Unbloat build config

- 10.5% reduction of o//depend dependency graph
- 8.8% reduction in latency of make command
- Fix issue with temporary file cleanup

There's a new -w option in compile.com that turns off the recent
Landlock output path workaround for "good commands" which do not
unlink() the output file like GNU tooling does.

Our new GNU Make unveil sandboxing appears to have zero overhead
in the grand scheme of things. Full builds are pretty fast since
the only thing that's actually slowed us down is probably libcxx

    make -j16 MODE=rel
    RL: took 85,732,063µs wall time
    RL: ballooned to 323,612kb in size
    RL: needed 828,560,521µs cpu (11% kernel)
    RL: caused 39,080,670 page faults (99% memcpy)
    RL: 350,073 context switches (72% consensual)
    RL: performed 0 reads and 11,494,960 write i/o operations

pledge() and unveil() no longer consider ENOSYS to be an error.
These functions have also been added to Python's cosmo module.

This change also removes some WIN32 APIs and System Five magnums
which we're not using and it's doubtful anyone else would be too
This commit is contained in:
Justine Tunney 2022-08-10 01:32:17 -07:00
parent 133c693650
commit ae5d06dc53
1423 changed files with 2213 additions and 5560 deletions

View file

@ -47,8 +47,9 @@
#define Eperm 1
#define Sigabrt 6
#define Enosys 38
#define Einval 22
#define Sigsys 31
#define Enosys 38
#define Sig_Setmask 2
#define Sa_Siginfo 4
#define Sa_Restorer 0x04000000
@ -84,6 +85,356 @@ struct Filter {
struct sock_filter p[700];
};
static const struct thatispacked SyscallName {
uint16_t n;
const char *const s;
} kSyscallName[] = {
{__NR_linux_exit, "exit"}, //
{__NR_linux_exit_group, "exit_group"}, //
{__NR_linux_read, "read"}, //
{__NR_linux_write, "write"}, //
{__NR_linux_open, "open"}, //
{__NR_linux_close, "close"}, //
{__NR_linux_stat, "stat"}, //
{__NR_linux_fstat, "fstat"}, //
{__NR_linux_lstat, "lstat"}, //
{__NR_linux_poll, "poll"}, //
{__NR_linux_ppoll, "ppoll"}, //
{__NR_linux_brk, "brk"}, //
{__NR_linux_sigreturn, "sigreturn"}, //
{__NR_linux_lseek, "lseek"}, //
{__NR_linux_mmap, "mmap"}, //
{__NR_linux_msync, "msync"}, //
{__NR_linux_mprotect, "mprotect"}, //
{__NR_linux_munmap, "munmap"}, //
{__NR_linux_sigaction, "sigaction"}, //
{__NR_linux_sigprocmask, "sigprocmask"}, //
{__NR_linux_ioctl, "ioctl"}, //
{__NR_linux_pread, "pread"}, //
{__NR_linux_pwrite, "pwrite"}, //
{__NR_linux_readv, "readv"}, //
{__NR_linux_writev, "writev"}, //
{__NR_linux_access, "access"}, //
{__NR_linux_pipe, "pipe"}, //
{__NR_linux_select, "select"}, //
{__NR_linux_pselect6, "pselect6"}, //
{__NR_linux_sched_yield, "sched_yield"}, //
{__NR_linux_mremap, "mremap"}, //
{__NR_linux_mincore, "mincore"}, //
{__NR_linux_madvise, "madvise"}, //
{__NR_linux_shmget, "shmget"}, //
{__NR_linux_shmat, "shmat"}, //
{__NR_linux_shmctl, "shmctl"}, //
{__NR_linux_dup, "dup"}, //
{__NR_linux_dup2, "dup2"}, //
{__NR_linux_pause, "pause"}, //
{__NR_linux_nanosleep, "nanosleep"}, //
{__NR_linux_getitimer, "getitimer"}, //
