xref: /third_party/python/Python/dynload_shlib.c (revision 7db96d56)
1
2/* Support for dynamic loading of extension modules */
3
4#include "Python.h"
5#include "pycore_interp.h"    // _PyInterpreterState.dlopenflags
6#include "pycore_pystate.h"   // _PyInterpreterState_GET()
7#include "importdl.h"
8
9#include <sys/types.h>
10#include <sys/stat.h>
11
12#if defined(__NetBSD__)
13#include <sys/param.h>
14#if (NetBSD < 199712)
15#include <nlist.h>
16#include <link.h>
17#define dlerror() "error in dynamic linking"
18#endif
19#endif /* NetBSD */
20
21#ifdef HAVE_DLFCN_H
22#include <dlfcn.h>
23#endif
24
25#if (defined(__OpenBSD__) || defined(__NetBSD__)) && !defined(__ELF__)
26#define LEAD_UNDERSCORE "_"
27#else
28#define LEAD_UNDERSCORE ""
29#endif
30
31/* The .so extension module ABI tag, supplied by the Makefile via
32   Makefile.pre.in and configure.  This is used to discriminate between
33   incompatible .so files so that extensions for different Python builds can
34   live in the same directory.  E.g. foomodule.cpython-32.so
35*/
36
37const char *_PyImport_DynLoadFiletab[] = {
38#ifdef __CYGWIN__
39    ".dll",
40#else  /* !__CYGWIN__ */
41    "." SOABI ".so",
42#ifdef ALT_SOABI
43    "." ALT_SOABI ".so",
44#endif
45    ".abi" PYTHON_ABI_STRING ".so",
46    ".so",
47#endif  /* __CYGWIN__ */
48    NULL,
49};
50
51
52dl_funcptr
53_PyImport_FindSharedFuncptr(const char *prefix,
54                            const char *shortname,
55                            const char *pathname, FILE *fp)
56{
57    dl_funcptr p;
58    void *handle;
59    char funcname[258];
60    char pathbuf[260];
61    int dlopenflags=0;
62
63    if (strchr(pathname, '/') == NULL) {
64        /* Prefix bare filename with "./" */
65        PyOS_snprintf(pathbuf, sizeof(pathbuf), "./%-.255s", pathname);
66        pathname = pathbuf;
67    }
68
69    PyOS_snprintf(funcname, sizeof(funcname),
70                  LEAD_UNDERSCORE "%.20s_%.200s", prefix, shortname);
71
72    if (fp != NULL) {
73        struct _Py_stat_struct status;
74        if (_Py_fstat(fileno(fp), &status) == -1)
75            return NULL;
76    }
77
78    dlopenflags = _PyInterpreterState_GET()->dlopenflags;
79
80    handle = dlopen(pathname, dlopenflags);
81
82    if (handle == NULL) {
83        PyObject *mod_name;
84        PyObject *path;
85        PyObject *error_ob;
86        const char *error = dlerror();
87        if (error == NULL)
88            error = "unknown dlopen() error";
89        error_ob = PyUnicode_DecodeLocale(error, "surrogateescape");
90        if (error_ob == NULL)
91            return NULL;
92        mod_name = PyUnicode_FromString(shortname);
93        if (mod_name == NULL) {
94            Py_DECREF(error_ob);
95            return NULL;
96        }
97        path = PyUnicode_DecodeFSDefault(pathname);
98        if (path == NULL) {
99            Py_DECREF(error_ob);
100            Py_DECREF(mod_name);
101            return NULL;
102        }
103        PyErr_SetImportError(error_ob, mod_name, path);
104        Py_DECREF(error_ob);
105        Py_DECREF(mod_name);
106        Py_DECREF(path);
107        return NULL;
108    }
109    p = (dl_funcptr) dlsym(handle, funcname);
110    return p;
111}
112