303 lines
6.9 KiB
C
303 lines
6.9 KiB
C
/*
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* DOS Virtual Machine
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*
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* Copyright 1998 Ove Kåven
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*/
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#if defined(linux) && defined(__i386__)
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#include "config.h"
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/* apparently ELF images are usually loaded high anyway */
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#ifndef __ELF__
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/* if not, force dosmod at high addresses */
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asm(".org 0x110000");
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#endif /* __ELF__ */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <sys/stat.h>
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#ifdef HAVE_SYS_MMAN_H
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# include <sys/mman.h>
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#endif
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#ifdef HAVE_SYS_VM86_H
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# include <sys/vm86.h>
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#endif
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#include <sys/time.h>
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#include <sys/types.h>
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#ifdef HAVE_SYS_PTRACE_H
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# include <sys/ptrace.h>
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#endif
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#ifdef HAVE_SYS_WAIT_H
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# include <sys/wait.h>
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#endif
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#include "dosmod.h"
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/* FIXME: hack because libc vm86 may be the old syscall version */
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#define SYS_vm86 166
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static inline int vm86plus( int func, struct vm86plus_struct *ptr )
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{
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int res;
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#ifdef __PIC__
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__asm__ __volatile__( "pushl %%ebx\n\t"
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"movl %2,%%ebx\n\t"
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"int $0x80\n\t"
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"popl %%ebx"
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: "=a" (res)
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: "0" (SYS_vm86),
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"g" (func),
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"c" (ptr) );
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#else
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__asm__ __volatile__("int $0x80"
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: "=a" (res)
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: "0" (SYS_vm86),
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"b" (func),
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"c" (ptr) );
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#endif /* __PIC__ */
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if (res >= 0) return res;
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errno = -res;
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return -1;
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}
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int XREAD(int fd,void*buf,int size) {
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int res;
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while (1) {
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res = read(fd, buf, size);
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if (res==size)
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return res;
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if (res==-1) {
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if (errno==EINTR)
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continue;
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perror("dosmod read");
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return -1;
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}
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if (res) /* don't print the EOF condition */
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fprintf(stderr,"dosmod read only %d of %d bytes.\n",res,size);
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return res;
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}
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}
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int XWRITE(int fd,void*buf,int size) {
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int res;
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while (1) {
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res = write(fd, buf, size);
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if (res==size)
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return res;
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if (res==-1) {
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if (errno==EINTR)
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continue;
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perror("dosmod write");
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return -1;
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}
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fprintf(stderr,"dosmod write only %d of %d bytes.\n",res,size);
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return res;
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}
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}
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void set_timer(struct timeval*tim)
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{
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struct itimerval cur;
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cur.it_interval=*tim;
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cur.it_value=*tim;
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setitimer(ITIMER_REAL,&cur,NULL);
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}
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void get_timer(struct timeval*tim)
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{
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struct itimerval cur;
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getitimer(ITIMER_REAL,&cur);
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*tim=cur.it_value;
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}
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volatile int sig_pend,sig_fatal=0,sig_alrm=0,sig_cb=0;
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void*img;
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struct vm86plus_struct VM86;
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void sig_handler(int sig)
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{
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if (sig_pend) fprintf(stderr,"DOSMOD previous signal %d lost\n",sig_pend);
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sig_pend=sig;
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signal(sig,sig_handler);
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}
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void bad_handler(int sig)
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{
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if (sig!=SIGTERM) {
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fprintf(stderr,"DOSMOD caught fatal signal %d\n",sig);
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fprintf(stderr,"(Last known VM86 CS:IP was %04x:%04lx)\n",VM86.regs.cs,VM86.regs.eip);
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}
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sig_pend=sig; sig_fatal++;
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signal(sig,bad_handler);
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}
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void alarm_handler(int sig)
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{
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sig_alrm++;
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signal(sig,alarm_handler);
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}
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void cb_handler(int sig)
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{
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sig_cb++;
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signal(sig,cb_handler);
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}
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int send_signal(void)
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{
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int ret=sig_pend; sig_pend=0;
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if (!ret) {
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if (sig_alrm) {
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ret=SIGALRM; sig_alrm--;
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} else {
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ret=SIGUSR2; sig_cb--;
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}
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}
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if (XWRITE(1,&ret,sizeof(ret))!=sizeof(ret)) return 1;
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if (sig_fatal) return 1;
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return 0;
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}
