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