perf trace: Beautify statx syscall 'flag' and 'mask' arguments

To test it, build samples/statx/test_statx, which I did as:

$ make headers_install
$ cc -I ~/git/linux/usr/include samples/statx/test-statx.c -o /tmp/statx

And then use perf trace on it:

# perf trace -e statx /tmp/statx /etc/passwd
statx(/etc/passwd) = 0
results=7ff
Size: 3496 Blocks: 8 IO Block: 4096 regular file
Device: fd:00 Inode: 280156 Links: 1
Access: (0644/-rw-r--r--) Uid: 0 Gid: 0
Access: 2017-03-29 16:01:01.650073438-0300
Modify: 2017-03-10 16:25:14.156479354-0300
Change: 2017-03-10 16:25:14.171479328-0300
0.000 ( 0.007 ms): statx/30648 statx(dfd: CWD, filename: 0x7ef503f4, flags: SYMLINK_NOFOLLOW, mask: TYPE|MODE|NLINK|UID|GID|ATIME|MTIME|CTIME|INO|SIZE|BLOCKS|BTIME, buffer: 0x7fff7ef4eb10) = 0
#

Using the test-stat.c options to change the mask:

# perf trace -e statx /tmp/statx -O /etc/passwd > /dev/null
0.000 ( 0.008 ms): statx/30745 statx(dfd: CWD, filename: 0x3a0753f4, flags: SYMLINK_NOFOLLOW, mask: BTIME, buffer: 0x7ffd3a0735c0) = 0
#
# perf trace -e statx /tmp/statx -A /etc/passwd > /dev/null
0.000 ( 0.010 ms): statx/30757 statx(dfd: CWD, filename: 0xa94e63f4, flags: SYMLINK_NOFOLLOW|NO_AUTOMOUNT, mask: TYPE|MODE|NLINK|UID|GID|ATIME|MTIME|CTIME|INO|SIZE|BLOCKS|BTIME, buffer: 0x7ffea94e49d0) = 0
#
# trace --no-inherit -e statx /tmp/statx -F /etc/passwd > /dev/null
0.000 ( 0.011 ms): statx(dfd: CWD, filename: 0x3b02d3f3, flags: SYMLINK_NOFOLLOW|STATX_FORCE_SYNC, mask: TYPE|MODE|NLINK|UID|GID|ATIME|MTIME|CTIME|INO|SIZE|BLOCKS|BTIME, buffer: 0x7ffd3b02c850) = 0
#
# trace --no-inherit -e statx /tmp/statx -F -L /etc/passwd > /dev/null
0.000 ( 0.008 ms): statx(dfd: CWD, filename: 0x15cff3f3, flags: STATX_FORCE_SYNC, mask: TYPE|MODE|NLINK|UID|GID|ATIME|MTIME|CTIME|INO|SIZE|BLOCKS|BTIME, buffer: 0x7fff15cfdda0) = 0
#
# trace --no-inherit -e statx /tmp/statx -D -O /etc/passwd > /dev/null
0.000 ( 0.009 ms): statx(dfd: CWD, filename: 0xfa37f3f3, flags: SYMLINK_NOFOLLOW|STATX_DONT_SYNC, mask: BTIME, buffer: 0x7ffffa37da20) = 0
#

Adding a probe to get the filename collected as well:

# perf probe 'vfs_getname=getname_flags:72 pathname=result->name:string'
Added new event:
probe:vfs_getname (on getname_flags:72 with pathname=result->name:string)

You can now use it in all perf tools, such as:

perf record -e probe:vfs_getname -aR sleep 1

# trace --no-inherit -e statx /tmp/statx -D -O /etc/passwd > /dev/null
0.169 ( 0.007 ms): statx(dfd: CWD, filename: /etc/passwd, flags: SYMLINK_NOFOLLOW|STATX_DONT_SYNC, mask: BTIME, buffer: 0x7ffda9bf50f0) = 0
#

Same technique could be used to collect and beautify the result put in
the 'buffer' argument.

Finally do a system wide 'perf trace' session looking for any use of statx,
then run the test proggie with various flags:

# trace -e statx
16612.967 ( 0.028 ms): statx/4562 statx(dfd: CWD, filename: /tmp/statx, flags: SYMLINK_NOFOLLOW, mask: TYPE|MODE|NLINK|UID|GID|ATIME|MTIME|CTIME|INO|SIZE|BLOCKS|BTIME, buffer: 0x7ffef195d660) = 0
33064.447 ( 0.011 ms): statx/4569 statx(dfd: CWD, filename: /tmp/statx, flags: SYMLINK_NOFOLLOW|STATX_FORCE_SYNC, mask: TYPE|MODE|NLINK|UID|GID|ATIME|MTIME|CTIME|INO|SIZE|BLOCKS|BTIME, buffer: 0x7ffc5484c790) = 0
36050.891 ( 0.023 ms): statx/4576 statx(dfd: CWD, filename: /tmp/statx, flags: SYMLINK_NOFOLLOW, mask: BTIME, buffer: 0x7ffeb18b66e0) = 0
38039.889 ( 0.023 ms): statx/4584 statx(dfd: CWD, filename: /tmp/statx, flags: SYMLINK_NOFOLLOW, mask: TYPE|MODE|NLINK|UID|GID|ATIME|MTIME|CTIME|INO|SIZE|BLOCKS|BTIME, buffer: 0x7fff1db0ea90) = 0
^C#

This one also starts moving the beautifiers from files directly included
in builtin-trace.c to separate objects + a beauty.h header with
prototypes, so that we can add test cases in tools/perf/tests/ to fire
syscalls with various arguments and then get them intercepted as
syscalls:sys_enter_foo or raw_syscalls:sys_enter + sys_exit to then
format and check that the formatted output is the one we expect.