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int send_enter_reply(int ret)
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{
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if (XWRITE(1,&ret,sizeof(ret))!=sizeof(ret)) return 1;
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if (XWRITE(1,&VM86,sizeof(VM86))!=sizeof(VM86)) return 1;
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switch (ret&0xff) {
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case DOSMOD_SIGNAL:
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return send_signal();
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}
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return 0;
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}
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int main(int argc,char**argv)
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{
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int mfd=open(argv[0],O_RDWR);
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struct timeval tim;
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mprot_info mpr;
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int func,ret,idle;
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off_t fofs=0;
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pid_t ppid=getppid();
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/* fprintf(stderr,"main is at %08lx, file is %s, fd=%d\n",(unsigned long)&main,argv[0],mfd); */
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if (mfd<0) return 1;
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/* Map in our DOS image at the start of the process address space */
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if (argv[1]) {
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/* Ulrich Weigand suggested mapping in the DOS image directly from the Wine
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address space */
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fofs=atol(argv[1]);
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/* linux currently only allows mapping a process memory if it's being ptraced */
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/* Linus doesn't like it, so this probably won't work in the future */
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/* it doesn't even work for me right now */
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kill(ppid,SIGSTOP);
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ptrace(PTRACE_ATTACH,ppid,0,0);
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waitpid(ppid,NULL,0);
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}
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img=mmap(NULL,0x110000,PROT_EXEC|PROT_READ|PROT_WRITE,MAP_FIXED|MAP_SHARED,mfd,fofs);
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if (argv[1]) {
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ptrace(PTRACE_DETACH,ppid,0,0);
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kill(ppid,SIGCONT);
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}
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if (img==(void*)-1) {
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fprintf(stderr,"DOS memory map failed, error=%s\n",strerror(errno));
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fprintf(stderr,"in attempt to map %s, offset %08lX, length 110000, to offset 0\n",argv[0],fofs);
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return 1;
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}
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/* initialize signals and system timer */
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signal(SIGHUP,sig_handler);
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signal(SIGINT,sig_handler);
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signal(SIGUSR1,sig_handler);
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signal(SIGUSR2,cb_handler);
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signal(SIGALRM,alarm_handler);
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signal(SIGQUIT,bad_handler);
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signal(SIGILL,bad_handler);
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signal(SIGBUS,bad_handler);
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signal(SIGFPE,bad_handler);
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signal(SIGSEGV,bad_handler);
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signal(SIGTERM,bad_handler);
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#if 0
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tim.tv_sec=0; tim.tv_usec=54925;
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set_timer(&tim);
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#endif
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/* report back to the main program that we're ready */
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ret=3; /* dosmod protocol revision */
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XWRITE(1,&ret,sizeof(ret));
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/* context exchange loop */
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idle=0;
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do {
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if (idle) {
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while (1) {
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int res;
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/* parent is idle, transmit any signals (particularly SIGALRM) */
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if (sig_pend||sig_alrm||sig_cb) {
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ret=DOSMOD_SIGNAL;
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if (XWRITE(1,&ret,sizeof(ret))!=sizeof(ret)) return 1;
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ret=send_signal();
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if (ret) return ret;
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break;
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}
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res = read(0,&func,sizeof(func));
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if (res==sizeof(func))
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break;
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if (res==-1) {
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if (errno==EINTR)
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continue;
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perror("dosmod read");
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return 1;
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}
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if (res) /* don't print the EOF condition */
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fprintf(stderr,"dosmod read only %d of %d bytes.\n",res,sizeof(func));
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return 1;
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}
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ret=DOSMOD_LEFTIDLE;
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if (XWRITE(1,&ret,sizeof(ret))!=sizeof(ret)) return 1;
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idle--;
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} else
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if (XREAD(0,&func,sizeof(func))!=sizeof(func)) return 1;
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if (func<0) break;
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switch (func) {
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case DOSMOD_SET_TIMER: /* rev 1 */
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if (XREAD(0,&tim,sizeof(tim))!=sizeof(tim)) return 1;
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set_timer(&tim);
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/* no response */
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break;
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case DOSMOD_GET_TIMER: /* rev 1 */
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get_timer(&tim);
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if (XWRITE(1,&tim,sizeof(tim))!=sizeof(tim)) return 1;
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break;
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case DOSMOD_MPROTECT: /* rev 3 */
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if (XREAD(0,&mpr,sizeof(mpr))!=sizeof(mpr)) return 1;
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mprotect(mpr.addr,mpr.len,mpr.prot);
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/* no response */
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break;
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case DOSMOD_ENTERIDLE: /* rev 3 */
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idle++;
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break;
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case DOSMOD_LEAVEIDLE: /* rev 3 */
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break;
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case DOSMOD_ENTER: /* rev 0 */
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default:
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if (XREAD(0,&VM86,sizeof(VM86))!=sizeof(VM86)) return 1;
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if (sig_pend||sig_alrm||sig_cb) ret=DOSMOD_SIGNAL; else
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ret=vm86plus(func,&VM86);
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ret=send_enter_reply(ret);
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if (ret) return ret;
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}
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} while (1);
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return 0;
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}
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#else /* !linux-i386 */
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int main(void) {return 1;}
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#endif
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