[PATCH v12 1/4] perf check: introduce check subcommand

[Aditya Gupta <adityag@linux.ibm.com>]

Currently the presence of a feature is checked with a combination of
perf version --build-options and greps, such as:

    perf version --build-options | grep " on .* HAVE_FEATURE"

Instead of this, introduce a subcommand "perf check feature", with which
scripts can test for presence of a feature, such as:

    perf check feature HAVE_FEATURE

'perf check feature' command is expected to have exit status of 0 if
feature is built-in, and 1 if it's not built-in or if feature is not known.

Multiple features can also be passed as a comma-separated list, in which
case the exit status will be 1 only if all of the passed features are
built-in. For example, with below command, it will have exit status of 0
only if both libtraceevent and bpf are enabled, else 1 in all other cases

    perf check feature libtraceevent,bpf

The arguments are case-insensitive.
An array 'supported_features' has also been introduced that can be used by
other commands like 'perf version --build-options', so that new features
can be added in one place, with the array

Reviewed-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
---
 tools/perf/Build                        |   1 +
 tools/perf/Documentation/perf-check.txt |  79 +++++++++++
 tools/perf/builtin-check.c              | 178 ++++++++++++++++++++++++
 tools/perf/builtin.h                    |  17 +++
 tools/perf/perf.c                       |   1 +
 5 files changed, 276 insertions(+)
 create mode 100644 tools/perf/Documentation/perf-check.txt
 create mode 100644 tools/perf/builtin-check.c

