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SubjectRe: [PATCH v2 04/21] kconfig: reference environments directly and remove 'option env=' syntax
On Thu, Mar 29, 2018 at 4:56 AM, Ulf Magnusson <ulfalizer@gmail.com> wrote:
> On Thu, Mar 29, 2018 at 4:19 AM, Ulf Magnusson <ulfalizer@gmail.com> wrote:
>> I've been kinda busy lately, so that's why I disappeared.
>>
>> I'll try to go over this patchset in more detail over the weekend.
>>
>> On Tue, Mar 27, 2018 at 7:29 AM, Masahiro Yamada
>> <yamada.masahiro@socionext.com> wrote:
>>> To get an environment value, Kconfig needs to define a symbol using
>>> "option env=" syntax. It is tedious to add a config entry for each
>>> environment given that we need more environments such as 'CC', 'AS',
>>> 'srctree' etc. to evaluate the compiler capability in Kconfig.
>>>
>>> Adding '$' to symbols is weird. Kconfig can reference symbols directly
>>> like this:
>>>
>>> config FOO
>>> string
>>> default BAR
>>>
>>> So, I want to use the following syntax to get environment 'BAR' from
>>> the system:
>>>
>>> config FOO
>>> string
>>> default $BAR
>>>
>>> Looking at the code, the symbols prefixed with 'S' are expanded by:
>>> - conf_expand_value()
>>> This is used to expand 'arch/$ARCH/defconfig' and 'defconfig_list'
>>> - expand_string_value()
>>> This is used to expand strings in 'source' and 'mainmenu'
>>>
>>> All of them are fixed values independent of user configuration. So,
>>> this kind of syntax should be moved to simply take the environment.
>>>
>>> This change makes the code much cleaner. The bounce symbols 'SRCARCH',
>>> 'ARCH', 'SUBARCH', 'KERNELVERSION' are gone.
>>>
>>> sym_init() hard-coding 'UNAME_RELEASE' is also gone. 'UNAME_RELEASE'
>>> should be be given from the environment.
>>>
>>> ARCH_DEFCONFIG is a normal symbol, so it should be simply referenced
>>> by 'default ARCH_DEFCONFIG'.
>>>
>>> The environments are expanding in the lexer; when '$' is encountered,
>>> it is expanded, and resulted strings are pushed back to the input
>>> stream. This makes the implementation simpler.
>>>
>>> For example, the following code works.
>>>
>>> [Example code]
>>>
>>> config TOOLCHAIN_LIST
>>> string
>>> default "My tools: CC=$CC, AS=$AS, CPP=$CPP"
>>>
>>> [Result]
>>>
>>> $ make -s alldefconfig && tail -n 1 .config
>>> CONFIG_TOOLCHAIN_LIST="My tools: CC=gcc, AS=as, CPP=gcc -E"
>>>
>>> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
>>> ---
>>>
>>> I tested all 'make *config' for arch architectures.
>>> I confirmed this commit still produced the same result
>>> (by my kconfig test tool).
>>>
>>>
>>> Changes in v2:
>>> - Move the string expansion to the lexer phase.
>>> - Split environment helpers to env.c
>>>
>>> Documentation/kbuild/kconfig-language.txt | 8 ---
>>> Kconfig | 4 --
>>> Makefile | 3 +-
>>> arch/sh/Kconfig | 4 +-
>>> arch/sparc/Kconfig | 4 +-
>>> arch/tile/Kconfig | 2 +-
>>> arch/um/Kconfig.common | 4 --
>>> arch/x86/Kconfig | 4 +-
>>> arch/x86/um/Kconfig | 4 +-
>>> init/Kconfig | 10 +---
>>> scripts/kconfig/confdata.c | 31 +---------
>>> scripts/kconfig/env.c | 95 +++++++++++++++++++++++++++++++
>>> scripts/kconfig/kconf_id.c | 1 -
>>> scripts/kconfig/lkc.h | 8 +--
>>> scripts/kconfig/menu.c | 3 -
>>> scripts/kconfig/symbol.c | 56 ------------------
>>> scripts/kconfig/util.c | 75 ++++++++----------------
>>> scripts/kconfig/zconf.l | 20 ++++++-
>>> scripts/kconfig/zconf.y | 2 +-
>>> 19 files changed, 158 insertions(+), 180 deletions(-)
>>> create mode 100644 scripts/kconfig/env.c
>>>
>>> diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt
>>> index f5b9493..0e966e8 100644
>>> --- a/Documentation/kbuild/kconfig-language.txt
>>> +++ b/Documentation/kbuild/kconfig-language.txt
>>> @@ -198,14 +198,6 @@ applicable everywhere (see syntax).
