// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2024 Google LLC. */

#include <vmlinux.h>
#include <errno.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>

#include "bpf_misc.h"
#include "bpf_experimental.h"

static char buf[64];

SEC("lsm.s/file_open")
__success
int BPF_PROG(get_task_exe_file_and_put_kfunc_from_current_sleepable)
{
        struct file *acquired;

        acquired = bpf_get_task_exe_file(bpf_get_current_task_btf());
        if (!acquired)
                return 0;

        bpf_put_file(acquired);
        return 0;
}

SEC("lsm/file_open")
__success
int BPF_PROG(get_task_exe_file_and_put_kfunc_from_current_non_sleepable, struct file *file)
{
        struct file *acquired;

        acquired = bpf_get_task_exe_file(bpf_get_current_task_btf());
        if (!acquired)
                return 0;

        bpf_put_file(acquired);
        return 0;
}

SEC("lsm.s/task_alloc")
__success
int BPF_PROG(get_task_exe_file_and_put_kfunc_from_argument,
             struct task_struct *task)
{
        struct file *acquired;

        acquired = bpf_get_task_exe_file(task);
        if (!acquired)
                return 0;

        bpf_put_file(acquired);
        return 0;
}

SEC("lsm.s/inode_getattr")
__success
int BPF_PROG(path_d_path_from_path_argument, struct path *path)
{
        int ret;

        ret = bpf_path_d_path(path, buf, sizeof(buf));
        __sink(ret);
        return 0;
}

SEC("lsm.s/file_open")
__success
int BPF_PROG(path_d_path_from_file_argument, struct file *file)
{
        int ret;
        const struct path *path;

        /* The f_path member is a path which is embedded directly within a
         * file. Therefore, a pointer to such embedded members are still
         * recognized by the BPF verifier as being PTR_TRUSTED as it's
         * essentially PTR_TRUSTED w/ a non-zero fixed offset.
         */
        path = &file->f_path;
        ret = bpf_path_d_path(path, buf, sizeof(buf));
        __sink(ret);
        return 0;
}

SEC("lsm.s/inode_rename")
__success
int BPF_PROG(inode_rename, struct inode *old_dir, struct dentry *old_dentry,
             struct inode *new_dir, struct dentry *new_dentry,
             unsigned int flags)
{
        struct inode *inode = new_dentry->d_inode;
        ino_t ino;

        if (!inode)
                return 0;
        ino = inode->i_ino;
        if (ino == 0)
                return -EACCES;
        return 0;
}

char _license[] SEC("license") = "GPL";