From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Stringer Subject: [PATCHv3 perf/core 1/6] tools lib bpf: Add BPF program pinning APIs. Date: Thu, 26 Jan 2017 13:19:56 -0800 Message-ID: <20170126212001.14103-2-joe@ovn.org> References: <20170126212001.14103-1-joe@ovn.org> Cc: wangnan0@huawei.com, ast@fb.com, daniel@iogearbox.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: acme@kernel.org Return-path: In-Reply-To: <20170126212001.14103-1-joe@ovn.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Add new APIs to pin a BPF program (or specific instances) to the filesystem. The user can specify the path full path within a BPF filesystem to pin the program. bpf_program__pin_instance(prog, path, n) will pin the nth instance of 'prog' to the specified path. bpf_program__pin(prog, path) will create the directory 'path' (if it does not exist) and pin each instance within that directory. For instance, path/0, path/1, path/2. Signed-off-by: Joe Stringer --- v3: Add per-instance pinning. Use path for bpf_program__pin() as directory. v2: Don't automount BPF filesystem Split program, map, object pinning into separate APIs and separate patches. --- tools/lib/bpf/libbpf.c | 112 +++++++++++++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 3 ++ 2 files changed, 115 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e6cd62b1264b..d1d7638b7c21 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4,6 +4,7 @@ * Copyright (C) 2013-2015 Alexei Starovoitov * Copyright (C) 2015 Wang Nan * Copyright (C) 2015 Huawei Inc. + * Copyright (C) 2017 Nicira, Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -22,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -31,7 +33,10 @@ #include #include #include +#include #include +#include +#include #include #include @@ -1237,6 +1242,113 @@ int bpf_object__load(struct bpf_object *obj) return err; } +static int check_path(const char *path) +{ + struct statfs st_fs; + char *dname, *dir; + int err = 0; + + if (path == NULL) + return -EINVAL; + + dname = strdup(path); + dir = dirname(dname); + if (statfs(dir, &st_fs)) { + pr_warning("failed to statfs %s: %s\n", dir, strerror(errno)); + err = -errno; + } + free(dname); + + if (!err && st_fs.f_type != BPF_FS_MAGIC) { + pr_warning("specified path %s is not on BPF FS\n", path); + err = -EINVAL; + } + + return err; +} + +int bpf_program__pin_instance(struct bpf_program *prog, const char *path, + int instance) +{ + int err; + + err = check_path(path); + if (err) + return err; + + if (prog == NULL) { + pr_warning("invalid program pointer\n"); + return -EINVAL; + } + + if (instance < 0 || instance >= prog->instances.nr) { + pr_warning("invalid prog instance %d of prog %s (max %d)\n", + instance, prog->section_name, prog->instances.nr); + return -EINVAL; + } + + if (bpf_obj_pin(prog->instances.fds[instance], path)) { + pr_warning("failed to pin program: %s\n", strerror(errno)); + return -errno; + } + pr_debug("pinned program '%s'\n", path); + + return 0; +} + +static int make_dir(const char *path) +{ + int err = 0; + + if (mkdir(path, 0700) && errno != EEXIST) + err = -errno; + + if (err) + pr_warning("failed to mkdir %s: %s\n", path, strerror(-err)); + return err; +} + +int bpf_program__pin(struct bpf_program *prog, const char *path) +{ + int i, err; + + err = check_path(path); + if (err) + return err; + + if (prog == NULL) { + pr_warning("invalid program pointer\n"); + return -EINVAL; + } + + if (prog->instances.nr <= 0) { + pr_warning("no instances of prog %s to pin\n", + prog->section_name); + return -EINVAL; + } + + err = make_dir(path); + if (err) + return err; + + for (i = 0; i < prog->instances.nr; i++) { + char buf[PATH_MAX]; + int len; + + len = snprintf(buf, PATH_MAX, "%s/%d", path, i); + if (len < 0) + return -EINVAL; + else if (len > PATH_MAX) + return -ENAMETOOLONG; + + err = bpf_program__pin_instance(prog, buf, i); + if (err) + return err; + } + + return 0; +} + void bpf_object__close(struct bpf_object *obj) { size_t i; diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 4014d1ba5e3d..9f8aa63b95f4 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -106,6 +106,9 @@ void *bpf_program__priv(struct bpf_program *prog); const char *bpf_program__title(struct bpf_program *prog, bool needs_copy); int bpf_program__fd(struct bpf_program *prog); +int bpf_program__pin_instance(struct bpf_program *prog, const char *path, + int instance); +int bpf_program__pin(struct bpf_program *prog, const char *path); struct bpf_insn; -- 2.11.0