michael@0: // Copyright (c) 2007, Google Inc.
michael@0: // All rights reserved.
michael@0: //
michael@0: // Redistribution and use in source and binary forms, with or without
michael@0: // modification, are permitted provided that the following conditions are
michael@0: // met:
michael@0: //
michael@0: //     * Redistributions of source code must retain the above copyright
michael@0: // notice, this list of conditions and the following disclaimer.
michael@0: //     * Redistributions in binary form must reproduce the above
michael@0: // copyright notice, this list of conditions and the following disclaimer
michael@0: // in the documentation and/or other materials provided with the
michael@0: // distribution.
michael@0: //     * Neither the name of Google Inc. nor the names of its
michael@0: // contributors may be used to endorse or promote products derived from
michael@0: // this software without specific prior written permission.
michael@0: //
michael@0: // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0: // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0: // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0: // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
michael@0: // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
michael@0: // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
michael@0: // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0: // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0: // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0: // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0: // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0: 
michael@0: // file_id.cc: Return a unique identifier for a file
michael@0: //
michael@0: // See file_id.h for documentation
michael@0: //
michael@0: // Author: Alfred Peng
michael@0: 
michael@0: #include <elf.h>
michael@0: #include <fcntl.h>
michael@0: #include <gelf.h>
michael@0: #include <sys/mman.h>
michael@0: #include <sys/ksyms.h>
michael@0: #include <stdio.h>
michael@0: #include <string.h>
michael@0: #include <unistd.h>
michael@0: 
michael@0: #include <cassert>
michael@0: #include <cstdio>
michael@0: 
michael@0: #include "common/md5.h"
michael@0: #include "common/solaris/file_id.h"
michael@0: #include "common/solaris/message_output.h"
michael@0: #include "google_breakpad/common/minidump_format.h"
michael@0: 
michael@0: namespace google_breakpad {
michael@0: 
michael@0: class AutoElfEnder {
michael@0:  public:
michael@0:   AutoElfEnder(Elf *elf) : elf_(elf) {}
michael@0:   ~AutoElfEnder() { if (elf_) elf_end(elf_); }
michael@0:  private:
michael@0:   Elf *elf_;
michael@0: };
michael@0: 
michael@0: // Find the text section in elf object file.
michael@0: // Return the section start address and the size.
michael@0: static bool FindElfTextSection(int fd, const void *elf_base,
michael@0:                                const void **text_start,
michael@0:                                int *text_size) {
michael@0:   assert(text_start);
michael@0:   assert(text_size);
michael@0: 
michael@0:   *text_start = NULL;
michael@0:   *text_size = 0;
michael@0: 
michael@0:   if (elf_version(EV_CURRENT) == EV_NONE) {
michael@0:     print_message2(2, "elf_version() failed: %s\n", elf_errmsg(0));
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   GElf_Ehdr elf_header;
michael@0:   lseek(fd, 0L, 0);
michael@0:   Elf *elf = elf_begin(fd, ELF_C_READ, NULL);
michael@0:   AutoElfEnder elfEnder(elf);
michael@0: 
michael@0:   if (gelf_getehdr(elf, &elf_header) == (GElf_Ehdr *)NULL) {
michael@0:     print_message2(2, "failed to read elf header: %s\n", elf_errmsg(-1));
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   if (elf_header.e_ident[EI_MAG0] != ELFMAG0 ||
michael@0:       elf_header.e_ident[EI_MAG1] != ELFMAG1 ||
