1/*
2 * Copyright (c) 2003-2005 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: Steve Reinhardt
29 * Ali Saidi
30 */
31
32#include <cassert>
33#include <string>
34
35#include "gelf.h"
36
37#include "base/loader/elf_object.hh"
38#include "base/loader/symtab.hh"
39#include "base/misc.hh"
40#include "base/trace.hh" // for DPRINTF
41#include "sim/byteswap.hh"
42
43using namespace std;
44
45ObjectFile *
46ElfObject::tryFile(const string &fname, int fd, size_t len, uint8_t *data)
47{
48 Elf *elf;
49 GElf_Ehdr ehdr;
50 Arch arch = UnknownArch;
51 OpSys opSys = UnknownOpSys;
52
53 // check that header matches library version
54 if (elf_version(EV_CURRENT) == EV_NONE)
55 panic("wrong elf version number!");
56
57 // get a pointer to elf structure
58 elf = elf_memory((char*)data,len);
59 // will only fail if fd is invalid
60 assert(elf != NULL);
61
62 // Check that we actually have a elf file
63 if (gelf_getehdr(elf, &ehdr) ==0) {
64 DPRINTFR(Loader, "Not ELF\n");
65 elf_end(elf);
66 return NULL;
67 } else {
68 //Detect the architecture
69 //Since we don't know how to check for alpha right now, we'll
70 //just assume if it wasn't something else and it's 64 bit, that's
71 //what it must be.
72 if (ehdr.e_machine == EM_SPARC64 ||
73 (ehdr.e_machine == EM_SPARC &&
74 ehdr.e_ident[EI_CLASS] == ELFCLASS64)||
75 ehdr.e_machine == EM_SPARCV9) {
76 arch = ObjectFile::SPARC64;
77 } else if (ehdr.e_machine == EM_SPARC32PLUS ||
78 (ehdr.e_machine == EM_SPARC &&
79 ehdr.e_ident[EI_CLASS] == ELFCLASS32)) {
80 arch = ObjectFile::SPARC32;
81 } else if (ehdr.e_machine == EM_MIPS
82 && ehdr.e_ident[EI_CLASS] == ELFCLASS32) {
83 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB) {
84 arch = ObjectFile::Mips;
85 } else {
86 fatal("The binary you're trying to load is compiled for big "
87 "endian MIPS. M5\nonly supports little endian MIPS. "
88 "Please recompile your binary.\n");
89 }
90 } else if (ehdr.e_machine == EM_X86_64 &&
91 ehdr.e_ident[EI_CLASS] == ELFCLASS64) {
92 arch = ObjectFile::X86_64;
93 } else if (ehdr.e_machine == EM_386 &&
94 ehdr.e_ident[EI_CLASS] == ELFCLASS32) {
95 arch = ObjectFile::I386;
96 } else if (ehdr.e_ident[EI_CLASS] == ELFCLASS64) {
97 arch = ObjectFile::Alpha;
98 } else if (ehdr.e_machine == EM_ARM) {
99 arch = ObjectFile::Arm;
100 } else {
101 warn("Unknown architecture: %d\n", ehdr.e_machine);
102 arch = ObjectFile::UnknownArch;
103 }
104
105 //Detect the operating system
106 switch (ehdr.e_ident[EI_OSABI])
107 {
108
109 case ELFOSABI_LINUX:
| 1/*
2 * Copyright (c) 2003-2005 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: Steve Reinhardt
29 * Ali Saidi
30 */
31
32#include <cassert>
33#include <string>
34
35#include "gelf.h"
36
37#include "base/loader/elf_object.hh"
38#include "base/loader/symtab.hh"
39#include "base/misc.hh"
40#include "base/trace.hh" // for DPRINTF
41#include "sim/byteswap.hh"
42
43using namespace std;
44
45ObjectFile *
46ElfObject::tryFile(const string &fname, int fd, size_t len, uint8_t *data)
47{
48 Elf *elf;
49 GElf_Ehdr ehdr;
50 Arch arch = UnknownArch;
51 OpSys opSys = UnknownOpSys;
52
53 // check that header matches library version
54 if (elf_version(EV_CURRENT) == EV_NONE)
55 panic("wrong elf version number!");
56
57 // get a pointer to elf structure
58 elf = elf_memory((char*)data,len);
59 // will only fail if fd is invalid
60 assert(elf != NULL);
61
62 // Check that we actually have a elf file
63 if (gelf_getehdr(elf, &ehdr) ==0) {
64 DPRINTFR(Loader, "Not ELF\n");
65 elf_end(elf);
66 return NULL;
67 } else {
68 //Detect the architecture
69 //Since we don't know how to check for alpha right now, we'll
70 //just assume if it wasn't something else and it's 64 bit, that's
71 //what it must be.