{__NR_linux_setitimer, "setitimer"}, //
{__NR_linux_alarm, "alarm"}, //
{__NR_linux_getpid, "getpid"}, //
{__NR_linux_sendfile, "sendfile"}, //
{__NR_linux_socket, "socket"}, //
{__NR_linux_connect, "connect"}, //
{__NR_linux_accept, "accept"}, //
{__NR_linux_sendto, "sendto"}, //
{__NR_linux_recvfrom, "recvfrom"}, //
{__NR_linux_sendmsg, "sendmsg"}, //
{__NR_linux_recvmsg, "recvmsg"}, //
{__NR_linux_shutdown, "shutdown"}, //
{__NR_linux_bind, "bind"}, //
{__NR_linux_listen, "listen"}, //
{__NR_linux_getsockname, "getsockname"}, //
{__NR_linux_getpeername, "getpeername"}, //
{__NR_linux_socketpair, "socketpair"}, //
{__NR_linux_setsockopt, "setsockopt"}, //
{__NR_linux_getsockopt, "getsockopt"}, //
{__NR_linux_fork, "fork"}, //
{__NR_linux_vfork, "vfork"}, //
{__NR_linux_execve, "execve"}, //
{__NR_linux_wait4, "wait4"}, //
{__NR_linux_kill, "kill"}, //
{__NR_linux_clone, "clone"}, //
{__NR_linux_tkill, "tkill"}, //
{__NR_linux_futex, "futex"}, //
{__NR_linux_set_robust_list, "set_robust_list"}, //
{__NR_linux_get_robust_list, "get_robust_list"}, //
{__NR_linux_uname, "uname"}, //
{__NR_linux_semget, "semget"}, //
{__NR_linux_semop, "semop"}, //
{__NR_linux_semctl, "semctl"}, //
{__NR_linux_shmdt, "shmdt"}, //
{__NR_linux_msgget, "msgget"}, //
{__NR_linux_msgsnd, "msgsnd"}, //
{__NR_linux_msgrcv, "msgrcv"}, //
{__NR_linux_msgctl, "msgctl"}, //
{__NR_linux_fcntl, "fcntl"}, //
{__NR_linux_flock, "flock"}, //
{__NR_linux_fsync, "fsync"}, //
{__NR_linux_fdatasync, "fdatasync"}, //
{__NR_linux_truncate, "truncate"}, //
{__NR_linux_ftruncate, "ftruncate"}, //
{__NR_linux_getcwd, "getcwd"}, //
{__NR_linux_chdir, "chdir"}, //
{__NR_linux_fchdir, "fchdir"}, //
{__NR_linux_rename, "rename"}, //
{__NR_linux_mkdir, "mkdir"}, //
{__NR_linux_rmdir, "rmdir"}, //
{__NR_linux_creat, "creat"}, //
{__NR_linux_link, "link"}, //
{__NR_linux_unlink, "unlink"}, //
{__NR_linux_symlink, "symlink"}, //
{__NR_linux_readlink, "readlink"}, //
{__NR_linux_chmod, "chmod"}, //
{__NR_linux_fchmod, "fchmod"}, //
{__NR_linux_chown, "chown"}, //
{__NR_linux_fchown, "fchown"}, //
{__NR_linux_lchown, "lchown"}, //
{__NR_linux_umask, "umask"}, //
{__NR_linux_gettimeofday, "gettimeofday"}, //
{__NR_linux_getrlimit, "getrlimit"}, //
{__NR_linux_getrusage, "getrusage"}, //
{__NR_linux_sysinfo, "sysinfo"}, //
{__NR_linux_times, "times"}, //
{__NR_linux_ptrace, "ptrace"}, //
{__NR_linux_syslog, "syslog"}, //
{__NR_linux_getuid, "getuid"}, //
{__NR_linux_getgid, "getgid"}, //
{__NR_linux_getppid, "getppid"}, //
{__NR_linux_getpgrp, "getpgrp"}, //
{__NR_linux_setsid, "setsid"}, //
{__NR_linux_getsid, "getsid"}, //
{__NR_linux_getpgid, "getpgid"}, //
{__NR_linux_setpgid, "setpgid"}, //
{__NR_linux_geteuid, "geteuid"}, //
{__NR_linux_getegid, "getegid"}, //
{__NR_linux_getgroups, "getgroups"}, //
{__NR_linux_setgroups, "setgroups"}, //
{__NR_linux_setreuid, "setreuid"}, //
{__NR_linux_setregid, "setregid"}, //
{__NR_linux_setuid, "setuid"}, //
{__NR_linux_setgid, "setgid"}, //
{__NR_linux_setresuid, "setresuid"}, //
{__NR_linux_setresgid, "setresgid"}, //
