probes/lttng-probe-user.h

   1 /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
   2  *
   3  * lttng-probe-user.h
   4  *
   5  * Copyright (C) 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   6  */
   7
   8 #ifndef _LTTNG_PROBE_USER_H
   9 #define _LTTNG_PROBE_USER_H
  10
  11 #include <wrapper/uaccess.h>
  12
  13 /*
  14  * Calculate string length. Include final null terminating character if there is
  15  * one, or ends at first fault.
  16  */
  17 long lttng_strlen_user_inatomic(const char *addr);
  18
  19 /*
  20  * We use __copy_from_user_inatomic to copy userspace data after
  21  * checking with access_ok() and disabling page faults.
  22  *
  23  * Return 0 if OK, nonzero on error.
  24  */
  25 static inline
  26 unsigned long lttng_copy_from_user_check_nofault(void *dest,
  27                                                  const void __user *src,
  28                                                  unsigned long len)
  29 {
  30         unsigned long ret;
  31
  32         if (!lttng_access_ok(VERIFY_READ, src, len))
  33                 return 1;
  34         pagefault_disable();
  35         ret = __copy_from_user_inatomic(dest, src, len);
  36         pagefault_enable();
  37         return ret;
  38 }
  39
  40 #endif /* _LTTNG_PROBE_USER_H */