Python/dynload_shlib.c

/***********************************************************
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
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Centrum or CWI or Corporation for National Research Initiatives or
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permission.

While CWI is the initial source for this software, a modified version
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(CNRI) at the Internet address ftp://ftp.python.org.

STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
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******************************************************************/

/* Support for dynamic loading of extension modules */

#include "Python.h"
#include "importdl.h"

#include <sys/types.h>
#include <sys/stat.h>
#if defined(__NetBSD__) && (NetBSD < 199712)
#include <nlist.h>
#include <link.h>
#define dlerror() "error in dynamic linking"
#else
#ifdef HAVE_DLFCN_H
#include <dlfcn.h>
#endif
#endif

#ifndef RTLD_LAZY
#define RTLD_LAZY 1
#endif


const struct filedescr _PyImport_DynLoadFiletab[] = {
	{".so", "rb", C_EXTENSION},
	{"module.so", "rb", C_EXTENSION},
	{0, 0}
};

static struct {
	dev_t dev;
	ino_t ino;
	void *handle;
} handles[128];
static int nhandles = 0;


dl_funcptr _PyImport_GetDynLoadFunc(const char *name, const char *funcname,
				    const char *pathname, FILE *fp)
{
	dl_funcptr p;
	void *handle;

	if (fp != NULL) {
		int i;
		struct stat statb;
		fstat(fileno(fp), &statb);
		for (i = 0; i < nhandles; i++) {
			if (statb.st_dev == handles[i].dev &&
			    statb.st_ino == handles[i].ino) {
				p = (dl_funcptr) dlsym(handles[i].handle,
						       funcname);
				return p;
			}
		}
		if (nhandles < 128) {
			handles[nhandles].dev = statb.st_dev;
			handles[nhandles].ino = statb.st_ino;
		}
	}

#ifdef RTLD_NOW
	/* RTLD_NOW: resolve externals now
	   (i.e. core dump now if some are missing) */
	handle = dlopen(pathname, RTLD_NOW);
#else
	if (Py_VerboseFlag)
		printf("dlopen(\"%s\", %d);\n", pathname,
		       RTLD_LAZY);
	handle = dlopen(pathname, RTLD_LAZY);
#endif /* RTLD_NOW */
	if (handle == NULL) {
		PyErr_SetString(PyExc_ImportError, dlerror());
		return NULL;
	}
	if (fp != NULL && nhandles < 128)
		handles[nhandles++].handle = handle;
	p = (dl_funcptr) dlsym(handle, funcname);
	return p;
}