perf trace: Beautify 'fsmount' arguments

Use existing beautifiers for the first arg, fd, assigned using the
heuristic that looks for syscall arg names and associates SCA_FD with
'fd' named argumes, and wire up the recently introduced fsmount
attr_flags table generator.

Now it should be possible to just use:

   perf trace -e fsmount

As root and see all fsmount syscalls with its args beautified.

  # cat sys_fsmount.c
  #define _GNU_SOURCE        /* See feature_test_macros(7) */
  #include <unistd.h>
  #include <sys/syscall.h>   /* For SYS_xxx definitions */

  #define __NR_fsmount 432

  #define MOUNT_ATTR_RDONLY	 0x00000001 /* Mount read-only */
  #define MOUNT_ATTR_NOSUID	 0x00000002 /* Ignore suid and sgid bits */
  #define MOUNT_ATTR_NODEV	 0x00000004 /* Disallow access to device special files */
  #define MOUNT_ATTR_NOEXEC	 0x00000008 /* Disallow program execution */
  #define MOUNT_ATTR__ATIME	 0x00000070 /* Setting on how atime should be updated */
  #define MOUNT_ATTR_RELATIME	 0x00000000 /* - Update atime relative to mtime/ctime. */
  #define MOUNT_ATTR_NOATIME	 0x00000010 /* - Do not update access times. */
  #define MOUNT_ATTR_STRICTATIME 0x00000020 /* - Always perform atime updates */
  #define MOUNT_ATTR_NODIRATIME	 0x00000080 /* Do not update directory access times */

  static inline int sys_fsmount(int fs_fd, int flags, int attr_flags)
  {
  	syscall(__NR_fsmount, fs_fd, flags, attr_flags);
  }

  int main(int argc, char *argv[])
  {
  	int attr_flags = 0, fs_fd = 0;

  	sys_fsmount(fs_fd++, 0, attr_flags);
  	attr_flags |= MOUNT_ATTR_RDONLY;
  	sys_fsmount(fs_fd++, 1, attr_flags);
  	attr_flags |= MOUNT_ATTR_NOSUID;
  	sys_fsmount(fs_fd++, 0, attr_flags);
  	attr_flags |= MOUNT_ATTR_NODEV;
  	sys_fsmount(fs_fd++, 1, attr_flags);
  	attr_flags |= MOUNT_ATTR_NOEXEC;
  	sys_fsmount(fs_fd++, 0, attr_flags);
  	attr_flags |= MOUNT_ATTR_NOATIME;
  	sys_fsmount(fs_fd++, 1, attr_flags);
  	attr_flags |= MOUNT_ATTR_STRICTATIME;
  	sys_fsmount(fs_fd++, 0, attr_flags);
  	attr_flags |= MOUNT_ATTR_NODIRATIME;
  	sys_fsmount(fs_fd++, 0, attr_flags);
  	return 0;
  }
  #
  # perf trace -e fsmount ./sys_fsmount
  fsmount(0, 0, MOUNT_ATTR_RELATIME)      = -1 EINVAL (Invalid argument)
  fsmount(1, FSMOUNT_CLOEXEC, MOUNT_ATTR_RDONLY|MOUNT_ATTR_RELATIME) = -1 EINVAL (Invalid argument)
  fsmount(2, 0, MOUNT_ATTR_RDONLY|MOUNT_ATTR_NOSUID|MOUNT_ATTR_RELATIME) = -1 EINVAL (Invalid argument)
  fsmount(3, FSMOUNT_CLOEXEC, MOUNT_ATTR_RDONLY|MOUNT_ATTR_NOSUID|MOUNT_ATTR_NODEV|MOUNT_ATTR_RELATIME) = -1 EBADF (Bad file descriptor)
  fsmount(4, 0, MOUNT_ATTR_RDONLY|MOUNT_ATTR_NOSUID|MOUNT_ATTR_NODEV|MOUNT_ATTR_NOEXEC|MOUNT_ATTR_RELATIME) = -1 EBADF (Bad file descriptor)
  fsmount(5, FSMOUNT_CLOEXEC, MOUNT_ATTR_RDONLY|MOUNT_ATTR_NOSUID|MOUNT_ATTR_NODEV|MOUNT_ATTR_NOEXEC|MOUNT_ATTR_NOATIME) = -1 EBADF (Bad file descriptor)
  fsmount(6, 0, MOUNT_ATTR_RDONLY|MOUNT_ATTR_NOSUID|MOUNT_ATTR_NODEV|MOUNT_ATTR_NOEXEC|MOUNT_ATTR_NOATIME|MOUNT_ATTR_STRICTATIME) = -1 EINVAL (Invalid argument)
  fsmount(7, 0, MOUNT_ATTR_RDONLY|MOUNT_ATTR_NOSUID|MOUNT_ATTR_NODEV|MOUNT_ATTR_NOEXEC|MOUNT_ATTR_NOATIME|MOUNT_ATTR_STRICTATIME|MOUNT_ATTR_NODIRATIME) = -1 EINVAL (Invalid argument)
  #

