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 // Copyright (c) 2007, Google Inc.

 // All rights reserved.

 //

 // Redistribution and use in source and binary forms, with or without

 // modification, are permitted provided that the following conditions are

 // met:

 //

 //     * Redistributions of source code must retain the above copyright

 // notice, this list of conditions and the following disclaimer.

 //     * Redistributions in binary form must reproduce the above

 // copyright notice, this list of conditions and the following disclaimer

 // in the documentation and/or other materials provided with the

 // distribution.

 //     * Neither the name of Google Inc. nor the names of its

 // contributors may be used to endorse or promote products derived from

 // this software without specific prior written permission.

 //

 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 // file_id.cc: Return a unique identifier for a file

 //

 // See file_id.h for documentation

 //

 // Author: Alfred Peng

 #include <elf.h>

 #include <fcntl.h>

 #include <gelf.h>

 #include <sys/mman.h>

 #include <sys/ksyms.h>

 #include <stdio.h>

 #include <string.h>

 #include <unistd.h>

 #include <cassert>

 #include <cstdio>

 #include "common/md5.h"

 #include "common/solaris/file_id.h"

 #include "common/solaris/message_output.h"

 #include "google_breakpad/common/minidump_format.h"

 namespace google_breakpad {

 class AutoElfEnder {

  public:

   AutoElfEnder(Elf *elf) : elf_(elf) {}

   ~AutoElfEnder() { if (elf_) elf_end(elf_); }

  private:

   Elf *elf_;

 };

 // Find the text section in elf object file.

 // Return the section start address and the size.

 static bool FindElfTextSection(int fd, const void *elf_base,

                                const void **text_start,

                                int *text_size) {

   assert(text_start);

   assert(text_size);

   *text_start = NULL;

   *text_size = 0;

   if (elf_version(EV_CURRENT) == EV_NONE) {

     print_message2(2, "elf_version() failed: %s\n", elf_errmsg(0));

     return false;

   }

   GElf_Ehdr elf_header;

   lseek(fd, 0L, 0);

   Elf *elf = elf_begin(fd, ELF_C_READ, NULL);

   AutoElfEnder elfEnder(elf);

   if (gelf_getehdr(elf, &elf_header) == (GElf_Ehdr *)NULL) {

     print_message2(2, "failed to read elf header: %s\n", elf_errmsg(-1));

     return false;

   }

   if (elf_header.e_ident[EI_MAG0] != ELFMAG0 ||

       elf_header.e_ident[EI_MAG1] != ELFMAG1 ||

       elf_header.e_ident[EI_MAG2] != ELFMAG2 ||

       elf_header.e_ident[EI_MAG3] != ELFMAG3) {

     print_message1(2, "header magic doesn't match\n");

     return false;

   }

   static const char kTextSectionName[] = ".text";

   const GElf_Shdr *text_section = NULL;

   Elf_Scn *scn = NULL;

   GElf_Shdr shdr;

   while ((scn = elf_nextscn(elf, scn)) != NULL) {

     if (gelf_getshdr(scn, &shdr) == (GElf_Shdr *)0) {

       print_message2(2, "failed to read section header: %s\n", elf_errmsg(0));

       return false;

     }

     if (shdr.sh_type == SHT_PROGBITS) {

       const char *section_name = elf_strptr(elf, elf_header.e_shstrndx,

                                             shdr.sh_name);

       if (!section_name) {

         print_message2(2, "Section name error: %s\n", elf_errmsg(-1));

         continue;

       }

       if (strcmp(section_name, kTextSectionName) == 0) {

         text_section = &shdr;

         break;

       }

     }

   }

   if (text_section != NULL && text_section->sh_size > 0) {

     *text_start = (char *)elf_base + text_section->sh_offset;

     *text_size = text_section->sh_size;

     return true;

   }

   return false;

 }

 FileID::FileID(const char *path) {

   strcpy(path_, path);

 }

 class AutoCloser {

  public:

   AutoCloser(int fd) : fd_(fd) {}

   ~AutoCloser() { if (fd_) close(fd_); }

  private:

   int fd_;

 };

 bool FileID::ElfFileIdentifier(unsigned char identifier[16]) {

   int fd = 0;

   if ((fd = open(path_, O_RDONLY)) < 0)

     return false;

   AutoCloser autocloser(fd);

   struct stat st;

   if (fstat(fd, &st) != 0 || st.st_size <= 0)

     return false;

   void *base = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);

   if (base == MAP_FAILED)

     return false;

   bool success = false;

   const void *text_section = NULL;

   int text_size = 0;

   if (FindElfTextSection(fd, base, &text_section, &text_size)) {

     MD5Context md5;

     MD5Init(&md5);

     MD5Update(&md5, (const unsigned char *)text_section, text_size);

     MD5Final(identifier, &md5);

     success = true;

   }

   munmap((char *)base, st.st_size);

   return success;

 }

 // static

 bool FileID::ConvertIdentifierToString(const unsigned char identifier[16],

                                        char *buffer, int buffer_length) {

   if (buffer_length < 34)

     return false;

   int buffer_idx = 0;

   for (int idx = 0; idx < 16; ++idx) {

     int hi = (identifier[idx] >> 4) & 0x0F;

     int lo = (identifier[idx]) & 0x0F;

     buffer[buffer_idx++] = (hi >= 10) ? 'A' + hi - 10 : '0' + hi;

     buffer[buffer_idx++] = (lo >= 10) ? 'A' + lo - 10 : '0' + lo;

   }

   // Add an extra "0" by the end.

   buffer[buffer_idx++] = '0';

   // NULL terminate

   buffer[buffer_idx] = 0;

   return true;

 }

 }  // namespace google_breakpad