From: Alexey Gladkov <gladkov.alexey@gmail.com>
To: linux-modules@vger.kernel.org
Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
Subject: [PATCH v2 1/4] libkmod: Add parser for modules.builtin.modinfo
Date: Fri, 8 Nov 2019 18:25:20 +0100 [thread overview]
Message-ID: <20191108172524.468494-2-gladkov.alexey@gmail.com> (raw)
In-Reply-To: <20191108172524.468494-1-gladkov.alexey@gmail.com>
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@gmail.com>
---
Makefile.am | 1 +
libkmod/libkmod-builtin.c | 329 +++++++++++++++++++++++++++++++++++++
libkmod/libkmod-internal.h | 8 +
3 files changed, 338 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..c7b888a
--- /dev/null
+++ b/libkmod/libkmod-builtin.c
@@ -0,0 +1,329 @@
+/*
+ * libkmod - interface to kernel built-in modules
+ *
+ * Copyright (C) 2019 Alexey Gladkov <gladkov.alexey@gmail.com>
+ *
+ * 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 <sys/types.h>
+#include <sys/stat.h>
+
+#include <unistd.h>
+#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;
+
+ // The file descriptor.
+ int file;
+
+ // The total size in bytes.
+ ssize_t size;
+
+ // The offset of current module.
+ off_t pos;
+
+ // The offset at which the next module is located.
+ off_t next;
+
+ // Number of strings in the current block.
+ ssize_t nstrings;
+
+ // Internal buffer and its size.
+ size_t bufsz;
+ char *buf;
+};
+
+struct kmod_builtin_iter *kmod_builtin_iter_new(struct kmod_ctx *ctx)
+{
+ char path[PATH_MAX];
+ int file, sv_errno;
+ struct stat sb;
+ struct kmod_builtin_iter *iter = NULL;
+ const char *dirname = kmod_get_dirname(ctx);
+ size_t len = strlen(dirname);
+
+ file = -1;
+
+ if ((len + 1 + strlen(MODULES_BUILTIN_MODINFO) + 1) >= PATH_MAX) {
+ sv_errno = ENAMETOOLONG;
+ goto fail;
+ }
+
+ snprintf(path, PATH_MAX, "%s/%s", dirname, MODULES_BUILTIN_MODINFO);
+
+ file = open(path, O_RDONLY|O_CLOEXEC);
+ if (file < 0) {
+ sv_errno = errno;
+ goto fail;
+ }
+
+ if (fstat(file, &sb) < 0) {
+ sv_errno = errno;
+ goto fail;
+ }
+
+ iter = malloc(sizeof(*iter));
+ if (!iter) {
+ sv_errno = ENOMEM;
+ goto fail;
+ }
+
+ iter->ctx = ctx;
+ iter->file = file;
+ iter->size = sb.st_size;
+ iter->nstrings = 0;
+ iter->pos = 0;
+ iter->next = 0;
+ iter->bufsz = 0;
+ iter->buf = NULL;
+
+ return iter;
+fail:
+ if (file >= 0)
+ close(file);
+
+ errno = sv_errno;
+
+ return iter;
+}
+
+void kmod_builtin_iter_free(struct kmod_builtin_iter *iter)
+{
+ close(iter->file);
+ free(iter->buf);
+ free(iter);
+}
+
+static off_t get_string(struct kmod_builtin_iter *iter, off_t offset,
+ char **line, size_t *size)
+{
+ int sv_errno;
+ char *nullp = NULL;
+ size_t linesz = 0;
+
+ while (!nullp) {
+ char buf[BUFSIZ];
+ ssize_t sz;
+ size_t partsz;
+
+ sz = pread(iter->file, buf, BUFSIZ, offset);
+ if (sz < 0) {
+ sv_errno = errno;
+ goto fail;
+ } else if (sz == 0) {
+ offset = 0;
+ break;
+ }
+
+ nullp = memchr(buf, '\0', (size_t) sz);
+ partsz = (size_t)((nullp) ? (nullp - buf) + 1 : sz);
+ offset += (off_t) partsz;
+
+ if (iter->bufsz < linesz + partsz) {
+ iter->bufsz = linesz + partsz;
+ iter->buf = realloc(iter->buf, iter->bufsz);
+
+ if (!iter->buf) {
+ sv_errno = errno;
+ goto fail;
+ }
+ }
+
+ strncpy(iter->buf + linesz, buf, partsz);
+ linesz += partsz;
+ }
+
+ if (linesz) {
+ *line = iter->buf;
+ *size = linesz;
+ }
+
+ return offset;
+fail:
+ errno = sv_errno;
+ return -1;
+}
+
+bool kmod_builtin_iter_next(struct kmod_builtin_iter *iter)
+{
+ char *line, *modname;
+ size_t linesz;
+ off_t pos, offset, modlen;
+
+ modname = NULL;
+
+ iter->nstrings = 0;
+ offset = pos = iter->next;
+
+ while (offset < iter->size) {
+ char *dot;
+ off_t len;
+
+ offset = get_string(iter, pos, &line, &linesz);
+ if (offset <= 0) {
+ if (offset)
+ ERR(iter->ctx, "get_string: %s\n", strerror(errno));
