
                return err;
        }

        err = read_str_safe(fd, buf, sizeof(buf));
        close(fd);
        if (err < 0) {
                ERR(mod->ctx, "could not read from '%s': %s\n",
                        path, strerror(-err));
                return err;
        }

        if (streq(buf, "live\n"))
                return KMOD_MODULE_LIVE;
        else if (streq(buf, "coming\n"))
                return KMOD_MODULE_COMING;
        else if (streq(buf, "going\n"))
                return KMOD_MODULE_GOING;

        ERR(mod->ctx, "unknown %s: '%s'\n", path, buf);
        return -EINVAL;
}

/**
 * kmod_module_get_size:
 * @mod: kmod module
 *
 * Get the size of this kmod module as returned by Linux kernel. It reads the
 * file /proc/modules to search for this module and get its size.
 *
 * Returns: the size of this kmod module.
 */
KMOD_EXPORT long kmod_module_get_size(const struct kmod_module *mod)
{
        // FIXME TODO: this should be available from /sys/module/foo
        FILE *fp;
        char line[4096];
        int lineno = 0;
        long size = -ENOENT;

        if (mod == NULL)
                return -ENOENT;

        fp = fopen("/proc/modules", "re");
        if (fp == NULL) {
                int err = -errno;
                ERR(mod->ctx,
                    "could not open /proc/modules: %s\n", strerror(errno));
                return err;
        }

        while (fgets(line, sizeof(line), fp)) {
                char *saveptr, *endptr, *tok = strtok_r(line, " \t", &saveptr);
                long value;

                lineno++;
                if (tok == NULL || !streq(tok, mod->name))
                        continue;

                tok = strtok_r(NULL, " \t", &saveptr);
                if (tok == NULL) {
                        ERR(mod->ctx,
                        "invalid line format at /proc/modules:%d\n", lineno);
                        break;
                }

                value = strtol(tok, &endptr, 10);
                if (endptr == tok || *endptr != '\0') {
                        ERR(mod->ctx,
                        "invalid line format at /proc/modules:%d\n", lineno);
                        break;
                }

                size = value;
                break;
        }
        fclose(fp);
        return size;
}

/**
 * kmod_module_get_refcnt:
 * @mod: kmod module
 *
 * Get the ref count of this @mod, as returned by Linux Kernel, by reading
 * /sys filesystem.
 *
 * Returns: 0 on success or < 0 on failure.
 */
KMOD_EXPORT int kmod_module_get_refcnt(const struct kmod_module *mod)
{
        char path[PATH_MAX];
        long refcnt;
        int fd, err;

        if (mod == NULL)
                return -ENOENT;

        snprintf(path, sizeof(path), "/sys/module/%s/refcnt", mod->name);
        fd = open(path, O_RDONLY|O_CLOEXEC);
        if (fd < 0) {
                err = -errno;
                DBG(mod->ctx, "could not open '%s': %s\n",
                        path, strerror(errno));
                return err;
        }

        err = read_str_long(fd, &refcnt, 10);
        close(fd);
        if (err < 0) {
                ERR(mod->ctx, "could not read integer from '%s': '%s'\n",
                        path, strerror(-err));
                return err;
        }

        return (int)refcnt;
}

/**
 * kmod_module_get_holders:
 * @mod: kmod module
 *
 * Get a list of kmod modules that are holding this @mod, as returned by Linux
 * Kernel. After use, free the @list by calling kmod_module_unref_list().
 *
 * Returns: a new list of kmod modules on success or NULL on failure.
 */
KMOD_EXPORT struct kmod_list *kmod_module_get_holders(const struct kmod_module *mod)
{
        char dname[PATH_MAX];
        struct kmod_list *list = NULL;
        DIR *d;

        if (mod == NULL)
                return NULL;

        snprintf(dname, sizeof(dname), "/sys/module/%s/holders", mod->name);

        d = opendir(dname);
        if (d == NULL) {
                ERR(mod->ctx, "could not open '%s': %s\n",
                                                dname, strerror(errno));
                return NULL;
        }

