/*************************************************************************
*									 *
*	 YAP Prolog 							 *
*									 *
*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
*									 *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
*									 *
**************************************************************************
*									 *
* File:		load_dl.c						 *
* comments:	dl based dynamic loaderr of external routines		 *
*               tested on i486-linuxelf					 *
*************************************************************************/

#include "Yap.h"
#include "YapHeap.h"
#include "Yatom.h"
#include "yapio.h"

#include "Foreign.h"

#if LOAD_DL

// use SWI-Prolog code if all else fails
char *findExecutable(const char *av0, char *buffer);

#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if defined(__APPLE__)
#include <dlfcn.h>
#include <mach-o/dyld.h>
#endif

typedef void (*prismf)(void);

/* only works for dlls */
int Yap_CallFunctionByName(const char *thing_string);

int Yap_CallFunctionByName(const char *thing_string) {
  void *handle = dlopen(NULL, RTLD_LAZY
#ifndef __CYGWIN__
#ifdef RTLD_NOLOAD
                                  | RTLD_NOLOAD
#endif
#endif
                        );
  // you could do RTLD_NOW as well.  shouldn't matter
  if (!handle) {
    CACHE_REGS
    Yap_Error(SYSTEM_ERROR_INTERNAL, ARG1,
              "Dynamic linking on main module : %s\n", dlerror());
  }
  prismf *addr = (prismf *)dlsym(handle, thing_string);
  if (addr)
    (*addr)();
  dlclose(handle);
  return TRUE;
}

/*
 *   YAP_FindExecutable(argv[0]) should be called on yap initialization to
 *   locate the executable of Yap
*/
char *Yap_FindExecutable(void) {
#if HAVE_GETEXECNAME
  // Solaris
  return getexecname();
#elif __APPLE__
  char *buf = malloc(YAP_FILENAME_MAX);

  uint32_t size;
  if (!_NSGetExecutablePath(buf, &size)) {
    buf = realloc(buf, size + 1);
    return buf;
  }     return "yap";
#elif defined(__linux__)
  enum { BUFFERSIZE = 1024 };
  char *buf = malloc(BUFFERSIZE);
  ssize_t len = readlink("/proc/self/exe", buf, sizeof(buf) - 1);

  if (len != -1) {
    buf[len] = '\0';
    return buf;
  }
// follow through to standard method
#elif defined(__FreeBSD__) || defined(__DragonFly__)
  enum { BUFFERSIZE = 1024 };
  char *buf = malloc(BUFFERSIZE);
  ssize_t len = readlink("/proc/curproc/file", buf, sizeof(buf) - 1);

  if (len != -1) {
    buf[len] = '\0';
    return buf;
  }
  int mib[4];
  mib[0] = CTL_KERN;
  mib[1] = KERN_PROC;
  mib[2] = KERN_PROC_PATHNAME;
  mib[3] = -1; // current process
  size_t cb = BUFFERSIZE;
  sysctl(mib, 4, buf, &cb, NULL, 0);
// follow through to standard method
#endif
  return NULL;
}

void *Yap_LoadForeignFile(char *file, int flags) {
  CACHE_REGS
  int dlflag;
  void *out;

  if (flags & EAGER_LOADING)
    dlflag = RTLD_NOW;
  else
    dlflag = RTLD_LAZY;
  if (flags & GLOBAL_LOADING)
    dlflag |= RTLD_GLOBAL;
#ifndef __CYGWIN__
  else
    dlflag |= RTLD_LOCAL;
#endif
  if (!Yap_findFile(file, NULL, NULL, LOCAL_FileNameBuf, true, YAP_OBJ, true, true)) {
    /* use LD_LIBRARY_PATH */
    strncpy(LOCAL_FileNameBuf, file, YAP_FILENAME_MAX - 1);
    strncat(LOCAL_FileNameBuf, ".", YAP_FILENAME_MAX - 1);
    strncat(LOCAL_FileNameBuf, "SO_EXT", YAP_FILENAME_MAX - 1);
  }
  out = (void *)dlopen(LOCAL_FileNameBuf, flags);
  if (out == NULL) {
    const char *m_os = dlerror();
    if (m_os) {
      strncpy(LOCAL_ErrorSay, m_os, MAX_ERROR_MSG_SIZE - 1);
    } else {
      LOCAL_ErrorMessage = "dlopen failed";
    }
  }
  return out;
}

int Yap_CallForeignFile(void *handle, char *f) {
  YapInitProc proc = (YapInitProc)dlsym(handle, f);
  if (!proc) {
    /* Yap_Error(SYSTEM_ERROR_INTERNAL, ARG1, "dlsym error %s\n", dlerror());*/
    return FALSE;
  }
  (*proc)();
  return TRUE;
}

int Yap_CloseForeignFile(void *handle) {
  if (dlclose(handle) < 0) {
    CACHE_REGS
    Yap_Error(SYSTEM_ERROR_INTERNAL, ARG1, "dlclose error %s\n", dlerror());
    return -1;
  }
  return 0;
}

