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 : #include "libdwflP.h"
30 :
31 : const char *
32 : internal_function
33 675065443 : __libdwfl_getsym (Dwfl_Module *mod, int ndx, GElf_Sym *sym, GElf_Addr *addr,
34 : GElf_Word *shndxp, Elf **elfp, Dwarf_Addr *biasp,
35 : bool *resolved, bool adjust_st_value)
36 : {
37 675065443 : if (unlikely (mod == NULL))
38 : return NULL;
39 :
40 675065443 : if (unlikely (mod->symdata == NULL))
41 : {
42 35 : int result = INTUSE(dwfl_module_getsymtab) (mod);
43 35 : if (result < 0)
44 : return NULL;
45 : }
46 :
47 : /* All local symbols should come before all global symbols. If we
48 : have an auxiliary table make sure all the main locals come first,
49 : then all aux locals, then all main globals and finally all aux globals.
50 : And skip the auxiliary table zero undefined entry. */
51 : GElf_Word shndx;
52 675065443 : int tndx = ndx;
53 675065443 : int skip_aux_zero = (mod->syments > 0 && mod->aux_syments > 0) ? 1 : 0;
54 : Elf *elf;
55 : Elf_Data *symdata;
56 : Elf_Data *symxndxdata;
57 : Elf_Data *symstrdata;
58 675065443 : if (mod->aux_symdata == NULL
59 2105 : || ndx < mod->first_global)
60 : {
61 : /* main symbol table (locals). */
62 675063385 : tndx = ndx;
63 675063385 : elf = mod->symfile->elf;
64 675063385 : symdata = mod->symdata;
65 675063385 : symxndxdata = mod->symxndxdata;
66 675063385 : symstrdata = mod->symstrdata;
67 : }
68 2058 : else if (ndx < mod->first_global + mod->aux_first_global - skip_aux_zero)
69 : {
70 : /* aux symbol table (locals). */
71 1188 : tndx = ndx - mod->first_global + skip_aux_zero;
72 1188 : elf = mod->aux_sym.elf;
73 1188 : symdata = mod->aux_symdata;
74 1188 : symxndxdata = mod->aux_symxndxdata;
75 1188 : symstrdata = mod->aux_symstrdata;
76 : }
77 870 : else if ((size_t) ndx < mod->syments + mod->aux_first_global - skip_aux_zero)
78 : {
79 : /* main symbol table (globals). */
80 586 : tndx = ndx - mod->aux_first_global + skip_aux_zero;
81 586 : elf = mod->symfile->elf;
82 586 : symdata = mod->symdata;
83 586 : symxndxdata = mod->symxndxdata;
84 586 : symstrdata = mod->symstrdata;
85 : }
86 : else
87 : {
88 : /* aux symbol table (globals). */
89 284 : tndx = ndx - mod->syments + skip_aux_zero;
90 284 : elf = mod->aux_sym.elf;
91 284 : symdata = mod->aux_symdata;
92 284 : symxndxdata = mod->aux_symxndxdata;
93 284 : symstrdata = mod->aux_symstrdata;
94 : }
95 675065443 : sym = gelf_getsymshndx (symdata, symxndxdata, tndx, sym, &shndx);
96 :
97 675065443 : if (unlikely (sym == NULL))
98 : {
99 0 : __libdwfl_seterrno (DWFL_E_LIBELF);
100 0 : return NULL;
101 : }
102 :
103 675065443 : if (sym->st_shndx != SHN_XINDEX)
104 675065443 : shndx = sym->st_shndx;
105 :
106 : /* Figure out whether this symbol points into an SHF_ALLOC section. */
107 675065443 : bool alloc = true;
108 675065443 : if ((shndxp != NULL || mod->e_type != ET_REL)
109 675065443 : && (sym->st_shndx == SHN_XINDEX
110 675065443 : || (sym->st_shndx < SHN_LORESERVE && sym->st_shndx != SHN_UNDEF)))
111 : {
112 : GElf_Shdr shdr_mem;
113 558497356 : GElf_Shdr *shdr = gelf_getshdr (elf_getscn (elf, shndx), &shdr_mem);
114 558497356 : alloc = unlikely (shdr == NULL) || (shdr->sh_flags & SHF_ALLOC);
115 : }
116 :
117 : /* In case of an value in an allocated section the main Elf Ebl
