+/* patcyh - you should pronounce it like patch
+ * Copyright (C) 2015 Jay Freeman (saurik)
+*/
+
+/* GNU General Public License, Version 3 {{{ */
+/*
+ * Cydia is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation, either version 3 of the License,
+ * or (at your option) any later version.
+ *
+ * Cydia is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Cydia. If not, see <http://www.gnu.org/licenses/>.
+**/
+/* }}} */
+
+#ifndef PATCH_HPP
+#define PATCH_HPP
+
+#include <dlfcn.h>
+
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <mach-o/loader.h>
+
+#define INSTALLD "/usr/libexec/installd"
+#define LIBUICACHE "/usr/lib/libpatcyh.dylib"
+
+static void *(*$memmem)(const void *, size_t, const void *, size_t) = reinterpret_cast<void *(*)(const void *, size_t, const void *, size_t)>(dlsym(RTLD_DEFAULT, "memmem"));
+
+template <typename Header>
+static bool PatchInstall(bool uninstall, void *data) {
+ Header *header(reinterpret_cast<Header *>(data));
+
+ load_command *command(reinterpret_cast<load_command *>(header + 1));
+ for (size_t i(0); i != header->ncmds; ++i, command = reinterpret_cast<load_command *>(reinterpret_cast<uint8_t *>(command) + command->cmdsize)) {
+ if (command->cmdsize > sizeof(Header) + header->sizeofcmds - (reinterpret_cast<uint8_t *>(command) - reinterpret_cast<uint8_t *>(header))) {
+ fprintf(stderr, "load command is to long to fit in header\n");
+ return false;
+ }
+
+ if (command->cmd != LC_LOAD_DYLIB)
+ continue;
+
+ dylib_command *load(reinterpret_cast<dylib_command *>(command));
+ const char *name(reinterpret_cast<char *>(command) + load->dylib.name.offset);
+ if (strcmp(name, LIBUICACHE) != 0)
+ continue;
+
+ if (!uninstall)
+ return true;
+
+ if (i != header->ncmds - 1) {
+ fprintf(stderr, "load command not in final position %zd %zd\n", i, header->ncmds);
+ return false;
+ }
+
+ if (reinterpret_cast<uint8_t *>(command) + command->cmdsize != reinterpret_cast<uint8_t *>(header + 1) + header->sizeofcmds) {
+ fprintf(stderr, "load command header size integrity fail\n");
+ return false;
+ }
+
+ --header->ncmds;
+ header->sizeofcmds -= command->cmdsize;
+ memset(command, 0, command->cmdsize);
+
+ return true;
+ }
+
+ if (reinterpret_cast<uint8_t *>(command) != reinterpret_cast<uint8_t *>(header + 1) + header->sizeofcmds) {
+ fprintf(stderr, "load command header size integrity fail\n");
+ return false;
+ }
+
+ if (uninstall)
+ return true;
+
+ dylib_command *load(reinterpret_cast<dylib_command *>(command));
+ memset(load, 0, sizeof(*load));
+ load->cmd = LC_LOAD_DYLIB;
+
+ load->cmdsize = sizeof(*load) + sizeof(LIBUICACHE);
+ load->cmdsize = (load->cmdsize + 15) / 16 * 16;
+ memset(load + 1, 0, load->cmdsize - sizeof(*load));
+
+ dylib *dylib(&load->dylib);
+ dylib->name.offset = sizeof(*load);
+ memcpy(load + 1, LIBUICACHE, sizeof(LIBUICACHE));
+
+ ++header->ncmds;
+ header->sizeofcmds += load->cmdsize;
+
+ return true;
+}
+
+static bool PatchInstall(bool uninstall, bool abort) {
+ if (!abort && system("ldid --") != 0) {
+ fprintf(stderr, "this package requires ldid to be installed\n");
+ return false;
+ }
+
+ int fd(open(INSTALLD, O_RDWR));
+ if (fd == -1)
+ return false;
+
+ struct stat stat;
+ if (fstat(fd, &stat) == -1) {
+ close(fd);
+ return false;
+ }
+
+ size_t size(stat.st_size);
+ void *data(mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0));
+ close(fd);
+ if (data == MAP_FAILED)
+ return false;
+
+ bool changed(false);
+ uint32_t magic(*reinterpret_cast<uint32_t *>(data));
+ switch (magic) {
+ case MH_MAGIC:
+ changed = PatchInstall<mach_header>(uninstall, data);
+ break;
+ case MH_MAGIC_64:
+ changed = PatchInstall<mach_header_64>(uninstall, data);
+ break;
+ default:
+ fprintf(stderr, "unknown header magic on installd: %08x\n", magic);
+ return false;
+ }
+
+ munmap(data, size);
+
+ if (changed) {
+ system("ldid -s "INSTALLD"");
+ system("cp -af "INSTALLD" "INSTALLD"_");
+ system("mv -f "INSTALLD"_ "INSTALLD"");
+ }
+
+ return true;
+}
+
+#endif//PATCH_HPP
projects / patcyh.git / commitdiff
