[tip:perf/urgent] perf trace: Store the major number for a file when storing its pathname

[tip:perf/urgent] perf trace: Store the major number for a file when storing its pathname

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  4bcc4cff6a10e5287d4dd3e73b6b4689f9a0c570
Gitweb:     https://git.kernel.org/tip/4bcc4cff6a10e5287d4dd3e73b6b4689f9a0c570
Author:     Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Thu, 27 Dec 2018 13:32:59 -0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 28 Dec 2018 16:33:04 -0300

perf trace: Store the major number for a file when storing its pathname

We keep a table for the fds to map them back to pathnames when showing
'fd' based APIs such as write(), store as well the major number for the
device the path is in, to use in things like choosing the right ioctl
'cmd' beautifier.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-qjkds7bnk7v7fk2xhqsb0a4v@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-trace.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 41ab524e128b..4b03f66b1735 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -60,6 +60,7 @@
 #include <linux/stringify.h>
 #include <linux/time64.h>
 #include <fcntl.h>
+#include <sys/sysmacros.h>
 
 #include "sane_ctype.h"
 
@@ -959,6 +960,7 @@ static size_t fprintf_duration(unsigned long t, bool calculated, FILE *fp)
 
 struct file {
 	char *pathname;
+	int  dev_maj;
 };
 
 /**
@@ -1068,6 +1070,9 @@ static int trace__set_fd_pathname(struct thread *thread, int fd, const char *pat
 	struct file *file = thread_trace__files_entry(ttrace, fd);
 
 	if (file != NULL) {
+		struct stat st;
+		if (stat(pathname, &st) == 0)
+			file->dev_maj = major(st.st_rdev);
 		file->pathname = strdup(pathname);
 		if (file->pathname)
 			return 0;