LCOV - app.info - build/unix/elfhack/elfhack.cpp

LCOV - code coverage report
| Current view: | directory - build/unix/elfhack - elfhack.cpp (source / functions) |  | Found | Hit | Coverage |
| Test: | app.info | Lines: | 277 | 210 | 75.8 %
| Date: | 2012-04-07 | Functions: | 40 | 24 | 60.0 %

           1                 : /* ***** BEGIN LICENSE BLOCK *****
           2                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
           3                 :  *
           4                 :  * The contents of this file are subject to the Mozilla Public License Version
           5                 :  * 1.1 (the "License"); you may not use this file except in compliance with
           6                 :  * the License. You may obtain a copy of the License at
           7                 :  * http://www.mozilla.org/MPL/
           8                 :  *
           9                 :  * Software distributed under the License is distributed on an "AS IS" basis,
          10                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
          11                 :  * for the specific language governing rights and limitations under the
          12                 :  * License.
          13                 :  *
          14                 :  * The Original Code is elfhack.
          15                 :  *
          16                 :  * The Initial Developer of the Original Code is
          17                 :  * Mozilla Foundation.
          18                 :  * Portions created by the Initial Developer are Copyright (C) 2010
          19                 :  * the Initial Developer. All Rights Reserved.
          20                 :  *
          21                 :  * Contributor(s):
          22                 :  *   Mike Hommey <mh@glandium.org>
          23                 :  *
          24                 :  * Alternatively, the contents of this file may be used under the terms of
          25                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
          26                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
          27                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
          28                 :  * of those above. If you wish to allow use of your version of this file only
          29                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
          30                 :  * use your version of this file under the terms of the MPL, indicate your
          31                 :  * decision by deleting the provisions above and replace them with the notice
          32                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
          33                 :  * the provisions above, a recipient may use your version of this file under
          34                 :  * the terms of any one of the MPL, the GPL or the LGPL.
          35                 :  *
          36                 :  * ***** END LICENSE BLOCK ***** */
          37                 :
          38                 : #undef NDEBUG
          39                 : #include <assert.h>
          40                 : #include <cstring>
          41                 : #include <cstdlib>
          42                 : #include <cstdio>
          43                 : #include "elfxx.h"
          44                 :
          45                 : #define ver "0"
          46                 : #define elfhack_data ".elfhack.data.v" ver
          47                 : #define elfhack_text ".elfhack.text.v" ver
          48                 :
          49                 : #ifndef R_ARM_V4BX
          50                 : #define R_ARM_V4BX 0x28
          51                 : #endif
          52                 : #ifndef R_ARM_THM_JUMP24
          53                 : #define R_ARM_THM_JUMP24 0x1e
          54                 : #endif
          55                 :
          56                 : char *rundir = NULL;
          57                 :
          58                 : template <typename T>
          59               0 : struct wrapped {
          60                 :     T value;
          61                 : };
          62                 :
          63                 : class Elf_Addr_Traits {
          64                 : public:
          65                 :     typedef wrapped<Elf32_Addr> Type32;
          66                 :     typedef wrapped<Elf64_Addr> Type64;
          67                 :
          68                 :     template <class endian, typename R, typename T>
          69               0 :     static inline void swap(T &t, R &r) {
          70               0 :         r.value = endian::swap(t.value);
          71               0 :     }
          72                 : };
          73                 :
          74                 : class Elf_RelHack_Traits {
          75                 : public:
          76                 :     typedef Elf32_Rel Type32;
          77                 :     typedef Elf32_Rel Type64;
          78                 :
          79                 :     template <class endian, typename R, typename T>
