Line data Source code
1 : /* Find debugging and symbol information for a module in libdwfl.
2 : Copyright (C) 2006-2014 Red Hat, Inc.
3 : This file is part of elfutils.
4 :
5 : This file is free software; you can redistribute it and/or modify
6 : it under the terms of either
7 :
8 : * the GNU Lesser General Public License as published by the Free
9 : Software Foundation; either version 3 of the License, or (at
10 : your option) any later version
11 :
12 : or
13 :
14 : * the GNU General Public License as published by the Free
15 : Software Foundation; either version 2 of the License, or (at
16 : your option) any later version
17 :
18 : or both in parallel, as here.
19 :
20 : elfutils is distributed in the hope that it will be useful, but
21 : WITHOUT ANY WARRANTY; without even the implied warranty of
22 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 : General Public License for more details.
24 :
25 : You should have received copies of the GNU General Public License and
26 : the GNU Lesser General Public License along with this program. If
27 : not, see <http://www.gnu.org/licenses/>. */
28 :
29 : #ifdef HAVE_CONFIG_H
30 : # include <config.h>
31 : #endif
32 :
33 : #include "libdwflP.h"
34 :
35 : const char *
36 : internal_function
37 753131362 : __libdwfl_getsym (Dwfl_Module *mod, int ndx, GElf_Sym *sym, GElf_Addr *addr,
38 : GElf_Word *shndxp, Elf **elfp, Dwarf_Addr *biasp,
39 : bool *resolved, bool adjust_st_value)
40 : {
41 753131362 : if (unlikely (mod == NULL))
42 : return NULL;
43 :
44 753131362 : if (unlikely (mod->symdata == NULL))
45 : {
46 35 : int result = INTUSE(dwfl_module_getsymtab) (mod);
47 35 : if (result < 0)
48 : return NULL;
49 : }
50 :
51 : /* All local symbols should come before all global symbols. If we
52 : have an auxiliary table make sure all the main locals come first,
53 : then all aux locals, then all main globals and finally all aux globals.
54 : And skip the auxiliary table zero undefined entry. */
55 : GElf_Word shndx;
56 753131362 : int tndx = ndx;
57 753131362 : int skip_aux_zero = (mod->syments > 0 && mod->aux_syments > 0) ? 1 : 0;
58 : Elf *elf;
59 : Elf_Data *symdata;
60 : Elf_Data *symxndxdata;
61 : Elf_Data *symstrdata;
62 753131362 : if (mod->aux_symdata == NULL
63 2105 : || ndx < mod->first_global)
64 : {
65 : /* main symbol table (locals). */
66 753129304 : tndx = ndx;
67 753129304 : elf = mod->symfile->elf;
68 753129304 : symdata = mod->symdata;
69 753129304 : symxndxdata = mod->symxndxdata;
70 753129304 : symstrdata = mod->symstrdata;
71 : }
72 2058 : else if (ndx < mod->first_global + mod->aux_first_global - skip_aux_zero)
73 : {
74 : /* aux symbol table (locals). */
75 1188 : tndx = ndx - mod->first_global + skip_aux_zero;
76 1188 : elf = mod->aux_sym.elf;
77 1188 : symdata = mod->aux_symdata;
78 1188 : symxndxdata = mod->aux_symxndxdata;
79 1188 : symstrdata = mod->aux_symstrdata;
80 : }
81 870 : else if ((size_t) ndx < mod->syments + mod->aux_first_global - skip_aux_zero)
82 : {
83 : /* main symbol table (globals). */
84 586 : tndx = ndx - mod->aux_first_global + skip_aux_zero;
85 586 : elf = mod->symfile->elf;
86 586 : symdata = mod->symdata;
87 586 : symxndxdata = mod->symxndxdata;
88 586 : symstrdata = mod->symstrdata;
89 : }
90 : else
91 : {
92 : /* aux symbol table (globals). */
93 284 : tndx = ndx - mod->syments + skip_aux_zero;
94 284 : elf = mod->aux_sym.elf;
95 284 : symdata = mod->aux_symdata;
96 284 : symxndxdata = mod->aux_symxndxdata;
97 284 : symstrdata = mod->aux_symstrdata;
98 : }
99 753131362 : sym = gelf_getsymshndx (symdata, symxndxdata, tndx, sym, &shndx);
100 :
101 753131362 : if (unlikely (sym == NULL))
102 : {
103 0 : __libdwfl_seterrno (DWFL_E_LIBELF);
104 0 : return NULL;
105 : }
106 :
107 753131362 : if (sym->st_shndx != SHN_XINDEX)
108 753131362 : shndx = sym->st_shndx;
109 :