72 if (ehdr.e_machine == EM_SPARC64 ||
73 (ehdr.e_machine == EM_SPARC &&
74 ehdr.e_ident[EI_CLASS] == ELFCLASS64)||
75 ehdr.e_machine == EM_SPARCV9) {
76 arch = ObjectFile::SPARC64;
77 } else if (ehdr.e_machine == EM_SPARC32PLUS ||
78 (ehdr.e_machine == EM_SPARC &&
79 ehdr.e_ident[EI_CLASS] == ELFCLASS32)) {
80 arch = ObjectFile::SPARC32;
81 } else if (ehdr.e_machine == EM_MIPS
82 && ehdr.e_ident[EI_CLASS] == ELFCLASS32) {
83 if (ehdr.e_ident[EI_DATA] == ELFDATA2LSB) {
84 arch = ObjectFile::Mips;
85 } else {
86 fatal("The binary you're trying to load is compiled for big "
87 "endian MIPS. M5\nonly supports little endian MIPS. "
88 "Please recompile your binary.\n");
89 }
90 } else if (ehdr.e_machine == EM_X86_64 &&
91 ehdr.e_ident[EI_CLASS] == ELFCLASS64) {
92 arch = ObjectFile::X86_64;
93 } else if (ehdr.e_machine == EM_386 &&
94 ehdr.e_ident[EI_CLASS] == ELFCLASS32) {
95 arch = ObjectFile::I386;
96 } else if (ehdr.e_ident[EI_CLASS] == ELFCLASS64) {
97 arch = ObjectFile::Alpha;
98 } else if (ehdr.e_machine == EM_ARM) {
99 arch = ObjectFile::Arm;
100 } else {
101 warn("Unknown architecture: %d\n", ehdr.e_machine);
102 arch = ObjectFile::UnknownArch;
103 }
104
105 //Detect the operating system
106 switch (ehdr.e_ident[EI_OSABI])
107 {
108
109 case ELFOSABI_LINUX:
|
119 default:
120 opSys = ObjectFile::UnknownOpSys;
121 }
122
123 //take a look at the .note.ABI section
124 //It can let us know what's what.
125 if (opSys == ObjectFile::UnknownOpSys) {
126 Elf_Scn *section;
127 GElf_Shdr shdr;
128 Elf_Data *data;
129 uint32_t osAbi;;
130 int secIdx = 1;
131
132 // Get the first section
133 section = elf_getscn(elf, secIdx);
134
135 // While there are no more sections
136 while (section != NULL && opSys == ObjectFile::UnknownOpSys) {
137 gelf_getshdr(section, &shdr);
138 if (shdr.sh_type == SHT_NOTE && !strcmp(".note.ABI-tag",
139 elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name))) {
140 // we have found a ABI note section
141 // Check the 5th 32bit word for OS 0 == linux, 1 == hurd,
142 // 2 == solaris, 3 == freebsd
143 data = elf_rawdata(section, NULL);
144 assert(data->d_buf);
145 if(ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
146 osAbi = htole(((uint32_t*)data->d_buf)[4]);
147 else
148 osAbi = htobe(((uint32_t*)data->d_buf)[4]);
149
150 switch(osAbi) {
151 case 0:
152 opSys = ObjectFile::Linux;
153 break;
154 case 2:
155 opSys = ObjectFile::Solaris;
156 break;
157 }
158 } // if section found
159 if (!strcmp(".SUNW_version", elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name)))
160 opSys = ObjectFile::Solaris;
161 if (!strcmp(".stab.index", elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name)))
162 opSys = ObjectFile::Solaris;
163
164 section = elf_getscn(elf, ++secIdx);
165 } // while sections
166 }
167
168 ElfObject * result = new ElfObject(fname, fd, len, data, arch, opSys);
169
170 //The number of headers in the file
171 result->_programHeaderCount = ehdr.e_phnum;
172 //Record the size of each entry
173 result->_programHeaderSize = ehdr.e_phentsize;
174 if(result->_programHeaderCount) //If there is a program header table
175 {
176 //Figure out the virtual address of the header table in the
177 //final memory image. We use the program headers themselves
178 //to translate from a file offset to the address in the image.
