| /* Copyright (C) 2008-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library 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 |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <sys/times.h> |
| #include <sysdep.h> |
| |
| |
| clock_t |
| __times (struct tms *buf) |
| { |
| INTERNAL_SYSCALL_DECL (err); |
| clock_t ret = INTERNAL_SYSCALL (times, err, 1, buf); |
| if (INTERNAL_SYSCALL_ERROR_P (ret, err) |
| && __builtin_expect (INTERNAL_SYSCALL_ERRNO (ret, err) == EFAULT, 0) |
| && buf) |
| { |
| /* This might be an error or not. For architectures which have no |
| separate return value and error indicators we cannot |
| distinguish a return value of e.g. (clock_t) -14 from -EFAULT. |
| Therefore the only course of action is to dereference the user |
| -supplied structure on a return of (clock_t) -14. This will crash |
| applications which pass in an invalid non-NULL BUF pointer. |
| Note that Linux allows BUF to be NULL in which case we skip this. */ |
| #define touch(v) \ |
| do { \ |
| clock_t temp = v; \ |
| asm volatile ("" : "+r" (temp)); \ |
| v = temp; \ |
| } while (0) |
| touch (buf->tms_utime); |
| touch (buf->tms_stime); |
| touch (buf->tms_cutime); |
| touch (buf->tms_cstime); |
| |
| /* If we come here the memory is valid and the kernel did not |
| return an EFAULT error, but rather e.g. (clock_t) -14. |
| Return the value given by the kernel. */ |
| } |
| |
| /* On Linux this function never fails except with EFAULT. |
| POSIX says that returning a value (clock_t) -1 indicates an error, |
| but on Linux this is simply one of the valid clock values after |
| clock_t wraps. Therefore when we would return (clock_t) -1, we |
| instead return (clock_t) 0, and loose a tick of accuracy (having |
| returned 0 for two consecutive calls even though the clock |
| advanced). */ |
| if (ret == (clock_t) -1) |
| return (clock_t) 0; |
| |
| return ret; |
| } |
| weak_alias (__times, times) |
