setnsfpn.cpp

   1 /* Cydia - iPhone UIKit Front-End for Debian APT
   2  * Copyright (C) 2008-2014  Jay Freeman (saurik)
   3 */
   4
   5 /* GNU General Public License, Version 3 {{{ */
   6 /*
   7  * Cydia 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  * Cydia 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 Cydia.  If not, see <http://www.gnu.org/licenses/>.
  19 **/
  20 /* }}} */
  21
  22 #include <fcntl.h>
  23 #include <dirent.h>
  24 #include <unistd.h>
  25 #include <stdio.h>
  26 #include <errno.h>
  27 #include <string.h>
  28 #include <sys/stat.h>
  29
  30 #define _syscall(expr) ({ typeof(expr) _value; for (;;) { \
  31     _value = (expr); \
  32     if ((long) _value != -1) \
  33         break; \
  34     if (errno != EINTR) { \
  35         perror(#expr); \
  36         return -1; \
  37     } \
  38 } _value; })
  39
  40 int $getdirentries(int, char *, int, long *) __asm("_getdirentries");
  41
  42 struct $dirent {
  43     __uint32_t d_ino;
  44     __uint16_t d_reclen;
  45     __uint8_t  d_type;
  46     __uint8_t  d_namlen;
  47     char d_name[__DARWIN_MAXNAMLEN + 1];
  48 };
  49
  50 #define getdirentries $getdirentries
  51 #define dirent $dirent
  52
  53 enum Recurse {
  54     RecurseYes,
  55     RecurseNo,
  56     RecurseMaybe,
  57 };
  58
  59 struct File {
  60     int fd_;
  61
  62     File(int fd);
  63     ~File();
  64
  65     operator int() const;
  66 };
  67
  68 File::File(int fd) :
  69     fd_(fd)
  70 {
  71 }
  72
  73 File::~File() {
  74     close(fd_);
  75 }
  76
  77 File::operator int() const {
  78     return fd_;
  79 }
  80
  81 static int setnsfpn(const char *path, size_t before, Recurse recurse) {
  82     File fd(_syscall(open_dprotected_np(path, O_RDONLY | O_SYMLINK, 0, O_DP_GETRAWENCRYPTED)));
  83
  84     if (recurse == RecurseMaybe) {
  85         struct stat stat;
  86         _syscall(fstat(fd, &stat));
  87         switch (stat.st_mode & S_IFMT) {
  88             case S_IFLNK:
  89                 return 0;
  90             default:
  91                 return -1;
  92
  93             case S_IFDIR:
  94                 recurse = RecurseYes;
  95                 break;
  96             case S_IFREG:
  97                 recurse = RecurseNo;
  98                 break;
  99         }
 100     }
 101
 102     int mode(_syscall(fcntl(fd, F_GETPROTECTIONCLASS)));
 103     if (mode != -1 && mode != 4) {
 104         if (recurse == RecurseYes) {
 105             long address(0);
 106
 107             for (;;) {
 108                 char buffer[4096];
 109                 int size(_syscall(getdirentries(fd, buffer, sizeof(buffer), &address)));
 110                 if (size == 0)
 111                     break;
 112
 113                 const char *next(buffer), *stop(next + size);
 114                 while (next != stop) {
 115                     const dirent *dir(reinterpret_cast<const dirent *>(next));
 116                     const char *name(dir->d_name);
 117                     size_t after(strlen(name));
 118
 119                     if (false);
 120                     else if (after == 1 && name[0] == '.');
 121                     else if (after == 2 && name[0] == '.' && name[1] == '.');
 122                     else {
 123                         size_t both(before + 1 + after);
 124                         char sub[both + 1];
 125                         memcpy(sub, path, before);
 126                         sub[before] = '/';
 127                         memcpy(sub + before + 1, name, after);
 128                         sub[both] = '\0';
 129
 130                         switch (dir->d_type) {
 131                             case DT_LNK:
 132                                 break;
 133                             default:
 134                                 return -1;
 135
 136                             case DT_DIR:
 137                                 setnsfpn(sub, both, RecurseYes);
 138                                 break;
 139                             case DT_REG:
 140                                 setnsfpn(sub, both, RecurseNo);
 141                                 break;
 142                         }
 143                     }
 144
 145                     next += dir->d_reclen;
 146                 }
 147             }
 148         }
 149
 150         _syscall(fcntl(fd, F_SETPROTECTIONCLASS, 4));
 151     }
 152
 153     return 0;
 154 }
 155
 156 int main(int argc, const char *argv[]) {
 157     return setnsfpn(argv[1], strlen(argv[1]), RecurseMaybe);
 158 }