commit db5d7fa965245a2791a0f2a1391040f002d5083c
parent e2945c26c09fde2545bc91e9c35a908fa18a03ff
Author: Mykyta Holubakha <hilobakho@gmail.com>
Date: Sat, 13 Mar 2021 18:32:59 +0200
rt: implement sigaction for signal handling
Added complete siginfo struct definition with necessary types.
Always use SA_RESTORER and add a restorer (copied over from musl), as not
providing a restorer (which is done by libc implicitly in C code) causes
segfaults on signal receipt.
Implemented restorers for amd64 and aarch64
Diffstat:
4 files changed, 166 insertions(+), 0 deletions(-)
diff --git a/rt/+aarch64/restore.s b/rt/+aarch64/restore.s
@@ -0,0 +1,11 @@
+// Copied from musl
+
+.global rt.restore
+.global rt.restore_si
+.type rt.restore,@function
+.type rt.restore_si,@function
+rt.restore:
+rt.restore_si:
+ mov x8,#139
+ svc 0
+
diff --git a/rt/+linux/syscalls.ha b/rt/+linux/syscalls.ha
@@ -344,3 +344,20 @@ export fn sigprocmask(
how: u64, set: uintptr: u64, old: uintptr: u64,
size(sigset): u64))?: int;
};
+
+fn restore() void;
+fn restore_si() void;
+
+export fn sigaction(
+ signum: int,
+ act: *const sigact,
+ old: nullable *sigact
+) (int | errno) = {
+ let real_act = *act;
+ real_act.sa_flags |= SA_RESTORER;
+ let restore_fn = if ((act.sa_flags & SA_SIGINFO) != 0) &restore_si else &restore;
+ real_act.sa_restorer = &restore;
+ return wrap_return(syscall4(SYS_rt_sigaction,
+ signum: u64, &real_act: uintptr: u64, old: uintptr: u64,
+ size(sigset): u64))?: int;
+};
diff --git a/rt/+linux/types.ha b/rt/+linux/types.ha
@@ -8,6 +8,12 @@ export type gid_t = uint;
export type time_t = i64;
export type suseconds_t = i64;
export type nfds_t = u64;
+export type pid_t = int;
+export type timer_t = int;
+export type clock_t = i64;
+export type si_band_t = i64;
+
+export def NSIG: int = 64;
export type sigset = struct {
__val: [1]u64,
@@ -331,6 +337,127 @@ export type pollfd = struct {
export def TFD_TIMER_ABSTIME: int = 1;
export def TFD_TIMER_CANCEL_ON_SET: int = 2;
+export def SIG_BLOCK: int = 0;
+export def SIG_UNBLOCK: int = 1;
+export def SIG_SETMASK: int = 2;
+
+def SI_MAX_SIZE: size = 128 / size(u8);
+
+export type sigval_t = union {
+ sival_t: int,
+ sival_ptr: *void,
+};
+
+
+//#define __ADDR_BND_PKEY_PAD (__alignof__(void *) < sizeof(short) ? sizeof(short) : __alignof__(void *))
+def __ADDR_BND_PKEY_PAD: size = 8;
+
+export type siginfo = union {
+ struct {
+ si_signo: int,
+ si_errno: int,
+ si_code: int,
+
+ union {
+ // kill()
+ struct {
+ si_pid: pid_t,
+ si_uid: u32,
+ },
+
+ // POSIX.1b timers
+ struct {
+ si_tid: timer_t,
+ si_overrun: int,
+ _sigval: sigval_t, // @ signals
+ si_sys_private: int,
+ },
+
+ // POSIX.1b signals
+ struct {
+ _sig_pid: pid_t, // @kill
+ _sig_uid: u32, // @ kill
+ union {
+ si_value: sigval_t,
+ si_int: int,
+ si_ptr: *void,
+ }
+ },
+
+ // SIGCHLD
+ struct {
+ _chld_pid: pid_t, // @ kill
+ _chld_uid: u32, // @ kill
+ si_status: int,
+ si_utime: clock_t,
+ si_stime: clock_t,
+ },
+
+ // SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT
+ struct {
+ si_addr: *void,
+
+ union {
+
+ // used when si_code=BUS_MCEERR_AR or
+ // used when si_code=BUS_MCEERR_AO
+ si_addr_lsb: i16,
+
+ struct {
+ _dummy_bnd: [__ADDR_BND_PKEY_PAD]u8,
+ si_lower: *void,
+ si_upper: *void,
+ },
+
+ struct {
+ _dummy_pkey: [__ADDR_BND_PKEY_PAD]u8,
+ si_pkey: u32,
+ },
+ },
+ },
+
+ // SIGPOLL
+ struct {
+ si_band: si_band_t,
+ si_fd: int,
+ },
+
+ // SIGSYS
+ struct {
+ si_call_addr: *void,
+ si_syscall: int,
+ si_arch: uint,
+ },
+
+ },
+ },
+ _si_pad: [SI_MAX_SIZE - 3 * size(int)]u8,
+};
+
+export def SA_NOCLDSTOP: u64 = 0x00000001;
+export def SA_NOCLDWAIT: u64 = 0x00000002;
+export def SA_SIGINFO: u64 = 0x00000004;
+export def SA_ONSTACK: u64 = 0x08000000;
+export def SA_RESTART: u64 = 0x10000000;
+export def SA_NODEFER: u64 = 0x40000000;
+export def SA_RESETHAND: u64 = 0x80000000;
+export def SA_NOMASK: u64 = SA_NODEFER;
+export def SA_ONESHOT: u64 = SA_RESETHAND;
+export def SA_RESTORER: u64 = 0x04000000;
+
+export type sigact = struct {
+ union {
+ sa_handler: *fn (int) void,
+ sa_sigaction: *fn (int, *siginfo, *void) void,
+ },
+ sa_flags: u64,
+ sa_restorer: *fn () void,
+ sa_mask: sigset,
+};
+
+export def SFD_NONBLOCK: int = O_NONBLOCK;
+export def SFD_CLOEXEC: int = O_CLOEXEC;
+
export type signalfd_siginfo = struct {
ssi_signo: u32,
ssi_errno: i32,
diff --git a/rt/+x86_64/restore.s b/rt/+x86_64/restore.s
@@ -0,0 +1,11 @@
+// Stolen from MUSL
+
+.global rt.restore
+.global rt.restore_si
+.type rt.restore,@function
+.type rt.restore_si,@function
+rt.restore:
+rt.restore_si:
+ movl $15, %eax
+ syscall
+
