| /* Determine whether the host has multiple processors. Linux version. |
| Copyright (C) 1996-2018 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 Library General Public License as |
| published by the Free Software Foundation; either version 2 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 |
| Library General Public License for more details. |
| |
| You should have received a copy of the GNU Library General Public |
| License along with the GNU C Library; see the file COPYING.LIB. If |
| not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <string.h> |
| #include <sys/utsname.h> |
| #include <not-cancel.h> |
| |
| /* Test whether the machine has more than one processor. This is not the |
| best test but good enough. More complicated tests would require `malloc' |
| which is not available at that time. */ |
| static inline int |
| is_smp_system (void) |
| { |
| union |
| { |
| struct utsname uts; |
| char buf[512]; |
| } u; |
| char *cp; |
| |
| /* Try reading the number using `sysctl' first. */ |
| if (__uname (&u.uts) == 0) |
| cp = u.uts.version; |
| else |
| { |
| /* This was not successful. Now try reading the /proc filesystem. */ |
| int fd = __open_nocancel ("/proc/sys/kernel/version", O_RDONLY); |
| if (__builtin_expect (fd, 0) == -1 |
| || __read_nocancel (fd, u.buf, sizeof (u.buf)) <= 0) |
| /* This also didn't work. We give up and say it's a UP machine. */ |
| u.buf[0] = '\0'; |
| |
| __close_nocancel_nostatus (fd); |
| cp = u.buf; |
| } |
| |
| return strstr (cp, "SMP") != NULL; |
| } |