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authorChristian Wiese <chris@opensde.org>2014-04-10 19:40:37 +0200
committerDaniel Borkmann <dborkman@redhat.com>2014-04-11 09:28:57 +0200
commit453f6eb9d79dd5aa2812ef956b22723f0a493086 (patch)
tree31ecebf6ad6a23655983538aadeab16414e30924
parent1d351ecaac125d9d7a88b2f7cde2a831a674281a (diff)
built_in: changed to not unconditionally define PAGE_SIZE
When building against musl libc I encountered following issue: --------------------------------------------------------------------------- In file included from xmalloc.h:6:0, from xmalloc.c:17: built_in.h:181:0: warning: "PAGE_SIZE" redefined [enabled by default] In file included from /usr/include/limits.h:8:0 --------------------------------------------------------------------------- According to the POSIX standard PAGE_SIZE should be defined in <limits.h> [1] which is the case with musl libc if for example _GNU_SOURCE or _BSD_SOURCE are defined which both is the case in netsniff-ng sources. On my i686 test build the interesting part of <bits/limits.h> which itself gets included by <limits.h> looks like this: --------------------------------------------------------------------------- #if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \ || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) || defined(_BSD_SOURCE) #define PAGE_SIZE 4096 #define LONG_BIT 64 #endif --------------------------------------------------------------------------- Note: Besides that I noticed that currently getpagesize(2) is used, which is considered legacy and has been dropped with POSIX.1-2001 [2]. According to getpagesize(2) [2] portable applications should use sysconf(3) [3] By using getpagesize(2) unconditionally the intention was maybe to always use the run time configuration value of PAGE_SIZE as returned by the kernel. At least in the case of musl libc and applying this change this would not be the case anymore as the static PAGE_SIZE value from the header would be used! References: [1] http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html [2] http://man7.org/linux/man-pages/man2/getpagesize.2.html [3] http://man7.org/linux/man-pages/man3/sysconf.3.html Signed-off-by: Christian Wiese <chris@opensde.org> Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
-rw-r--r--built_in.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/built_in.h b/built_in.h
index a3b7bf8..8dd1824 100644
--- a/built_in.h
+++ b/built_in.h
@@ -178,7 +178,9 @@ typedef uint8_t u8;
# define bug() assert(0)
#endif
-#define PAGE_SIZE (getpagesize())
+#ifndef PAGE_SIZE
+# define PAGE_SIZE (getpagesize())
+#endif
#define PAGE_MASK (~(PAGE_SIZE - 1))
#define PAGE_ALIGN(addr) (((addr) + PAGE_SIZE - 1) & PAGE_MASK)