Adding support to get uprobe_link details through bpf_link_info
interface.
Adding new struct uprobe_multi to struct bpf_link_info to carry
the uprobe_multi link details.
The uprobe_multi.count is passed from user space to denote size
of array fields (offsets/ref_ctr_offsets/cookies). The actual
array size is stored back to uprobe_multi.count (allowing user
to find out the actual array size) and array fields are populated
up to the user passed size.
All the non-array fields (path/count/flags/pid) are always set.
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
include/uapi/linux/bpf.h | 10 +++++
kernel/trace/bpf_trace.c | 68 ++++++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 10 +++++
3 files changed, 88 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0f6cdf52b1da..960cf2914d63 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6556,6 +6556,16 @@ struct bpf_link_info {
__u32 flags;
__u64 missed;
} kprobe_multi;
+ struct {
+ __aligned_u64 path;
+ __aligned_u64 offsets;
+ __aligned_u64 ref_ctr_offsets;
+ __aligned_u64 cookies;
+ __u32 path_max; /* in/out: uprobe_multi path size */
+ __u32 count; /* in/out: uprobe_multi offsets/ref_ctr_offsets/cookies count */
+ __u32 flags;
+ __u32 pid;
+ } uprobe_multi;
struct {
__u32 type; /* enum bpf_perf_event_type */
__u32 :32;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 843b3846d3f8..9f8ad19a1a93 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3042,6 +3042,7 @@ struct bpf_uprobe_multi_link {
u32 cnt;
struct bpf_uprobe *uprobes;
struct task_struct *task;
+ u32 flags;
};
struct bpf_uprobe_multi_run_ctx {
@@ -3081,9 +3082,75 @@ static void bpf_uprobe_multi_link_dealloc(struct bpf_link *link)
kfree(umulti_link);
}
+static int bpf_uprobe_multi_link_fill_link_info(const struct bpf_link *link,
+ struct bpf_link_info *info)
+{
+ u64 __user *uref_ctr_offsets = u64_to_user_ptr(info->uprobe_multi.ref_ctr_offsets);
+ u64 __user *ucookies = u64_to_user_ptr(info->uprobe_multi.cookies);
+ u64 __user *uoffsets = u64_to_user_ptr(info->uprobe_multi.offsets);
+ u64 __user *upath = u64_to_user_ptr(info->uprobe_multi.path);
+ u32 upath_max = info->uprobe_multi.path_max;
+ struct bpf_uprobe_multi_link *umulti_link;
+ u32 ucount = info->uprobe_multi.count;
+ int err = 0, i;
+ char *p, *buf;
+ long left;
+
+ if (!upath ^ !upath_max)
+ return -EINVAL;
+
+ if (!uoffsets ^ !ucount)
+ return -EINVAL;
+
+ umulti_link = container_of(link, struct bpf_uprobe_multi_link, link);
+ info->uprobe_multi.count = umulti_link->cnt;
+ info->uprobe_multi.flags = umulti_link->flags;
+ info->uprobe_multi.pid = umulti_link->task ?
+ task_pid_nr(umulti_link->task) : (u32) -1;
+
+ if (upath) {
+ if (upath_max > PATH_MAX)
+ return -E2BIG;
+ buf = kmalloc(upath_max, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ p = d_path(&umulti_link->path, buf, upath_max);
+ if (IS_ERR(p)) {
+ kfree(buf);
+ return -ENOSPC;
+ }
+ left = copy_to_user(upath, p, buf + upath_max - p);
+ kfree(buf);
+ if (left)
+ return -EFAULT;
+ }
+
+ if (!uoffsets)
+ return 0;
+
+ if (ucount < umulti_link->cnt)
+ err = -ENOSPC;
+ else
+ ucount = umulti_link->cnt;
+
+ for (i = 0; i < ucount; i++) {
+ if (put_user(umulti_link->uprobes[i].offset, uoffsets + i))
+ return -EFAULT;
+ if (uref_ctr_offsets &&
+ put_user(umulti_link->uprobes[i].ref_ctr_offset, uref_ctr_offsets + i))
+ return -EFAULT;
+ if (ucookies &&
+ put_user(umulti_link->uprobes[i].cookie, ucookies + i))
+ return -EFAULT;
+ }
+
+ return err;
+}
+
static const struct bpf_link_ops bpf_uprobe_multi_link_lops = {
.release = bpf_uprobe_multi_link_release,
.dealloc = bpf_uprobe_multi_link_dealloc,
+ .fill_link_info = bpf_uprobe_multi_link_fill_link_info,
};
static int uprobe_prog_run(struct bpf_uprobe *uprobe,
@@ -3272,6 +3339,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
link->uprobes = uprobes;
link->path = path;
link->task = task;
+ link->flags = flags;
bpf_link_init(&link->link, BPF_LINK_TYPE_UPROBE_MULTI,
&bpf_uprobe_multi_link_lops, prog);
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 0f6cdf52b1da..960cf2914d63 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6556,6 +6556,16 @@ struct bpf_link_info {
__u32 flags;
__u64 missed;
} kprobe_multi;
+ struct {
+ __aligned_u64 path;
+ __aligned_u64 offsets;
+ __aligned_u64 ref_ctr_offsets;
+ __aligned_u64 cookies;
+ __u32 path_max; /* in/out: uprobe_multi path size */
+ __u32 count; /* in/out: uprobe_multi offsets/ref_ctr_offsets/cookies count */
+ __u32 flags;
+ __u32 pid;
+ } uprobe_multi;
struct {
__u32 type; /* enum bpf_perf_event_type */
__u32 :32;
--
2.41.0
