xref: /titanic_51/usr/src/cmd/sgs/libld/common/support.c (revision 381a2a9a387f449fab7d0c7e97c4184c26963abf)
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 2006 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include	<stdio.h>
30 #include	<dlfcn.h>
31 #include	<libelf.h>
32 #include	<link.h>
33 #include	<debug.h>
34 #include	"msg.h"
35 #include	"_libld.h"
36 
37 /*
38  * Table which defines the default functions to be called by the library
39  * SUPPORT (-S <libname>).  These functions can be redefined by the
40  * ld_support_loadso() routine.
41  */
42 static Support_list support[LDS_NUM] = {
43 	{MSG_ORIG(MSG_SUP_VERSION),	{ 0, 0 }},	/* LDS_VERSION */
44 	{MSG_ORIG(MSG_SUP_INPUT_DONE),	{ 0, 0 }},	/* LDS_INPUT_DONE */
45 #if	defined(_ELF64)
46 	{MSG_ORIG(MSG_SUP_START_64),	{ 0, 0 }},	/* LDS_START */
47 	{MSG_ORIG(MSG_SUP_ATEXIT_64),	{ 0, 0 }},	/* LDS_ATEXIT */
48 	{MSG_ORIG(MSG_SUP_FILE_64),	{ 0, 0 }},	/* LDS_FILE */
49 	{MSG_ORIG(MSG_SUP_INSEC_64),	{ 0, 0 }},	/* LDS_INSEC */
50 	{MSG_ORIG(MSG_SUP_SEC_64),	{ 0, 0 }}	/* LDS_SEC */
51 #else	/* Elf32 */
52 	{MSG_ORIG(MSG_SUP_START),	{ 0, 0 }},	/* LDS_START */
53 	{MSG_ORIG(MSG_SUP_ATEXIT),	{ 0, 0 }},	/* LDS_ATEXIT */
54 	{MSG_ORIG(MSG_SUP_FILE),	{ 0, 0 }},	/* LDS_FILE */
55 	{MSG_ORIG(MSG_SUP_INSEC),	{ 0, 0 }},	/* LDS_INSEC */
56 	{MSG_ORIG(MSG_SUP_SEC),		{ 0, 0 }}	/* LDS_SEC */
57 #endif
58 };
59 
60 /*
61  * Loads in a support shared object specified using the SGS_SUPPORT environment
62  * variable or the -S ld option, and determines which interface functions are
63  * provided by that object.
64  */
65 uintptr_t
66 ld_sup_loadso(Ofl_desc *ofl, const char *obj)
67 {
68 	void		*handle, (*fptr)();
69 	Func_list	*flp;
70 	uint_t		interface, version = LD_SUP_VERSION1;
71 
72 	/*
73 	 * Load the required support library.  If we are unable to load it fail
74 	 * with a fatal error.
75 	 */
76 	if ((handle = dlopen(obj, (RTLD_LAZY | RTLD_FIRST))) == NULL) {
77 		eprintf(ofl->ofl_lml, ERR_FATAL, MSG_INTL(MSG_SUP_NOLOAD),
78 		    obj, dlerror());
79 		return (S_ERROR);
80 	}
81 
82 	for (interface = 0; interface < LDS_NUM; interface++) {
83 		if ((fptr = (void (*)())dlsym(handle,
84 		    support[interface].sup_name)) == NULL)
85 			continue;
86 
87 		if ((flp = libld_malloc(sizeof (Func_list))) == NULL)
88 			return (S_ERROR);
89 
90 		flp->fl_obj = obj;
91 		flp->fl_fptr = fptr;
92 		DBG_CALL(Dbg_support_load(ofl->ofl_lml, obj,
93 		    support[interface].sup_name));
94 
95 		if (interface == LDS_VERSION) {
96 			DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
97 			    support[LDS_VERSION].sup_name, LDS_VERSION, 0));
98 
99 			version = ((uint_t(*)())flp->fl_fptr)(LD_SUP_VCURRENT);
100 			if ((version == LD_SUP_VNONE) ||
101 			    (version > LD_SUP_VCURRENT)) {
102 				eprintf(ofl->ofl_lml, ERR_FATAL,
103 				    MSG_INTL(MSG_SUP_BADVERSION),
104 				    LD_SUP_VCURRENT, version);
105 				(void) dlclose(handle);
106 				return (S_ERROR);
107 			}
108 		}
109 		flp->fl_version = version;
110 		if (list_appendc(&support[interface].sup_funcs, flp) == 0)
111 			return (S_ERROR);
112 	}
113 	return (1);
114 }
115 
116 /*
117  * Wrapper routines for the ld support library calls.
