Trampoline.t.cpp

   1 /* Cycript - Optimizing JavaScript Compiler/Runtime
   2  * Copyright (C) 2009-2013  Jay Freeman (saurik)
   3 */
   4
   5 /* GNU General Public License, Version 3 {{{ */
   6 /*
   7  * Cycript is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published
   9  * by the Free Software Foundation, either version 3 of the License,
  10  * or (at your option) any later version.
  11  *
  12  * Cycript is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with Cycript.  If not, see <http://www.gnu.org/licenses/>.
  19 **/
  20 /* }}} */
  21
  22 #define _PTHREAD_ATTR_T
  23 #include <pthread_internals.h>
  24
  25 #include <mach-o/dyld.h>
  26 #include <mach-o/dyld_images.h>
  27 #include <mach-o/loader.h>
  28
  29 extern "C" {
  30 #include <mach-o/nlist.h>
  31 }
  32
  33 #include "Standard.hpp"
  34 #include "Baton.hpp"
  35
  36 static void $bzero(void *data, size_t size) {
  37     char *bytes(reinterpret_cast<char *>(data));
  38     for (size_t i(0); i != size; ++i)
  39         bytes[i] = 0;
  40 }
  41
  42 static int $strcmp(const char *lhs, const char *rhs) {
  43     while (*lhs == *rhs) {
  44         if (*lhs == '\0')
  45             return 0;
  46         ++lhs, ++rhs;
  47     } return *lhs < *rhs ? -1 : 1;
  48 }
  49
  50 #ifdef __LP64__
  51 typedef struct mach_header_64 mach_header_xx;
  52 typedef struct nlist_64 nlist_xx;
  53 typedef struct segment_command_64 segment_command_xx;
  54
  55 static const uint32_t LC_SEGMENT_XX = LC_SEGMENT_64;
  56 static const uint32_t MH_MAGIC_XX = MH_MAGIC_64;
  57 #else
  58 typedef struct mach_header mach_header_xx;
  59 typedef struct nlist nlist_xx;
  60 typedef struct segment_command segment_command_xx;
  61
  62 static const uint32_t LC_SEGMENT_XX = LC_SEGMENT;
  63 static const uint32_t MH_MAGIC_XX = MH_MAGIC;
  64 #endif
  65
  66 #define forlc(command, mach, lc, type) \
  67     if (const struct load_command *load_commands = reinterpret_cast<const struct load_command *>(mach + 1)) \
  68         if (const struct load_command *lcp = load_commands) \
  69             for (uint32_t i(0); i != mach->ncmds; ++i, lcp = reinterpret_cast<const struct load_command *>(reinterpret_cast<const uint8_t *>(lcp) + lcp->cmdsize)) \
  70                 if ( \
  71                     lcp->cmdsize % sizeof(long) != 0 || lcp->cmdsize <= 0 || \
  72                     reinterpret_cast<const uint8_t *>(lcp) + lcp->cmdsize > reinterpret_cast<const uint8_t *>(load_commands) + mach->sizeofcmds \
  73                 ) \
  74                     return NULL; \
  75                 else if (lcp->cmd != lc) \
  76                     continue; \
  77                 else if (lcp->cmdsize < sizeof(type)) \
  78                     return NULL; \
  79                 else if (const type *command = reinterpret_cast<const type *>(lcp))
  80
  81 static const mach_header_xx *Library(struct dyld_all_image_infos *infos, const char *name) {
  82     for (uint32_t i(0); i != infos->infoArrayCount; ++i) {
  83         const dyld_image_info &info(infos->infoArray[i]);
  84         const mach_header_xx *mach(reinterpret_cast<const mach_header_xx *>(info.imageLoadAddress));
  85         if (mach->magic != MH_MAGIC_XX)
  86             continue;
  87
  88         const char *path(info.imageFilePath);
  89         forlc (dylib, mach, LC_ID_DYLIB, dylib_command)
  90             path = reinterpret_cast<const char *>(dylib) + dylib->dylib.name.offset;
  91         if ($strcmp(path, name) != 0)
  92             continue;
  93
  94         return mach;
  95     }
  96
  97     return NULL;
  98 }
  99
 100 static void *Symbol(const mach_header_xx *mach, const char *name) {
 101     const struct symtab_command *stp(NULL);
 102     forlc (command, mach, LC_SYMTAB, struct symtab_command)
 103         stp = command;
 104     if (stp == NULL)
 105         return NULL;
 106
 107     size_t slide(_not(size_t));
 108     const nlist_xx *symbols(NULL);
 109     const char *strings(NULL);
 110
 111     forlc (segment, mach, LC_SEGMENT_XX, segment_command_xx) {
 112         if (segment->fileoff == 0)
 113             slide = reinterpret_cast<size_t>(mach) - segment->vmaddr;
 114         if (stp->symoff >= segment->fileoff && stp->symoff < segment->fileoff + segment->filesize)
