/* Copyright (c) 2020 Facebook */
#include <linux/fs.h>
+#include <linux/anon_inodes.h>
#include <linux/filter.h>
#include <linux/bpf.h>
struct bpf_iter_target_info *tinfo;
};
+struct bpf_iter_priv_data {
+ struct bpf_iter_target_info *tinfo;
+ struct bpf_prog *prog;
+ u64 session_id;
+ u64 seq_num;
+ bool done_stop;
+ u8 target_private[] __aligned(8);
+};
+
static struct list_head targets = LIST_HEAD_INIT(targets);
static DEFINE_MUTEX(targets_mutex);
/* protect bpf_iter_link changes */
static DEFINE_MUTEX(link_mutex);
+/* incremented on every opened seq_file */
+static atomic64_t session_id;
+
/* bpf_seq_read, a customized and simpler version for bpf iterator.
* no_llseek is assumed for this file.
* The following are differences from seq_read():
return copied;
}
+static int iter_release(struct inode *inode, struct file *file)
+{
+ struct bpf_iter_priv_data *iter_priv;
+ struct seq_file *seq;
+
+ seq = file->private_data;
+ if (!seq)
+ return 0;
+
+ iter_priv = container_of(seq->private, struct bpf_iter_priv_data,
+ target_private);
+
+ if (iter_priv->tinfo->fini_seq_private)
+ iter_priv->tinfo->fini_seq_private(seq->private);
+
+ bpf_prog_put(iter_priv->prog);
+ seq->private = iter_priv;
+
+ return seq_release_private(inode, file);
+}
+
+static const struct file_operations bpf_iter_fops = {
+ .llseek = no_llseek,
+ .read = bpf_seq_read,
+ .release = iter_release,
+};
+
int bpf_iter_reg_target(struct bpf_iter_reg *reg_info)
{
struct bpf_iter_target_info *tinfo;
return bpf_link_settle(&link_primer);
}
+
+static void init_seq_meta(struct bpf_iter_priv_data *priv_data,
+ struct bpf_iter_target_info *tinfo,
+ struct bpf_prog *prog)
+{
+ priv_data->tinfo = tinfo;
+ priv_data->prog = prog;
+ priv_data->session_id = atomic64_inc_return(&session_id);
+ priv_data->seq_num = 0;
+ priv_data->done_stop = false;
+}
+
+static int prepare_seq_file(struct file *file, struct bpf_iter_link *link)
+{
+ struct bpf_iter_priv_data *priv_data;
+ struct bpf_iter_target_info *tinfo;
+ struct bpf_prog *prog;
+ u32 total_priv_dsize;
+ struct seq_file *seq;
+ int err = 0;
+
+ mutex_lock(&link_mutex);
+ prog = link->link.prog;
+ bpf_prog_inc(prog);
+ mutex_unlock(&link_mutex);
+
+ tinfo = link->tinfo;
+ total_priv_dsize = offsetof(struct bpf_iter_priv_data, target_private) +
+ tinfo->seq_priv_size;
+ priv_data = __seq_open_private(file, tinfo->seq_ops, total_priv_dsize);
+ if (!priv_data) {
+ err = -ENOMEM;
+ goto release_prog;
+ }
+
+ if (tinfo->init_seq_private) {
+ err = tinfo->init_seq_private(priv_data->target_private);
+ if (err)
+ goto release_seq_file;
+ }
+
+ init_seq_meta(priv_data, tinfo, prog);
+ seq = file->private_data;
+ seq->private = priv_data->target_private;
+
+ return 0;
+
+release_seq_file:
+ seq_release_private(file->f_inode, file);
+ file->private_data = NULL;
+release_prog:
+ bpf_prog_put(prog);
+ return err;
+}
+
+int bpf_iter_new_fd(struct bpf_link *link)
+{
+ struct file *file;
+ unsigned int flags;
+ int err, fd;
+
+ if (link->ops != &bpf_iter_link_lops)
+ return -EINVAL;
+
+ flags = O_RDONLY | O_CLOEXEC;
+ fd = get_unused_fd_flags(flags);
+ if (fd < 0)
+ return fd;
+
+ file = anon_inode_getfile("bpf_iter", &bpf_iter_fops, NULL, flags);
+ if (IS_ERR(file)) {
+ err = PTR_ERR(file);
+ goto free_fd;
+ }
+
+ err = prepare_seq_file(file,
+ container_of(link, struct bpf_iter_link, link));
+ if (err)
+ goto free_file;
+
+ fd_install(fd, file);
+ return fd;
+
+free_file:
+ fput(file);
+free_fd:
+ put_unused_fd(fd);
+ return err;
+}