linux/kernel/kheaders.c
Joel Fernandes (Google) f7b101d330 kheaders: Move from proc to sysfs
The kheaders archive consisting of the kernel headers used for compiling
bpf programs is in /proc. However there is concern that moving it here
will make it permanent. Let us move it to /sys/kernel as discussed [1].

[1] https://lore.kernel.org/patchwork/patch/1067310/#1265969

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 20:16:01 +02:00

67 lines
1.6 KiB
C

// 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/kobject.h>
#include <linux/init.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(struct file *file, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t len)
{
memcpy(buf, &kernel_headers_data + off, len);
return len;
}
static struct bin_attribute kheaders_attr __ro_after_init = {
.attr = {
.name = "kheaders.tar.xz",
.mode = 0444,
},
.read = &ikheaders_read,
};
static int __init ikheaders_init(void)
{
kheaders_attr.size = (&kernel_headers_data_end -
&kernel_headers_data);
return sysfs_create_bin_file(kernel_kobj, &kheaders_attr);
}
static void __exit ikheaders_cleanup(void)
{
sysfs_remove_bin_file(kernel_kobj, &kheaders_attr);
}
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");