2018-04-01 11:27 GMT+09:00 Ulf Magnusson <ulfalizer@xxxxxxxxx>: > Here's a more in-depth review: > > On Tue, Mar 27, 2018 at 7:29 AM, Masahiro Yamada > <yamada.masahiro@xxxxxxxxxxxxx> 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', > > "Environment variables" would be clearer. I've never seen them called > "environments". > >> '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 '$' is encountered, > > s/environments/environment variables/ > >> it is expanded, and resulted strings are pushed back to the input >> stream. This makes the implementation simpler. >> >> For example, the following code works. >> >> [Example code] >> >> config TOOLCHAIN_LIST >> string >> default "My tools: CC=$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@xxxxxxxxxxxxx> >> --- >> >> 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). >> - > > The new behavior needs to be documented later as well (but iirc you > already mentioned that somewhere else). > >> - "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@xxxxxxxxxxxxx> >> + >> +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; >> +} > > This function might be unnecessary -- see below. > >> + >> +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) > > This function is basically just getenv() with some dependency > housekeeping added. A name like env_get() or env_lookup() would be > clearer I think. > >> +{ >> + struct env *e; >> + const char *value; >> + > >> + e = env_list_lookup(name); >> + if (e) >> + return xstrdup(e->value); > > Not sure this bit is needed. It is always safe to get the value from > getenv(). See below. > >> + >> + value = getenv(name); >> + if (!value) { >> + fprintf(stderr, "environment variable \"%s\" undefined\n", name); >> + value = ""; >> + } >> + >> + /* >> + * we need to remember all referenced environments. > > s/environments/environment variables/ > >> + * They will be written out to include/config/auto.conf.cmd >> + */ >> + env_list_add(name, value); > > AFAICS, we only need the following functionality: > > 1. Record referenced environment variables along with their value > > 2. Go through all the recorded environment variables and write > dependency information > > For (1), I think it would be better to simply have env_list_add() (or > some other suitable name) add the variable to the list if it isn't > already there (like a kind of set). It is always safe to get the value > of the environment variable from getenv(), and that seems less > confusing. I think this is a cached value for frequently referenced environment variable such as $(CC), $(srctree). >> + >> + return xstrdup(value); > > The returned string is never modified, and the result from getenv() > never gets stale, so I think the strdup() is unnecessary. The function > could return a const char * to avoid accidental modification. The expanded text is always freed when done. This simplifies the implementation. If X is defined as X = $(shell echo ABC) The result of $(X) is an allocated string, which must be freed later. If X is an environment variable, we could handle it as a read-only string, but we are not allowed to free it. If we do not do strdup(), we need to remember where it came from. -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