179 GElf_Phdr phdr;
180 uint64_t e_phoff = ehdr.e_phoff;
181 result->_programHeaderTable = 0;
182 for(int hdrnum = 0; hdrnum < result->_programHeaderCount; hdrnum++)
183 {
184 gelf_getphdr(elf, hdrnum, &phdr);
185 //Check if we've found the segment with the headers in it
186 if(phdr.p_offset <= e_phoff &&
187 phdr.p_offset + phdr.p_filesz > e_phoff)
188 {
189 result->_programHeaderTable = phdr.p_paddr + e_phoff;
190 break;
191 }
192 }
193 }
194 else
195 result->_programHeaderTable = 0;
196
197
198 elf_end(elf);
199 return result;
200 }
201}
202
203
204ElfObject::ElfObject(const string &_filename, int _fd,
205 size_t _len, uint8_t *_data,
206 Arch _arch, OpSys _opSys)
207 : ObjectFile(_filename, _fd, _len, _data, _arch, _opSys)
208
209{
210 Elf *elf;
211 GElf_Ehdr ehdr;
212
213 // check that header matches library version
214 if (elf_version(EV_CURRENT) == EV_NONE)
215 panic("wrong elf version number!");
216
217 // get a pointer to elf structure
218 elf = elf_memory((char*)fileData,len);
219 // will only fail if fd is invalid
220 assert(elf != NULL);
221
222 // Check that we actually have a elf file
223 if (gelf_getehdr(elf, &ehdr) ==0) {
224 panic("Not ELF, shouldn't be here");
225 }
226
227 entry = ehdr.e_entry;
228
229 // initialize segment sizes to 0 in case they're not present
230 text.size = data.size = bss.size = 0;
231
232 int secIdx = 1;
233 Elf_Scn *section;
234 GElf_Shdr shdr;
235
236 // The first address of some important sections.
237 Addr textSecStart = 0;
238 Addr dataSecStart = 0;
239 Addr bssSecStart = 0;
240
241 // Get the first section
242 section = elf_getscn(elf, secIdx);
243
244 // Find the beginning of the most interesting sections.
245 while (section != NULL) {
246 gelf_getshdr(section, &shdr);
247 char * secName = elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name);
248
249 if (!strcmp(".text", secName)) {
250 textSecStart = shdr.sh_addr;
251 } else if (!strcmp(".data", secName)) {
252 dataSecStart = shdr.sh_addr;
253 } else if (!strcmp(".bss", secName)) {
254 bssSecStart = shdr.sh_addr;
255 }
256
257 section = elf_getscn(elf, ++secIdx);
258 }
259
260 // Go through all the segments in the program, record them, and scrape
261 // out information about the text, data, and bss areas needed by other
262 // code.
263 for (int i = 0; i < ehdr.e_phnum; ++i) {
264 GElf_Phdr phdr;
265 if (gelf_getphdr(elf, i, &phdr) == 0) {
266 panic("gelf_getphdr failed for segment %d.", i);
267 }
268
269 // for now we don't care about non-loadable segments
270 if (!(phdr.p_type & PT_LOAD))
271 continue;
272
273 // Check to see if this segment contains the bss section.
