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#include <dlfcn.h>
#include <stdlib.h>
#include <stdarg.h>
#include "pthread_impl.h"
#include "dynlink.h"
#include "atomic.h"
#define malloc __libc_malloc
#define calloc __libc_calloc
#define realloc __libc_realloc
#define free __libc_free
char *dlerror()
{
pthread_t self = __pthread_self();
if (!self->dlerror_flag) return 0;
self->dlerror_flag = 0;
char *s = self->dlerror_buf;
if (s == (void *)-1)
return "Dynamic linker failed to allocate memory for error message";
else
return s;
}
/* Atomic singly-linked list, used to store list of thread-local dlerror
* buffers for deferred free. They cannot be freed at thread exit time
* because, by the time it's known they can be freed, the exiting thread
* is in a highly restrictive context where it cannot call (even the
* libc-internal) free. It also can't take locks; thus the atomic list. */
static void *volatile freebuf_queue;
void __dl_thread_cleanup(void)
{
pthread_t self = __pthread_self();
if (!self->dlerror_buf || self->dlerror_buf == (void *)-1)
return;
void *h;
do {
h = freebuf_queue;
*(void **)self->dlerror_buf = h;
} while (a_cas_p(&freebuf_queue, h, self->dlerror_buf) != h);
}
hidden void __dl_vseterr(const char *fmt, va_list ap)
{
void **q;
do q = freebuf_queue;
while (q && a_cas_p(&freebuf_queue, q, 0) != q);
while (q) {
void **p = *q;
free(q);
q = p;
}
va_list ap2;
va_copy(ap2, ap);
pthread_t self = __pthread_self();
if (self->dlerror_buf != (void *)-1)
free(self->dlerror_buf);
size_t len = vsnprintf(0, 0, fmt, ap2);
if (len < sizeof(void *)) len = sizeof(void *);
va_end(ap2);
char *buf = malloc(len+1);
if (buf) {
vsnprintf(buf, len+1, fmt, ap);
} else {
buf = (void *)-1;
}
self->dlerror_buf = buf;
self->dlerror_flag = 1;
}
hidden void __dl_seterr(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
__dl_vseterr(fmt, ap);
va_end(ap);
}
static int stub_invalid_handle(void *h)
{
__dl_seterr("Invalid library handle %p", (void *)h);
return 1;
}
weak_alias(stub_invalid_handle, __dl_invalid_handle);
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