diff --git a/tools/perf/Build b/tools/perf/Build
index 1d4957957d75..3e486f7df94b 100644
--- a/tools/perf/Build
+++ b/tools/perf/Build
@@ -1,5 +1,6 @@
 perf-bench-y += builtin-bench.o
 perf-y += builtin-annotate.o
+perf-y += builtin-check.o
 perf-y += builtin-config.o
 perf-y += builtin-diff.o
 perf-y += builtin-evlist.o
diff --git a/tools/perf/Documentation/perf-check.txt b/tools/perf/Documentation/perf-check.txt
new file mode 100644
index 000000000000..88cfd41a76cc
--- /dev/null
+++ b/tools/perf/Documentation/perf-check.txt
@@ -0,0 +1,79 @@
+perf-check(1)
+===============
+
+NAME
+----
+perf-check - check features in perf
+
+SYNOPSIS
+--------
+[verse]
+'perf check' [<options>]
+'perf check' {feature <feature_list>} [<options>]
+
+DESCRIPTION
+-----------
+With no options given, the 'perf check' just prints the perf version
+on the standard output.
+
+If the subcommand 'feature' is used, then status of feature is printed
+on the standard output (unless '-q' is also passed), ie. whether it is
+compiled-in/built-in or not.
+Also, 'perf check feature' returns with exit status 0 if the feature
+is built-in, otherwise returns with exit status 1.
+
+SUBCOMMANDS
+-----------
+
+feature::
+
+        Print whether feature(s) is compiled-in or not, and also returns with an
+        exit status of 0, if passed feature(s) are compiled-in, else 1.
+
+        It expects a feature list as an argument. There can be a single feature
+        name/macro, or multiple features can also be passed as a comma-separated
+        list, in which case the exit status will be 0 only if all of the passed
+        features are compiled-in.
+
+        The feature names/macros are case-insensitive.
+
+        Example Usage:
+                perf check feature libtraceevent
+                perf check feature HAVE_LIBTRACEEVENT
+                perf check feature libtraceevent,bpf
+
+        Supported feature names/macro:
+                aio                     /  HAVE_AIO_SUPPORT
+                bpf                     /  HAVE_LIBBPF_SUPPORT
+                bpf_skeletons           /  HAVE_BPF_SKEL
+                debuginfod              /  HAVE_DEBUGINFOD_SUPPORT
+                dwarf                   /  HAVE_DWARF_SUPPORT
+                dwarf_getlocations      /  HAVE_DWARF_GETLOCATIONS_SUPPORT
+                get_cpuid               /  HAVE_AUXTRACE_SUPPORT
+                numa_num_possible_cpus  /  HAVE_LIBNUMA_SUPPORT
+                libaudit                /  HAVE_LIBAUDIT_SUPPORT
+                libbfd                  /  HAVE_LIBBFD_SUPPORT
+                libelf                  /  HAVE_LIBELF_SUPPORT
+                libcrypto               /  HAVE_LIBCRYPTO_SUPPORT
+                libdw-dwarf-unwind      /  HAVE_DWARF_SUPPORT
+                libnuma                 /  HAVE_LIBNUMA_SUPPORT
+                libperl                 /  HAVE_LIBPERL_SUPPORT
+                libpfm4                 /  HAVE_LIBPFM
+                libpython               /  HAVE_LIBPYTHON_SUPPORT
+                libslang                /  HAVE_SLANG_SUPPORT
+                libtraceevent           /  HAVE_LIBTRACEEVENT
+                libunwind               /  HAVE_LIBUNWIND_SUPPORT
+                lzma                    /  HAVE_LZMA_SUPPORT
+                syscall_table           /  HAVE_SYSCALL_TABLE_SUPPORT
+                zlib                    /  HAVE_ZLIB_SUPPORT
+                zstd                    /  HAVE_ZSTD_SUPPORT
+
+OPTIONS
+-------
+-q::
+--quiet::
+        Do not print any messages or warnings
+
+        This can be used along with subcommands such as 'perf check feature'
+        to hide unnecessary output in test scripts, eg.
+        'perf check feature --quiet libtraceevent'
diff --git a/tools/perf/builtin-check.c b/tools/perf/builtin-check.c
new file mode 100644
index 000000000000..44ffde6f8dbe
--- /dev/null
+++ b/tools/perf/builtin-check.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "builtin.h"
+#include "color.h"
+#include "util/debug.h"
+#include "util/header.h"
+#include <tools/config.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <subcmd/parse-options.h>
+
+static const char * const check_subcommands[] = { "feature", NULL };
+static struct option check_options[] = {
+	OPT_BOOLEAN('q', "quiet", &quiet, "do not show any warnings or messages"),
+	OPT_END()
+};
+static struct option check_feature_options[] = { OPT_END() };
+
+static const char *check_usage[] = {
+	"perf check [<subcommand>] [<options>]",
+	NULL
+};
+static const char *check_feature_usage[] = {
+	"perf check feature <feature_list>",
+	NULL
+};
+
+struct feature_status supported_features[] = {
+	FEATURE_STATUS("aio", HAVE_AIO_SUPPORT),
+	FEATURE_STATUS("bpf", HAVE_LIBBPF_SUPPORT),
+	FEATURE_STATUS("bpf_skeletons", HAVE_BPF_SKEL),
+	FEATURE_STATUS("debuginfod", HAVE_DEBUGINFOD_SUPPORT),
+	FEATURE_STATUS("dwarf", HAVE_DWARF_SUPPORT),
+	FEATURE_STATUS("dwarf_getlocations", HAVE_DWARF_GETLOCATIONS_SUPPORT),
+	FEATURE_STATUS("dwarf-unwind-support", HAVE_DWARF_UNWIND_SUPPORT),
+	FEATURE_STATUS("get_cpuid", HAVE_AUXTRACE_SUPPORT),
+	FEATURE_STATUS("libaudit", HAVE_LIBAUDIT_SUPPORT),
+	FEATURE_STATUS("libbfd", HAVE_LIBBFD_SUPPORT),
+	FEATURE_STATUS("libcapstone", HAVE_LIBCAPSTONE_SUPPORT),
+	FEATURE_STATUS("libcrypto", HAVE_LIBCRYPTO_SUPPORT),
+	FEATURE_STATUS("libdw-dwarf-unwind", HAVE_DWARF_SUPPORT),
+	FEATURE_STATUS("libelf", HAVE_LIBELF_SUPPORT),
+	FEATURE_STATUS("libnuma", HAVE_LIBNUMA_SUPPORT),
+	FEATURE_STATUS("libopencsd", HAVE_CSTRACE_SUPPORT),
+	FEATURE_STATUS("libperl", HAVE_LIBPERL_SUPPORT),
+	FEATURE_STATUS("libpfm4", HAVE_LIBPFM),
+	FEATURE_STATUS("libpython", HAVE_LIBPYTHON_SUPPORT),
+	FEATURE_STATUS("libslang", HAVE_SLANG_SUPPORT),
+	FEATURE_STATUS("libtraceevent", HAVE_LIBTRACEEVENT),
+	FEATURE_STATUS("libunwind", HAVE_LIBUNWIND_SUPPORT),
+	FEATURE_STATUS("lzma", HAVE_LZMA_SUPPORT),
+	FEATURE_STATUS("numa_num_possible_cpus", HAVE_LIBNUMA_SUPPORT),
+	FEATURE_STATUS("syscall_table", HAVE_SYSCALL_TABLE_SUPPORT),
+	FEATURE_STATUS("zlib", HAVE_ZLIB_SUPPORT),
+	FEATURE_STATUS("zstd", HAVE_ZSTD_SUPPORT),
+
+	/* this should remain at end, to know the array end */
+	FEATURE_STATUS(NULL, _)
+};
+
+static void on_off_print(const char *status)
+{
+	printf("[ ");
+
+	if (!strcmp(status, "OFF"))
+		color_fprintf(stdout, PERF_COLOR_RED, "%-3s", status);
+	else
+		color_fprintf(stdout, PERF_COLOR_GREEN, "%-3s", status);
+
+	printf(" ]");
+}
+
+/* Helper function to print status of a feature along with name/macro */
+static void status_print(const char *name, const char *macro,
+			 const char *status)
+{
+	printf("%22s: ", name);
+	on_off_print(status);
+	printf("  # %s\n", macro);
+}
+
+#define STATUS(feature)                                           \
+do {                                                              \
+	if (feature.is_builtin)                                   \
+		status_print(feature.name, feature.macro, "on");  \
+	else                                                      \
+		status_print(feature.name, feature.macro, "OFF"); \
+} while (0)
+
+/**
+ * check whether "feature" is built-in with perf
+ *
+ * returns:
+ *    0: NOT built-in or Feature not known
+ *    1: Built-in
+ */
+static int has_support(const char *feature)
+{
+	for (int i = 0; supported_features[i].name; ++i) {
+		if ((strcasecmp(feature, supported_features[i].name) == 0) ||
+		    (strcasecmp(feature, supported_features[i].macro) == 0)) {
+			if (!quiet)
+				STATUS(supported_features[i]);
+			return supported_features[i].is_builtin;
+		}
+	}
+
+	if (!quiet)
+		pr_err("Feature not known: '%s'\n", feature);
+
+	return 0;
+}
+
+
+/**
+ * Usage: 'perf check feature <feature_list>'
+ *
+ * <feature_list> can be a single feature name/macro, or a comma-separated list
+ * of feature names/macros
+ * eg. argument can be "libtraceevent" or "libtraceevent,bpf" etc
+ *
+ * In case of a comma-separated list, feature_enabled will be 1, only if
+ * all features passed in the string are supported
+ *
+ * Note that argv will get modified
+ */
+static int subcommand_feature(int argc, const char **argv)
+{
+	char *feature_list;
+	char *feature_name;
+	int feature_enabled;
+
+	argc = parse_options(argc, argv, check_feature_options,
+			check_feature_usage, 0);
+
+	if (!argc)
+		usage_with_options(check_feature_usage, check_feature_options);
+
+	if (argc > 1) {
+		pr_err("Too many arguments passed to 'perf check feature'\n");
+		return -1;
+	}
+
+	feature_enabled = 1;
+	/* feature_list is a non-const copy of 'argv[0]' */
+	feature_list = strdup(argv[0]);
+	if (!feature_list) {
+		pr_err("ERROR: failed to allocate memory for feature list\n");
+		return -1;
+	}
+
+	feature_name = strtok(feature_list, ",");
+
+	while (feature_name) {
+		feature_enabled &= has_support(feature_name);
+		feature_name = strtok(NULL, ",");
+	}
+
+	free(feature_list);
+
+	return !feature_enabled;
+}
+
+int cmd_check(int argc, const char **argv)
+{
+	argc = parse_options_subcommand(argc, argv, check_options,
+			check_subcommands, check_usage, 0);
+
+	if (!argc)
+		usage_with_options(check_usage, check_options);
+
+	if (strcmp(argv[0], "feature") == 0)
+		return subcommand_feature(argc, argv);
+
+	/* If no subcommand matched above, print usage help */
+	usage_with_options(check_usage, check_options);
+	return 0;
+}
diff --git a/tools/perf/builtin.h b/tools/perf/builtin.h
index f4375deabfa3..94f4b3769bf7 100644
--- a/tools/perf/builtin.h
+++ b/tools/perf/builtin.h
@@ -2,6 +2,22 @@
 #ifndef BUILTIN_H
 #define BUILTIN_H
 
