[PATCH] linux: add check for sysctl sycall presence

[Samuel Martin]

# HG changeset patch
# User "Samuel Martin" <s.martin49 at gmail.com>
# Date 1416759425 -3600
#      Sun Nov 23 17:17:05 2014 +0100
# Node ID 3a010d195a5a4249da5552c5de7643f898c9e507
# Parent  1be88123e98c8b0e78602eeb3a8c3eb3444c15f3
linux: add check for sysctl sycall presence

And also disable call to the sysctl function when the sysctl syscall
is disabled in the kernel configuration.

This fixes:
  http://autobuild.buildroot.org/results/730/730105fc0a89b381b3b29192d07f28ef1f13cbb3/build-end.log

Signed-off-by: Samuel Martin <s.martin49 at gmail.com>

diff -r 1be88123e98c -r 3a010d195a5a auto/os/linux
--- a/auto/os/linux	Sat Aug 02 00:30:55 2014 +0200
+++ b/auto/os/linux	Sun Nov 23 17:17:05 2014 +0100
@@ -44,6 +44,20 @@
     have=NGX_HAVE_POSIX_FADVISE . auto/nohave
 fi
 
+# sysctl syscall
+
+ngx_feature="sysctl_syscall"
+ngx_feature_name="NGX_HAVE_SYSCTL_SYSCALL"
+ngx_feature_run=no
+ngx_feature_run_force_result="$ngx_force_have_sysctl_syscall"
+ngx_feature_incs="#include <sys/sysctl.h>"
+ngx_feature_path=
+ngx_feature_libs=
+ngx_feature_test="int name[2] = { CTL_KERN, KERN_RTSIGMAX };
+                  int old;
+                  sysctl(name, 2, &old, sizeof(old), NULL, 0);"
+. auto/feature
+
 # epoll, EPOLLET version
 
 ngx_feature="epoll"
diff -r 1be88123e98c -r 3a010d195a5a src/event/modules/ngx_rtsig_module.c
--- a/src/event/modules/ngx_rtsig_module.c	Sat Aug 02 00:30:55 2014 +0200
+++ b/src/event/modules/ngx_rtsig_module.c	Sun Nov 23 17:17:05 2014 +0100
@@ -621,6 +621,7 @@
 
         if (tested >= rtscf->overflow_test) {
 
+#if (NGX_HAVE_SYSCTL_SYSCALL)
             if (ngx_linux_rtsig_max) {
 
                 /*
@@ -668,7 +669,9 @@
                 }
 
             } else {
-
+#else
+            {
+#endif
                 /*
                  * Linux has not KERN_RTSIGMAX since 2.6.6-mm2
                  * so drain the rt signal queue unconditionally
diff -r 1be88123e98c -r 3a010d195a5a src/os/unix/ngx_linux_config.h
--- a/src/os/unix/ngx_linux_config.h	Sat Aug 02 00:30:55 2014 +0200
+++ b/src/os/unix/ngx_linux_config.h	Sun Nov 23 17:17:05 2014 +0100
@@ -84,8 +84,10 @@
 
 #if (NGX_HAVE_RTSIG)
 #include <poll.h>
+#if (NGX_HAVE_SYSCTL_SYSCALL)
 #include <sys/sysctl.h>
 #endif
+#endif
 
 
 #if (NGX_HAVE_EPOLL)
diff -r 1be88123e98c -r 3a010d195a5a src/os/unix/ngx_linux_init.c
--- a/src/os/unix/ngx_linux_init.c	Sat Aug 02 00:30:55 2014 +0200
+++ b/src/os/unix/ngx_linux_init.c	Sun Nov 23 17:17:05 2014 +0100
@@ -46,7 +46,7 @@
     (void) ngx_cpystrn(ngx_linux_kern_osrelease, (u_char *) u.release,
                        sizeof(ngx_linux_kern_osrelease));
 
-#if (NGX_HAVE_RTSIG)
+#if (NGX_HAVE_RTSIG) && (NGX_HAVE_SYSCTL_SYSCALL)
     {
     int        name[2];
     size_t     len;