object_file.cc revision 13982:175e05a8ee6a 
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#include <vector>
44
45#include "base/cprintf.hh"
46#include "base/loader/aout_object.hh"
47#include "base/loader/dtb_object.hh"
48#include "base/loader/ecoff_object.hh"
49#include "base/loader/elf_object.hh"
50#include "base/loader/raw_object.hh"
51#include "base/loader/symtab.hh"
52#include "mem/port_proxy.hh"
53
54using namespace std;
55
56ObjectFile::ObjectFile(const string &_filename,
57                       size_t _len, uint8_t *_data,
58                       Arch _arch, OpSys _op_sys)
59    : filename(_filename), fileData(_data), len(_len),
60      arch(_arch), opSys(_op_sys), entry(0), globalPtr(0),
61      text{0, nullptr, 0}, data{0, nullptr, 0}, bss{0, nullptr, 0}
62{
63}
64
65
66ObjectFile::~ObjectFile()
67{
68    if (fileData) {
69        ::munmap((char*)fileData, len);
70        fileData = NULL;
71    }
72}
73
74
75bool
76ObjectFile::loadSection(Section *sec, PortProxy& mem_proxy, Addr addr_mask,
77                        Addr offset)
78{
79    if (sec->size != 0) {
80        Addr addr = (sec->baseAddr & addr_mask) + offset;
81        if (sec->fileImage) {
82            mem_proxy.writeBlob(addr, sec->fileImage, sec->size);
83        }
84        else {
85            // no image: must be bss
86            mem_proxy.memsetBlob(addr, 0, sec->size);
87        }
88    }
89    return true;
90}
91
92
93bool
94ObjectFile::loadSections(PortProxy& mem_proxy, Addr addr_mask, Addr offset)
95{
96    return (loadSection(&text, mem_proxy, addr_mask, offset)
97            && loadSection(&data, mem_proxy, addr_mask, offset)
98            && loadSection(&bss, mem_proxy, addr_mask, offset));
99}
100
101namespace
102{
103
104typedef std::vector<ObjectFile::Loader *> LoaderList;
105
106LoaderList &
107object_file_loaders()
108{
109    static LoaderList loaders;
110    return loaders;
111}
112
113} // anonymous namespace
114
115ObjectFile::Loader::Loader()
116{
117    object_file_loaders().emplace_back(this);
118}
119
120Process *
121ObjectFile::tryLoaders(ProcessParams *params, ObjectFile *obj_file)
122{
123    for (auto &loader: object_file_loaders()) {
124        Process *p = loader->load(params, obj_file);
125        if (p)
126            return p;
127    }
128
129    return nullptr;
130}
131
132static bool
133hasGzipMagic(int fd)
134{
135    uint8_t buf[2] = {0};
136    size_t sz = pread(fd, buf, 2, 0);
137    panic_if(sz != 2, "Couldn't read magic bytes from object file");
138    return ((buf[0] == 0x1f) && (buf[1] == 0x8b));
139}
140
141static int
142doGzipLoad(int fd)
143{
144    const size_t blk_sz = 4096;
145
146    gzFile fdz = gzdopen(fd, "rb");
147    if (!fdz) {
148        return -1;
149    }
150
151    size_t tmp_len = strlen(P_tmpdir);
152    char *tmpnam = (char*) malloc(tmp_len + 20);
153    strcpy(tmpnam, P_tmpdir);
154    strcpy(tmpnam+tmp_len, "/gem5-gz-obj-XXXXXX"); // 19 chars
155    fd = mkstemp(tmpnam); // repurposing fd variable for output
156    if (fd < 0) {
157        free(tmpnam);
158        gzclose(fdz);
159        return fd;
160    }
161
162    if (unlink(tmpnam) != 0)
163        warn("couldn't remove temporary file %s\n", tmpnam);
164
165    free(tmpnam);
166
167    auto buf = new uint8_t[blk_sz];
168    int r; // size of (r)emaining uncopied data in (buf)fer
169    while ((r = gzread(fdz, buf, blk_sz)) > 0) {
170        auto p = buf; // pointer into buffer
171        while (r > 0) {
172            auto sz = write(fd, p, r);
173            assert(sz <= r);
174            r -= sz;
175            p += sz;
176        }
177    }
178    delete[] buf;
179    gzclose(fdz);
180    if (r < 0) { // error
181        close(fd);
182        return -1;
183    }
184    assert(r == 0); // finished successfully
185    return fd; // return fd to decompressed temporary file for mmap()'ing
186}
187
188ObjectFile *
189createObjectFile(const string &fname, bool raw)
190{
191    // open the file
192    int fd = open(fname.c_str(), O_RDONLY);
193    if (fd < 0) {
194        return NULL;
195    }
196
197    // decompress GZ files
198    if (hasGzipMagic(fd)) {
199        fd = doGzipLoad(fd);
200        if (fd < 0) {
201            return NULL;
202        }
203    }
204
205    // find the length of the file by seeking to the end
206    off_t off = lseek(fd, 0, SEEK_END);
207    fatal_if(off < 0,
208             "Failed to determine size of object file %s\n", fname);
209    auto len = static_cast<size_t>(off);
210
211    // mmap the whole shebang
212    uint8_t *file_data = (uint8_t *)mmap(NULL, len, PROT_READ, MAP_SHARED,
213                                         fd, 0);
214    close(fd);
215
216    if (file_data == MAP_FAILED) {
217        return NULL;
218    }
219
220    ObjectFile *file_obj = NULL;
221
222    // figure out what we have here
223    if ((file_obj = ElfObject::tryFile(fname, len, file_data)) != NULL) {
224        return file_obj;
225    }
226
227    if ((file_obj = EcoffObject::tryFile(fname, len, file_data)) != NULL) {
228        return file_obj;
229    }
230
231    if ((file_obj = AoutObject::tryFile(fname, len, file_data)) != NULL) {
232        return file_obj;
233    }
234
235    if ((file_obj = DtbObject::tryFile(fname, len, file_data)) != NULL) {
236        return file_obj;
237    }
238
239    if (raw)
240        return RawObject::tryFile(fname, len, file_data);
241
242    // don't know what it is
243    munmap((char*)file_data, len);
244    return NULL;
245}
246