          80           36334 :     static inline void swap(T &t, R &r) {
          81           36334 :         r.r_offset = endian::swap(t.r_offset);
          82           36334 :         r.r_info = endian::swap(t.r_info);
          83           36334 :     }
          84                 : };
          85                 :
          86                 : typedef serializable<Elf_RelHack_Traits> Elf_RelHack;
          87                 :
          88              42 : class ElfRelHack_Section: public ElfSection {
          89                 : public:
          90              21 :     ElfRelHack_Section(Elf_Shdr &s)
          91              21 :     : ElfSection(s, NULL, NULL)
          92                 :     {
          93              21 :         name = elfhack_data;
          94              21 :     };
          95                 :
          96               4 :     void serialize(std::ofstream &file, char ei_class, char ei_data)
          97                 :     {
          98           72676 :         for (std::vector<Elf_RelHack>::iterator i = rels.begin();
          99           36338 :              i != rels.end(); ++i)
         100           36334 :             (*i).serialize(file, ei_class, ei_data);
         101               4 :     }
         102                 :
         103              79 :     bool isRelocatable() {
         104              79 :         return true;
         105                 :     }
         106                 :
         107           42637 :     void push_back(Elf_RelHack &r) {
         108           42637 :         rels.push_back(r);
         109           42637 :         shdr.sh_size = rels.size() * shdr.sh_entsize;
         110           42637 :     }
         111                 : private:
         112                 :     std::vector<Elf_RelHack> rels;
         113                 : };
         114                 :
         115                 : class ElfRelHackCode_Section: public ElfSection {
         116                 : public:
         117              21 :     ElfRelHackCode_Section(Elf_Shdr &s, Elf &e)
         118              21 :     : ElfSection(s, NULL, NULL), parent(e) {
         119              42 :         std::string file(rundir);
         120              21 :         init = parent.getDynSection()->getSectionForType(DT_INIT);
         121              21 :         file += "/inject/";
         122              21 :         switch (parent.getMachine()) {
         123                 :         case EM_386:
         124              21 :             file += "x86";
         125              21 :             break;
         126                 :         case EM_X86_64:
         127               0 :             file += "x86_64";
         128               0 :             break;
         129                 :         case EM_ARM:
         130               0 :             file += "arm";
         131               0 :             break;
         132                 :         default:
         133               0 :             throw std::runtime_error("unsupported architecture");
         134                 :         }
         135              21 :         if (init == NULL)
         136               0 :             file += "-noinit";
         137              21 :         file += ".o";
         138              42 :         std::ifstream inject(file.c_str(), std::ios::in|std::ios::binary);
         139              21 :         elf = new Elf(inject);
         140              21 :         if (elf->getType() != ET_REL)
         141               0 :             throw std::runtime_error("object for injected code is not ET_REL");
         142              21 :         if (elf->getMachine() != parent.getMachine())
         143               0 :             throw std::runtime_error("architecture of object for injected code doesn't match");
         144                 :
         145              21 :         ElfSymtab_Section *symtab = NULL;
         146                 :
         147                 :         // Get all executable sections from the injected code object.
         148                 :         // Most of the time, there will only be one for the init function,
         149                 :         // but on e.g. x86, there is a separate section for
         150                 :         // __i686.get_pc_thunk.$reg
         151                 :         // Find the symbol table at the same time.
         152             273 :         for (ElfSection *section = elf->getSection(1); section != NULL;
         153             252 :              section = section->getNext()) {
         154             357 :             if ((section->getType() == SHT_PROGBITS) &&
         155             105 :                 (section->getFlags() & SHF_EXECINSTR)) {
         156              42 :                 code.push_back(section);
         157                 :                 // We need to align this section depending on the greater
         158                 :                 // alignment required by code sections.