>>> enables the third modular state for all config symbols.
>>> At most one symbol may have the "modules" option set.
>>>
>>> - - "env"=<value>
>>> - This imports the environment variable into Kconfig. It behaves like
>>> - a default, except that the value comes from the environment, this
>>> - also means that the behaviour when mixing it with normal defaults is
>>> - undefined at this point. The symbol is currently not exported back
>>> - to the build environment (if this is desired, it can be done via
>>> - another symbol).
>>> -
>>> - "allnoconfig_y"
>>> This declares the symbol as one that should have the value y when
>>> using "allnoconfig". Used for symbols that hide other symbols.
>>> diff --git a/Kconfig b/Kconfig
>>> index 8c4c1cb..e6ece5b 100644
>>> --- a/Kconfig
>>> +++ b/Kconfig
>>> @@ -5,8 +5,4 @@
>>> #
>>> mainmenu "Linux/$ARCH $KERNELVERSION Kernel Configuration"
>>>
>>> -config SRCARCH
>>> - string
>>> - option env="SRCARCH"
>>> -
>>> source "arch/$SRCARCH/Kconfig"
>>> diff --git a/Makefile b/Makefile
>>> index 5c395ed..4ae1486 100644
>>> --- a/Makefile
>>> +++ b/Makefile
>>> @@ -284,7 +284,8 @@ include scripts/Kbuild.include
>>> # Read KERNELRELEASE from include/config/kernel.release (if it exists)
>>> KERNELRELEASE = $(shell cat include/config/kernel.release 2> /dev/null)
>>> KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
>>> -export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
>>> +UNAME_RELEASE := $(shell uname --release)
>>> +export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION UNAME_RELEASE
>>>
>>> # SUBARCH tells the usermode build what the underlying arch is. That is set
>>> # first, and if a usermode build is happening, the "ARCH=um" on the command
>>> diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
>>> index 97fe293..14f3ef1 100644
>>> --- a/arch/sh/Kconfig
>>> +++ b/arch/sh/Kconfig
>>> @@ -57,7 +57,7 @@ config SUPERH
>>> <http://www.linux-sh.org/>.
>>>
>>> config SUPERH32
>>> - def_bool ARCH = "sh"
>>> + def_bool "$ARCH" = "sh"
>>> select HAVE_KPROBES
>>> select HAVE_KRETPROBES
>>> select HAVE_IOREMAP_PROT if MMU && !X2TLB
>>> @@ -76,7 +76,7 @@ config SUPERH32
>>> select HAVE_CC_STACKPROTECTOR
>>>
>>> config SUPERH64
>>> - def_bool ARCH = "sh64"
>>> + def_bool "$ARCH" = "sh64"
>>> select HAVE_EXIT_THREAD
>>> select KALLSYMS
>>>
>>> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
>>> index 8767e45..86b852e 100644
>>> --- a/arch/sparc/Kconfig
>>> +++ b/arch/sparc/Kconfig
>>> @@ -1,6 +1,6 @@
>>> config 64BIT
>>> - bool "64-bit kernel" if ARCH = "sparc"
>>> - default ARCH = "sparc64"
>>> + bool "64-bit kernel" if "$ARCH" = "sparc"
>>> + default "$ARCH" = "sparc64"
>>> help
>>> SPARC is a family of RISC microprocessors designed and marketed by
>>> Sun Microsystems, incorporated. They are very widely found in Sun
>>> diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
>>> index ef9d403..acc2182 100644
>>> --- a/arch/tile/Kconfig
>>> +++ b/arch/tile/Kconfig
>>> @@ -119,7 +119,7 @@ config HVC_TILE
>>> # Building with ARCH=tilegx (or ARCH=tile) implies using the
>>> # 64-bit TILE-Gx toolchain, so force CONFIG_TILEGX on.
