[PATCH 3/5] Use sysconf(_SC_PAGESIZE) to determine PAGE_SIZE

[Dan Fandrich]

This seems to be the most portable way to determine page size,
and the only portable way on systems where it is dynamic.

Signed-off-by: Dan Fandrich <dan at coneharvesters.com>
---
 libbb/appletlib.c |   17 ++++-------------
 1 files changed, 4 insertions(+), 13 deletions(-)

diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index 0dac0ba..955f680 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -34,17 +34,8 @@
 # include <malloc.h> /* for mallopt */
 #endif
 
-/* Try to pull in PAGE_SIZE */
-#ifdef __linux__
-# include <sys/user.h>
-#endif
-#ifdef __GNU__ /* Hurd */
-# include <mach/vm_param.h>
-#endif
-#ifndef PAGE_SIZE
-# define PAGE_SIZE (4*1024) /* guess */
-#endif
-
+/* Use 4096 if page size can't be otherwise determined */
+#define CURRENT_PAGE_SIZE ({long ps = sysconf(_SC_PAGESIZE); ps > 0 ? ps : 4*1024;})
 
 /* Declare <applet>_main() */
 #define PROTOTYPES
@@ -788,13 +779,13 @@ int main(int argc UNUSED_PARAM, char **argv)
 	 * to keep before releasing to the OS
 	 * Default is way too big: 256k
 	 */
-	mallopt(M_TRIM_THRESHOLD, 2 * PAGE_SIZE);
+	mallopt(M_TRIM_THRESHOLD, 2 * CURRENT_PAGE_SIZE);
 #endif
 #ifdef M_MMAP_THRESHOLD
 	/* M_MMAP_THRESHOLD is the request size threshold for using mmap()
 	 * Default is too big: 256k
 	 */
-	mallopt(M_MMAP_THRESHOLD, 8 * PAGE_SIZE - 256);
+	mallopt(M_MMAP_THRESHOLD, 8 * CURRENT_PAGE_SIZE - 256);
 #endif
 
 #if !BB_MMU
-- 
1.5.3.2