[tip:perf/core] perf trace: Consume the augmented_raw_syscalls payload

[tip-bot for Arnaldo Carvalho de Melo <tipbot@zytor.com>]

Commit-ID:  8195168e877948bb9a943ce11ad3e6ee71014bd5
Gitweb:     https://git.kernel.org/tip/8195168e877948bb9a943ce11ad3e6ee71014bd5
Author:     Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Wed, 5 Jun 2019 10:34:47 -0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 5 Jun 2019 10:52:19 -0300

perf trace: Consume the augmented_raw_syscalls payload

To support the SCA_FILENAME beautifier in more than one syscall arg, as
needed for syscalls such as the rename* family, we need to, after
processing one such arg, bump the augmented pointers so that the next
augmented arg don't reuse data for the previous augmented arguments.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-4e4cmzyjxb3wkonfo1x9a27y@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-trace.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 19f22127f02e..905e57c336b0 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1233,8 +1233,17 @@ static void thread__set_filename_pos(struct thread *thread, const char *bf,
 static size_t syscall_arg__scnprintf_augmented_string(struct syscall_arg *arg, char *bf, size_t size)
 {
 	struct augmented_arg *augmented_arg = arg->augmented.args;
+	size_t printed = scnprintf(bf, size, "\"%.*s\"", augmented_arg->size, augmented_arg->value);
+	/*
+	 * So that the next arg with a payload can consume its augmented arg, i.e. for rename* syscalls
+	 * we would have two strings, each prefixed by its size.
+	 */
+	int consumed = sizeof(*augmented_arg) + augmented_arg->size;
 
-	return scnprintf(bf, size, "\"%.*s\"", augmented_arg->size, augmented_arg->value);
+	arg->augmented.args += consumed;
+	arg->augmented.size -= consumed;
+
+	return printed;
 }
 
 static size_t syscall_arg__scnprintf_filename(char *bf, size_t size,