Python/dynload_shlib.c

   1 /***********************************************************
   2 Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
   3 The Netherlands.
   4
   5                         All Rights Reserved
   6
   7 Permission to use, copy, modify, and distribute this software and its
   8 documentation for any purpose and without fee is hereby granted,
   9 provided that the above copyright notice appear in all copies and that
  10 both that copyright notice and this permission notice appear in
  11 supporting documentation, and that the names of Stichting Mathematisch
  12 Centrum or CWI or Corporation for National Research Initiatives or
  13 CNRI not be used in advertising or publicity pertaining to
  14 distribution of the software without specific, written prior
  15 permission.
  16
  17 While CWI is the initial source for this software, a modified version
  18 is made available by the Corporation for National Research Initiatives
  19 (CNRI) at the Internet address ftp://ftp.python.org.
  20
  21 STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
  22 REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
  23 MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
  24 CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
  25 DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  26 PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  27 TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  28 PERFORMANCE OF THIS SOFTWARE.
  29
  30 ******************************************************************/
  31
  32 /* Support for dynamic loading of extension modules */
  33
  34 #include "Python.h"
  35 #include "importdl.h"
  36
  37 #include <sys/types.h>
  38 #include <sys/stat.h>
  39 #if defined(__NetBSD__) && (NetBSD < 199712)
  40 #include <nlist.h>
  41 #include <link.h>
  42 #define dlerror() "error in dynamic linking"
  43 #else
  44 #ifdef HAVE_DLFCN_H
  45 #include <dlfcn.h>
  46 #endif
  47 #endif
  48
  49 #ifndef RTLD_LAZY
  50 #define RTLD_LAZY 1
  51 #endif
  52
  53
  54 const struct filedescr _PyImport_DynLoadFiletab[] = {
  55         {".so", "rb", C_EXTENSION},
  56         {"module.so", "rb", C_EXTENSION},
  57         {0, 0}
  58 };
  59
  60 static struct {
  61         dev_t dev;
  62         ino_t ino;
  63         void *handle;
  64 } handles[128];
  65 static int nhandles = 0;
  66
  67
  68 dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,
  69                                     const char *pathname, FILE *fp)
  70 {
  71         dl_funcptr p;
  72         void *handle;
  73         char funcname[258];
  74         char pathbuf[260];
  75
  76         if (strchr(pathname, '/') == NULL) {
  77                 /* Prefix bare filename with "./" */
  78                 sprintf(pathbuf, "./%-.255s", pathname);
  79                 pathname = pathbuf;
  80         }
  81
  82         /* ### should there be a leading underscore for some platforms? */
  83         sprintf(funcname, "init%.200s", shortname);
  84
  85         if (fp != NULL) {
  86                 int i;
  87                 struct stat statb;
  88                 fstat(fileno(fp), &statb);
  89                 for (i = 0; i < nhandles; i++) {
  90                         if (statb.st_dev == handles[i].dev &&
  91                             statb.st_ino == handles[i].ino) {
  92                                 p = (dl_funcptr) dlsym(handles[i].handle,
  93                                                        funcname);
  94                                 return p;
  95                         }
  96                 }
  97                 if (nhandles < 128) {
  98                         handles[nhandles].dev = statb.st_dev;
  99                         handles[nhandles].ino = statb.st_ino;
 100                 }
 101         }
 102
 103 #ifdef RTLD_NOW
 104         /* RTLD_NOW: resolve externals now
 105            (i.e. core dump now if some are missing) */
 106         handle = dlopen(pathname, RTLD_NOW);
 107 #else
 108         if (Py_VerboseFlag)
 109                 printf("dlopen(\"%s\", %d);\n", pathname,
 110                        RTLD_LAZY);
 111         handle = dlopen(pathname, RTLD_LAZY);
 112 #endif /* RTLD_NOW */
 113         if (handle == NULL) {
 114                 PyErr_SetString(PyExc_ImportError, dlerror());
 115                 return NULL;
 116         }
 117         if (fp != NULL && nhandles < 128)
 118                 handles[nhandles++].handle = handle;
 119         p = (dl_funcptr) dlsym(handle, funcname);
 120         return p;
 121 }