        for (;;) {
                struct dirent de, *entp;
                struct kmod_module *holder;
                struct kmod_list *l;
                int err;

                err = readdir_r(d, &de, &entp);
                if (err != 0) {
                        ERR(mod->ctx, "could not iterate for module '%s': %s\n",
                                                mod->name, strerror(-err));
                        goto fail;
                }

                if (entp == NULL)
                        break;

                if (de.d_name[0] == '.') {
                        if (de.d_name[1] == '\0' ||
                            (de.d_name[1] == '.' && de.d_name[2] == '\0'))
                                continue;
                }

                err = kmod_module_new_from_name(mod->ctx, de.d_name, &holder);
                if (err < 0) {
                        ERR(mod->ctx, "could not create module for '%s': %s\n",
                                de.d_name, strerror(-err));
                        goto fail;
                }

                l = kmod_list_append(list, holder);
                if (l != NULL) {
                        list = l;
                } else {
                        ERR(mod->ctx, "out of memory\n");
                        kmod_module_unref(holder);
                        goto fail;
                }
        }

        closedir(d);
        return list;

fail:
        closedir(d);
        kmod_module_unref_list(list);
        return NULL;
}

struct kmod_module_section {
        unsigned long address;
        char name[];
};

static void kmod_module_section_free(struct kmod_module_section *section)
{
        free(section);
}

/**
 * kmod_module_get_sections:
 * @mod: kmod module
 *
 * Get a list of kmod sections of this @mod, as returned by Linux Kernel. The
 * structure contained in this list is internal to libkmod and their fields
 * can be obtained by calling kmod_module_section_get_name() and
 * kmod_module_section_get_address().
 *
 * After use, free the @list by calling kmod_module_section_free_list().
 *
 * Returns: a new list of kmod module sections on success or NULL on failure.
 */
KMOD_EXPORT struct kmod_list *kmod_module_get_sections(const struct kmod_module *mod)
{
        char dname[PATH_MAX];
        struct kmod_list *list = NULL;
        DIR *d;
        int dfd;

        if (mod == NULL)
                return NULL;

        snprintf(dname, sizeof(dname), "/sys/module/%s/sections", mod->name);

        d = opendir(dname);
        if (d == NULL) {
                ERR(mod->ctx, "could not open '%s': %s\n",
                        dname, strerror(errno));
                return NULL;
        }

        dfd = dirfd(d);

        for (;;) {
                struct dirent de, *entp;
                struct kmod_module_section *section;
                struct kmod_list *l;
                unsigned long address;
                size_t namesz;
                int fd, err;

                err = readdir_r(d, &de, &entp);
                if (err != 0) {
                        ERR(mod->ctx, "could not iterate for module '%s': %s\n",
                                                mod->name, strerror(-err));
                        goto fail;
                }

                if (de.d_name[0] == '.') {
                        if (de.d_name[1] == '\0' ||
                            (de.d_name[1] == '.' && de.d_name[2] == '\0'))
                                continue;
                }

                fd = openat(dfd, de.d_name, O_RDONLY|O_CLOEXEC);
                if (fd < 0) {
                        ERR(mod->ctx, "could not open '%s/%s': %m\n",
                                                        dname, de.d_name);
                        goto fail;
                }

                err = read_str_ulong(fd, &address, 16);
                close(fd);
                if (err < 0) {
                        ERR(mod->ctx, "could not read long from '%s/%s': %m\n",
                                                        dname, de.d_name);
                        goto fail;
                }

                namesz = strlen(de.d_name) + 1;
                section = malloc(sizeof(*section) + namesz);

                if (section == NULL) {
                        ERR(mod->ctx, "out of memory\n");
                        goto fail;
                }

                section->address = address;
                memcpy(section->name, de.d_name, namesz);

                l = kmod_list_append(list, section);
                if (l != NULL) {
                        list = l;
                } else {
                        ERR(mod->ctx, "out of memory\n");
                        free(section);
                        goto fail;
                }
        }

        closedir(d);
        return list;

fail:
        closedir(d);
        kmod_module_unref_list(list);
        return NULL;
}

