src/base/loader/image_file_data.cc

   1 /*
   2  * Copyright (c) 2002-2004 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include "base/loader/image_file_data.hh"
  30
  31 #include <fcntl.h>
  32 #include <sys/mman.h>
  33 #include <sys/types.h>
  34 #include <unistd.h>
  35 #include <zlib.h>
  36
  37 #include <cstdio>
  38 #include <vector>
  39
  40 #include "base/logging.hh"
  41
  42 namespace Loader
  43 {
  44
  45 static bool
  46 hasGzipMagic(int fd)
  47 {
  48     uint8_t buf[2] = {0};
  49     size_t sz = pread(fd, buf, 2, 0);
  50     panic_if(sz != 2, "Couldn't read magic bytes from object file");
  51     return ((buf[0] == 0x1f) && (buf[1] == 0x8b));
  52 }
  53
  54 static int
  55 doGzipLoad(int fd)
  56 {
  57     const size_t blk_sz = 4096;
  58
  59     gzFile fdz = gzdopen(fd, "rb");
  60     if (!fdz) {
  61         return -1;
  62     }
  63
  64     size_t tmp_len = strlen(P_tmpdir);
  65     char *tmpnam = (char*) malloc(tmp_len + 20);
  66     strcpy(tmpnam, P_tmpdir);
  67     strcpy(tmpnam+tmp_len, "/gem5-gz-obj-XXXXXX"); // 19 chars
  68     fd = mkstemp(tmpnam); // repurposing fd variable for output
  69     if (fd < 0) {
  70         free(tmpnam);
  71         gzclose(fdz);
  72         return fd;
  73     }
  74
  75     if (unlink(tmpnam) != 0)
  76         warn("couldn't remove temporary file %s\n", tmpnam);
  77
  78     free(tmpnam);
  79
  80     auto buf = new uint8_t[blk_sz];
  81     int r; // size of (r)emaining uncopied data in (buf)fer
  82     while ((r = gzread(fdz, buf, blk_sz)) > 0) {
  83         auto p = buf; // pointer into buffer
  84         while (r > 0) {
  85             auto sz = write(fd, p, r);
  86             assert(sz <= r);
  87             r -= sz;
  88             p += sz;
  89         }
  90     }
  91     delete[] buf;
  92     gzclose(fdz);
  93     if (r < 0) { // error
  94         close(fd);
  95         return -1;
  96     }
  97     assert(r == 0); // finished successfully
  98     return fd; // return fd to decompressed temporary file for mmap()'ing
  99 }
 100
 101 ImageFileData::ImageFileData(const std::string &fname)
 102 {
 103     _filename = fname;
 104
 105     // Open the file.
 106     int fd = open(fname.c_str(), O_RDONLY);
 107     panic_if(fd < 0, "Failed to open file %s.\n", fname);
 108
 109     // Decompress GZ files.
 110     if (hasGzipMagic(fd)) {
 111         fd = doGzipLoad(fd);
 112         panic_if(fd < 0, "Failed to unzip file %s.\n", fname);
 113     }
 114
 115     // Find the length of the file by seeking to the end.
 116     off_t off = lseek(fd, 0, SEEK_END);
 117     fatal_if(off < 0, "Failed to determine size of file %s.\n", fname);
 118     _len = static_cast<size_t>(off);
 119
 120     // Mmap the whole shebang.
 121     _data = (uint8_t *)mmap(NULL, _len, PROT_READ, MAP_SHARED, fd, 0);
 122     close(fd);
 123
 124     panic_if(_data == MAP_FAILED, "Failed to mmap file %s.\n", fname);
 125 }
 126
 127 ImageFileData::~ImageFileData()
 128 {
 129     munmap((void *)_data, _len);
 130 }
 131
 132 } // namespace Loader