libkmod/libkmod.c

// SPDX-License-Identifier: LGPL-2.1-or-later
/*
 * Copyright (C) 2011-2013  ProFUSION embedded systems
 */

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <fnmatch.h>
#include <limits.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/utsname.h>

#include <shared/hash.h>
#include <shared/util.h>

#include "libkmod.h"
#include "libkmod-internal.h"
#include "libkmod-index.h"

#define KMOD_HASH_SIZE (256)
#define KMOD_LRU_MAX (128)
#define _KMOD_INDEX_MODULES_SIZE KMOD_INDEX_MODULES_BUILTIN + 1

static const struct {
	const char *fn;
	bool alias_prefix;
} index_files[] = {
	// clang-format off
	[KMOD_INDEX_MODULES_DEP] = { .fn = "modules.dep" },
	[KMOD_INDEX_MODULES_ALIAS] = { .fn = "modules.alias", .alias_prefix = true },
	[KMOD_INDEX_MODULES_SYMBOL] = { .fn = "modules.symbols", .alias_prefix = true },
	[KMOD_INDEX_MODULES_BUILTIN_ALIAS] = { .fn = "modules.builtin.alias" },
	[KMOD_INDEX_MODULES_BUILTIN] = { .fn = "modules.builtin" },
	// clang-format on
};

static const char *const default_config_paths[] = {
	// clang-format off
	SYSCONFDIR "/modprobe.d",
	"/run/modprobe.d",
	"/usr/local/lib/modprobe.d",
	DISTCONFDIR "/modprobe.d",
	"/lib/modprobe.d",
	NULL,
	// clang-format on
};

struct kmod_ctx {
	int refcount;
	int log_priority;
	void (*log_fn)(void *data, int priority, const char *file, int line,
		       const char *fn, const char *format, va_list args);
	void *log_data;
	const void *userdata;
	char *dirname;
	enum kmod_file_compression_type kernel_compression;
	struct kmod_config *config;
	struct hash *modules_by_name;
	struct index_mm *indexes[_KMOD_INDEX_MODULES_SIZE];
	unsigned long long indexes_stamp[_KMOD_INDEX_MODULES_SIZE];
};

void kmod_log(const struct kmod_ctx *ctx, int priority, const char *file, int line,
	      const char *fn, const char *format, ...)
{
	va_list args;

	if (ctx->log_fn == NULL)
		return;

	va_start(args, format);
	ctx->log_fn(ctx->log_data, priority, file, line, fn, format, args);
	va_end(args);
}

_printf_format_(6, 0) static void log_filep(void *data, int priority, const char *file,
					    int line, const char *fn, const char *format,
					    va_list args)
{
	FILE *fp = data;
	char buf[16];
	const char *priname;
	switch (priority) {
	case LOG_EMERG:
		priname = "EMERGENCY";
		break;
	case LOG_ALERT:
		priname = "ALERT";
		break;
	case LOG_CRIT:
		priname = "CRITICAL";
		break;
	case LOG_ERR:
		priname = "ERROR";
		break;
	case LOG_WARNING:
		priname = "WARNING";
		break;
	case LOG_NOTICE:
		priname = "NOTICE";
		break;
	case LOG_INFO:
		priname = "INFO";
		break;
	case LOG_DEBUG:
		priname = "DEBUG";
		break;
	default:
		snprintf(buf, sizeof(buf), "L:%d", priority);
		priname = buf;
	}
	if (ENABLE_DEBUG == 1)
		fprintf(fp, "libkmod: %s %s:%d %s: ", priname, file, line, fn);
	else
		fprintf(fp, "libkmod: %s: %s: ", priname, fn);
	vfprintf(fp, format, args);
}

KMOD_EXPORT const char *kmod_get_dirname(const struct kmod_ctx *ctx)
{
	if (ctx == NULL)
		return NULL;

	return ctx->dirname;
}

KMOD_EXPORT void *kmod_get_userdata(const struct kmod_ctx *ctx)
{
	if (ctx == NULL)
		return NULL;
	return (void *)ctx->userdata;
}