         159              42 :                 if (shdr.sh_addralign < section->getAddrAlign())
         160              21 :                     shdr.sh_addralign = section->getAddrAlign();
         161             210 :             } else if (section->getType() == SHT_SYMTAB) {
         162              21 :                 symtab = (ElfSymtab_Section *) section;
         163                 :             }
         164                 :         }
         165              21 :         assert(code.size() != 0);
         166              21 :         if (symtab == NULL)
         167               0 :             throw std::runtime_error("Couldn't find a symbol table for the injected code");
         168                 :
         169                 :         // Find the init symbol
         170              21 :         entry_point = -1;
         171              21 :         int shndx = 0;
         172              21 :         Elf_SymValue *sym = symtab->lookup("init");
         173              21 :         if (sym) {
         174              21 :             entry_point = sym->value.getValue();
         175              21 :             shndx = sym->value.getSection()->getIndex();
         176                 :         } else
         177               0 :             throw std::runtime_error("Couldn't find an 'init' symbol in the injected code");
         178                 :
         179                 :         // Adjust code sections offsets according to their size
         180              21 :         std::vector<ElfSection *>::iterator c = code.begin();
         181              21 :         (*c)->getShdr().sh_addr = 0;
         182              42 :         for(ElfSection *last = *(c++); c != code.end(); c++) {
         183              21 :             unsigned int addr = last->getShdr().sh_addr + last->getSize();
         184              21 :             if (addr & ((*c)->getAddrAlign() - 1))
         185               0 :                 addr = (addr | ((*c)->getAddrAlign() - 1)) + 1;
         186              21 :             (*c)->getShdr().sh_addr = addr;
         187                 :         }
         188              21 :         shdr.sh_size = code.back()->getAddr() + code.back()->getSize();
         189              21 :         data = new char[shdr.sh_size];
         190              21 :         char *buf = data;
         191              63 :         for (c = code.begin(); c != code.end(); c++) {
         192              42 :             memcpy(buf, (*c)->getData(), (*c)->getSize());
         193              42 :             buf += (*c)->getSize();
         194              42 :             if ((*c)->getIndex() < shndx)
         195               0 :                 entry_point += (*c)->getSize();
         196                 :         }
         197              21 :         name = elfhack_text;
         198              21 :     }
         199                 :
         200              63 :     ~ElfRelHackCode_Section() {
         201              21 :         delete elf;
         202              42 :     }
         203                 :
         204               4 :     void serialize(std::ofstream &file, char ei_class, char ei_data)
         205                 :     {
         206                 :         // Readjust code offsets
         207              12 :         for (std::vector<ElfSection *>::iterator c = code.begin(); c != code.end(); c++)
         208               8 :             (*c)->getShdr().sh_addr += getAddr();
         209                 :
         210                 :         // Apply relocations
         211              52 :         for (ElfSection *rel = elf->getSection(1); rel != NULL; rel = rel->getNext())
         212              48 :             if ((rel->getType() == SHT_REL) || (rel->getType() == SHT_RELA)) {
         213               4 :                 ElfSection *section = rel->getInfo().section;
         214               4 :                 if ((section->getType() == SHT_PROGBITS) && (section->getFlags() & SHF_EXECINSTR)) {
         215               4 :                     if (rel->getType() == SHT_REL)
         216               4 :                         apply_relocations((ElfRel_Section<Elf_Rel> *)rel, section);
         217                 :                     else
         218               0 :                         apply_relocations((ElfRel_Section<Elf_Rela> *)rel, section);
         219                 :                 }
         220                 :             }
         221                 :
         222               4 :         ElfSection::serialize(file, ei_class, ei_data);
         223               4 :     }
         224                 :
         225              79 :     bool isRelocatable() {
         226              79 :         return true;
         227                 :     }
         228                 :
         229              21 :     unsigned int getEntryPoint() {
         230              21 :         return entry_point;
         231                 :     }
         232                 : private:
         233                 :     class pc32_relocation {
         234                 :     public:
         235              12 :         Elf32_Addr operator()(unsigned int base_addr, Elf32_Off offset,
         236                 :                               Elf32_Word addend, unsigned int addr)
         237                 :         {
         238              12 :             return addr + addend - offset - base_addr;
         239                 :         }
         240                 :     };
         241                 :
         242                 :     class arm_plt32_relocation {
         243                 :     public:
         244               0 :         Elf32_Addr operator()(unsigned int base_addr, Elf32_Off offset,
         245                 :                               Elf32_Word addend, unsigned int addr)
         246                 :         {
         247                 :             // We don't care about sign_extend because the only case where this is
         248                 :             // going to be used only jumps forward.