michael@0:       elf_header.e_ident[EI_MAG2] != ELFMAG2 ||
michael@0:       elf_header.e_ident[EI_MAG3] != ELFMAG3) {
michael@0:     print_message1(2, "header magic doesn't match\n");
michael@0:     return false;
michael@0:   }
michael@0: 
michael@0:   static const char kTextSectionName[] = ".text";
michael@0:   const GElf_Shdr *text_section = NULL;
michael@0:   Elf_Scn *scn = NULL;
michael@0:   GElf_Shdr shdr;
michael@0: 
michael@0:   while ((scn = elf_nextscn(elf, scn)) != NULL) {
michael@0:     if (gelf_getshdr(scn, &shdr) == (GElf_Shdr *)0) {
michael@0:       print_message2(2, "failed to read section header: %s\n", elf_errmsg(0));
michael@0:       return false;
michael@0:     }
michael@0: 
michael@0:     if (shdr.sh_type == SHT_PROGBITS) {
michael@0:       const char *section_name = elf_strptr(elf, elf_header.e_shstrndx,
michael@0:                                             shdr.sh_name);
michael@0:       if (!section_name) {
michael@0:         print_message2(2, "Section name error: %s\n", elf_errmsg(-1));
michael@0:         continue;
michael@0:       }
michael@0: 
michael@0:       if (strcmp(section_name, kTextSectionName) == 0) {
michael@0:         text_section = &shdr;
michael@0:         break;
michael@0:       }
michael@0:     }
michael@0:   }
michael@0:   if (text_section != NULL && text_section->sh_size > 0) {
michael@0:     *text_start = (char *)elf_base + text_section->sh_offset;
michael@0:     *text_size = text_section->sh_size;
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: FileID::FileID(const char *path) {
michael@0:   strcpy(path_, path);
michael@0: }
michael@0: 
michael@0: class AutoCloser {
michael@0:  public:
michael@0:   AutoCloser(int fd) : fd_(fd) {}
michael@0:   ~AutoCloser() { if (fd_) close(fd_); }
michael@0:  private:
michael@0:   int fd_;
michael@0: };
michael@0: 
michael@0: bool FileID::ElfFileIdentifier(unsigned char identifier[16]) {
michael@0:   int fd = 0;
michael@0:   if ((fd = open(path_, O_RDONLY)) < 0)
michael@0:     return false;
michael@0: 
michael@0:   AutoCloser autocloser(fd);
michael@0:   struct stat st;
michael@0:   if (fstat(fd, &st) != 0 || st.st_size <= 0)
michael@0:     return false;
michael@0: 
michael@0:   void *base = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
michael@0:   if (base == MAP_FAILED)
michael@0:     return false;
michael@0: 
michael@0:   bool success = false;
michael@0:   const void *text_section = NULL;
michael@0:   int text_size = 0;
michael@0: 
michael@0:   if (FindElfTextSection(fd, base, &text_section, &text_size)) {
michael@0:     MD5Context md5;
michael@0:     MD5Init(&md5);
michael@0:     MD5Update(&md5, (const unsigned char *)text_section, text_size);
michael@0:     MD5Final(identifier, &md5);
michael@0:     success = true;
michael@0:   }
michael@0: 
michael@0:   munmap((char *)base, st.st_size);
michael@0:   return success;
michael@0: }
michael@0: 
michael@0: // static
michael@0: bool FileID::ConvertIdentifierToString(const unsigned char identifier[16],
michael@0:                                        char *buffer, int buffer_length) {
michael@0:   if (buffer_length < 34)
michael@0:     return false;
michael@0: 
michael@0:   int buffer_idx = 0;
michael@0:   for (int idx = 0; idx < 16; ++idx) {
michael@0:     int hi = (identifier[idx] >> 4) & 0x0F;
michael@0:     int lo = (identifier[idx]) & 0x0F;
michael@0: 
michael@0:     buffer[buffer_idx++] = (hi >= 10) ? 'A' + hi - 10 : '0' + hi;
michael@0:     buffer[buffer_idx++] = (lo >= 10) ? 'A' + lo - 10 : '0' + lo;
michael@0:   }
michael@0: 
michael@0:   // Add an extra "0" by the end.
michael@0:   buffer[buffer_idx++] = '0';
michael@0: 
michael@0:   // NULL terminate
michael@0:   buffer[buffer_idx] = 0;
michael@0: 
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: }  // namespace google_breakpad