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
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-w71uge0sfo6ns9uclhwtthca@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Makefile.perf

@@ -419,6 +419,12 @@ fadvise_advice_tbl := $(srctree)/tools/perf/trace/beauty/fadvise.sh
 $(fadvise_advice_array): $(linux_uapi_dir)/in.h $(fadvise_advice_tbl)
 	$(Q)$(SHELL) '$(fadvise_advice_tbl)' $(linux_uapi_dir) > $@
 
+fsmount_arrays := $(beauty_outdir)/fsmount_arrays.c
+fsmount_tbls := $(srctree)/tools/perf/trace/beauty/fsmount.sh
+
+$(fsmount_arrays): $(linux_uapi_dir)/fs.h $(fsmount_tbls)
+	$(Q)$(SHELL) '$(fsmount_tbls)' $(linux_uapi_dir) > $@
+
 fspick_arrays := $(beauty_outdir)/fspick_arrays.c
 fspick_tbls := $(srctree)/tools/perf/trace/beauty/fspick.sh
 
@@ -647,6 +653,7 @@ build-dir   = $(if $(__build-dir),$(__build-dir),.)
 prepare: $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h archheaders $(drm_ioctl_array) \
 	$(fadvise_advice_array) \
 	$(fsconfig_arrays) \
+	$(fsmount_arrays) \
 	$(fspick_arrays) \
 	$(pkey_alloc_access_rights_array) \
 	$(sndrv_pcm_ioctl_array) \
@@ -944,6 +951,7 @@ clean:: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clea
 		$(OUTPUT)pmu-events/pmu-events.c \
 		$(OUTPUT)$(fadvise_advice_array) \
 		$(OUTPUT)$(fsconfig_arrays) \
+		$(OUTPUT)$(fsmount_arrays) \
 		$(OUTPUT)$(fspick_arrays) \
 		$(OUTPUT)$(madvise_behavior_array) \
 		$(OUTPUT)$(mmap_flags_array) \

tools/perf/builtin-trace.c

@@ -487,6 +487,11 @@ static const char *bpf_cmd[] = {
 };
 static DEFINE_STRARRAY(bpf_cmd, "BPF_");
 
+static const char *fsmount_flags[] = {
+	[1] = "CLOEXEC",
+};
+static DEFINE_STRARRAY(fsmount_flags, "FSMOUNT_");
+
 #include "trace/beauty/generated/fsconfig_arrays.c"
 
 static DEFINE_STRARRAY(fsconfig_cmds, "FSCONFIG_");
@@ -651,6 +656,10 @@ static size_t syscall_arg__scnprintf_getrandom_flags(char *bf, size_t size,
 	  { .scnprintf	= SCA_STRARRAY, \
 	    .parm	= &strarray__##array, }
 
