linux-kernel - [PATCH] perf script: Fix hex dump character output

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Date:   Wed, 12 Jan 2022 10:50:57 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] perf script: Fix hex dump character output

Using grep -C with perf script -D can give erroneous results as grep loses
lines due to non-printable characters, for example, below the 0020, 0060
and 0070 lines are missing:

 $ perf script -D | grep -C10 AUX | head
 .  0010:  08 00 00 00 00 00 00 00 1f 00 00 00 00 00 00 00  ................
 .  0030:  01 00 00 00 00 00 00 00 00 04 00 00 00 00 00 00  ................
 .  0040:  00 08 00 00 00 00 00 00 02 00 00 00 00 00 00 00  ................
 .  0050:  00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
 .  0080:  02 00 00 00 00 00 00 00 1b 00 00 00 00 00 00 00  ................
 .  0090:  00 00 00 00 00 00 00 00                          ........

 0 0 0x450 [0x98]: PERF_RECORD_AUXTRACE_INFO type: 1
   PMU Type            8
   Time Shift          31

perf's isprint() is a custom implementation from the kernel, but the
kernel's _ctype appears to include characters from Latin-1 Supplement which
is not compatible with, for example, UTF-8. Fix by checking also isascii().

After:

 $ tools/perf/perf script -D | grep -C10 AUX | head
 .  0010:  08 00 00 00 00 00 00 00 1f 00 00 00 00 00 00 00  ................
 .  0020:  03 84 32 2f 00 00 00 00 63 7c 4f d2 fa ff ff ff  ..2/....c|O.....
 .  0030:  01 00 00 00 00 00 00 00 00 04 00 00 00 00 00 00  ................
 .  0040:  00 08 00 00 00 00 00 00 02 00 00 00 00 00 00 00  ................
 .  0050:  00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
 .  0060:  00 02 00 00 00 00 00 00 00 c0 03 00 00 00 00 00  ................
 .  0070:  e2 00 00 00 00 00 00 00 02 00 00 00 00 00 00 00  ................
 .  0080:  02 00 00 00 00 00 00 00 1b 00 00 00 00 00 00 00  ................
 .  0090:  00 00 00 00 00 00 00 00                          ........

Fixes: 3052ba56bcb589 ("tools perf: Move from sane_ctype.h obtained from git to the Linux's original")
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 tools/perf/util/debug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
index c7a9fa0ffae9..7b5eec300d66 100644
--- a/tools/perf/util/debug.c
+++ b/tools/perf/util/debug.c
@@ -189,7 +189,7 @@ static int trace_event_printer(enum binary_printer_ops op,
 		break;
 	case BINARY_PRINT_CHAR_DATA:
 		printed += color_fprintf(fp, color, "%c",
-			      isprint(ch) ? ch : '.');
+			      isprint(ch) && isascii(ch) ? ch : '.');
 		break;
 	case BINARY_PRINT_CHAR_PAD:
 		printed += color_fprintf(fp, color, " ");
-- 
2.25.1