KMOD_EXPORT void kmod_set_userdata(struct kmod_ctx *ctx, const void *userdata)
{
	if (ctx == NULL)
		return;
	ctx->userdata = userdata;
}

static int log_priority(const char *priority)
{
	char *endptr;
	long prio;

	errno = 0;
	prio = strtol(priority, &endptr, 10);
	if (errno == ERANGE || prio < INT_MIN || prio > INT_MAX)
		return 0;
	if (endptr[0] == '\0' || isspace(endptr[0]))
		return prio;
	if (strstartswith(priority, "err"))
		return LOG_ERR;
	if (strstartswith(priority, "info"))
		return LOG_INFO;
	if (strstartswith(priority, "debug"))
		return LOG_DEBUG;
	return 0;
}

static const char *dirname_default_prefix = MODULE_DIRECTORY;

static char *get_kernel_release(const char *dirname)
{
	struct utsname u;
	char *p;

	if (dirname != NULL)
		return path_make_absolute_cwd(dirname);

	if (uname(&u) < 0)
		return NULL;

	if (asprintf(&p, "%s/%s", dirname_default_prefix, u.release) < 0)
		return NULL;

	return p;
}

static enum kmod_file_compression_type get_kernel_compression(struct kmod_ctx *ctx)
{
	const char *path = "/sys/module/compression";
	char buf[16];
	int fd;
	int err;

	fd = open(path, O_RDONLY | O_CLOEXEC);
	if (fd < 0) {
		/* Not having the file is not an error: kernel may be too old */
		DBG(ctx, "could not open '%s' for reading: %m\n", path);
		return KMOD_FILE_COMPRESSION_NONE;
	}

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

	if (streq(buf, "zstd\n"))
		return KMOD_FILE_COMPRESSION_ZSTD;
	else if (streq(buf, "xz\n"))
		return KMOD_FILE_COMPRESSION_XZ;
	else if (streq(buf, "gzip\n"))
		return KMOD_FILE_COMPRESSION_ZLIB;

	ERR(ctx, "unknown kernel compression %s", buf);

	return KMOD_FILE_COMPRESSION_NONE;
}

KMOD_EXPORT struct kmod_ctx *kmod_new(const char *dirname, const char *const *config_paths)
{
	const char *env;
	struct kmod_ctx *ctx;
	int err;

	ctx = calloc(1, sizeof(struct kmod_ctx));
	if (!ctx)
		return NULL;

	ctx->refcount = 1;
	ctx->log_fn = log_filep;
	ctx->log_data = stderr;
	ctx->log_priority = LOG_ERR;

	ctx->dirname = get_kernel_release(dirname);
	if (ctx->dirname == NULL) {
		ERR(ctx, "could not retrieve directory\n");
		goto fail;
	}

	/* environment overwrites config */
	env = secure_getenv("KMOD_LOG");
	if (env != NULL)
		kmod_set_log_priority(ctx, log_priority(env));

	ctx->kernel_compression = get_kernel_compression(ctx);

	if (config_paths == NULL)
		config_paths = default_config_paths;
	err = kmod_config_new(ctx, &ctx->config, config_paths);
	if (err < 0) {
		ERR(ctx, "could not create config\n");
		goto fail;
	}

	ctx->modules_by_name = hash_new(KMOD_HASH_SIZE, NULL);
	if (ctx->modules_by_name == NULL) {
		ERR(ctx, "could not create by-name hash\n");
		goto fail;
	}

	INFO(ctx, "ctx %p created\n", ctx);
	DBG(ctx, "log_priority=%d\n", ctx->log_priority);

	return ctx;

fail:
	free(ctx->modules_by_name);
	free(ctx->dirname);
	free(ctx);
	return NULL;
}

KMOD_EXPORT struct kmod_ctx *kmod_ref(struct kmod_ctx *ctx)
{
	if (ctx == NULL)
		return NULL;
	ctx->refcount++;
	return ctx;
}

