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 void *Symbol(struct dyld_all_image_infos *infos, const char *library, const char *name) {
  82     const dyld_image_info *info(NULL);
  83     for (uint32_t i(0); i != infos->infoArrayCount; ++i)
  84         if ($strcmp(infos->infoArray[i].imageFilePath, library) == 0)
  85             info = &infos->infoArray[i];
  86     if (info == NULL)
  87         return NULL;
  88
  89     const mach_header_xx *mach(reinterpret_cast<const mach_header_xx *>(info->imageLoadAddress));
  90     if (mach->magic != MH_MAGIC_XX)
  91         return NULL;
  92
  93     const struct symtab_command *stp(NULL);
  94     forlc (command, mach, LC_SYMTAB, struct symtab_command)
  95         stp = command;
  96     if (stp == NULL)
  97         return NULL;
  98
  99     size_t slide(_not(size_t));
 100     const nlist_xx *symbols(NULL);
 101     const char *strings(NULL);
 102
 103     forlc (segment, mach, LC_SEGMENT_XX, segment_command_xx) {
 104         if (segment->fileoff == 0)
 105             slide = reinterpret_cast<size_t>(mach) - segment->vmaddr;
 106         if (stp->symoff >= segment->fileoff && stp->symoff < segment->fileoff + segment->filesize)
 107             symbols = reinterpret_cast<const nlist_xx *>(stp->symoff - segment->fileoff + segment->vmaddr + slide);
 108         if (stp->stroff >= segment->fileoff && stp->stroff < segment->fileoff + segment->filesize)
 109             strings = reinterpret_cast<const char *>(stp->stroff - segment->fileoff + segment->vmaddr + slide);
 110     }
 111
 112     if (slide == _not(size_t) || symbols == NULL || strings == NULL)
 113         return NULL;
 114
 115     for (size_t i(0); i != stp->nsyms; ++i) {
 116         const nlist_xx *symbol(&symbols[i]);
 117         if (symbol->n_un.n_strx == 0 || (symbol->n_type & N_STAB) != 0)
 118             continue;
 119
 120         const char *nambuf(strings + symbol->n_un.n_strx);
 121         if ($strcmp(name, nambuf) != 0)
 122             continue;
 123
 124         uintptr_t value(symbol->n_value);
 125         if (value == 0)
 126             continue;
 127
 128         value += slide;
 129         return reinterpret_cast<void *>(value);
 130     }
 131
 132     return NULL;
 133 }
 134
 135 struct Dynamic {
 136     char *(*dlerror)();
 137     void *(*dlsym)(void *, const char *);
 138 };
 139
 140 template <typename Type_>
 141 static _finline void dlset(Dynamic *dynamic, Type_ &function, const char *name, void *handle = RTLD_DEFAULT) {
 142     function = reinterpret_cast<Type_>(dynamic->dlsym(handle, name));
 143     if (function == NULL)
 144         dynamic->dlerror();
 145 }
 146
 147 template <typename Type_>
 148 static _finline void cyset(Baton *baton, Type_ &function, const char *name, const char *library) {
 149     struct dyld_all_image_infos *infos(reinterpret_cast<struct dyld_all_image_infos *>(baton->dyld));
 150     function = reinterpret_cast<Type_>(Symbol(infos, library, name));
 151 }
 152
 153 void *Routine(void *arg) {
 154     Baton *baton(reinterpret_cast<Baton *>(arg));
 155
 156     Dynamic dynamic;
 157     cyset(baton, dynamic.dlerror, "_dlerror", "/usr/lib/system/libdyld.dylib");
 158     cyset(baton, dynamic.dlsym, "_dlsym", "/usr/lib/system/libdyld.dylib");
 159
 160     int (*pthread_detach)(pthread_t);
 161     dlset(&dynamic, pthread_detach, "pthread_detach");
 162
 163     pthread_t (*pthread_self)();
 164     dlset(&dynamic, pthread_self, "pthread_self");
 165
 166     pthread_detach(pthread_self());
 167
 168     void *(*dlopen)(const char *, int);
 169     dlset(&dynamic, dlopen, "dlopen");
 170
 171     void *handle(dlopen(baton->library, RTLD_LAZY | RTLD_LOCAL));
 172     if (handle == NULL) {
 173         dynamic.dlerror();
 174         return NULL;
 175     }
 176
 177     void (*CYHandleServer)(pid_t);
 178     dlset(&dynamic, CYHandleServer, "CYHandleServer", handle);
 179     if (CYHandleServer == NULL) {
 180         dynamic.dlerror();
 181         return NULL;
 182     }
 183
 184     CYHandleServer(baton->pid);
 185     return NULL;
 186 }
 187
 188 extern "C" void Start(Baton *baton) {
 189     struct _pthread self;
 190     $bzero(&self, sizeof(self));
 191
 192     void (*$__pthread_set_self)(pthread_t);
 193     cyset(baton, $__pthread_set_self, "___pthread_set_self", "/usr/lib/system/libsystem_c.dylib");
 194
 195     self.tsd[0] = &self;
 196     $__pthread_set_self(&self);
 197
 198     int (*$pthread_create)(pthread_t *, const pthread_attr_t *, void *(*)(void *), void *);
 199     cyset(baton, $pthread_create, "_pthread_create", "/usr/lib/system/libsystem_c.dylib");
 200
 201     pthread_t thread;
 202     $pthread_create(&thread, NULL, &Routine, baton);
 203
 204     mach_port_t (*$mach_thread_self)();
 205     cyset(baton, $mach_thread_self, "_mach_thread_self", "/usr/lib/system/libsystem_kernel.dylib");
 206
 207     kern_return_t (*$thread_terminate)(thread_act_t);
 208     cyset(baton, $thread_terminate, "_thread_terminate", "/usr/lib/system/libsystem_kernel.dylib");
 209
 210     $thread_terminate($mach_thread_self());
 211 }