110 : /* Figure out whether this symbol points into an SHF_ALLOC section. */
111 753131362 : bool alloc = true;
112 753131362 : if ((shndxp != NULL || mod->e_type != ET_REL)
113 753131362 : && (sym->st_shndx == SHN_XINDEX
114 753131362 : || (sym->st_shndx < SHN_LORESERVE && sym->st_shndx != SHN_UNDEF)))
115 : {
116 : GElf_Shdr shdr_mem;
117 625601937 : GElf_Shdr *shdr = gelf_getshdr (elf_getscn (elf, shndx), &shdr_mem);
118 625601937 : alloc = unlikely (shdr == NULL) || (shdr->sh_flags & SHF_ALLOC);
119 : }
120 :
121 : /* In case of an value in an allocated section the main Elf Ebl
122 : might know where the real value is (e.g. for function
123 : descriptors). */
124 :
125 : char *ident;
126 753131362 : GElf_Addr st_value = sym->st_value & ebl_func_addr_mask (mod->ebl);
127 753131362 : *resolved = false;
128 753131362 : if (! adjust_st_value && mod->e_type != ET_REL && alloc
129 743108310 : && (GELF_ST_TYPE (sym->st_info) == STT_FUNC
130 418976906 : || (GELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC
131 2523 : && (ident = elf_getident (elf, NULL)) != NULL
132 2523 : && ident[EI_OSABI] == ELFOSABI_LINUX)))
133 : {
134 324133927 : if (likely (__libdwfl_module_getebl (mod) == DWFL_E_NOERROR))
135 : {
136 324133927 : if (elf != mod->main.elf)
137 : {
138 3420 : st_value = dwfl_adjusted_st_value (mod, elf, st_value);
139 3420 : st_value = dwfl_deadjust_st_value (mod, mod->main.elf, st_value);
140 : }
141 :
142 324133927 : *resolved = ebl_resolve_sym_value (mod->ebl, &st_value);
143 324133927 : if (! *resolved)
144 324133212 : st_value = sym->st_value;
145 : }
146 : }
147 :
148 753131362 : if (shndxp != NULL)
149 : /* Yield -1 in case of a non-SHF_ALLOC section. */
150 753129230 : *shndxp = alloc ? shndx : (GElf_Word) -1;
151 :
152 753131362 : switch (sym->st_shndx)
153 : {
154 : case SHN_ABS: /* XXX sometimes should use bias?? */
155 : case SHN_UNDEF:
156 : case SHN_COMMON:
157 : break;
158 :
159 : default:
160 625601937 : if (mod->e_type == ET_REL)
161 : {
162 : /* In an ET_REL file, the symbol table values are relative
163 : to the section, not to the module's load base. */
164 3460314 : size_t symshstrndx = SHN_UNDEF;
165 3460314 : Dwfl_Error result = __libdwfl_relocate_value (mod, elf,
166 : &symshstrndx,
167 : shndx, &st_value);
168 3460314 : if (unlikely (result != DWFL_E_NOERROR))
169 : {
170 0 : __libdwfl_seterrno (result);
171 0 : return NULL;
172 : }
173 : }
174 622141623 : else if (alloc)
175 : /* Apply the bias to the symbol value. */
176 1858737768 : st_value = dwfl_adjusted_st_value (mod,
177 619579256 : *resolved ? mod->main.elf : elf,
178 : st_value);
179 : break;
180 : }
181 :
182 753131362 : if (adjust_st_value)
183 1232 : sym->st_value = st_value;
184 :
185 753131362 : if (addr != NULL)
186 753130130 : *addr = st_value;
187 :
188 753131362 : if (unlikely (sym->st_name >= symstrdata->d_size))
189 : {
190 0 : __libdwfl_seterrno (DWFL_E_BADSTROFF);
191 0 : return NULL;
192 : }
193 753131362 : if (elfp)
194 753127998 : *elfp = elf;
195 753131362 : if (biasp)
196 1232 : *biasp = dwfl_adjusted_st_value (mod, elf, 0);
197 753131362 : return (const char *) symstrdata->d_buf + sym->st_name;
198 : }
199 :
200 : const char *
201 3364 : dwfl_module_getsym_info (Dwfl_Module *mod, int ndx,
202 : GElf_Sym *sym, GElf_Addr *addr,
203 : GElf_Word *shndxp,
204 : Elf **elfp, Dwarf_Addr *bias)
205 : {
206 : bool resolved;
207 3364 : return __libdwfl_getsym (mod, ndx, sym, addr, shndxp, elfp, bias,
208 : &resolved, false);
209 : }
210 : INTDEF (dwfl_module_getsym_info)
211 :
212 : const char *
213 1232 : dwfl_module_getsym (Dwfl_Module *mod, int ndx,
214 : GElf_Sym *sym, GElf_Word *shndxp)
215 : {
216 : bool resolved;
217 1232 : return __libdwfl_getsym (mod, ndx, sym, NULL, shndxp, NULL, NULL,
218 : &resolved, true);
219 : }
220 : INTDEF (dwfl_module_getsym)
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