KMOD_EXPORT struct kmod_ctx *kmod_unref(struct kmod_ctx *ctx)
{
	if (ctx == NULL)
		return NULL;

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

	INFO(ctx, "context %p released\n", ctx);

	kmod_unload_resources(ctx);
	hash_free(ctx->modules_by_name);
	free(ctx->dirname);
	if (ctx->config)
		kmod_config_free(ctx->config);

	free(ctx);
	return NULL;
}

KMOD_EXPORT void kmod_set_log_fn(struct kmod_ctx *ctx,
				 void (*log_fn)(void *data, int priority,
						const char *file, int line, const char *fn,
						const char *format, va_list args),
				 const void *data)
{
	if (ctx == NULL)
		return;
	ctx->log_fn = log_fn;
	ctx->log_data = (void *)data;
	INFO(ctx, "custom logging function %p registered\n", log_fn);
}

KMOD_EXPORT int kmod_get_log_priority(const struct kmod_ctx *ctx)
{
	if (ctx == NULL)
		return -1;
	return ctx->log_priority;
}

KMOD_EXPORT void kmod_set_log_priority(struct kmod_ctx *ctx, int priority)
{
	if (ctx == NULL)
		return;
	ctx->log_priority = priority;
}

struct kmod_module *kmod_pool_get_module(struct kmod_ctx *ctx, const char *key)
{
	struct kmod_module *mod;

	mod = hash_find(ctx->modules_by_name, key);

	DBG(ctx, "get module name='%s' found=%p\n", key, mod);

	return mod;
}

int kmod_pool_add_module(struct kmod_ctx *ctx, struct kmod_module *mod, const char *key)
{
	DBG(ctx, "add %p key='%s'\n", mod, key);

	return hash_add(ctx->modules_by_name, key, mod);
}

void kmod_pool_del_module(struct kmod_ctx *ctx, struct kmod_module *mod, const char *key)
{
	DBG(ctx, "del %p key='%s'\n", mod, key);

	hash_del(ctx->modules_by_name, key);
}

static int kmod_lookup_alias_from_alias_bin(struct kmod_ctx *ctx,
					    enum kmod_index index_number,
					    const char *name, struct kmod_list **list)
{
	int err, nmatch = 0;
	struct index_file *idx;
	struct index_value *realnames, *realname;

	assert(*list == NULL);

	if (ctx->indexes[index_number] != NULL) {
		DBG(ctx, "use mmapped index '%s' for name=%s\n",
		    index_files[index_number].fn, name);
		realnames = index_mm_searchwild(ctx->indexes[index_number], name);
	} else {
		char fn[PATH_MAX];

		snprintf(fn, sizeof(fn), "%s/%s.bin", ctx->dirname,
			 index_files[index_number].fn);

		DBG(ctx, "file=%s name=%s\n", fn, name);

		idx = index_file_open(fn);
		if (idx == NULL)
			return -ENOSYS;

		realnames = index_searchwild(idx, name);
		index_file_close(idx);
	}

	for (realname = realnames; realname; realname = realname->next) {
		struct kmod_module *mod;
		struct kmod_list *node;

		err = kmod_module_new_from_alias(ctx, name, realname->value, &mod);
		if (err < 0) {
			ERR(ctx, "Could not create module for alias=%s realname=%s: %s\n",
			    name, realname->value, strerror(-err));
			goto fail;
		}

		node = kmod_list_append(*list, mod);
		if (node == NULL) {
			ERR(ctx, "out of memory\n");
			kmod_module_unref(mod);
			err = -ENOMEM;
			goto fail;
		}
		*list = node;
		nmatch++;
	}

	index_values_free(realnames);
	return nmatch;

fail:
	kmod_list_release(*list, kmod_module_unref);
	index_values_free(realnames);
	return err;
}

int kmod_lookup_alias_from_symbols_file(struct kmod_ctx *ctx, const char *name,
					struct kmod_list **list)
{
	if (!strstartswith(name, "symbol:"))
		return 0;

