_syscall_gate.nx source

1// _syscall_gate.nx -- gate for the SYSCALL ABI (args + dispatch + return + resume). NO mocks. 2// 3// (1) SYSCALL ROUND-TRIP -- emits + runs nx_syscall_emit: a U-mode program makes two PUTC 4// syscalls + EXIT; the M-mode kernel dispatches on a0, emits a1, advances mepc, and mret's 5// back so the user RESUMES. Serial "AB" + clean halt = both syscalls serviced AND the user 6// resumed between them (the return path works). 7// (2) CONTROL (resume is real) -- re-emit with advance=0 (kernel does NOT advance mepc past the 8// ecall): the user re-runs the first syscall forever -> "AAAA..." (step cap), never reaching 9// "B". Proves "AB" REQUIRES the mepc+4 + mret resume path (not a fixed transcript). 10// 11// Evidence -> knowledge/status/priv.log (SYSCALLGATE row). Sovereign. license_tier: ORIGINAL 12import "nx_syscalls.nx" 13 14const S_EMIT: *u8 = "_offc/nx_syscall_emit.elf" 15const S_SOV: *u8 = "_offc/nx_boot_run_sov.elf" 16const S_BIN: *u8 = "runtime/_hdl_build/_syscall_virt.bin" 17 18func g_p(s: *u8) -> i64 { var n: i64=0; while s[n]!=(0 as u8){n=n+1} sys_write(1,s,n); return 0 } 19func g_fp(fd: i64, s: *u8) -> i64 { var n: i64=0; while s[n]!=(0 as u8){n=n+1} sys_write(fd,s,n); return 0 } 20func g_fn(fd: i64, v: i64) -> i64 { let bb: *u8=sys_mmap(28); var m: i64=v; if m<0{m=0-m}; let t: *u8=sys_mmap(28); var k: i64=0; if m==0{t[0]=48;k=1}; while m>0{t[k]=(48+(m%10)) as u8;m=m/10;k=k+1}; var i: i64=0; while i<k{bb[i]=t[k-1-i];i=i+1}; sys_write(fd,bb,k); return 0 } 21 22func g_run(prog: *u8, a1: *u8, a2: *u8, outpath: *u8) -> i64 { 23 let pid: i64 = sys_fork() 24 if pid == 0 { 25 if outpath != (0 as *u8) { let ofd: i64 = sys_openat_wr(outpath, 0x1a4); if ofd >= 0 { sys_dup3(ofd, 1, 0); sys_dup3(ofd, 2, 0) } } 26 let argv: *i64 = sys_mmap(32) as *i64 27 argv[0] = prog as i64 28 var k: i64 = 1 29 if a1 != (0 as *u8) { argv[k] = a1 as i64; k = k + 1 } 30 if a2 != (0 as *u8) { argv[k] = a2 as i64; k = k + 1 } 31 argv[k] = 0 32 let envp: *i64 = sys_mmap(16) as *i64 33 envp[0] = "PATH=/usr/bin:/bin" as *u8 as i64; envp[1] = 0 34 sys_execve(prog, argv, envp) 35 sys_exit(127) 36 } 37 let st: *i64 = sys_mmap(16) as *i64 38 sys_wait4(pid, st, 0) 39 let sg: i64 = st[0] & 0x7f 40 if sg != 0 { return 128 + sg } 41 return (st[0] >> 8) & 0xff 42} 43func g_read(path: *u8, buf: *u8, cap: i64) -> i64 { 44 let fd: i64 = sys_openat_rd(path) 45 if fd < 0 { return 0 } 46 var n: i64 = 0 47 var go: i64 = 1 48 while go == 1 { let r: i64 = sys_read(fd, (buf as i64 + n) as *u8, cap - 1 - n); if r <= 0 { go = 0 } else { n = n + r } if n >= cap - 1 { go = 0 } } 49 sys_close(fd) 50 return n 51} 52func g_has(buf: *u8, n: i64, pat: *u8, pl: i64) -> i64 { 53 if pl <= 0 { return 0 } 54 var i: i64 = 0 55 while i + pl <= n { var k: i64=0; var hit: i64=1; while k<pl { if buf[i+k]!