nx_fd_hygiene_gate.nx source
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1// nx_fd_hygiene_gate.nx -- prove nx_fd_scrub_inherited() closes inherited fds >= 3 while PRESERVING stdio.
2// This is the regression tooth for the mgmt :18098 fd-leak cure (2026-07-17): if the scrub ever stops closing
3// inherited fds, a supervisor would leak listen sockets into its children again. license_tier: ORIGINAL
4// expect_exit: 0
5import "nx_fd_hygiene.nx"
6import "nx_syscalls.nx"
7
8func w(s: *u8) -> i64 { var n: i64=0; while s[n]!=(0 as u8){n=n+1} sys_write(1,s,n); return 0 }
9func pn(v: i64) -> i64 {
10 let b: *u8 = sys_mmap(32) as *u8
11 var x: i64 = v; if x < 0 { sys_write(1,"-" as *u8,1); x = 0 - x }
12 var i: i64 = 31
13 if x == 0 { b[i] = 48 as u8; i = i - 1 }
14 while x > 0 { b[i] = (48 + x % 10) as u8; x = x / 10; i = i - 1 }
15 sys_write(1, (b as i64 + i + 1) as *u8, 31 - i)
16 return 0
17}
18
19func main() -> i64 {
20 w("=== nx_fd_hygiene_gate -- inherited-fd scrub (mgmt :18098 leak cure) ===\n" as *u8)
21 var fails: i64 = 0
22
23 // open 3 marker fds (>= 3); /dev/null is always openable.
24 let a: i64 = sys_openat_rd("/dev/null" as *u8)
25 let b: i64 = sys_openat_rd("/dev/null" as *u8)
26 let c: i64 = sys_openat_rd("/dev/null" as *u8)
27 w("T1 opened markers a=" as *u8); pn(a); w(" b=" as *u8); pn(b); w(" c=" as *u8); pn(c); w("\n" as *u8)
28 if a < 3 { fails = fails + 1 }
29 if b < 3 { fails = fails + 1 }
30 if c < 3 { fails = fails + 1 }
31
32 // scrub -- must close a,b,c (and any other inherited fd >= 3).
33 let closed: i64 = nx_fd_scrub_inherited()
34 w("T2 scrub closed " as *u8); pn(closed); w(" fds\n" as *u8)
35 if closed < 3 { fails = fails + 1 }
36
37 // each marker is now CLOSED: re-closing returns EBADF (nonzero), never 0.
38 if sys_close(a) == 0 { fails = fails + 1; w(" BAD a still open\n" as *u8) }
39 if sys_close(b) == 0 { fails = fails + 1; w(" BAD b still open\n" as *u8) }
40 if sys_close(c) == 0 { fails = fails + 1; w(" BAD c still open\n" as *u8) }
41
42 // NEG-CONTROL: stdio survived -- this very write proves fd 1 is still open after the scrub.
43 w("T3 stdio preserved (you are reading this on fd 1 AFTER the scrub)\n" as *u8)
44
45 if fails == 0 { w("FD-HYGIENE-GATE 3/3 verdict=GREEN -- scrub closes inherited fds>=3, preserves stdio\n" as *u8); sys_exit(0); return 0 }
46 w("FD-HYGIENE-GATE RED fails=" as *u8); pn(fails); w("\n" as *u8)
47 sys_exit(1); return 1
48}