Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 995 insertions, 0 deletions

diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
new file mode 100644
index 000000000..7988149dc
--- /dev/null
+++ b/tools/perf/util/config.c
@@ -0,0 +1,995 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * config.c
+ *
+ * Helper functions for parsing config items.
+ * Originally copied from GIT source.
+ *
+ * Copyright (C) Linus Torvalds, 2005
+ * Copyright (C) Johannes Schindelin, 2005
+ *
+ */
+#include <errno.h>
+#include <sys/param.h>
+#include "cache.h"
+#include "callchain.h"
+#include "header.h"
+#include <subcmd/exec-cmd.h>
+#include "util/event.h"  /* proc_map_timeout */
+#include "util/hist.h"  /* perf_hist_config */
+#include "util/stat.h"  /* perf_stat__set_big_num */
+#include "util/evsel.h"  /* evsel__hw_names, evsel__use_bpf_counters */
+#include "srcline.h"
+#include "build-id.h"
+#include "debug.h"
+#include "config.h"
+#include "unwind.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <linux/string.h>
+#include <linux/zalloc.h>
+#include <linux/ctype.h>
+
+#define MAXNAME (256)
+
+#define DEBUG_CACHE_DIR ".debug"
+
+#define METRIC_ONLY_LEN 20
+
+static struct stats walltime_nsecs_stats;
+
+struct perf_stat_config stat_config = {
+	.aggr_mode		= AGGR_GLOBAL,
+	.aggr_level		= MAX_CACHE_LVL + 1,
+	.scale			= true,
+	.unit_width		= 4, /* strlen("unit") */
+	.run_count		= 1,
+	.metric_only_len	= METRIC_ONLY_LEN,
+	.walltime_nsecs_stats	= &walltime_nsecs_stats,
+	.big_num		= true,
+	.ctl_fd			= -1,
+	.ctl_fd_ack		= -1,
+	.iostat_run		= false,
+};
+
+char buildid_dir[MAXPATHLEN]; /* root dir for buildid, binary cache */
+
+static FILE *config_file;
+static const char *config_file_name;
+static int config_linenr;
+static int config_file_eof;
+static struct perf_config_set *config_set;
+
+const char *config_exclusive_filename;
+
+static int get_next_char(void)
+{
+	int c;
+	FILE *f;
+
+	c = '\n';
+	if ((f = config_file) != NULL) {
+		c = fgetc(f);
+		if (c == '\r') {
+			/* DOS like systems */
+			c = fgetc(f);
+			if (c != '\n') {
+				ungetc(c, f);
+				c = '\r';
+			}
+		}
+		if (c == '\n')
+			config_linenr++;
+		if (c == EOF) {
+			config_file_eof = 1;
+			c = '\n';
+		}
+	}
+	return c;
+}
+
+static char *parse_value(void)
+{
+	static char value[1024];
+	int quote = 0, comment = 0, space = 0;
+	size_t len = 0;
+
+	for (;;) {
+		int c = get_next_char();
+
+		if (len >= sizeof(value) - 1)
+			return NULL;
+		if (c == '\n') {
+			if (quote)
+				return NULL;
+			value[len] = 0;
+			return value;
+		}
+		if (comment)
+			continue;
+		if (isspace(c) && !quote) {
+			space = 1;
+			continue;
+		}
+		if (!quote) {
+			if (c == ';' || c == '#') {
+				comment = 1;
+				continue;
+			}
+		}
+		if (space) {
+			if (len)
+				value[len++] = ' ';
+			space = 0;
+		}
+		if (c == '\\') {
+			c = get_next_char();
+			switch (c) {
+			case '\n':
+				continue;
+			case 't':
+				c = '\t';
+				break;
+			case 'b':
+				c = '\b';
+				break;
+			case 'n':
+				c = '\n';
+				break;
+			/* Some characters escape as themselves */
+			case '\\': case '"':
+				break;
+			/* Reject unknown escape sequences */