>>> config TILEGX
>>> - def_bool ARCH != "tilepro"
>>> + def_bool "$ARCH" != "tilepro"
>>> select ARCH_SUPPORTS_ATOMIC_RMW
>>> select GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
>>> select HAVE_ARCH_JUMP_LABEL
>>> diff --git a/arch/um/Kconfig.common b/arch/um/Kconfig.common
>>> index c68add8..07f84c8 100644
>>> --- a/arch/um/Kconfig.common
>>> +++ b/arch/um/Kconfig.common
>>> @@ -54,10 +54,6 @@ config HZ
>>> int
>>> default 100
>>>
>>> -config SUBARCH
>>> - string
>>> - option env="SUBARCH"
>>> -
>>> config NR_CPUS
>>> int
>>> range 1 1
>>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>>> index 0fa71a7..986fb0a 100644
>>> --- a/arch/x86/Kconfig
>>> +++ b/arch/x86/Kconfig
>>> @@ -1,8 +1,8 @@
>>> # SPDX-License-Identifier: GPL-2.0
>>> # Select 32 or 64 bit
>>> config 64BIT
>>> - bool "64-bit kernel" if ARCH = "x86"
>>> - default ARCH != "i386"
>>> + bool "64-bit kernel" if "$ARCH" = "x86"
>>> + default "$ARCH" != "i386"
>>> ---help---
>>> Say yes to build a 64-bit kernel - formerly known as x86_64
>>> Say no to build a 32-bit kernel - formerly known as i386
>>> diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
>>> index 13ed827..d355413 100644
>>> --- a/arch/x86/um/Kconfig
>>> +++ b/arch/x86/um/Kconfig
>>> @@ -16,8 +16,8 @@ config UML_X86
>>> select GENERIC_FIND_FIRST_BIT
>>>
>>> config 64BIT
>>> - bool "64-bit kernel" if SUBARCH = "x86"
>>> - default SUBARCH != "i386"
>>> + bool "64-bit kernel" if $SUBARCH = "x86"
>>> + default $SUBARCH != "i386"
>>>
>>> config X86_32
>>> def_bool !64BIT
>>> diff --git a/init/Kconfig b/init/Kconfig
>>> index df18492..b4814e6 100644
>>> --- a/init/Kconfig
>>> +++ b/init/Kconfig
>>> @@ -1,11 +1,3 @@
>>> -config ARCH
>>> - string
>>> - option env="ARCH"
>>> -
>>> -config KERNELVERSION
>>> - string
>>> - option env="KERNELVERSION"
>>> -
>>> config DEFCONFIG_LIST
>>> string
>>> depends on !UML
>>> @@ -13,7 +5,7 @@ config DEFCONFIG_LIST
>>> default "/lib/modules/$UNAME_RELEASE/.config"
>>> default "/etc/kernel-config"
>>> default "/boot/config-$UNAME_RELEASE"
>>> - default "$ARCH_DEFCONFIG"
>>> + default ARCH_DEFCONFIG
>>> default "arch/$ARCH/defconfig"
>>>
>>> config CONSTRUCTORS
>>> diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
>>> index df26c7b..98c2014 100644
>>> --- a/scripts/kconfig/confdata.c
>>> +++ b/scripts/kconfig/confdata.c
>>> @@ -81,39 +81,13 @@ const char *conf_get_autoconfig_name(void)
>>> return name ? name : "include/config/auto.conf";
>>> }
>>>
>>> -static char *conf_expand_value(const char *in)
>>> -{
>>> - struct symbol *sym;
>>> - const char *src;
>>> - static char res_value[SYMBOL_MAXLENGTH];
>>> - char *dst, name[SYMBOL_MAXLENGTH];
>>> -
>>> - res_value[0] = 0;
>>> - dst = name;
>>> - while ((src = strchr(in, '$'))) {
>>> - strncat(res_value, in, src - in);
>>> - src++;
>>> - dst = name;
>>> - while (isalnum(*src) || *src == '_')
>>> - *dst++ = *src++;
>>> - *dst = 0;
>>> - sym = sym_lookup(name, 0);
>>> - sym_calc_value(sym);
>>> - strcat(res_value, sym_get_string_value(sym));
>>> - in = src;
>>> - }
>>> - strcat(res_value, in);
>>> -
>>> - return res_value;
>>> -}
>>> -
>>> char *conf_get_default_confname(void)
>>> {
>>> struct stat buf;
>>> static char fullname[PATH_MAX+1];
>>> char *env, *name;
>>>
>>> - name = conf_expand_value(conf_defname);
