From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Date: Tue, 28 Jul 2020 10:31:31 +0000 (+0200)
Subject: syscall: don't fail if __NR_signalfd is not defined
X-Git-Tag: lxc-5.0.0~378^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3341e204dc1e1da6ecbc1ffbe59fca33f23ca557;p=thirdparty%2Flxc.git

syscall: don't fail if __NR_signalfd is not defined

lxc fails to build if __NR_signalfd is not defined since version 4.0.0
and
https://github.com/lxc/lxc/commit/bed09c9cc0bec7bbd2442fcce4a2a0f03994cb09

However, some architectures don't define __NR_signalfd but only
__NR_signalfd4. This is the case for example for nios2 or csky:
https://github.com/bminor/glibc/blob/f9ac84f92f151e07586c55e14ed628d493a5929d/sysdeps/unix/sysv/linux/nios2/arch-syscall.h
https://github.com/bminor/glibc/blob/f9ac84f92f151e07586c55e14ed628d493a5929d/sysdeps/unix/sysv/linux/csky/arch-syscall.h

Fixes:
 - http://autobuild.buildroot.org/results/75096a48d2dbda57459523db3ed0952e63f93535

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---

diff --git a/src/lxc/syscall_numbers.h b/src/lxc/syscall_numbers.h
index e2e788378..72e4ffe46 100644
--- a/src/lxc/syscall_numbers.h
+++ b/src/lxc/syscall_numbers.h
@@ -228,9 +228,6 @@
 		#if _MIPS_SIM == _MIPS_SIM_ABI64	/* n64 */
 			#define __NR_signalfd 5276
 		#endif
-	#else
-		#define -1
-		#warning "__NR_signalfd not defined for your architecture"
 	#endif
 #endif
 
diff --git a/src/lxc/syscall_wrappers.h b/src/lxc/syscall_wrappers.h
index 220ef65fd..6aaa43722 100644
--- a/src/lxc/syscall_wrappers.h
+++ b/src/lxc/syscall_wrappers.h
@@ -112,8 +112,10 @@ static inline int signalfd(int fd, const sigset_t *mask, int flags)
 	int retval;
 
 	retval = syscall(__NR_signalfd4, fd, mask, _NSIG / 8, flags);
+#ifdef __NR_signalfd
 	if (errno == ENOSYS && flags == 0)
 		retval = syscall(__NR_signalfd, fd, mask, _NSIG / 8);
+#endif
 
 	return retval;
 }