perf trace: Allow syscall_arg beautifiers to set a different return formatter

Things like fcntl will use this to set the right formatter based on its
'cmd' argument.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-4ea3wplb8b4j7aymj0d5uo0h@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 1f070bc..d48981c 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -908,6 +908,8 @@ static size_t fprintf_duration(unsigned long t, bool calculated, FILE *fp)
  * filename.ptr: The filename char pointer that will be vfs_getname'd
  * filename.entry_str_pos: Where to insert the string translated from
  *                         filename.ptr by the vfs_getname tracepoint/kprobe.
+ * ret_scnprintf: syscall args may set this to a different syscall return
+ *                formatter, for instance, fcntl may return fds, file flags, etc.
  */
 struct thread_trace {
        u64               entry_time;
@@ -916,6 +918,7 @@ struct thread_trace {
        unsigned long     pfmaj, pfmin;
        char              *entry_str;
        double            runtime_ms;
+       size_t            (*ret_scnprintf)(unsigned long value, char *bf, size_t size);
         struct {
                unsigned long ptr;
                short int     entry_str_pos;
@@ -966,6 +969,15 @@ fail:
        return NULL;
 }
 
+
+void syscall_arg__set_ret_scnprintf(struct syscall_arg *arg,
+                                   size_t (*ret_scnprintf)(unsigned long val, char *bf, size_t size))
+{
+       struct thread_trace *ttrace = thread__priv(arg->thread);
+
+       ttrace->ret_scnprintf = ret_scnprintf;
+}
+
 #define TRACE_PFMAJ            (1 << 0)
 #define TRACE_PFMIN            (1 << 1)
 
@@ -1390,6 +1402,14 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
 {
        size_t printed = 0;
        unsigned long val;
+       struct thread_trace *ttrace = thread__priv(thread);
+
+       /*
+        * Things like fcntl will set this in its 'cmd' formatter to pick the
+        * right formatter for the return value (an fd? file flags?), which is
+        * not needed for syscalls that always return a given type, say an fd.
+        */
+       ttrace->ret_scnprintf = NULL;
 
        if (sc->args != NULL) {
                struct format_field *field;
@@ -1704,7 +1724,12 @@ signed_print:
                fprintf(trace->output, ") = -1 %s %s", e, emsg);
        } else if (ret == 0 && sc->fmt->timeout)
                fprintf(trace->output, ") = 0 Timeout");
-       else if (sc->fmt->hexret)
+       else if (ttrace->ret_scnprintf) {
+               char bf[1024];
+               ttrace->ret_scnprintf(ret, bf, sizeof(bf));
+               ttrace->ret_scnprintf = NULL;
+               fprintf(trace->output, ") = %s", bf);
+       } else if (sc->fmt->hexret)
                fprintf(trace->output, ") = %#lx", ret);
        else if (sc->fmt->errpid) {
                struct thread *child = machine__find_thread(trace->host, ret, ret);

diff --git a/tools/perf/trace/beauty/beauty.h b/tools/perf/trace/beauty/beauty.h
index c05bb2e..a9613d2 100644 (file)
--- a/tools/perf/trace/beauty/beauty.h
+++ b/tools/perf/trace/beauty/beauty.h
@@ -54,4 +54,7 @@ size_t syscall_arg__scnprintf_statx_mask(char *bf, size_t size, struct syscall_a
 
 size_t open__scnprintf_flags(unsigned long flags, char *bf, size_t size);
 
+void syscall_arg__set_ret_scnprintf(struct syscall_arg *arg,
+                                   size_t (*ret_scnprintf)(unsigned long val, char *bf, size_t size));
+
 #endif /* _PERF_TRACE_BEAUTY_H */