This commit adds a new concept 'function' to Kconfig. A function call
resembles a variable reference with arguments, and looks like this:
$(function arg1, arg2, arg3, ...)
(Actually, this syntax was inspired by Makefile.)
Real examples will look like this:
$(shell true)
$(cc-option -fstackprotector)
This commit adds the basic infrastructure to add, delete, evaluate
functions.
Also, add the first built-in function $(shell ...). This evaluates
to 'y' if the given command exits with 0, 'n' otherwise.
I am also planning to support user-defined functions (a.k.a 'macro')
for cases where hard-coding is not preferred.
If you want to try this feature, the hello-world code is someting below.
Example code:
config CC_IS_GCC
bool
default $(shell $CC --version | grep -q gcc)
config CC_IS_CLANG
bool
default $(shell $CC --version | grep -q clang)
config CC_HAS_OZ
bool
default $(shell $CC -Werror -Oz -c -x c /dev/null -o /dev/null)
Result:
$ make -s alldefconfig && tail -n 3 .config
CONFIG_CC_IS_GCC=y
# CONFIG_CC_IS_CLANG is not set
# CONFIG_CC_HAS_OZ is not set
$ make CC=clang -s alldefconfig && tail -n 3 .config
# CONFIG_CC_IS_GCC is not set
CONFIG_CC_IS_CLANG=y
CONFIG_CC_HAS_OZ=y
A function call can appear anywhere a symbol reference can appear.
So, the following code is possible.
Example code:
config CC_NAME
string
default "gcc" if $(shell $CC --version | grep -q gcc)
default "clang" if $(shell $CC --version | grep -q clang)
default "unknown compiler"
Result:
$ make -s alldefconfig && tail -n 1 .config
CONFIG_CC_NAME="gcc"
$ make CC=clang -s alldefconfig && tail -n 1 .config
CONFIG_CC_NAME="clang"
Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---
Reminder for myself:
Update Documentation/kbuild/kconfig-language.txt
scripts/kconfig/function.c | 149 ++++++++++++++++++++++++++++++++++++++++++++
scripts/kconfig/lkc_proto.h | 5 ++
scripts/kconfig/util.c | 46 +++++++++++---
scripts/kconfig/zconf.l | 38 ++++++++++-
scripts/kconfig/zconf.y | 9 +++
5 files changed, 238 insertions(+), 9 deletions(-)
create mode 100644 scripts/kconfig/function.c
diff --git a/scripts/kconfig/function.c b/scripts/kconfig/function.c
new file mode 100644
index 0000000..60e59be
--- /dev/null
+++ b/scripts/kconfig/function.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2018 Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "list.h"
+
+#define FUNCTION_MAX_ARGS 10
+
+static LIST_HEAD(function_list);
+
+struct function {
+ const char *name;
+ char *(*func)(int argc, char *argv[]);
+ struct list_head node;
+};
+
+static struct function *func_lookup(const char *name)
+{
+ struct function *f;
+
+ list_for_each_entry(f, &function_list, node) {
+ if (!strcmp(name, f->name))
+ return f;
+ }
+
+ return NULL;
+}
+
+static void func_add(const char *name, char *(*func)(int argc, char *argv[]))
+{
+ struct function *f;
+
+ f = func_lookup(name);
+ if (f) {
+ fprintf(stderr, "%s: function already exists. ignored.\n", name);
+ return;
+ }
+
+ f = xmalloc(sizeof(*f));
+ f->name = name;
+ f->func = func;
+
+ list_add_tail(&f->node, &function_list);
+}
+
+static void func_del(struct function *f)
+{
+ list_del(&f->node);
+ free(f);
+}
+
+static char *func_call(int argc, char *argv[])
+{
+ struct function *f;
+
+ f = func_lookup(argv[0]);
+ if (!f) {
+ fprintf(stderr, "%s: function not found\n", argv[0]);
+ return NULL;
+ }
+
+ return f->func(argc, argv);
+}
+
+static char *func_eval(const char *func)
+{
+ char *expanded, *saveptr, *str, *token, *res;
+ const char *delim;
+ int argc = 0;
+ char *argv[FUNCTION_MAX_ARGS];
+
+ expanded = expand_string_value(func);
+
+ str = expanded;
+ delim = " ";
+
+ while ((token = strtok_r(str, delim, &saveptr))) {
+ argv[argc++] = token;
+ str = NULL;
+ delim = ",";
+ }
+
+ res = func_call(argc, argv);
+
+ free(expanded);
+
+ return res ?: xstrdup("");
+}
+
+char *func_eval_n(const char *func, size_t n)
+{
+ char *tmp, *res;
+
+ tmp = xmalloc(n + 1);
+ memcpy(tmp, func, n);
+ *(tmp + n) = '\0';
+
+ res = func_eval(tmp);
+
+ free(tmp);
+
+ return res;
+}
+
+/* built-in functions */
+static char *do_shell(int argc, char *argv[])
+{
+ static const char *pre = "(";
+ static const char *post = ") >/dev/null 2>&1";
+ char *cmd;
+ int ret;
+
+ if (argc != 2)
+ return NULL;
+
+ /*
+ * Surround the command with ( ) in case it is piped commands.
+ * Also, redirect stdout and stderr to /dev/null.
