libbpf: Constify all high-level program attach APIs

Attach APIs shouldn't need to modify bpf_program/bpf_map structs, so
change all struct bpf_program and struct bpf_map pointers to const
pointers. This is completely backwards compatible with no functional
change.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210916015836.1248906-8-andrii@kernel.org

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6aeeb0e..da65a16 100644 (file)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -220,7 +220,7 @@ struct reloc_desc {
 
 struct bpf_sec_def;
 
-typedef struct bpf_link *(*attach_fn_t)(struct bpf_program *prog);
+typedef struct bpf_link *(*attach_fn_t)(const struct bpf_program *prog);
 
 struct bpf_sec_def {
        const char *sec;
@@ -7947,12 +7947,12 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
        __VA_ARGS__                                                         \
 }
 
-static struct bpf_link *attach_kprobe(struct bpf_program *prog);
-static struct bpf_link *attach_tp(struct bpf_program *prog);
-static struct bpf_link *attach_raw_tp(struct bpf_program *prog);
-static struct bpf_link *attach_trace(struct bpf_program *prog);
-static struct bpf_link *attach_lsm(struct bpf_program *prog);
-static struct bpf_link *attach_iter(struct bpf_program *prog);
+static struct bpf_link *attach_kprobe(const struct bpf_program *prog);
+static struct bpf_link *attach_tp(const struct bpf_program *prog);
+static struct bpf_link *attach_raw_tp(const struct bpf_program *prog);
+static struct bpf_link *attach_trace(const struct bpf_program *prog);
+static struct bpf_link *attach_lsm(const struct bpf_program *prog);
+static struct bpf_link *attach_iter(const struct bpf_program *prog);
 
 static const struct bpf_sec_def section_defs[] = {
        BPF_PROG_SEC("socket",                  BPF_PROG_TYPE_SOCKET_FILTER),
@@ -9092,7 +9092,7 @@ static void bpf_link_perf_dealloc(struct bpf_link *link)
        free(perf_link);
 }
 
-struct bpf_link *bpf_program__attach_perf_event_opts(struct bpf_program *prog, int pfd,
+struct bpf_link *bpf_program__attach_perf_event_opts(const struct bpf_program *prog, int pfd,
                                                     const struct bpf_perf_event_opts *opts)
 {
        char errmsg[STRERR_BUFSIZE];
@@ -9167,7 +9167,7 @@ err_out:
        return libbpf_err_ptr(err);
 }
 
-struct bpf_link *bpf_program__attach_perf_event(struct bpf_program *prog, int pfd)
+struct bpf_link *bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd)
 {
        return bpf_program__attach_perf_event_opts(prog, pfd, NULL);
 }
@@ -9332,7 +9332,7 @@ static int perf_event_kprobe_open_legacy(bool retprobe, const char *name, uint64
 }
 
 struct bpf_link *
-bpf_program__attach_kprobe_opts(struct bpf_program *prog,
+bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
                                const char *func_name,
                                const struct bpf_kprobe_opts *opts)
 {
@@ -9389,7 +9389,7 @@ bpf_program__attach_kprobe_opts(struct bpf_program *prog,
        return link;
 }
 
-struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
+struct bpf_link *bpf_program__attach_kprobe(const struct bpf_program *prog,
                                            bool retprobe,
                                            const char *func_name)
 {
@@ -9400,7 +9400,7 @@ struct bpf_link *bpf_program__attach_kprobe(struct bpf_program *prog,
        return bpf_program__attach_kprobe_opts(prog, func_name, &opts);
 }
 
-static struct bpf_link *attach_kprobe(struct bpf_program *prog)
+static struct bpf_link *attach_kprobe(const struct bpf_program *prog)
 {
        DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts);
        unsigned long offset = 0;
@@ -9432,7 +9432,7 @@ static struct bpf_link *attach_kprobe(struct bpf_program *prog)
 }
 
 LIBBPF_API struct bpf_link *
-bpf_program__attach_uprobe_opts(struct bpf_program *prog, pid_t pid,
+bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
                                const char *binary_path, size_t func_offset,
                                const struct bpf_uprobe_opts *opts)
 {
@@ -9472,7 +9472,7 @@ bpf_program__attach_uprobe_opts(struct bpf_program *prog, pid_t pid,
        return link;
 }
 
-struct bpf_link *bpf_program__attach_uprobe(struct bpf_program *prog,
+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)
@@ -9532,7 +9532,7 @@ static int perf_event_open_tracepoint(const char *tp_category,
        return pfd;
 }
 
-struct bpf_link *bpf_program__attach_tracepoint_opts(struct bpf_program *prog,
+struct bpf_link *bpf_program__attach_tracepoint_opts(const struct bpf_program *prog,
                                                     const char *tp_category,
                                                     const char *tp_name,
                                                     const struct bpf_tracepoint_opts *opts)
@@ -9566,14 +9566,14 @@ struct bpf_link *bpf_program__attach_tracepoint_opts(struct bpf_program *prog,
        return link;
 }
 