118  */
119 void
120 ld_sup_start(Ofl_desc *ofl, const Half etype, const char *caller)
121 {
122 	Func_list	*flp;
123 	Listnode	*lnp;
124 
125 	for (LIST_TRAVERSE(&support[LDS_START].sup_funcs, lnp, flp)) {
126 		DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
127 		    support[LDS_START].sup_name, LDS_START, ofl->ofl_name));
128 		(*flp->fl_fptr)(ofl->ofl_name, etype, caller);
129 	}
130 }
131 
132 void
133 ld_sup_atexit(Ofl_desc *ofl, int ecode)
134 {
135 	Func_list	*flp;
136 	Listnode	*lnp;
137 
138 	for (LIST_TRAVERSE(&support[LDS_ATEXIT].sup_funcs, lnp, flp)) {
139 		DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
140 		    support[LDS_ATEXIT].sup_name, LDS_ATEXIT, 0));
141 		(*flp->fl_fptr)(ecode);
142 	}
143 }
144 
145 void
146 ld_sup_file(Ofl_desc *ofl, const char *ifile, const Elf_Kind ekind, int flags,
147     Elf *elf)
148 {
149 	Func_list	*flp;
150 	Listnode	*lnp;
151 
152 	for (LIST_TRAVERSE(&support[LDS_FILE].sup_funcs, lnp, flp)) {
153 		int	_flags = 0;
154 
155 		if (!(flags & FLG_IF_CMDLINE))
156 			_flags |= LD_SUP_DERIVED;
157 		if (!(flags & FLG_IF_NEEDED))
158 			_flags |= LD_SUP_INHERITED;
159 		if (flags & FLG_IF_EXTRACT)
160 			_flags |= LD_SUP_EXTRACTED;
161 
162 		DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
163 		    support[LDS_FILE].sup_name, LDS_FILE, ifile));
164 		(*flp->fl_fptr)(ifile, ekind, _flags, elf);
165 	}
166 }
167 
168 uintptr_t
169 ld_sup_input_section(Ofl_desc *ofl, Ifl_desc *ifl, const char *sname,
170     Shdr **oshdr, Word ndx, Elf_Scn *scn, Elf *elf)
171 {
172 	Func_list	*flp;
173 	Listnode	*lnp;
174 	uint_t		flags = 0;
175 	Elf_Data	*data = NULL;
176 	Shdr		*nshdr = *oshdr;
177 
178 	for (LIST_TRAVERSE(&support[LDS_INSEC].sup_funcs, lnp, flp)) {
179 		/*
180 		 * This interface was introduced in VERSION2.  Only call this
181 		 * function for libraries reporting support for version 2 or
182 		 * above.
183 		 */
184 		if (flp->fl_version < LD_SUP_VERSION2)
185 			continue;
186 
187 		if ((data == NULL) &&
188 		    ((data = elf_getdata(scn, NULL)) == NULL)) {
189 			eprintf(ofl->ofl_lml, ERR_ELF,
190 			    MSG_INTL(MSG_ELF_GETDATA), ifl->ifl_name);
191 			ofl->ofl_flags |= FLG_OF_FATAL;
192 			return (S_ERROR);
193 		}
194 
195 		DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
196 		    support[LDS_INSEC].sup_name, LDS_INSEC, sname));
197 		(*flp->fl_fptr)(sname, &nshdr, ndx, data, elf, &flags);
198 	}
199 
200 	/*
201 	 * If the section header has been re-allocated (known to occur with
202 	 * libCCexcept.so), then diagnose the section header difference and
203 	 * return the new section header.
204 	 */
205 	if (nshdr != *oshdr) {
206 		Dbg_shdr_modified(ofl->ofl_lml, ifl->ifl_ehdr->e_machine,
207 		    *oshdr, nshdr, sname);
208 		*oshdr = nshdr;
209 	}
210 	return (0);
211 }
212 
213 void
214 ld_sup_section(Ofl_desc *ofl, const char *scn, Shdr *shdr, Word ndx,
215     Elf_Data *data, Elf *elf)
216 {
217 	Func_list	*flp;
218 	Listnode	*lnp;
219 
220 	for (LIST_TRAVERSE(&support[LDS_SEC].sup_funcs, lnp, flp)) {
221 		DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
222 		    support[LDS_SEC].sup_name, LDS_SEC, scn));
223 		(*flp->fl_fptr)(scn, shdr, ndx, data, elf);
224 	}
225 }
226 
227 void
228 ld_sup_input_done(Ofl_desc *ofl)
229 {
230 	Func_list	*flp;
231 	Listnode	*lnp;
232 	uint_t		flags = 0;
233 
234 	for (LIST_TRAVERSE(&support[LDS_INPUT_DONE].sup_funcs, lnp, flp)) {
235 		/*
236 		 * This interface was introduced in VERSION2.  Only call this
237 		 * function for libraries reporting support for version 2 or
238 		 * above.
239 		 */
240 		if (flp->fl_version < LD_SUP_VERSION2)
241 			continue;
242 
243 		DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
244 		    support[LDS_INPUT_DONE].sup_name, LDS_INPUT_DONE, 0));
245 		(*flp->fl_fptr)(&flags);
246 	}
247 }
248