+			default:
+				return NULL;
+			}
+			value[len++] = c;
+			continue;
+		}
+		if (c == '"') {
+			quote = 1-quote;
+			continue;
+		}
+		value[len++] = c;
+	}
+}
+
+static inline int iskeychar(int c)
+{
+	return isalnum(c) || c == '-' || c == '_';
+}
+
+static int get_value(config_fn_t fn, void *data, char *name, unsigned int len)
+{
+	int c;
+	char *value;
+
+	/* Get the full name */
+	for (;;) {
+		c = get_next_char();
+		if (config_file_eof)
+			break;
+		if (!iskeychar(c))
+			break;
+		name[len++] = c;
+		if (len >= MAXNAME)
+			return -1;
+	}
+	name[len] = 0;
+	while (c == ' ' || c == '\t')
+		c = get_next_char();
+
+	value = NULL;
+	if (c != '\n') {
+		if (c != '=')
+			return -1;
+		value = parse_value();
+		if (!value)
+			return -1;
+	}
+	return fn(name, value, data);
+}
+
+static int get_extended_base_var(char *name, int baselen, int c)
+{
+	do {
+		if (c == '\n')
+			return -1;
+		c = get_next_char();
+	} while (isspace(c));
+
+	/* We require the format to be '[base "extension"]' */
+	if (c != '"')
+		return -1;
+	name[baselen++] = '.';
+
+	for (;;) {
+		int ch = get_next_char();
+
+		if (ch == '\n')
+			return -1;
+		if (ch == '"')
+			break;
+		if (ch == '\\') {
+			ch = get_next_char();
+			if (ch == '\n')
+				return -1;
+		}
+		name[baselen++] = ch;
+		if (baselen > MAXNAME / 2)
+			return -1;
+	}
+
+	/* Final ']' */
+	if (get_next_char() != ']')
+		return -1;
+	return baselen;
+}
+
+static int get_base_var(char *name)
+{
+	int baselen = 0;
+
+	for (;;) {
+		int c = get_next_char();
+		if (config_file_eof)
+			return -1;
+		if (c == ']')
+			return baselen;
+		if (isspace(c))
+			return get_extended_base_var(name, baselen, c);
+		if (!iskeychar(c) && c != '.')
+			return -1;
+		if (baselen > MAXNAME / 2)
+			return -1;
+		name[baselen++] = tolower(c);
+	}
+}
+
+static int perf_parse_file(config_fn_t fn, void *data)
+{
+	int comment = 0;
+	int baselen = 0;
+	static char var[MAXNAME];
+
+	/* U+FEFF Byte Order Mark in UTF8 */
+	static const unsigned char *utf8_bom = (unsigned char *) "\xef\xbb\xbf";
+	const unsigned char *bomptr = utf8_bom;
+
+	for (;;) {
+		int line, c = get_next_char();
+
+		if (bomptr && *bomptr) {
+			/* We are at the file beginning; skip UTF8-encoded BOM
+			 * if present. Sane editors won't put this in on their
+			 * own, but e.g. Windows Notepad will do it happily. */
+			if ((unsigned char) c == *bomptr) {
+				bomptr++;
+				continue;
+			} else {
+				/* Do not tolerate partial BOM. */
+				if (bomptr != utf8_bom)
+					break;
+				/* No BOM at file beginning. Cool. */
+				bomptr = NULL;
+			}
+		}
+		if (c == '\n') {
+			if (config_file_eof)
+				return 0;
+			comment = 0;
+			continue;
+		}
+		if (comment || isspace(c))
+			continue;
+		if (c == '#' || c == ';') {
+			comment = 1;
+			continue;
+		}
+		if (c == '[') {
+			baselen = get_base_var(var);
+			if (baselen <= 0)
+				break;
+			var[baselen++] = '.';
+			var[baselen] = 0;
+			continue;
+		}
+		if (!isalpha(c))
+			break;
+		var[baselen] = tolower(c);
+
+		/*
+		 * The get_value function might or might not reach the '\n',
+		 * so saving the current line number for error reporting.