	return kmod_lookup_alias_from_alias_bin(ctx, KMOD_INDEX_MODULES_SYMBOL, name,
						list);
}

int kmod_lookup_alias_from_aliases_file(struct kmod_ctx *ctx, const char *name,
					struct kmod_list **list)
{
	return kmod_lookup_alias_from_alias_bin(ctx, KMOD_INDEX_MODULES_ALIAS, name, list);
}

static char *lookup_file(struct kmod_ctx *ctx, enum kmod_index index_number,
			 const char *name)
{
	char *line;

	if (ctx->indexes[index_number]) {
		DBG(ctx, "use mmapped index '%s' modname=%s\n",
		    index_files[index_number].fn, name);
		line = index_mm_search(ctx->indexes[index_number], name);
	} else {
		struct index_file *idx;
		char fn[PATH_MAX];

		snprintf(fn, sizeof(fn), "%s/%s.bin", ctx->dirname,
			 index_files[index_number].fn);
		DBG(ctx, "file=%s modname=%s\n", fn, name);

		idx = index_file_open(fn);
		if (idx == NULL) {
			DBG(ctx, "could not open builtin file '%s'\n", fn);
			return NULL;
		}

		line = index_search(idx, name);
		index_file_close(idx);
	}

	return line;
}

static bool lookup_builtin_file(struct kmod_ctx *ctx, const char *name)
{
	_cleanup_free_ char *line = lookup_file(ctx, KMOD_INDEX_MODULES_BUILTIN, name);

	return line;
}

int kmod_lookup_alias_from_kernel_builtin_file(struct kmod_ctx *ctx, const char *name,
					       struct kmod_list **list)
{
	struct kmod_list *l;
	int ret;

	ret = kmod_lookup_alias_from_alias_bin(ctx, KMOD_INDEX_MODULES_BUILTIN_ALIAS,
					       name, list);

	kmod_list_foreach(l, *list) {
		struct kmod_module *mod = l->data;
		kmod_module_set_builtin(mod, true);
	}

	return ret;
}

int kmod_lookup_alias_from_builtin_file(struct kmod_ctx *ctx, const char *name,
					struct kmod_list **list)
{
	assert(*list == NULL);

	if (lookup_builtin_file(ctx, name)) {
		struct kmod_module *mod;
		struct kmod_list *node;
		int err;

		err = kmod_module_new_from_name(ctx, name, &mod);
		if (err < 0) {
			ERR(ctx, "Could not create module from name %s: %s\n", name,
			    strerror(-err));
			return err;
		}

		/* already mark it as builtin since it's being created from
		 * this index */
		kmod_module_set_builtin(mod, true);
		node = kmod_list_append(*list, mod);
		if (node == NULL) {
			ERR(ctx, "out of memory\n");
			kmod_module_unref(mod);
			return -ENOMEM;
		}
		*list = node;
	}

	return 0;
}

bool kmod_lookup_alias_is_builtin(struct kmod_ctx *ctx, const char *name)
{
	return lookup_builtin_file(ctx, name);
}

char *kmod_search_moddep(struct kmod_ctx *ctx, const char *name)
{
	return lookup_file(ctx, KMOD_INDEX_MODULES_DEP, name);
}

int kmod_lookup_alias_from_moddep_file(struct kmod_ctx *ctx, const char *name,
				       struct kmod_list **list)
{
	char *line;
	int n = 0;

	assert(*list == NULL);

	/*
	 * Module names do not contain ':'. Return early if we know it will
	 * not be found.
	 */
	if (strchr(name, ':'))
		return 0;

	line = kmod_search_moddep(ctx, name);
	if (line != NULL) {
		struct kmod_module *mod;
		struct kmod_list *node;

		n = kmod_module_new_from_name(ctx, name, &mod);
		if (n < 0) {
			ERR(ctx, "Could not create module from name %s: %s\n", name,
			    strerror(-n));
			goto finish;
		}