         249               0 :             Elf32_Addr tmp = (Elf32_Addr) (addr - offset - base_addr) >> 2;
         250               0 :             tmp = (addend + tmp) & 0x00ffffff;
         251               0 :             return (addend & 0xff000000) | tmp;
         252                 :         }
         253                 :     };
         254                 :
         255                 :     class arm_thm_jump24_relocation {
         256                 :     public:
         257               0 :         Elf32_Addr operator()(unsigned int base_addr, Elf32_Off offset,
         258                 :                               Elf32_Word addend, unsigned int addr)
         259                 :         {
         260                 :             /* Follows description of b.w instructions as per
         261                 :                ARM Architecture Reference Manual ARM® v7-A and ARM® v7-R edition, A8.6.16
         262                 :                We limit ourselves to Encoding T3.
         263                 :                We don't care about sign_extend because the only case where this is
         264                 :                going to be used only jumps forward. */
         265               0 :             Elf32_Addr tmp = (Elf32_Addr) (addr - offset - base_addr);
         266               0 :             unsigned int word0 = addend & 0xffff,
         267               0 :                          word1 = addend >> 16;
         268                 :
         269               0 :             if (((word0 & 0xf800) != 0xf000) || ((word1 & 0xd000) != 0x9000))
         270               0 :                 throw std::runtime_error("R_ARM_THM_JUMP24 relocation only supported for B.W <label>");
         271                 :
         272               0 :             unsigned int s = (word0 & (1 << 10)) >> 10;
         273               0 :             unsigned int j1 = (word1 & (1 << 13)) >> 13;
         274               0 :             unsigned int j2 = (word1 & (1 << 11)) >> 11;
         275               0 :             unsigned int i1 = j1 ^ s ? 0 : 1;
         276               0 :             unsigned int i2 = j2 ^ s ? 0 : 1;
         277                 :
         278               0 :             tmp += ((s << 24) | (i1 << 23) | (i2 << 22) | ((word0 & 0x3ff) << 12) | ((word1 & 0x7ff) << 1));
         279                 :
         280               0 :             s = (tmp & (1 << 24)) >> 24;
         281               0 :             j1 = ((tmp & (1 << 23)) >> 23) ^ !s;
         282               0 :             j2 = ((tmp & (1 << 22)) >> 22) ^ !s;
         283                 :
         284                 :             return 0xf000 | (s << 10) | ((tmp & (0x3ff << 12)) >> 12) |
         285               0 :                    (0x9000 << 16) | (j1 << 29) | (j2 << 27) | ((tmp & 0xffe) << 15);
         286                 :         }
         287                 :     };
         288                 :
         289                 :     class gotoff_relocation {
         290                 :     public:
         291              12 :         Elf32_Addr operator()(unsigned int base_addr, Elf32_Off offset,
         292                 :                               Elf32_Word addend, unsigned int addr)
         293                 :         {
         294              12 :             return addr + addend;
         295                 :         }
         296                 :     };
         297                 :
         298                 :     template <class relocation_type>
         299              24 :     void apply_relocation(ElfSection *the_code, char *base, Elf_Rel *r, unsigned int addr)
         300                 :     {
         301                 :         relocation_type relocation;
         302                 :         Elf32_Addr value;
         303              24 :         memcpy(&value, base + r->r_offset, 4);
         304              24 :         value = relocation(the_code->getAddr(), r->r_offset, value, addr);
         305              24 :         memcpy(base + r->r_offset, &value, 4);
         306              24 :     }
         307                 :
         308                 :     template <class relocation_type>
         309               0 :     void apply_relocation(ElfSection *the_code, char *base, Elf_Rela *r, unsigned int addr)
         310                 :     {
         311                 :         relocation_type relocation;