+#define STRARRAY_FLAGS(name, array) \
+	  { .scnprintf	= SCA_STRARRAY_FLAGS, \
+	    .parm	= &strarray__##array, }
+
 #include "trace/beauty/arch_errno_names.c"
 #include "trace/beauty/eventfd.c"
 #include "trace/beauty/futex_op.c"
@@ -724,6 +733,9 @@ static struct syscall_fmt {
 	  .arg = { [1] = { .scnprintf = SCA_FLOCK, /* cmd */ }, }, },
 	{ .name     = "fsconfig",
 	  .arg = { [1] = STRARRAY(cmd, fsconfig_cmds), }, },
+	{ .name     = "fsmount",
+	  .arg = { [1] = STRARRAY_FLAGS(flags, fsmount_flags),
+		   [2] = { .scnprintf = SCA_FSMOUNT_ATTR_FLAGS, /* attr_flags */ }, }, },
 	{ .name     = "fspick",
 	  .arg = { [0] = { .scnprintf = SCA_FDAT,	  /* dfd */ },
 		   [1] = { .scnprintf = SCA_FILENAME,	  /* path */ },

tools/perf/trace/beauty/Build

@@ -1,6 +1,7 @@
 perf-y += clone.o
 perf-y += fcntl.o
 perf-y += flock.o
+perf-y += fsmount.o
 perf-y += fspick.o
 ifeq ($(SRCARCH),$(filter $(SRCARCH),x86))
 perf-y += ioctl.o

tools/perf/trace/beauty/beauty.h

@@ -144,6 +144,9 @@ size_t syscall_arg__scnprintf_fcntl_arg(char *bf, size_t size, struct syscall_ar
 size_t syscall_arg__scnprintf_flock(char *bf, size_t size, struct syscall_arg *arg);
 #define SCA_FLOCK syscall_arg__scnprintf_flock
 
+size_t syscall_arg__scnprintf_fsmount_attr_flags(char *bf, size_t size, struct syscall_arg *arg);
+#define SCA_FSMOUNT_ATTR_FLAGS syscall_arg__scnprintf_fsmount_attr_flags
+
 size_t syscall_arg__scnprintf_fspick_flags(char *bf, size_t size, struct syscall_arg *arg);
 #define SCA_FSPICK_FLAGS syscall_arg__scnprintf_fspick_flags
 

tools/perf/trace/beauty/fsmount.c

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * trace/beauty/fsmount.c
+ *
+ *  Copyright (C) 2019, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
+ */
+
+#include "trace/beauty/beauty.h"
+#include <linux/log2.h>
+#include <uapi/linux/mount.h>
+
+static size_t fsmount__scnprintf_attr_flags(unsigned long flags, char *bf, size_t size, bool show_prefix)
+{
+#include "trace/beauty/generated/fsmount_arrays.c"
+       static DEFINE_STRARRAY(fsmount_attr_flags, "MOUNT_ATTR_");
+       size_t printed = 0;
+
+       if ((flags & ~MOUNT_ATTR__ATIME) != 0)
+	       printed += strarray__scnprintf_flags(&strarray__fsmount_attr_flags, bf, size, show_prefix, flags);
+
+       if ((flags & MOUNT_ATTR__ATIME) == MOUNT_ATTR_RELATIME) {
+	       printed += scnprintf(bf + printed, size - printed, "%s%s%s",
+			            printed ? "|" : "", show_prefix ? "MOUNT_ATTR_" : "", "RELATIME");
+       }
+
+       return printed;
+}
+
+size_t syscall_arg__scnprintf_fsmount_attr_flags(char *bf, size_t size, struct syscall_arg *arg)
+{
+	unsigned long flags = arg->val;
+
+	return fsmount__scnprintf_attr_flags(flags, bf, size, arg->show_string_prefix);
+}