| #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); |