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[213.175.37.12]) by smtp.gmail.com with ESMTPSA id c3sm14400378edr.33.2022.01.04.00.10.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Jan 2022 00:10:51 -0800 (PST) From: Jiri Olsa X-Google-Original-From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Masami Hiramatsu Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, lkml , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Steven Rostedt , "Naveen N. Rao" , Anil S Keshavamurthy , "David S. Miller" Subject: [PATCH 11/13] libbpf: Add bpf_program__attach_kprobe_opts for multi kprobes Date: Tue, 4 Jan 2022 09:09:41 +0100 Message-Id: <20220104080943.113249-12-jolsa@kernel.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20220104080943.113249-1-jolsa@kernel.org> References: <20220104080943.113249-1-jolsa@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net SEC("raw_kprobe/bpf_fentry_test*") to attach program to all bpf_fentry_test* functions. Signed-off-by: Jiri Olsa --- tools/lib/bpf/libbpf.c | 124 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 123 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 25512b4dbc8c..0061ab02fc5a 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10000,6 +10000,125 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe, return pfd; } +struct kprobe_resolve_raw_kprobe { + const char *name; + __u64 *addrs; + __u32 alloc; + __u32 cnt; +}; + +static bool glob_matches(const char *glob, const char *s) +{ + int n = strlen(glob); + + if (n == 1 && glob[0] == '*') + return true; + + if (glob[0] == '*' && glob[n - 1] == '*') { + const char *subs; + /* substring match */ + + /* this is hacky, but we don't want to allocate + * for no good reason + */ + ((char *)glob)[n - 1] = '\0'; + subs = strstr(s, glob + 1); + ((char *)glob)[n - 1] = '*'; + + return subs != NULL; + } else if (glob[0] == '*') { + size_t nn = strlen(s); + /* suffix match */ + + /* too short for a given suffix */ + if (nn < n - 1) + return false; + return strcmp(s + nn - (n - 1), glob + 1) == 0; + } else if (glob[n - 1] == '*') { + /* prefix match */ + return strncmp(s, glob, n - 1) == 0; + } else { + /* exact match */ + return strcmp(glob, s) == 0; + } +} + +static int +kprobe_resolve_raw_kprobe_cb(void *arg, unsigned long long sym_addr, + char sym_type, const char *sym_name) +{ + struct kprobe_resolve_raw_kprobe *res = arg; + __u64 *p; + + if (!glob_matches(res->name, sym_name)) + return 0; + + if (res->cnt == res->alloc) { + res->alloc = max((__u32) 16, res->alloc * 3 / 2); + p = libbpf_reallocarray(res->addrs, res->alloc, sizeof(__u32)); + if (!p) + return -ENOMEM; + res->addrs = p; + } + res->addrs[res->cnt++] = sym_addr; + return 0; +} + +static struct bpf_link * +attach_raw_kprobe_opts(const struct bpf_program *prog, + const char *func_name, + const struct bpf_kprobe_opts *kopts) +{ + DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts); + struct kprobe_resolve_raw_kprobe res = { + .name = func_name, + }; + struct bpf_link *link = NULL; + char errmsg[STRERR_BUFSIZE]; + int err, link_fd, prog_fd; + __u64 bpf_cookie; + bool retprobe; + + err = libbpf__kallsyms_parse(&res, kprobe_resolve_raw_kprobe_cb); + if (err) + goto error; + if (!res.cnt) { + err = -ENOENT; + goto error; + } + + retprobe = OPTS_GET(kopts, retprobe, false); + bpf_cookie = OPTS_GET(kopts, bpf_cookie, 0); + + opts.kprobe.addrs = (__u64) res.addrs; + opts.kprobe.cnt = res.cnt; + opts.kprobe.bpf_cookie = bpf_cookie; + opts.flags = retprobe ? BPF_F_KPROBE_RETURN : 0; + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_err_ptr(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + prog_fd = bpf_program__fd(prog); + link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_RAW_KPROBE, &opts); + if (link_fd < 0) { + err = -errno; + pr_warn("prog '%s': failed to attach to %s: %s\n", + prog->name, res.name, + libbpf_strerror_r(err, errmsg, sizeof(errmsg))); + goto error; + } + link->fd = link_fd; + free(res.addrs); + return link; + +error: + free(link); + free(res.addrs); + return libbpf_err_ptr(err); +} + struct bpf_link * bpf_program__attach_kprobe_opts(const struct bpf_program *prog, const char *func_name, @@ -10016,6 +10135,9 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog, if (!OPTS_VALID(opts, bpf_kprobe_opts)) return libbpf_err_ptr(-EINVAL); + if (strchr(func_name, '*')) + return attach_raw_kprobe_opts(prog, func_name, opts); + retprobe = OPTS_GET(opts, retprobe, false); offset = OPTS_GET(opts, offset, 0); pe_opts.bpf_cookie = OPTS_GET(opts, bpf_cookie, 0); @@ -10096,7 +10218,7 @@ static struct bpf_link *attach_kprobe(const struct bpf_program *prog, long cooki else func_name = prog->sec_name + sizeof("kprobe/") - 1; - n = sscanf(func_name, "%m[a-zA-Z0-9_.]+%li", &func, &offset); + n = sscanf(func_name, "%m[a-zA-Z0-9_.*]+%li", &func, &offset); if (n < 1) { err = -EINVAL; pr_warn("kprobe name is invalid: %s\n", func_name);