{__NR_linux_getresuid, "getresuid"}, //
{__NR_linux_getresgid, "getresgid"}, //
{__NR_linux_sigpending, "sigpending"}, //
{__NR_linux_sigsuspend, "sigsuspend"}, //
{__NR_linux_sigaltstack, "sigaltstack"}, //
{__NR_linux_mknod, "mknod"}, //
{__NR_linux_mknodat, "mknodat"}, //
{__NR_linux_statfs, "statfs"}, //
{__NR_linux_fstatfs, "fstatfs"}, //
{__NR_linux_getpriority, "getpriority"}, //
{__NR_linux_setpriority, "setpriority"}, //
{__NR_linux_mlock, "mlock"}, //
{__NR_linux_munlock, "munlock"}, //
{__NR_linux_mlockall, "mlockall"}, //
{__NR_linux_munlockall, "munlockall"}, //
{__NR_linux_setrlimit, "setrlimit"}, //
{__NR_linux_chroot, "chroot"}, //
{__NR_linux_sync, "sync"}, //
{__NR_linux_acct, "acct"}, //
{__NR_linux_settimeofday, "settimeofday"}, //
{__NR_linux_mount, "mount"}, //
{__NR_linux_reboot, "reboot"}, //
{__NR_linux_quotactl, "quotactl"}, //
{__NR_linux_setfsuid, "setfsuid"}, //
{__NR_linux_setfsgid, "setfsgid"}, //
{__NR_linux_capget, "capget"}, //
{__NR_linux_capset, "capset"}, //
{__NR_linux_sigtimedwait, "sigtimedwait"}, //
{__NR_linux_rt_sigqueueinfo, "rt_sigqueueinfo"}, //
{__NR_linux_personality, "personality"}, //
{__NR_linux_ustat, "ustat"}, //
{__NR_linux_sysfs, "sysfs"}, //
{__NR_linux_sched_setparam, "sched_setparam"}, //
{__NR_linux_sched_getparam, "sched_getparam"}, //
{__NR_linux_sched_setscheduler, "sched_setscheduler"}, //
{__NR_linux_sched_getscheduler, "sched_getscheduler"}, //
{__NR_linux_sched_get_priority_max, "sched_get_priority_max"}, //
{__NR_linux_sched_get_priority_min, "sched_get_priority_min"}, //
{__NR_linux_sched_rr_get_interval, "sched_rr_get_interval"}, //
{__NR_linux_vhangup, "vhangup"}, //
{__NR_linux_modify_ldt, "modify_ldt"}, //
{__NR_linux_pivot_root, "pivot_root"}, //
{__NR_linux__sysctl, "_sysctl"}, //
{__NR_linux_prctl, "prctl"}, //
{__NR_linux_arch_prctl, "arch_prctl"}, //
{__NR_linux_adjtimex, "adjtimex"}, //
{__NR_linux_umount2, "umount2"}, //
{__NR_linux_swapon, "swapon"}, //
{__NR_linux_swapoff, "swapoff"}, //
{__NR_linux_sethostname, "sethostname"}, //
{__NR_linux_setdomainname, "setdomainname"}, //
{__NR_linux_iopl, "iopl"}, //
{__NR_linux_ioperm, "ioperm"}, //
{__NR_linux_init_module, "init_module"}, //
{__NR_linux_delete_module, "delete_module"}, //
{__NR_linux_gettid, "gettid"}, //
{__NR_linux_readahead, "readahead"}, //
{__NR_linux_setxattr, "setxattr"}, //
{__NR_linux_fsetxattr, "fsetxattr"}, //
{__NR_linux_getxattr, "getxattr"}, //
{__NR_linux_fgetxattr, "fgetxattr"}, //
{__NR_linux_listxattr, "listxattr"}, //
{__NR_linux_flistxattr, "flistxattr"}, //
{__NR_linux_removexattr, "removexattr"}, //
{__NR_linux_fremovexattr, "fremovexattr"}, //
{__NR_linux_lsetxattr, "lsetxattr"}, //
{__NR_linux_lgetxattr, "lgetxattr"}, //
{__NR_linux_llistxattr, "llistxattr"}, //
{__NR_linux_lremovexattr, "lremovexattr"}, //
{__NR_linux_sched_setaffinity, "sched_setaffinity"}, //
{__NR_linux_sched_getaffinity, "sched_getaffinity"}, //
{__NR_linux_io_setup, "io_setup"}, //
{__NR_linux_io_destroy, "io_destroy"}, //
