xref: /titanic_50/usr/src/cmd/sgs/rtld/common/object.c (revision 275c9da86e89f8abf71135cf63d9fc23671b2e60)
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 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 /*
29  * Object file dependent suport for ELF objects.
30  */
31 #include	"_synonyms.h"
32 
33 #include	<sys/mman.h>
34 #include	<stdio.h>
35 #include	<unistd.h>
36 #include	<libelf.h>
37 #include	<string.h>
38 #include	<dlfcn.h>
39 #include	<debug.h>
40 #include	<libld.h>
41 #include	"_rtld.h"
42 #include	"_audit.h"
43 #include	"_elf.h"
44 
45 static Rt_map	*olmp = 0;
46 
47 static Ehdr	dehdr = { { ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3,
48 			    M_CLASS, M_DATA }, 0, M_MACH, EV_CURRENT };
49 
50 /*
51  * Process a relocatable object.  The static object link map pointer is used as
52  * a flag to determine whether a concatenation is already in progress (ie. an
53  * LD_PRELOAD may specify a list of objects).  The link map returned simply
54  * specifies an `object' flag which the caller can interpret and thus call
55  * elf_obj_fini() to complete the concatenation.
56  */
57 static Rt_map *
58 elf_obj_init(Lm_list *lml, Aliste lmco, const char *name)
59 {
60 	Ofl_desc *	ofl;
61 
62 	/*
63 	 * Initialize an output file descriptor and the entrance criteria.
64 	 */
65 	if ((ofl = (Ofl_desc *)calloc(sizeof (Ofl_desc), 1)) == 0)
66 		return (0);
67 
68 	ofl->ofl_dehdr = &dehdr;
69 
70 	ofl->ofl_flags = (FLG_OF_DYNAMIC | FLG_OF_SHAROBJ | FLG_OF_STRIP);
71 	ofl->ofl_flags1 = (FLG_OF1_RELDYN | FLG_OF1_TEXTOFF | FLG_OF1_MEMORY);
72 	ofl->ofl_lml = lml;
73 
74 	/*
75 	 * As ent_setup() will effectively lazy load the necessary support
76 	 * libraries, make sure ld.so.1 is initialized for plt relocations.
77 	 */
78 	if (elf_rtld_load() == 0)
79 		return (0);
80 
81 	/*
82 	 * Configure libld.so to process objects of the desired target
83 	 * type (this is the first call to libld.so, which will effectively
84 	 * lazyload it).
85 	 */
86 	if (ld_init_target(lml, M_MACH) != 0)
87 		return (0);
88 
89 	/*
90 	 * Obtain a generic set of entrance criteria
91 	 */
92 	if (ld_ent_setup(ofl, syspagsz) == S_ERROR)
93 		return (0);
94 
95 	/*
96 	 * Generate a link map place holder and use the `rt_priv' element to
97 	 * maintain the output file descriptor.
98 	 */
99 	if ((olmp = (Rt_map *)calloc(sizeof (Rt_map), 1)) == 0)
100 		return (0);
101 
102 	DBG_CALL(Dbg_file_elf(lml, name, 0, 0, 0, 0, lml->lm_lmidstr, lmco));
103 	FLAGS(olmp) |= FLG_RT_OBJECT;
104 	olmp->rt_priv = (void *)ofl;
105 
106 	/*
107 	 * Initialize string tables.
108 	 */
109 	if (ld_init_strings(ofl) == S_ERROR)
110 		return (0);
111 
112 	/*
113 	 * Assign the output file name to be the initial object that got us
114 	 * here.  This name is being used for diagnostic purposes only as we
115 	 * don't actually generate an output file unless debugging is enabled.
116 	 */
117 	ofl->ofl_name = name;
118 	ORIGNAME(olmp) = PATHNAME(olmp) = NAME(olmp) = (char *)name;
119 	LIST(olmp) = lml;
120 
121 	lm_append(lml, lmco, olmp);
122 	return (olmp);
123 }
124 
125 /*
126  * Initial processing of a relocatable object.  If this is the first object
127  * encountered we need to initialize some structures, then simply call the
128  * link-edit functionality to provide the initial processing of the file (ie.
129  * reads in sections and symbols, performs symbol resolution if more that one
130  * object file have been specified, and assigns input sections to output
131  * sections).
132  */
133 Rt_map *
134 elf_obj_file(Lm_list *lml, Aliste lmco, const char *name, int fd)
135 {
136 	Rej_desc	rej;
137 
138 	/*
139 	 * If this is the first relocatable object (LD_PRELOAD could provide a
140 	 * list of objects), initialize an input file descriptor and a link map.
141 	 */
142 	if (!olmp) {
143 		/*
144 		 * Load the link-editor library.
145 		 */
146 		if ((olmp = elf_obj_init(lml, lmco, name)) == 0)
147 			return (0);
148 	}
149 
150 	/*
151 	 * Proceed to process the input file.
152 	 */
153 	DBG_CALL(Dbg_util_nl(lml, DBG_NL_STD));
154 	if (ld_process_open(name, name, &fd, (Ofl_desc *)olmp->rt_priv,
155 	    NULL, &rej) == (Ifl_desc *)S_ERROR)
156 		return (0);
157 	return (olmp);
158 }
159 
160 /*
161  * Finish relocatable object processing.  Having already initially processed one
162  * or more objects, complete the generation of a shared object image by calling
163  * the appropriate link-edit functionality (refer to sgs/ld/common/main.c).
