Python/dynload_shlib.c

   1
   2 /* Support for dynamic loading of extension modules */
   3
   4 #include "Python.h"
   5 #include "importdl.h"
   6
   7 #include <sys/types.h>
   8 #include <sys/stat.h>
   9
  10 #if defined(__NetBSD__)
  11 #include <sys/param.h>
  12 #if (NetBSD < 199712)
  13 #include <nlist.h>
  14 #include <link.h>
  15 #define dlerror() "error in dynamic linking"
  16 #endif
  17 #endif /* NetBSD */
  18
  19 #ifdef HAVE_DLFCN_H
  20 #include <dlfcn.h>
  21 #endif
  22
  23 #if (defined(__OpenBSD__) || defined(__NetBSD__)) && !defined(__ELF__)
  24 #define LEAD_UNDERSCORE "_"
  25 #else
  26 #define LEAD_UNDERSCORE ""
  27 #endif
  28
  29 #ifndef RTLD_LAZY
  30 #define RTLD_LAZY 1
  31 #endif
  32
  33
  34 const struct filedescr _PyImport_DynLoadFiletab[] = {
  35 #ifdef __CYGWIN__
  36         {".dll", "rb", C_EXTENSION},
  37         {"module.dll", "rb", C_EXTENSION},
  38 #else
  39         {".so", "rb", C_EXTENSION},
  40         {"module.so", "rb", C_EXTENSION},
  41 #endif
  42         {0, 0}
  43 };
  44
  45 static struct {
  46         dev_t dev;
  47         ino_t ino;
  48         void *handle;
  49 } handles[128];
  50 static int nhandles = 0;
  51
  52
  53 dl_funcptr _PyImport_GetDynLoadFunc(const char *fqname, const char *shortname,
  54                                     const char *pathname, FILE *fp)
  55 {
  56         dl_funcptr p;
  57         void *handle;
  58         char funcname[258];
  59         char pathbuf[260];
  60
  61         if (strchr(pathname, '/') == NULL) {
  62                 /* Prefix bare filename with "./" */
  63                 sprintf(pathbuf, "./%-.255s", pathname);
  64                 pathname = pathbuf;
  65         }
  66
  67         sprintf(funcname, LEAD_UNDERSCORE "init%.200s", shortname);
  68
  69         if (fp != NULL) {
  70                 int i;
  71                 struct stat statb;
  72                 fstat(fileno(fp), &statb);
  73                 for (i = 0; i < nhandles; i++) {
  74                         if (statb.st_dev == handles[i].dev &&
  75                             statb.st_ino == handles[i].ino) {
  76                                 p = (dl_funcptr) dlsym(handles[i].handle,
  77                                                        funcname);
  78                                 return p;
  79                         }
  80                 }
  81                 if (nhandles < 128) {
  82                         handles[nhandles].dev = statb.st_dev;
  83                         handles[nhandles].ino = statb.st_ino;
  84                 }
  85         }
  86
  87 #ifdef RTLD_NOW
  88         /* RTLD_NOW: resolve externals now
  89            (i.e. core dump now if some are missing) */
  90         handle = dlopen(pathname, RTLD_NOW);
  91 #else
  92         if (Py_VerboseFlag)
  93                 printf("dlopen(\"%s\", %d);\n", pathname,
  94                        RTLD_LAZY);
  95         handle = dlopen(pathname, RTLD_LAZY);
  96 #endif /* RTLD_NOW */
  97         if (handle == NULL) {
  98                 PyErr_SetString(PyExc_ImportError, dlerror());
  99                 return NULL;
 100         }
 101         if (fp != NULL && nhandles < 128)
 102                 handles[nhandles++].handle = handle;
 103         p = (dl_funcptr) dlsym(handle, funcname);
 104         return p;
 105 }