xref: /illumos-gate/usr/src/cmd/sgs/libconv/common/demangle.c (revision dcdeca0a948b9d3139743db085d193c9db8ff2a3)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright 2018, Joyent, Inc.
25  */
26 
27 #include	<stdio.h>
28 #include	<demangle-sys.h>
29 #include	"_conv.h"
30 #include	"demangle_msg.h"
31 
32 /*
33  * Demangle C++ symbols.
34  *
35  * This routine acts as a generic routine for use by liblddbg (and hence tools
36  * like elfdump(1) and pvs(1)), ld(1) and ld.so.1(1).
37  *
38  * The C++ ABI-2 places no limits on symbol names, thus when demangling a name
39  * it's possible the buffer won't be big enough (DEMANGLE_ESPACE) so here we
40  * try to allocate bigger buffers.  However, we place a limit on this buffer
41  * size for fear of a C++ error sending us into an infinit loop.
42  *
43  * NOTE. we create and use a common buffer for use by cplus_demangle(), thus
44  * each call to this routine will override the contents of any existing call.
45  * Normally this is sufficient for typical error diagnostics referencing one
46  * symbol.  For those diagnostics using more than one symbol name, all but the
47  * last name must be copied to a temporary buffer (regardless of whether
48  * demangling occurred, as the process of attempting to demangle may damage the
49  * buffer).  One model is:
50  *
51  *	if ((_name1 = demangle(name1)) != name1) {
52  *		char *	__name1 = strdupa(_name1);
53  *		name1 = (const char *)__name1;
54  *	}
55  *	name2 = demangle(name2);
56  *	eprintf(format, name1, name2);
57  */
58 #define	SYM_MAX	1000
59 
60 const char *
61 conv_demangle_name(const char *name)
62 {
63 	static char	*(*fptr)() = 0;
64 	static volatile int loading = 0;
65 	char *d;
66 
67 	if (loading)
68 		return (name);
69 
70 	/*
71 	 * If we haven't located the demangler yet try now (we do this rather
72 	 * than maintain a static dependency on libdemangle as it's part of an
73 	 * optional package).  Null the str element out to reject any other
74 	 * callers until this operation is complete - under ld.so.1 we can get
75 	 * into serious recursion without this.
76 	 */
77 	if (fptr == 0) {
78 		void	*hdl;
79 
80 		loading = 1;
81 		if (!(hdl = dlopen(MSG_ORIG(MSG_DEM_LIB), RTLD_LAZY)) ||
82 		    !(fptr = (char *(*)())dlsym(hdl, MSG_ORIG(MSG_DEM_SYM))))
83 			return (name);
84 		loading = 0;
85 	}
86 
87 	if ((d = fptr(name, SYSDEM_LANG_AUTO, NULL)) == NULL)
88 		return (name);
89 
90 	return (d);
91 }
92