[PATCH 2/9] seccomp.2: Use syscall() in the example code

From: Stephen Kitt <steve@sk2.org>
To: Alejandro Colomar <alx.manpages@gmail.com>,
	Michael Kerrisk <mtk.manpages@gmail.com>
Cc: linux-man@vger.kernel.org, Stephen Kitt <steve@sk2.org>
Subject: [PATCH 2/9] seccomp.2: Use syscall() in the example code
Date: Fri,  7 Jan 2022 17:46:14 +0100	[thread overview]
Message-ID: <20220107164621.275794-2-steve@sk2.org> (raw)
In-Reply-To: <20220107164621.275794-1-steve@sk2.org>

Since seccomp() doesn't exist in glibc, avoid relying on it, and use
syscall() instead. This updates the example program to match the
documentation, which was updated in commit 5945cd7bd3c3 ("seccomp.2:
Use syscall(SYS_...); for system calls without a wrapper").

Signed-off-by: Stephen Kitt <steve@sk2.org>
---
 man2/seccomp.2 | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/man2/seccomp.2 b/man2/seccomp.2
index a3421871f..67928ed3f 100644
--- a/man2/seccomp.2
+++ b/man2/seccomp.2
@@ -1133,6 +1133,7 @@ cecilia
 #include <linux/filter.h>
 #include <linux/seccomp.h>
 #include <sys/prctl.h>
+#include <sys/syscall.h>
 
 #define X32_SYSCALL_BIT 0x40000000
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
@@ -1190,7 +1191,7 @@ install_filter(int syscall_nr, int t_arch, int f_errno)
         .filter = filter,
     };
 
-    if (seccomp(SECCOMP_SET_MODE_FILTER, 0, &prog)) {
+    if (syscall(SYS_seccomp, SECCOMP_SET_MODE_FILTER, 0, &prog)) {
         perror("seccomp");
         return 1;
     }
-- 
2.30.2