118 : might know where the real value is (e.g. for function
119 : descriptors). */
120 :
121 : char *ident;
122 675065443 : GElf_Addr st_value = sym->st_value & ebl_func_addr_mask (mod->ebl);
123 675065443 : *resolved = false;
124 675065443 : if (! adjust_st_value && mod->e_type != ET_REL && alloc
125 666893989 : && (GELF_ST_TYPE (sym->st_info) == STT_FUNC
126 368934105 : || (GELF_ST_TYPE (sym->st_info) == STT_GNU_IFUNC
127 1632 : && (ident = elf_getident (elf, NULL)) != NULL
128 1632 : && ident[EI_OSABI] == ELFOSABI_LINUX)))
129 : {
130 297961476 : if (likely (__libdwfl_module_getebl (mod) == DWFL_E_NOERROR))
131 : {
132 297961476 : if (elf != mod->main.elf)
133 : {
134 3420 : st_value = dwfl_adjusted_st_value (mod, elf, st_value);
135 3420 : st_value = dwfl_deadjust_st_value (mod, mod->main.elf, st_value);
136 : }
137 :
138 297961476 : *resolved = ebl_resolve_sym_value (mod->ebl, &st_value);
139 297961476 : if (! *resolved)
140 297960855 : st_value = sym->st_value;
141 : }
142 : }
143 :
144 675065443 : if (shndxp != NULL)
145 : /* Yield -1 in case of a non-SHF_ALLOC section. */
146 675063310 : *shndxp = alloc ? shndx : (GElf_Word) -1;
147 :
148 675065443 : switch (sym->st_shndx)
149 : {
150 : case SHN_ABS: /* XXX sometimes should use bias?? */
151 : case SHN_UNDEF:
152 : case SHN_COMMON:
153 : break;
154 :
155 : default:
156 558497356 : if (mod->e_type == ET_REL)
157 : {
158 : /* In an ET_REL file, the symbol table values are relative
159 : to the section, not to the module's load base. */
160 2394041 : size_t symshstrndx = SHN_UNDEF;
161 2394041 : Dwfl_Error result = __libdwfl_relocate_value (mod, elf,
162 : &symshstrndx,
163 : shndx, &st_value);
164 2394041 : if (unlikely (result != DWFL_E_NOERROR))
165 : {
166 0 : __libdwfl_seterrno (result);
167 0 : return NULL;
168 : }
169 : }
170 556103315 : else if (alloc)
171 : /* Apply the bias to the symbol value. */
172 1660653072 : st_value = dwfl_adjusted_st_value (mod,
173 553551024 : *resolved ? mod->main.elf : elf,
174 : st_value);
175 : break;
176 : }
177 :
178 675065443 : if (adjust_st_value)
179 1232 : sym->st_value = st_value;
180 :
181 675065443 : if (addr != NULL)
182 675064211 : *addr = st_value;
183 :
184 675065443 : if (unlikely (sym->st_name >= symstrdata->d_size))
185 : {
186 0 : __libdwfl_seterrno (DWFL_E_BADSTROFF);
187 0 : return NULL;
188 : }
189 675065443 : if (elfp)
190 675062078 : *elfp = elf;
191 675065443 : if (biasp)
192 1232 : *biasp = dwfl_adjusted_st_value (mod, elf, 0);
193 675065443 : return (const char *) symstrdata->d_buf + sym->st_name;
194 : }
195 :
196 : const char *
197 3365 : dwfl_module_getsym_info (Dwfl_Module *mod, int ndx,
198 : GElf_Sym *sym, GElf_Addr *addr,
199 : GElf_Word *shndxp,
200 : Elf **elfp, Dwarf_Addr *bias)
201 : {
202 : bool resolved;
203 3365 : return __libdwfl_getsym (mod, ndx, sym, addr, shndxp, elfp, bias,
204 : &resolved, false);
205 : }
206 : INTDEF (dwfl_module_getsym_info)
207 :
208 : const char *
209 1232 : dwfl_module_getsym (Dwfl_Module *mod, int ndx,
210 : GElf_Sym *sym, GElf_Word *shndxp)
211 : {
212 : bool resolved;
213 1232 : return __libdwfl_getsym (mod, ndx, sym, NULL, shndxp, NULL, NULL,
214 : &resolved, true);
215 : }
216 : INTDEF (dwfl_module_getsym)
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