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Message-Id: <1447774291-14532-7-git-send-email-acme@kernel.org>
Date: Tue, 17 Nov 2015 12:31:21 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: linux-kernel@...r.kernel.org, Wang Nan <wangnan0@...wei.com>,
Alexei Starovoitov <ast@...nel.org>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Zefan Li <lizefan@...wei.com>, pi3orama@....com,
Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 06/16] perf bpf: Allow BPF program attach to uprobe events
From: Wang Nan <wangnan0@...wei.com>
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 <wangnan0@...wei.com>
Cc: Alexei Starovoitov <ast@...nel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Zefan Li <lizefan@...wei.com>
Cc: pi3orama@....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 <acme@...hat.com>
---
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
@@ -110,6 +110,113 @@ bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused,
}
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=<full path of file>",
+ .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)
{
struct perf_probe_event *pev = NULL;
@@ -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,
};
--
2.1.0
--
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