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 2009 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #include <unistd.h>
28 #include <stdio.h>
29 #include <stdarg.h>
30 #include "msg.h"
31 #include "_libld.h"
32
33 /*
34 * GNU ld --wrap support, also known as -z wrap.
35 *
36 * We maintain an AVL tree of wrapped symbol names. Every undefined
37 * symbol is tested against this tree, and those that match have
38 * their names modified to produce the wrapping effect:
39 *
40 * - An undefined reference to XXX is converted to __wrap_XXX
41 * - An undefined reference to __real_XXX is converted to XXX
42 *
43 * This operation has a cost, but that is mitigated by two factors:
44 *
45 * - This is a test feature, not used for production code, so somewhat
46 * longer link times are tolerable.
47 * - The cost of this feature is only paid when it is used. Otherwise,
48 * the sole overhead is the cost of testing the NULL AVL tree pointer
49 * during symbol processing.
50 */
51
52
53 /*
54 * AVL comparison function for WrapSymNode items.
55 *
56 * entry:
57 * n1, n2 - pointers to nodes to be compared
58 *
59 * exit:
60 * Returns -1 if (n1 < n2), 0 if they are equal, and 1 if (n1 > n2)
61 */
62 static int
wrap_cmp(const void * n1,const void * n2)63 wrap_cmp(const void *n1, const void *n2)
64 {
65 int rc;
66
67 rc = strcmp(((WrapSymNode *)n1)->wsn_name,
68 ((WrapSymNode *)n2)->wsn_name);
69
70 if (rc > 0)
71 return (1);
72 if (rc < 0)
73 return (-1);
74 return (0);
75 }
76
77 /*
78 * Enter a -z wrap symbol into the ofl_wrap AVL tree
79 *
80 * entry:
81 * ofl - Output file descriptor
82 * name - Name of symbol to be entered. Caller must ensure that
83 * memory used to hold name remains available for the life
84 * of the link-edit process.
85 *
86 * exit:
87 * On success, updates ofl->wrap_cache with a pointer to the
88 * resulting WrapSymNode, and returns that pointer. On failure,
89 * returns NULL.
90 */
91 WrapSymNode *
ld_wrap_enter(Ofl_desc * ofl,const char * name)92 ld_wrap_enter(Ofl_desc *ofl, const char *name)
93 {
94 WrapSymNode *wsnp, wsn;
95 avl_index_t where;
96 size_t name_len, wrapname_len;
97 char *tmpname;
98
99 /* If this is the first wrap symbol, create the AVL tree */
100 if (ofl->ofl_wrap == NULL) {
101 ofl->ofl_wrap = libld_calloc(1, sizeof (*ofl->ofl_wrap));
102 if (ofl->ofl_wrap == NULL)
103 return (NULL);
104 avl_create(ofl->ofl_wrap, wrap_cmp, sizeof (WrapSymNode),
105 SGSOFFSETOF(WrapSymNode, wsn_avlnode));
106 }
107
108 /* Have we already entered this one? */
109 wsn.wsn_name = name;
110 if ((wsnp = avl_find(ofl->ofl_wrap, &wsn, &where)) != NULL)
111 return (wsnp);
112
113 /*
114 * Allocate a new node, along with room for the wrapped name.
115 * Since strings have byte alignment, we can allocate it immediately
116 * following the AVL node without the need for alignment padding.
117 */
118 name_len = strlen(wsn.wsn_name);
119 wrapname_len = MSG_STR_UU_WRAP_U_SIZE + name_len + 1;
120 if ((wsnp = libld_calloc(1, sizeof (*wsnp) + wrapname_len)) == NULL)
121 return (NULL);
122 wsnp->wsn_name = name;
123
124 wsnp->wsn_wrapname = tmpname = (char *)(wsnp + 1);
125 (void) snprintf(tmpname, wrapname_len, MSG_ORIG(MSG_FMT_STRCAT),
126 MSG_ORIG(MSG_STR_UU_WRAP_U), name);
127
128 /* Insert the new node */
129 avl_insert(ofl->ofl_wrap, wsnp, where);
130 return (wsnp);
131 }
132