#ifdef PLAN9#include <u.h>#include <libc.h>#include <ctype.h>#else#include <stdio.h>#include "linux.h"#endif #include "dat.h"#include "hash.h"#include "pstring.h" /* This comes directly from the Plan 9 libc source */longreadn(int f, void *av, long n){	char *a;	long m, t; 	a = av;	t = 0;	while(t < n){		m = read(f, a+t, n-t);		if(m <= 0){			if(t == 0)				return m;			break;		}		t += m;	}	return t;}  void errorreply(Client *c, char* s){	if (s) {		fprint(c->fd, "-%s\r\n", s);	}} voidstatusreply(Client *c, char* s){	if (s) {		fprint(c->fd, "+%s\r\n", s);	}} voidbulkreply(Client *c, pstring *s){	if (s) {		fprint(c->fd, "$%d\r\n", s->length);		write(c->fd, s->data, s->length);		fprint(c->fd, "\r\n");	}} voidnilreply(Client *c){	fprint(c->fd, "$-1\r\n");} intgethandler(Client *c){	pstring *r; //	print("get: fd %d\n", fd);	r = get(ht, c->args[1]);	if (r == nil) {		nilreply(c);		return 0;	}	bulkreply(c, r);	freepstring(r);	return 0;} intsethandler(Client *c){//	print("set: fd %d\n", fd);	set(ht, c->args[1], c->args[2]);	statusreply(c, "OK");	return 0;} intquithandler(Client *c){	close(c->fd);	exits(0);	return 0; // this is stupid, but it keeps the compiler quiet} Command commands[] = {	{"get", gethandler, 1},	{"set", sethandler, 2},	{"quit", quithandler, 0},}; /* Clean up the client, deallocating stuff if needed. If done is set, will close the fd and exit the current thread*/voidcleanclient(Client *c, int done){	int i; 	if (c->args != nil)		for (i = 0; i < c->nargs; i++) {			freepstring(c->args[i]);		}	free(c->args); // according to malloc(2), this is safe even if args is nil	c->args = nil;	if (done) {		close(c->fd);		exits(0);	}} int readnum(int sockd, void *vptr, int maxlen) {	int n, rc;	char	c, *buffer; 	buffer = vptr; 	for ( n = 1; n < maxlen; n++ ) {		if ( (rc = readn(sockd, &c, 1)) == 1 ) {			*buffer++ = c;			if ( c == '\n' && *(buffer-2) == '\r') {				*(buffer-1) = 0;				break;			}		} else if ( rc <= 0 ) {			close(sockd);			exits(0);		}	} 	*buffer = 0; 	n = atoi(vptr);	return n;} // Read a string (possibly binary) off the line. It is of the form:// <len bytes>\r\n// Toss out the CRLF and create a p-string from the data.pstring*readpstring(int fd, int len){	int n;	char c;	pstring *result; 	result = mallocz(sizeof(pstring), 1); 	result->length = len;	result->data = mallocz(sizeof(unsigned char)*len, 1); 	n = readn(fd, result->data, len); 	if (n != len) 		goto readerr; 	n = readn(fd, &c, 1);	if (n != 1 || c != '\r')		goto readerr; 	n = readn(fd, &c, 1);	if (n != 1 || c != '\n')		goto readerr; 	return result; readerr:	free(result->data);	free(result);	if (n <= 0) {		close(fd);		exits(0);	}	return nil;} voidhandler(int fd){	Client c;	int n, arglen, i;	pstring *tmp;	char buf[128];	int foundcommand = 0;	char *s; 	//print("new client fd = %d\n", fd); 	c.fd = fd; 	for (;;) {		/* All commands start with '*' followed by the # of arguments */		n = readn(fd, buf, 1);		if (n != 1 || buf[0] != '*') {			if (n <= 0)				cleanclient(&c, 1);			errorreply(&c, "ERROR");			cleanclient(&c, 0);			continue;		} 		c.nargs = readnum(fd, buf, 128);		if (c.nargs <= 0) {			errorreply(&c, "ERROR");			cleanclient(&c, 0);			continue;		} 		c.args = mallocz(sizeof(pstring*)*c.nargs, 1); 		// Read in the arguments		for (i = 0; i < c.nargs; i++) {			n = readn(fd, buf, 1);			if ((buf[0] != '$') || (n != 1)) {				if (n <= 0) { cleanclient(&c, 1); }				errorreply(&c, "ERROR");				cleanclient(&c, 0);				break;			}				arglen = readnum(fd, buf, 128);			if (arglen <= 0) {				errorreply(&c, "ERROR");				cleanclient(&c, 0);				break;			}				tmp = readpstring(fd, arglen);			if (tmp == nil) {				errorreply(&c, "ERROR");				cleanclient(&c, 0);				break;			}				c.args[i] = tmp;		} 		// Make sure we successfully finished the loop		// c.args will be nil if we had an error		if (!c.args)			continue; 		// we do all the commands as lower case for simplicity		pstringtolower(c.args[0]); 		for (i = 0; i < (sizeof(commands)/sizeof(commands[0])); i++) {			// I apologize for this conditional			if (!memcmp(c.args[0]->data, commands[i].name, (c.args[0]->length < strlen(commands[i].name) ? c.args[0]->length : strlen(commands[i].name))) && c.nargs - 1 == commands[i].nargs) {				foundcommand = 1;				(commands[i].proc)(&c);				break;			}		}		if (!foundcommand) {			s = pstring2cstring(c.args[0]);			print("unknown command %s\n", s);			free(s);		}		cleanclient(&c, 0);	}}