         312               0 :         Elf32_Addr value = relocation(the_code->getAddr(), r->r_offset, r->r_addend, addr);
         313               0 :         memcpy(base + r->r_offset, &value, 4);
         314               0 :     }
         315                 :
         316                 :     template <typename Rel_Type>
         317               4 :     void apply_relocations(ElfRel_Section<Rel_Type> *rel, ElfSection *the_code)
         318                 :     {
         319               4 :         assert(rel->getType() == Rel_Type::sh_type);
         320               4 :         char *buf = data + (the_code->getAddr() - code.front()->getAddr());
         321                 :         // TODO: various checks on the sections
         322               4 :         ElfSymtab_Section *symtab = (ElfSymtab_Section *)rel->getLink();
         323              28 :         for (typename std::vector<Rel_Type>::iterator r = rel->rels.begin(); r != rel->rels.end(); r++) {
         324                 :             // TODO: various checks on the symbol
         325              24 :             const char *name = symtab->syms[ELF32_R_SYM(r->r_info)].name;
         326                 :             unsigned int addr;
         327              24 :             if (symtab->syms[ELF32_R_SYM(r->r_info)].value.getSection() == NULL) {
         328              20 :                 if (strcmp(name, "relhack") == 0) {
         329               8 :                     addr = getNext()->getAddr();
         330              12 :                 } else if (strcmp(name, "elf_header") == 0) {
         331                 :                     // TODO: change this ungly hack to something better
         332               4 :                     ElfSection *ehdr = parent.getSection(1)->getPrevious()->getPrevious();
         333               4 :                     addr = ehdr->getAddr();
         334               8 :                 } else if (strcmp(name, "original_init") == 0) {
         335               4 :                     addr = init->getAddr();
         336               4 :                 } else if (strcmp(name, "_GLOBAL_OFFSET_TABLE_") == 0) {
         337                 :                     // We actually don't need a GOT, but need it as a reference for
         338                 :                     // GOTOFF relocations. We'll just use the start of the ELF file
         339               4 :                     addr = 0;
         340               0 :                 } else if (strcmp(name, "") == 0) {
         341                 :                     // This is for R_ARM_V4BX, until we find something better
         342               0 :                     addr = -1;
         343                 :                 } else {
         344               0 :                     throw std::runtime_error("Unsupported symbol in relocation");
         345                 :                 }
         346                 :             } else {
         347               4 :                 ElfSection *section = symtab->syms[ELF32_R_SYM(r->r_info)].value.getSection();
         348               4 :                 assert((section->getType() == SHT_PROGBITS) && (section->getFlags() & SHF_EXECINSTR));
         349               4 :                 addr = symtab->syms[ELF32_R_SYM(r->r_info)].value.getValue();
         350                 :             }
         351                 :             // Do the relocation
         352                 : #define REL(machine, type) (EM_ ## machine | (R_ ## machine ## _ ## type << 8))
         353              24 :             switch (elf->getMachine() | (ELF32_R_TYPE(r->r_info) << 8)) {
         354                 :             case REL(X86_64, PC32):
         355                 :             case REL(386, PC32):
         356                 :             case REL(386, GOTPC):
         357                 :             case REL(ARM, GOTPC):
         358                 :             case REL(ARM, REL32):
         359              12 :                 apply_relocation<pc32_relocation>(the_code, buf, &*r, addr);
         360              12 :                 break;
         361                 :             case REL(ARM, PLT32):
         362               0 :                 apply_relocation<arm_plt32_relocation>(the_code, buf, &*r, addr);
         363               0 :                 break;
         364                 :             case REL(ARM, THM_JUMP24):
