mirror of
https://github.com/fluencelabs/musl
synced 2025-04-24 23:02:14 +00:00
56fbaa3bbe
the memory model we use internally for atomics permits plain loads of values which may be subject to concurrent modification without requiring that a special load function be used. since a compiler is free to make transformations that alter the number of loads or the way in which loads are performed, the compiler is theoretically free to break this usage. the most obvious concern is with atomic cas constructs: something of the form tmp=*p;a_cas(p,tmp,f(tmp)); could be transformed to a_cas(p,*p,f(*p)); where the latter is intended to show multiple loads of *p whose resulting values might fail to be equal; this would break the atomicity of the whole operation. but even more fundamental breakage is possible. with the changes being made now, objects that may be modified by atomics are modeled as volatile, and the atomic operations performed on them by other threads are modeled as asynchronous stores by hardware which happens to be acting on the request of another thread. such modeling of course does not itself address memory synchronization between cores/cpus, but that aspect was already handled. this all seems less than ideal, but it's the best we can do without mandating a C11 compiler and using the C11 model for atomics. in the case of pthread_once_t, the ABI type of the underlying object is not volatile-qualified. so we are assuming that accessing the object through a volatile-qualified lvalue via casts yields volatile access semantics. the language of the C standard is somewhat unclear on this matter, but this is an assumption the linux kernel also makes, and seems to be the correct interpretation of the standard.
112 lines
2.5 KiB
C
112 lines
2.5 KiB
C
#include <locale.h>
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#include <string.h>
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#include "locale_impl.h"
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#include "libc.h"
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#include "atomic.h"
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const char *__lctrans_impl(const char *msg, const struct __locale_map *lm)
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{
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const char *trans = 0;
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if (lm) trans = __mo_lookup(lm->map, lm->map_size, msg);
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return trans ? trans : msg;
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}
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const unsigned char *__map_file(const char *, size_t *);
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int __munmap(void *, size_t);
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char *__strchrnul(const char *, int);
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static struct __locale_map *findlocale(const char *name, size_t n)
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{
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static void *volatile loc_head;
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struct __locale_map *p, *new, *old_head;
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const char *path = 0, *z;
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char buf[256];
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size_t l;
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const void *map;
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size_t map_size;
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for (p=loc_head; p; p=p->next)
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if (!strcmp(name, p->name)) return p;
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if (!libc.secure) path = getenv("MUSL_LOCPATH");
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/* FIXME: add a default path? */
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if (!path) return 0;
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for (; *path; path=z+!!*z) {
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z = __strchrnul(path, ':');
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l = z - path - !!*z;
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if (l >= sizeof buf - n - 2) continue;
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memcpy(buf, path, l);
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buf[l] = '/';
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memcpy(buf+l+1, name, n);
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buf[l+1+n] = 0;
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map = __map_file(buf, &map_size);
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if (map) {
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new = malloc(sizeof *new);
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if (!new) {
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__munmap((void *)map, map_size);
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return 0;
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}
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new->map = map;
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new->map_size = map_size;
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memcpy(new->name, name, n);
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new->name[n] = 0;
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do {
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old_head = loc_head;
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new->next = old_head;
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} while (a_cas_p(&loc_head, old_head, new) != old_head);
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return new;
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}
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}
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return 0;
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}
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static const char envvars[][12] = {
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"LC_CTYPE",
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"LC_NUMERIC",
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"LC_TIME",
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"LC_COLLATE",
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"LC_MONETARY",
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"LC_MESSAGES",
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};
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int __setlocalecat(locale_t loc, int cat, const char *val)
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{
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if (!*val) {
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(val = getenv("LC_ALL")) && *val ||
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(val = getenv(envvars[cat])) && *val ||
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(val = getenv("LANG")) && *val ||
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(val = "C.UTF-8");
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}
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size_t n;
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for (n=0; n<LOCALE_NAME_MAX && val[n] && val[n]!='/'; n++);
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if (val[0]=='.' || val[n]) val = "C.UTF-8";
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int builtin = (val[0]=='C' && !val[1])
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|| !strcmp(val, "C.UTF-8")
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|| !strcmp(val, "POSIX");
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struct __locale_map *data, *old;
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switch (cat) {
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case LC_CTYPE:
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a_store(&loc->ctype_utf8, !builtin || val[1]=='.');
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break;
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case LC_MESSAGES:
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if (builtin) {
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loc->messages_name[0] = 0;
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} else {
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memcpy(loc->messages_name, val, n);
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loc->messages_name[n] = 0;
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}
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/* fall through */
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default:
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data = builtin ? 0 : findlocale(val, n);
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if (data == loc->cat[cat-2]) break;
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do old = loc->cat[cat-2];
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while (a_cas_p(&loc->cat[cat-2], old, data) != old);
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case LC_NUMERIC:
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break;
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}
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return 0;
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}
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