		node = kmod_list_append(*list, mod);
		if (node == NULL) {
			ERR(ctx, "out of memory\n");
			kmod_module_unref(mod);
			n = -ENOMEM;
			goto finish;
		}
		*list = node;
		kmod_module_parse_depline(mod, line);
	}

finish:
	free(line);

	return n;
}

int kmod_lookup_alias_from_config(struct kmod_ctx *ctx, const char *name,
				  struct kmod_list **list)
{
	struct kmod_config *config = ctx->config;
	struct kmod_list *l;
	int err, nmatch = 0;

	assert(*list == NULL);

	kmod_list_foreach(l, config->aliases) {
		const char *aliasname = kmod_alias_get_name(l);
		const char *modname = kmod_alias_get_modname(l);

		if (fnmatch(aliasname, name, 0) == 0) {
			struct kmod_module *mod;
			struct kmod_list *node;

			err = kmod_module_new_from_alias(ctx, aliasname, modname, &mod);
			if (err < 0) {
				ERR(ctx,
				    "Could not create module for alias=%s modname=%s: %s\n",
				    name, modname, strerror(-err));
				goto fail;
			}

			node = kmod_list_append(*list, mod);
			if (node == NULL) {
				ERR(ctx, "out of memory\n");
				kmod_module_unref(mod);
				err = -ENOMEM;
				goto fail;
			}
			*list = node;
			nmatch++;
		}
	}

	return nmatch;

fail:
	kmod_list_release(*list, kmod_module_unref);
	return err;
}

int kmod_lookup_alias_from_commands(struct kmod_ctx *ctx, const char *name,
				    struct kmod_list **list)
{
	struct kmod_config *config = ctx->config;
	struct kmod_list *l, *node;
	int err, nmatch = 0;

	assert(*list == NULL);

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

		if (streq(modname, name)) {
			const char *cmd = kmod_command_get_command(l);
			struct kmod_module *mod;

			err = kmod_module_new_from_name(ctx, modname, &mod);
			if (err < 0) {
				ERR(ctx, "Could not create module from name %s: %s\n",
				    modname, strerror(-err));
				return err;
			}

			node = kmod_list_append(*list, mod);
			if (node == NULL) {
				ERR(ctx, "out of memory\n");
				kmod_module_unref(mod);
				return -ENOMEM;
			}

			*list = node;
			nmatch = 1;

			kmod_module_set_install_commands(mod, cmd);

			/*
			 * match only the first one, like modprobe from
			 * module-init-tools does
			 */
			break;
		}
	}

	if (nmatch)
		return nmatch;

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

		if (streq(modname, name)) {
			const char *cmd = kmod_command_get_command(l);
			struct kmod_module *mod;

			err = kmod_module_new_from_name(ctx, modname, &mod);
			if (err < 0) {
				ERR(ctx, "Could not create module from name %s: %s\n",
				    modname, strerror(-err));
				return err;
			}

			node = kmod_list_append(*list, mod);
			if (node == NULL) {
				ERR(ctx, "out of memory\n");
				kmod_module_unref(mod);
				return -ENOMEM;
			}

			*list = node;
			nmatch = 1;

			kmod_module_set_remove_commands(mod, cmd);

			/*
			 * match only the first one, like modprobe from
			 * module-init-tools does
			 */
			break;
		}
	}

	return nmatch;
}

void kmod_set_modules_visited(struct kmod_ctx *ctx, bool visited)
{
	struct hash_iter iter;
	const void *v;

	hash_iter_init(ctx->modules_by_name, &iter);
	while (hash_iter_next(&iter, NULL, &v))
		kmod_module_set_visited((struct kmod_module *)v, visited);
}

void kmod_set_modules_required(struct kmod_ctx *ctx, bool required)
{
	struct hash_iter iter;
	const void *v;

	hash_iter_init(ctx->modules_by_name, &iter);
	while (hash_iter_next(&iter, NULL, &v))
		kmod_module_set_required((struct kmod_module *)v, required);
}

static bool is_cache_invalid(const char *path, unsigned long long stamp)
{
	struct stat st;