274 if (phdr.p_paddr <= bssSecStart &&
275 phdr.p_paddr + phdr.p_memsz > bssSecStart &&
276 phdr.p_memsz - phdr.p_filesz > 0) {
277 bss.baseAddr = phdr.p_paddr + phdr.p_filesz;
278 bss.size = phdr.p_memsz - phdr.p_filesz;
279 bss.fileImage = NULL;
280 }
281
282 // Check to see if this is the text or data segment
283 if (phdr.p_vaddr <= textSecStart &&
284 phdr.p_vaddr + phdr.p_filesz > textSecStart) {
285 text.baseAddr = phdr.p_paddr;
286 text.size = phdr.p_filesz;
287 text.fileImage = fileData + phdr.p_offset;
288 } else if (phdr.p_vaddr <= dataSecStart &&
289 phdr.p_vaddr + phdr.p_filesz > dataSecStart) {
290 data.baseAddr = phdr.p_paddr;
291 data.size = phdr.p_filesz;
292 data.fileImage = fileData + phdr.p_offset;
293 } else {
294 // If it's none of the above but is loadable,
295 // load the filesize worth of data
296 Segment extra;
297 extra.baseAddr = phdr.p_paddr;
298 extra.size = phdr.p_filesz;
299 extra.fileImage = fileData + phdr.p_offset;
300 extraSegments.push_back(extra);
301 }
302 }
303
304 // should have found at least one loadable segment
305 assert(text.size != 0);
306
307 DPRINTFR(Loader, "text: 0x%x %d\ndata: 0x%x %d\nbss: 0x%x %d\n",
308 text.baseAddr, text.size, data.baseAddr, data.size,
309 bss.baseAddr, bss.size);
310
311 elf_end(elf);
312
313 // We will actually read the sections when we need to load them
314}
315
316
317bool
318ElfObject::loadSomeSymbols(SymbolTable *symtab, int binding)
319{
320 Elf *elf;
321 int sec_idx = 1; // there is a 0 but it is nothing, go figure
322 Elf_Scn *section;
323 GElf_Shdr shdr;
324 Elf_Data *data;
325 int count, ii;
326 bool found = false;
327 GElf_Sym sym;
328
329 if (!symtab)
330 return false;
331
332 // check that header matches library version
333 if (elf_version(EV_CURRENT) == EV_NONE)
334 panic("wrong elf version number!");
335
336 // get a pointer to elf structure
337 elf = elf_memory((char*)fileData,len);
338
339 assert(elf != NULL);
340
341 // Get the first section
342 section = elf_getscn(elf, sec_idx);
343
344 // While there are no more sections
345 while (section != NULL) {
346 gelf_getshdr(section, &shdr);
347
348 if (shdr.sh_type == SHT_SYMTAB) {
349 found = true;
350 data = elf_getdata(section, NULL);
351 count = shdr.sh_size / shdr.sh_entsize;
352 DPRINTF(Loader, "Found Symbol Table, %d symbols present\n", count);
353
354 // loop through all the symbols, only loading global ones
355 for (ii = 0; ii < count; ++ii) {
356 gelf_getsym(data, ii, &sym);
357 if (GELF_ST_BIND(sym.st_info) == binding) {
358 symtab->insert(sym.st_value,
359 elf_strptr(elf, shdr.sh_link, sym.st_name));
360 }
361 }
362 }
363 ++sec_idx;
364 section = elf_getscn(elf, sec_idx);
365 }
366
367 elf_end(elf);
368
369 return found;
370}
371
372bool
373ElfObject::loadGlobalSymbols(SymbolTable *symtab, Addr addrMask)
374{
375 return loadSomeSymbols(symtab, STB_GLOBAL);
376}
377
378bool
379ElfObject::loadLocalSymbols(SymbolTable *symtab, Addr addrMask)
380{
381 return loadSomeSymbols(symtab, STB_LOCAL);
382}
383
384bool
385ElfObject::loadSections(Port *memPort, Addr addrMask)
386{
387 if (!ObjectFile::loadSections(memPort, addrMask))
388 return false;
389
390 vector<Segment>::iterator extraIt;
391 for (extraIt = extraSegments.begin();
392 extraIt != extraSegments.end(); extraIt++) {
