1 /* vi: set sw=4 ts=4: */
2 /* sparc ELF shared library loader suppport
4 * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
5 * David Engel, Hongjiu Lu and Mitch D'Souza
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. The name of the above contributors may not be
15 * used to endorse or promote products derived from this software
16 * without specific prior written permission.
18 * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 /* Program to load an ELF binary on a linux system, and run it.
32 References to symbols in sharable libraries can be resolved by either
33 an ELF sharable library or a linux style of shared library. */
35 /* Disclaimer: I have never seen any AT&T source code for SVr4, nor have
36 I ever taken any courses on internals. This program was developed using
37 information available through the book "UNIX SYSTEM V RELEASE 4,
38 Programmers guide: Ansi C and Programming Support Tools", which did
39 a more than adequate job of explaining everything required to get this
42 /* Some SPARC opcodes we need to use for self-modifying code. */
43 #define OPCODE_NOP 0x01000000 /* nop */
44 #define OPCODE_CALL 0x40000000 /* call ?; add PC-rel word address */
45 #define OPCODE_SETHI_G1 0x03000000 /* sethi ?, %g1; add value>>10 */
46 #define OPCODE_JMP_G1 0x81c06000 /* jmp %g1+?; add lo 10 bits of value */
47 #define OPCODE_SAVE_SP 0x9de3bfa8 /* save %sp, -(16+6)*4, %sp */
48 #define OPCODE_BA 0x30800000 /* b,a ?; add PC-rel word address */
50 extern int _dl_linux_resolve(void);
53 _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
55 ELF_RELOC *this_reloc;
62 ElfW(Addr) instr_addr;
65 rel_addr = (char *)tpnt->dynamic_info[DT_JMPREL];
67 * Generate the correct relocation index into the .rela.plt section.
69 reloc_entry = (reloc_entry >> 10) - 0xc;
71 this_reloc = (ELF_RELOC *)(rel_addr + reloc_entry);
72 symtab_index = ELF_R_SYM(this_reloc->r_info);
74 symtab = (ElfW(Sym) *)tpnt->dynamic_info[DT_SYMTAB];
75 strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
76 symname = strtab + symtab[symtab_index].st_name;
78 /* Address of the jump instruction to fix up. */
79 instr_addr = (this_reloc->r_offset + tpnt->loadaddr);
80 got_addr = (char **)instr_addr;
82 /* Get the address of the GOT entry */
83 new_addr = _dl_find_hash(symname, tpnt->symbol_scope, tpnt, ELF_RTYPE_CLASS_PLT, NULL);
84 if (unlikely(!new_addr)) {
85 _dl_dprintf(2, "%s: Can't resolve symbol '%s'\n", _dl_progname, symname);
89 #if defined (__SUPPORT_LD_DEBUG__)
90 if ((unsigned long)got_addr < 0x40000000) {
91 if (_dl_debug_bindings) {
92 _dl_dprintf(_dl_debug_file, "\nresolve function: %s", symname);
94 _dl_dprintf(_dl_debug_file,
95 "\tpatched: %x ==> %x @ %x\n",
96 *got_addr, new_addr, got_addr);
99 if (!_dl_debug_nofixups)
102 got_addr[1] = (char *) (OPCODE_SETHI_G1 | (((unsigned int) new_addr >> 10) & 0x3fffff));
103 got_addr[2] = (char *) (OPCODE_JMP_G1 | ((unsigned int) new_addr & 0x3ff));
106 return (unsigned long)new_addr;
110 _dl_parse(struct elf_resolve *tpnt, struct dyn_elf *scope,
111 unsigned long rel_addr, unsigned long rel_size,
112 int (*reloc_fnc)(struct elf_resolve *tpnt, struct dyn_elf *scope,
113 ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab))
121 /* Parse the relocation information. */
122 rpnt = (ELF_RELOC *)rel_addr;
123 rel_size /= sizeof(ELF_RELOC);
125 symtab = (ElfW(Sym) *)tpnt->dynamic_info[DT_SYMTAB];
126 strtab = (char *)tpnt->dynamic_info[DT_STRTAB];
128 for (i = 0; i < rel_size; i++, rpnt++) {
131 symtab_index = ELF_R_SYM(rpnt->r_info);
133 debug_sym(symtab, strtab, symtab_index);
134 debug_reloc(symtab, strtab, rpnt);
136 res = reloc_fnc(tpnt, scope, rpnt, symtab, strtab);
141 _dl_dprintf(2, "\n%s: ", _dl_progname);
144 _dl_dprintf(2, "symbol '%s': ",
145 strtab + symtab[symtab_index].st_name);
147 if (unlikely(res < 0)) {
148 int reloc_type = ELF_R_TYPE(rpnt->r_info);
150 _dl_dprintf(2, "can't handle reloc type "
151 #if defined (__SUPPORT_LD_DEBUG__)
152 "%s\n", _dl_reltypes(reloc_type));
157 } else if (unlikely(res > 0)) {
158 _dl_dprintf(2, "can't resolve symbol\n");
167 _dl_do_reloc(struct elf_resolve *tpnt, struct dyn_elf *scope,
168 ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
173 struct elf_resolve *tls_tpnt = 0;
175 ElfW(Addr) *reloc_addr;
176 ElfW(Addr) symbol_addr;
177 #if defined (__SUPPORT_LD_DEBUG__)
181 reloc_addr = (ElfW(Addr)*)(tpnt->loadaddr + (unsigned long)rpnt->r_offset);
182 reloc_type = ELF_R_TYPE(rpnt->r_info);
183 symtab_index = ELF_R_SYM(rpnt->r_info);
184 sym = &symtab[symtab_index];
186 symname = strtab + sym->st_name;
189 symbol_addr = (ElfW(Addr))_dl_find_hash(symname, scope, tpnt,
190 elf_machine_type_class(reloc_type), &tls_tpnt);
192 * We want to allow undefined references to weak symbols - this
193 * might have been intentional. We should not be linking local
194 * symbols here, so all bases should be covered.