164  */
165 Rt_map *
166 elf_obj_fini(Lm_list *lml, Rt_map *lmp)
167 {
168 	Ofl_desc	*ofl = (Ofl_desc *)lmp->rt_priv;
169 	Rt_map		*nlmp;
170 	Addr		etext;
171 	Ehdr		*ehdr;
172 	Phdr		*phdr;
173 	Mmap		*mmaps;
174 	uint_t		phnum, mmapcnt;
175 	Lm_cntl 	*lmc;
176 
177 	DBG_CALL(Dbg_util_nl(lml, DBG_NL_STD));
178 
179 	if (ld_reloc_init(ofl) == S_ERROR)
180 		return (0);
181 	if (ld_sym_validate(ofl) == S_ERROR)
182 		return (0);
183 	if (ld_make_sections(ofl) == S_ERROR)
184 		return (0);
185 	if (ld_create_outfile(ofl) == S_ERROR)
186 		return (0);
187 	if ((etext = ld_update_outfile(ofl)) == (Addr)S_ERROR)
188 		return (0);
189 	if (ld_reloc_process(ofl) == S_ERROR)
190 		return (0);
191 
192 	/*
193 	 * At this point we have a memory image of the shared object.  The link
194 	 * editor would normally simply write this to the required output file.
195 	 * If we're debugging generate a standard temporary output file.
196 	 */
197 	DBG_CALL(Dbg_file_output(ofl));
198 
199 	/*
200 	 * Allocate a mapping array to retain mapped segment information.
201 	 */
202 	ehdr = ofl->ofl_nehdr;
203 	phdr = ofl->ofl_phdr;
204 	if ((mmaps = calloc(ehdr->e_phnum, sizeof (Mmap))) == 0)
205 		return (0);
206 	for (mmapcnt = 0, phnum = 0; phnum < ehdr->e_phnum; phnum++) {
207 		if (phdr[phnum].p_type != PT_LOAD)
208 			continue;
209 
210 		mmaps[mmapcnt].m_vaddr = (caddr_t)
211 		    (phdr[phnum].p_vaddr + (ulong_t)ehdr);
212 		mmaps[mmapcnt].m_msize = phdr[phnum].p_memsz;
213 		mmaps[mmapcnt].m_fsize = phdr[phnum].p_filesz;
214 		mmaps[mmapcnt].m_perm = (PROT_READ | PROT_WRITE | PROT_EXEC);
215 		mmapcnt++;
216 	}
217 
218 	/*
219 	 * Generate a new link map representing the memory image created.
220 	 */
221 	if ((nlmp = elf_new_lm(lml, ofl->ofl_name, ofl->ofl_name,
222 	    ofl->ofl_osdynamic->os_outdata->d_buf, (ulong_t)ehdr,
223 	    (ulong_t)ehdr + etext, CNTL(olmp), (ulong_t)ofl->ofl_size,
224 	    0, 0, 0, mmaps, mmapcnt)) == 0)
225 		return (0);
226 
227 	/*
228 	 * Remove this link map from the end of the link map list and copy its
229 	 * contents into the link map originally created for this file (we copy
230 	 * the contents rather than manipulate the link map pointers as parts
231 	 * of the dlopen code have remembered the original link map address).
232 	 */
233 	NEXT((Rt_map *)PREV(nlmp)) = 0;
234 	/* LINTED */
235 	lmc = (Lm_cntl *)alist_item_by_offset(lml->lm_lists, CNTL(nlmp));
236 	lmc->lc_tail = (Rt_map *)PREV(nlmp);
237 	if (CNTL(nlmp) == ALIST_OFF_DATA)
238 		lml->lm_tail = (Rt_map *)PREV(nlmp);
239 	lml->lm_obj--;
240 
241 	PREV(nlmp) = PREV(olmp);
242 	NEXT(nlmp) = NEXT(olmp);
243 	HANDLES(nlmp) = HANDLES(olmp);
244 	GROUPS(nlmp) = GROUPS(olmp);
245 	STDEV(nlmp) = STDEV(olmp);
246 	STINO(nlmp) = STINO(olmp);
247 
248 	FLAGS(nlmp) |= ((FLAGS(olmp) & ~FLG_RT_OBJECT) | FLG_RT_IMGALLOC);
249 	FLAGS1(nlmp) |= FLAGS1(olmp);
250 	MODE(nlmp) |= MODE(olmp);
251 
252 	NAME(nlmp) = NAME(olmp);
253 	PATHNAME(nlmp) = PATHNAME(olmp);
254 	ORIGNAME(nlmp) = ORIGNAME(olmp);
255 	DIRSZ(nlmp) = DIRSZ(olmp);
256 
257 	ld_ofl_cleanup(ofl);
258 	free(olmp->rt_priv);
259 	(void) memcpy(olmp, nlmp, sizeof (Rt_map));
260 	free(nlmp);
261 	nlmp = olmp;
262 	olmp = 0;
263 
264 	/*
265 	 * Now that we've allocated our permanent Rt_map structure, expand the
266 	 * PATHNAME() and insert it into the FullpathNode AVL tree
267 	 */
268 	if (FLAGS1(nlmp) & FL1_RT_RELATIVE)
269 		(void) fullpath(nlmp, 0);
270 	if (fpavl_insert(lml, nlmp, PATHNAME(nlmp), 0) == 0)
271 		return (0);
272 
273 	/*
274 	 * If we're being audited tell the audit library of the file we've just
275 	 * opened.
276 	 */
277 	if ((lml->lm_tflags | FLAGS1(nlmp)) & LML_TFLG_AUD_MASK) {
278 		if (audit_objopen(lmp, lmp) == 0)
279 			return (0);
280 	}
281 	return (nlmp);
282 }
283