393 if (!loadSection(&(*extraIt), memPort, addrMask)) {
394 return false;
395 }
396 }
397 return true;
398}
399
400void
401ElfObject::getSections()
402{
403 Elf *elf;
404 int sec_idx = 1; // there is a 0 but it is nothing, go figure
405 Elf_Scn *section;
406 GElf_Shdr shdr;
407
408 GElf_Ehdr ehdr;
409
410 assert(!sectionNames.size());
411
412 // check that header matches library version
413 if (elf_version(EV_CURRENT) == EV_NONE)
414 panic("wrong elf version number!");
415
416 // get a pointer to elf structure
417 elf = elf_memory((char*)fileData,len);
418 assert(elf != NULL);
419
420 // Check that we actually have a elf file
421 if (gelf_getehdr(elf, &ehdr) ==0) {
422 panic("Not ELF, shouldn't be here");
423 }
424
425 // Get the first section
426 section = elf_getscn(elf, sec_idx);
427
428 // While there are no more sections
429 while (section != NULL) {
430 gelf_getshdr(section, &shdr);
431 sectionNames.insert(elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name));
432 section = elf_getscn(elf, ++sec_idx);
433 } // while sections
434}
435
436bool
437ElfObject::sectionExists(string sec)
438{
439 if (!sectionNames.size())
440 getSections();
441 return sectionNames.find(sec) != sectionNames.end();
442}
443
444
| 121 default:
122 opSys = ObjectFile::UnknownOpSys;
123 }
124
125 //take a look at the .note.ABI section
126 //It can let us know what's what.
127 if (opSys == ObjectFile::UnknownOpSys) {
128 Elf_Scn *section;
129 GElf_Shdr shdr;
130 Elf_Data *data;
131 uint32_t osAbi;;
132 int secIdx = 1;
133
134 // Get the first section
135 section = elf_getscn(elf, secIdx);
136
137 // While there are no more sections
138 while (section != NULL && opSys == ObjectFile::UnknownOpSys) {
139 gelf_getshdr(section, &shdr);
140 if (shdr.sh_type == SHT_NOTE && !strcmp(".note.ABI-tag",
141 elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name))) {
142 // we have found a ABI note section
143 // Check the 5th 32bit word for OS 0 == linux, 1 == hurd,
144 // 2 == solaris, 3 == freebsd
145 data = elf_rawdata(section, NULL);
146 assert(data->d_buf);
147 if(ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
148 osAbi = htole(((uint32_t*)data->d_buf)[4]);
149 else
150 osAbi = htobe(((uint32_t*)data->d_buf)[4]);
151
152 switch(osAbi) {
153 case 0:
154 opSys = ObjectFile::Linux;
155 break;
156 case 2:
157 opSys = ObjectFile::Solaris;
158 break;
159 }
160 } // if section found
161 if (!strcmp(".SUNW_version", elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name)))
162 opSys = ObjectFile::Solaris;
163 if (!strcmp(".stab.index", elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name)))
164 opSys = ObjectFile::Solaris;
165
166 section = elf_getscn(elf, ++secIdx);
167 } // while sections
168 }
169
170 ElfObject * result = new ElfObject(fname, fd, len, data, arch, opSys);
171
172 //The number of headers in the file
173 result->_programHeaderCount = ehdr.e_phnum;
174 //Record the size of each entry
175 result->_programHeaderSize = ehdr.e_phentsize;
176 if(result->_programHeaderCount) //If there is a program header table
177 {
178 //Figure out the virtual address of the header table in the
179 //final memory image. We use the program headers themselves
180 //to translate from a file offset to the address in the image.