+ */
+ cmd = xmalloc(strlen(pre) + strlen(argv[1]) + strlen(post) + 1);
+ strcpy(cmd, pre);
+ strcat(cmd, argv[1]);
+ strcat(cmd, post);
+
+ ret = system(cmd);
+
+ free(cmd);
+
+ return xstrdup(ret == 0 ? "y" : "n");
+}
+
+void func_init(void)
+{
+ /* register built-in functions */
+ func_add("shell", do_shell);
+}
+
+void func_exit(void)
+{
+ struct function *f, *tmp;
+
+ /* unregister all functions */
+ list_for_each_entry_safe(f, tmp, &function_list, node)
+ func_del(f);
+}
diff --git a/scripts/kconfig/lkc_proto.h b/scripts/kconfig/lkc_proto.h
index 9884adc..09a4f53 100644
--- a/scripts/kconfig/lkc_proto.h
+++ b/scripts/kconfig/lkc_proto.h
@@ -48,5 +48,10 @@ const char * sym_get_string_value(struct symbol *sym);
const char * prop_get_type_name(enum prop_type type);
+/* function.c */
+char *func_eval_n(const char *func, size_t n);
+void func_init(void);
+void func_exit(void);
+
/* expr.c */
void expr_print(struct expr *e, void (*fn)(void *, struct symbol *, const char *), void *data, int prevtoken);
diff --git a/scripts/kconfig/util.c b/scripts/kconfig/util.c
index dddf85b..ed89fb9 100644
--- a/scripts/kconfig/util.c
+++ b/scripts/kconfig/util.c
@@ -93,9 +93,10 @@ static char *env_expand_n(const char *name, size_t n)
}
/*
- * Expand environments embedded in the string given in argument. Environments
- * to be expanded shall be prefixed by a '$'. Unknown environment expands to
- * the empty string.
+ * Expand environments and functions embedded in the string given in argument.
+ * Environments to be expanded shall be prefixed by a '$'. Functions to be
+ * evaluated shall be surrounded by $(). Unknown environment/function expands
+ * to the empty string.
*/
char *expand_string_value(const char *in)
{
@@ -113,11 +114,40 @@ char *expand_string_value(const char *in)
while ((p = strchr(in, '$'))) {
char *new;
- q = p + 1;
- while (isalnum(*q) || *q == '_')
- q++;
-
- new = env_expand_n(p + 1, q - p - 1);
+ /*
+ * If the next character is '(', it is a function.
+ * Otherwise, environment.
+ */
+ if (*(p + 1) == '(') {
+ int nest = 0;
+
+ q = p + 2;
+ while (1) {
+ if (*q == '\0') {
+ fprintf(stderr,
+ "unterminated function: %s\n",
+ p);
+ new = xstrdup("");
+ break;
+ } else if (*q == '(') {
+ nest++;
+ } else if (*q == ')') {
+ if (nest-- == 0) {
+ new = func_eval_n(p + 2,
+ q - p - 2);
+ q++;
+ break;
+ }
+ }
+ q++;
+ }
+ } else {
+ q = p + 1;
+ while (isalnum(*q) || *q == '_')
+ q++;
+
+ new = env_expand_n(p + 1, q - p - 1);
+ }
reslen = strlen(res) + (p - in) + strlen(new) + 1;
res = xrealloc(res, reslen);
diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
index 0d89ea6..f433ab0 100644
--- a/scripts/kconfig/zconf.l
+++ b/scripts/kconfig/zconf.l
@@ -1,7 +1,7 @@
%option nostdinit noyywrap never-interactive full ecs
%option 8bit nodefault perf-report perf-report
%option noinput
-%x COMMAND HELP STRING PARAM
+%x COMMAND HELP STRING PARAM FUNCTION
%{
/*
* Copyright (C) 2002 Roman Zippel <zippel@xxxxxxxxxxxxxx>
@@ -25,6 +25,7 @@ static struct {
static char *text;
static int text_size, text_asize;
+static int function_nest;
struct buffer {
struct buffer *parent;
@@ -138,6 +139,12 @@ n [$A-Za-z0-9_-]
new_string();
BEGIN(STRING);
}
+ "$(" {
+ new_string();
+ append_string(yytext, yyleng);
+ function_nest = 0;
+ BEGIN(FUNCTION);
+ }
\n BEGIN(INITIAL); current_file->lineno++; return T_EOL;
({n}|[/.])+ {
const struct kconf_id *id = kconf_id_lookup(yytext, yyleng);
@@ -196,6 +203,35 @@ n [$A-Za-z0-9_-]
}
}
+<FUNCTION>{
+ [^()\n]* {
+ append_string(yytext, yyleng);
+ }
+ "(" {
+ append_string(yytext, yyleng);
+ function_nest++;
+ }
+ ")" {
+ append_string(yytext, yyleng);
+ if (function_nest-- == 0) {
+ BEGIN(PARAM);
+ yylval.string = text;
+ return T_WORD;
+ }
+ }
+ \n {
+ fprintf(stderr,
+ "%s:%d:warning: multi-line function not supported\n",
+ zconf_curname(), zconf_lineno());
+ current_file->lineno++;
+ BEGIN(INITIAL);
+ return T_EOL;
+ }
+ <<EOF>> {
+ BEGIN(INITIAL);
+ }
+}
+
<HELP>{
[ \t]+ {
ts = 0;
diff --git a/scripts/kconfig/zconf.y b/scripts/kconfig/zconf.y
index 784083d..d9977de 100644
--- a/scripts/kconfig/zconf.y
+++ b/scripts/kconfig/zconf.y
@@ -534,11 +534,19 @@ void conf_parse(const char *name)
zconf_initscan(name);
+ func_init();
_menu_init();
if (getenv("ZCONF_DEBUG"))
yydebug = 1;
yyparse();
+
+ /*
+ * Currently, functions are evaluated only when Kconfig files are
+ * parsed. We can free functions here.
+ */
+ func_exit();
+
if (yynerrs)
exit(1);
if (!modules_sym)
@@ -778,4 +786,5 @@ void zconfdump(FILE *out)
#include "confdata.c"
#include "expr.c"
#include "symbol.c"
+#include "function.c"
#include "menu.c"
--
2.7.4
--
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