/**
 * kmod_module_section_get_module_name:
 * @entry: a list entry representing a kmod module section
 *
 * Get the name of a kmod module section.
 *
 * After use, free the @list by calling kmod_module_section_free_list().
 *
 * Returns: the name of this kmod module section on success or NULL on
 * failure. The string is owned by the section, do not free it.
 */
KMOD_EXPORT const char *kmod_module_section_get_name(const struct kmod_list *entry)
{
        struct kmod_module_section *section;

        if (entry == NULL)
                return NULL;

        section = entry->data;
        return section->name;
}

/**
 * kmod_module_section_get_address:
 * @entry: a list entry representing a kmod module section
 *
 * Get the address of a kmod module section.
 *
 * After use, free the @list by calling kmod_module_section_free_list().
 *
 * Returns: the address of this kmod module section on success or ULONG_MAX
 * on failure.
 */
KMOD_EXPORT unsigned long kmod_module_section_get_address(const struct kmod_list *entry)
{
        struct kmod_module_section *section;

        if (entry == NULL)
                return (unsigned long)-1;

        section = entry->data;
        return section->address;
}

/**
 * kmod_module_section_free_list:
 * @list: kmod module section list
 *
 * Release the resources taken by @list
 */
KMOD_EXPORT void kmod_module_section_free_list(struct kmod_list *list)
{
        while (list) {
                kmod_module_section_free(list->data);
                list = kmod_list_remove(list);
        }
}

struct kmod_module_info {
        char *key;
        char value[];
};

static struct kmod_module_info *kmod_module_info_new(const char *key, size_t keylen, const char *value, size_t valuelen)
{
        struct kmod_module_info *info;

        info = malloc(sizeof(struct kmod_module_info) + keylen + valuelen + 2);
        if (info == NULL)
                return NULL;

        info->key = (char *)info + sizeof(struct kmod_module_info)
                + valuelen + 1;
        memcpy(info->key, key, keylen);
        info->key[keylen] = '\0';
        memcpy(info->value, value, valuelen);
        info->value[valuelen] = '\0';
        return info;
}

static void kmod_module_info_free(struct kmod_module_info *info)
{
        free(info);
}

/**
 * kmod_module_get_info:
 * @mod: kmod module
 * @list: where to return list of module information. Use
 *        kmod_module_info_get_key() and
 *        kmod_module_info_get_value(). Release this list with
 *        kmod_module_info_free_list()
 *
 * Get a list of entries in ELF section ".modinfo", these contain
 * alias, license, depends, vermagic and other keys with respective
 * values.
 *
 * After use, free the @list by calling kmod_module_info_free_list().
 *
 * Returns: 0 on success or < 0 otherwise.
 */
KMOD_EXPORT int kmod_module_get_info(const struct kmod_module *mod, struct kmod_list **list)
{
        struct kmod_file *file;
        struct kmod_elf *elf;
        const char *path;
        const void *mem;
        char **strings;
        size_t size;
        int i, count, ret = 0;

        if (mod == NULL || list == NULL)
                return -ENOENT;

        assert(*list == NULL);

        path = kmod_module_get_path(mod);
        if (path == NULL)
                return -ENOENT;

        file = kmod_file_open(mod->ctx, path);
        if (file == NULL)
                return -errno;

        size = kmod_file_get_size(file);
        mem = kmod_file_get_contents(file);

        elf = kmod_elf_new(mem, size);
        if (elf == NULL) {
                ret = -errno;
                goto elf_open_error;
        }

        count = kmod_elf_get_strings(elf, ".modinfo", &strings);
        if (count < 0) {
                ret = count;
                goto get_strings_error;
        }

        for (i = 0; i < count; i++) {
                struct kmod_module_info *info;
                struct kmod_list *n;
                const char *key, *value;
                size_t keylen, valuelen;

                key = strings[i];
                value = strchr(key, '=');
                if (value == NULL) {
                        keylen = strlen(key);
                        valuelen = 0;
                } else {
                        keylen = value - key;
                        value++;
                        valuelen = strlen(value);
                }