-struct bpf_link *bpf_program__attach_tracepoint(struct bpf_program *prog,
+struct bpf_link *bpf_program__attach_tracepoint(const struct bpf_program *prog,
                                                const char *tp_category,
                                                const char *tp_name)
 {
        return bpf_program__attach_tracepoint_opts(prog, tp_category, tp_name, NULL);
 }
 
-static struct bpf_link *attach_tp(struct bpf_program *prog)
+static struct bpf_link *attach_tp(const struct bpf_program *prog)
 {
        char *sec_name, *tp_cat, *tp_name;
        struct bpf_link *link;
@@ -9597,7 +9597,7 @@ static struct bpf_link *attach_tp(struct bpf_program *prog)
        return link;
 }
 
-struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
+struct bpf_link *bpf_program__attach_raw_tracepoint(const struct bpf_program *prog,
                                                    const char *tp_name)
 {
        char errmsg[STRERR_BUFSIZE];
@@ -9627,7 +9627,7 @@ struct bpf_link *bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
        return link;
 }
 
-static struct bpf_link *attach_raw_tp(struct bpf_program *prog)
+static struct bpf_link *attach_raw_tp(const struct bpf_program *prog)
 {
        const char *tp_name = prog->sec_name + prog->sec_def->len;
 
@@ -9635,7 +9635,7 @@ static struct bpf_link *attach_raw_tp(struct bpf_program *prog)
 }
 
 /* Common logic for all BPF program types that attach to a btf_id */
-static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog)
+static struct bpf_link *bpf_program__attach_btf_id(const struct bpf_program *prog)
 {
        char errmsg[STRERR_BUFSIZE];
        struct bpf_link *link;
@@ -9664,28 +9664,28 @@ static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog)
        return (struct bpf_link *)link;
 }
 
-struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
+struct bpf_link *bpf_program__attach_trace(const struct bpf_program *prog)
 {
        return bpf_program__attach_btf_id(prog);
 }
 
-struct bpf_link *bpf_program__attach_lsm(struct bpf_program *prog)
+struct bpf_link *bpf_program__attach_lsm(const struct bpf_program *prog)
 {
        return bpf_program__attach_btf_id(prog);
 }
 
-static struct bpf_link *attach_trace(struct bpf_program *prog)
+static struct bpf_link *attach_trace(const struct bpf_program *prog)
 {
        return bpf_program__attach_trace(prog);
 }
 
-static struct bpf_link *attach_lsm(struct bpf_program *prog)
+static struct bpf_link *attach_lsm(const struct bpf_program *prog)
 {
        return bpf_program__attach_lsm(prog);
 }
 
 static struct bpf_link *
-bpf_program__attach_fd(struct bpf_program *prog, int target_fd, int btf_id,
+bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id,
                       const char *target_name)
 {
        DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts,
@@ -9721,24 +9721,24 @@ bpf_program__attach_fd(struct bpf_program *prog, int target_fd, int btf_id,
 }
 
 struct bpf_link *
-bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd)
+bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd)
 {
        return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup");
 }
 
 struct bpf_link *
-bpf_program__attach_netns(struct bpf_program *prog, int netns_fd)
+bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd)
 {
        return bpf_program__attach_fd(prog, netns_fd, 0, "netns");
 }
 
-struct bpf_link *bpf_program__attach_xdp(struct bpf_program *prog, int ifindex)
+struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex)
 {
        /* target_fd/target_ifindex use the same field in LINK_CREATE */
        return bpf_program__attach_fd(prog, ifindex, 0, "xdp");
 }
 
-struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog,
+struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog,
                                              int target_fd,
                                              const char *attach_func_name)
 {
@@ -9771,7 +9771,7 @@ struct bpf_link *bpf_program__attach_freplace(struct bpf_program *prog,
 }
 
 struct bpf_link *
-bpf_program__attach_iter(struct bpf_program *prog,
+bpf_program__attach_iter(const struct bpf_program *prog,
                         const struct bpf_iter_attach_opts *opts)
 {
        DECLARE_LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);
@@ -9810,12 +9810,12 @@ bpf_program__attach_iter(struct bpf_program *prog,
        return link;
 }
 
-static struct bpf_link *attach_iter(struct bpf_program *prog)
+static struct bpf_link *attach_iter(const struct bpf_program *prog)
 {
        return bpf_program__attach_iter(prog, NULL);
 }
 
-struct bpf_link *bpf_program__attach(struct bpf_program *prog)
+struct bpf_link *bpf_program__attach(const struct bpf_program *prog)
 {
        if (!prog->sec_def || !prog->sec_def->attach_fn)
                return libbpf_err_ptr(-ESRCH);
@@ -9833,7 +9833,7 @@ static int bpf_link__detach_struct_ops(struct bpf_link *link)
        return 0;
 }
 
-struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map)
+struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map)
 {
        struct bpf_struct_ops *st_ops;
        struct bpf_link *link;
@@ -10918,7 +10918,7 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
                if (!prog->sec_def || !prog->sec_def->attach_fn)
                        continue;
 
-               *link = prog->sec_def->attach_fn(prog);
+               *link = bpf_program__attach(prog);
                err = libbpf_get_error(*link);
                if (err) {
                        pr_warn("failed to auto-attach program '%s': %d\n",

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 52b7ee0..c90e3d7 100644 (file)
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -246,7 +246,7 @@ LIBBPF_API int bpf_link__detach(struct bpf_link *link);
 LIBBPF_API int bpf_link__destroy(struct bpf_link *link);
 
 LIBBPF_API struct bpf_link *
-bpf_program__attach(struct bpf_program *prog);
+bpf_program__attach(const struct bpf_program *prog);
 
 struct bpf_perf_event_opts {
        /* size of this struct, for forward/backward compatiblity */
@@ -257,10 +257,10 @@ struct bpf_perf_event_opts {
 #define bpf_perf_event_opts__last_field bpf_cookie
 
 LIBBPF_API struct bpf_link *
-bpf_program__attach_perf_event(struct bpf_program *prog, int pfd);
+bpf_program__attach_perf_event(const struct bpf_program *prog, int pfd);
 
 LIBBPF_API struct bpf_link *
-bpf_program__attach_perf_event_opts(struct bpf_program *prog, int pfd,
+bpf_program__attach_perf_event_opts(const struct bpf_program *prog, int pfd,
                                    const struct bpf_perf_event_opts *opts);
 
 struct bpf_kprobe_opts {
@@ -277,10 +277,10 @@ struct bpf_kprobe_opts {
 #define bpf_kprobe_opts__last_field retprobe
 
 LIBBPF_API struct bpf_link *
-bpf_program__attach_kprobe(struct bpf_program *prog, bool retprobe,
+bpf_program__attach_kprobe(const struct bpf_program *prog, bool retprobe,
                           const char *func_name);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_kprobe_opts(struct bpf_program *prog,
+bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
                                 const char *func_name,
                                 const struct bpf_kprobe_opts *opts);
 
@@ -300,11 +300,11 @@ struct bpf_uprobe_opts {
 #define bpf_uprobe_opts__last_field retprobe
 
 LIBBPF_API struct bpf_link *
-bpf_program__attach_uprobe(struct bpf_program *prog, bool retprobe,
+bpf_program__attach_uprobe(const struct bpf_program *prog, bool retprobe,
                           pid_t pid, const char *binary_path,
                           size_t func_offset);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_uprobe_opts(struct bpf_program *prog, pid_t pid,
+bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
                                const char *binary_path, size_t func_offset,
                                const struct bpf_uprobe_opts *opts);
 
@@ -317,35 +317,35 @@ struct bpf_tracepoint_opts {
 #define bpf_tracepoint_opts__last_field bpf_cookie
 
 LIBBPF_API struct bpf_link *
-bpf_program__attach_tracepoint(struct bpf_program *prog,
+bpf_program__attach_tracepoint(const struct bpf_program *prog,
                               const char *tp_category,
                               const char *tp_name);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_tracepoint_opts(struct bpf_program *prog,
+bpf_program__attach_tracepoint_opts(const struct bpf_program *prog,
                                    const char *tp_category,
                                    const char *tp_name,
                                    const struct bpf_tracepoint_opts *opts);
 
 LIBBPF_API struct bpf_link *
-bpf_program__attach_raw_tracepoint(struct bpf_program *prog,
+bpf_program__attach_raw_tracepoint(const struct bpf_program *prog,
                                   const char *tp_name);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_trace(struct bpf_program *prog);
+bpf_program__attach_trace(const struct bpf_program *prog);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_lsm(struct bpf_program *prog);
+bpf_program__attach_lsm(const struct bpf_program *prog);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_cgroup(struct bpf_program *prog, int cgroup_fd);
+bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_netns(struct bpf_program *prog, int netns_fd);
+bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_xdp(struct bpf_program *prog, int ifindex);
+bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex);
 LIBBPF_API struct bpf_link *
-bpf_program__attach_freplace(struct bpf_program *prog,
+bpf_program__attach_freplace(const struct bpf_program *prog,
                             int target_fd, const char *attach_func_name);
 
 struct bpf_map;
 
-LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(struct bpf_map *map);
+LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map);
 
 struct bpf_iter_attach_opts {
        size_t sz; /* size of this struct for forward/backward compatibility */
@@ -355,7 +355,7 @@ struct bpf_iter_attach_opts {
 #define bpf_iter_attach_opts__last_field link_info_len
 
 LIBBPF_API struct bpf_link *
-bpf_program__attach_iter(struct bpf_program *prog,
+bpf_program__attach_iter(const struct bpf_program *prog,
                         const struct bpf_iter_attach_opts *opts);
 
 struct bpf_insn;