lib/ss/get_readline.c

   1 /*
   2  * Copyright 2003 by MIT Student Information Processing Board
   3  *
   4  * Permission to use, copy, modify, and distribute this software and
   5  * its documentation for any purpose is hereby granted, provided that
   6  * the names of M.I.T. and the M.I.T. S.I.P.B. not be used in
   7  * advertising or publicity pertaining to distribution of the software
   8  * without specific, written prior permission.  M.I.T. and the
   9  * M.I.T. S.I.P.B. make no representations about the suitability of
  10  * this software for any purpose.  It is provided "as is" without
  11  * express or implied warranty.
  12  */
  13
  14 #include "config.h"
  15 #ifdef HAS_STDLIB_H
  16 #include <stdlib.h>
  17 #endif
  18 #include "ss_internal.h"
  19 #define size    sizeof(ss_data *)
  20 #ifdef HAVE_DLOPEN
  21 #include <dlfcn.h>
  22 #endif
  23
  24 static void ss_release_readline(ss_data *info)
  25 {
  26 #ifdef HAVE_DLOPEN
  27         if (!info->readline_handle)
  28                 return;
  29
  30         info->readline = 0;
  31         info->add_history = 0;
  32         info->redisplay = 0;
  33         info->rl_completion_matches = 0;
  34         dlclose(info->readline_handle);
  35         info->readline_handle = 0;
  36 #endif
  37 }
  38
  39 /* Libraries we will try to use for readline/editline functionality */
  40 #define DEFAULT_LIBPATH "libreadline.so.6:libreadline.so.5:libreadline.so.4:libreadline.so:libedit.so.2:libedit.so:libeditline.so.0:libeditline.so"
  41
  42 void ss_get_readline(int sci_idx)
  43 {
  44 #ifdef HAVE_DLOPEN
  45         void    *handle = NULL;
  46         ss_data *info = ss_info(sci_idx);
  47         const char **t, *libpath = 0;
  48         char    *tmp, *cp, *next;
  49         char **(**completion_func)(const char *, int, int);
  50
  51         if (info->readline_handle)
  52                 return;
  53
  54         libpath = ss_safe_getenv("SS_READLINE_PATH");
  55         if (!libpath)
  56                 libpath = DEFAULT_LIBPATH;
  57         if (*libpath == 0 || !strcmp(libpath, "none"))
  58                 return;
  59
  60         tmp = malloc(strlen(libpath)+1);
  61         if (!tmp)
  62                 return;
  63         strcpy(tmp, libpath);
  64         for (cp = tmp; cp; cp = next) {
  65                 next = strchr(cp, ':');
  66                 if (next)
  67                         *next++ = 0;
  68                 if (*cp == 0)
  69                         continue;
  70                 if ((handle = dlopen(cp, RTLD_NOW))) {
  71                         /* printf("Using %s for readline library\n", cp); */
  72                         break;
  73                 }
  74         }
  75         free(tmp);
  76         if (!handle)
  77                 return;
  78
  79         info->readline_handle = handle;
  80         info->readline = (char *(*)(const char *))
  81                 dlsym(handle, "readline");
  82         info->add_history = (void (*)(const char *))
  83                 dlsym(handle, "add_history");
  84         info->redisplay = (void (*)(void))
  85                 dlsym(handle, "rl_forced_update_display");
  86         info->rl_completion_matches = (char **(*)(const char *,
  87                                     char *(*)(const char *, int)))
  88                 dlsym(handle, "rl_completion_matches");
  89         if ((t = dlsym(handle, "rl_readline_name")) != NULL)
  90                 *t = info->subsystem_name;
  91         if ((completion_func =
  92              dlsym(handle, "rl_attempted_completion_function")) != NULL)
  93                 *completion_func = ss_rl_completion;
  94         info->readline_shutdown = ss_release_readline;
  95 #endif
  96 }
  97
  98