         365               0 :                 apply_relocation<arm_thm_jump24_relocation>(the_code, buf, &*r, addr);
         366               0 :                 break;
         367                 :             case REL(386, GOTOFF):
         368                 :             case REL(ARM, GOTOFF):
         369              12 :                 apply_relocation<gotoff_relocation>(the_code, buf, &*r, addr);
         370              12 :                 break;
         371                 :             case REL(ARM, V4BX):
         372                 :                 // Ignore R_ARM_V4BX relocations
         373               0 :                 break;
         374                 :             default:
         375               0 :                 throw std::runtime_error("Unsupported relocation type");
         376                 :             }
         377                 :         }
         378               4 :     }
         379                 :
         380                 :     Elf *elf, &parent;
         381                 :     std::vector<ElfSection *> code;
         382                 :     ElfSection *init;
         383                 :     int entry_point;
         384                 : };
         385                 :
         386                 : template <typename Rel_Type>
         387              21 : int do_relocation_section(Elf *elf, unsigned int rel_type, unsigned int rel_type2)
         388                 : {
         389              21 :     ElfDynamic_Section *dyn = elf->getDynSection();
         390              21 :     if (dyn ==NULL) {
         391               0 :         fprintf(stderr, "Couldn't find SHT_DYNAMIC section\n");
         392               0 :         return -1;
         393                 :     }
         394                 :
         395              21 :     ElfSegment *relro = elf->getSegmentByType(PT_GNU_RELRO);
         396                 :
         397              21 :     ElfRel_Section<Rel_Type> *section = (ElfRel_Section<Rel_Type> *)dyn->getSectionForType(Rel_Type::d_tag);
         398              21 :     assert(section->getType() == Rel_Type::sh_type);
         399                 :
         400                 :     Elf32_Shdr relhack32_section =
         401                 :         { 0, SHT_PROGBITS, SHF_ALLOC, 0, (Elf32_Off)-1, 0, SHN_UNDEF, 0,
         402              21 :           Elf_RelHack::size(elf->getClass()), Elf_RelHack::size(elf->getClass()) }; // TODO: sh_addralign should be an alignment, not size
         403                 :     Elf32_Shdr relhackcode32_section =
         404                 :         { 0, SHT_PROGBITS, SHF_ALLOC | SHF_EXECINSTR, 0, (Elf32_Off)-1, 0,
         405              21 :           SHN_UNDEF, 0, 1, 0 };
         406              21 :     Elf_Shdr relhack_section(relhack32_section);
         407              21 :     Elf_Shdr relhackcode_section(relhackcode32_section);
         408              21 :     ElfRelHack_Section *relhack = new ElfRelHack_Section(relhack_section);
         409              21 :     ElfRelHackCode_Section *relhackcode = new ElfRelHackCode_Section(relhackcode_section, *elf);
         410                 :
         411              21 :     ElfSymtab_Section *symtab = (ElfSymtab_Section *) section->getLink();
         412              21 :     Elf_SymValue *sym = symtab->lookup("__cxa_pure_virtual");
         413                 :
         414              42 :     std::vector<Rel_Type> new_rels;
         415              21 :     Elf_RelHack relhack_entry;
         416              21 :     relhack_entry.r_offset = relhack_entry.r_info = 0;
         417              21 :     int entry_sz = (elf->getClass() == ELFCLASS32) ? 4 : 8;
         418          321489 :     for (typename std::vector<Rel_Type>::iterator i = section->rels.begin();
         419                 :          i != section->rels.end(); i++) {
         420                 :         // We don't need to keep R_*_NONE relocations
         421          321468 :         if (!ELF32_R_TYPE(i->r_info))
         422               0 :             continue;
         423          321468 :         ElfSection *section = elf->getSectionAt(i->r_offset);
         424                 :         // __cxa_pure_virtual is a function used in vtables to point at pure
         425                 :         // virtual methods. The __cxa_pure_virtual function usually abort()s.
