service_runtime/linux/nacl_host_dir.c

   1 /*
   2  * Copyright 2008, Google Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met:
   8  *
   9  *     * Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above
  12  * copyright notice, this list of conditions and the following disclaimer
  13  * in the documentation and/or other materials provided with the
  14  * distribution.
  15  *     * Neither the name of Google Inc. nor the names of its
  16  * contributors may be used to endorse or promote products derived from
  17  * this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * NaCl Service Runtime.  Directory descriptor / Handle abstraction.
  34  *
  35  * Note that we avoid using the thread-specific data / thread local
  36  * storage access to the "errno" variable, and instead use the raw
  37  * system call return interface of small negative numbers as errors.
  38  */
  39
  40 #include <stdint.h>
  41 #include <string.h>
  42 #include <sys/types.h>
  43 #include <sys/stat.h>
  44 #include <fcntl.h>
  45 #include <errno.h>
  46 #include <sys/mman.h>
  47 #include <unistd.h>
  48 #include <dirent.h>
  49 #include <linux/types.h>
  50 #include <linux/unistd.h>
  51
  52 #include "native_client/include/nacl_platform.h"
  53
  54 #include "native_client/service_runtime/nacl_config.h"
  55 #include "native_client/service_runtime/nacl_log.h"
  56 #include "native_client/service_runtime/nacl_host_desc.h"
  57 #include "native_client/service_runtime/nacl_host_dir.h"
  58 #include "native_client/service_runtime/sel_util.h"
  59 #include "native_client/service_runtime/sel_memory.h"
  60
  61 #include "native_client/service_runtime/include/sys/dirent.h"
  62 #include "native_client/service_runtime/include/sys/errno.h"
  63 #include "native_client/service_runtime/include/sys/fcntl.h"
  64 #include "native_client/service_runtime/include/sys/mman.h"
  65 #include "native_client/service_runtime/include/sys/stat.h"
  66
  67 #ifdef _syscall3
  68 _syscall3(int, getdents, uint, fd, struct dirent *, dirp, uint, count)
  69
  70 int getdents(unsigned int fd, struct dirent* dirp, unsigned int count);
  71 #else
  72 # include <sys/syscall.h>
  73 int getdents(unsigned int fd, struct dirent* dirp, unsigned int count)
  74 {
  75   return syscall(SYS_getdents, fd, dirp, count);
  76 }
  77 #endif
  78
  79 int NaClHostDirOpen(struct NaClHostDir  *d,
  80                     char                *path)
  81 {
  82   int  fd;
  83
  84   NaClLog(3, "NaClHostDirOpen(0x%08"PRIxPTR", %s)\n", (uintptr_t) d, path);
  85   if (NULL == d) {
  86     NaClLog(LOG_FATAL, "NaClHostDirOpen: 'this' is NULL\n");
  87   }
  88
  89   NaClLog(3, "NaClHostDirOpen: invoking open(%s)\n", path);
  90   fd = open(path, O_RDONLY);
  91   NaClLog(3, "NaClHostDirOpen: got DIR* %d\n", fd);
  92   if (-1 == fd) {
  93     NaClLog(LOG_ERROR,
  94             "NaClHostDirOpen: open returned -1, errno %d\n", errno);
  95     return -NaClXlateErrno(errno);
  96   }
  97   d->fd = fd;
  98   NaClLog(3, "NaClHostDirOpen: success.\n");
  99   return 0;
 100 }
 101
 102 ssize_t NaClHostDirGetdents(struct NaClHostDir  *d,
 103                             void                *buf,
 104                             size_t              len)
 105 {
 106   struct dirent           *host_direntp = (struct dirent *) buf;
 107   struct nacl_abi_dirent  *p;
 108   int                     retval;
 109   int                     i;
 110
 111   if (NULL == d) {
 112     NaClLog(LOG_FATAL, "NaClHostDirGetdents: 'this' is NULL\n");
 113   }
 114   NaClLog(3, "NaClHostDirGetdents(0x%08"PRIxPTR", %u):\n",
 115           (uintptr_t) buf, len);
 116   retval = getdents(d->fd, host_direntp, len);
 117   if (-1 == retval) {
 118     return -NaClXlateErrno(errno);
 119   } else if (0 == retval) {
 120     return 0;
 121   }
 122
 123   NaClLog(3, "NaClHostDirGetdents: returned %d\n", retval);
 124
 125   /*
 126    * Scrub inode numbers.
 127    */
 128   i = 0;
 129   while (i < retval) {
 130     p = (struct nacl_abi_dirent *) (((char *) buf) + i);
 131     /*
 132      * Make sure we're not tricked into writing outside of the buffer,
 133      * because.... (see below)
 134      */
 135     if ((((char *) &p->nacl_abi_d_ino) + sizeof(p->nacl_abi_d_ino)
 136          - (char *) buf) <= retval) {
 137       p->nacl_abi_d_ino = 0x6c43614e;
 138     }
 139     /*
 140      * ... we may pick up a user controlled/bogus value by following p
 141      * here, so i could make p point to the last byte of the buffer,
 142      * and p->* would be beyond the buffer.
 143      */
 144     i += p->nacl_abi_d_reclen;
 145   }
 146
 147   return retval;
 148 }
 149
 150 int NaClHostDirClose(struct NaClHostDir *d)
 151 {
 152   int retval;
 153
 154   if (NULL == d) {
 155     NaClLog(LOG_FATAL, "NaClHostDirClose: 'this' is NULL\n");
 156   }
 157   NaClLog(3, "NaClHostDirClose(%d)\n", d->fd);
 158   retval = close(d->fd);
 159   d->fd = -1;
 160   return (-1 == retval) ? -NaClXlateErrno(errno) : retval;
 161 }