+		 */
+		line = config_linenr;
+		if (get_value(fn, data, var, baselen+1) < 0) {
+			config_linenr = line;
+			break;
+		}
+	}
+	pr_err("bad config file line %d in %s\n", config_linenr, config_file_name);
+	return -1;
+}
+
+static int parse_unit_factor(const char *end, unsigned long *val)
+{
+	if (!*end)
+		return 1;
+	else if (!strcasecmp(end, "k")) {
+		*val *= 1024;
+		return 1;
+	}
+	else if (!strcasecmp(end, "m")) {
+		*val *= 1024 * 1024;
+		return 1;
+	}
+	else if (!strcasecmp(end, "g")) {
+		*val *= 1024 * 1024 * 1024;
+		return 1;
+	}
+	return 0;
+}
+
+static int perf_parse_llong(const char *value, long long *ret)
+{
+	if (value && *value) {
+		char *end;
+		long long val = strtoll(value, &end, 0);
+		unsigned long factor = 1;
+
+		if (!parse_unit_factor(end, &factor))
+			return 0;
+		*ret = val * factor;
+		return 1;
+	}
+	return 0;
+}
+
+static int perf_parse_long(const char *value, long *ret)
+{
+	if (value && *value) {
+		char *end;
+		long val = strtol(value, &end, 0);
+		unsigned long factor = 1;
+		if (!parse_unit_factor(end, &factor))
+			return 0;
+		*ret = val * factor;
+		return 1;
+	}
+	return 0;
+}
+
+static void bad_config(const char *name)
+{
+	if (config_file_name)
+		pr_warning("bad config value for '%s' in %s, ignoring...\n", name, config_file_name);
+	else
+		pr_warning("bad config value for '%s', ignoring...\n", name);
+}
+
+int perf_config_u64(u64 *dest, const char *name, const char *value)
+{
+	long long ret = 0;
+
+	if (!perf_parse_llong(value, &ret)) {
+		bad_config(name);
+		return -1;
+	}
+
+	*dest = ret;
+	return 0;
+}
+
+int perf_config_int(int *dest, const char *name, const char *value)
+{
+	long ret = 0;
+	if (!perf_parse_long(value, &ret)) {
+		bad_config(name);
+		return -1;
+	}
+	*dest = ret;
+	return 0;
+}
+
+int perf_config_u8(u8 *dest, const char *name, const char *value)
+{
+	long ret = 0;
+
+	if (!perf_parse_long(value, &ret)) {
+		bad_config(name);
+		return -1;
+	}
+	*dest = ret;
+	return 0;
+}
+
+static int perf_config_bool_or_int(const char *name, const char *value, int *is_bool)
+{
+	int ret;
+
+	*is_bool = 1;
+	if (!value)
+		return 1;
+	if (!*value)
+		return 0;
+	if (!strcasecmp(value, "true") || !strcasecmp(value, "yes") || !strcasecmp(value, "on"))
+		return 1;
+	if (!strcasecmp(value, "false") || !strcasecmp(value, "no") || !strcasecmp(value, "off"))
+		return 0;
+	*is_bool = 0;
+	return perf_config_int(&ret, name, value) < 0 ? -1 : ret;
+}
+
+int perf_config_bool(const char *name, const char *value)
+{
+	int discard;
+	return !!perf_config_bool_or_int(name, value, &discard);
+}
+
+static const char *perf_config_dirname(const char *name, const char *value)
+{
+	if (!name)
+		return NULL;
+	return value;
+}
+
+static int perf_buildid_config(const char *var, const char *value)
+{
+	/* same dir for all commands */
+	if (!strcmp(var, "buildid.dir")) {
+		const char *dir = perf_config_dirname(var, value);
+
+		if (!dir) {
+			pr_err("Invalid buildid directory!\n");
+			return -1;
+		}
+		strncpy(buildid_dir, dir, MAXPATHLEN-1);
+		buildid_dir[MAXPATHLEN-1] = '\0';
+	}
+
+	return 0;
+}
+
+static int perf_default_core_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "core.proc-map-timeout"))
+		proc_map_timeout = strtoul(value, NULL, 10);
+
+	if (!strcmp(var, "core.addr2line-timeout"))
+		symbol_conf.addr2line_timeout_ms = strtoul(value, NULL, 10);
+
+	if (!strcmp(var, "core.addr2line-disable-warn"))
+		symbol_conf.addr2line_disable_warn = perf_config_bool(var, value);
+
+	/* Add other config variables here. */
+	return 0;
+}
+
+static int perf_ui_config(const char *var, const char *value)
+{
+	/* Add other config variables here. */
+	if (!strcmp(var, "ui.show-headers"))
+		symbol_conf.show_hist_headers = perf_config_bool(var, value);
+
+	return 0;
+}
+
+void perf_stat__set_big_num(int set)
+{
+	stat_config.big_num = (set != 0);
+}
+
+static void perf_stat__set_no_csv_summary(int set)
+{
+	stat_config.no_csv_summary = (set != 0);
+}
+
+static int perf_stat_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "stat.big-num"))
+		perf_stat__set_big_num(perf_config_bool(var, value));
+
+	if (!strcmp(var, "stat.no-csv-summary"))
+		perf_stat__set_no_csv_summary(perf_config_bool(var, value));
+
+	if (!strcmp(var, "stat.bpf-counter-events"))
+		evsel__bpf_counter_events = strdup(value);
+
+	/* Add other config variables here. */
+	return 0;
+}
+
+int perf_default_config(const char *var, const char *value,
+			void *dummy __maybe_unused)
+{
+	if (strstarts(var, "core."))
