On Fri, Oct 11, 2019 at 10:19:53AM +0200, Alexey Gladkov wrote:
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
Apologies, I thought I had replied to this already. Having this
functionality is very welcome, thanks. I have some comments about the
implementation. See below.
...
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/>.
+ */
this remembers me we should convert these headers to spdx
+
+#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);
humn... kmod_file is more target for handling modules. This is only
< 100k and we would access it sequentially. I think we are fine just
using stdio.
+
+ offset = iter->next;
+
+ while (offset < mmsize) {
+ s = mm + offset;
+
+ dot = strchr(s, '.');
+ if (!dot)
+ return false;
wouldn't this fail if in the description of a module/param we have a dot?
I think a more correct approach is to search for \0 and then try to
match the prefix.
Actually, maybe even better to memmem() "\0<module-name>.", first being
an exception.
+
+ 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
