--- /dev/null
+/*******************************************************************************
+ Copyright (c) 2018, Michael Wallner <mike@php.net>.
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+ this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+ FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*******************************************************************************/
+
+#ifndef PSI_DLSYM_H
+#define PSI_DLSYM_H
+
+#include <stddef.h>
+#include <dlfcn.h>
+
+#ifndef RTLD_NEXT
+# define RTLD_NEXT ((void *) -1l)
+#endif
+#ifndef RTLD_DEFAULT
+# define RTLD_DEFAULT ((void *) 0)
+#endif
+
+#include "plist.h"
+
+static inline void *psi_dlsym(struct psi_plist *dllist, const char *name, const char *redir)
+{
+ void *dl, *sym = NULL;
+ const char *test = redir ?: name;
+
+again:
+ if (dllist) {
+ size_t i = 0;
+
+ while (!sym && psi_plist_get(dllist, i++, &dl)) {
+ sym = dlsym(dl, test);
+ }
+ }
+ if (!sym) {
+ sym = dlsym(RTLD_DEFAULT, test);
+ }
+ if (!sym && test == redir) {
+ test = name;
+ goto again;
+ }
+
+ return sym;
+}
+
+static inline size_t psi_dlname(char (*buf)[], size_t *len, const char *libname)
+{
+ if (strchr(libname, '/')) {
+ return snprintf(*buf, *len, "%s", libname);
+ } else {
+ return snprintf(*buf, *len, "lib%s.%s", libname, PHP_PSI_SHLIB_SUFFIX);
+ }
+}
+
+static inline void *psi_dlopen(const char *libname)
+{
+ return dlopen(libname, RTLD_LAZY | RTLD_LOCAL);
+}
+
+static inline void psi_dlclose(void *dl)
+{
+ dlclose(dl);
+}
+
+static inline char *psi_dlerror()
+{
+ return dlerror();
+}
+
+#endif /* PSI_DLSYM_H */