[PATCH v2 21/22] nolibc/sys: Implement `getpagesize(2)` function

Willy Tarreau
2023-01-10T07:27:53Z

From: Ammar Faizi <ammarfaizi2@gnuweeb.org>

This function returns the page size used by the running kernel. The
page size value is taken from the auxiliary vector at 'AT_PAGESZ' key.

'getpagesize(2)' is assumed as a syscall becuase the manpage placement
of this function is in entry 2 ('man 2 getpagesize') despite there is
no real 'getpagesize(2)' syscall in the Linux syscall table. Define
this function in 'sys.h'.

Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
tools/include/nolibc/sys.h | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index 47bf67668860..b5f8cd35c03b 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -19,6 +19,7 @@
#include <linux/fs.h>
#include <linux/loop.h>
#include <linux/time.h>
+#include <linux/auxvec.h>

#include "arch.h"
#include "errno.h"
@@ -499,6 +500,26 @@ pid_t gettid(void)
return sys_gettid();
}

+static unsigned long getauxval(unsigned long key);
+
+/*
+ * long getpagesize(void);
+ */
+
+static __attribute__((unused))
+long getpagesize(void)
+{
+ long ret;
+
+ ret = getauxval(AT_PAGESZ);
+ if (!ret) {
+ SET_ERRNO(ENOENT);
+ return -1;
+ }
+
+ return ret;
+}
+

/*
* int gettimeofday(struct timeval *tv, struct timezone *tz);
--
2.17.5