1 files changed, 74 insertions, 0 deletions

diff --git a/kernel/kheaders.c b/kernel/kheaders.c
new file mode 100644
index 000000000000..70ae6052920d
--- /dev/null
+++ b/kernel/kheaders.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Provide kernel headers useful to build tracing programs
+ * such as for running eBPF tracing tools.
+ *
+ * (Borrowed code from kernel/configs.c)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+
+/*
+ * Define kernel_headers_data and kernel_headers_data_end, within which the
+ * compressed kernel headers are stored. The file is first compressed with xz.
+ */
+
+asm (
+"       .pushsection .rodata, \"a\"             \n"
+"       .global kernel_headers_data             \n"
+"kernel_headers_data:                           \n"
+"       .incbin \"kernel/kheaders_data.tar.xz\" \n"
+"       .global kernel_headers_data_end         \n"
+"kernel_headers_data_end:                       \n"
+"       .popsection                             \n"
+);
+
+extern char kernel_headers_data;
+extern char kernel_headers_data_end;
+
+static ssize_t
+ikheaders_read_current(struct file *file, char __user *buf,
+                      size_t len, loff_t *offset)
+{
+        return simple_read_from_buffer(buf, len, offset,
+                                       &kernel_headers_data,
+                                       &kernel_headers_data_end -
+                                       &kernel_headers_data);
+}
+
+static const struct file_operations ikheaders_file_ops = {
+        .read = ikheaders_read_current,
+        .llseek = default_llseek,
+};
+
+static int __init ikheaders_init(void)
+{
+        struct proc_dir_entry *entry;
+
+        /* create the current headers file */
+        entry = proc_create("kheaders.tar.xz", S_IRUGO, NULL,
+                            &ikheaders_file_ops);
+        if (!entry)
+                return -ENOMEM;
+
+        proc_set_size(entry,
+                      &kernel_headers_data_end -
+                      &kernel_headers_data);
+        return 0;
+}
+
+static void __exit ikheaders_cleanup(void)
+{
+        remove_proc_entry("kheaders.tar.xz", NULL);
+}
+
+module_init(ikheaders_init);
+module_exit(ikheaders_cleanup);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Joel Fernandes");
+MODULE_DESCRIPTION("Echo the kernel header artifacts used to build the kernel");