The kernel since version v5.2-rc1 exports information about built-in modules in the modules.builtin.modinfo. Information is stored in the same format as in the separate modules (null-terminated string array). The module name is a prefix for each line. $ tr '\0' '\n' < modules.builtin.modinfo ext4.softdep=pre: crc32c ext4.license=GPL ext4.description=Fourth Extended Filesystem ext4.author=Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others ext4.alias=fs-ext4 ext4.alias=ext3 ext4.alias=fs-ext3 ext4.alias=ext2 ext4.alias=fs-ext2 md_mod.alias=block-major-9-* md_mod.alias=md md_mod.description=MD RAID framework md_mod.license=GPL md_mod.parmtype=create_on_open:bool md_mod.parmtype=start_dirty_degraded:int ... Signed-off-by: Alexey Gladkov <gladkov.alexey@xxxxxxxxx> --- Makefile.am | 1 + libkmod/libkmod-builtin.c | 231 +++++++++++++++++++++++++++++++++++++ libkmod/libkmod-internal.h | 8 ++ 3 files changed, 240 insertions(+) create mode 100644 libkmod/libkmod-builtin.c diff --git a/Makefile.am b/Makefile.am index c5c2f06..176dcfc 100644 --- a/Makefile.am +++ b/Makefile.am @@ -68,6 +68,7 @@ libkmod_libkmod_la_SOURCES = \ libkmod/libkmod.h \ libkmod/libkmod-internal.h \ libkmod/libkmod.c \ + libkmod/libkmod-builtin.c \ libkmod/libkmod-list.c \ libkmod/libkmod-config.c \ libkmod/libkmod-index.c \ diff --git a/libkmod/libkmod-builtin.c b/libkmod/libkmod-builtin.c new file mode 100644 index 0000000..9da0010 --- /dev/null +++ b/libkmod/libkmod-builtin.c @@ -0,0 +1,231 @@ +/* + * libkmod - interface to kernel built-in modules + * + * Copyright (C) 2019 Alexey Gladkov <gladkov.alexey@xxxxxxxxx> + * + * 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, see <http://www.gnu.org/licenses/>. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> + +#include "libkmod.h" +#include "libkmod-internal.h" + +#define MODULES_BUILTIN_MODINFO "modules.builtin.modinfo" + +struct kmod_builtin_iter { + struct kmod_ctx *ctx; + struct kmod_file *file; + off_t pos; + off_t next; +}; + +struct kmod_builtin_iter *kmod_builtin_iter_new(struct kmod_ctx *ctx) +{ + char path[PATH_MAX]; + struct kmod_file *file; + struct kmod_builtin_iter *iter; + const char *dirname = kmod_get_dirname(ctx); + size_t len = strlen(dirname); + + if ((len + 1 + strlen(MODULES_BUILTIN_MODINFO) + 1) >= PATH_MAX) { + errno = ENAMETOOLONG; + return NULL; + } + + snprintf(path, PATH_MAX, "%s/%s", dirname, MODULES_BUILTIN_MODINFO); + + file = kmod_file_open(ctx, path); + if (!file) + return NULL; + + iter = malloc(sizeof(*iter)); + if (!iter) { + kmod_file_unref(file); + errno = ENOMEM; + return NULL; + } + + iter->ctx = ctx; + iter->file = file; + iter->pos = 0; + iter->next = 0; + + return iter; +} + +bool kmod_builtin_iter_next(struct kmod_builtin_iter *iter) +{ + char *mm, *s, *dot; + off_t offset, mmsize; + size_t len, modlen; + char *modname = NULL; + + mm = kmod_file_get_contents(iter->file); + mmsize = kmod_file_get_size(iter->file); + + offset = iter->next; + + while (offset < mmsize) { + s = mm + offset; + + dot = strchr(s, '.'); + if (!dot) + return false; + + len = dot - s; + + if (!modname) { + modname = s; + modlen = len; + } else if (modlen != len || strncmp(modname, s, len)) { + break; + } + + offset += strlen(s) + 1; + } + + if (!modname) + return false; + + iter->next = offset; + + return true; +} + +void kmod_builtin_iter_free(struct kmod_builtin_iter *iter) +{ + kmod_file_unref(iter->file); + free(iter); +} + +int kmod_builtin_iter_get_strings(struct kmod_builtin_iter *iter, + const char **strings) +{ + char *mm = kmod_file_get_contents(iter->file); + off_t pos = iter->pos; + + char *start = NULL; + size_t count = 0; + size_t modlen = 0; + + while (pos < iter->next) { + char *dot = strchr(mm + pos, '.'); + size_t len; + + if (!dot) + return -1; + + len = dot - (mm + pos); + + if (!start) { + start = mm + pos; + modlen = len; + } else if (modlen != len || strncmp(start, mm + pos, len)) { + break; + } + + pos += strlen(mm + pos) + 1; + count++; + } + + *strings = start; + iter->pos = iter->next; + + return count; +} + +/* array will be allocated with strings in a single malloc, just free *array */ +int kmod_builtin_get_modinfo(struct kmod_ctx *ctx, const char *modname, + char ***modinfo) +{ + char *mm, *s, *section, *dot; + off_t n, size, offset, mmoffset, mmsize; + size_t modlen, len; + struct kmod_builtin_iter *iter; + int count = 0; + + iter = kmod_builtin_iter_new(ctx); + + if (!iter) + return -1; + + modlen = strlen(modname); + + mmsize = kmod_file_get_size(iter->file); + mm = kmod_file_get_contents(iter->file); + + section = NULL; + size = 0; + + for (mmoffset = 0; mmoffset < mmsize;) { + s = mm + mmoffset; + dot = strchr(s, '.'); + + if (!dot) { + count = -ENODATA; + goto fail; + } + + len = dot - s; + + if (modlen != len || strncmp(modname, s, len)) { + if (count) + break; + mmoffset += strlen(s) + 1; + continue; + } else if (!count) { + section = s; + } + + len = strlen(dot + 1) + 1; + mmoffset += modlen + 1 + len; + size += len; + + count++; + } + + if (!count) { + count = -ENOSYS; + goto fail; + } + + *modinfo = malloc(size + sizeof(char *) * (count + 1)); + if (!*modinfo) { + count = -errno; + goto fail; + } + + s = (char *)(*modinfo + count + 1); + + n = 0; + mmoffset = 0; + + for (offset = 0; offset < size;) { + len = strlen(section + mmoffset + modlen + 1) + 1; + + strncpy(s + offset, section + mmoffset + modlen + 1, len); + (*modinfo)[n++] = s + offset; + + mmoffset += modlen + 1 + len; + offset += len; + } + +fail: + kmod_builtin_iter_free(iter); + return count; +} diff --git a/libkmod/libkmod-internal.h b/libkmod/libkmod-internal.h index a65ddd1..17ae541 100644 --- a/libkmod/libkmod-internal.h +++ b/libkmod/libkmod-internal.h @@ -193,3 +193,11 @@ struct kmod_signature_info { }; bool kmod_module_signature_info(const struct kmod_file *file, struct kmod_signature_info *sig_info) _must_check_ __attribute__((nonnull(1, 2))); void kmod_module_signature_info_free(struct kmod_signature_info *sig_info) __attribute__((nonnull)); + +/* libkmod-builtin.c */ +struct kmod_builtin_iter; +struct kmod_builtin_iter *kmod_builtin_iter_new(struct kmod_ctx *ctx) __attribute__((nonnull(1))); +void kmod_builtin_iter_free(struct kmod_builtin_iter *iter) __attribute__((nonnull(1))); +bool kmod_builtin_iter_next(struct kmod_builtin_iter *iter) __attribute__((nonnull(1))); +int kmod_builtin_iter_get_strings(struct kmod_builtin_iter *iter, const char **modinfo) __attribute__((nonnull(1, 2))); +int kmod_builtin_get_modinfo(struct kmod_ctx *ctx, const char *modname, char ***modinfo) __attribute__((nonnull(1, 2, 3))); -- 2.21.0
