From 8cdf2532d42de683f41e9b1816484a62e1694867 Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@pond.sub.org>
Date: Fri, 14 Dec 2007 07:26:30 +0000
Subject: [PATCH] (recvline): Rewrite the loop to receive a line from a socket.
  The new version silently truncates long lines.  The old one split them up
 and got quite confused.  It got also confused when the line didn't arrive in
 one piece.  Icing on the cake: it wrote beyond the end of the buffer.  The
 new version is less efficient, but that doesn't matter here.

---
 src/client/expect.c | 74 +++++++++++++++------------------------------
 1 file changed, 25 insertions(+), 49 deletions(-)

diff --git a/src/client/expect.c b/src/client/expect.c
index b681668a6..7e27b515d 100644
--- a/src/client/expect.c
+++ b/src/client/expect.c
@@ -29,6 +29,7 @@
  * 
  *  Known contributors to this file:
  *      Steve McClure, 1998
+ *      Markus Armbruster, 2007
  */
 
 #include <config.h>
@@ -46,8 +47,6 @@
 #include "misc.h"
 
 #ifdef _WIN32
-#define recv(sock, buffer, buf_size, flags) \
-	w32_recv((sock), (buffer), (buf_size), (flags))
 #define read(sock, buffer, buf_size) \
 	w32_recv((sock), (buffer), (buf_size), 0)
 #define write(sock, buffer, buf_size) \
@@ -57,56 +56,33 @@
 int
 recvline(int s, char *buf)
 {
-    int size;
-    char *p;
-    int n;
-    int newline;
-    char *ptr;
-    int cc;
+    int sz = 1024;
+    char *bp;
+    char ch;
+    ssize_t n;
 
-    size = 1024;
-    ptr = buf;
-    n = recv(s, ptr, size, MSG_PEEK);
-    if (n <= 0) {
-	perror("recv");
-	return 0;
-    }
-    size -= n;
-    buf[n] = '\0';
-    if ((p = strchr(ptr, '\n')) == NULL) {
-	do {
-	    cc = read(s, ptr, n);
-	    if (cc < 0) {
-		perror("expect: read");
-		return 0;
-	    }
-	    if (cc != n) {
-		fprintf(stderr, "expect: short read (%d not %d)\n", cc, n);
-		return 0;
-	    }
-	    ptr += n;
-	    if ((n = recv(s, ptr, size, MSG_PEEK)) <= 0) {
-		perror("recv");
-		return 0;
+    bp = buf;
+    for (;;) {
+	n = read(s, &ch, 1);
+	if (n < 0) {
+	    if (errno != EINTR) {
+		perror("read");
+		exit(1);
 	    }
-	    size -= n;
-	    ptr[n] = '\0';
-	} while ((p = strchr(ptr, '\n')) == 0);
-	newline = 1 + p - buf;
-	*p = 0;
-    } else
-	newline = 1 + p - ptr;
-    cc = read(s, buf, newline);
-    if (cc < 0) {
-	perror("expect: read #2");
-	return 0;
-    }
-    if (cc != newline) {
-	fprintf(stderr, "expect: short read #2 (%d not %d)\n",
-		cc, newline);
-	return 0;
+	    continue;
+	}
+	if (n == 0)
+	    return -1;
+	if (ch == '\n')
+	    break;
+	if (bp < buf + sz - 2)
+	    *bp++ = ch;
+	/* else silently truncate */
     }
-    buf[newline] = '\0';
+
+    *bp++ = ch;
+    *bp = 0;
+
     if (!isxdigit(buf[0]) || buf[1] != ' ') {
 	fprintf(stderr, "Malformed line %s\n", buf);
 	return 0;
-- 
2.43.0