181 GElf_Phdr phdr;
182 uint64_t e_phoff = ehdr.e_phoff;
183 result->_programHeaderTable = 0;
184 for(int hdrnum = 0; hdrnum < result->_programHeaderCount; hdrnum++)
185 {
186 gelf_getphdr(elf, hdrnum, &phdr);
187 //Check if we've found the segment with the headers in it
188 if(phdr.p_offset <= e_phoff &&
189 phdr.p_offset + phdr.p_filesz > e_phoff)
190 {
191 result->_programHeaderTable = phdr.p_paddr + e_phoff;
192 break;
193 }
194 }
195 }
196 else
197 result->_programHeaderTable = 0;
198
199
200 elf_end(elf);
201 return result;
202 }
203}
204
205
206ElfObject::ElfObject(const string &_filename, int _fd,
207 size_t _len, uint8_t *_data,
208 Arch _arch, OpSys _opSys)
209 : ObjectFile(_filename, _fd, _len, _data, _arch, _opSys)
210
211{
212 Elf *elf;
213 GElf_Ehdr ehdr;
214
215 // check that header matches library version
216 if (elf_version(EV_CURRENT) == EV_NONE)
217 panic("wrong elf version number!");
218
219 // get a pointer to elf structure
220 elf = elf_memory((char*)fileData,len);
221 // will only fail if fd is invalid
222 assert(elf != NULL);
223
224 // Check that we actually have a elf file
225 if (gelf_getehdr(elf, &ehdr) ==0) {
226 panic("Not ELF, shouldn't be here");
227 }
228
229 entry = ehdr.e_entry;
230
231 // initialize segment sizes to 0 in case they're not present
232 text.size = data.size = bss.size = 0;
233
234 int secIdx = 1;
235 Elf_Scn *section;
236 GElf_Shdr shdr;
237
238 // The first address of some important sections.
239 Addr textSecStart = 0;
240 Addr dataSecStart = 0;
241 Addr bssSecStart = 0;
242
243 // Get the first section
244 section = elf_getscn(elf, secIdx);
245
246 // Find the beginning of the most interesting sections.
247 while (section != NULL) {
248 gelf_getshdr(section, &shdr);
249 char * secName = elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name);
250
251 if (!strcmp(".text", secName)) {
252 textSecStart = shdr.sh_addr;
253 } else if (!strcmp(".data", secName)) {
254 dataSecStart = shdr.sh_addr;
255 } else if (!strcmp(".bss", secName)) {
256 bssSecStart = shdr.sh_addr;
257 }
258
259 section = elf_getscn(elf, ++secIdx);
260 }
261
262 // Go through all the segments in the program, record them, and scrape
263 // out information about the text, data, and bss areas needed by other
264 // code.
265 for (int i = 0; i < ehdr.e_phnum; ++i) {
266 GElf_Phdr phdr;
267 if (gelf_getphdr(elf, i, &phdr) == 0) {
268 panic("gelf_getphdr failed for segment %d.", i);
269 }
270
271 // for now we don't care about non-loadable segments
272 if (!(phdr.p_type & PT_LOAD))
273 continue;
274
275 // Check to see if this segment contains the bss section.
276 if (phdr.p_paddr <= bssSecStart &&
277 phdr.p_paddr + phdr.p_memsz > bssSecStart &&
278 phdr.p_memsz - phdr.p_filesz > 0) {
279 bss.baseAddr = phdr.p_paddr + phdr.p_filesz;
280 bss.size = phdr.p_memsz - phdr.p_filesz;
281 bss.fileImage = NULL;
282 }
283
284 // Check to see if this is the text or data segment
285 if (phdr.p_vaddr <= textSecStart &&
286 phdr.p_vaddr + phdr.p_filesz > textSecStart) {
287 text.baseAddr = phdr.p_paddr;
288 text.size = phdr.p_filesz;
289 text.fileImage = fileData + phdr.p_offset;
290 } else if (phdr.p_vaddr <= dataSecStart &&
291 phdr.p_vaddr + phdr.p_filesz > dataSecStart) {
292 data.baseAddr = phdr.p_paddr;
293 data.size = phdr.p_filesz;
294 data.fileImage = fileData + phdr.p_offset;
295 } else {
296 // If it's none of the above but is loadable,
297 // load the filesize worth of data
298 Segment extra;
299 extra.baseAddr = phdr.p_paddr;
300 extra.size = phdr.p_filesz;
301 extra.fileImage = fileData + phdr.p_offset;