+		return perf_default_core_config(var, value);
+
+	if (strstarts(var, "hist."))
+		return perf_hist_config(var, value);
+
+	if (strstarts(var, "ui."))
+		return perf_ui_config(var, value);
+
+	if (strstarts(var, "call-graph."))
+		return perf_callchain_config(var, value);
+
+	if (strstarts(var, "buildid."))
+		return perf_buildid_config(var, value);
+
+	if (strstarts(var, "stat."))
+		return perf_stat_config(var, value);
+
+	if (strstarts(var, "addr2line."))
+		return addr2line_configure(var, value, dummy);
+
+	if (strstarts(var, "unwind."))
+		return unwind__configure(var, value, dummy);
+
+	/* Add other config variables here. */
+	return 0;
+}
+
+static int perf_config_from_file(config_fn_t fn, const char *filename, void *data)
+{
+	int ret;
+	FILE *f = fopen(filename, "r");
+
+	ret = -1;
+	if (f) {
+		config_file = f;
+		config_file_name = filename;
+		config_linenr = 1;
+		config_file_eof = 0;
+		ret = perf_parse_file(fn, data);
+		fclose(f);
+		config_file_name = NULL;
+	}
+	return ret;
+}
+
+const char *perf_etc_perfconfig(void)
+{
+	static const char *system_wide;
+	if (!system_wide)
+		system_wide = system_path(ETC_PERFCONFIG);
+	return system_wide;
+}
+
+static int perf_env_bool(const char *k, int def)
+{
+	const char *v = getenv(k);
+	return v ? perf_config_bool(k, v) : def;
+}
+
+int perf_config_system(void)
+{
+	return !perf_env_bool("PERF_CONFIG_NOSYSTEM", 0);
+}
+
+int perf_config_global(void)
+{
+	return !perf_env_bool("PERF_CONFIG_NOGLOBAL", 0);
+}
+
+static char *home_perfconfig(void)
+{
+	const char *home = NULL;
+	char *config;
+	struct stat st;
+	char path[PATH_MAX];
+
+	home = getenv("HOME");
+
+	/*
+	 * Skip reading user config if:
+	 *   - there is no place to read it from (HOME)
+	 *   - we are asked not to (PERF_CONFIG_NOGLOBAL=1)
+	 */
+	if (!home || !*home || !perf_config_global())
+		return NULL;
+
+	config = strdup(mkpath(path, sizeof(path), "%s/.perfconfig", home));
+	if (config == NULL) {
+		pr_warning("Not enough memory to process %s/.perfconfig, ignoring it.\n", home);
+		return NULL;
+	}
+
+	if (stat(config, &st) < 0)
+		goto out_free;
+
+	if (st.st_uid && (st.st_uid != geteuid())) {
+		pr_warning("File %s not owned by current user or root, ignoring it.\n", config);
+		goto out_free;
+	}
+
+	if (st.st_size)
+		return config;
+
+out_free:
+	free(config);
+	return NULL;
+}
+
+const char *perf_home_perfconfig(void)
+{
+	static const char *config;
+	static bool failed;
+
+	if (failed || config)
+		return config;
+
+	config = home_perfconfig();
+	if (!config)
+		failed = true;
+
+	return config;
+}
+
+static struct perf_config_section *find_section(struct list_head *sections,
+						const char *section_name)
+{
+	struct perf_config_section *section;
+
+	list_for_each_entry(section, sections, node)
+		if (!strcmp(section->name, section_name))
+			return section;
+
+	return NULL;
+}
+
+static struct perf_config_item *find_config_item(const char *name,
+						 struct perf_config_section *section)
+{
+	struct perf_config_item *item;
+
+	list_for_each_entry(item, &section->items, node)
+		if (!strcmp(item->name, name))
+			return item;
+
+	return NULL;
+}
+
+static struct perf_config_section *add_section(struct list_head *sections,
+					       const char *section_name)
+{
+	struct perf_config_section *section = zalloc(sizeof(*section));
+
+	if (!section)
+		return NULL;
+
+	INIT_LIST_HEAD(&section->items);
+	section->name = strdup(section_name);
+	if (!section->name) {
+		pr_debug("%s: strdup failed\n", __func__);
+		free(section);
+		return NULL;
+	}
+
+	list_add_tail(&section->node, sections);
+	return section;
+}
+
+static struct perf_config_item *add_config_item(struct perf_config_section *section,
+						const char *name)
+{
+	struct perf_config_item *item = zalloc(sizeof(*item));
+
+	if (!item)
+		return NULL;
+
+	item->name = strdup(name);
+	if (!item->name) {
