object_file.cc revision 11793 
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 * Authors: Nathan Binkert
29 *          Steve Reinhardt
30 */
31
32#include "base/loader/object_file.hh"
33
34#include <fcntl.h>
35#include <sys/mman.h>
36#include <sys/types.h>
37#include <unistd.h>
38#include <zlib.h>
39
40#include <cstdio>
41#include <list>
42#include <string>
43
44#include "base/cprintf.hh"
45#include "base/loader/aout_object.hh"
46#include "base/loader/dtb_object.hh"
47#include "base/loader/ecoff_object.hh"
48#include "base/loader/elf_object.hh"
49#include "base/loader/raw_object.hh"
50#include "base/loader/symtab.hh"
51#include "mem/port_proxy.hh"
52
53using namespace std;
54
55ObjectFile::ObjectFile(const string &_filename,
56                       size_t _len, uint8_t *_data,
57                       Arch _arch, OpSys _op_sys)
58    : filename(_filename), fileData(_data), len(_len),
59      arch(_arch), opSys(_op_sys), entry(0), globalPtr(0),
60      text{0, nullptr, 0}, data{0, nullptr, 0}, bss{0, nullptr, 0}
61{
62}
63
64
65ObjectFile::~ObjectFile()
66{
67    if (fileData) {
68        ::munmap((char*)fileData, len);
69        fileData = NULL;
70    }
71}
72
73
74bool
75ObjectFile::loadSection(Section *sec, PortProxy& mem_proxy, Addr addr_mask,
76                        Addr offset)
77{
78    if (sec->size != 0) {
79        Addr addr = (sec->baseAddr & addr_mask) + offset;
80        if (sec->fileImage) {
81            mem_proxy.writeBlob(addr, sec->fileImage, sec->size);
82        }
83        else {
84            // no image: must be bss
85            mem_proxy.memsetBlob(addr, 0, sec->size);
86        }
87    }
88    return true;
89}
90
91
92bool
93ObjectFile::loadSections(PortProxy& mem_proxy, Addr addr_mask, Addr offset)
94{
95    return (loadSection(&text, mem_proxy, addr_mask, offset)
96            && loadSection(&data, mem_proxy, addr_mask, offset)
97            && loadSection(&bss, mem_proxy, addr_mask, offset));
98}
99
100static bool
101hasGzipMagic(int fd)
102{
103    uint8_t buf[2] = {0};
104    size_t sz = pread(fd, buf, 2, 0);
105    panic_if(sz != 2, "Couldn't read magic bytes from object file");
106    return ((buf[0] == 0x1f) && (buf[1] == 0x8b));
107}
108
109static int
110doGzipLoad(int fd)
111{
112    const size_t blk_sz = 4096;
113
114    gzFile fdz = gzdopen(fd, "rb");
115    if (!fdz) {
116        return -1;
117    }
118
119    size_t tmp_len = strlen(P_tmpdir);
120    char *tmpnam = (char*) malloc(tmp_len + 20);
121    strcpy(tmpnam, P_tmpdir);
122    strcpy(tmpnam+tmp_len, "/gem5-gz-obj-XXXXXX"); // 19 chars
123    fd = mkstemp(tmpnam); // repurposing fd variable for output
124    if (fd < 0) {
125        free(tmpnam);
126        gzclose(fdz);
127        return fd;
128    }
129
130    if (unlink(tmpnam) != 0)
131        warn("couldn't remove temporary file %s\n", tmpnam);
132
133    free(tmpnam);
134
135    auto buf = new uint8_t[blk_sz];
136    int r; // size of (r)emaining uncopied data in (buf)fer
137    while ((r = gzread(fdz, buf, blk_sz)) > 0) {
138        auto p = buf; // pointer into buffer
139        while (r > 0) {
140            auto sz = write(fd, p, r);
141            assert(sz <= r);
142            r -= sz;
143            p += sz;
144        }
145    }
146    delete[] buf;
147    gzclose(fdz);
148    if (r < 0) { // error
149        close(fd);
150        return -1;
151    }
152    assert(r == 0); // finished successfully
153    return fd; // return fd to decompressed temporary file for mmap()'ing
154}
155
156ObjectFile *
157createObjectFile(const string &fname, bool raw)
158{
159    // open the file
160    int fd = open(fname.c_str(), O_RDONLY);
161    if (fd < 0) {
162        return NULL;
163    }
164
165    // decompress GZ files
166    if (hasGzipMagic(fd)) {
167        fd = doGzipLoad(fd);
168        if (fd < 0) {
169            return NULL;
170        }
171    }
172
173    // find the length of the file by seeking to the end
174    off_t off = lseek(fd, 0, SEEK_END);
175    fatal_if(off < 0,
176             "Failed to determine size of object file %s\n", fname);
177    auto len = static_cast<size_t>(off);
178
179    // mmap the whole shebang
180    uint8_t *file_data = (uint8_t *)mmap(NULL, len, PROT_READ, MAP_SHARED,
181                                         fd, 0);
182    close(fd);
183
184    if (file_data == MAP_FAILED) {
185        return NULL;
186    }
187
188    ObjectFile *file_obj = NULL;
189
190    // figure out what we have here
191    if ((file_obj = ElfObject::tryFile(fname, len, file_data)) != NULL) {
192        return file_obj;
193    }
194
195    if ((file_obj = EcoffObject::tryFile(fname, len, file_data)) != NULL) {
196        return file_obj;
197    }
198
199    if ((file_obj = AoutObject::tryFile(fname, len, file_data)) != NULL) {
200        return file_obj;
201    }
202
203    if ((file_obj = DtbObject::tryFile(fname, len, file_data)) != NULL) {
204        return file_obj;
205    }
206
207    if (raw)
208        return RawObject::tryFile(fname, len, file_data);
209
210    // don't know what it is
211    munmap((char*)file_data, len);
212    return NULL;
213}
214