=pat[k]{hit=0;k=pl}else{k=k+1} } if hit==1 { return 1 } i=i+1 } 56 return 0 57} 58 59func main() -> i64 { 60 g_p("=== syscall ABI gate (U-mode args + kernel dispatch + mepc+4 + mret resume) ===\n" as *u8) 61 let lfd: i64 = sys_openat_append("knowledge/status/priv.log" as *u8, 0x1a4) 62 63 // (1) round-trip: AB 64 g_run(S_EMIT, 0 as *u8, 0 as *u8, "/tmp/_sc_emit.out" as *u8) 65 g_run(S_SOV, S_BIN, 0 as *u8, "/tmp/_sc_main.txt" as *u8) 66 let mb: *u8 = sys_mmap(65536); let mn: i64 = g_read("/tmp/_sc_main.txt" as *u8, mb, 65536) 67 var rt_ok: i64 = 0 68 if g_has(mb, mn, "AB" as *u8, 2) == 1 { if g_has(mb, mn, "BOOTSOV verdict=GREEN" as *u8, 21) == 1 { rt_ok = 1 } } 69 70 // (2) control: advance=0 -> no resume -> re-loops first syscall -> no "AB" 71 g_run(S_EMIT, "0" as *u8, "/tmp/_sc_ctrl.bin" as *u8, "/tmp/_sc_ctrl_emit.out" as *u8) 72 g_run(S_SOV, "/tmp/_sc_ctrl.bin" as *u8, 0 as *u8, "/tmp/_sc_ctrl.txt" as *u8) 73 let cb: *u8 = sys_mmap(131072); let cn: i64 = g_read("/tmp/_sc_ctrl.txt" as *u8, cb, 131072) 74 var control_ok: i64 = 0 75 if g_has(cb, cn, "AB" as *u8, 2) == 0 { if g_has(cb, cn, "A" as *u8, 1) == 1 { control_ok = 1 } } // A's present, never B 76 77 g_p(" syscall_roundtrip=" as *u8); if rt_ok==1 { g_p("GREEN(AB: two PUTC syscalls serviced + user resumed between them)" as *u8) } else { g_p("RED" as *u8) } 78 g_p(" control_no_resume_no_B=" as *u8); g_fn(1, control_ok); g_p("\n" as *u8) 79 80 var pass: i64 = 0 81 if rt_ok == 1 { if control_ok == 1 { pass = 1 } } 82 if pass == 1 { 83 g_p("SYSCALLGATE verdict=GREEN (working syscall ABI: U-mode passes a0=syscall#/a1=arg, the M-mode kernel dispatches [PUTC emits a1, EXIT halts], advances mepc + mret's back, and the user RESUMES -> AB; the advance=0 control re-loops the first syscall forever [no B] = the resume path is load-bearing. probe=syscall-abi)\n" as *u8) 84 if lfd >= 0 { g_fp(lfd, "SYSCALLGATE verdict=GREEN keystone=syscall-abi probe=syscall-abi args=a0/a1 dispatch=PUTC/EXIT return=mepc+4+mret resume=verified(AB) control=no-advance-no-B epoch=" as *u8); g_fn(lfd, sys_now_realtime_sec()); g_fp(lfd, "\n" as *u8); sys_close(lfd) } 85 sys_exit(0); return 0 86 } 87 g_p("SYSCALLGATE verdict=RED (roundtrip/control not all green)\n" as *u8) 88 if lfd >= 0 { g_fp(lfd, "SYSCALLGATE verdict=RED rt=" as *u8); g_fn(lfd, rt_ok); g_fp(lfd, " control=" as *u8); g_fn(lfd, control_ok); g_fp(lfd, "\n" as *u8); sys_close(lfd) } 89 sys_exit(1) 90 return 1 91}