Thread (4 messages) 4 messages, 3 authors, 2021-12-06

Re: [PATCH bpf-next] libbpf: Add doc comments in libb.h

From: Song Liu <song@kernel.org>
Date: 2021-11-27 21:30:43

On Sat, Nov 27, 2021 at 1:04 PM grantseltzer [off-list ref] wrote:
From: Grant Seltzer <redacted>

This adds comments above functions in libbpf.h which document
their uses. These comments are of a format that doxygen and sphinx
can pick up and render. These are rendered by libbpf.readthedocs.org

These doc comments are for:

- bpf_object__open_file()
- bpf_object__open_mem()
- bpf_program__attach_uprobe()
- bpf_program__attach_uprobe_opts()

Signed-off-by: Grant Seltzer <redacted>
s/libb.h/libbpf.h/ in subject
quoted hunk ↗ jump to hunk
---
 tools/lib/bpf/libbpf.h | 45 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 4ec69f224342..acfb207e71d1 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -108,8 +108,26 @@ struct bpf_object_open_opts {
 #define bpf_object_open_opts__last_field btf_custom_path

 LIBBPF_API struct bpf_object *bpf_object__open(const char *path);
+
+/**
+ * @brief **bpf_object__open_file()** creates a bpf_object by opening
+ * the BPF object file pointed to by the passed path and loading it
+ * into memory.
+ * @param path BPF object file relative or absolute path
+ * @param opts options for how to load the bpf object
+ * @return pointer to the new bpf_object
Please document return value on errors, i.e. libbpf_err_ptr(err)
instead of NULL. Same for all functions here.
quoted hunk ↗ jump to hunk
+ */
 LIBBPF_API struct bpf_object *
 bpf_object__open_file(const char *path, const struct bpf_object_open_opts *opts);
+
+/**
+ * @brief **bpf_object__open_mem()** creates a bpf_object by reading
+ * the BPF objects raw bytes from an in memory buffer.
+ * @param obj_buf pointer to the buffer containing bpf object bytes
+ * @param obj_buf_sz number of bytes in the buffer
+ * @param opts options for how to load the bpf object
+ * @return pointer to the new bpf_object
+ */
 LIBBPF_API struct bpf_object *
 bpf_object__open_mem(const void *obj_buf, size_t obj_buf_sz,
                     const struct bpf_object_open_opts *opts);
@@ -344,10 +362,37 @@ struct bpf_uprobe_opts {
 };
 #define bpf_uprobe_opts__last_field retprobe

+/**
+ * @brief **bpf_program__attach_uprobe** attaches a BPF program
+ * to the userspace function which is found by binary path and
+ * offset. You can optionally specify a particular proccess to attach
s/proccess/process/
+ * to. You can also optionally attach the program to the function
+ * exit instead of entry.
+ *
+ * @param prog BPF program to attach
+ * @param retprobe Attach to function exit
+ * @param pid Process ID to attach the uprobe to, -1 for all processes
+ * @param binary_path Path to binary that contains the function symbol
+ * @param func_offset Offset within the binary of the function symbol
+ * @return Reference to the newly created BPF link
+ */
 LIBBPF_API struct bpf_link *
 bpf_program__attach_uprobe(const struct bpf_program *prog, bool retprobe,
                           pid_t pid, const char *binary_path,
                           size_t func_offset);
+
+/**
+ * @brief **bpf_program__attach_uprobe_opts** is just like
+ * bpf_program__attach_uprobe except with a options struct
+ * for various configurations.
+ *
+ * @param prog BPF program to attach
+ * @param pid Process ID to attach the uprobe to, -1 for all processes
+ * @param binary_path Path to binary that contains the function symbol
+ * @param func_offset Offset within the binary of the function symbol
+ * @param opts Options for altering program attachment
Let's also document details about these options.
+ * @return Reference to the newly created BPF link
+ */
 LIBBPF_API struct bpf_link *
 bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
                                const char *binary_path, size_t func_offset,
--
2.31.1
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