 115             symbols = reinterpret_cast<const nlist_xx *>(stp->symoff - segment->fileoff + segment->vmaddr + slide);
 116         if (stp->stroff >= segment->fileoff && stp->stroff < segment->fileoff + segment->filesize)
 117             strings = reinterpret_cast<const char *>(stp->stroff - segment->fileoff + segment->vmaddr + slide);
 118     }
 119
 120     if (slide == _not(size_t) || symbols == NULL || strings == NULL)
 121         return NULL;
 122
 123     for (size_t i(0); i != stp->nsyms; ++i) {
 124         const nlist_xx *symbol(&symbols[i]);
 125         if (symbol->n_un.n_strx == 0 || (symbol->n_type & N_STAB) != 0)
 126             continue;
 127
 128         const char *nambuf(strings + symbol->n_un.n_strx);
 129         if ($strcmp(name, nambuf) != 0)
 130             continue;
 131
 132         uintptr_t value(symbol->n_value);
 133         if (value == 0)
 134             continue;
 135
 136         value += slide;
 137         return reinterpret_cast<void *>(value);
 138     }
 139
 140     return NULL;
 141 }
 142
 143 struct Dynamic {
 144     char *(*dlerror)();
 145     void *(*dlsym)(void *, const char *);
 146 };
 147
 148 template <typename Type_>
 149 static _finline void dlset(Dynamic *dynamic, Type_ &function, const char *name, void *handle = RTLD_DEFAULT) {
 150     function = reinterpret_cast<Type_>(dynamic->dlsym(handle, name));
 151     if (function == NULL)
 152         dynamic->dlerror();
 153 }
 154
 155 template <typename Type_>
 156 static _finline void cyset(Type_ &function, const char *name, const mach_header_xx *mach) {
 157     function = reinterpret_cast<Type_>(Symbol(mach, name));
 158 }
 159
 160 static _finline const mach_header_xx *Library(Baton *baton, const char *name) {
 161     struct dyld_all_image_infos *infos(reinterpret_cast<struct dyld_all_image_infos *>(baton->dyld));
 162     return Library(infos, name);
 163 }
 164
 165 void *Routine(void *arg) {
 166     Baton *baton(reinterpret_cast<Baton *>(arg));
 167
 168     const mach_header_xx *dyld(Library(baton, "/usr/lib/system/libdyld.dylib"));
 169
 170     Dynamic dynamic;
 171     cyset(dynamic.dlerror, "_dlerror", dyld);
 172     cyset(dynamic.dlsym, "_dlsym", dyld);
 173
 174     int (*pthread_detach)(pthread_t);
 175     dlset(&dynamic, pthread_detach, "pthread_detach");
 176
 177     pthread_t (*pthread_self)();
 178     dlset(&dynamic, pthread_self, "pthread_self");
 179
 180     pthread_detach(pthread_self());
 181
 182     void *(*dlopen)(const char *, int);
 183     dlset(&dynamic, dlopen, "dlopen");
 184
 185     void *handle(dlopen(baton->library, RTLD_LAZY | RTLD_LOCAL));
 186     if (handle == NULL) {
 187         dynamic.dlerror();
 188         return NULL;
 189     }
 190
 191     void (*CYHandleServer)(pid_t);
 192     dlset(&dynamic, CYHandleServer, "CYHandleServer", handle);
 193     if (CYHandleServer == NULL) {
 194         dynamic.dlerror();
 195         return NULL;
 196     }
 197
 198     CYHandleServer(baton->pid);
 199     return NULL;
 200 }
 201
 202 extern "C" void Start(Baton *baton) {
 203     struct _pthread self;
 204     $bzero(&self, sizeof(self));
 205
 206     const mach_header_xx *pthread(Library(baton, "/usr/lib/system/libsystem_pthread.dylib"));
 207     if (pthread == NULL)
 208         pthread = Library(baton, "/usr/lib/system/libsystem_c.dylib");
 209
 210     void (*$__pthread_set_self)(pthread_t);
 211     cyset($__pthread_set_self, "___pthread_set_self", pthread);
 212
 213     self.tsd[0] = &self;
 214     $__pthread_set_self(&self);
 215
 216     int (*$pthread_create)(pthread_t *, const pthread_attr_t *, void *(*)(void *), void *);
 217     cyset($pthread_create, "_pthread_create", pthread);
 218
 219     pthread_t thread;
 220     $pthread_create(&thread, NULL, &Routine, baton);
 221
 222     const mach_header_xx *kernel(Library(baton, "/usr/lib/system/libsystem_kernel.dylib"));
 223
 224     mach_port_t (*$mach_thread_self)();
 225     cyset($mach_thread_self, "_mach_thread_self", kernel);
 226
 227     kern_return_t (*$thread_terminate)(thread_act_t);
 228     cyset($thread_terminate, "_thread_terminate", kernel);
 229
 230     $thread_terminate($mach_thread_self());
 231 }