>>> + name = expand_string_value(conf_defname);
>>> env = getenv(SRCTREE);
>>> if (env) {
>>> sprintf(fullname, "%s/%s", env, name);
>>> @@ -274,7 +248,8 @@ int conf_read_simple(const char *name, int def)
>>> if (expr_calc_value(prop->visible.expr) == no ||
>>> prop->expr->type != E_SYMBOL)
>>> continue;
>>> - name = conf_expand_value(prop->expr->left.sym->name);
>>> + sym_calc_value(prop->expr->left.sym);
>>> + name = sym_get_string_value(prop->expr->left.sym);
>>> in = zconf_fopen(name);
>>> if (in) {
>>> conf_message(_("using defaults found in %s"),
>>> diff --git a/scripts/kconfig/env.c b/scripts/kconfig/env.c
>>> new file mode 100644
>>> index 0000000..9702f5c
>>> --- /dev/null
>>> +++ b/scripts/kconfig/env.c
>>> @@ -0,0 +1,95 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +//
>>> +// Copyright (C) 2018 Masahiro Yamada <yamada.masahiro@socionext.com>
>>> +
>>> +static LIST_HEAD(env_list);
>>> +
>>> +struct env {
>>> + char *name;
>>> + char *value;
>>> + struct list_head node;
>>> +};
>>> +
>>> +static struct env *env_list_lookup(const char *name)
>>> +{
>>> + struct env *e;
>>> +
>>> + list_for_each_entry(e, &env_list, node) {
>>> + if (!strcmp(name, e->name))
>>> + return e;
>>> + }
>>> +
>>> + return NULL;
>>> +}
>>> +
>>> +static void env_list_add(const char *name, const char *value)
>>> +{
>>> + struct env *e;
>>> +
>>> + e = xmalloc(sizeof(*e));
>>> + e->name = xstrdup(name);
>>> + e->value = xstrdup(value);
>>> +
>>> + list_add_tail(&e->node, &env_list);
>>> +}
>>> +
>>> +static void env_list_del(struct env *e)
>>> +{
>>> + list_del(&e->node);
>>> + free(e->name);
>>> + free(e->value);
>>> + free(e);
>>> +}
>>> +
>>> +/* the returned pointer must be freed when done */
>>> +static char *env_expand(const char *name)
>>> +{
>>> + struct env *e;
>>> + const char *value;
>>> +
>>> + e = env_list_lookup(name);
>>> + if (e)
>>> + return xstrdup(e->value);
>>> +
>>> + value = getenv(name);
>>> + if (!value) {
>>> + fprintf(stderr, "environment variable \"%s\" undefined\n", name);
>>> + value = "";
>>> + }
>>> +
>>> + /*
>>> + * we need to remember all referenced environments.
>>> + * They will be written out to include/config/auto.conf.cmd
>>> + */
>>> + env_list_add(name, value);
>>> +
>>> + return xstrdup(value);
>>> +}
>>> +
>>> +/* works like env_expand, but 'name' does not need to be null-terminated */
>>> +char *env_expand_n(const char *name, size_t n)
>>> +{
>>> + char *tmp, *res;
>>> +
>>> + tmp = xmalloc(n + 1);
>>> + memcpy(tmp, name, n);
>>> + *(tmp + n) = '\0';
>>> +
>>> + res = env_expand(tmp);
>>> +
>>> + free(tmp);
>>> +
>>> + return res;
>>> +}
>>> +
>>> +void env_write_dep(FILE *f, const char *autoconfig_name)
>>> +{
>>> + struct env *env, *tmp;
>>> +
>>> + list_for_each_entry_safe(env, tmp, &env_list, node) {
>>> + fprintf(f, "ifneq \"$(%s)\" \"%s\"\n", env->name, env->value);
>>> + fprintf(f, "%s: FORCE\n", autoconfig_name);
>>> + fprintf(f, "endif\n");
>>> + env_list_del(env);
>>> + }
>>> +}
>>> diff --git a/scripts/kconfig/kconf_id.c b/scripts/kconfig/kconf_id.c
>>> index 3ea9c5f..b3e0ea0 100644
>>> --- a/scripts/kconfig/kconf_id.c
>>> +++ b/scripts/kconfig/kconf_id.c
>>> @@ -32,7 +32,6 @@ static struct kconf_id kconf_id_array[] = {
>>> { "on", T_ON, TF_PARAM },
>>> { "modules", T_OPT_MODULES, TF_OPTION },