                info = kmod_module_info_new(key, keylen, value, valuelen);
                if (info == NULL) {
                        ret = -errno;
                        kmod_module_info_free_list(*list);
                        *list = NULL;
                        goto list_error;
                }

                n = kmod_list_append(*list, info);
                if (n != NULL)
                        *list = n;
                else {
                        kmod_module_info_free(info);
                        kmod_module_info_free_list(*list);
                        *list = NULL;
                        ret = -ENOMEM;
                        goto list_error;
                }
        }
        ret = count;

list_error:
        free(strings);
get_strings_error:
        kmod_elf_unref(elf);
elf_open_error:
        kmod_file_unref(file);

        return ret;
}

/**
 * kmod_module_info_get_key:
 * @entry: a list entry representing a kmod module info
 *
 * Get the key of a kmod module info.
 *
 * Returns: the key of this kmod module info on success or NULL on
 * failure. The string is owned by the info, do not free it.
 */
KMOD_EXPORT const char *kmod_module_info_get_key(const struct kmod_list *entry)
{
        struct kmod_module_info *info;

        if (entry == NULL)
                return NULL;

        info = entry->data;
        return info->key;
}

/**
 * kmod_module_info_get_value:
 * @entry: a list entry representing a kmod module info
 *
 * Get the value of a kmod module info.
 *
 * Returns: the value of this kmod module info on success or NULL on
 * failure. The string is owned by the info, do not free it.
 */
KMOD_EXPORT const char *kmod_module_info_get_value(const struct kmod_list *entry)
{
        struct kmod_module_info *info;

        if (entry == NULL)
                return NULL;

        info = entry->data;
        return info->value;
}

/**
 * kmod_module_info_free_list:
 * @list: kmod module info list
 *
 * Release the resources taken by @list
 */
KMOD_EXPORT void kmod_module_info_free_list(struct kmod_list *list)
{
        while (list) {
                kmod_module_info_free(list->data);
                list = kmod_list_remove(list);
        }
}

struct kmod_module_version {
        uint64_t crc;
        char symbol[];
};

static struct kmod_module_version *kmod_module_versions_new(uint64_t crc, const char *symbol)
{
        struct kmod_module_version *mv;
        size_t symbollen = strlen(symbol) + 1;

        mv = malloc(sizeof(struct kmod_module_version) + symbollen);
        if (mv == NULL)
                return NULL;

        mv->crc = crc;
        memcpy(mv->symbol, symbol, symbollen);
        return mv;
}

static void kmod_module_version_free(struct kmod_module_version *version)
{
        free(version);
}

/**
 * kmod_module_get_versions:
 * @mod: kmod module
 * @list: where to return list of module versions. Use
 *        kmod_module_version_get_symbol() and
 *        kmod_module_version_get_crc(). Release this list with
 *        kmod_module_versions_free_list()
 *
 * Get a list of entries in ELF section "__versions".
 *
 * After use, free the @list by calling kmod_module_versions_free_list().
 *
 * Returns: 0 on success or < 0 otherwise.
 */
KMOD_EXPORT int kmod_module_get_versions(const struct kmod_module *mod, struct kmod_list **list)
{
        struct kmod_file *file;
        struct kmod_elf *elf;
        const char *path;
        const void *mem;
        struct kmod_modversion *versions;
        size_t size;
        int i, count, ret = 0;

        if (mod == NULL || list == NULL)
                return -ENOENT;

        assert(*list == NULL);

        path = kmod_module_get_path(mod);
        if (path == NULL)
                return -ENOENT;

        file = kmod_file_open(mod->ctx, path);
        if (file == NULL)
                return -errno;

        size = kmod_file_get_size(file);
        mem = kmod_file_get_contents(file);

        elf = kmod_elf_new(mem, size);
        if (elf == NULL) {
                ret = -errno;
                goto elf_open_error;
        }

        count = kmod_elf_get_modversions(elf, &versions);
        if (count < 0) {
                ret = count;
                goto get_strings_error;
        }

