1 // Copyright (c) 2007, Google Inc. 2 // All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 // file_id.cc: Return a unique identifier for a file 31 // 32 // See file_id.h for documentation 33 // 34 // Author: Alfred Peng 35 36 #include <elf.h> 37 #include <fcntl.h> 38 #include <gelf.h> 39 #include <sys/mman.h> 40 #include <sys/ksyms.h> 41 #include <stdio.h> 42 #include <string.h> 43 #include <unistd.h> 44 45 #include <cassert> 46 #include <cstdio> 47 48 #include "common/md5.h" 49 #include "common/solaris/file_id.h" 50 #include "common/solaris/message_output.h" 51 #include "google_breakpad/common/minidump_format.h" 52 53 namespace google_breakpad { 54 55 class AutoElfEnder { 56 public: 57 AutoElfEnder(Elf *elf) : elf_(elf) {} 58 ~AutoElfEnder() { if (elf_) elf_end(elf_); } 59 private: 60 Elf *elf_; 61 }; 62 63 // Find the text section in elf object file. 64 // Return the section start address and the size. 65 static bool FindElfTextSection(int fd, const void *elf_base, 66 const void **text_start, 67 int *text_size) { 68 assert(text_start); 69 assert(text_size); 70 71 *text_start = NULL; 72 *text_size = 0; 73 74 if (elf_version(EV_CURRENT) == EV_NONE) { 75 print_message2(2, "elf_version() failed: %s\n", elf_errmsg(0)); 76 return false; 77 } 78 79 GElf_Ehdr elf_header; 80 lseek(fd, 0L, 0); 81 Elf *elf = elf_begin(fd, ELF_C_READ, NULL); 82 AutoElfEnder elfEnder(elf); 83 84 if (gelf_getehdr(elf, &elf_header) == (GElf_Ehdr *)NULL) { 85 print_message2(2, "failed to read elf header: %s\n", elf_errmsg(-1)); 86 return false; 87 } 88 89 if (elf_header.e_ident[EI_MAG0] != ELFMAG0 || 90 elf_header.e_ident[EI_MAG1] != ELFMAG1 || 91 elf_header.e_ident[EI_MAG2] != ELFMAG2 || 92 elf_header.e_ident[EI_MAG3] != ELFMAG3) { 93 print_message1(2, "header magic doesn't match\n"); 94 return false; 95 } 96 97 static const char kTextSectionName[] = ".text"; 98 const GElf_Shdr *text_section = NULL; 99 Elf_Scn *scn = NULL; 100 GElf_Shdr shdr; 101 102 while ((scn = elf_nextscn(elf, scn)) != NULL) { 103 if (gelf_getshdr(scn, &shdr) == (GElf_Shdr *)0) { 104 print_message2(2, "failed to read section header: %s\n", elf_errmsg(0)); 105 return false; 106 } 107 108 if (shdr.sh_type == SHT_PROGBITS) { 109 const char *section_name = elf_strptr(elf, elf_header.e_shstrndx, 110 shdr.sh_name); 111 if (!section_name) { 112 print_message2(2, "Section name error: %s\n", elf_errmsg(-1)); 113 continue; 114 } 115 116 if (strcmp(section_name, kTextSectionName) == 0) { 117 text_section = &shdr; 118 break; 119 } 120 } 121 } 122 if (text_section != NULL && text_section->sh_size > 0) { 123 *text_start = (char *)elf_base + text_section->sh_offset; 124 *text_size = text_section->sh_size; 125 return true; 126 } 127 128 return false; 129 } 130 131 FileID::FileID(const char *path) { 132 strcpy(path_, path); 133 } 134 135 class AutoCloser { 136 public: 137 AutoCloser(int fd) : fd_(fd) {} 138 ~AutoCloser() { if (fd_) close(fd_); } 139 private: 140 int fd_; 141 }; 142 143 bool FileID::ElfFileIdentifier(unsigned char identifier[16]) { 144 int fd = 0; 145 if ((fd = open(path_, O_RDONLY)) < 0) 146 return false; 147 148 AutoCloser autocloser(fd); 149 struct stat st; 150 if (fstat(fd, &st) != 0 || st.st_size <= 0) 151 return false; 152 153 void *base = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0); 154 if (base == MAP_FAILED) 155 return false; 156 157 bool success = false; 158 const void *text_section = NULL; 159 int text_size = 0; 160 161 if (FindElfTextSection(fd, base, &text_section, &text_size)) { 162 MD5Context md5; 163 MD5Init(&md5); 164 MD5Update(&md5, (const unsigned char *)text_section, text_size); 165 MD5Final(identifier, &md5); 166 success = true; 167 } 168 169 munmap((char *)base, st.st_size); 170 return success; 171 } 172 173 // static 174 bool FileID::ConvertIdentifierToString(const unsigned char identifier[16], 175 char *buffer, int buffer_length) { 176 if (buffer_length < 34) 177 return false; 178 179 int buffer_idx = 0; 180 for (int idx = 0; idx < 16; ++idx) { 181 int hi = (identifier[idx] >> 4) & 0x0F; 182 int lo = (identifier[idx]) & 0x0F; 183 184 buffer[buffer_idx++] = (hi >= 10) ? 'A' + hi - 10 : '0' + hi; 185 buffer[buffer_idx++] = (lo >= 10) ? 'A' + lo - 10 : '0' + lo; 186 } 187 188 // Add an extra "0" by the end. 189 buffer[buffer_idx++] = '0'; 190 191 // NULL terminate 192 buffer[buffer_idx] = 0; 193 194 return true; 195 } 196 197 } // namespace google_breakpad 198