302 extraSegments.push_back(extra);
303 }
304 }
305
306 // should have found at least one loadable segment
307 assert(text.size != 0);
308
309 DPRINTFR(Loader, "text: 0x%x %d\ndata: 0x%x %d\nbss: 0x%x %d\n",
310 text.baseAddr, text.size, data.baseAddr, data.size,
311 bss.baseAddr, bss.size);
312
313 elf_end(elf);
314
315 // We will actually read the sections when we need to load them
316}
317
318
319bool
320ElfObject::loadSomeSymbols(SymbolTable *symtab, int binding)
321{
322 Elf *elf;
323 int sec_idx = 1; // there is a 0 but it is nothing, go figure
324 Elf_Scn *section;
325 GElf_Shdr shdr;
326 Elf_Data *data;
327 int count, ii;
328 bool found = false;
329 GElf_Sym sym;
330
331 if (!symtab)
332 return false;
333
334 // check that header matches library version
335 if (elf_version(EV_CURRENT) == EV_NONE)
336 panic("wrong elf version number!");
337
338 // get a pointer to elf structure
339 elf = elf_memory((char*)fileData,len);
340
341 assert(elf != NULL);
342
343 // Get the first section
344 section = elf_getscn(elf, sec_idx);
345
346 // While there are no more sections
347 while (section != NULL) {
348 gelf_getshdr(section, &shdr);
349
350 if (shdr.sh_type == SHT_SYMTAB) {
351 found = true;
352 data = elf_getdata(section, NULL);
353 count = shdr.sh_size / shdr.sh_entsize;
354 DPRINTF(Loader, "Found Symbol Table, %d symbols present\n", count);
355
356 // loop through all the symbols, only loading global ones
357 for (ii = 0; ii < count; ++ii) {
358 gelf_getsym(data, ii, &sym);
359 if (GELF_ST_BIND(sym.st_info) == binding) {
360 symtab->insert(sym.st_value,
361 elf_strptr(elf, shdr.sh_link, sym.st_name));
362 }
363 }
364 }
365 ++sec_idx;
366 section = elf_getscn(elf, sec_idx);
367 }
368
369 elf_end(elf);
370
371 return found;
372}
373
374bool
375ElfObject::loadGlobalSymbols(SymbolTable *symtab, Addr addrMask)
376{
377 return loadSomeSymbols(symtab, STB_GLOBAL);
378}
379
380bool
381ElfObject::loadLocalSymbols(SymbolTable *symtab, Addr addrMask)
382{
383 return loadSomeSymbols(symtab, STB_LOCAL);
384}
385
386bool
387ElfObject::loadSections(Port *memPort, Addr addrMask)
388{
389 if (!ObjectFile::loadSections(memPort, addrMask))
390 return false;
391
392 vector<Segment>::iterator extraIt;
393 for (extraIt = extraSegments.begin();
394 extraIt != extraSegments.end(); extraIt++) {
395 if (!loadSection(&(*extraIt), memPort, addrMask)) {
396 return false;
397 }
398 }
399 return true;
400}
401
402void
403ElfObject::getSections()
404{
405 Elf *elf;
406 int sec_idx = 1; // there is a 0 but it is nothing, go figure
407 Elf_Scn *section;
408 GElf_Shdr shdr;
409
410 GElf_Ehdr ehdr;
411
412 assert(!sectionNames.size());
413
414 // check that header matches library version
415 if (elf_version(EV_CURRENT) == EV_NONE)
416 panic("wrong elf version number!");
417
418 // get a pointer to elf structure
419 elf = elf_memory((char*)fileData,len);
420 assert(elf != NULL);
421
422 // Check that we actually have a elf file
423 if (gelf_getehdr(elf, &ehdr) ==0) {
424 panic("Not ELF, shouldn't be here");
425 }
426
427 // Get the first section
428 section = elf_getscn(elf, sec_idx);
429
430 // While there are no more sections
431 while (section != NULL) {
432 gelf_getshdr(section, &shdr);
433 sectionNames.insert(elf_strptr(elf, ehdr.e_shstrndx, shdr.sh_name));
434 section = elf_getscn(elf, ++sec_idx);
435 } // while sections
436}
437
438bool
439ElfObject::sectionExists(string sec)
440{
441 if (!sectionNames.size())
442 getSections();
443 return sectionNames.find(sec) != sectionNames.end();
444}
445
446
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