+#include <stddef.h>
+#include <linux/compiler.h>
+#include <tools/config.h>
+
+struct feature_status {
+	const char *name;
+	const char *macro;
+	int is_builtin;
+};
+
+#define FEATURE_STATUS(name_, macro_) {    \
+	.name = name_,                     \
+	.macro = #macro_,                  \
+	.is_builtin = IS_BUILTIN(macro_) }
+
+extern struct feature_status supported_features[];
 struct cmdnames;
 
 void list_common_cmds_help(void);
@@ -11,6 +27,7 @@ int cmd_annotate(int argc, const char **argv);
 int cmd_bench(int argc, const char **argv);
 int cmd_buildid_cache(int argc, const char **argv);
 int cmd_buildid_list(int argc, const char **argv);
+int cmd_check(int argc, const char **argv);
 int cmd_config(int argc, const char **argv);
 int cmd_c2c(int argc, const char **argv);
 int cmd_diff(int argc, const char **argv);
diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index bd3f80b5bb46..4def800f4089 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -52,6 +52,7 @@ static struct cmd_struct commands[] = {
 	{ "archive",	NULL,	0 },
 	{ "buildid-cache", cmd_buildid_cache, 0 },
 	{ "buildid-list", cmd_buildid_list, 0 },
+	{ "check",	cmd_check,	0 },
 	{ "config",	cmd_config,	0 },
 	{ "c2c",	cmd_c2c,	0 },
 	{ "diff",	cmd_diff,	0 },
-- 
2.45.2