{__NR_linux_io_getevents, "io_getevents"}, //
{__NR_linux_io_submit, "io_submit"}, //
{__NR_linux_io_cancel, "io_cancel"}, //
{__NR_linux_lookup_dcookie, "lookup_dcookie"}, //
{__NR_linux_epoll_create, "epoll_create"}, //
{__NR_linux_epoll_wait, "epoll_wait"}, //
{__NR_linux_epoll_ctl, "epoll_ctl"}, //
{__NR_linux_getdents, "getdents"}, //
{__NR_linux_set_tid_address, "set_tid_address"}, //
{__NR_linux_restart_syscall, "restart_syscall"}, //
{__NR_linux_semtimedop, "semtimedop"}, //
{__NR_linux_fadvise, "fadvise"}, //
{__NR_linux_timer_create, "timer_create"}, //
{__NR_linux_timer_settime, "timer_settime"}, //
{__NR_linux_timer_gettime, "timer_gettime"}, //
{__NR_linux_timer_getoverrun, "timer_getoverrun"}, //
{__NR_linux_timer_delete, "timer_delete"}, //
{__NR_linux_clock_settime, "clock_settime"}, //
{__NR_linux_clock_gettime, "clock_gettime"}, //
{__NR_linux_clock_getres, "clock_getres"}, //
{__NR_linux_clock_nanosleep, "clock_nanosleep"}, //
{__NR_linux_tgkill, "tgkill"}, //
{__NR_linux_mbind, "mbind"}, //
{__NR_linux_set_mempolicy, "set_mempolicy"}, //
{__NR_linux_get_mempolicy, "get_mempolicy"}, //
{__NR_linux_mq_open, "mq_open"}, //
{__NR_linux_mq_unlink, "mq_unlink"}, //
{__NR_linux_mq_timedsend, "mq_timedsend"}, //
{__NR_linux_mq_timedreceive, "mq_timedreceive"}, //
{__NR_linux_mq_notify, "mq_notify"}, //
{__NR_linux_mq_getsetattr, "mq_getsetattr"}, //
{__NR_linux_kexec_load, "kexec_load"}, //
{__NR_linux_waitid, "waitid"}, //
{__NR_linux_add_key, "add_key"}, //
{__NR_linux_request_key, "request_key"}, //
{__NR_linux_keyctl, "keyctl"}, //
{__NR_linux_ioprio_set, "ioprio_set"}, //
{__NR_linux_ioprio_get, "ioprio_get"}, //
{__NR_linux_inotify_init, "inotify_init"}, //
{__NR_linux_inotify_add_watch, "inotify_add_watch"}, //
{__NR_linux_inotify_rm_watch, "inotify_rm_watch"}, //
{__NR_linux_openat, "openat"}, //
{__NR_linux_mkdirat, "mkdirat"}, //
{__NR_linux_fchownat, "fchownat"}, //
{__NR_linux_utime, "utime"}, //
{__NR_linux_utimes, "utimes"}, //
{__NR_linux_futimesat, "futimesat"}, //
{__NR_linux_fstatat, "fstatat"}, //
{__NR_linux_unlinkat, "unlinkat"}, //
{__NR_linux_renameat, "renameat"}, //
{__NR_linux_linkat, "linkat"}, //
{__NR_linux_symlinkat, "symlinkat"}, //
{__NR_linux_readlinkat, "readlinkat"}, //
{__NR_linux_fchmodat, "fchmodat"}, //
{__NR_linux_faccessat, "faccessat"}, //
{__NR_linux_unshare, "unshare"}, //
{__NR_linux_splice, "splice"}, //
{__NR_linux_tee, "tee"}, //
{__NR_linux_sync_file_range, "sync_file_range"}, //
{__NR_linux_vmsplice, "vmsplice"}, //
{__NR_linux_migrate_pages, "migrate_pages"}, //
{__NR_linux_move_pages, "move_pages"}, //
{__NR_linux_preadv, "preadv"}, //
{__NR_linux_pwritev, "pwritev"}, //
{__NR_linux_utimensat, "utimensat"}, //
{__NR_linux_fallocate, "fallocate"}, //
{__NR_linux_accept4, "accept4"}, //
{__NR_linux_dup3, "dup3"}, //
{__NR_linux_pipe2, "pipe2"}, //
{__NR_linux_epoll_pwait, "epoll_pwait"}, //
{__NR_linux_epoll_create1, "epoll_create1"}, //
{__NR_linux_perf_event_open, "perf_event_open"}, //
{__NR_linux_inotify_init1, "inotify_init1"}, //