         426                 :         // These functions are however normally never called. In the case
         427                 :         // where they would, jumping to the NULL address instead of calling
         428                 :         // __cxa_pure_virtual is going to work just as well. So we can remove
         429                 :         // relocations for the __cxa_pure_virtual symbol and NULL out the
         430                 :         // content at the offset pointed by the relocation.
         431          321468 :         if (sym) {
         432          309846 :             if (sym->defined) {
         433                 :                 // If we are statically linked to libstdc++, the
         434                 :                 // __cxa_pure_virtual symbol is defined in our lib, and we
         435                 :                 // have relative relocations (rel_type) for it.
         436               0 :                 if (ELF32_R_TYPE(i->r_info) == rel_type) {
         437               0 :                     serializable<Elf_Addr_Traits> addr(&section->getData()[i->r_offset - section->getAddr()], entry_sz, elf->getClass(), elf->getData());
         438               0 :                     if (addr.value == sym->value.getValue()) {
         439               0 :                         memset((char *)&section->getData()[i->r_offset - section->getAddr()], 0, entry_sz);
         440               0 :                         continue;
         441                 :                     }
         442                 :                 }
         443                 :             } else {
         444                 :                 // If we are dynamically linked to libstdc++, the
         445                 :                 // __cxa_pure_virtual symbol is undefined in our lib, and we
         446                 :                 // have absolute relocations (rel_type2) for it.
         447          309846 :                 if ((ELF32_R_TYPE(i->r_info) == rel_type2) &&
         448                 :                     (sym == &symtab->syms[ELF32_R_SYM(i->r_info)])) {
         449           34510 :                     memset((char *)&section->getData()[i->r_offset - section->getAddr()], 0, entry_sz);
         450           34510 :                     continue;
         451                 :                 }
         452                 :             }
         453                 :         }
         454                 :         // Don't pack relocations happening in non writable sections.
         455                 :         // Our injected code is likely not to be allowed to write there.
         456          286958 :         if (!(section->getFlags() & SHF_WRITE) || (ELF32_R_TYPE(i->r_info) != rel_type) ||
         457                 :             (relro && (i->r_offset >= relro->getAddr()) &&
         458                 :                       (i->r_offset < relro->getAddr() + relro->getMemSize())))
         459            3059 :             new_rels.push_back(*i);
         460                 :         else {
         461                 :             // TODO: check that i->r_addend == *i->r_offset
         462          283899 :             if (i->r_offset == relhack_entry.r_offset + relhack_entry.r_info * entry_sz) {
         463          241283 :                 relhack_entry.r_info++;
         464                 :             } else {
         465           42616 :                 if (relhack_entry.r_offset)
         466           42595 :                     relhack->push_back(relhack_entry);
         467           42616 :                 relhack_entry.r_offset = i->r_offset;
         468           42616 :                 relhack_entry.r_info = 1;
         469                 :             }
         470                 :         }
         471                 :     }
         472              21 :     if (relhack_entry.r_offset)
         473              21 :         relhack->push_back(relhack_entry);
         474                 :     // Last entry must be NULL
         475              21 :     relhack_entry.r_offset = relhack_entry.r_info = 0;
         476              21 :     relhack->push_back(relhack_entry);
         477                 :
         478              21 :     relhackcode->insertAfter(section);
         479              21 :     relhack->insertAfter(relhackcode);
         480                 :
         481              21 :     unsigned int old_end = section->getOffset() + section->getSize();
         482              21 :     section->rels.assign(new_rels.begin(), new_rels.end());
         483              21 :     section->shrink(new_rels.size() * section->getEntSize());
         484              21 :     ElfLocation *init = new ElfLocation(relhackcode, relhackcode->getEntryPoint());
         485              21 :     dyn->setValueForType(DT_INIT, init);
         486                 :     // TODO: adjust the value according to the remaining number of relative relocations
         487              21 :     if (dyn->getValueForType(Rel_Type::d_tag_count))