        for (i = 0; i < count; i++) {
                struct kmod_module_version *mv;
                struct kmod_list *n;

                mv = kmod_module_versions_new(versions[i].crc, versions[i].symbol);
                if (mv == NULL) {
                        ret = -errno;
                        kmod_module_versions_free_list(*list);
                        *list = NULL;
                        goto list_error;
                }

                n = kmod_list_append(*list, mv);
                if (n != NULL)
                        *list = n;
                else {
                        kmod_module_version_free(mv);
                        kmod_module_versions_free_list(*list);
                        *list = NULL;
                        ret = -ENOMEM;
                        goto list_error;
                }
        }
        ret = count;

list_error:
        free(versions);
get_strings_error:
        kmod_elf_unref(elf);
elf_open_error:
        kmod_file_unref(file);

        return ret;
}

/**
 * kmod_module_versions_get_symbol:
 * @entry: a list entry representing a kmod module versions
 *
 * Get the symbol of a kmod module versions.
 *
 * Returns: the symbol of this kmod module versions on success or NULL
 * on failure. The string is owned by the versions, do not free it.
 */
KMOD_EXPORT const char *kmod_module_version_get_symbol(const struct kmod_list *entry)
{
        struct kmod_module_version *version;

        if (entry == NULL)
                return NULL;

        version = entry->data;
        return version->symbol;
}

/**
 * kmod_module_version_get_crc:
 * @entry: a list entry representing a kmod module version
 *
 * Get the crc of a kmod module version.
 *
 * Returns: the crc of this kmod module version on success or NULL on
 * failure. The string is owned by the version, do not free it.
 */
KMOD_EXPORT uint64_t kmod_module_version_get_crc(const struct kmod_list *entry)
{
        struct kmod_module_version *version;

        if (entry == NULL)
                return 0;

        version = entry->data;
        return version->crc;
}

/**
 * kmod_module_versions_free_list:
 * @list: kmod module versions list
 *
 * Release the resources taken by @list
 */
KMOD_EXPORT void kmod_module_versions_free_list(struct kmod_list *list)
{
        while (list) {
                kmod_module_version_free(list->data);
                list = kmod_list_remove(list);
        }
}

struct kmod_module_symbol {
        uint64_t crc;
        char symbol[];
};

static struct kmod_module_symbol *kmod_module_symbols_new(uint64_t crc, const char *symbol)
{
        struct kmod_module_symbol *mv;
        size_t symbollen = strlen(symbol) + 1;

        mv = malloc(sizeof(struct kmod_module_symbol) + symbollen);
        if (mv == NULL)
                return NULL;

        mv->crc = crc;
        memcpy(mv->symbol, symbol, symbollen);
        return mv;
}

static void kmod_module_symbol_free(struct kmod_module_symbol *symbol)
{
        free(symbol);
}

/**
 * kmod_module_get_symbols:
 * @mod: kmod module
 * @list: where to return list of module symbols. Use
 *        kmod_module_symbol_get_symbol() and
 *        kmod_module_symbol_get_crc(). Release this list with
 *        kmod_module_symbols_free_list()
 *
 * Get a list of entries in ELF section ".symtab" or "__ksymtab_strings".
 *
 * After use, free the @list by calling kmod_module_symbols_free_list().
 *
 * Returns: 0 on success or < 0 otherwise.
 */
KMOD_EXPORT int kmod_module_get_symbols(const struct kmod_module *mod, struct kmod_list **list)
{
        struct kmod_file *file;
        struct kmod_elf *elf;
        const char *path;
        const void *mem;
        struct kmod_modversion *symbols;
        size_t size;
        int i, count, ret = 0;

        if (mod == NULL || list == NULL)
                return -ENOENT;

        assert(*list == NULL);

        path = kmod_module_get_path(mod);
        if (path == NULL)
                return -ENOENT;

        file = kmod_file_open(mod->ctx, path);
        if (file == NULL)
                return -errno;

        size = kmod_file_get_size(file);
        mem = kmod_file_get_contents(file);

        elf = kmod_elf_new(mem, size);
        if (elf == NULL) {
                ret = -errno;
                goto elf_open_error;
        }