>>> { "defconfig_list", T_OPT_DEFCONFIG_LIST, TF_OPTION },
>>> - { "env", T_OPT_ENV, TF_OPTION },
>>> { "allnoconfig_y", T_OPT_ALLNOCONFIG_Y, TF_OPTION },
>>> };
>>>
>>> diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
>>> index c8d9e55..03d007f 100644
>>> --- a/scripts/kconfig/lkc.h
>>> +++ b/scripts/kconfig/lkc.h
>>> @@ -58,7 +58,6 @@ enum conf_def_mode {
>>>
>>> #define T_OPT_MODULES 1
>>> #define T_OPT_DEFCONFIG_LIST 2
>>> -#define T_OPT_ENV 3
>>> #define T_OPT_ALLNOCONFIG_Y 4
>>>
>>> struct kconf_id {
>>> @@ -95,6 +94,10 @@ static inline void xfwrite(const void *str, size_t len, size_t count, FILE *out)
>>> fprintf(stderr, "Error in writing or end of file.\n");
>>> }
>>>
>>> +/* env.c */
>>> +char *env_expand_n(const char *name, size_t n);
>>> +void env_write_dep(FILE *f, const char *auto_conf_name);
>>> +
>>> /* menu.c */
>>> void _menu_init(void);
>>> void menu_warn(struct menu *menu, const char *fmt, ...);
>>> @@ -135,9 +138,6 @@ void str_printf(struct gstr *gs, const char *fmt, ...);
>>> const char *str_get(struct gstr *gs);
>>>
>>> /* symbol.c */
>>> -extern struct expr *sym_env_list;
>>> -
>>> -void sym_init(void);
>>> void sym_clear_all_valid(void);
>>> struct symbol *sym_choice_default(struct symbol *sym);
>>> const char *sym_get_string_default(struct symbol *sym);
>>> diff --git a/scripts/kconfig/menu.c b/scripts/kconfig/menu.c
>>> index 5c5c137..8148305 100644
>>> --- a/scripts/kconfig/menu.c
>>> +++ b/scripts/kconfig/menu.c
>>> @@ -214,9 +214,6 @@ void menu_add_option(int token, char *arg)
>>> zconf_error("trying to redefine defconfig symbol");
>>> sym_defconfig_list->flags |= SYMBOL_AUTO;
>>> break;
>>> - case T_OPT_ENV:
>>> - prop_add_env(arg);
>>> - break;
>>> case T_OPT_ALLNOCONFIG_Y:
>>> current_entry->sym->flags |= SYMBOL_ALLNOCONFIG_Y;
>>> break;
>>> diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
>>> index 03143b2..7c9a88e 100644
>>> --- a/scripts/kconfig/symbol.c
>>> +++ b/scripts/kconfig/symbol.c
>>> @@ -33,33 +33,6 @@ struct symbol *sym_defconfig_list;
>>> struct symbol *modules_sym;
>>> tristate modules_val;
>>>
>>> -struct expr *sym_env_list;
>>> -
>>> -static void sym_add_default(struct symbol *sym, const char *def)
>>> -{
>>> - struct property *prop = prop_alloc(P_DEFAULT, sym);
>>> -
>>> - prop->expr = expr_alloc_symbol(sym_lookup(def, SYMBOL_CONST));
>>> -}
>>> -
>>> -void sym_init(void)
>>> -{
>>> - struct symbol *sym;
>>> - struct utsname uts;
>>> - static bool inited = false;
>>> -
>>> - if (inited)
>>> - return;
>>> - inited = true;
>>> -
>>> - uname(&uts);
>>> -
>>> - sym = sym_lookup("UNAME_RELEASE", 0);
>>> - sym->type = S_STRING;
>>> - sym->flags |= SYMBOL_AUTO;
>>> - sym_add_default(sym, uts.release);
>>> -}
>>> -
>>> enum symbol_type sym_get_type(struct symbol *sym)
>>> {
>>> enum symbol_type type = sym->type;
>>> @@ -1348,32 +1321,3 @@ const char *prop_get_type_name(enum prop_type type)
>>> }
>>> return "unknown";
>>> }
>>> -
>>> -static void prop_add_env(const char *env)
>>> -{
>>> - struct symbol *sym, *sym2;
>>> - struct property *prop;
>>> - char *p;
>>> -
>>> - sym = current_entry->sym;
>>> - sym->flags |= SYMBOL_AUTO;
>>> - for_all_properties(sym, prop, P_ENV) {
>>> - sym2 = prop_get_symbol(prop);
>>> - if (strcmp(sym2->name, env))