+		pr_debug("%s: strdup failed\n", __func__);
+		free(item);
+		return NULL;
+	}
+
+	list_add_tail(&item->node, &section->items);
+	return item;
+}
+
+static int set_value(struct perf_config_item *item, const char *value)
+{
+	char *val = strdup(value);
+
+	if (!val)
+		return -1;
+
+	zfree(&item->value);
+	item->value = val;
+	return 0;
+}
+
+static int collect_config(const char *var, const char *value,
+			  void *perf_config_set)
+{
+	int ret = -1;
+	char *ptr, *key;
+	char *section_name, *name;
+	struct perf_config_section *section = NULL;
+	struct perf_config_item *item = NULL;
+	struct perf_config_set *set = perf_config_set;
+	struct list_head *sections;
+
+	if (set == NULL)
+		return -1;
+
+	sections = &set->sections;
+	key = ptr = strdup(var);
+	if (!key) {
+		pr_debug("%s: strdup failed\n", __func__);
+		return -1;
+	}
+
+	section_name = strsep(&ptr, ".");
+	name = ptr;
+	if (name == NULL || value == NULL)
+		goto out_free;
+
+	section = find_section(sections, section_name);
+	if (!section) {
+		section = add_section(sections, section_name);
+		if (!section)
+			goto out_free;
+	}
+
+	item = find_config_item(name, section);
+	if (!item) {
+		item = add_config_item(section, name);
+		if (!item)
+			goto out_free;
+	}
+
+	/* perf_config_set can contain both user and system config items.
+	 * So we should know where each value is from.
+	 * The classification would be needed when a particular config file
+	 * is overwritten by setting feature i.e. set_config().
+	 */
+	if (strcmp(config_file_name, perf_etc_perfconfig()) == 0) {
+		section->from_system_config = true;
+		item->from_system_config = true;
+	} else {
+		section->from_system_config = false;
+		item->from_system_config = false;
+	}
+
+	ret = set_value(item, value);
+
+out_free:
+	free(key);
+	return ret;
+}
+
+int perf_config_set__collect(struct perf_config_set *set, const char *file_name,
+			     const char *var, const char *value)
+{
+	config_file_name = file_name;
+	return collect_config(var, value, set);
+}
+
+static int perf_config_set__init(struct perf_config_set *set)
+{
+	int ret = -1;
+
+	/* Setting $PERF_CONFIG makes perf read _only_ the given config file. */
+	if (config_exclusive_filename)
+		return perf_config_from_file(collect_config, config_exclusive_filename, set);
+	if (perf_config_system() && !access(perf_etc_perfconfig(), R_OK)) {
+		if (perf_config_from_file(collect_config, perf_etc_perfconfig(), set) < 0)
+			goto out;
+	}
+	if (perf_config_global() && perf_home_perfconfig()) {
+		if (perf_config_from_file(collect_config, perf_home_perfconfig(), set) < 0)
+			goto out;
+	}
+
+out:
+	return ret;
+}
+
+struct perf_config_set *perf_config_set__new(void)
+{
+	struct perf_config_set *set = zalloc(sizeof(*set));
+
+	if (set) {
+		INIT_LIST_HEAD(&set->sections);
+		perf_config_set__init(set);
+	}
+
+	return set;
+}
+
+struct perf_config_set *perf_config_set__load_file(const char *file)
+{
+	struct perf_config_set *set = zalloc(sizeof(*set));
+
+	if (set) {
+		INIT_LIST_HEAD(&set->sections);
+		perf_config_from_file(collect_config, file, set);
+	}
+
+	return set;
+}
+
+static int perf_config__init(void)
+{
+	if (config_set == NULL)
+		config_set = perf_config_set__new();
+
+	return config_set == NULL;
+}
+
+int perf_config_set(struct perf_config_set *set,
+		    config_fn_t fn, void *data)
+{
+	int ret = 0;
+	char key[BUFSIZ];
+	struct perf_config_section *section;
+	struct perf_config_item *item;
+
+	perf_config_set__for_each_entry(set, section, item) {
+		char *value = item->value;
+
+		if (value) {
+			scnprintf(key, sizeof(key), "%s.%s",
+				  section->name, item->name);
+			ret = fn(key, value, data);
+			if (ret < 0) {
+				pr_err("Error in the given config file: wrong config key-value pair %s=%s\n",
+				       key, value);
+				/*
+				 * Can't be just a 'break', as perf_config_set__for_each_entry()
+				 * expands to two nested for() loops.
