title: How can I find all syscalls that have to be whitelisted for seccomp?
body: <p>I have an existing program that I would like to sandbox using seccomp (v2). </p>
  
  <p>How can I find what seccomp rules I need to allow for the program?</p>
  
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  <p>I've tried adding <code>seccomp_rule_add(ctx, SCMP_ACT_ALLOW, SCMP_SYS(…), 0)</code> for all syscalls printed by <code>strace -xfc a.out</code>, but apparently that wasn't enough, since I'm still getting "SIGSYS, Bad system call" when I run the program with seccomp.</p>