samples: fix pidfd-metadata compilation

Define __NR_pidfd_send_signal if it isn't to prevent a compilation error. To make pidfd-metadata compile on all arches, irrespective of whether or not syscall numbers are assigned, define the syscall number to -1. If it isn't defined this will cause the kernel to return -ENOSYS. Fixes: 43c6afe ("samples: show race-free pidfd metadata access") Reported-by: Arnd Bergmann <[email protected]> Reported-by: Guenter Roeck <[email protected]> Cc: Christian Brauner <[email protected]> Signed-off-by: Guenter Roeck <[email protected]> [[email protected]: tweak commit message] Signed-off-by: Christian Brauner <[email protected]>
chewitt · Jun 5, 2019 · 7c33277 · 7c33277
1 parent f2c7c76
commit 7c33277
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/samples/pidfd/pidfd-metadata.c b/samples/pidfd/pidfd-metadata.c
@@ -21,6 +21,10 @@
 #define CLONE_PIDFD 0x00001000
 #endif
 
+#ifndef __NR_pidfd_send_signal
+#define __NR_pidfd_send_signal -1
+#endif
+
 static int do_child(void *args)
 {
 	printf("%d\n", getpid());