implement locale file loading and state for remaining locale categories

there is still no code which actually uses the loaded locale files, so
the main observable effect of this commit is that calls to setlocale
store and give back the names of the selected locales for the
remaining categories (LC_TIME, LC_COLLATE, LC_MONETARY) if a locale
file by the requested name could be loaded.

src/internal/libc.h

@@ -5,9 +5,12 @@
 #include <stdio.h>
 #include <limits.h>
 
+struct __locale_map;
+
 struct __locale_struct {
 	int ctype_utf8;
 	char *messages_name;
+	struct __locale_map *cat[4];
 };
 
 struct __libc {

src/internal/locale_impl.h

@@ -5,6 +5,13 @@
 
 #define LOCALE_NAME_MAX 15
 
+struct __locale_map {
+	const void *map;
+	size_t map_size;
+	char name[LOCALE_NAME_MAX+1];
+	struct __locale_map *next;
+};
+
 int __setlocalecat(locale_t, int, const char *);
 
 #define CURRENT_LOCALE \

src/locale/__setlocalecat.c

@@ -4,6 +4,58 @@
 #include "libc.h"
 #include "atomic.h"
 
+const unsigned char *__map_file(const char *, size_t *);
+int __munmap(void *, size_t);
+char *__strchrnul(const char *, int);
+
+static struct __locale_map *findlocale(const char *name, size_t n)
+{
+	static void *loc_head;
+	struct __locale_map *p, *new, *old_head;
+	const char *path = 0, *z;
+	char buf[256];
+	size_t l;
+	const void *map;
+	size_t map_size;
+
+	for (p=loc_head; p; p=p->next)
+		if (!strcmp(name, p->name)) return p;
+
+	if (strchr(name, '/')) return 0;
+
+	if (!libc.secure) path = getenv("MUSL_LOCPATH");
+	/* FIXME: add a default path? */
+	if (!path) return 0;
+
+	for (; *path; path=z+!!*z) {
+		z = __strchrnul(path, ':');
+		l = z - path - !!*z;
+		if (l >= sizeof buf - n - 2) continue;
+		memcpy(buf, path, l);
+		buf[l] = '/';
+		memcpy(buf+l+1, name, n);
+		buf[l+1+n] = 0;
+		map = __map_file(buf, &map_size);
+		if (map) {
+			new = malloc(sizeof *new);
+			if (!new) {
+				__munmap((void *)map, map_size);
+				return 0;
+			}
+			new->map = map;
+			new->map_size = map_size;
+			memcpy(new->name, name, n);
+			new->name[n] = 0;
+			do {
+				old_head = loc_head;
+				new->next = old_head;
+			} while (a_cas_p(&loc_head, old_head, new) != old_head);
+			return new;
+		}
+	}
+	return 0;
+}
+
 static const char envvars[][12] = {
 	"LC_CTYPE",
 	"LC_NUMERIC",
@@ -26,6 +78,7 @@ int __setlocalecat(locale_t loc, int cat, const char *val)
 	int builtin = (val[0]=='C' && !val[1])
 		|| !strcmp(val, "C.UTF-8")
 		|| !strcmp(val, "POSIX");
+	struct __locale_map *data, *old;
 
 	switch (cat) {
 	case LC_CTYPE:
@@ -40,6 +93,11 @@ int __setlocalecat(locale_t loc, int cat, const char *val)
 		}
 		/* fall through */
 	default:
+		data = builtin ? 0 : findlocale(val, n);
+		if (data == loc->cat[cat-2]) break;
+		do old = loc->cat[cat-2];
+		while (a_cas_p(&loc->cat[cat-2], old, data) != old);
+	case LC_NUMERIC:
 		break;
 	}
 	return 0;

src/locale/setlocale.c

@@ -9,6 +9,9 @@ static char buf[2+4*(LOCALE_NAME_MAX+1)];
 
 char *setlocale(int cat, const char *name)
 {
+	struct __locale_map *lm;
+	int i, j;
+
 	if (!libc.global_locale.messages_name) {
 		libc.global_locale.messages_name =
 			buf + 2 + 3*(LOCALE_NAME_MAX+1);
@@ -24,7 +27,6 @@ char *setlocale(int cat, const char *name)
 	if (cat == LC_ALL) {
 		if (name) {
 			char part[LOCALE_NAME_MAX+1];
-			int i, j;
 			if (name[0] && name[1]==';'
 			    && strlen(name) > 2 + 3*(LOCALE_NAME_MAX+1)) {
 				part[0] = name[0];
@@ -45,6 +47,11 @@ char *setlocale(int cat, const char *name)
 		}
 		memset(buf, ';', 2 + 3*(LOCALE_NAME_MAX+1));
 		buf[0] = libc.global_locale.ctype_utf8 ? 'U' : 'C';
+		for (i=LC_TIME; i<LC_MESSAGES; i++) {
+			lm = libc.global_locale.cat[i-2];
+			if (lm) memcpy(buf + 2 + (i-2)*(LOCALE_NAME_MAX+1),
+				lm->name, strlen(lm->name));
+		}
 		return buf;
 	}
 
@@ -58,10 +65,13 @@ char *setlocale(int cat, const char *name)
 	switch (cat) {
 	case LC_CTYPE:
 		return libc.global_locale.ctype_utf8 ? "C.UTF-8" : "C";
+	case LC_NUMERIC:
+		return "C";
 	case LC_MESSAGES:
 		return libc.global_locale.messages_name[0]
 			? libc.global_locale.messages_name : "C";
 	default:
-		return "C";
+		lm = libc.global_locale.cat[cat-2];
+		return lm ? lm->name : "C";
 	}
 }