#include <u.h>#include <libc.h>#include <bio.h>#include <mach.h> static	char	*kernelfile = "/power/ipaq";ulong	crc32(void *buf, int n, ulong crc); voidmain(int argc, char **argv){	int ifd, n;	char buf[64], reply[1];	int i, execsize;	Fhdr f;	ulong csum; 	ARGBEGIN{	}ARGEND	ifd = open(kernelfile, OREAD);	if(ifd < 0){		fprint(2, "dload: can't open %s: %r\n", kernelfile);		exits("open");	}	i = 0;	if(crackhdr(ifd, &f) == 0){		fprint(2, "dload: not an executable file: %r\n");		exits("format");	}	if(f.magic != Q_MAGIC){		fprint(2, "dload: not a powerpc executable\n");		exits("format");	}	execsize = f.txtsz + f.datsz + f.txtoff;	seek(ifd, 0, 0);	csum = ~0;	while(execsize > 0 && (n = read(ifd, buf, sizeof(buf))) > 0){		if(n > execsize)			n = execsize;		for(;;){			if(write(1, buf, sizeof(buf)) != sizeof(buf)){	/* always writes full buffer */				fprint(2, "dload: write error: %r\n");				exits("write");			}			if(read(0, reply, 1) != 1){				fprint(2, "dload: bad reply\n");				exits("read");			}			if(reply[0] != 'n')				break;			fprint(2, "!");		}		if(reply[0] != 'y'){			fprint(2, "dload: bad ack: %c\n", reply[0]);			exits("reply");		}		if(++i%10 == 0)			fprint(2, ".");		execsize -= n;	}	exits(0);} /* * from Rob Warnock */static	ulong	crc32tab[256];	/* initialised on first call to crc32 */ enum {	CRC32POLY = 0x04c11db7     /* AUTODIN II, Ethernet, & FDDI */}; /* * Build auxiliary table for parallel byte-at-a-time CRC-32. */static voidinitcrc32(void){	int i, j;	ulong c; 	for(i = 0; i < 256; i++) {		for(c = i << 24, j = 8; j > 0; j--)			if(c & (1<<31))				c = (c<<1) ^ CRC32POLY;			else				c <<= 1;		crc32tab[i] = c;	}} ulongcrc32(void *buf, int n, ulong crc){	uchar *p; 	if(crc32tab[1] == 0)		initcrc32();	crc = ~crc;	for(p = buf; --n >= 0;)		crc = (crc << 8) ^ crc32tab[(crc >> 24) ^ *p++];	return ~crc;}