tools include: Adopt strstarts() from the kernel

Replacing prefixcmp(), same purpose, inverted result, so standardize on
the kernel variant, to reduce silly differences among tools/ and the
kernel sources, making it easier for people to work in both codebases.

And then doing:

	if (strstarts(option, "no-"))

Looks clearer than doing:

	if (!prefixcmp(option, "no-"))

To figure out if option starts witn "no-".

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-kaei42gi7lpa8subwtv7eug8@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/include/linux/string.h

 #ifndef _TOOLS_LINUX_STRING_H_
 #define _TOOLS_LINUX_STRING_H_
 
-
 #include <linux/types.h>	/* for size_t */
+#include <string.h>
 
 void *memdup(const void *src, size_t len);
 
@@ -18,6 +18,14 @@ extern size_t strlcpy(char *dest, const char *src, size_t size);
 
 char *str_error_r(int errnum, char *buf, size_t buflen);
 
-int prefixcmp(const char *str, const char *prefix);
+/**
+ * strstarts - does @str start with @prefix?
+ * @str: string to examine
+ * @prefix: prefix to look for.
+ */
+static inline bool strstarts(const char *str, const char *prefix)
+{
+	return strncmp(str, prefix, strlen(prefix)) == 0;
+}
 
 #endif /* _LINUX_STRING_H_ */

tools/lib/string.c

@@ -87,12 +87,3 @@ size_t __weak strlcpy(char *dest, const char *src, size_t size)
 	}
 	return ret;
 }
-
-int prefixcmp(const char *str, const char *prefix)
-{
-	for (; ; str++, prefix++)
-		if (!*prefix)
-			return 0;
-		else if (*str != *prefix)
-			return (unsigned char)*prefix - (unsigned char)*str;
-}

tools/lib/subcmd/help.c

@@ -171,7 +171,7 @@ static void list_commands_in_dir(struct cmdnames *cmds,
 	while ((de = readdir(dir)) != NULL) {
 		int entlen;
 
-		if (prefixcmp(de->d_name, prefix))
+		if (!strstarts(de->d_name, prefix))
 			continue;
 
 		astrcat(&buf, de->d_name);

tools/lib/subcmd/parse-options.c

@@ -368,7 +368,7 @@ static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
 			return 0;
 		}
 		if (!rest) {
-			if (!prefixcmp(options->long_name, "no-")) {
+			if (strstarts(options->long_name, "no-")) {
 				/*
 				 * The long name itself starts with "no-", so
 				 * accept the option without "no-" so that users
@@ -381,7 +381,7 @@ static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
 					goto match;
 				}
 				/* Abbreviated case */
-				if (!prefixcmp(options->long_name + 3, arg)) {
+				if (strstarts(options->long_name + 3, arg)) {
 					flags |= OPT_UNSET;
 					goto is_abbreviated;
 				}
@@ -406,7 +406,7 @@ static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
 				continue;
 			}
 			/* negated and abbreviated very much? */
-			if (!prefixcmp("no-", arg)) {
+			if (strstarts("no-", arg)) {
 				flags |= OPT_UNSET;
 				goto is_abbreviated;
 			}
@@ -416,7 +416,7 @@ static int parse_long_opt(struct parse_opt_ctx_t *p, const char *arg,
 			flags |= OPT_UNSET;
 			rest = skip_prefix(arg + 3, options->long_name);
 			/* abbreviated and negated? */
-			if (!rest && !prefixcmp(options->long_name, arg + 3))
+			if (!rest && strstarts(options->long_name, arg + 3))
 				goto is_abbreviated;
 			if (!rest)
 				continue;
@@ -456,7 +456,7 @@ static void check_typos(const char *arg, const struct option *options)
 	if (strlen(arg) < 3)
 		return;
 
-	if (!prefixcmp(arg, "no-")) {
+	if (strstarts(arg, "no-")) {
 		fprintf(stderr, " Error: did you mean `--%s` (with two dashes ?)", arg);
 		exit(129);
 	}
@@ -464,7 +464,7 @@ static void check_typos(const char *arg, const struct option *options)
 	for (; options->type != OPTION_END; options++) {
 		if (!options->long_name)
 			continue;
-		if (!prefixcmp(options->long_name, arg)) {
+		if (strstarts(options->long_name, arg)) {
 			fprintf(stderr, " Error: did you mean `--%s` (with two dashes ?)", arg);
 			exit(129);
 		}
@@ -933,10 +933,10 @@ int parse_options_usage(const char * const *usagestr,
 		if (opts->long_name == NULL)
 			continue;
 
