1 /* Copyright (C) 2005, 2007, 2008 Red Hat, Inc. 2 This file is part of elfutils. 3 Written by Ulrich Drepper <drepper@redhat.com>, 2005. 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 <string.h> 34 35 #include "libasmP.h" 36 #include "../libebl/libeblP.h" 37 38 39 struct symtoken 40 { 41 DisasmCtx_t *ctx; 42 void *symcbarg; 43 }; 44 45 46 static int default_elf_getsym(GElf_Addr addr,Elf32_Word scnndx,GElf_Addr value,char ** buf,size_t * buflen,void * arg)47 default_elf_getsym (GElf_Addr addr, Elf32_Word scnndx, GElf_Addr value, 48 char **buf, size_t *buflen, void *arg) 49 { 50 struct symtoken *symtoken = (struct symtoken *) arg; 51 52 /* First try the user provided function. */ 53 if (symtoken->ctx->symcb != NULL) 54 { 55 int res = symtoken->ctx->symcb (addr, scnndx, value, buf, buflen, 56 symtoken->symcbarg); 57 if (res >= 0) 58 return res; 59 } 60 61 // XXX Look up in ELF file. 62 63 return -1; 64 } 65 66 67 struct symaddrpair 68 { 69 GElf_Addr addr; 70 const char *name; 71 }; 72 73 74 static void read_symtab_exec(DisasmCtx_t * ctx)75 read_symtab_exec (DisasmCtx_t *ctx) 76 { 77 /* We simply use all we can get our hands on. This will produce 78 some duplicate information but this is no problem, we simply 79 ignore the latter definitions. */ 80 Elf_Scn *scn= NULL; 81 while ((scn = elf_nextscn (ctx->elf, scn)) != NULL) 82 { 83 GElf_Shdr shdr_mem; 84 GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); 85 Elf_Data *data; 86 if (shdr == NULL || shdr->sh_type != SHT_SYMTAB 87 || (data = elf_getdata (scn, NULL)) == NULL) 88 continue; 89 90 int xndxscnidx = elf_scnshndx (scn); 91 Elf_Data *xndxdata = NULL; 92 if (xndxscnidx > 0) 93 xndxdata = elf_getdata (elf_getscn (ctx->elf, xndxscnidx), NULL); 94 95 /* Iterate over all symbols. Add all defined symbols. */ 96 if (shdr->sh_entsize == 0) 97 continue; 98 int nsyms = shdr->sh_size / shdr->sh_entsize; 99 for (int cnt = 1; cnt < nsyms; ++cnt) 100 { 101 Elf32_Word xshndx; 102 GElf_Sym sym_mem; 103 GElf_Sym *sym = gelf_getsymshndx (data, xndxdata, cnt, &sym_mem, 104 &xshndx); 105 if (sym == NULL) 106 continue; 107 108 /* Undefined symbols are useless here. */ 109 if (sym->st_shndx == SHN_UNDEF) 110 continue; 111 112 113 } 114 } 115 } 116 117 118 static void read_symtab(DisasmCtx_t * ctx)119 read_symtab (DisasmCtx_t *ctx) 120 { 121 /* Find the symbol table(s). */ 122 GElf_Ehdr ehdr_mem; 123 GElf_Ehdr *ehdr = gelf_getehdr (ctx->elf, &ehdr_mem); 124 if (ehdr == NULL) 125 return; 126 127 switch (ehdr->e_type) 128 { 129 case ET_EXEC: 130 case ET_DYN: 131 read_symtab_exec (ctx); 132 break; 133 134 case ET_REL: 135 // XXX Handle 136 break; 137 138 default: 139 break; 140 } 141 } 142 143 144 static int null_elf_getsym(GElf_Addr addr,Elf32_Word scnndx,GElf_Addr value,char ** buf,size_t * buflen,void * arg)145 null_elf_getsym (GElf_Addr addr __attribute__ ((unused)), 146 Elf32_Word scnndx __attribute__ ((unused)), 147 GElf_Addr value __attribute__ ((unused)), 148 char **buf __attribute__ ((unused)), 149 size_t *buflen __attribute__ ((unused)), 150 void *arg __attribute__ ((unused))) 151 { 152 return -1; 153 } 154 155 156 int disasm_cb(DisasmCtx_t * ctx,const uint8_t ** startp,const uint8_t * end,GElf_Addr addr,const char * fmt,DisasmOutputCB_t outcb,void * outcbarg,void * symcbarg)157 disasm_cb (DisasmCtx_t *ctx, const uint8_t **startp, const uint8_t *end, 158 GElf_Addr addr, const char *fmt, DisasmOutputCB_t outcb, 159 void *outcbarg, void *symcbarg) 160 { 161 struct symtoken symtoken; 162 DisasmGetSymCB_t getsym = ctx->symcb ?: null_elf_getsym; 163 164 if (ctx->elf != NULL) 165 { 166 /* Read all symbols of the ELF file and stuff them into a hash 167 table. The key is the address and the section index. */ 168 read_symtab (ctx); 169 170 symtoken.ctx = ctx; 171 symtoken.symcbarg = symcbarg; 172 173 symcbarg = &symtoken; 174 175 getsym = default_elf_getsym; 176 } 177 178 return ctx->ebl->disasm (ctx->ebl, startp, end, addr, fmt, outcb, 179 getsym, outcbarg, symcbarg); 180 } 181 INTDEF (disasm_cb) 182