From 361f2b1d1d7231b8685d990b886f599378a4d5a5 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Mon, 16 Nov 2015 12:10:05 +0000 Subject: [PATCH] perf bpf: Allow BPF program attach to uprobe events This patch adds a new syntax to the BPF object section name to support probing at uprobe event. Now we can use BPF program like this: SEC( "exec=/lib64/libc.so.6;" "libcwrite=__write" ) int libcwrite(void *ctx) { return 1; } Where, in section name of a program, before the main config string, we can use 'key=value' style options. Now the only option key is "exec", for uprobes. Signed-off-by: Wang Nan Cc: Alexei Starovoitov Cc: Masami Hiramatsu Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-4-git-send-email-wangnan0@huawei.com [ Changed the separator from \n to ; ] Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/bpf-loader.c | 120 +++++++++++++++++++++++++++++++++-- tools/perf/util/bpf-loader.h | 1 + 2 files changed, 115 insertions(+), 6 deletions(-) diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 4c50411371db..84169d6f2585 100644 --- a/tools/perf/util/bpf-loader.c +++ b/tools/perf/util/bpf-loader.c @@ -109,6 +109,113 @@ bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused, free(priv); } +static int +config__exec(const char *value, struct perf_probe_event *pev) +{ + pev->uprobes = true; + pev->target = strdup(value); + if (!pev->target) + return -ENOMEM; + return 0; +} + +static struct { + const char *key; + const char *usage; + const char *desc; + int (*func)(const char *, struct perf_probe_event *); +} bpf_config_terms[] = { + { + .key = "exec", + .usage = "exec=", + .desc = "Set uprobe target", + .func = config__exec, + }, +}; + +static int +do_config(const char *key, const char *value, + struct perf_probe_event *pev) +{ + unsigned int i; + + pr_debug("config bpf program: %s=%s\n", key, value); + for (i = 0; i < ARRAY_SIZE(bpf_config_terms); i++) + if (strcmp(key, bpf_config_terms[i].key) == 0) + return bpf_config_terms[i].func(value, pev); + + pr_debug("BPF: ERROR: invalid config option in object: %s=%s\n", + key, value); + + pr_debug("\nHint: Currently valid options are:\n"); + for (i = 0; i < ARRAY_SIZE(bpf_config_terms); i++) + pr_debug("\t%s:\t%s\n", bpf_config_terms[i].usage, + bpf_config_terms[i].desc); + pr_debug("\n"); + + return -BPF_LOADER_ERRNO__CONFIG_TERM; +} + +static const char * +parse_config_kvpair(const char *config_str, struct perf_probe_event *pev) +{ + char *text = strdup(config_str); + char *sep, *line; + const char *main_str = NULL; + int err = 0; + + if (!text) { + pr_debug("No enough memory: dup config_str failed\n"); + return ERR_PTR(-ENOMEM); + } + + line = text; + while ((sep = strchr(line, ';'))) { + char *equ; + + *sep = '\0'; + equ = strchr(line, '='); + if (!equ) { + pr_warning("WARNING: invalid config in BPF object: %s\n", + line); + pr_warning("\tShould be 'key=value'.\n"); + goto nextline; + } + *equ = '\0'; + + err = do_config(line, equ + 1, pev); + if (err) + break; +nextline: + line = sep + 1; + } + + if (!err) + main_str = config_str + (line - text); + free(text); + + return err ? ERR_PTR(err) : main_str; +} + +static int +parse_config(const char *config_str, struct perf_probe_event *pev) +{ + int err; + const char *main_str = parse_config_kvpair(config_str, pev); + + if (IS_ERR(main_str)) + return PTR_ERR(main_str); + + err = parse_perf_probe_command(main_str, pev); + if (err < 0) { + pr_debug("bpf: '%s' is not a valid config string\n", + config_str); + /* parse failed, don't need clear pev. */ + return -BPF_LOADER_ERRNO__CONFIG; + } + return 0; +} + static int config_bpf_program(struct bpf_program *prog) { @@ -131,13 +238,9 @@ config_bpf_program(struct bpf_program *prog) pev = &priv->pev; pr_debug("bpf: config program '%s'\n", config_str); - err = parse_perf_probe_command(config_str, pev); - if (err < 0) { - pr_debug("bpf: '%s' is not a valid config string\n", - config_str); - err = -BPF_LOADER_ERRNO__CONFIG; + err = parse_config(config_str, pev); + if (err) goto errout; - } if (pev->group && strcmp(pev->group, PERF_BPF_PROBE_GROUP)) { pr_debug("bpf: '%s': group for event is set and not '%s'.\n", @@ -340,6 +443,7 @@ static const char *bpf_loader_strerror_table[NR_ERRNO] = { [ERRCODE_OFFSET(EVENTNAME)] = "No event name found in config string", [ERRCODE_OFFSET(INTERNAL)] = "BPF loader internal error", [ERRCODE_OFFSET(COMPILE)] = "Error when compiling BPF scriptlet", + [ERRCODE_OFFSET(CONFIG_TERM)] = "Invalid config term in config string", }; static int @@ -420,6 +524,10 @@ int bpf__strerror_probe(struct bpf_object *obj __maybe_unused, int err, char *buf, size_t size) { bpf__strerror_head(err, buf, size); + case BPF_LOADER_ERRNO__CONFIG_TERM: { + scnprintf(buf, size, "%s (add -v to see detail)", emsg); + break; + } bpf__strerror_entry(EEXIST, "Probe point exist. Try use 'perf probe -d \"*\"'"); bpf__strerror_entry(EACCES, "You need to be root"); bpf__strerror_entry(EPERM, "You need to be root, and /proc/sys/kernel/kptr_restrict should be 0"); diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h index 9caf3ae4acf3..d19f5c5d6d74 100644 --- a/tools/perf/util/bpf-loader.h +++ b/tools/perf/util/bpf-loader.h @@ -20,6 +20,7 @@ enum bpf_loader_errno { BPF_LOADER_ERRNO__EVENTNAME, /* Event name is missing */ BPF_LOADER_ERRNO__INTERNAL, /* BPF loader internal error */ BPF_LOADER_ERRNO__COMPILE, /* Error when compiling BPF scriptlet */ + BPF_LOADER_ERRNO__CONFIG_TERM, /* Invalid config term in config term */ __BPF_LOADER_ERRNO__END, }; -- 2.20.1