        count = kmod_elf_get_symbols(elf, &symbols);
        if (count < 0) {
                ret = count;
                goto get_strings_error;
        }

        for (i = 0; i < count; i++) {
                struct kmod_module_symbol *mv;
                struct kmod_list *n;

                mv = kmod_module_symbols_new(symbols[i].crc, symbols[i].symbol);
                if (mv == NULL) {
                        ret = -errno;
                        kmod_module_symbols_free_list(*list);
                        *list = NULL;
                        goto list_error;
                }

                n = kmod_list_append(*list, mv);
                if (n != NULL)
                        *list = n;
                else {
                        kmod_module_symbol_free(mv);
                        kmod_module_symbols_free_list(*list);
                        *list = NULL;
                        ret = -ENOMEM;
                        goto list_error;
                }
        }
        ret = count;

list_error:
        free(symbols);
get_strings_error:
        kmod_elf_unref(elf);
elf_open_error:
        kmod_file_unref(file);

        return ret;
}

/**
 * kmod_module_symbol_get_symbol:
 * @entry: a list entry representing a kmod module symbols
 *
 * Get the symbol of a kmod module symbols.
 *
 * Returns: the symbol of this kmod module symbols on success or NULL
 * on failure. The string is owned by the symbols, do not free it.
 */
KMOD_EXPORT const char *kmod_module_symbol_get_symbol(const struct kmod_list *entry)
{
        struct kmod_module_symbol *symbol;

        if (entry == NULL)
                return NULL;

        symbol = entry->data;
        return symbol->symbol;
}

/**
 * kmod_module_symbol_get_crc:
 * @entry: a list entry representing a kmod module symbol
 *
 * Get the crc of a kmod module symbol.
 *
 * Returns: the crc of this kmod module symbol on success or NULL on
 * failure. The string is owned by the symbol, do not free it.
 */
KMOD_EXPORT uint64_t kmod_module_symbol_get_crc(const struct kmod_list *entry)
{
        struct kmod_module_symbol *symbol;

        if (entry == NULL)
                return 0;

        symbol = entry->data;
        return symbol->crc;
}

/**
 * kmod_module_symbols_free_list:
 * @list: kmod module symbols list
 *
 * Release the resources taken by @list
 */
KMOD_EXPORT void kmod_module_symbols_free_list(struct kmod_list *list)
{
        while (list) {
                kmod_module_symbol_free(list->data);
                list = kmod_list_remove(list);
        }
}

struct kmod_module_dependency_symbol {
        uint64_t crc;
        uint8_t bind;
        char symbol[];
};

static struct kmod_module_dependency_symbol *kmod_module_dependency_symbols_new(uint64_t crc, uint8_t bind, const char *symbol)
{
        struct kmod_module_dependency_symbol *mv;
        size_t symbollen = strlen(symbol) + 1;

        mv = malloc(sizeof(struct kmod_module_dependency_symbol) + symbollen);
        if (mv == NULL)
                return NULL;

        mv->crc = crc;
        mv->bind = bind;
        memcpy(mv->symbol, symbol, symbollen);
        return mv;
}

static void kmod_module_dependency_symbol_free(struct kmod_module_dependency_symbol *dependency_symbol)
{
        free(dependency_symbol);
}

/**
 * kmod_module_get_dependency_symbols:
 * @mod: kmod module
 * @list: where to return list of module dependency_symbols. Use
 *        kmod_module_dependency_symbol_get_symbol() and
 *        kmod_module_dependency_symbol_get_crc(). Release this list with
 *        kmod_module_dependency_symbols_free_list()
 *
 * Get a list of entries in ELF section ".symtab" or "__ksymtab_strings".
 *
 * After use, free the @list by calling
 * kmod_module_dependency_symbols_free_list().
 *
 * Returns: 0 on success or < 0 otherwise.
 */
KMOD_EXPORT int kmod_module_get_dependency_symbols(const struct kmod_module *mod, struct kmod_list **list)
{
        struct kmod_file *file;
        struct kmod_elf *elf;
        const char *path;
        const void *mem;
        struct kmod_modversion *symbols;
        size_t size;
        int i, count, ret = 0;