/*
 * LoadForeign(ofiles,libs,proc_name,init_proc) dynamically loads foreign
 * code files and libraries and locates an initialization routine
*/
static Int LoadForeign(StringList ofiles, StringList libs, char *proc_name,
                       YapInitProc *init_proc) {
  CACHE_REGS

  while (libs) {
    const char *file = AtomName(libs->name);
    if (!Yap_findFile(file, NULL, NULL, LOCAL_FileNameBuf, true, YAP_OBJ, true, true)) {
      /* use LD_LIBRARY_PATH */
      strncpy(LOCAL_FileNameBuf, (char *)AtomName(libs->name),
              YAP_FILENAME_MAX);
    }

#ifdef __osf__
    if ((libs->handle = dlopen(LOCAL_FileNameBuf, RTLD_LAZY)) == NULL)
#else
    if ((libs->handle = dlopen(LOCAL_FileNameBuf, RTLD_LAZY | RTLD_GLOBAL)) ==
        NULL)
#endif
    {
      strcpy(LOCAL_ErrorSay, dlerror());
      return LOAD_FAILLED;
    }
    libs = libs->next;
  }

  while (ofiles) {
    void *handle;

    /* load libraries first so that their symbols are available to
       other routines */

    /* dlopen wants to follow the LD_CONFIG_PATH */
    const char *file = AtomName(ofiles->name);
    if (!Yap_findFile(file, NULL, NULL, LOCAL_FileNameBuf, true, YAP_OBJ, true, true)) {
      strcpy(LOCAL_ErrorSay,
             "%% Trying to open unexisting file in LoadForeign");
      return LOAD_FAILLED;
    }
#ifdef __osf__
    if ((handle = dlopen(LOCAL_FileNameBuf, RTLD_LAZY)) == 0)
#else
    if ((handle = dlopen(LOCAL_FileNameBuf, RTLD_LAZY | RTLD_GLOBAL)) == 0)
#endif
    {
      fprintf(stderr, "dlopen of image %s failed: %s\n", LOCAL_FileNameBuf,
              dlerror());
      /*      strcpy(LOCAL_ErrorSay,dlerror());*/
      return LOAD_FAILLED;
    }

    ofiles->handle = handle;

    if (proc_name && !*init_proc)
      *init_proc = (YapInitProc)dlsym(handle, proc_name);

    ofiles = ofiles->next;
  }

  if (!*init_proc) {
    strcpy(LOCAL_ErrorSay, "Could not locate initialization routine");
    return LOAD_FAILLED;
  }

  return LOAD_SUCCEEDED;
}

Int Yap_LoadForeign(StringList ofiles, StringList libs, char *proc_name,
                    YapInitProc *init_proc) {
  return LoadForeign(ofiles, libs, proc_name, init_proc);
}

void Yap_ShutdownLoadForeign(void) {
  ForeignObj *f_code;

  f_code = ForeignCodeLoaded;
  while (f_code != NULL) {
    StringList objs, libs, old;
    ForeignObj *of_code = f_code;

    objs = f_code->objs;
    while (objs != NULL) {
      old = objs;
      if (dlclose(objs->handle) != 0)
        return; /* ERROR */
      objs = objs->next;
      Yap_FreeCodeSpace((ADDR)old);
    }
    libs = f_code->libs;
    while (libs != NULL) {
      old = libs;
      if (dlclose(libs->handle) != 0)
        return; /* ERROR */
      libs = libs->next;
      Yap_FreeCodeSpace((ADDR)old);
    }
    f_code = f_code->next;
    Yap_FreeCodeSpace((ADDR)of_code);
  }
  /*
    make sure that we don't try to close foreign code several times, eg,
    from within an error handler
  */
  ForeignCodeLoaded = NULL;
}

Int Yap_ReLoadForeign(StringList ofiles, StringList libs, char *proc_name,
                      YapInitProc *init_proc) {
  return (LoadForeign(ofiles, libs, proc_name, init_proc));
}

#endif

#if SIMICS

void dlopen(void) {}

void dlclose(void) {}

void dlsym(void) {}

#endif