1 files changed, 493 insertions, 0 deletions
diff --git a/tools/perf/builtin-help.c b/tools/perf/builtin-help.c
new file mode 100644
index 000000000..3d29d0524
--- /dev/null
+++ b/tools/perf/builtin-help.c
@@ -0,0 +1,493 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * builtin-help.c
+ *
+ * Builtin help command
+ */
+#include "perf.h"
+#include "util/config.h"
+#include "builtin.h"
+#include <subcmd/exec-cmd.h>
+#include "common-cmds.h"
+#include <subcmd/parse-options.h>
+#include <subcmd/run-command.h>
+#include <subcmd/help.h>
+#include "util/debug.h"
+#include <linux/kernel.h>
+#include <errno.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+static struct man_viewer_list {
+	struct man_viewer_list *next;
+	char name[0];
+} *man_viewer_list;
+
+static struct man_viewer_info_list {
+	struct man_viewer_info_list *next;
+	const char *info;
+	char name[0];
+} *man_viewer_info_list;
+
+enum help_format {
+	HELP_FORMAT_NONE,
+	HELP_FORMAT_MAN,
+	HELP_FORMAT_INFO,
+	HELP_FORMAT_WEB,
+};
+
+static enum help_format parse_help_format(const char *format)
+{
+	if (!strcmp(format, "man"))
+		return HELP_FORMAT_MAN;
+	if (!strcmp(format, "info"))
+		return HELP_FORMAT_INFO;
+	if (!strcmp(format, "web") || !strcmp(format, "html"))
+		return HELP_FORMAT_WEB;
+
+	pr_err("unrecognized help format '%s'", format);
+	return HELP_FORMAT_NONE;
+}
+
+static const char *get_man_viewer_info(const char *name)
+{
+	struct man_viewer_info_list *viewer;
+
+	for (viewer = man_viewer_info_list; viewer; viewer = viewer->next) {
+		if (!strcasecmp(name, viewer->name))
+			return viewer->info;
+	}
+	return NULL;
+}
+
+static int check_emacsclient_version(void)
+{
+	struct strbuf buffer = STRBUF_INIT;
+	struct child_process ec_process;
+	const char *argv_ec[] = { "emacsclient", "--version", NULL };
+	int version;
+	int ret = -1;
+
+	/* emacsclient prints its version number on stderr */
+	memset(&ec_process, 0, sizeof(ec_process));
+	ec_process.argv = argv_ec;
+	ec_process.err = -1;
+	ec_process.stdout_to_stderr = 1;
+	if (start_command(&ec_process)) {
+		fprintf(stderr, "Failed to start emacsclient.\n");
+		return -1;
+	}
+	if (strbuf_read(&buffer, ec_process.err, 20) < 0) {
+		fprintf(stderr, "Failed to read emacsclient version\n");
+		goto out;
+	}
+	close(ec_process.err);
+
+	/*
+	 * Don't bother checking return value, because "emacsclient --version"
+	 * seems to always exits with code 1.
+	 */
+	finish_command(&ec_process);
+
+	if (!strstarts(buffer.buf, "emacsclient")) {
+		fprintf(stderr, "Failed to parse emacsclient version.\n");
+		goto out;
+	}
+
+	version = atoi(buffer.buf + strlen("emacsclient"));
+
+	if (version < 22) {
+		fprintf(stderr,
+			"emacsclient version '%d' too old (< 22).\n",
+			version);
+	} else
+		ret = 0;
+out:
+	strbuf_release(&buffer);
+	return ret;
+}
+
+static void exec_failed(const char *cmd)
+{
+	char sbuf[STRERR_BUFSIZE];
+	pr_warning("failed to exec '%s': %s", cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
+}
+
+static void exec_woman_emacs(const char *path, const char *page)
+{
+	if (!check_emacsclient_version()) {
+		/* This works only with emacsclient version >= 22. */
+		char *man_page;
+
+		if (!path)
+			path = "emacsclient";
+		if (asprintf(&man_page, "(woman \"%s\")", page) > 0) {
+			execlp(path, "emacsclient", "-e", man_page, NULL);
+			free(man_page);
+		}
+		exec_failed(path);
+	}
+}
+
+static void exec_man_konqueror(const char *path, const char *page)
+{
+	const char *display = getenv("DISPLAY");
+
+	if (display && *display) {
+		char *man_page;
