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.

1 files changed, 39 insertions, 88 deletions

diff --git a/sys/src/libauthsrv/readnvram.c b/sys/src/libauthsrv/readnvram.c
index ae708acbc..1a00835cf 100644
--- a/sys/src/libauthsrv/readnvram.c
+++ b/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);