-		if (!prefixcmp(opts->long_name, optstr))
+		if (strstarts(opts->long_name, optstr))
 			print_option_help(opts, 0);
-		if (!prefixcmp("no-", optstr) &&
-		    !prefixcmp(opts->long_name, optstr + 3))
+		if (strstarts("no-", optstr) &&
+		    strstarts(opts->long_name, optstr + 3))
 			print_option_help(opts, 0);
 	}
 

tools/perf/builtin-config.c

@@ -13,6 +13,7 @@
 #include "util/util.h"
 #include "util/debug.h"
 #include "util/config.h"
+#include <linux/string.h>
 
 static bool use_system_config, use_user_config;
 
@@ -79,7 +80,7 @@ static int show_spec_config(struct perf_config_set *set, const char *var)
 		return -1;
 
 	perf_config_items__for_each_entry(&set->sections, section) {
-		if (prefixcmp(var, section->name) != 0)
+		if (!strstarts(var, section->name))
 			continue;
 
 		perf_config_items__for_each_entry(&section->items, item) {

tools/perf/builtin-ftrace.c

@@ -381,7 +381,7 @@ static int perf_ftrace_config(const char *var, const char *value, void *cb)
 {
 	struct perf_ftrace *ftrace = cb;
 
-	if (prefixcmp(var, "ftrace."))
+	if (!strstarts(var, "ftrace."))
 		return 0;
 
 	if (strcmp(var, "ftrace.tracer"))

tools/perf/builtin-help.c

@@ -90,7 +90,7 @@ static int check_emacsclient_version(void)
 	 */
 	finish_command(&ec_process);
 
-	if (prefixcmp(buffer.buf, "emacsclient")) {
+	if (!strstarts(buffer.buf, "emacsclient")) {
 		fprintf(stderr, "Failed to parse emacsclient version.\n");
 		goto out;
 	}
@@ -283,7 +283,7 @@ static int perf_help_config(const char *var, const char *value, void *cb)
 		add_man_viewer(value);
 		return 0;
 	}
-	if (!prefixcmp(var, "man."))
+	if (!strstarts(var, "man."))
 		return add_man_viewer_info(var, value);
 
 	return 0;
@@ -313,7 +313,7 @@ static const char *cmd_to_page(const char *perf_cmd)
 
 	if (!perf_cmd)
 		return "perf";
-	else if (!prefixcmp(perf_cmd, "perf"))
+	else if (!strstarts(perf_cmd, "perf"))
 		return perf_cmd;
 
 	return asprintf(&s, "perf-%s", perf_cmd) < 0 ? NULL : s;

tools/perf/perf.c

@@ -89,7 +89,7 @@ struct pager_config {
 static int pager_command_config(const char *var, const char *value, void *data)
 {
 	struct pager_config *c = data;
-	if (!prefixcmp(var, "pager.") && !strcmp(var + 6, c->cmd))
+	if (strstarts(var, "pager.") && !strcmp(var + 6, c->cmd))
 		c->val = perf_config_bool(var, value);
 	return 0;
 }
@@ -108,9 +108,9 @@ static int check_pager_config(const char *cmd)
 static int browser_command_config(const char *var, const char *value, void *data)
 {
 	struct pager_config *c = data;
-	if (!prefixcmp(var, "tui.") && !strcmp(var + 4, c->cmd))
+	if (strstarts(var, "tui.") && !strcmp(var + 4, c->cmd))
 		c->val = perf_config_bool(var, value);
-	if (!prefixcmp(var, "gtk.") && !strcmp(var + 4, c->cmd))
+	if (strstarts(var, "gtk.") && !strcmp(var + 4, c->cmd))
 		c->val = perf_config_bool(var, value) ? 2 : 0;
 	return 0;
 }
@@ -192,7 +192,7 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 		/*
 		 * Check remaining flags.
 		 */
-		if (!prefixcmp(cmd, CMD_EXEC_PATH)) {
+		if (strstarts(cmd, CMD_EXEC_PATH)) {
 			cmd += strlen(CMD_EXEC_PATH);
 			if (*cmd == '=')
 				set_argv_exec_path(cmd + 1);
@@ -229,7 +229,7 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 				*envchanged = 1;
 			(*argv)++;
 			(*argc)--;
-		} else if (!prefixcmp(cmd, CMD_DEBUGFS_DIR)) {
+		} else if (strstarts(cmd, CMD_DEBUGFS_DIR)) {
 			tracing_path_set(cmd + strlen(CMD_DEBUGFS_DIR));
 			fprintf(stderr, "dir: %s\n", tracing_path);
 			if (envchanged)
@@ -470,14 +470,14 @@ int main(int argc, const char **argv)
 	 * So we just directly call the internal command handler, and
 	 * die if that one cannot handle it.
 	 */
-	if (!prefixcmp(cmd, "perf-")) {
+	if (strstarts(cmd, "perf-")) {
 		cmd += 5;
 		argv[0] = cmd;
 		handle_internal_command(argc, argv);
 		fprintf(stderr, "cannot handle %s internally", cmd);
 		goto out;
 	}
-	if (!prefixcmp(cmd, "trace")) {
+	if (strstarts(cmd, "trace")) {
 #ifdef HAVE_LIBAUDIT_SUPPORT
 		setup_path();
 		argv[0] = "trace";
@@ -495,7 +495,7 @@ int main(int argc, const char **argv)
 	commit_pager_choice();
 