>>> - menu_warn(current_entry, "redefining environment symbol from %s",
>>> - sym2->name);
>>> - return;
>>> - }
>>> -
>>> - prop = prop_alloc(P_ENV, sym);
>>> - prop->expr = expr_alloc_symbol(sym_lookup(env, SYMBOL_CONST));
>>> -
>>> - sym_env_list = expr_alloc_one(E_LIST, sym_env_list);
>>> - sym_env_list->right.sym = sym;
>>> -
>>> - p = getenv(env);
>>> - if (p)
>>> - sym_add_default(sym, p);
>>> - else
>>> - menu_warn(current_entry, "environment variable %s undefined", env);
>>> -}
>>> diff --git a/scripts/kconfig/util.c b/scripts/kconfig/util.c
>>> index 22201a4..136e497 100644
>>> --- a/scripts/kconfig/util.c
>>> +++ b/scripts/kconfig/util.c
>>> @@ -8,16 +8,18 @@
>>> #include <stdarg.h>
>>> #include <stdlib.h>
>>> #include <string.h>
>>> +
>>> +#include "list.h"
>>> #include "lkc.h"
>>>
>>> /*
>>> - * Expand symbol's names embedded in the string given in argument. Symbols'
>>> - * name to be expanded shall be prefixed by a '$'. Unknown symbol expands to
>>> + * Expand environments embedded in the string given in argument. Environments
>>> + * to be expanded shall be prefixed by a '$'. Unknown environment expands to
>>> * the empty string.
>>> */
>>> char *expand_string_value(const char *in)
>>> {
>>> - const char *src;
>>> + const char *p, *q;
>>> char *res;
>>> size_t reslen;
>>>
>>> @@ -25,39 +27,28 @@ char *expand_string_value(const char *in)
>>> * Note: 'in' might come from a token that's about to be
>>> * freed, so make sure to always allocate a new string
>>> */
>>> - reslen = strlen(in) + 1;
>>> - res = xmalloc(reslen);
>>> - res[0] = '\0';
>>> -
>>> - while ((src = strchr(in, '$'))) {
>>> - char *p, name[SYMBOL_MAXLENGTH];
>>> - const char *symval = "";
>>> - struct symbol *sym;
>>> - size_t newlen;
>>> -
>>> - strncat(res, in, src - in);
>>> - src++;
>>> -
>>> - p = name;
>>> - while (isalnum(*src) || *src == '_')
>>> - *p++ = *src++;
>>> - *p = '\0';
>>> -
>>> - sym = sym_find(name);
>>> - if (sym != NULL) {
>>> - sym_calc_value(sym);
>>> - symval = sym_get_string_value(sym);
>>> - }
>>> + res = xmalloc(1);
>>> + *res = '\0';
>>>
>>> - newlen = strlen(res) + strlen(symval) + strlen(src) + 1;
>>> - if (newlen > reslen) {
>>> - reslen = newlen;
>>> - res = xrealloc(res, reslen);
>>> - }
>>> + while ((p = strchr(in, '$'))) {
>>> + char *new;
>>> +
>>> + q = p + 1;
>>> + while (isalnum(*q) || *q == '_')
>>> + q++;
>>>
>>> - strcat(res, symval);
>>> - in = src;
>>> + new = env_expand_n(p + 1, q - p - 1);
>>> +
>>> + reslen = strlen(res) + (p - in) + strlen(new) + 1;
>>> + res = xrealloc(res, reslen);
>>> + strncat(res, in, p - in);
>>> + strcat(res, new);
>>> + free(new);
>>> + in = q;
>>> }
>>> +
>>> + reslen = strlen(res) + strlen(in) + 1;
>>> + res = xrealloc(res, reslen);
>>> strcat(res, in);
>>>
>>> return res;
>>> @@ -87,8 +78,6 @@ struct file *file_lookup(const char *name)
>>> /* write a dependency file as used by kbuild to track dependencies */
>>> int file_write_dep(const char *name)
>>> {
>>> - struct symbol *sym, *env_sym;
>>> - struct expr *e;
>>> struct file *file;
>>> FILE *out;
>>>
>>> @@ -107,21 +96,7 @@ int file_write_dep(const char *name)
>>> fprintf(out, "\n%s: \\\n"
>>> "\t$(deps_config)\n\n", conf_get_autoconfig_name());
>>>
>>> - expr_list_for_each_sym(sym_env_list, e, sym) {
>>> - struct property *prop;
>>> - const char *value;