{__NR_linux_rt_tgsigqueueinfo, "rt_tgsigqueueinfo"}, //
{__NR_linux_signalfd, "signalfd"}, //
{__NR_linux_signalfd4, "signalfd4"}, //
{__NR_linux_eventfd, "eventfd"}, //
{__NR_linux_eventfd2, "eventfd2"}, //
{__NR_linux_timerfd_create, "timerfd_create"}, //
{__NR_linux_timerfd_settime, "timerfd_settime"}, //
{__NR_linux_timerfd_gettime, "timerfd_gettime"}, //
{__NR_linux_recvmmsg, "recvmmsg"}, //
{__NR_linux_fanotify_init, "fanotify_init"}, //
{__NR_linux_fanotify_mark, "fanotify_mark"}, //
{__NR_linux_prlimit, "prlimit"}, //
{__NR_linux_name_to_handle_at, "name_to_handle_at"}, //
{__NR_linux_open_by_handle_at, "open_by_handle_at"}, //
{__NR_linux_clock_adjtime, "clock_adjtime"}, //
{__NR_linux_syncfs, "syncfs"}, //
{__NR_linux_sendmmsg, "sendmmsg"}, //
{__NR_linux_setns, "setns"}, //
{__NR_linux_getcpu, "getcpu"}, //
{__NR_linux_process_vm_readv, "process_vm_readv"}, //
{__NR_linux_process_vm_writev, "process_vm_writev"}, //
{__NR_linux_kcmp, "kcmp"}, //
{__NR_linux_finit_module, "finit_module"}, //
{__NR_linux_sched_setattr, "sched_setattr"}, //
{__NR_linux_sched_getattr, "sched_getattr"}, //
{__NR_linux_renameat2, "renameat2"}, //
{__NR_linux_seccomp, "seccomp"}, //
{__NR_linux_getrandom, "getrandom"}, //
{__NR_linux_memfd_create, "memfd_create"}, //
{__NR_linux_kexec_file_load, "kexec_file_load"}, //
{__NR_linux_bpf, "bpf"}, //
{__NR_linux_execveat, "execveat"}, //
{__NR_linux_userfaultfd, "userfaultfd"}, //
{__NR_linux_membarrier, "membarrier"}, //
{__NR_linux_mlock2, "mlock2"}, //
{__NR_linux_copy_file_range, "copy_file_range"}, //
{__NR_linux_preadv2, "preadv2"}, //
{__NR_linux_pwritev2, "pwritev2"}, //
{__NR_linux_pkey_mprotect, "pkey_mprotect"}, //
{__NR_linux_pkey_alloc, "pkey_alloc"}, //
{__NR_linux_pkey_free, "pkey_free"}, //
{__NR_linux_statx, "statx"}, //
{__NR_linux_io_pgetevents, "io_pgetevents"}, //
{__NR_linux_rseq, "rseq"}, //
{__NR_linux_pidfd_send_signal, "pidfd_send_signal"}, //
{__NR_linux_io_uring_setup, "io_uring_setup"}, //
{__NR_linux_io_uring_enter, "io_uring_enter"}, //
{__NR_linux_io_uring_register, "io_uring_register"}, //
{__NR_linux_open_tree, "open_tree"}, //
{__NR_linux_move_mount, "move_mount"}, //
{__NR_linux_fsopen, "fsopen"}, //
{__NR_linux_fsconfig, "fsconfig"}, //
{__NR_linux_fsmount, "fsmount"}, //
{__NR_linux_fspick, "fspick"}, //
{__NR_linux_pidfd_open, "pidfd_open"}, //
{__NR_linux_clone3, "clone3"}, //
{__NR_linux_close_range, "close_range"}, //
{__NR_linux_openat2, "openat2"}, //
{__NR_linux_pidfd_getfd, "pidfd_getfd"}, //
{__NR_linux_faccessat2, "faccessat2"}, //
{__NR_linux_process_madvise, "process_madvise"}, //
{__NR_linux_epoll_pwait2, "epoll_pwait2"}, //
{__NR_linux_mount_setattr, "mount_setattr"}, //
{__NR_linux_quotactl_fd, "quotactl_fd"}, //
{__NR_linux_landlock_create_ruleset, "landlock_create_ruleset"}, //
{__NR_linux_landlock_add_rule, "landlock_add_rule"}, //
{__NR_linux_landlock_restrict_self, "landlock_restrict_self"}, //
{__NR_linux_memfd_secret, "memfd_secret"}, //
{__NR_linux_process_mrelease, "process_mrelease"}, //
