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.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

15 files changed, 50 insertions, 46 deletions

diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h
index d62b56cf8c12..a30fad536f52 100644
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -1,8 +1,8 @@
 #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_ */
diff --git a/tools/lib/string.c b/tools/lib/string.c
index 8e678af1c6ee..bd239bc1d557 100644
--- a/tools/lib/string.c
+++ b/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;
-}
diff --git a/tools/lib/subcmd/help.c b/tools/lib/subcmd/help.c
index ba970a73d053..0310520f918e 100644
--- a/tools/lib/subcmd/help.c
+++ b/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);
diff --git a/tools/lib/subcmd/parse-options.c b/tools/lib/subcmd/parse-options.c
index 359bfa77f39c..2bd6fd0c1d40 100644
--- a/tools/lib/subcmd/parse-options.c
+++ b/tools/lib/subcmd/parse-options.c
@@ -368,7 +368,7 @@ retry:
                         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 @@ retry:
                                         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 @@ is_abbreviated:
                                 continue;
                         }
                         /* negated and abbreviated very much? */
-                        if (!prefixcmp("no-", arg)) {
+                        if (strstarts("no-", arg)) {
                                 flags |= OPT_UNSET;
                                 goto is_abbreviated;
                         }
@@ -416,7 +416,7 @@ is_abbreviated:
                         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 @@ opt:
                 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);
         }
 
diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
index ece45582a48d..3ddcc6e2abeb 100644
--- a/tools/perf/builtin-config.c
+++ b/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) {
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index dd26c62c9893..25a42acabee1 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/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"))
diff --git a/tools/perf/builtin-help.c b/tools/perf/builtin-help.c
index 530a7f2fa0f3..dbe4e4153bcf 100644
--- a/tools/perf/builtin-help.c
+++ b/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;
diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index 628a5e412cb1..e0279babe0c0 100644
--- a/tools/perf/perf.c
+++ b/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 */
diff --git a/tools/perf/ui/browser.c b/tools/perf/ui/browser.c
index f73f3f13e01d..d0c2007c307b 100644
--- a/tools/perf/ui/browser.c
+++ b/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) {
diff --git a/tools/perf/ui/browsers/annotate.c b/tools/perf/ui/browsers/annotate.c
index 8d3f6f53c122..6794a8bec404 100644
--- a/tools/perf/ui/browsers/annotate.c
+++ b/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;
diff --git a/tools/perf/ui/stdio/hist.c b/tools/perf/ui/stdio/hist.c
index 2df8eb1ed3c0..5c95b8301c67 100644
--- a/tools/perf/ui/stdio/hist.c
+++ b/tools/perf/ui/stdio/hist.c
@@ -1,4 +1,5 @@
 #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) {
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 4bd2d1d882af..4a1264c66101 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/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;
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 22d413ae6025..02130e2e72c7 100644
--- a/tools/perf/util/callchain.c
+++ b/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;
 
diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index 31a7dea248d0..bc75596f9e79 100644
--- a/tools/perf/util/config.c
+++ b/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. */
diff --git a/tools/perf/util/llvm-utils.c b/tools/perf/util/llvm-utils.c
index c6a15f204c03..209b0c82eff4 100644
--- a/tools/perf/util/llvm-utils.c
+++ b/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;