>>> -
>>> - prop = sym_get_env_prop(sym);
>>> - env_sym = prop_get_symbol(prop);
>>> - if (!env_sym)
>>> - continue;
>>> - value = getenv(env_sym->name);
>>> - if (!value)
>>> - value = "";
>>> - fprintf(out, "ifneq \"$(%s)\" \"%s\"\n", env_sym->name, value);
>>> - fprintf(out, "%s: FORCE\n", conf_get_autoconfig_name());
>>> - fprintf(out, "endif\n");
>>> - }
>>> + env_write_dep(out, conf_get_autoconfig_name());
>>>
>>> fprintf(out, "\n$(deps_config): ;\n");
>>> fclose(out);
>>> diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
>>> index 045093d..551ca47 100644
>>> --- a/scripts/kconfig/zconf.l
>>> +++ b/scripts/kconfig/zconf.l
>>> @@ -35,6 +35,7 @@ struct buffer *current_buf;
>>>
>>> static int last_ts, first_ts;
>>>
>>> +static void expand_string(const char *in);
>>> static void zconf_endhelp(void);
>>> static void zconf_endfile(void);
>>>
>>> @@ -120,6 +121,7 @@ n [A-Za-z0-9_-]
>>> }
>>>
>>> <PARAM>{
>>> + "$".* expand_string(yytext);
>>> "&&" return T_AND;
>>> "||" return T_OR;
>>> "(" return T_OPEN_PAREN;
>>> @@ -157,12 +159,13 @@ n [A-Za-z0-9_-]
>>> }
>>>
>>> <STRING>{
>>> - [^'"\\\n]+/\n {
>>> + "$".* expand_string(yytext);
>>> + [^$'"\\\n]+/\n {
>>> append_string(yytext, yyleng);
>>> yylval.string = text;
>>> return T_WORD_QUOTE;
>>> }
>>> - [^'"\\\n]+ {
>>> + [^$'"\\\n]+ {
>>> append_string(yytext, yyleng);
>>> }
>>> \\.?/\n {
>>> @@ -249,6 +252,19 @@ n [A-Za-z0-9_-]
>>> }
>>>
>>> %%
>>> +static void expand_string(const char *in)
>>> +{
>>> + char *p, *q;
>>> +
>>> + p = expand_string_value(in);
>>> +
>>> + q = p + strlen(p);
>>> + while (q > p)
>>> + unput(*--q);
>>> +
>>> + free(p);
>>> +}
>>> +
>>
>> I like the simplicity of this approach, but I suspect it might be too simple.
>>
>> For example, the following breaks with a syntax error if $ENV has any
>> double quotes in its value:
>>
>> config FOO
>> string "foo"
>> default "$ENV"
>>
>> The following will only work as expected if $ENV expands to a valid
>> Kconfig symbol name. If it doesn't, random stuff will happen (most
>> likely a syntax error).
>>
>> config FOO
>> string "foo"
>> default $ENV
>>
>> The reason it works if $ENV expands to a valid symbol name is that
>> undefined symbols get their name as their (string) value. If the
>> symbol happens to be defined, it will be referenced, which seems
>> confusing too.
>>
>> In general, that reinterpretation of expanded values feels a bit icky
>> to me, and as something that might add complexity to Kconfig for
>> little value. If $ENV outside of quotes absolutely must be supported,
>> I think it should be a shorthand for "$ENV" (which means "constant
>> value" in Kconfig speak).
>
> If you want something as general as the C preprocessor (which I think
> would be overkill and complexity land), then it seems kinda weird to
> limit it to certain Kconfig contexts as well: Right now you'd be able
> to output arbitrary tokens inside an expression, but you couldn't do
> something like generate a 'default X if Y'.
>
> Cheers,
> Ulf

I know you're not a fan, but if expansion was limited to within
constant values (quotes), then you'd be able to handle it all by just
expanding the text before a T_WORD_QUOTE is returned. Extremely
simple, and no gotchas. ;)

Cheers,
Ulf

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