locale: New module for glibc locale_t ABI compat

CHANGELOG.rst

@@ -11,6 +11,14 @@
 0.9.0 (2020-07-??)
 ==================
 
+locale
+------
+
+* New module.
+
+* Adds newlocale and freelocale, which provide a glibc-compatible locale_t ABI.
+  This is necessary for software using the libstdc++ <locale>/<ctype> modules.
+
 unistd
 ------
 

Makefile

@@ -10,6 +10,7 @@ LIBGCOMPAT_SRC = \
 	libgcompat/gnulib.c		\
 	libgcompat/grp.c		\
 	libgcompat/internal.c		\
+	libgcompat/locale.c		\
 	libgcompat/malloc.c		\
 	libgcompat/math.c		\
 	libgcompat/misc.c		\

libgcompat/locale.c

+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include "internal.h"
+
+void *__newlocale(int, const char *, void *);
+void __freelocale(void *);
+
+struct glibc_locale {
+	/* hopefully nobody pokes at this */
+	void *__locales[13];
+
+	const unsigned short int *__ctype_b;
+	const int *__ctype_tolower;
+	const int *__ctype_toupper;
+
+	const char *__names[13];
+};
+
+const unsigned short **__ctype_b_loc(void);
+const int32_t **__ctype_tolower_loc(void);
+const int32_t **__ctype_toupper_loc(void);
+
+const char *__gcompat_valid_locales[] = {"C", "POSIX"};
+
+bool _is_valid_locale(const char *candidate) {
+	for(int i = 0; i < sizeof __gcompat_valid_locales; i++) {
+		if(strcmp(candidate, __gcompat_valid_locales[i]) == 0) return true;
+	}
+	return false;
+}
+
+struct glibc_locale *newlocale(int mask, const char *name, locale_t base) {
+	GCOMPAT__assert_with_reason(_is_valid_locale(name),
+			"locale %s not supported\n", name);
+	struct glibc_locale *ret = malloc(sizeof(struct glibc_locale));
+	if(ret == NULL) return NULL;
+
+	ret->__locales[0] = __newlocale(mask, name, base);
+	for(int l = 1; l < 13; l++) ret->__locales[l] = ret->__locales[0];
+	ret->__ctype_b = *__ctype_b_loc();
+	ret->__ctype_tolower = *__ctype_tolower_loc();
+	ret->__ctype_toupper = *__ctype_toupper_loc();
+
+	ret->__names[0] = strdup("C");
+	for(int i = 1; i < 13; i++) ret->__names[i] = ret->__names[0];
+
+	return ret;
+}
+
+void freelocale(struct glibc_locale *loc) {
+	free(loc->__names[0]);
+	__freelocale(loc->__locales[0]);
+	free(loc);
+}