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

/*
 * libkmod - interface to kernel module operations
 *
 * Copyright (C) 2011  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 <string.h>

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

/**
 * kmod_module:
 *
 * Opaque object representing a module.
 */
struct kmod_module {
        struct kmod_ctx *ctx;
        char *name;
        char *path;
        struct kmod_list *dep;
        char *options;
        char *install_commands;
        char *remove_commands;
        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;
};

inline char *modname_normalize(const char *modname, char buf[NAME_MAX],
                                                                size_t *len)
{
        size_t s;

        for (s = 0; s < NAME_MAX - 1; s++) {
                const char c = modname[s];
                if (c == '-')
                        buf[s] = '_';
                else if (c == '\0' || c == '.')
                        break;
                else
                        buf[s] = c;
        }

        buf[s] = '\0';

        if (len)
                *len = s;

        return buf;
}

static char *path_to_modname(const char *path, char buf[NAME_MAX], size_t *len)
{
        char *modname;

        modname = basename(path);
        if (modname == NULL || modname[0] == '\0')
                return NULL;

        return modname_normalize(modname, buf, len);
}

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;
}

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_append(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;
}

/**
 * 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 does 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)
{
        struct kmod_module *m;
        size_t namelen;
        char name_norm[NAME_MAX];

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

        alias_normalize(name, name_norm, &namelen);

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

        m = calloc(1, sizeof(*m) + namelen + 1);
        if (m == NULL) {
                free(m);
                return -ENOMEM;
        }

        m->ctx = kmod_ref(ctx);
        m->name = (char *)m + sizeof(*m);
        memcpy(m->name, name_norm, namelen + 1);
        m->refcount = 1;

        kmod_pool_add_module(ctx, m);

        *mod = m;

        return 0;
}

int kmod_module_new_from_alias(struct kmod_ctx *ctx, const char *alias,
                                const char *name, struct kmod_module **mod)
{
        int err;
        struct kmod_module *m;

        err = kmod_module_new_from_name(ctx, alias, mod);
        if (err < 0)
                return err;

        m = *mod;

        /* if module did not came from pool */
        if (m->alias == NULL) {
                m->alias = m->name;
                m->name = strdup(name);
                if (m->name == NULL)
                        goto fail_oom;
        }

        return 0;

fail_oom:
        ERR(ctx, "out of memory\n");
        kmod_module_unref(m);
        *mod = NULL;
        return err;
}

/**
 * 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[NAME_MAX];
        char *abspath;
        size_t namelen;

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

        abspath = path_make_absolute_cwd(path);
        if (abspath == NULL)
                return -ENOMEM;

        err = stat(abspath, &st);
        if (err < 0) {
                free(abspath);
                return -errno;
        }

        if (path_to_modname(path, name, &namelen) == NULL) {
                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\n",
                                                                        name);
                        free(abspath);
                        return -EEXIST;
                }

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

        m = calloc(1, sizeof(*m) + namelen + 1);
        if (m == NULL)
                return -errno;

        m->ctx = kmod_ref(ctx);
        m->name = (char *)m + sizeof(*m);
        memcpy(m->name, name, namelen);
        m->path = abspath;
        m->refcount = 1;

        kmod_pool_add_module(ctx, m);

        *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_module_unref_list(mod->dep);
        kmod_unref(mod->ctx);
        free(mod->options);
        free(mod->install_commands);
        free(mod->remove_commands);
        free(mod->path);
        if (mod->alias != NULL)
                free(mod->name);
        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[NAME_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)
                return -EINVAL;

        /* Aliases from config file override all the others */
        err = kmod_lookup_alias_from_config(ctx, alias, list);
        CHECK_ERR_AND_FINISH(err, fail, list, finish);

        err = kmod_lookup_alias_from_moddep_file(ctx, alias, list);
        CHECK_ERR_AND_FINISH(err, fail, list, finish);

        err = kmod_lookup_alias_from_symbols_file(ctx, alias, list);
        CHECK_ERR_AND_FINISH(err, fail, list, finish);

// TODO: add lookup for install commands here.

