86 lines
2.2 KiB
C
86 lines
2.2 KiB
C
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#ifndef _SIGNAL_H
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#define _SIGNAL_H
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#include <stdc_common.h>
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typedef long sig_atomic_t; // there are no "asynchronous interrupts"
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#define SIG_DFL 0
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#define SIG_IGN _sig_ign
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#define SIG_ERR (-1)
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typedef void (*_Sighandler)(int);
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struct sigaction {
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void (*handler)(int);
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unsigned long flags;
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void (*restorer)(void);
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unsigned long mask;
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};
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unsigned char _signal_restorer[] = {
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0x48,0xb8,15,0,0,0,0,0,0,0, // mov rax, 15 (sigreturn)
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0x0f,0x05 // syscall
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};
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#define _SIGNAL_HANDLERS 0xfff000
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#define _LE64(x) (x)&0xff, ((x)>> 8)&0xff, ((x)>>16)&0xff, ((x)>>24)&0xff, \
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((x)>>32)&0xff, ((x)>>40)&0xff, ((x)>>48)&0xff, (x)>>56
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// we need to do this weird indirection because linux has a different
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// calling convention from us.
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unsigned char _signal_handler[] = {
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// signal # passed in rdi
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0x48,0x89,0xf8, // mov rax, rdi (signal #)
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0x50, // push rax
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0x50, // push rax (allocate space for return value)
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0x48,0xb8,_LE64(_SIGNAL_HANDLERS), // mov rax, _SIGNAL_HANDLERS
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0x48,0x89,0xc3, // mov rbx, rax
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0x48,0x89,0xf8, // mov rax, rdi (signal #)
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0x48,0xc1,0xe0,0x03, // shl rax, 3
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0x48,0x01,0xd8, // add rax, rbx
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0x48,0x89,0xc3, // mov rbx, rax
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0x48,0x8b,0x03, // mov rax, [rbx]
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0xff,0xd0, // call rax
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0x48,0x81,0xc4,16,0,0,0, // add rsp, 16
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0xc3 // ret
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};
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#define _SA_RESTORER 0x04000000
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int __sigaction(int signum, const struct sigaction *act, struct sigaction *oldact) {
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return __syscall(13, signum, act, oldact, 8, 0, 0);
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}
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void _sig_ign(int signal) {
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return;
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}
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static unsigned long _sig_mask = 0;
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_Sighandler signal(int sig, _Sighandler func) {
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if (func == SIG_DFL) {
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// @TODO
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return 0;
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}
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if (func == SIG_IGN) {
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func = _sig_ign;
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}
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void **handlers = _SIGNAL_HANDLERS;
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handlers[sig] = func;
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_sig_mask |= 1ul << (sig-1);
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struct sigaction act = {0};
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act.handler = _signal_handler;
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act.mask = _sig_mask;
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act.flags = _SA_RESTORER;
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act.restorer = _signal_restorer;
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__sigaction(sig, &act, NULL);
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return 0;//@TODO
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}
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#endif // _SIGNAL_H
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