Cc: Adrian Hunter <[e-mail]>
Cc: Al Viro <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: David Howells <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/Build

···
 libperf-y += arch/
 libperf-y += ui/
 libperf-y += scripts/
+libperf-y += trace/beauty/
 
 gtk-y += ui/gtk/

tools/perf/arch/x86/entry/syscalls/syscall_64.tbl

···
 329	common	pkey_mprotect		sys_pkey_mprotect
 330	common	pkey_alloc		sys_pkey_alloc
 331	common	pkey_free		sys_pkey_free
+332	common	statx			sys_statx
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact

tools/perf/builtin-trace.c

···
 #include "util/intlist.h"
 #include "util/thread_map.h"
 #include "util/stat.h"
+#include "trace/beauty/beauty.h"
 #include "trace-event.h"
 #include "util/parse-events.h"
 #include "util/bpf-loader.h"
···
 #define perf_evsel__sc_tp_ptr(evsel, name, sample) \
 	({ struct syscall_tp *fields = evsel->priv; \
 	   fields->name.pointer(&fields->name, sample); })
-
-struct syscall_arg {
-	unsigned long val;
-	struct thread *thread;
-	struct trace  *trace;
-	void	      *parm;
-	u8	      idx;
-	u8	      mask;
-};
 
 struct strarray {
 	int	    offset;
···
 	  .arg_parm	 = { [0] = &strarray__socket_families, /* family */ }, },
 	{ .name	    = "stat",	    .errmsg = true, .alias = "newstat", },
 	{ .name	    = "statfs",	    .errmsg = true, },
+	{ .name	    = "statx",	    .errmsg = true,
+	  .arg_scnprintf = { [0] = SCA_FDAT, /* flags */
+			     [2] = SCA_STATX_FLAGS, /* flags */
+			     [3] = SCA_STATX_MASK, /* mask */ }, },
 	{ .name	    = "swapoff",    .errmsg = true,
 	  .arg_scnprintf = { [0] = SCA_FILENAME, /* specialfile */ }, },
 	{ .name	    = "swapon",	    .errmsg = true,

tools/perf/trace/beauty/Build

···
+libperf-y += statx.o

tools/perf/trace/beauty/beauty.h

···
+#ifndef _PERF_TRACE_BEAUTY_H
+#define _PERF_TRACE_BEAUTY_H
+
+#include <linux/types.h>
+
+struct trace;
+struct thread;
+
+struct syscall_arg {
+	unsigned long val;
+	struct thread *thread;
+	struct trace  *trace;
+	void	      *parm;
+	u8	      idx;
+	u8	      mask;
+};
+
+size_t syscall_arg__scnprintf_statx_flags(char *bf, size_t size, struct syscall_arg *arg);
+#define SCA_STATX_FLAGS syscall_arg__scnprintf_statx_flags
+
+size_t syscall_arg__scnprintf_statx_mask(char *bf, size_t size, struct syscall_arg *arg);
+#define SCA_STATX_MASK syscall_arg__scnprintf_statx_mask
+
+#endif /* _PERF_TRACE_BEAUTY_H */

tools/perf/trace/beauty/statx.c

···
+/*
+ * trace/beauty/statx.c
+ *
+ *  Copyright (C) 2017, Red Hat Inc, Arnaldo Carvalho de Melo <[e-mail]>
+ *
+ * Released under the GPL v2. (and only v2, not any later version)
+ */
+
+#include "trace/beauty/beauty.h"
+#include <linux/kernel.h>
+#include <sys/types.h>
+#include <uapi/linux/fcntl.h>
+#include <uapi/linux/stat.h>
+
+size_t syscall_arg__scnprintf_statx_flags(char *bf, size_t size, struct syscall_arg *arg)
+{
+	int printed = 0, flags = arg->val;
+
+	if (flags == 0)
+		return scnprintf(bf, size, "SYNC_AS_STAT");
+#define	P_FLAG(n) \
+	if (flags & AT_##n) { \
+		printed += scnprintf(bf + printed, size - printed, "%s%s", printed ? "|" : "", #n); \
+		flags &= ~AT_##n; \
+	}
+
+	P_FLAG(SYMLINK_NOFOLLOW);
+	P_FLAG(REMOVEDIR);
+	P_FLAG(SYMLINK_FOLLOW);
+	P_FLAG(NO_AUTOMOUNT);
+	P_FLAG(EMPTY_PATH);
+	P_FLAG(STATX_FORCE_SYNC);
+	P_FLAG(STATX_DONT_SYNC);
+
+#undef P_FLAG
+
+	if (flags)
+		printed += scnprintf(bf + printed, size - printed, "%s%#x", printed ? "|" : "", flags);
+
+	return printed;
+}
+
+size_t syscall_arg__scnprintf_statx_mask(char *bf, size_t size, struct syscall_arg *arg)
+{
+	int printed = 0, flags = arg->val;
+
+#define	P_FLAG(n) \
+	if (flags & STATX_##n) { \
+		printed += scnprintf(bf + printed, size - printed, "%s%s", printed ? "|" : "", #n); \
+		flags &= ~STATX_##n; \
+	}
+
+	P_FLAG(TYPE);
+	P_FLAG(MODE);
+	P_FLAG(NLINK);
+	P_FLAG(UID);
+	P_FLAG(GID);
+	P_FLAG(ATIME);
+	P_FLAG(MTIME);
+	P_FLAG(CTIME);
+	P_FLAG(INO);
+	P_FLAG(SIZE);
+	P_FLAG(BLOCKS);
+	P_FLAG(BTIME);
+
+#undef P_FLAG
+
+	if (flags)
+		printed += scnprintf(bf + printed, size - printed, "%s%#x", printed ? "|" : "", flags);
+
+	return printed;
+}