implement fail-safe static locales for newlocale

this frees applications which need to make temporary use of the C
locale (via uselocale) from the possibility that newlocale might fail.

the C.UTF-8 locale is also provided as a static locale. presently they
behave the same, but this may change in the future.

diff --git a/src/locale/freelocale.c b/src/locale/freelocale.c
index ee3f029abf5a10169ca77e9ebc0080df83464fd0..c2ae1a318069376823527d79f4b19a9e8974823e 100644 (file)
--- a/src/locale/freelocale.c
+++ b/src/locale/freelocale.c
@@ -2,9 +2,11 @@
 #include "locale_impl.h"
 #include "libc.h"
 
+int __loc_is_allocated(locale_t);
+
 void freelocale(locale_t l)
 {
-       free(l);
+       if (__loc_is_allocated(l)) free(l);
 }
 
 weak_alias(freelocale, __freelocale);

diff --git a/src/locale/locale_map.c b/src/locale/locale_map.c
index 30aa7fcc3d9595285d05ae37c795243882bddcf4..4346bb02b352bc6781c9f9a0a9b551c2f5366e35 100644 (file)
--- a/src/locale/locale_map.c
+++ b/src/locale/locale_map.c
@@ -26,7 +26,7 @@ static const char envvars[][12] = {
 
 static const uint32_t empty_mo[] = { 0x950412de, 0, -1, -1, -1 };
 
-static const struct __locale_map c_dot_utf8 = {
+const struct __locale_map __c_dot_utf8 = {
        .map = empty_mo,
        .map_size = sizeof empty_mo,
        .name = "C.UTF-8"
@@ -58,7 +58,7 @@ const struct __locale_map *__get_locale(int cat, const char *val)
 
        if (builtin) {
                if (cat == LC_CTYPE && val[1]=='.')
-                       return (void *)&c_dot_utf8;
+                       return (void *)&__c_dot_utf8;
                return 0;
        }
 
@@ -117,7 +117,7 @@ const struct __locale_map *__get_locale(int cat, const char *val)
 
        /* For LC_CTYPE, never return a null pointer unless the
         * requested name was "C" or "POSIX". */
-       if (!new && cat == LC_CTYPE) new = (void *)&c_dot_utf8;
+       if (!new && cat == LC_CTYPE) new = (void *)&__c_dot_utf8;
 
        UNLOCK(lock);
        return new;

diff --git a/src/locale/newlocale.c b/src/locale/newlocale.c
index 4e0cbd34072f23675cda75cf047dfc9fbace184d..89d36b1d72d79307e3fafdb3063951b9f27a1933 100644 (file)
--- a/src/locale/newlocale.c
+++ b/src/locale/newlocale.c
@@ -3,21 +3,52 @@
 #include "locale_impl.h"
 #include "libc.h"
 
+extern const struct __locale_map __c_dot_utf8;
+
+static const struct __locale_struct c_locale = { 0 };
+static const struct __locale_struct c_dot_utf8_locale = {
+       .cat[LC_CTYPE] = &__c_dot_utf8
+};
+
+int __loc_is_allocated(locale_t loc)
+{
+       return loc && loc != &c_locale && loc != &c_dot_utf8_locale;
+}
+
 locale_t __newlocale(int mask, const char *name, locale_t loc)
 {
-       int i;
+       int i, j;
+       struct __locale_struct tmp;
+       const struct __locale_map *lm;
 
-       if (!loc) {
-               loc = malloc(sizeof *loc);
-               if (!loc) return 0;
+       /* For locales with allocated storage, modify in-place. */
+       if (__loc_is_allocated(loc)) {
                for (i=0; i<LC_ALL; i++)
-                       if (!(mask & (1<<i)))
-                               loc->cat[i] = __get_locale(i, "");
+                       if (mask & (1<<i))
+                               loc->cat[i] = __get_locale(i, name);
+               return loc;
+       }
+
+       /* Otherwise, build a temporary locale object, which will only
+        * be instantiated in allocated storage if it does not match
+        * one of the built-in static locales. This makes the common
+        * usage case for newlocale, getting a C locale with predictable
+        * behavior, very fast, and more importantly, fail-safe. */
+       for (j=i=0; i<LC_ALL; i++) {
+               if (loc && !(mask & (1<<i)))
+                       lm = loc->cat[i];
+               else
+                       lm = __get_locale(i, mask & (1<<i) ? name : "");
+               if (lm) j++;
+               tmp.cat[i] = lm;
        }
 
-       for (i=0; i<LC_ALL; i++)
-               if (mask & (1<<i))
-                       loc->cat[i] = __get_locale(i, name);
+       if (!j)
+               return (locale_t)&c_locale;
+       if (j==1 && tmp.cat[LC_CTYPE]==c_dot_utf8_locale.cat[LC_CTYPE])
+               return (locale_t)&c_dot_utf8_locale;
+
+       if ((loc = malloc(sizeof *loc))) *loc = tmp;
 
        return loc;
 }