Fix: work-around glibc lying about dlsym()/dlerror() leafness

[lttng-ust.git] / include / lttng / ust-dlfcn.h

diff --git a/include/lttng/ust-dlfcn.h b/include/lttng/ust-dlfcn.h
new file mode 100644 (file)
index 0000000..786d3b5
--- /dev/null
+++ b/include/lttng/ust-dlfcn.h
@@ -0,0 +1,61 @@
+#ifndef _LTTNG_UST_DLFCN_H
+#define _LTTNG_UST_DLFCN_H
+
+/*
+ * lttng/ust-dlfcn.h
+ *
+ * Copyright 2014 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * dlfcn.h compatibility layer.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifdef _DLFCN_H
+#error "Please include lttng/ust-dlfcn.h before dlfcn.h."
+#endif /* _DLFCN_H */
+
+/*
+ * glibc declares dlsym() and dlerror() with __attribute__((leaf)) (see
+ * THROW annotation). Unfortunately, this is not in sync with reality,
+ * as those functions call the memory allocator. Work-around this glibc
+ * bug by declaring our own symbols.
+ *
+ * There has been a similar issue for dlopen() and dlclose(), as
+ * constructors and destructors are called from these functions, so they
+ * are clearly non-leaf. Work-around the issue for those too for older
+ * glibc where these have not been fixed.
+ */
+#define dlopen glibc_dlopen_proto_lies_about_leafness
+#define dlclose glibc_dlclose_proto_lies_about_leafness
+#define dlsym glibc_dlsym_proto_lies_about_leafness
+#define dlerror glibc_dlerror_proto_lies_about_leafness
+#include <dlfcn.h>
+#undef dlerror
+#undef dlsym
+#undef dlclose
+#undef dlopen
+
+extern void *dlopen(__const char *__file, int __mode);
+extern int dlclose(void *__handle) __nonnull ((1));
+extern void *dlsym(void *__restrict __handle,
+               __const char *__restrict __name) __nonnull ((2));
+extern char *dlerror (void);
+
+#endif /* _LTTNG_UST_DLFCN_H */