usr.sbin/lockstat/elf32.c

   1 /*      $NetBSD: elf32.c,v 1.7 2008/04/28 20:24:16 martin Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2006 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Andrew Doran.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Copyright (c) 1996 Christopher G. Demetriou
  34  * All rights reserved.
  35  *
  36  * Redistribution and use in source and binary forms, with or without
  37  * modification, are permitted provided that the following conditions
  38  * are met:
  39  * 1. Redistributions of source code must retain the above copyright
  40  *    notice, this list of conditions and the following disclaimer.
  41  * 2. Redistributions in binary form must reproduce the above copyright
  42  *    notice, this list of conditions and the following disclaimer in the
  43  *    documentation and/or other materials provided with the distribution.
  44  * 3. All advertising materials mentioning features or use of this software
  45  *    must display the following acknowledgement:
  46  *          This product includes software developed for the
  47  *          NetBSD Project.  See http://www.NetBSD.org/ for
  48  *          information about NetBSD.
  49  * 4. The name of the author may not be used to endorse or promote products
  50  *    derived from this software without specific prior written permission.
  51  *
  52  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  53  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  54  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  55  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  56  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  57  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  58  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  59  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  60  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  61  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  62  *
  63  * <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
  64  */
  65
  66 #include <sys/cdefs.h>
  67 #if !defined(lint)
  68 __RCSID("$NetBSD: elf32.c,v 1.7 2008/04/28 20:24:16 martin Exp $");
  69 #endif
  70
  71 #ifndef ELFSIZE
  72 #define ELFSIZE         32
  73 #endif
  74
  75 #include <sys/param.h>
  76 #include <sys/exec_elf.h>
  77 #include <sys/queue.h>
  78
  79 #include <dev/lockstat.h>
  80
  81 #include <stdio.h>
  82 #include <stdlib.h>
  83 #include <string.h>
  84 #include <unistd.h>
  85 #include <err.h>
  86
  87 #include "extern.h"
  88
  89 #if (ELFSIZE == 32)
  90 #define NAME(x) x##32
  91 #elif (ELFSIZE == 64)
  92 #define NAME(x) x##64
  93 #endif
  94
  95 static int              nsyms;
  96 static Elf_Sym          *symp;
  97 static char             *strp;
  98
  99 int
 100 NAME(loadsym)(int fd)
 101 {
 102         Elf_Shdr symhdr, strhdr;
 103         Elf_Ehdr ehdr;
 104         size_t sz;
 105         off_t off;
 106         int i;
 107
 108         /*
 109          * Read the ELF header and make sure it's OK.
 110          */
 111         if (pread(fd, &ehdr, sizeof(ehdr), 0) != sizeof(ehdr))
 112                 return -1;
 113
 114         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
 115             ehdr.e_ident[EI_CLASS] != ELFCLASS)
 116                 return -1;
 117
 118         switch (ehdr.e_machine) {
 119         ELFDEFNNAME(MACHDEP_ID_CASES)
 120         default:
 121                 return -1;
 122         }
 123
 124         /*
 125          * Find the symbol table header, and make sure the binary isn't
 126          * stripped.
 127          */
 128         off = ehdr.e_shoff;
 129         for (i = 0; i < ehdr.e_shnum; i++, off += sizeof(symhdr)) {
 130                 sz = pread(fd, &symhdr, sizeof(symhdr), off);
 131                 if (sz != sizeof(symhdr))
 132                         err(EXIT_FAILURE, "pread (section headers)");
 133                 if (symhdr.sh_type == SHT_SYMTAB)
 134                         break;
 135         }
 136         if (i == ehdr.e_shnum || symhdr.sh_offset == 0)
 137                 err(EXIT_FAILURE, "namelist is stripped");
 138
 139         /*
 140          * Pull in the string table header, and then read in both the symbol
 141          * table and string table proper.
 142          *
 143          * XXX We can't use mmap(), as /dev/ksyms doesn't support mmap yet.
 144          */
 145         off = ehdr.e_shoff + symhdr.sh_link * sizeof(symhdr);
 146         if (pread(fd, &strhdr, sizeof(strhdr), off) != sizeof(strhdr))
 147                 err(EXIT_FAILURE, "pread");
 148
 149         if ((symp = malloc(symhdr.sh_size)) == NULL)
 150                 err(EXIT_FAILURE, "malloc (symbol table)");
 151         sz = pread(fd, symp, symhdr.sh_size, symhdr.sh_offset   );
 152         if (sz != symhdr.sh_size)
 153                 err(EXIT_FAILURE, "pread (symbol table)");
 154
 155         if ((strp = malloc(strhdr.sh_size)) == NULL)
 156                 err(EXIT_FAILURE, "malloc (string table)");
 157         sz = pread(fd, strp, strhdr.sh_size, strhdr.sh_offset);
 158         if (sz != strhdr.sh_size)
 159                 err(EXIT_FAILURE, "pread (string table)");
 160
 161         nsyms = (int)(symhdr.sh_size / sizeof(Elf_Sym));
 162
 163         return 0;
 164 }
 165
 166 int
 167 NAME(findsym)(findsym_t find, char *name, uintptr_t *start, uintptr_t *end)
 168 {
 169         static int lastptr[FIND_MAX];
 170         uintptr_t sa, ea;
 171         int i, rv, off;
 172         Elf_Byte st;
 173
 174         switch (find) {
 175         case LOCK_BYNAME:
 176         case LOCK_BYADDR:
 177                 st = STT_OBJECT;
 178                 break;
 179         case FUNC_BYNAME:
 180         case FUNC_BYADDR:
 181                 st = STT_FUNC;
 182                 break;
 183         default:
 184                 return -1;
 185         }
 186
 187         rv = -1;
 188
 189 #ifdef dump_core
 190         for (i = lastptr[find];;) {
 191 #else
 192         for (i = 0; i < nsyms; i++) {
 193 #endif
 194                 switch (find) {
 195                 case LOCK_BYNAME:
 196                 case FUNC_BYNAME:
 197                         if (ELF_ST_TYPE(symp[i].st_info) != st)
 198                                 break;
 199                         if (strcmp(&strp[symp[i].st_name], name) != 0)
 200                                 break;
 201                         *start = (uintptr_t)symp[i].st_value;
 202                         *end = *start + (uintptr_t)symp[i].st_size;
 203                         goto found;
 204
 205                 case LOCK_BYADDR:
 206                 case FUNC_BYADDR:
 207                         if (ELF_ST_TYPE(symp[i].st_info) != st)
 208                                 break;
 209                         sa = (uintptr_t)symp[i].st_value;
 210                         ea = sa + (uintptr_t)symp[i].st_size - 1;
 211                         if (*start < sa || *start > ea)
 212                                 break;
 213                         off = (int)(*start - sa);
 214                         *start = sa;
 215                         if (end != NULL)
 216                                 *end = ea;
 217                         if (name == NULL)
 218                                 goto found;
 219                         if (off == 0)
 220                                 strlcpy(name, &strp[symp[i].st_name],
 221                                     NAME_SIZE);
 222                         else
 223                                 snprintf(name, NAME_SIZE, "%s+%x",
 224                                     &strp[symp[i].st_name], off);
 225                         goto found;
 226
 227                 default:
 228                         break;
 229                 }
 230
 231 #ifdef dump_core
 232                 if (++i >= nsyms)
 233                         i = 0;
 234                 if (i == lastptr[find])
 235                         return -1;
 236 #endif
 237         }
 238
 239         return -1;
 240
 241  found:
 242         lastptr[find] = i;
 243         return 0;
 244 }