diff options
Diffstat (limited to 'REORG.TODO/sysdeps/unix/sysv/linux/times.c')
| -rw-r--r-- | REORG.TODO/sysdeps/unix/sysv/linux/times.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/unix/sysv/linux/times.c b/REORG.TODO/sysdeps/unix/sysv/linux/times.c new file mode 100644 index 0000000000..63c8bf8ff0 --- /dev/null +++ b/REORG.TODO/sysdeps/unix/sysv/linux/times.c @@ -0,0 +1,67 @@ +/* Copyright (C) 2008-2017 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) |