+ pos = iter->size;
+ break;
+ }
+
+ dot = strchr(line, '.');
+ if (!dot) {
+ ERR(iter->ctx, "kmod_builtin_iter_next: unexpected string without modname prefix\n");
+ pos = iter->size;
+ break;
+ }
+
+ len = dot - line;
+
+ if (!modname) {
+ modname = strdup(line);
+ modlen = len;
+ } else if (modlen != len || strncmp(modname, line, len)) {
+ break;
+ }
+
+ iter->nstrings++;
+ pos = offset;
+ }
+
+ iter->pos = iter->next;
+ iter->next = pos;
+
+ free(modname);
+
+ return (iter->pos < iter->size);
+}
+
+bool kmod_builtin_iter_get_modname(struct kmod_builtin_iter *iter,
+ char modname[static PATH_MAX])
+{
+ int sv_errno;
+ char *line, *dot;
+ size_t linesz, len;
+ off_t offset;
+
+ if (iter->pos == iter->size)
+ return false;
+
+ line = NULL;
+
+ offset = get_string(iter, iter->pos, &line, &linesz);
+ if (offset <= 0) {
+ sv_errno = errno;
+ if (offset)
+ ERR(iter->ctx, "get_string: %s\n", strerror(errno));
+ goto fail;
+ }
+
+ dot = strchr(line, '.');
+ if (!dot) {
+ sv_errno = errno;
+ ERR(iter->ctx, "kmod_builtin_iter_get_modname: unexpected string without modname prefix\n");
+ goto fail;
+ }
+
+ len = dot - line;
+
+ if (len > PATH_MAX) {
+ sv_errno = ENAMETOOLONG;
+ goto fail;
+ }
+
+ strncpy(modname, line, len);
+ modname[len] = '\0';
+
+ return true;
+fail:
+ errno = sv_errno;
+ return false;
+}
+
+/* array will be allocated with strings in a single malloc, just free *array */
+ssize_t kmod_builtin_get_modinfo(struct kmod_ctx *ctx, const char *modname,
+ char ***modinfo)
+{
+ ssize_t count = 0;
+ char *s, *line = NULL;
+ size_t i, n, linesz, modlen, size;
+ off_t pos, offset;
+
+ char *name = NULL;
+ char buf[PATH_MAX];
+
+ struct kmod_builtin_iter *iter = kmod_builtin_iter_new(ctx);
+
+ if (!iter)
+ return -1;
+
+ while (!name && kmod_builtin_iter_next(iter)) {
+ if (!kmod_builtin_iter_get_modname(iter, buf)) {
+ count = -errno;
+ goto fail;
+ }
+
+ if (strcmp(modname, buf))
+ continue;
+
+ name = buf;
+ }
+
+ if (!name) {
+ count = -ENOSYS;
+ goto fail;
+ }
+
+ modlen = strlen(modname) + 1;
+ count = iter->nstrings;
+ size = iter->next - iter->pos - (modlen * count);
+
+ *modinfo = malloc(size + sizeof(char *) * (count + 1));
+ if (!*modinfo) {
+ count = -errno;
+ goto fail;
+ }
+
+ s = (char *)(*modinfo + count + 1);
+ i = 0;
+
+ n = 0;
+ offset = pos = iter->pos;
+
+ while (offset < iter->next) {
+ offset = get_string(iter, pos, &line, &linesz);
+ if (offset <= 0) {
+ count = (offset) ? -errno : -EOF;
+ goto fail;
+ }
+
+ strcpy(s + i, line + modlen);
+ (*modinfo)[n++] = s + i;
+ i += linesz - modlen;
+
+ pos = offset;
+ }
+fail:
+ kmod_builtin_iter_free(iter);
+ return count;
+}
diff --git a/libkmod/libkmod-internal.h b/libkmod/libkmod-internal.h
index a65ddd1..df01df1 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)));
+bool kmod_builtin_iter_get_modname(struct kmod_builtin_iter *iter, char modname[static PATH_MAX]) __attribute__((nonnull(1, 2)));
+ssize_t kmod_builtin_get_modinfo(struct kmod_ctx *ctx, const char *modname, char ***modinfo) __attribute__((nonnull(1, 2, 3)));
--
2.21.0
next prev parent reply other threads:[~2019-11-08 17:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-08 17:25 [PATCH v2 0/4] Add modules.builtin.modinfo support Alexey Gladkov
2019-11-08 17:25 ` Alexey Gladkov [this message]
2019-11-08 17:25 ` [PATCH v2 2/4] libkmod: Add function to get list of built-in modules Alexey Gladkov
2019-11-08 17:25 ` [PATCH v2 3/4] Lookup aliases in the modules.builtin.modinfo Alexey Gladkov
2019-11-08 17:25 ` [PATCH v2 4/4] modinfo: Show information about built-in modules Alexey Gladkov
2019-11-18 23:17 ` [PATCH v2 0/4] Add modules.builtin.modinfo support Alexey Gladkov
2019-12-04 15:27 ` Alexey Gladkov
2019-12-20 18:45 ` Lucas De Marchi
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