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feat: process exit codes, posix_spawn, 4 KiB command lines

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Groundwork for the GCC driver: a compiler driver must spawn cc1/as/ld
and know whether each stage succeeded.

Kernel: the scheduler keeps an exit-code ledger (pid -> code; pids are
monotonic so entries never alias), published during teardown right
before waiters wake. SYS_EXIT records main()'s return value, SYS_KILL
records 256+SIGKILL, and the exception handler records 256+signal
mapped from the fault vector (#PF/#GP -> SIGSEGV, #DE/FP -> SIGFPE,
#UD -> SIGILL). SYS_WAITPID now returns the code: 0..255 for a normal
exit, 256+signal for a violent death. Process args grow from 256
bytes to 4 KiB (cc1 invocations do not fit in 256), with crt1 now
parsing up to 255 argv entries from a static buffer.

libc: new spawn.h with posix_spawn/posix_spawnp over SYS_SPAWN -
libiberty's pex layer has a posix_spawn backend, so GCC's driver works
without fork. argv is joined into the kernel args string (spaces in
arguments rejected; no kernel quoting), envp is not transferred, and
non-empty file actions fail loudly with ENOTSUP until the kernel can
redirect stdio on spawn. waitpid() now decodes real POSIX status and
the sys/wait.h macros distinguish exited from signaled children.

Shell: prints [exit code N] after nonzero exits and [terminated by
signal N] for killed or crashed children.

Verified on the OS: cat on a missing file reports exit code 1; a
window-close (clean exit 0) stays silent as it should.

Co-Authored-By: Claude Fable 5 <[email protected]>
This commit is contained in:
daniel
2026-07-16 16:59:17 +02:00
co-authored by Claude Fable 5
parent 54c0584b85
commit 75184e0651
19 changed files with 326 additions and 23 deletions
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programs/include/libc/sys/wait.h
+4 -4
View File
@@ -9,12 +9,12 @@
extern "C" {
#endif
/* Status decoding. The Montauk kernel does not yet report exit codes
through SYS_WAITPID, so waited children always decode as exit 0. */
/* POSIX status decoding. waitpid() encodes a normal exit as code<<8
and a killed/crashed child as the signal number in the low bits. */
#define WIFEXITED(s) (((s) & 0x7F) == 0)
#define WEXITSTATUS(s) (((s) >> 8) & 0xFF)
#define WIFSIGNALED(s) (0)
#define WTERMSIG(s) (0)
#define WIFSIGNALED(s) (((s) & 0x7F) != 0)
#define WTERMSIG(s) ((s) & 0x7F)
#define WIFSTOPPED(s) (0)
#define WSTOPSIG(s) (0)