+		const char *filename = "kfmclient";
+
+		/* It's simpler to launch konqueror using kfmclient. */
+		if (path) {
+			const char *file = strrchr(path, '/');
+			if (file && !strcmp(file + 1, "konqueror")) {
+				char *new = strdup(path);
+				char *dest = strrchr(new, '/');
+
+				/* strlen("konqueror") == strlen("kfmclient") */
+				strcpy(dest + 1, "kfmclient");
+				path = new;
+			}
+			if (file)
+				filename = file;
+		} else
+			path = "kfmclient";
+		if (asprintf(&man_page, "man:%s(1)", page) > 0) {
+			execlp(path, filename, "newTab", man_page, NULL);
+			free(man_page);
+		}
+		exec_failed(path);
+	}
+}
+
+static void exec_man_man(const char *path, const char *page)
+{
+	if (!path)
+		path = "man";
+	execlp(path, "man", page, NULL);
+	exec_failed(path);
+}
+
+static void exec_man_cmd(const char *cmd, const char *page)
+{
+	char *shell_cmd;
+
+	if (asprintf(&shell_cmd, "%s %s", cmd, page) > 0) {
+		execl("/bin/sh", "sh", "-c", shell_cmd, NULL);
+		free(shell_cmd);
+	}
+	exec_failed(cmd);
+}
+
+static void add_man_viewer(const char *name)
+{
+	struct man_viewer_list **p = &man_viewer_list;
+	size_t len = strlen(name);
+
+	while (*p)
+		p = &((*p)->next);
+	*p = zalloc(sizeof(**p) + len + 1);
+	strcpy((*p)->name, name);
+}
+
+static int supported_man_viewer(const char *name, size_t len)
+{
+	return (!strncasecmp("man", name, len) ||
+		!strncasecmp("woman", name, len) ||
+		!strncasecmp("konqueror", name, len));
+}
+
+static void do_add_man_viewer_info(const char *name,
+				   size_t len,
+				   const char *value)
+{
+	struct man_viewer_info_list *new = zalloc(sizeof(*new) + len + 1);
+
+	strncpy(new->name, name, len);
+	new->info = strdup(value);
+	new->next = man_viewer_info_list;
+	man_viewer_info_list = new;
+}
+
+static void unsupported_man_viewer(const char *name, const char *var)
+{
+	pr_warning("'%s': path for unsupported man viewer.\n"
+		   "Please consider using 'man.<tool>.%s' instead.", name, var);
+}
+
+static int add_man_viewer_path(const char *name,
+			       size_t len,
+			       const char *value)
+{
+	if (supported_man_viewer(name, len))
+		do_add_man_viewer_info(name, len, value);
+	else
+		unsupported_man_viewer(name, "cmd");
+
+	return 0;
+}
+
+static int add_man_viewer_cmd(const char *name,
+			      size_t len,
+			      const char *value)
+{
+	if (supported_man_viewer(name, len))
+		unsupported_man_viewer(name, "path");
+	else
+		do_add_man_viewer_info(name, len, value);
+
+	return 0;
+}
+
+static int add_man_viewer_info(const char *var, const char *value)
+{
+	const char *name = var + 4;
+	const char *subkey = strrchr(name, '.');
+
+	if (!subkey) {
+		pr_err("Config with no key for man viewer: %s", name);
+		return -1;
+	}
+
+	if (!strcmp(subkey, ".path")) {
+		if (!value)
+			return config_error_nonbool(var);
+		return add_man_viewer_path(name, subkey - name, value);
+	}
+	if (!strcmp(subkey, ".cmd")) {
+		if (!value)
+			return config_error_nonbool(var);
+		return add_man_viewer_cmd(name, subkey - name, value);
+	}
+
+	pr_warning("'%s': unsupported man viewer sub key.", subkey);
+	return 0;
+}
+
+static int perf_help_config(const char *var, const char *value, void *cb)
+{
+	enum help_format *help_formatp = cb;
+
+	if (!strcmp(var, "help.format")) {
+		if (!value)
+			return config_error_nonbool(var);
+		*help_formatp = parse_help_format(value);
+		if (*help_formatp == HELP_FORMAT_NONE)
+			return -1;
+		return 0;
+	}
+	if (!strcmp(var, "man.viewer")) {
+		if (!value)
+			return config_error_nonbool(var);
+		add_man_viewer(value);
+		return 0;
+	}
+	if (strstarts(var, "man."))