{__NR_linux_futex_waitv, "futex_waitv"}, //
{__NR_linux_set_mempolicy_home_node, "set_mempolicy_home_node"}, //
};
static const uint16_t kPledgeDefault[] = {
__NR_linux_exit, // thread return / exit()
};
@ -584,6 +935,16 @@ static privileged void KillThisThread(void) {
: "rcx", "r11", "memory");
}
static privileged const char *GetSyscallName(uint16_t n) {
int i;
for (i = 0; i < ARRAYLEN(kSyscallName); ++i) {
if (kSyscallName[i].n == n) {
return kSyscallName[i].s;
}
}
return "unknown";
}
static privileged int HasSyscall(struct Pledges *p, uint16_t n) {
int i;
for (i = 0; i < p->len; ++i) {
@ -606,23 +967,16 @@ static privileged void OnSigSys(int sig, siginfo_t *si, ucontext_t *ctx) {
FixCpy(ord, si->si_syscall, 12);
HexCpy(rip, ctx->uc_mcontext.rip);
for (found = i = 0; i < ARRAYLEN(kPledge); ++i) {
switch (HasSyscall(kPledge + i, si->si_syscall)) {
case 1:
Log("error: should pledge ", kPledge[i].name, //
" (ord=", ord, " rip=", rip, ")\n", 0);
found = true;
break;
case 2:
Log("error: maybe pledge ", kPledge[i].name, //
" (ord=", ord, " rip=", rip, ")\n", 0);
found = true;
break;
default:
break;
if (HasSyscall(kPledge + i, si->si_syscall)) {
Log("error: pledge ", kPledge[i].name, " for ",
GetSyscallName(si->si_syscall), " (ord=", ord, " rip=", rip, ")\n",
0);
found = true;
}
}
if (!found) {
Log("error: bad syscall (ord=", ord, " rip=", rip, ")\n", 0);
Log("error: bad syscall (", GetSyscallName(si->si_syscall), " ord=", ord,
" rip=", rip, ")\n", 0);
}
switch (mode) {
case kPledgeModeKillProcess:
@ -1554,8 +1908,8 @@ static privileged void AppendPledge(struct Filter *f, //
privileged int sys_pledge_linux(unsigned long ipromises, //
enum PledgeMode mode, //
bool want_msyscall) { //
int i, rc = -1;
struct Filter f;
int i, e, rc = -1;
struct sock_filter sf[1] = {BPF_STMT(BPF_RET | BPF_K, 0)};
CheckLargeStackAllocation(&f, sizeof(f));
f.n = 0;
@ -1610,10 +1964,24 @@ privileged int sys_pledge_linux(unsigned long ipromises, //
AppendFilter(&f, PLEDGE(sf));
}
// drop privileges
//
// PR_SET_SECCOMP (Linux 2.6.23+) will refuse to work if
// PR_SET_NO_NEW_PRIVS (Linux 3.5+) wasn't called so we punt the error
// detection to the seccomp system call below.
Prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
// register our seccomp filter with the kernel
if ((rc = Prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0)) != -1) {
struct sock_fprog sandbox = {.len = f.n, .filter = f.p};
rc = Prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &sandbox, 0, 0);
struct sock_fprog sandbox = {.len = f.n, .filter = f.p};
rc = Prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &sandbox, 0, 0);
// the EINVAL error could mean a lot of things. it could mean the bpf
// code is broken. it could also mean we're running on RHEL5 which
// doesn't have SECCOMP support. since we don't consider lack of
// system support for security to be an error, we distinguish these
// two cases by running a simpler SECCOMP operation.
if (rc == -Einval && Prctl(PR_GET_SECCOMP, 0, 0, 0, 0) == -Einval) {
rc = 0; // -Enosys
}
return rc;