+				 */
+				goto out;
+			}
+		}
+	}
+out:
+	return ret;
+}
+
+int perf_config(config_fn_t fn, void *data)
+{
+	if (config_set == NULL && perf_config__init())
+		return -1;
+
+	return perf_config_set(config_set, fn, data);
+}
+
+void perf_config__exit(void)
+{
+	perf_config_set__delete(config_set);
+	config_set = NULL;
+}
+
+static void perf_config_item__delete(struct perf_config_item *item)
+{
+	zfree(&item->name);
+	zfree(&item->value);
+	free(item);
+}
+
+static void perf_config_section__purge(struct perf_config_section *section)
+{
+	struct perf_config_item *item, *tmp;
+
+	list_for_each_entry_safe(item, tmp, &section->items, node) {
+		list_del_init(&item->node);
+		perf_config_item__delete(item);
+	}
+}
+
+static void perf_config_section__delete(struct perf_config_section *section)
+{
+	perf_config_section__purge(section);
+	zfree(&section->name);
+	free(section);
+}
+
+static void perf_config_set__purge(struct perf_config_set *set)
+{
+	struct perf_config_section *section, *tmp;
+
+	list_for_each_entry_safe(section, tmp, &set->sections, node) {
+		list_del_init(&section->node);
+		perf_config_section__delete(section);
+	}
+}
+
+void perf_config_set__delete(struct perf_config_set *set)
+{
+	if (set == NULL)
+		return;
+
+	perf_config_set__purge(set);
+	free(set);
+}
+
+/*
+ * Call this to report error for your variable that should not
+ * get a boolean value (i.e. "[my] var" means "true").
+ */
+int config_error_nonbool(const char *var)
+{
+	pr_err("Missing value for '%s'", var);
+	return -1;
+}
+
+void set_buildid_dir(const char *dir)
+{
+	if (dir)
+		scnprintf(buildid_dir, MAXPATHLEN, "%s", dir);
+
+	/* default to $HOME/.debug */
+	if (buildid_dir[0] == '\0') {
+		char *home = getenv("HOME");
+
+		if (home) {
+			snprintf(buildid_dir, MAXPATHLEN, "%s/%s",
+				 home, DEBUG_CACHE_DIR);
+		} else {
+			strncpy(buildid_dir, DEBUG_CACHE_DIR, MAXPATHLEN-1);
+		}
+		buildid_dir[MAXPATHLEN-1] = '\0';
+	}
+	/* for communicating with external commands */
+	setenv("PERF_BUILDID_DIR", buildid_dir, 1);
+}
+
+struct perf_config_scan_data {
+	const char *name;
+	const char *fmt;
+	const char *value;
+	va_list args;
+	int ret;
+};
+
+static int perf_config_scan_cb(const char *var, const char *value, void *data)
+{
+	struct perf_config_scan_data *d = data;
+
+	if (!strcmp(var, d->name))
+		d->ret = vsscanf(value, d->fmt, d->args);
+
+	return 0;
+}
+
+int perf_config_scan(const char *name, const char *fmt, ...)
+{
+	struct perf_config_scan_data d = {
+		.name = name,
+		.fmt = fmt,
+	};
+
+	va_start(d.args, fmt);
+	perf_config(perf_config_scan_cb, &d);
+	va_end(d.args);
+
+	return d.ret;
+}
+
+static int perf_config_get_cb(const char *var, const char *value, void *data)
+{
+	struct perf_config_scan_data *d = data;
+
+	if (!strcmp(var, d->name))
+		d->value = value;
+
+	return 0;
+}
+
+const char *perf_config_get(const char *name)
+{
+	struct perf_config_scan_data d = {
+		.name = name,
+		.value = NULL,
+	};
+
+	perf_config(perf_config_get_cb, &d);
+	return d.value;
+}