+		return add_man_viewer_info(var, value);
+
+	return 0;
+}
+
+static struct cmdnames main_cmds, other_cmds;
+
+void list_common_cmds_help(void)
+{
+	unsigned int i, longest = 0;
+
+	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
+		if (longest < strlen(common_cmds[i].name))
+			longest = strlen(common_cmds[i].name);
+	}
+
+	puts(" The most commonly used perf commands are:");
+	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
+		printf("   %-*s   ", longest, common_cmds[i].name);
+		puts(common_cmds[i].help);
+	}
+}
+
+static const char *cmd_to_page(const char *perf_cmd)
+{
+	char *s;
+
+	if (!perf_cmd)
+		return "perf";
+	else if (strstarts(perf_cmd, "perf"))
+		return perf_cmd;
+
+	return asprintf(&s, "perf-%s", perf_cmd) < 0 ? NULL : s;
+}
+
+static void setup_man_path(void)
+{
+	char *new_path;
+	const char *old_path = getenv("MANPATH");
+
+	/* We should always put ':' after our path. If there is no
+	 * old_path, the ':' at the end will let 'man' to try
+	 * system-wide paths after ours to find the manual page. If
+	 * there is old_path, we need ':' as delimiter. */
+	if (asprintf(&new_path, "%s:%s", system_path(PERF_MAN_PATH), old_path ?: "") > 0) {
+		setenv("MANPATH", new_path, 1);
+		free(new_path);
+	} else {
+		pr_err("Unable to setup man path");
+	}
+}
+
+static void exec_viewer(const char *name, const char *page)
+{
+	const char *info = get_man_viewer_info(name);
+
+	if (!strcasecmp(name, "man"))
+		exec_man_man(info, page);
+	else if (!strcasecmp(name, "woman"))
+		exec_woman_emacs(info, page);
+	else if (!strcasecmp(name, "konqueror"))
+		exec_man_konqueror(info, page);
+	else if (info)
+		exec_man_cmd(info, page);
+	else
+		pr_warning("'%s': unknown man viewer.", name);
+}
+
+static int show_man_page(const char *perf_cmd)
+{
+	struct man_viewer_list *viewer;
+	const char *page = cmd_to_page(perf_cmd);
+	const char *fallback = getenv("PERF_MAN_VIEWER");
+
+	setup_man_path();
+	for (viewer = man_viewer_list; viewer; viewer = viewer->next)
+		exec_viewer(viewer->name, page); /* will return when unable */
+
+	if (fallback)
+		exec_viewer(fallback, page);
+	exec_viewer("man", page);
+
+	pr_err("no man viewer handled the request");
+	return -1;
+}
+
+static int show_info_page(const char *perf_cmd)
+{
+	const char *page = cmd_to_page(perf_cmd);
+	setenv("INFOPATH", system_path(PERF_INFO_PATH), 1);
+	execlp("info", "info", "perfman", page, NULL);
+	return -1;
+}
+
+static int get_html_page_path(char **page_path, const char *page)
+{
+	struct stat st;
+	const char *html_path = system_path(PERF_HTML_PATH);
+
+	/* Check that we have a perf documentation directory. */
+	if (stat(mkpath("%s/perf.html", html_path), &st)
+	    || !S_ISREG(st.st_mode)) {
+		pr_err("'%s': not a documentation directory.", html_path);
+		return -1;
+	}
+
+	return asprintf(page_path, "%s/%s.html", html_path, page);
+}
+
+/*
+ * If open_html is not defined in a platform-specific way (see for
+ * example compat/mingw.h), we use the script web--browse to display
+ * HTML.
+ */
+#ifndef open_html
+static void open_html(const char *path)
+{
+	execl_cmd("web--browse", "-c", "help.browser", path, NULL);
+}
+#endif
+
+static int show_html_page(const char *perf_cmd)
+{
+	const char *page = cmd_to_page(perf_cmd);
+	char *page_path; /* it leaks but we exec bellow */
+
+	if (get_html_page_path(&page_path, page) < 0)
+		return -1;
+
+	open_html(page_path);
+
+	return 0;
+}
+
+int cmd_help(int argc, const char **argv)
+{
+	bool show_all = false;
+	enum help_format help_format = HELP_FORMAT_MAN;
+	struct option builtin_help_options[] = {
+	OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
+	OPT_SET_UINT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
+	OPT_SET_UINT('w', "web", &help_format, "show manual in web browser",
+			HELP_FORMAT_WEB),
+	OPT_SET_UINT('i', "info", &help_format, "show info page",
+			HELP_FORMAT_INFO),
+	OPT_END(),
+	};
+	const char * const builtin_help_subcommands[] = {
+		"buildid-cache", "buildid-list", "diff", "evlist", "help", "list",
+		"record", "report", "bench", "stat", "timechart", "top", "annotate",
+		"script", "sched", "kallsyms", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
+#ifdef HAVE_LIBELF_SUPPORT
+		"probe",
+#endif
+#if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
+		"trace",
+#endif
+	NULL };
+	const char *builtin_help_usage[] = {
+		"perf help [--all] [--man|--web|--info] [command]",
+		NULL
+	};
+	int rc;
+
+	load_command_list("perf-", &main_cmds, &other_cmds);
+
+	rc = perf_config(perf_help_config, &help_format);
+	if (rc)
+		return rc;
+
+	argc = parse_options_subcommand(argc, argv, builtin_help_options,
+			builtin_help_subcommands, builtin_help_usage, 0);
+
+	if (show_all) {
+		printf("\n Usage: %s\n\n", perf_usage_string);
+		list_commands("perf commands", &main_cmds, &other_cmds);
+		printf(" %s\n\n", perf_more_info_string);
+		return 0;
+	}
+
+	if (!argv[0]) {
+		printf("\n usage: %s\n\n", perf_usage_string);
+		list_common_cmds_help();
+		printf("\n %s\n\n", perf_more_info_string);
+		return 0;
+	}
+
+	switch (help_format) {
+	case HELP_FORMAT_MAN:
+		rc = show_man_page(argv[0]);
+		break;
+	case HELP_FORMAT_INFO:
+		rc = show_info_page(argv[0]);
+		break;
+	case HELP_FORMAT_WEB:
+		rc = show_html_page(argv[0]);
+		break;
+	case HELP_FORMAT_NONE:
+		/* fall-through */
+	default:
+		rc = -1;
+		break;
+	}
+
+	return rc;
+}