libauthsrv: export common readcons() routine and introduce PASSWDLEN constant

drawterm, factotum, secstore and the auth commands
all had ther own implementation of readcons. we
want to have one common function for this to avoid
the duplication, so putting that in libauthsrv.

introduce PASSWDLEN which makes the use more explicit
than ANAMELEN.

sys/include/authsrv.h

@@ -26,6 +26,7 @@ enum
 	NETCHLEN=	16,	/* max network challenge length (used in AS protocol) */
 	CONFIGLEN=	14,
 	SECRETLEN=	32,	/* secret max size */
+	PASSWDLEN=	28,	/* password max size */
 
 	NONCELEN=	32,
 
@@ -102,8 +103,8 @@ struct Authenticator
 struct Passwordreq
 {
 	char	num;
-	char	old[ANAMELEN];
-	char	new[ANAMELEN];
+	char	old[PASSWDLEN];
+	char	new[PASSWDLEN];
 	char	changesecret;
 	char	secret[SECRETLEN];	/* new secret */
 };
@@ -187,6 +188,7 @@ struct Nvrsafe
 
 extern	uchar	nvcsum(void*, int);
 extern	int	readnvram(Nvrsafe*, int);
+extern	char*	readcons(char*, char*, int);
 
 /*
  *  call up auth server

sys/src/libauthsrv/mkfile

@@ -21,6 +21,7 @@ OFILES=\
 	nvcsum.$O\
 	passtokey.$O\
 	readnvram.$O\
+	readcons.$O\
 
 HFILES=\
 	/sys/include/authsrv.h

sys/src/libauthsrv/passtokey.c

@@ -6,12 +6,12 @@
 void
 passtodeskey(char key[DESKEYLEN], char *p)
 {
-	uchar buf[ANAMELEN], *t;
+	uchar buf[PASSWDLEN], *t;
 	int i, n;
 
 	n = strlen(p);
-	if(n >= ANAMELEN)
-		n = ANAMELEN-1;
+	if(n >= PASSWDLEN)
+		n = PASSWDLEN-1;
 	memset(buf, ' ', 8);
 	t = buf;
 	strncpy((char*)t, p, n);

sys/src/libauthsrv/readcons.c

@@ -0,0 +1,82 @@
+#include <u.h>
+#include <libc.h>
+
+/*
+ *  prompt for a string with a possible default response
+ */
+char*
+readcons(char *prompt, char *def, int raw)
+{
+	int fdin, fdout, ctl, n;
+	char *s, *p;
+
+	s = p = nil;
+	fdout = ctl = -1;
+
+	if((fdin = open("/dev/cons", OREAD)) < 0)
+		goto Out;
+	if((fdout = open("/dev/cons", OWRITE)) < 0)
+		goto Out;
+
+	if(raw){
+		if((ctl = open("/dev/consctl", OWRITE)) < 0)
+			goto Out;
+		write(ctl, "rawon", 5);
+	}
+
+	if(def != nil)
+		fprint(fdout, "%s[%s]: ", prompt, def);
+	else
+		fprint(fdout, "%s: ", prompt);
+
+	for(;;){
+		n = p - s;
+		if((n % 32) == 0){
+			if((p = realloc(s, n+32)) == nil)
+				break;
+			s = p, p += n;
+		}
+
+		if(read(fdin, p, 1) <= 0 || *p == 0x7f)
+			break;
+
+		if(*p == '\n' || *p == '\r'){
+			if(p == s && def != nil){
+				free(s);
+				s = strdup(def);
+			} else
+				*p = 0;
+			if(raw)
+				write(fdout, "\n", 1);
+			goto Out;
+		} else if(*p == '\b') {
+			while(p > s && (p[-1] & 0xc0) == 0x80)
+				*p-- = 0;
+			if(p > s)
+				*p-- = 0;
+		} else if(*p == 0x15) {	/* ^U: line kill */
+			if(def != nil)
+				fprint(fdout, "\n%s[%s]: ", prompt, def);
+			else
+				fprint(fdout, "\n%s: ", prompt);
+			while(p > s)
+				*p-- = 0;
+		} else if(*p >= ' ')
+			p++;
+	}
+	free(s);
+	s = nil;
+	if(raw)
+		write(fdout, "\n", 1);
+Out:
+	if(ctl >= 0){
+		write(ctl, "rawoff", 6);
+		close(ctl);
+	}
+	if(fdin >= 0)
+		close(fdin);
+	if(fdout >= 0)
+		close(fdout);
+
+	return s;
+}

sys/src/libauthsrv/readnvram.c

@@ -53,78 +53,6 @@ static struct {
 	"debug", "/tmp/nvram", 0, sizeof(Nvrsafe),
 };
 