         488              21 :         dyn->setValueForType(Rel_Type::d_tag_count, new ElfPlainValue(0));
         489                 :
         490              21 :     if (relhack->getOffset() + relhack->getSize() >= old_end) {
         491               3 :         fprintf(stderr, "No gain. Skipping\n");
         492               3 :         return -1;
         493                 :     }
         494              18 :     return 0;
         495                 : }
         496                 :
         497               1 : static inline int backup_file(const char *name)
         498                 : {
         499               2 :     std::string fname(name);
         500               1 :     fname += ".bak";
         501               1 :     return rename(name, fname.c_str());
         502                 : }
         503                 :
         504              21 : void do_file(const char *name, bool backup = false, bool force = false)
         505                 : {
         506              42 :     std::ifstream file(name, std::ios::in|std::ios::binary);
         507              21 :     Elf *elf = new Elf(file);
         508              21 :     unsigned int size = elf->getSize();
         509              21 :     fprintf(stderr, "%s: ", name);
         510              21 :     if (elf->getType() != ET_DYN) {
         511               0 :         fprintf(stderr, "Not a shared object. Skipping\n");
         512               0 :         delete elf;
         513                 :         return;
         514                 :     }
         515                 :
         516             797 :     for (ElfSection *section = elf->getSection(1); section != NULL;
         517                 :          section = section->getNext()) {
         518            1531 :         if (section->getName() &&
         519             755 :             (strncmp(section->getName(), ".elfhack.", 9) == 0)) {
         520               0 :             fprintf(stderr, "Already elfhacked. Skipping\n");
         521               0 :             delete elf;
         522                 :             return;
         523                 :         }
         524                 :     }
         525                 :
         526              21 :     int exit = -1;
         527              21 :     switch (elf->getMachine()) {
         528                 :     case EM_386:
         529              21 :         exit = do_relocation_section<Elf_Rel>(elf, R_386_RELATIVE, R_386_32);
         530              21 :         break;
         531                 :     case EM_X86_64:
         532               0 :         exit = do_relocation_section<Elf_Rela>(elf, R_X86_64_RELATIVE, R_X86_64_64);
         533               0 :         break;
         534                 :     case EM_ARM:
         535               0 :         exit = do_relocation_section<Elf_Rel>(elf, R_ARM_RELATIVE, R_ARM_ABS32);
         536               0 :         break;
         537                 :     }
         538              21 :     if (exit == 0) {
         539              18 :         if (!force && (elf->getSize() >= size)) {
         540              14 :             fprintf(stderr, "No gain. Skipping\n");
         541               4 :         } else if (backup && backup_file(name) != 0) {
         542               0 :             fprintf(stderr, "Couln't create backup file\n");
         543                 :         } else {
         544               8 :             std::ofstream ofile(name, std::ios::out|std::ios::binary|std::ios::trunc);
         545               4 :             elf->write(ofile);
         546               4 :             fprintf(stderr, "Reduced by %d bytes\n", size - elf->getSize());
         547                 :         }
         548                 :     }
         549              21 :     delete elf;
         550                 : }
         551                 :
         552               2 : int main(int argc, char *argv[])
         553                 : {
         554                 :     int arg;
         555               2 :     bool backup = false;
         556               2 :     bool force = false;
         557               2 :     char *lastSlash = rindex(argv[0], '/');
         558               2 :     if (lastSlash != NULL)
         559               2 :         rundir = strndup(argv[0], lastSlash - argv[0]);
         560              25 :     for (arg = 1; arg < argc; arg++) {
         561              23 :         if (strcmp(argv[arg], "-f") == 0)
         562               1 :             force = true;
         563              22 :         else if (strcmp(argv[arg], "-b") == 0)
         564               1 :             backup = true;
         565                 :         else
         566              21 :             do_file(argv[arg], backup, force);
         567                 :     }
         568                 :
         569               2 :     free(rundir);
         570               2 :     return 0;
         571               6 : }

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