build: Conditionally defined SYS_* constants

This patch changes the way the per architecture syscall-codes.h is
generated to define __NR* and SYS_* constants only if there are not
already defined.

This way this file could be included in the C files calling syscall()
to ensure the SYS_* constant is defined even if the C library is too
old.

The file syscall-codes.h should be included after the C library header
files.
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

criu/arch/ppc64/Makefile.syscalls

@@ -20,7 +20,9 @@ $(obj)/$(SYS-CODES): $(obj)/syscalls/$(SYS-DEF)
 	$(Q) echo "/* Autogenerated, don't edit */"							>  $@
 	$(Q) echo "#ifndef __ASM_CR_SYSCALL_CODES_H__"							>> $@
 	$(Q) echo "#define __ASM_CR_SYSCALL_CODES_H__"							>> $@
-	$(Q) cat $< | awk '/^__NR/{print "#define", $$1, $$2}'						>> $@
+	$(Q) cat $< | awk '/^__NR/{SYSN=$$1; sub("^__NR", "SYS", SYSN);'\
+	'print "\n#ifndef ", $$1, "\n#define", $$1, $$2, "\n#endif";'\
+	'print "#ifndef ", SYSN, "\n#define ", SYSN, $$1, "\n#endif"}'					>> $@
 	$(Q) echo "#endif /* __ASM_CR_SYSCALL_CODES_H__ */"						>> $@
 cleanup-y		+= $(obj)/$(SYS-CODES)
 

criu/arch/scripts/arm/gen-syscalls.pl

@@ -59,13 +59,16 @@ for (<IN>) {
 	}
 
 	my $code_macro;
+	my $sys_macro;
 	my $sys_name;
 
 	if (/(?<name>\S+)\s+(?<alias>\S+)\s+(?<code64>\d+|\!)\s+(?<code32>(?:\d+|\!))\s+\((?<args>.+)\)/) {
 		$code_macro = "__NR_$+{name}";
+		$sys_macro  = "SYS_$+{name}";
 		$sys_name   = "sys_$+{alias}";
 	} elsif (/(?<name>\S+)\s+(?<code64>\d+|\!)\s+(?<code32>(?:\d+|\!))\s+\((?<args>.+)\)/) {
 		$code_macro = "__NR_$+{name}";
+		$sys_macro  = "SYS_$+{name}";
 		$sys_name   = "sys_$+{name}";
 	} else {
 		unlink $codesout;
@@ -76,7 +79,8 @@ for (<IN>) {
 	}
 
 	if ($+{$code} ne "!") {
-		print CODESOUT "#define $code_macro $+{$code}\n";
+		print CODESOUT "#ifndef $code_macro\n#define $code_macro $+{$code}\n#endif\n";
+		print CODESOUT "#ifndef $sys_macro\n#define $sys_macro $code_macro\n#endif\n";
 		print ASMOUT "syscall $sys_name, $code_macro\n";
 
 	} else {

criu/arch/x86/Makefile.syscalls

@@ -31,7 +31,9 @@ $(obj)/$(SYS-CODES): $(obj)/syscalls/$(SYS-DEF)
 	$(Q) echo "/* Autogenerated, don't edit */"							>  $@
 	$(Q) echo "#ifndef __ASM_CR_SYSCALL_CODES_H__"							>> $@
 	$(Q) echo "#define __ASM_CR_SYSCALL_CODES_H__"							>> $@
-	$(Q) cat $< | awk '/^__NR/{print "#define", $$1, $$2}'						>> $@
+	$(Q) cat $< | awk '/^__NR/{SYSN=$$1; sub("^__NR", "SYS", SYSN);'\
+	'print "\n#ifndef ", $$1, "\n#define", $$1, $$2, "\n#endif";'\
+	'print "#ifndef ", SYSN, "\n#define ", SYSN, $$1, "\n#endif"}'					>> $@
 	$(Q) echo "#endif /* __ASM_CR_SYSCALL_CODES_H__ */"						>> $@
 cleanup-y		+= $(obj)/$(SYS-CODES)