	if (stat(path, &st) < 0)
		return true;

	if (stamp != stat_mstamp(&st))
		return true;

	return false;
}

KMOD_EXPORT int kmod_validate_resources(struct kmod_ctx *ctx)
{
	struct kmod_list *l;
	size_t i;

	if (ctx == NULL || ctx->config == NULL)
		return KMOD_RESOURCES_MUST_RECREATE;

	kmod_list_foreach(l, ctx->config->paths) {
		struct kmod_config_path *cf = l->data;

		if (is_cache_invalid(cf->path, cf->stamp))
			return KMOD_RESOURCES_MUST_RECREATE;
	}

	for (i = 0; i < _KMOD_INDEX_MODULES_SIZE; i++) {
		char path[PATH_MAX];

		if (ctx->indexes[i] == NULL)
			continue;

		snprintf(path, sizeof(path), "%s/%s.bin", ctx->dirname, index_files[i].fn);

		if (is_cache_invalid(path, ctx->indexes_stamp[i]))
			return KMOD_RESOURCES_MUST_RELOAD;
	}

	return KMOD_RESOURCES_OK;
}

KMOD_EXPORT int kmod_load_resources(struct kmod_ctx *ctx)
{
	int ret = 0;
	size_t i;

	if (ctx == NULL)
		return -ENOENT;

	for (i = 0; i < _KMOD_INDEX_MODULES_SIZE; i++) {
		char path[PATH_MAX];

		if (ctx->indexes[i] != NULL) {
			INFO(ctx, "Index %s already loaded\n", index_files[i].fn);
			continue;
		}

		snprintf(path, sizeof(path), "%s/%s.bin", ctx->dirname, index_files[i].fn);
		ret = index_mm_open(ctx, path, &ctx->indexes_stamp[i], &ctx->indexes[i]);

		/*
		 * modules.builtin.alias are considered optional since it's
		 * recently added and older installations may not have it;
		 * we allow failing for any reason
		 */
		if (ret) {
			if (i != KMOD_INDEX_MODULES_BUILTIN_ALIAS)
				break;
			ret = 0;
		}
	}

	if (ret)
		kmod_unload_resources(ctx);

	return ret;
}

KMOD_EXPORT void kmod_unload_resources(struct kmod_ctx *ctx)
{
	size_t i;

	if (ctx == NULL)
		return;

	for (i = 0; i < _KMOD_INDEX_MODULES_SIZE; i++) {
		if (ctx->indexes[i] != NULL) {
			index_mm_close(ctx->indexes[i]);
			ctx->indexes[i] = NULL;
			ctx->indexes_stamp[i] = 0;
		}
	}
}

KMOD_EXPORT int kmod_dump_index(struct kmod_ctx *ctx, enum kmod_index type, int fd)
{
	if (ctx == NULL)
		return -ENOSYS;

#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wtautological-unsigned-enum-zero-compare"
#endif
	if (type < 0 || type >= _KMOD_INDEX_MODULES_SIZE)
		return -ENOENT;
#if defined(__clang__)
#pragma clang diagnostic pop
#endif

	if (ctx->indexes[type] != NULL) {
		DBG(ctx, "use mmapped index '%s'\n", index_files[type].fn);
		index_mm_dump(ctx->indexes[type], fd, index_files[type].alias_prefix);
	} else {
		char fn[PATH_MAX];
		struct index_file *idx;

		snprintf(fn, sizeof(fn), "%s/%s.bin", ctx->dirname, index_files[type].fn);

		DBG(ctx, "file=%s\n", fn);

		idx = index_file_open(fn);
		if (idx == NULL)
			return -ENOSYS;

		index_dump(idx, fd, index_files[type].alias_prefix);
		index_file_close(idx);
	}

	return 0;
}

const struct kmod_config *kmod_get_config(const struct kmod_ctx *ctx)
{
	return ctx->config;
}

enum kmod_file_compression_type kmod_get_kernel_compression(const struct kmod_ctx *ctx)
{
	return ctx->kernel_compression;
}