get_readline.c revision efc6f628e15de95bcd13e4f0ee223cb42115d520 
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#ifdef HAS_STDLIB_H
15#include <stdlib.h>
16#endif
17#include "ss_internal.h"
18#define	size	sizeof(ss_data *)
19#ifdef HAVE_DLOPEN
20#include <dlfcn.h>
21#endif
22
23static void ss_release_readline(ss_data *info)
24{
25#ifdef HAVE_DLOPEN
26	if (!info->readline_handle)
27		return;
28
29	info->readline = 0;
30	info->add_history = 0;
31	info->redisplay = 0;
32	info->rl_completion_matches = 0;
33	dlclose(info->readline_handle);
34	info->readline_handle = 0;
35#endif
36}
37
38/* Libraries we will try to use for readline/editline functionality */
39#define DEFAULT_LIBPATH "libreadline.so.5:libreadline.so.4:libreadline.so:libedit.so.2:libedit.so:libeditline.so.0:libeditline.so"
40
41void ss_get_readline(int sci_idx)
42{
43#ifdef HAVE_DLOPEN
44	void	*handle = NULL;
45	ss_data *info = ss_info(sci_idx);
46	const char **t, *libpath = 0;
47	char	*tmp, *cp, *next;
48	char **(**completion_func)(const char *, int, int);
49
50	if (info->readline_handle)
51		return;
52
53	libpath = ss_safe_getenv("SS_READLINE_PATH");
54	if (!libpath)
55		libpath = DEFAULT_LIBPATH;
56	if (*libpath == 0 || !strcmp(libpath, "none"))
57		return;
58
59	tmp = malloc(strlen(libpath)+1);
60	if (!tmp)
61		return;
62	strcpy(tmp, libpath);
63	for (cp = tmp; cp; cp = next) {
64		next = strchr(cp, ':');
65		if (next)
66			*next++ = 0;
67		if (*cp == 0)
68			continue;
69		if ((handle = dlopen(cp, RTLD_NOW))) {
70			/* printf("Using %s for readline library\n", cp); */
71			break;
72		}
73	}
74	free(tmp);
75	if (!handle)
76		return;
77
78	info->readline_handle = handle;
79	info->readline = (char *(*)(const char *))
80		dlsym(handle, "readline");
81	info->add_history = (void (*)(const char *))
82		dlsym(handle, "add_history");
83	info->redisplay = (void (*)(void))
84		dlsym(handle, "rl_forced_update_display");
85	info->rl_completion_matches = (char **(*)(const char *,
86				    char *(*)(const char *, int)))
87		dlsym(handle, "rl_completion_matches");
88	if ((t = dlsym(handle, "rl_readline_name")) != NULL)
89		*t = info->subsystem_name;
90	if ((completion_func =
91	     dlsym(handle, "rl_attempted_completion_function")) != NULL)
92		*completion_func = ss_rl_completion;
93	info->readline_shutdown = ss_release_readline;
94#endif
95}
96
97
98