-static char*
-readcons(char *prompt, char *def, int raw, char *buf, int nbuf)
-{
-	int fdin, fdout, ctl, n, m;
-	char line[10];
-
-	fdin = open("/dev/cons", OREAD);
-	if(fdin < 0)
-		fdin = 0;
-	fdout = open("/dev/cons", OWRITE);
-	if(fdout < 0)
-		fdout = 1;
-	if(def != nil)
-		fprint(fdout, "%s[%s]: ", prompt, def);
-	else
-		fprint(fdout, "%s: ", prompt);
-	if(raw){
-		ctl = open("/dev/consctl", OWRITE);
-		if(ctl >= 0)
-			write(ctl, "rawon", 5);
-	} else
-		ctl = -1;
-
-	m = 0;
-	for(;;){
-		n = read(fdin, line, 1);
-		if(n == 0){
-			close(ctl);
-			werrstr("readcons: EOF");
-			return nil;
-		}
-		if(n < 0){
-			close(ctl);
-			werrstr("can't read cons");
-			return nil;
-		}
-		if(line[0] == 0x7f)
-			exits(0);
-		if(n == 0 || line[0] == '\n' || line[0] == '\r'){
-			if(raw){
-				write(ctl, "rawoff", 6);
-				write(fdout, "\n", 1);
-				close(ctl);
-			}
-			buf[m] = '\0';
-			if(buf[0]=='\0' && def)
-				strcpy(buf, def);
-			return buf;
-		}
-		if(line[0] == '\b'){
-			if(m > 0)
-				m--;
-		}else if(line[0] == 0x15){	/* ^U: line kill */
-			m = 0;
-			if(def != nil)
-				fprint(fdout, "%s[%s]: ", prompt, def);
-			else
-				fprint(fdout, "%s: ", prompt);
-		}else{
-			if(m >= nbuf-1){
-				fprint(fdout, "line too long\n");
-				m = 0;
-				if(def != nil)
-					fprint(fdout, "%s[%s]: ", prompt, def);
-				else
-					fprint(fdout, "%s: ", prompt);
-			}else
-				buf[m++] = line[0];
-		}
-	}
-}
-
 typedef struct {
 	int	fd;
 	int	safelen;
@@ -211,6 +139,29 @@ findnvram(Nvrwhere *locp)
 	locp->safeoff = safeoff;
 }
 
+static int
+ask(char *prompt, char *buf, int len, int raw)
+{
+	char *s;
+	int n;
+
+	memset(buf, 0, len);
+	for(;;){
+		if((s = readcons(prompt, nil, raw)) == nil)
+			return -1;
+		if((n = strlen(s)) >= len)
+			fprint(2, "%s longer than %d characters; try again\n", prompt, len-1);
+		else {
+			memmove(buf, s, n);
+			memset(s, 0, n);
+			free(s);
+			return 0;
+		}
+		memset(s, 0, n);
+		free(s);
+	}
+}
+
 /*
  *  get key info out of nvram.  since there isn't room in the PC's nvram use
  *  a disk partition there.
@@ -219,7 +170,7 @@ int
 readnvram(Nvrsafe *safep, int flag)
 {
 	int err;
-	char buf[512], in[128];		/* 512 for floppy i/o */
+	char buf[512];		/* 512 for floppy i/o */
 	Nvrsafe *safe;
 	Nvrwhere loc;
 
@@ -294,22 +245,22 @@ readnvram(Nvrsafe *safep, int flag)
 
 	if((flag&(NVwrite|NVwritemem)) || (err && (flag&NVwriteonerr))){
 		if (!(flag&NVwritemem)) {
-			readcons("authid", nil, 0, safe->authid,
-					sizeof safe->authid);
-			readcons("authdom", nil, 0, safe->authdom,
-					sizeof safe->authdom);
-			readcons("secstore key", nil, 1, safe->config,
-					sizeof safe->config);
-			for(;;){
-				Authkey k;
+			char pass[PASSWDLEN];
+			Authkey k;
 
-				if(readcons("password", nil, 1, in, sizeof in) == nil)
-					goto Out;
-				passtokey(&k, in);
-				memmove(safe->machkey, k.des, DESKEYLEN);
-				memmove(safe->aesmachkey, k.aes, AESKEYLEN);
-				break;
-			}
+			if(ask("authid", safe->authid, sizeof safe->authid, 0))
+				goto Out;
+			if(ask("authdom", safe->authdom, sizeof safe->authdom, 0))
+				goto Out;
+			if(ask("secstore key", safe->config, sizeof safe->config, 1))
+				goto Out;
+			if(ask("password", pass, sizeof pass, 1))
+				goto Out;
+			passtokey(&k, pass);
+			memset(pass, 0, sizeof pass);
+			memmove(safe->machkey, k.des, DESKEYLEN);
+			memmove(safe->aesmachkey, k.aes, AESKEYLEN);
+			memset(&k, 0, sizeof k);
 		}
 
 		safe->machsum = nvcsum(safe->machkey, DESKEYLEN);