[RFC PATCH v3 29/37] perf bpf: Add 'perf bpf record' subcommand

Wang Nan
2015-05-17T11:00:11Z

'perf bpf record' will be implemented to load eBPF object file then
start recording on events defined in it. This patch only adds a
'--object' option for selecting object file. Other arguments are
directly passed to cmd_record.

Example:

# perf bpf --object obj1.o --object obj2.o -- -a command-to-record

Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
tools/perf/builtin-bpf.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 109 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-bpf.c b/tools/perf/builtin-bpf.c
index a8858e2..b5c613f 100644
--- a/tools/perf/builtin-bpf.c
+++ b/tools/perf/builtin-bpf.c
@@ -48,14 +48,121 @@ static void print_usage(void)
exit(129);
}

-static const char * const bpf_subcommands[] = { NULL };
+static const char * const bpf_record_usage[] = {
+ "perf bpf record [<options>] -- [options passed to record]",
+ NULL
+};
+
+struct param {
+ struct strlist *object_file_names;
+} param;
+
+static int add_bpf_object_file(const struct option *opt,
+ const char *str,
+ int unset __maybe_unused)
+{
+ struct strlist **filenames = (struct strlist **)opt->value;
+
+ if (!*filenames)
+ *filenames = strlist__new(true, NULL);
+
+ if (!*filenames) {
+ pr_err("alloc strlist failed\n");
+ return -ENOMEM;
+ }
+
+ strlist__add(*filenames, str);
+ return 0;
+}
+
+static int start_bpf_record(int argc, const char **argv)
+{
+ int i, new_argc, err, pos = 0;
+ const char **new_argv;
+
+ new_argc = argc + 1;
+ new_argv = malloc((new_argc + 1) * sizeof(const char *));
+ if (!new_argv) {
+ pr_err("malloc failed\n");
+ return -ENOMEM;
+ }
+ bzero(new_argv, sizeof(const char *) * (new_argc + 1));
+
+ new_argv[pos++] = strdup("bpf record --");
+
+ for (i = 0; i < argc; i++) {
+ new_argv[pos++] = strdup(argv[i]);
+ if (!new_argv[pos - 1]) {
+ pr_err("strdup failed\n");
+ err = -ENOMEM;
+ goto errout;
+ }
+ }
+
+ return cmd_record(new_argc, new_argv, NULL);
+
+errout:
+ if (new_argv) {
+ for (i = 0; i < pos; i++)
+ free((void *)new_argv[i]);
+ free(new_argv);
+ }
+ return err;
+}
+
+static int cmd_bpf_record(int argc, const char **argv,
+ const char *prefix __maybe_unused)
+{
+ /*
+ * Options in perf-record may be mirrored here. This command
+ * should add '-e' options to cmd_record.
+ */
+ static const struct option options[] = {
+ OPT_CALLBACK(0, "object", &param.object_file_names,
+ "file", "eBPF object file name",
+ add_bpf_object_file),
+ OPT_END()
+ };
+ struct str_node *str_node;
+
+ argc = parse_options(argc, argv, options,
+ bpf_record_usage, PARSE_OPT_KEEP_DASHDASH);
+
+ if (!param.object_file_names) {
+ pr_err("At least one '--object' option is needed to "
+ "select an eBPF object file\n");
+ goto usage;
+ }
+
+ if (!argv || strcmp(argv[0], "--")) {
+ pr_err("Should use '--' to pass options to perf "
+ "record\n");
+ goto usage;
+ }
+
+ /* skip "--" */
+ argc--;
+ argv++;
+
+ strlist__for_each(str_node, param.object_file_names)
+ pr_debug("loading %s\n", str_node->s);
+
+ return start_bpf_record(argc, argv);
+usage:
+ usage_with_options(bpf_record_usage, options);
+ return -1;
+}
+
+
+static const char * const bpf_subcommands[] = { "record", NULL };

static struct bpf_cmd bpf_cmds[] = {
+ { "record", "load eBPF program into kernel then start record on events in it", cmd_bpf_record },
{ .name = NULL, },
};

int cmd_bpf(int argc, const char **argv,
- const char *prefix __maybe_unused)
+ const char *prefix)
{
struct bpf_cmd *cmd;
const char *cmdstr;
--
1.8.3.4