third_party/ulib/musl/src/ldso/dlerror.c

#include "libc.h"
#include "threads_impl.h"
#include <dlfcn.h>
#include <stdarg.h>
#include <stdlib.h>

char* dlerror(void) {
    thrd_t self = __thrd_current();
    if (!self->dlerror_flag)
        return 0;
    self->dlerror_flag = 0;
    char* s = self->dlerror_buf;
    if (s == (void*)-1)
        return (char*)"Dynamic linker failed to allocate memory for error message";
    else
        return s;
}

void __dl_thread_cleanup(void) {
    thrd_t self = __thrd_current();
    if (self->dlerror_buf != (void*)-1)
        free(self->dlerror_buf);
}

__attribute__((__visibility__("hidden"))) void __dl_vseterr(const char* fmt, va_list ap) {
    va_list ap2;
    va_copy(ap2, ap);
    thrd_t self = __thrd_current();
    if (self->dlerror_buf != (void*)-1)
        free(self->dlerror_buf);
    size_t len = vsnprintf(0, 0, fmt, ap2);
    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;
}

__attribute__((__visibility__("hidden"))) void __dl_seterr(const char* fmt, ...) {
    va_list ap;
    va_start(ap, fmt);
    __dl_vseterr(fmt, ap);
    va_end(ap);
}

__attribute__((__visibility__("hidden"))) int __dl_invalid_handle(void*);

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);