 	if (argc > 0) {
-		if (!prefixcmp(argv[0], "--"))
+		if (strstarts(argv[0], "--"))
 			argv[0] += 2;
 	} else {
 		/* The user didn't specify a command; give them help */

tools/perf/ui/browser.c

@@ -8,6 +8,7 @@
 #include <linux/compiler.h>
 #include <linux/list.h>
 #include <linux/rbtree.h>
+#include <linux/string.h>
 #include <stdlib.h>
 #include <sys/ttydefaults.h>
 #include "browser.h"
@@ -563,7 +564,7 @@ static int ui_browser__color_config(const char *var, const char *value,
 	int i;
 
 	/* same dir for all commands */
-	if (prefixcmp(var, "colors.") != 0)
+	if (!strstarts(var, "colors.") != 0)
 		return 0;
 
 	for (i = 0; ui_browser__colorsets[i].name != NULL; ++i) {

tools/perf/ui/browsers/annotate.c

@@ -13,6 +13,7 @@
 #include <inttypes.h>
 #include <pthread.h>
 #include <linux/kernel.h>
+#include <linux/string.h>
 #include <sys/ttydefaults.h>
 
 struct disasm_line_samples {
@@ -1198,7 +1199,7 @@ static int annotate__config(const char *var, const char *value,
 	struct annotate_config *cfg;
 	const char *name;
 
-	if (prefixcmp(var, "annotate.") != 0)
+	if (!strstarts(var, "annotate."))
 		return 0;
 
 	name = var + 9;

tools/perf/ui/stdio/hist.c

 #include <stdio.h>
+#include <linux/string.h>
 
 #include "../../util/util.h"
 #include "../../util/hist.h"
@@ -292,7 +293,7 @@ static size_t callchain__fprintf_graph(FILE *fp, struct rb_root *root,
 			 * displayed twice.
 			 */
 			if (!i++ && field_order == NULL &&
-			    sort_order && !prefixcmp(sort_order, "sym"))
+			    sort_order && strstarts(sort_order, "sym"))
 				continue;
 
 			if (!printed) {

tools/perf/util/bpf-loader.c

@@ -1246,7 +1246,7 @@ int bpf__config_obj(struct bpf_object *obj,
 	if (!obj || !term || !term->config)
 		return -EINVAL;
 
-	if (!prefixcmp(term->config, "map:")) {
+	if (strstarts(term->config, "map:")) {
 		key_scan_pos = sizeof("map:") - 1;
 		err = bpf__obj_config_map(obj, term, evlist, &key_scan_pos);
 		goto out;

tools/perf/util/callchain.c

@@ -304,7 +304,7 @@ int perf_callchain_config(const char *var, const char *value)
 {
 	char *endptr;
 
-	if (prefixcmp(var, "call-graph."))
+	if (!strstarts(var, "call-graph."))
 		return 0;
 	var += sizeof("call-graph.") - 1;
 

tools/perf/util/config.c

@@ -19,6 +19,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include <linux/string.h>
 
 #include "sane_ctype.h"
 
@@ -433,22 +434,22 @@ static int perf_ui_config(const char *var, const char *value)
 int perf_default_config(const char *var, const char *value,
 			void *dummy __maybe_unused)
 {
-	if (!prefixcmp(var, "core."))
+	if (strstarts(var, "core."))
 		return perf_default_core_config(var, value);
 
-	if (!prefixcmp(var, "hist."))
+	if (strstarts(var, "hist."))
 		return perf_hist_config(var, value);
 
-	if (!prefixcmp(var, "ui."))
+	if (strstarts(var, "ui."))
 		return perf_ui_config(var, value);
 
-	if (!prefixcmp(var, "call-graph."))
+	if (strstarts(var, "call-graph."))
 		return perf_callchain_config(var, value);
 
-	if (!prefixcmp(var, "llvm."))
+	if (strstarts(var, "llvm."))
 		return perf_llvm_config(var, value);
 
-	if (!prefixcmp(var, "buildid."))
+	if (strstarts(var, "buildid."))
 		return perf_buildid_config(var, value);
 
 	/* Add other config variables here. */

tools/perf/util/llvm-utils.c

@@ -33,7 +33,7 @@ struct llvm_param llvm_param = {
 
 int perf_llvm_config(const char *var, const char *value)
 {
-	if (prefixcmp(var, "llvm."))
+	if (!strstarts(var, "llvm."))
 		return 0;
 	var += sizeof("llvm.") - 1;