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64ca3f32 RM |
1 | /* Determine whether the host has multiple processors. Linux version. |
2 | Copyright (C) 1996, 2002 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Library General Public License as | |
7 | published by the Free Software Foundation; either version 2 of the | |
8 | License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Library General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Library General Public | |
16 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
17 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
18 | Boston, MA 02111-1307, USA. */ | |
19 | ||
20 | #include <sys/sysctl.h> | |
21 | ||
22 | /* Test whether the machine has more than one processor. This is not the | |
23 | best test but good enough. More complicated tests would require `malloc' | |
24 | which is not available at that time. */ | |
25 | static inline int | |
26 | is_smp_system (void) | |
27 | { | |
28 | static const int sysctl_args[] = { CTL_KERN, KERN_VERSION }; | |
29 | char buf[512]; | |
30 | size_t reslen = sizeof (buf); | |
31 | ||
32 | /* Try reading the number using `sysctl' first. */ | |
33 | if (__sysctl ((int *) sysctl_args, | |
34 | sizeof (sysctl_args) / sizeof (sysctl_args[0]), | |
35 | buf, &reslen, NULL, 0) < 0) | |
36 | { | |
37 | /* This was not successful. Now try reading the /proc filesystem. */ | |
38 | int fd = __open ("/proc/sys/kernel/version", O_RDONLY); | |
39 | if (__builtin_expect (fd, 0) == -1 | |
40 | || (reslen = __read (fd, buf, sizeof (buf))) <= 0) | |
41 | /* This also didn't work. We give up and say it's a UP machine. */ | |
42 | buf[0] = '\0'; | |
43 | ||
44 | __close (fd); | |
45 | } | |
46 | ||
47 | return strstr (buf, "SMP") != NULL; | |
48 | } |