        err = kmod_lookup_alias_from_aliases_file(ctx, alias, list);
        CHECK_ERR_AND_FINISH(err, fail, list, finish);

finish:

        return err;
fail:
        kmod_module_unref_list(*list);
        *list = NULL;
        return err;
}
#undef CHECK_ERR_AND_FINISH

/**
 * kmod_module_unref:
 * @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_unref:
 * @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;

        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;
        }

        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_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", "r");
        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_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)
{
        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 (see kmod_get_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;

        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(mod->ctx, "Removing '%s': %s\n", mod->name,
                                                        strerror(-err));
                return err;
        }

        return 0;
}

extern long init_module(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 it dictates the
 * behavior of this function. They are not implemented yet.
 * @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.
 */
KMOD_EXPORT int kmod_module_insert_module(struct kmod_module *mod,
                                                        unsigned int flags,
                                                        const char *options)
{
        int err;
        void *mmaped_file;
        struct stat st;
        int fd;
        const char *args = options ? options : "";

        if (mod == NULL)
                return -ENOENT;

        if (mod->path == NULL) {
                ERR(mod->ctx, "Not supported to load a module by name yet\n");
                return -ENOSYS;
        }

        if (flags != 0)
                INFO(mod->ctx, "Flags are not implemented yet\n");

        if ((fd = open(mod->path, O_RDONLY)) < 0) {
                err = -errno;
                return err;
        }

        fstat(fd, &st);

        if ((mmaped_file = mmap(0, st.st_size, PROT_READ,
                                        MAP_PRIVATE, fd, 0)) == MAP_FAILED) {
                close(fd);
                return -errno;
        }

        err = init_module(mmaped_file, st.st_size, args);
        if (err < 0)
                ERR(mod->ctx, "Failed to insert module '%s'\n", mod->path);

        munmap(mmaped_file, st.st_size);
        close(fd);

        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, *ctx_options;
                char *opts = NULL;
                size_t optslen = 0;

                ctx_options = kmod_get_options(mod->ctx);

                kmod_list_foreach(l, ctx_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, *ctx_install_commands;
                char *cmds = NULL;
                size_t cmdslen = 0;

                ctx_install_commands = kmod_get_install_commands(mod->ctx);

                kmod_list_foreach(l, ctx_install_commands) {
                        const char *modname = kmod_command_get_modname(l);
                        const char *str;
                        size_t len;
                        void *tmp;

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

                        str = kmod_command_get_command(l);
                        len = strlen(str);
                        if (len < 1)
                                continue;

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

                        cmds = tmp;

                        if (cmdslen > 0) {
                                cmds[cmdslen] = ';';
                                cmdslen++;
                        }

                        memcpy(cmds + cmdslen, str, len);
                        cmdslen += len;
                        cmds[cmdslen] = '\0';
                }

                m->init.install_commands = true;
                m->install_commands = cmds;
        }

        return mod->install_commands;

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

/**
 * 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, *ctx_remove_commands;
                char *cmds = NULL;
                size_t cmdslen = 0;

                ctx_remove_commands = kmod_get_remove_commands(mod->ctx);

                kmod_list_foreach(l, ctx_remove_commands) {
                        const char *modname = kmod_command_get_modname(l);
                        const char *str;
                        size_t len;
                        void *tmp;

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

                        str = kmod_command_get_command(l);
                        len = strlen(str);
                        if (len < 1)
                                continue;

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

                        cmds = tmp;

                        if (cmdslen > 0) {
                                cmds[cmdslen] = ';';
                                cmdslen++;
                        }

                        memcpy(cmds + cmdslen, str, len);
                        cmdslen += len;
                        cmds[cmdslen] = '\0';
                }

                m->init.remove_commands = true;
                m->remove_commands = cmds;
        }

        return mod->remove_commands;

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

/**
 * 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", "r");
        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;

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

                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_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;

        snprintf(path, sizeof(path), "/sys/module/%s/refcnt", mod->name);
        fd = open(path, O_RDONLY);
        if (fd < 0) {
                err = -errno;
                ERR(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);
                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);
        }
}