196 if (unlikely(!symbol_addr && (ELF_ST_TYPE(sym->st_info) != STT_TLS)
197 && (ELF_ST_BIND(sym->st_info) != STB_WEAK))) {
198 /* This may be non-fatal if called from dlopen. */
203 /* Relocs against STN_UNDEF are usually treated as using a
204 * symbol value of zero, and using the module containing the
206 symbol_addr = sym->st_value;
210 #if defined (__SUPPORT_LD_DEBUG__)
211 old_val = *reloc_addr;
214 symbol_addr += rpnt->r_addend; /* Assume copy relocs have zero addend. */
216 switch (reloc_type) {
221 *reloc_addr = symbol_addr - (unsigned int) reloc_addr;
226 symbol_addr = tpnt->loadaddr + rpnt->r_addend;
228 symbol_addr += rpnt->r_addend;
229 *reloc_addr = (*reloc_addr & ~0x3ff) | (symbol_addr & 0x3ff);
232 case R_SPARC_GLOB_DAT:
234 *reloc_addr = symbol_addr;
237 case R_SPARC_JMP_SLOT:
238 reloc_addr[1] = OPCODE_SETHI_G1 | (( symbol_addr >> 10 ) & 0x3fffff);
239 reloc_addr[2] = OPCODE_JMP_G1 | ( symbol_addr & 0x3ff );
242 case R_SPARC_RELATIVE:
243 *reloc_addr += tpnt->loadaddr + rpnt->r_addend;
246 case R_SPARC_WDISP30:
247 *reloc_addr = (*reloc_addr & 0xc0000000)|
248 ((symbol_addr - (unsigned int) reloc_addr) >> 2);
253 symbol_addr = tpnt->loadaddr + rpnt->r_addend;
255 symbol_addr += rpnt->r_addend;
256 *reloc_addr = (*reloc_addr & 0xffc00000) | (symbol_addr >> 10);
261 #if defined (__SUPPORT_LD_DEBUG__)
263 _dl_dprintf(_dl_debug_file,
264 "\t%s move %d bytes from %x to %x\n",
265 symname, sym->st_size,
266 symbol_addr, reloc_addr);
269 _dl_memcpy((char *)reloc_addr,
273 _dl_dprintf(_dl_debug_file, "no symbol_addr to copy !?\n");
276 case R_SPARC_TLS_DTPMOD32:
277 *reloc_addr = tls_tpnt->l_tls_modid;
280 case R_SPARC_TLS_DTPOFF32:
281 /* During relocation all TLS symbols are defined and used.
282 * Therefore the offset is already correct. */
283 *reloc_addr = sym->st_value + rpnt->r_addend;
286 case R_SPARC_TLS_TPOFF32:
287 /* The offset is negative, forward from the thread pointer.
288 * We know the offset of the object the symbol is contained in.
289 * It is a negative value which will be added to the
291 CHECK_STATIC_TLS ((struct link_map *) tls_tpnt);
292 *reloc_addr = sym->st_value - tls_tpnt->l_tls_offset + rpnt->r_addend;
296 return -1; /* Calls _dl_exit(1). */
299 #if defined (__SUPPORT_LD_DEBUG__)
300 if (_dl_debug_reloc && _dl_debug_detail)
301 _dl_dprintf(_dl_debug_file, "\tpatched: %x ==> %x @ %x\n",
302 old_val, *reloc_addr, reloc_addr);
308 #undef __SPARC_LAZY_RELOC_WORKS
309 #ifdef __SPARC_LAZY_RELOC_WORKS
311 _dl_do_lazy_reloc(struct elf_resolve *tpnt, struct dyn_elf *scope,
312 ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab)
316 ElfW(Addr) *reloc_addr;
317 #if defined (__SUPPORT_LD_DEBUG__)
322 symtab_index = ELF_R_SYM(rpnt->r_info);
325 reloc_addr = (ElfW(Addr)*)(tpnt->loadaddr + rpnt->r_offset);
326 reloc_type = ELF_R_TYPE(rpnt->r_info);
328 #if defined (__SUPPORT_LD_DEBUG__)
329 old_val = *reloc_addr;
332 switch (reloc_type) {
335 case R_SPARC_JMP_SLOT:
341 #if defined (__SUPPORT_LD_DEBUG__)
342 if (_dl_debug_reloc && _dl_debug_detail)
343 _dl_dprintf(_dl_debug_file, "\tpatched_lazy: %x ==> %x @ %x\n",
344 old_val, *reloc_addr, reloc_addr);
352 _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
353 unsigned long rel_addr,
354 unsigned long rel_size)
356 #ifdef __SPARC_LAZY_RELOC_WORKS
357 (void)_dl_parse(rpnt->dyn, NULL, rel_addr, rel_size, _dl_do_lazy_reloc);
359 _dl_parse_relocation_information(rpnt, rel_addr, rel_size);
364 _dl_parse_relocation_information(struct dyn_elf *rpnt,
365 unsigned long rel_addr,
366 unsigned long rel_size)
368 return _dl_parse(rpnt->dyn, rpnt->dyn->symbol_scope, rel_addr, rel_size, _dl_do_reloc);