-static int apply_seccomp(uint32_t *syscall_filter) {
- static const struct sock_filter header[] = {
- VALIDATE_ARCHITECTURE,
- EXAMINE_SYSCALL
- };
- static const struct sock_filter footer[] = {
- _KILL_PROCESS
- };
-
- int i;
- unsigned n;
- struct sock_filter *f;
- struct sock_fprog prog = {};
-
- assert(syscall_filter);
-
- /* First: count the syscalls to check for */
- for (i = 0, n = 0; i < syscall_max(); i++)
- if (syscall_filter[i >> 4] & (1 << (i & 31)))
- n++;
-
- /* Second: build the filter program from a header the syscall
- * matches and the footer */
- f = alloca(sizeof(struct sock_filter) * (ELEMENTSOF(header) + 2*n + ELEMENTSOF(footer)));
- memcpy(f, header, sizeof(header));