perf augmented_raw_syscalls: Move reading filename to the loop

Almost there, next step is to copy more than one filename payload.

Probably to read syscall arg structs, etc we'll need just a variation of
this that will decide what to use, if probe_read_str() or plain
probe_read for structs, i.e. fixed size.

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-uf6u0pld6xe4xuo16f04owlz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/examples/bpf/augmented_raw_syscalls.c b/tools/perf/examples/bpf/augmented_raw_syscalls.c
index 5054b4b..2f822bb 100644 (file)
--- a/tools/perf/examples/bpf/augmented_raw_syscalls.c
+++ b/tools/perf/examples/bpf/augmented_raw_syscalls.c
@@ -102,8 +102,6 @@ int sys_enter(struct syscall_enter_args *args)
         * initial, non-augmented raw_syscalls:sys_enter payload.
         */
        unsigned int len = sizeof(augmented_args->args);
-       unsigned int filename_len;
-       const void *filename_arg = NULL;
        struct syscall *syscall;
        int key = 0;
 
@@ -206,8 +204,10 @@ processed 46 insns (limit 1000000) max_states_per_insn 0 total_states 12 peak_st
 
 #define __loop_iter(arg) \
        if (syscall->string_args_len[arg] != 0) { \
-               filename_len = syscall->string_args_len[arg]; \
-               filename_arg = (const void *)args->args[arg];
+               unsigned int filename_len = syscall->string_args_len[arg]; \
+               const void *filename_arg = (const void *)args->args[arg]; \
+               if (filename_len <= sizeof(augmented_args->filename.value)) \
+                       len += augmented_filename__read(&augmented_args->filename, filename_arg, filename_len);
 #define loop_iter_first() __loop_iter(0); }
 #define loop_iter(arg) else __loop_iter(arg); }
 #define loop_iter_last(arg) else __loop_iter(arg); __asm__ __volatile__("": : :"memory"); }
@@ -219,10 +219,6 @@ processed 46 insns (limit 1000000) max_states_per_insn 0 total_states 12 peak_st
        loop_iter(4)
        loop_iter_last(5)
 
-       if (filename_arg != NULL && filename_len <= sizeof(augmented_args->filename.value)) {
-               len += augmented_filename__read(&augmented_args->filename, filename_arg, filename_len);
-       }
-
        /* If perf_event_output fails, return non-zero so that it gets recorded unaugmented */
        return perf_event_output(args, &__augmented_syscalls__, BPF_F_CURRENT_CPU, augmented_args, len);
 }