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Message-ID: <CAFkk2KTOyQtPuEvh3aWGKFcy2QU8rz_yH_C5vmep078JEqe3Zg@mail.gmail.com> Date: Sun, 1 Apr 2018 08:49:51 +0200 From: Ulf Magnusson <ulfalizer@...il.com> To: Masahiro Yamada <yamada.masahiro@...ionext.com> Cc: Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>, Sam Ravnborg <sam@...nborg.org>, Linus Torvalds <torvalds@...ux-foundation.org>, Arnd Bergmann <arnd@...db.de>, Kees Cook <keescook@...omium.org>, Thomas Gleixner <tglx@...utronix.de>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Randy Dunlap <rdunlap@...radead.org>, "Luis R . Rodriguez" <mcgrof@...nel.org>, Nicolas Pitre <nico@...aro.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: Re: [PATCH v2 09/21] kconfig: add 'macro' keyword to support user-defined function On Sun, Apr 1, 2018 at 8:05 AM, Ulf Magnusson <ulfalizer@...il.com> wrote: > On Tue, Mar 27, 2018 at 7:29 AM, Masahiro Yamada > <yamada.masahiro@...ionext.com> wrote: >> Now, we got a basic ability to test compiler capability in Kconfig. >> >> config CC_HAS_STACKPROTECTOR >> def_bool $(shell (($CC -Werror -fstack-protector -c -x c /dev/null -o /dev/null) && echo y) || echo n) >> >> This works, but it is ugly to repeat this long boilerplate. >> >> We want to describe like this: >> >> config CC_HAS_STACKPROTECTOR >> bool >> default $(cc-option -fstack-protector) >> >> It is straight-forward to add a new function, but I do not like to >> hard-code specialized functions like this. Hence, here is another >> feature to add functions from Kconfig files. >> >> A user-defined function is defined with a special keyword 'macro'. >> It can be referenced in the same way as built-in functions. This >> feature was also inspired by Makefile where user-defined functions >> are referenced by $(call func-name, args...), but I omitted the 'call' >> to makes it shorter. >> >> The macro definition can contain $(1), $(2), ... which will be replaced >> with arguments from the caller. The macro works just as a textual >> shorthand, which is also expanded in the lexer phase. >> >> [Example Code] >> >> macro success $(shell ($(1) && echo y) || echo n) >> >> config TRUE >> bool "true" >> default $(success true) >> >> config FALSE >> bool "false" >> default $(success false) >> >> [Result] >> >> $ make -s alldefconfig >> $ tail -n 2 .config >> CONFIG_TRUE=y >> # CONFIG_FALSE is not set >> >> [Example Code] >> >> macro success $(shell ($(1) && echo y) || echo n) >> >> macro cc-option $(success $CC -Werror $(1) -c -x c /dev/null -o /dev/null) >> >> config CC_HAS_STACKPROTECTOR >> def_bool $(cc-option -fstack-protector) >> >> [Result] >> $ make -s alldefconfig >> $ tail -n 1 .config >> CONFIG_CC_HAS_STACKPROTECTOR=y >> >> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com> >> --- >> >> Reminder for myself: >> Update Documentation/kbuild/kconfig-language.txt >> >> Changes in v2: >> - Use 'macro' directly instead of inside the string type symbol. >> >> scripts/kconfig/function.c | 59 +++++++++++++++++++++++++++++++++++++++++++-- >> scripts/kconfig/lkc_proto.h | 1 + >> scripts/kconfig/zconf.l | 31 ++++++++++++++++++++++++ >> 3 files changed, 89 insertions(+), 2 deletions(-) >> >> diff --git a/scripts/kconfig/function.c b/scripts/kconfig/function.c >> index 913685f..389bb44 100644 >> --- a/scripts/kconfig/function.c >> +++ b/scripts/kconfig/function.c >> @@ -15,6 +15,7 @@ static LIST_HEAD(function_list); >> struct function { >> char *name; >> char *(*func)(struct function *f, int argc, char *argv[]); >> + char *macro; >> struct list_head node; >> }; >> >> @@ -31,7 +32,8 @@ static struct function *func_lookup(const char *name) >> } >> >> static void func_add(const char *name, >> - char *(*func)(struct function *f, int argc, char *argv[])) >> + char *(*func)(struct function *f, int argc, char *argv[]), >> + const char *macro) >> { >> struct function *f; >> >> @@ -44,6 +46,7 @@ static void func_add(const char *name, >> f = xmalloc(sizeof(*f)); >> f->name = xstrdup(name); >> f->func = func; >> + f->macro = macro ? xstrdup(macro) : NULL; >> >> list_add_tail(&f->node, &function_list); >> } >> @@ -51,6 +54,7 @@ static void func_add(const char *name, >> static void func_del(struct function *f) >> { >> list_del(&f->node); >> + free(f->macro); >> free(f->name); >> free(f); >> } >> @@ -108,6 +112,57 @@ char *func_eval_n(const char *func, size_t n) >> return res; >> } >> >> +/* run user-defined function */ >> +static char *do_macro(struct function *f, int argc, char *argv[]) >> +{ >> + char *new; >> + char *src, *p, *res; >> + size_t newlen; >> + int n; >> + >> + new = xmalloc(1); >> + *new = 0; > > new = '\0' would be consistent with the rest of the code. > >> + >> + /* >> + * This is a format string. $(1), $(2), ... must be replaced with >> + * function arguments. >> + */ >> + src = f->macro; >> + p = src; >> + >> + while ((p = strstr(p, "$("))) { >> + if (isdigit(p[2]) && p[3] == ')') { >> + n = p[2] - '0'; >> + if (n < argc) { >> + newlen = strlen(new) + (p - src) + >> + strlen(argv[n]) + 1; >> + new = xrealloc(new, newlen); >> + strncat(new, src, p - src); >> + strcat(new, argv[n]); >> + src = p + 4; >> + } > > Might be nice to warn when a macro call has missing arguments. Or just error out. There isn't even any backwards compatibility to think of, and that'd make the code even simpler. Something like this: while ((p = strstr(p, "$("))) { if (isdigit(p[2]) && p[3] == ')') { n = p[2] - '0'; if (n >= argc) *ERROR* newlen = strlen(new) + (p - src) + strlen(argv[n]) + 1; new = xrealloc(new, newlen); strncat(new, src, p - src); strcat(new, argv[n]); /* * Jump past macro parameter ("$(n)") and remember the new * position */ p += 4; src = p; } else { /* Jump past "$(" that isn't from a macro parameter */ p += 2; } } > >> + p += 2; >> + } >> + p += 2; >> + } > > I had to stare at this for a while to see how it worked. What do you > think of this tweak? > > while ((p = strstr(p, "$("))) { > if (isdigit(p[2]) && p[3] == ')') { > n = p[2] - '0'; > if (n < argc) { > newlen = strlen(new) + (p - src) + > strlen(argv[n]) + 1; > new = xrealloc(new, newlen); > strncat(new, src, p - src); > strcat(new, argv[n]); > > /* > * Jump past macro parameter ("$(n)") and remember the > * position > */ > p += 4; > src = p; > > continue; > } > } > > /* Jump past "$(" that isn't from a macro parameter */ > p += 2; > } > >> + >> + newlen = strlen(new) + strlen(src) + 1; >> + new = xrealloc(new, newlen); >> + strcat(new, src); >> + >> + res = expand_string_value(new); >> + >> + free(new); >> + >> + return res; >> +} >> + >> +/* add user-defined function (macro) */ >> +void func_add_macro(const char *name, const char *macro) >> +{ >> + func_add(name, do_macro, macro); >> +} >> + >> /* built-in functions */ >> static char *do_shell(struct function *f, int argc, char *argv[]) >> { >> @@ -157,7 +212,7 @@ static char *do_shell(struct function *f, int argc, char *argv[]) >> void func_init(void) >> { >> /* register built-in functions */ >> - func_add("shell", do_shell); >> + func_add("shell", do_shell, NULL); >> } >> >> void func_exit(void) >> diff --git a/scripts/kconfig/lkc_proto.h b/scripts/kconfig/lkc_proto.h >> index 09a4f53..48699c0 100644 >> --- a/scripts/kconfig/lkc_proto.h >> +++ b/scripts/kconfig/lkc_proto.h >> @@ -50,6 +50,7 @@ const char * prop_get_type_name(enum prop_type type); >> >> /* function.c */ >> char *func_eval_n(const char *func, size_t n); >> +void func_add_macro(const char *name, const char *macro); >> void func_init(void); >> void func_exit(void); >> >> diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l >> index 551ca47..6a18c68 100644 >> --- a/scripts/kconfig/zconf.l >> +++ b/scripts/kconfig/zconf.l >> @@ -74,6 +74,36 @@ static void warn_ignored_character(char chr) >> "%s:%d:warning: ignoring unsupported character '%c'\n", >> zconf_curname(), zconf_lineno(), chr); >> } >> + >> +static void handle_macro(const char *text) >> +{ >> + char *p, *q; >> + >> + while (isspace(*text)) >> + text++; >> + >> + p = xstrdup(text); >> + >> + q = p; >> + while (isalnum(*q) || *q == '_' || *q == '-') >> + q++; >> + >> + if (q == p || !*q) { >> + yyerror("invalid\n"); >> + goto free; >> + } >> + >> + *q = '\0'; >> + >> + q++; >> + while (isspace(*q)) >> + q++; >> + >> + func_add_macro(p, q); >> +free: >> + free(p); >> +} >> + >> %} >> >> n [A-Za-z0-9_-] >> @@ -82,6 +112,7 @@ n [A-Za-z0-9_-] >> int str = 0; >> int ts, i; >> >> +"macro"[ \t].* handle_macro(yytext + 6); >> [ \t]*#.*\n | >> [ \t]*\n { >> return T_EOL; >> -- >> 2.7.4 >> > > Cheers, > Ulf
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