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 version 2.1.
 *
 * 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 <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;
	const char *path;
	const char *name;
	struct kmod_list *dep;
	int refcount;
	struct {
		bool dep : 1;
	} init;
};

static char *path_to_modname(const char *path, bool alloc)
{
	char *modname;
	char *c;

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

	if (alloc)
		modname = strdup(modname);

	for (c = modname; *c != '\0' && *c != '.'; c++) {
		if (*c == '-')
			*c = '_';
	}

	*c = '\0';
	return modname;
}

static const char *get_modname(struct kmod_module *mod)
{
	if (mod->name == NULL)
		mod->name = path_to_modname(mod->path, true);

	return mod->name;
}

int kmod_module_parse_dep(struct kmod_module *mod, char *line)
{
	struct kmod_ctx *ctx = mod->ctx;
	struct kmod_list *list = NULL;
	char *p, *saveptr;
	int err, n = 0;

	assert(!mod->init.dep && mod->dep == NULL);
	mod->init.dep = true;

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

	p++;

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

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

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

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

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

	mod->dep = list;
	return n;

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

KMOD_EXPORT int kmod_module_new_from_name(struct kmod_ctx *ctx,
						const char *name,
						struct kmod_module **mod)
{
	struct kmod_module *m;

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

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

	m->ctx = kmod_ref(ctx);
	m->name = strdup(name);
	m->refcount = 1;

	*mod = m;

	return 0;
}

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;

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

	err = stat(path, &st);
	if (err < 0)
		return -errno;

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

	m->ctx = kmod_ref(ctx);
	m->path = strdup(path);
	m->refcount = 1;

	*mod = m;

	return 0;
}

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((char *) mod->path);
	free((char *) mod->name);
	free(mod);
	return NULL;
}

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_EXPORT int kmod_module_new_from_lookup(struct kmod_ctx *ctx,
						const char *alias,
						struct kmod_list **list)
{
	int err;

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

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

	/* 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);

	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_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;
}

/*
 * We don't increase the refcount. Maybe we should.
 */
KMOD_EXPORT struct kmod_list *kmod_module_get_dependency(const struct kmod_module *mod)
{
	// FIXME calculate dependency if it's not initialized
	return mod->dep;
}

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_EXPORT const char *kmod_module_get_name(const struct kmod_module *mod)
{
	// FIXME calculate name if name == NULL
	return mod->name;
}

KMOD_EXPORT const char *kmod_module_get_path(const struct kmod_module *mod)
{
	// FIXME calculate path if path == NULL
	return mod->path;
}


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

KMOD_EXPORT int kmod_module_remove_module(struct kmod_module *mod,
							unsigned int flags)
{
	int err;
	const char *modname;

	if (mod == NULL)
		return -ENOENT;

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

	modname = get_modname(mod);
	err = delete_module(modname, flags);
	if (err != 0) {
		ERR(mod->ctx, "Removing '%s': %s\n", modname,
							strerror(-err));
		return err;
	}

	return 0;
}

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

KMOD_EXPORT int kmod_module_insert_module(struct kmod_module *mod,
							unsigned int flags)
{
	int err;
	void *mmaped_file;
	struct stat st;
	int fd;
	const char *args = "";

	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;
}