        if (mod == NULL || list == NULL)
                return -ENOENT;

        assert(*list == NULL);

        path = kmod_module_get_path(mod);
        if (path == NULL)
                return -ENOENT;

        file = kmod_file_open(mod->ctx, path);
        if (file == NULL)
                return -errno;

        size = kmod_file_get_size(file);
        mem = kmod_file_get_contents(file);

        elf = kmod_elf_new(mem, size);
        if (elf == NULL) {
                ret = -errno;
                goto elf_open_error;
        }

        count = kmod_elf_get_dependency_symbols(elf, &symbols);
        if (count < 0) {
                ret = count;
                goto get_strings_error;
        }

        for (i = 0; i < count; i++) {
                struct kmod_module_dependency_symbol *mv;
                struct kmod_list *n;

                mv = kmod_module_dependency_symbols_new(symbols[i].crc,
                                                        symbols[i].bind,
                                                        symbols[i].symbol);
                if (mv == NULL) {
                        ret = -errno;
                        kmod_module_dependency_symbols_free_list(*list);
                        *list = NULL;
                        goto list_error;
                }

                n = kmod_list_append(*list, mv);
                if (n != NULL)
                        *list = n;
                else {
                        kmod_module_dependency_symbol_free(mv);
                        kmod_module_dependency_symbols_free_list(*list);
                        *list = NULL;
                        ret = -ENOMEM;
                        goto list_error;
                }
        }
        ret = count;

list_error:
        free(symbols);
get_strings_error:
        kmod_elf_unref(elf);
elf_open_error:
        kmod_file_unref(file);

        return ret;
}

/**
 * kmod_module_dependency_symbol_get_symbol:
 * @entry: a list entry representing a kmod module dependency_symbols
 *
 * Get the dependency symbol of a kmod module
 *
 * Returns: the symbol of this kmod module dependency_symbols on success or NULL
 * on failure. The string is owned by the dependency_symbols, do not free it.
 */
KMOD_EXPORT const char *kmod_module_dependency_symbol_get_symbol(const struct kmod_list *entry)
{
        struct kmod_module_dependency_symbol *dependency_symbol;

        if (entry == NULL)
                return NULL;

        dependency_symbol = entry->data;
        return dependency_symbol->symbol;
}

/**
 * kmod_module_dependency_symbol_get_crc:
 * @entry: a list entry representing a kmod module dependency_symbol
 *
 * Get the crc of a kmod module dependency_symbol.
 *
 * Returns: the crc of this kmod module dependency_symbol on success or NULL on
 * failure. The string is owned by the dependency_symbol, do not free it.
 */
KMOD_EXPORT uint64_t kmod_module_dependency_symbol_get_crc(const struct kmod_list *entry)
{
        struct kmod_module_dependency_symbol *dependency_symbol;

        if (entry == NULL)
                return 0;

        dependency_symbol = entry->data;
        return dependency_symbol->crc;
}

/**
 * kmod_module_dependency_symbol_get_bind:
 * @entry: a list entry representing a kmod module dependency_symbol
 *
 * Get the bind type of a kmod module dependency_symbol.
 *
 * Returns: the bind of this kmod module dependency_symbol on success
 * or < 0 on failure.
 */
KMOD_EXPORT int kmod_module_dependency_symbol_get_bind(const struct kmod_list *entry)
{
        struct kmod_module_dependency_symbol *dependency_symbol;

        if (entry == NULL)
                return 0;

        dependency_symbol = entry->data;
        return dependency_symbol->bind;
}

/**
 * kmod_module_dependency_symbols_free_list:
 * @list: kmod module dependency_symbols list
 *
 * Release the resources taken by @list
 */
KMOD_EXPORT void kmod_module_dependency_symbols_free_list(struct kmod_list *list)
{
        while (list) {
                kmod_module_dependency_symbol_free(list->data);
                list = kmod_list_remove(list);
        }
}